Professor Mary Bebawy has a PhD in Pharmacy (USYD) and Head of the Laboratory of Cancer Cell Biology and Therapeutics, Graduate School of Health UTS. She has an active research portfolio focusing on the molecular basis of cancer relapse. She is an internationally recognized cancer researcher and pharmaceutical scientist with a background in commercial R & D. Her team were the first to discover the role of extracellular vesicles (EVs) in the spread of cancer multidrug resistance (MDR) (Bebawy et al., 2009). Since this discovery, Prof Bebawy and her team were the first to also discover that EVs can re-template the proteome and transcriptome of cancer cells to ensure the transfer and dominance of cancer traits within cell populations (Jaswail et al., 2012; Lu et al., 2013; Pokharel et al., 2014; Gong et al., 2013; 2014).These findings have since been translated clinically with her team discovering the utility of EVs as a prognostic in Myeloma (Krishnan et al., 2016), PCT/AU2018/050420.
Her national and international standing has been recognised on numerous occasions, including a recent invitation by “Women in Science Australia” to showcase her achievements as part of activities to promote research excellence in Australia. On the international stage, she receives many invitations to speak at prestigious scientific meetings and international research institutes. including Harvard Medical School, Boston Ma. 2017, Queens Cancer Research Institute, Kingston Canada, Cold Spring Harbour laboratories Microenvironment, Metastasis & Therapeutics, NY May 2015; AACR Precision Medicines Series, FL USA- Drug sensitivity and resistance: Improving cancer therapy; Albert Einstein College of Medicine, NY, Jul 2014. Her research has been showcased twice in SMH 8/10/2012 and 18/07/2013.
More recently, her reflections have been included in a book by Prof. Deborah Edwards et al, The Power of Conferences, Stories of serendipity, innovation, and driving social change.
Prof Bebawy served as the inaugral Director of Research and Innovation for the GSH (Jul 2011-Mar 2017).
Prof Bebawy is an experienced doctoral supervisor and welcomes research degree enquiries via a formal expression of interest (please do not email directly).
Can supervise: YES
Prof Bebawy's interest is in the molecular basis of cancer multidrug resistance and disease relapse. She has made contributions advancing this field:
She developed a continuous fluorescence assay for the study of the drug efflux of an ABC membrane transporter, P-glycoprotein (P-gp) responsible for confering multidrug resistance in cancer. She developed a novel assay using inside-out membrane vesicles (Bebawy et al., 1999 Analytical Biochemistry 268(2):270-277), which provided researchers with a innovative approach in characterizing anticancer drug efflux kinetics continuously using simplified biological models. The work led to the important finding that P-gp transport function, and subsequently multidrug resistance in cancer, was differentially modulated depending on the drug combination used and the site of interaction within the plasma membrane bilayer (Bebawy et al., 2001 British Journal of Cancer 85(12) 1998-2003; Huang, Bebawy et al., 2007 Phytomedicine 14(12) 830-839).
In 2009 she published in Leukemia the breakthrough discovery that intercellular transfer of Pgp-containing extracellular vesicles is a process underlying the transfer of Pgp from donor to recipient cancer cells, i.e. is a process by which a cell can acquire multidrug resistance. A non-genetic process, it is a change away from earlier ways of thinking about MDR as being acquired only through mutation, either innate, or as cells adapted to drug exposure. Following this discovery, her research has been increasingly directed at understanding local and distal intercellular communication from multidrug resistant cells, the roles of vesicles and the nature of functional changes effected them. Amoung her contributions she showed that:
· Extracellular vesicles shed from drug resistant donor cells can ‘re-template’ the protein and transcriptional landscape of drug sensitive recipient cells to reflect the donor cell trait.
· Extracellular vesicles shed from drug resistant donor cells confer resistance in a tissue selective manner and provide an alternate and parallel mechanism of resistance through active and passive drug sequestration and immune evasion.
· An interaction complex is required for effective dissemination of multidrug resistance and the multidrug resistant state confers enhanced metastatic capacity in cancer.
· Using homotypic cell models, the nucleic acid cargo of extracellular vesicles shed from drug resistant donor cells is functional and translatable in recipient cells .
· A novel mechanism governing the transcriptional regulation and functional redundancy of ABC transporters in MDR cancer cells is mediated through extracelular transfer of miRNA326
· Extracellular vesicles shed from drug resistant cells alter the biomechanical properties of recipient cells through the transfer of CD44 and P-gp
Prof Bebawy was a founding member of the Discipline of Pharmacy and Graduate School of Health at UTS. She was instrumental in developing the pharmaceutical sciences curriculum together with the two research elective units for the MPharm Degree at the Graduate School of Health, UTS. She has years of curriculum development and teaching experience across all the pharmaceutical sciences subdiciplines including;
Pharmaceutics and Formulation science
De Rubis, G, Rajeev Krishnan, S & Bebawy, M 2019, 'Liquid Biopsies in Cancer Diagnosis, Monitoring, and Prognosis.', Trends in pharmacological sciences, vol. 40, no. 3, pp. 172-186.View/Download from: UTS OPUS or Publisher's site
Liquid biopsies, comprising the noninvasive analysis of circulating tumor-derived material (the 'tumor circulome'), represent an innovative tool in precision oncology to overcome current limitations associated with tissue biopsies. Within the tumor circulome, circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs) are the only components the clinical application of which is approved by the US Food and Drug Administration (FDA). Extracellular vesicles (EVs), circulating tumor RNA (ctRNA), and tumor-educated platelets (TEPs) are relatively new tumor circulome constituents with promising potential at each stage of cancer management. Here, we discuss the clinical applications of each element of the tumor circulome and the prevailing factors that currently limit their implementation in clinical practice. We also detail the most recent technological developments in the field, which demonstrate potential in improving the clinical value of liquid biopsies.
Taylor, J & Bebawy, M 2019, 'Proteins Regulating Microvesicle Biogenesis and Multidrug Resistance in Cancer.', Proteomics, vol. 19, no. 1-2, pp. e1800165-e1800165.View/Download from: UTS OPUS or Publisher's site
Microvesicles (MV) are emerging as important mediators of intercellular communication. While MVs are important signaling vectors for many physiological processes, they are also implicated in cancer pathology and progression. Cellular activation is perhaps the most widely reported initiator of MV biogenesis, however, the precise mechanism remains undefined. Uncovering the proteins involved in regulating MV biogenesis is of interest given their role in the dissemination of deleterious cancer traits. MVs shed from drug-resistant cancer cells transfer multidrug resistance (MDR) proteins to drug-sensitive cells and confer the MDR phenotype in a matter of hours. MDR is attributed to the overexpression of ABC transporters, primarily P-glycoprotein and MRP1. Their expression and functionality is dependent on a number of proteins. In particular, FERM domain proteins have been implicated in supporting the functionality of efflux transporters in drug-resistant cells and in recipient cells during intercellular transfer by vesicles. Herein, the most recent research on the proteins involved in MV biogenesis and in the dissemination of MV-mediated MDR are discussed. Attention is drawn to unanswered questions in the literature that may prove to be of benefit in ongoing efforts to improve clinical response to chemotherapy and circumventing MDR.
Awasthi, R, Rathbone, MJ, Hansbro, PM, Bebawy, M & Dua, K 2018, 'Therapeutic prospects of microRNAs in cancer treatment through nanotechnology.', Drug Delivery and Translational Research, vol. 8, no. 1, pp. 97-110.View/Download from: UTS OPUS or Publisher's site
MicroRNAs (miRNAs) represent a new class of diagnostic and prognostic biomarker as well as new therapeutic targets in cancer therapy. miRNAs are gaining significant interest due to extensive advancements in knowledge since their discovery and, more recently, their translational application as therapeutic moieties and targets in the management of disease. miRNAs used in the treatment of cancer would position them as a new class of emerging therapeutic agents. Indeed, numerous candidate miRNAs have been identified as having therapeutic application in the treatment of cancer, but there is still much to learn about how to transform these into effective, patient-compliant, and targeted drug delivery systems. In this mini review, we discuss the utility and potential of nanotechnology in miRNA formulation and delivery with particular emphasis on cancer, including their role in conferring multidrug resistance and metastatic capacity. This review benefits both the formulation and biological scientists in understanding and exploring the new vistas of miRNA delivery using nanotechnology in the cancer clinically.
Awasthi, R, Roseblade, A, Hansbro, PM, Rathbone, MJ, Dua, K & Bebawy, M 2018, 'Nanoparticles in Cancer Treatment: Opportunities and Obstacles', CURRENT DRUG TARGETS, vol. 19, no. 14, pp. 1696-1709.View/Download from: Publisher's site
Chellappan, DK, Ng, ZY, Wong, J-Y, Hsu, A, Wark, P, Hansbro, N, Taylor, J, Panneerselvam, J, Madheswaran, T, Gupta, G, Bebawy, M, Hansbro, PM & Dua, K 2018, 'Immunological axis of curcumin-loaded vesicular drug delivery systems.', Future medicinal chemistry, vol. 10, no. 8, pp. 839-844.View/Download from: UTS OPUS or Publisher's site
Several vesicular systems loaded with curcumin have found their way in the therapeutic applications of several diseases, primarily acting through their immunological pathways. Such systems use particles at a nanoscale range, bringing about their intended use through a range of complex mechanisms. Apart from delivering drug substances into target tissues, these vesicular systems also effectively overcome problems like insolubility and unequal drug distribution. Several mechanisms are explored lately by different workers, and interest over vesicular curcumin has been renewed in the past decade. This commentary discusses several immunological targets in which curcumin is employed in a vesicular form.
De Rubis, G, Krishnan, SR & Bebawy, M 2018, 'Circulating tumor DNA - Current state of play and future perspectives', PHARMACOLOGICAL RESEARCH, vol. 136, pp. 35-44.View/Download from: UTS OPUS or Publisher's site
Dua, K, Awasthi, R, Madan, JR, Chellappan, DK, Nalluri, BN, Gupta, G, Bebawy, M & Hansbro, PM 2018, 'Novel drug delivery approaches in treating pulmonary fibrosis', Panminerva Medica, vol. 60, no. 4, pp. 238-240.View/Download from: Publisher's site
Dua, K, Awasthi, R, Madan, JR, Chellappan, DK, Nalluri, BN, Gupta, G, Bebawy, M & Hansbro, PM 2018, 'Novel drug delivery approaches in treating pulmonary fibrosis', PANMINERVA MEDICA, vol. 60, no. 4, pp. 238-240.View/Download from: UTS OPUS or Publisher's site
Dua, K, de Jesus Andreoli Pinto, T, Chellappan, DK, Gupta, G, Bebawy, M & Hansbro, PM 2018, 'Advancements in nano drug delivery systems: a challenge for biofilms in respiratory diseases', PANMINERVA MEDICA, vol. 60, no. 1, pp. 35-36.View/Download from: UTS OPUS or Publisher's site
Dua, K, Gupta, G, Chellapan, DK, Bebawy, M & Collet, T 2018, 'Nanoparticle-based therapies as a modality in treating wounds and preventing biofilm', Panminerva Medica, vol. 60, no. 4, pp. 237-238.View/Download from: Publisher's site
Dua, K, Gupta, G, Koteswara Rao, N & Bebawy, M 2018, 'Nano-antibiotics: A novel approach in treating P. aeruginosa biofilm infections', Minerva Medica, vol. 109, no. 5, p. 400.View/Download from: Publisher's site
Gupta, G, Bebawy, M, Pinto, TDJA, Chellappan, DK, Mishra, A & Dua, K 2018, 'Role of the tristetraprolin (zinc finger protein 36 homolog) gene in cancer', Critical Reviews in Eukaryotic Gene Expression, vol. 28, no. 3, pp. 217-221.View/Download from: Publisher's site
© 2018 Begell House, Inc. Cancer is a complicated transformational progression that fiercely changes the appearance of cell physiology as well as cells' relations with adjacent tissues. Developing an oncogenic characteristic requires a wide range of modifications in a gene expression at a cellular level. This can be achieved by activation or suppression of the gene regulation pathway in a cell. Tristetraprolin (TTP or ZFP36) associated with the initiation and development of tumors are regulated at the level of mRNA decay, frequently through the activity of AU-rich mRNA-destabilizing elements (AREs) located in their 3′-untranslated regions. TTP is an attractive target for therapeutic use and diagnostic tools due to its characteristic appearance in cancer tissue alone. Thus, the illumination of TTP in diverse types of cancer might deliver additional effective remedies in the coming era for cancer patients. The objective of this review is to familiarize the reader with the TTP proteins, focus on efficient properties that endow them with their effective oncogenic potential, describe their physiological role in cancer cells, and review the unique properties of TT, and of TTP-driven cancer.
Gupta, G, Chellappan, DK, de Jesus Andreoli Pinto, T, Hansbro, PM, Bebawy, M & Dua, K 2018, 'Tumor suppressor role of miR-503.', Panminerva medica, vol. 60, no. 1, pp. 17-24.View/Download from: UTS OPUS or Publisher's site
MicroRNAs (miRNAs) are non-coding RNAs of around 20-25 nucleotides in length with highly conserved characteristics. They moderate post-transcriptional silencing by precisely combining with 3' untranslated regions (UTRs) of target mRNAs at a complementary site. miR‑503, an associate of the "canonical" miRNA-16 family, is expressed in numerous types of tumors such as breast cancer, prostate cancer, lung cancer, colorectal cancer, hepatocellular carcinoma, glioblastoma and several others. There is convincing evidence to show that miR‑503 functions as a tumor suppressor gene through its effects on target genes that regulate cell proliferation, migration, and invasion in tumor cells. In this current assessment, we discuss the biology and tumor suppressor role of miR‑503 in different cancers and elaborate on its mechanism of action.
Ng, ZY, Wong, J-Y, Panneerselvam, J, Madheswaran, T, Kumar, P, Pillay, V, Hsu, A, Hansbro, N, Bebawy, M, Wark, P, Hansbro, P, Dua, K & Chellappan, DK 2018, 'Assessing the potential of liposomes loaded with curcumin as a therapeutic intervention in asthma', COLLOIDS AND SURFACES B-BIOINTERFACES, vol. 172, pp. 51-59.View/Download from: UTS OPUS or Publisher's site
Sunkara, KP, Gupta, G, Hansbro, PM, Dua, K & Bebawy, M 2018, 'Functional relevance of SATB1 in immune regulation and tumorigenesis.', Biomedicine and Pharmacotherapy, vol. 104, pp. 87-93.View/Download from: UTS OPUS or Publisher's site
The Special AT-rich Sequence Binding Protein 1 (SATB1) is a chromatin organiser and transcription factor which regulates numerous cellular processes such as differentiation, proliferation and apoptosis through effects on gene expression. SATB1 undergoes various post-translational modifications, which determine its interaction with co-activators and co-repressors to induce regulation of gene transcription. SATB1 is an identified oncogene, its increased expression is associated with poor prognosis in many cancers. This paper provides a review on SATB1-mediated immune responses and on its target genes in the context of tumorigenesis and tumour progression. Specifically, we discuss the role of SATB1 in tumour immunity, Epithelial to Mesenchymal Transition (EMT), metastasis and multidrug resistance. Therapeutic targeting of aberrant SATB1 may be an important strategy in the treatment of cancer.
Théry, C, Witwer, KW, Aikawa, E, Alcaraz, MJ, Anderson, JD, Andriantsitohaina, R, Antoniou, A, Arab, T, Archer, F, Atkin-Smith, GK, Ayre, DC, Bach, J-M, Bachurski, D, Baharvand, H, Balaj, L, Baldacchino, S, Bauer, NN, Baxter, AA, Bebawy, M, Beckham, C, Bedina Zavec, A, Benmoussa, A, Berardi, AC, Bergese, P, Bielska, E, Blenkiron, C, Bobis-Wozowicz, S, Boilard, E, Boireau, W, Bongiovanni, A, Borràs, FE, Bosch, S, Boulanger, CM, Breakefield, X, Breglio, AM, Brennan, MÁ, Brigstock, DR, Brisson, A, Broekman, ML, Bromberg, JF, Bryl-Górecka, P, Buch, S, Buck, AH, Burger, D, Busatto, S, Buschmann, D, Bussolati, B, Buzás, EI, Byrd, JB, Camussi, G, Carter, DR, Caruso, S, Chamley, LW, Chang, Y-T, Chen, C, Chen, S, Cheng, L, Chin, AR, Clayton, A, Clerici, SP, Cocks, A, Cocucci, E, Coffey, RJ, Cordeiro-da-Silva, A, Couch, Y, Coumans, FA, Coyle, B, Crescitelli, R, Criado, MF, D'Souza-Schorey, C, Das, S, Datta Chaudhuri, A, de Candia, P, De Santana, EF, De Wever, O, Del Portillo, HA, Demaret, T, Deville, S, Devitt, A, Dhondt, B, Di Vizio, D, Dieterich, LC, Dolo, V, Dominguez Rubio, AP, Dominici, M, Dourado, MR, Driedonks, TA, Duarte, FV, Duncan, HM, Eichenberger, RM, Ekström, K, El Andaloussi, S, Elie-Caille, C, Erdbrügger, U, Falcón-Pérez, JM, Fatima, F, Fish, JE, Flores-Bellver, M, Försönits, A, Frelet-Barrand, A, Fricke, F, Fuhrmann, G, Gabrielsson, S, Gámez-Valero, A, Gardiner, C, Gärtner, K, Gaudin, R, Gho, YS, Giebel, B, Gilbert, C, Gimona, M, Giusti, I, Goberdhan, DC, Görgens, A, Gorski, SM, Greening, DW, Gross, JC, Gualerzi, A, Gupta, GN, Gustafson, D, Handberg, A, Haraszti, RA, Harrison, P, Hegyesi, H, Hendrix, A, Hill, AF, Hochberg, FH, Hoffmann, KF, Holder, B, Holthofer, H, Hosseinkhani, B, Hu, G, Huang, Y, Huber, V, Hunt, S, Ibrahim, AG-E, Ikezu, T, Inal, JM, Isin, M, Ivanova, A, Jackson, HK, Jacobsen, S, Jay, SM, Jayachandran, M, Jenster, G, Jiang, L, Johnson, SM, Jones, JC, Jong, A, Jovanovic-Talisman, T, Jung, S, Kalluri, R, Kano, S-I, Kaur, S, Kawamura, Y, Keller, ET, Khamari, D, Khomyakova, E, Khvorova, A, Kierulf, P, Kim, KP, Kislinger, T, Klingeborn, M, Klinke, DJ, Kornek, M, Kosanović, MM, Kovács, ÁF, Krämer-Albers, E-M, Krasemann, S, Krause, M, Kurochkin, IV, Kusuma, GD, Kuypers, S, Laitinen, S, Langevin, SM, Languino, LR, Lannigan, J, Lässer, C, Laurent, LC, Lavieu, G, Lázaro-Ibáñez, E, Le Lay, S & et al. 2018, 'Minimal information for studies of extracellular vesicles 2018 (MISEV2018): a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines.', Journal of Extracellular Vesicles, vol. 7, no. 1, pp. 1535750-1535750.View/Download from: UTS OPUS or Publisher's site
The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles ("MISEV") guidelines for the field in 2014. We now update these "MISEV2014" guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points.
Dua, K, Bebawy, M, Awasthi, R, Tekade, RK, Tekade, M, Gupta, G, De Jesus Andreoli Pinto, T & Hansbro, PM 2017, 'Application of Chitosan and its Derivatives in Nanocarrier Based Pulmonary Drug Delivery Systems.', Pharmaceutical Nanotechnology, vol. 5, no. 4, pp. 243-249.View/Download from: Publisher's site
The respiratory tract as a non-invasive route of drug administration is gaining increasing attention in the present time on achieving both local and the systemic therapeutic effects. Success in achieving pulmonary delivery, requires overcoming barriers including mucociliary clearance and uptake by macrophages. An effective drug delivery system delivers the therapeutically active moieties at the right time and rate to target sites. A major limitation associated with most of the currently available conventional and controlled release drug delivery devices is that not all the drug candidates are well absorbed uniformly locally or systemically.We searched and reviewed the literature focusing on chitosan and chitosan derivative based nanocarrier systems used in pulmonary drug delivery. We focused on the applications of chitosan in the development of nanoparticles for this purpose.Chitosan, a natural linear bio-polyaminosaccharide is central in the development of novel drug delivery systems (NDDS) including nanoparticles for use in the treatment of various respiratory diseases. It achieves this through its unique properties of biodegradability, biocompatibility, mucoadhesivity and its ability to enhance macromolecule permeation across membranes. It also achieves sustained and targeted effects, primary requirements for an effective pulmonary drug delivery system. This review highlights the applications and importance of chitosan with special emphasis on nanotechnology, employed in the management of respiratory diseases such as asthma, Chronic Obstructive Pulmonary Disease (COPD), lung cancer and pulmonary fibrosis.This review will be of interest to both the biological and formulation scientists as it provides a summary on the utility of chitosan in pulmonary drug delivery systems. At present, there are no patented chitosan based controlled release products available for pulmonary drug delivery and so this area has enormous potential in the field of respiratory science.
Jaiswal, R, Johnson, MS, Pokharel, D, Krishnan, SR & Bebawy, M 2017, 'Microparticles shed from multidrug resistant breast cancer cells provide a parallel survival pathway through immune evasion.', BMC Cancer, vol. 17, no. 1, pp. 1-12.View/Download from: UTS OPUS or Publisher's site
BACKGROUND: Breast cancer is the most frequently diagnosed cancer in women. Resident macrophages at distant sites provide a highly responsive and immunologically dynamic innate immune response against foreign infiltrates. Despite extensive characterization of the role of macrophages and other immune cells in malignant tissues, there is very little known about the mechanisms which facilitate metastatic breast cancer spread to distant sites of immunological integrity. The mechanisms by which a key healthy defense mechanism fails to protect distant sites from infiltration by metastatic cells in cancer patients remain undefined. Breast tumors, typical of many tumor types, shed membrane vesicles called microparticles (MPs), ranging in size from 0.1-1 μm in diameter. MPs serve as vectors in the intercellular transfer of functional proteins and nucleic acids and in drug sequestration. In addition, MPs are also emerging to be important players in the evasion of cancer cell immune surveillance. METHODS: A comparative analysis of effects of MPs isolated from human breast cancer cells and non-malignant human brain endothelial cells were examined on THP-1 derived macrophages in vitro. MP-mediated effects on cell phenotype and functionality was assessed by cytokine analysis, cell chemotaxis and phagocytosis, immunolabelling, flow cytometry and confocal imaging. Student's t-test or a one-way analysis of variance (ANOVA) was used for comparison and statistical analysis. RESULTS: In this paper we report on the discovery of a new cellular basis for immune evasion, which is mediated by breast cancer derived MPs. MPs shed from multidrug resistant (MDR) cells were shown to selectively polarize macrophage cells to a functionally incapacitated state and facilitate their engulfment by foreign cells. CONCLUSIONS: We propose this mechanism may serve to physically disrupt the inherent immune response prior to cancer cell colonization whilst releasing mediators required for the recruitment...
Lu, JF, Pokharel, D & Bebawy, M 2017, 'A novel mechanism governing the transcriptional regulation of ABC transporters in MDR cancer cells.', Drug Delivery and Translational Research, vol. 7, no. 2, pp. 276-285.View/Download from: UTS OPUS or Publisher's site
P-glycoprotein (P-gp/ABCB1) and multidrug resistance-associated protein 1 (MRP1/ABCC1) are the main drug efflux transporters associated with treatment failure in cancer. Much attention has been focused on the molecular mechanisms regulating the expression of these transporters as a viable approach for identifying novel drug targets in circumventing cancer multidrug resistance (MDR) clinically. In this paper, we examine the role of miR-326 in the context of its intercellular transfer between cancer cells by extracellular membrane vesicles called microparticles (MPs). We observe that cellular suppression of ABCC1 by miR-326 is modulated by the presence of ABCB1 transcript. Specifically, we show that siRNA silencing of MP-transferred ABCB1 transcript reverses the knockdown effects of miRNA-326 on target MRP1/ABCC1 transcripts. We also demonstrate a dominance of ABCB1 transcripts when co-localized with ABCC1 transcripts, which is consistent with the facilitation of miR-326 function by ABCB1. This study identifies a novel pathway regulating the expression of ABC transporters and positions ABCB1 mRNA as a transcriptional regulator of other members of this superfamily in multidrug resistant cells through its actions on miRNAs.
Pokharel, D, Roseblade, A, Oenarto, V, Lu, J & Bebawy, M 2017, 'Proteins regulating the intercellular transfer and function of P-glycoprotein in multidrug-resistant cancer', ecancermedicalscience, vol. 11.View/Download from: UTS OPUS or Publisher's site
© the authors; Chemotherapy is an essential part of anticancer treatment. However, the overexpression of P-glycoprotein (P-gp) and the subsequent emergence of multidrug resistance (MDR) hampers successful treatment clinically. P-gp is a multidrug efflux transporter that functions to protect cells from xenobiotics by exporting them out from the plasma membrane to the extracellular space. P-gp inhibitors have been developed in an attempt to overcome P-gp-mediated MDR; however, lack of specificity and dose limiting toxicity have limited their effectiveness clinically. Recent studies report on accessory proteins that either directly or indirectly regulate P-gp expression and function and which are necessary for the establishment of the functional phenotype in cancer cells. This review discusses the role of these proteins, some of which have been recently proposed to comprise an interactive complex, and discusses their contribution towards MDR. We also discuss the role of other pathways and proteins in regulating P-gp expression in cells. The potential for these proteins as novel therapeutic targets provides new opportunities to circumvent MDR clinically.
Roseblade, A, Ung, A & Bebawy, M 2017, 'Synthesis and in vitro biological evaluation of thiosulfinate derivatives for the treatment of human multidrug-resistant breast cancer.', Acta Pharmacologica Sinica, vol. 38, no. 10, pp. 1353-1368.View/Download from: UTS OPUS or Publisher's site
Organosulfur compounds derived from Allium vegetables have long been recognized for various therapeutic effects, including anticancer activity. Allicin, one of the main biologically active components of garlic, shows promise as an anticancer agent; however, instability makes it unsuitable for clinical application. The aim of this study was to investigate the effect of stabilized allicin derivatives on human breast cancer cells in vitro. In this study, a total of 22 stabilized thiosulfinate derivatives were synthesized and screened for their in vitro antiproliferative activities against drug-sensitive (MCF-7) and multidrug-resistant (MCF-7/Dx) human adenocarcinoma breast cancer cells. Assays for cell death, apoptosis, cell cycle progression and mitochondrial bioenergetic function were performed. Seven compounds (4b, 7b, 8b, 13b, 14b, 15b and 18b) showed greater antiproliferative activity against MCF-7/Dx cells than allicin. These compounds were also selective towards multidrug-resistant (MDR) cells, a consequence attributed to collateral sensitivity. Among them, 13b exhibited the greatest anticancer activity in both MCF-7/Dx and MCF-7 cells, with IC50 values of 18.54±0.24 and 46.50±1.98 μmol/L, respectively. 13b altered cellular morphology and arrested the cell cycle at the G2/M phase. Additionally, 13b dose-dependently induced apoptosis, and inhibited cellular mitochondrial respiration in cells at rest and under stress. MDR presents a significant obstacle to the successful treatment of cancer clinically. These results demonstrate that thiosulfinate derivatives have potential as novel anticancer agents and may offer new therapeutic strategies for the treatment of chemoresistant cancers.
Taylor, J, Jaiswal, R & Bebawy, M 2017, 'Calcium-calpain Dependent Pathways Regulate Vesiculation in Malignant Breast Cells.', Current Cancer Drug Targets, vol. 17, no. 5, pp. 486-494.View/Download from: UTS OPUS or Publisher's site
Multidrug resistance in cancer (MDR) occurs when tumours become cross-resistant to a range of different anticancer agents. One mechanism by which MDR can be acquired is through cell to cell communication pathways. Membrane-derived microparticles (MPs) are emerging as important signaling molecules in this process. MPs are released from most eukaryotic cells and transfer functional proteins and nucleic acids to recipient cells conferring deleterious traits within the cancer cell population including MDR, metastasis, and angiogenesis. MP formation is known to be dependent on calpain, an intracellular cysteine protease which acts to cleave the cytoskeleton underlying the plasma membrane, resulting in cellular surface blebbing. This study examines differences in vesiculation between malignant and non-malignant cells using high-resolution Atomic Force Microscopy (AFM). We demonstrate that malignant MCF-7 and MCF-7/Dx cells have an intrinsically higher degree of vesiculation at rest when compared to non-malignant human brain endothelial cells (HBEC) and human mammary epithelial cells (MBE-F).. Cellular activation with the calcium ionophore A23187 resulted in an increase in vesiculation in all cell types. We show that calpain-mediated MP biogenesis is the dominant pathway at rest in malignant cells as vesiculation was shown to be inhibited with calpain inhibitor II (ALLM). These results suggest that differences in the biogenic pathways exist in malignant and non-malignant cells and have important implications in defining novel strategies to selectively targeting malignant cells for the circumvention of deleterious traits acquired through intercellular exchange of extracellular vesicles.
Krishnan, SR, Jaiswal, R, Brown, RD, Luk, F & Bebawy, M 2016, 'Multiple myeloma and persistence of drug resistance in the age of novel drugs', International Journal of Oncology, vol. 49, no. 1, pp. 33-50.View/Download from: UTS OPUS or Publisher's site
Multiple myeloma (MM) is a mature B cell
neoplasm that results in multi-organ failure. The median age of
onset, diverse clinical manifestations, heterogeneous survival
rate, clonal evolution, intrinsic and acquired drug resistance
have impact on the therapeutic management of the disease.
Specifically, the emergence of multidrug resistance (MDR)
during the course of treatment contributes significantly to
treatment failure. The introduction of the immunomodulatory
agents and proteasome inhibitors has seen an increase in
overall patient survival, however, for the majority of patients,
relapse remains inevitable with evidence that these agents, like
the conventional chemotherapeutics are also subject to the
development of MDR. Clinical management of patients with
MM is currently compromised by lack of a suitable procedure
to monitor the development of clinical drug resistance in
individual patients. The current MM prognostic measures fail
to pick the clonotypic tumor cells overexpressing drug efflux
pumps, and invasive biopsy is insufficient in detecting sporadic
tumors in the skeletal system. This review summarizes the
challenges associated with treating the complex disease spectrum
of myeloma, with an emphasis on the role of deleterious
multidrug resistant clones orchestrating relapse.
Krishnan, SR, Luk, F, Brown, RD, Suen, H, Kwan, Y & Bebawy, M 2016, 'Isolation of Human CD138(+) Microparticles from the Plasma of Patients with Multiple Myeloma', NEOPLASIA, vol. 18, no. 1, pp. 25-32.View/Download from: UTS OPUS or Publisher's site
Lu, JF, Pokharel, D, Padula, MP & Bebawy, M 2016, 'A novel method to detect translation of membrane proteins following microvesicle intercellular transfer of nucleic acids.', Journal of biochemistry, vol. 160, no. 5, pp. 281-289.View/Download from: UTS OPUS or Publisher's site
Microvesicles (MVs) serve as vectors of nucleic-acid dissemination and are important mediators of intercellular communication. However, the functionality of packaged nucleic acids on recipient cells following transfer of MV-cargo has not been clearly elucidated. This limitation is attributed to a lack of methodology available in assessing protein translation following homotypic intercellular transfer of nucleic-acids. Using surface peptide shaving we have demonstrated that MVs derived from human leukaemic cells transfer functional P-glycoprotein transcripts, conferring drug-efflux capacity to recipient cells. We demonstrate expression of newly synthesized protein using Western blot. Furthermore, we show functionality of translated P-gp protein in recipient cells using Calcein-AM dye exclusion assays on flow cytometry. Newly synthesized 170 kDa P-gp was detected in recipient cells after co-culture with shaven MVs and these proteins were functional, conferring drug-efflux. This is the first demonstration of functionality of transferred nucleic-acids between human homotypic cells as well as the translation of the cancer multidrug-resistance protein in recipient cells following intercellular transfer of its transcript. This study supports the significant role of MV's in the transfer of deleterious traits in cancer populations and describes a new paradigm in mechanisms governing the acquisition of traits in cancer cell populations.
Pokharel, D, Padula, MP, Lu, JF, Jaiswal, R, Djordjevic, SP & Bebawy, M 2016, 'The Role of CD44 and ERM Proteins in Expression and Functionality of P-glycoprotein in Breast Cancer Cells.', Molecules (Basel, Switzerland), vol. 21, no. 3, pp. 1-14.View/Download from: UTS OPUS or Publisher's site
Multidrug resistance (MDR) is often attributed to the over-expression of P-glycoprotein (P-gp), which prevents the accumulation of anticancer drugs within cells by virtue of its active drug efflux capacity. We have previously described the intercellular transfer of P-gp via extracellular vesicles (EVs) and proposed the involvement of a unique protein complex in regulating this process. In this paper, we investigate the role of these mediators in the regulation of P-gp functionality and hence the acquisition of MDR following cell to cell transfer. By sequentially silencing the FERM domain-binding proteins, Ezrin, Radixin and Moesin (ERM), as well as CD44, which we also report a selective packaging in breast cancer derived EVs, we have established a role for these proteins, in particular Radixin and CD44, in influencing the P-gp-mediated MDR in whole cells. We also report for the first time the role of ERM proteins in the vesicular transfer of functional P-gp. Specifically, we demonstrate that intercellular membrane insertion is dependent on Ezrin and Moesin, whilst P-gp functionality is governed by the integrity of all ERM proteins in the recipient cell. This study identifies these candidate proteins as potential new therapeutic targets in circumventing MDR clinically.
Pokharel, D, Wijesinghe, P, Oenarto, V, Lu, JF, Sampson, DD, Kennedy, BF, Wallace, VP & Bebawy, M 2016, 'Deciphering Cell-to-Cell Communication in Acquisition of Cancer Traits: Extracellular Membrane Vesicles Are Regulators of Tissue Biomechanics', OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY, vol. 20, no. 8, pp. 462-469.View/Download from: UTS OPUS or Publisher's site
Gong, J, Jaiswal, R, Dalla, P, Luk, F & Bebawy, M 2015, 'Microparticles in Cancer: A Review of Recent Developments and the Potential for Clinical Application.', Seminars in Cell and Developmental Biology, vol. 40, pp. 35-40.View/Download from: UTS OPUS or Publisher's site
Lee, W-H, Bebawy, M, Loo, C-Y, Luk, F, Mason, RS & Rohanizadeh, R 2015, 'Fabrication of Curcumin Micellar Nanoparticles with Enhanced Anti-Cancer Activity', JOURNAL OF BIOMEDICAL NANOTECHNOLOGY, vol. 11, no. 6, pp. 1093-1105.View/Download from: UTS OPUS or Publisher's site
Murray, M, Hraiki, A, Bebawy, M, Pazderka, C & Rawling, T 2015, 'Anti-tumor activities of lipids and lipid analogues and their development as potential anticancer drugs', PHARMACOLOGY & THERAPEUTICS, vol. 150, pp. 109-128.View/Download from: UTS OPUS or Publisher's site
Roseblade, A, Luk, F, Ung, A & Bebawy, M 2015, 'Targeting microparticle biogenesis: a novel approach to the circumvention of cancer multidrug resistance.', Current Cancer Drug Targets, vol. 15, no. 3, pp. 205-214.View/Download from: UTS OPUS or Publisher's site
Microparticles (MPs) are released from most eukaryotic cells after the vesiculation of the plasma membrane and serve as vectors of long and short-range signaling. MPs derived from multidrug resistant (MDR) cancer cells carry molecular components of the donor cell such as nucleic acids and proteins, and can alter the activity of drug-sensitive recipient cells through the transfer of their cargo. Given the substantial role of MPs in the acquisition and dissemination of MDR, we propose that the inhibition of MP release provides a novel therapeutic approach. This study characterises the effect of a panel of molecules known to act on MP-biosynthetic pathways. We demonstrate a differential effect by these molecules on MP inhibition that appear dependent on the release of intracellular calcium stores following activation with the calcium ionophore A23187. Calpain inhibitor, PD-150606; a selective inhibitor of Rho-associated, coiled-coil containing protein kinase (ROCK), Y-27632; and the vitamin B5 derivative pantethine, inhibited MP release only upon prior activation with A23187. Calpain inhibitor II showed significant inhibition in the absence of cell activation, whereas the vitamin B5 derivatives cystamine dihydrochloride and cysteamine hydrochloride showed no effect on MP inhibition under either condition. In contrast the classical pharmacological inhibitor of MDR, the calcium channel blocker Verapamil, showed an increase in MP formation on resting cells. These results suggest a potential role for calcium in the mechanism of action for PD-150606, Y-27632 and pantethine. These molecules, together with calpain inhibitor II have shown promise as modulators of MP release and warrant consideration as potential candidates for the development of an alternative therapeutic strategy for the prevention of MP-mediated MDR in cancer.
Wright, FA, Bebawy, M & O'Brien, TA 2015, 'An analysis of the therapeutic benefits of genotyping in pediatric hematopoietic stem cell transplantation', FUTURE ONCOLOGY, vol. 11, no. 5, pp. 833-851.View/Download from: UTS OPUS or Publisher's site
Callaghan, R, Luk, F & Bebawy, M 2014, 'Inhibition of the Multidrug Resistance P-Glycoprotein: Time for a Change of Strategy?', Drug Metabolism and Disposition, vol. 42, no. 4, pp. 623-631.View/Download from: UTS OPUS or Publisher's site
P-glycoprotein (P-gp) is a key player in the multidrug-resistant phenotype in cancer. The protein confers resistance by mediating the ATP-dependent efflux of an astonishing array of anticancer drugs. Its broad specificity has been the subject of numerous attempts to inhibit the protein and restore the efficacy of anticancer drugs. The general strategy has been to develop compounds that either compete with anticancer drugs for transport or act as direct inhibitors of P-gp. Despite considerable in vitro success, there are no compounds currently available to 'block' P-gp–mediated resistance in the clinic. The failure may be attributed to toxicity, adverse drug interaction, and numerous pharmacokinetic issues. This review provides a description of several alternative approaches to overcome the activity of P-gp in drug-resistant cells. These include 1) drugs that specifically target resistant cells, 2) novel nanotechnologies to provide high-dose, targeted delivery of anticancer drugs, 3) compounds that interfere with nongenomic transfer of resistance, and 4) approaches to reduce the expression of P-gp within tumors. Such approaches have been developed through the pursuit of greater understanding of resistance mediators such as P-gp, and they show considerable potential for further application.
Gong, J, Luk, F, Jaiswal, R & Bebawy, M 2014, 'Microparticles Mediate the Intercellular Regulation of microRNA-503 and Proline-Rich Tyrosine Kinase 2 to Alter the Migration and Invasion Capacity of Breast Cancer Cells.', Frontiers in Oncology, vol. 4, pp. 1-11.View/Download from: UTS OPUS or Publisher's site
The successful treatment of cancer is hampered by drug resistance and metastasis. While these two obstacles were once considered separately, recent evidence associates resistance with an enhanced metastatic capacity. However, the underlying mechanisms remain undefined. We previously described the intercellular transfer of drug resistance via submicron vesicles called microparticles (MPs). We now propose that MPs derived from drug-resistant cells are also involved in the intercellular transfer of components to enhance the migration and invasion capacity of cells. Thus, MPs may be a conduit between resistance and metastasis. We used microarray analysis to identify regulatory microRNAs (miRNAs), which contribute to the dissemination of metastatic traits. miR-503 was downregulated in recipient cells following co-culture with MPs isolated from drug-resistant cells. miR-503 was inversely associated with metastasis, as demonstrated using wound healing/scratch migration assays and Matrigel(®)-coated transwell invasion assays. Proline-rich tyrosine kinase 2 (PYK2) was upregulated in recipient cells and associated with increased migration and invasion, with these phenotypes being reversed using a pharmacological inhibitor of PYK2 phosphorylation, tyrphostin A9. However, the MP-mediated promotion of metastatic traits was not due to the presence of these effectors in the MP cargo but rather due to down stream effector molecules in these pathways. This is the first demonstration that the role of MPs in trait acquisition extends beyond the direct transfer of vesicle components and also includes transfer of intermediary regulators that induce down stream mediators following transfer to recipient cells. This implicates an expanding role of MPs in cancer pathogenesis.
Haghi, M, Bebawy, M, Colombo, P, forbes, B, Lewis, D, Salama, R, Traini, D & Young, P 2014, 'Towards the bioequivalence of pressurised metered dose inhalers 2. Aerodynamically equivalent particles (with and without glycerol) exhibit different biopharmaceutical profiles in vitro', European Journal of Pharmaceutics and Biopharmaceutics, vol. Online.View/Download from: UTS OPUS or Publisher's site
Two solution-based pressurised metered dose inhaler (pMDI) formulations were prepared such that they delivered aerosols with identical mass median aerodynamic diameters, but contained either beclomethasone dipropionate (BDP) alone (glycerol-free formulation) or BDP and glycerol in a 1:1 mass ratio (glycerol-containing formulation). The two formulations were deposited onto Calu-3 respiratory epithelial cell layers cultured at an air interface. Equivalent drug mass (~1000ng or ~2000ng of the formulation) or equivalent particle number (1000ng of BDP in the glycerol-containing versus 2000ng of BDP in the glycerol-free formulation) were deposited as aerosolised particles on the air interfaced surface of the cell layers. The transfer rate of BDP across the cell layer after deposition of the glycerol-free particles was proportional to the mass deposited. In comparison, the transfer of BDP from the glycerol-containing formulation was independent of the mass deposited, suggesting that the release of BDP is modified in the presence of glycerol. The rate of BDP transfer (and the extent of metabolism) over 2h was faster when delivered in glycerol-free particles, 465.01ng±95.12ng of the total drug (20.99±4.29%; BDP plus active metabolite) transported across the cell layer, compared to 116.17ng±3.07ng (6.07±0.16%) when the equivalent mass of BDP was deposited in glycerol-containing particles. These observations suggest that the presence of glycerol in the maturated aerosol particles may influence the disposition of BDP in the lungs.
Jaiswal, R, Grau, G & Bebawy, M 2014, 'Cellular communication via microparticles: role in transfer of multidrug resistance in cancer', Future Oncology, vol. 10, no. 4, pp. 655-669.View/Download from: UTS OPUS or Publisher's site
Multidrug resistance (MDR) continues to be a major impediment to the successful treatment of cancer. The two efflux transporters, P-glycoprotein (P-gp) and MRP1 are major contributors to cancer MDR clinically. The upregulation of P-gp leading to MDR was initially understood to occur via pre- and post-transcriptional mechanisms only. However, we demonstrated that microparticles mediate the intercellular exchange and trafficking of bioactive material, including functional P-gp and selected modulatory miRNAs. This exchange of P-gp leads to the dissemination of MDR within a cancer cell population. These findings have significant implications in understanding the cellular basis governing the intercellular acquisition of deleterious traits in cancers, serving to substantially advance our understanding of the molecular basis of the emergence of MDR in cancer clinically.
Lee, W-H, Ong, H-X, Loo, C-Y, Traini, D, Young, PM, Luk, F, Bebawy, M & Rohanizadeh, R 2014, 'SYNTHESIS OF CURCUMIN NANOPARTICLES FOR LUNG CANCER THERAPY', JOURNAL OF AEROSOL MEDICINE AND PULMONARY DRUG DELIVERY, vol. 27, no. 4, pp. A17-A17.View/Download from: UTS OPUS
Ong, HX, Benaouda, F, Traini, D, Cipolla, D, Gonda, I, Bebawy, M, forbes, B & Young, P 2014, 'In vitro and ex vivo methods predict the enhanced lung residence time of liposomal ciprofloxacin formulations for nebulisation', European Journal of Pharmaceutics and Biopharmaceutics, vol. online, pp. 1-7.View/Download from: UTS OPUS or Publisher's site
Liposomal ciprofloxacin formulations have been developed with the aim of enhancing lung residence time, thereby reducing the burden of inhaled antimicrobial therapy which requires multiple daily administration due to rapid absorptive clearance of antibiotics from the lungs. However, there is a lack of a predictive methodology available to assess controlled release inhalation delivery systems and their effect on drug disposition. In this study, three ciprofloxacin formulations were evaluated: a liposomal formulation, a solution formulation and a 1:1 combination of the two (mixture formulation). Different methodologies were utilised to study the release profiles of ciprofloxacin from these formulations: (i) membrane diffusion, (ii) air interface Calu-3 cells and (iii) isolated perfused rat lungs. The data from these models were compared to the performance of the formulations in vivo. The solution formulation provided the highest rate of absorptive transport followed by the mixture formulation, with the liposomal formulation providing substantially slower drug release. The rank order of drug release/transport from the different formulations was consistent across the in vitro andex vivo methods, and this was predictive of the profiles in vivo. The use of complimentary in vitro and ex vivo methodologies provided a robust analysis of formulation behaviour, including mechanistic insights, and predicted in vivo pharmacokinetics. ----------------------------------------------------------
Pokharel, D, Padula, MP, Lu, JF, Tacchi, JL, Luk, F, Djordjevic, SP & Bebawy, M 2014, 'Proteome analysis of multidrug-resistant, breast cancer-derived microparticles.', Journal of Extracellular Vesicles, vol. 3, no. 1, pp. 1-10.View/Download from: UTS OPUS or Publisher's site
Cancer multidrug resistance (MDR) occurs when cancer cells evade the cytotoxic actions of chemotherapeutics through the active efflux of drugs from within the cells. Our group have previously demonstrated that multidrug-resistant breast cancer cells spontaneously shed microparticles (MPs) and that these MPs can transfer resistance to drug-responsive cells and confer MDR on those cells in as little as 4 h. Furthermore, we also showed that, unlike MPs derived from leukaemia cells, breast cancer-derived MPs display a tissue selectivity in the transfer of P-glycoprotein (P-gp), transferring the resistance protein only to malignant breast cells. This study aims to define the proteome of breast cancer-derived MPs in order to understand the differences in protein profiles between those shed from drug-resistant versus drug-sensitive breast cancer cells. In doing so, we detail the protein cargo required for the intercellular transfer of MDR to drug-sensitive recipient cells and the factors governing the transfer selectivity to malignant breast cells. We describe the first proteomic analysis of MPs derived from human breast cancer cells using SDS PAGE and liquid chromatography-tandem mass spectrometry (LC/MS/MS), in which we identify 120 unique proteins found only in drug-resistant, breast cancer-derived MPs. Our results demonstrate that the MP-mediated transfer of P-gp to recipient cells occurs alongside CD44; the Ezrin, Radixin and Moesin protein family (ERM); and cytoskeleton motor proteins within the MP cargo.
haghi, M, Traini, D, Postma, DS, Bebawy, M & Young, PM 2013, 'Fluticasone uptake across Calu-3 cells is mediated by salmeterol when deposited as a combination powder inhale', Respirology, vol. 18, no. 8, pp. 1197-1201.View/Download from: UTS OPUS or Publisher's site
BACKGROUND AND OBJECTIVE: We assessed whether co-deposition of a long-acting ß2 -agonist and a corticosteroid affects their respective transport rates across epithelial cells. METHODS: Drug particles were deposited on the air-interface culture of Calu-3 cells using a twin-stage impinger. We compared the transport rate of salmeterol and fluticasone across the epithelial cells using commercially available formulations (Serevent, Flixotide and Seretide). The transepithelial resistance of Calu-3 cells was measured before and after each deposition to monitor epithelial resistance. RESULTS: The codeposition of salmeterol and fluticasone had no significant effect on transport of salmeterol through the cell layer. In contrast, the rate of fluticasone propionate transport in presence of salmeterol xinofoate was significantly lower (0.53 ± 0.20%) compared with the single fluticasone formulation (2.36 ± 0.97%). Furthermore, the resistance of the epithelial cells was significantly increased after salmeterol deposition from both single and combination products. CONCLUSIONS: Our data demonstrate that salmeterol may decrease the permeability of epithelial cells, resulting in slower fluticasone transport across Calu-3 epithelial monolayers. The subsequent increased residence time of fluticasone in the airways could prolong its anti-inflammatory effects.
Jaiswal, R, Luk, F, Dalla, P, Grau, G & Bebawy, M 2013, 'Breast Cancer-Derived Microparticles Display Tissue Selectivity in the Transfer of Resistance Proteins to Cells', PLoS One, vol. 8, no. 4, pp. 1-10.View/Download from: UTS OPUS or Publisher's site
Microparticles (MPs) play a vital role in cell communication by facilitating the horizontal transfer of cargo between cells. Recently, we described a novel "non-genetic" mechanism for the acquisition of multidrug resistance (MDR) in cancer cells by intercellular transfer of functional P-gp, via MPs. MDR is caused by the overexpression of the efflux transporters P-glycoprotein (P-gp) and Multidrug Resistance-Associated Protein 1 (MRP1). These transporters efflux anticancer drugs from resistant cancer cells and maintain sublethal intracellular drug concentrations. By conducting MP transfer experiments, we show that MPs derived from DX breast cancer cells selectively transfer P-gp to malignant MCF-7 breast cells only, in contrast to VLB100 leukaemic cell-derived MPs that transfer P-gp and MRP1 to both malignant and non-malignant cells. The observed transfer selectivity is not the result of membrane restrictions for intercellular exchange, limitations in MP binding to recipient cells or the differential expression of the cytoskeletal protein, Ezrin. CD44 (isoform 10) was found to be selectively present on the breast cancer-derived MPs and not on leukaemic MPs and may contribute to the observed selective transfer of P-gp to malignant breast cells observed. Using the MCF-7 murine tumour xenograft model we demonstrated the stable transfer of P-gp by MPs in vivo, which was found to localize to the tumour core as early as 24 hours post MP exposure and to remain stable for at least 2 weeks. These findings demonstrate a remarkable capacity by MPs to disseminate a stable resistant trait in the absence of any selective pressure.
Lee, W, Loo, CY, Bebawy, M, Luk, F, Mason, R & Rohanizadeh, R 2013, 'Curcumin and its Derivatives: Their Application in Neuropharmacology and Neuroscience in the 21st Century', Current Neuropharmacology, vol. 11, no. 4, pp. 338-378.View/Download from: UTS OPUS or Publisher's site
Curcumin (diferuloylmethane), a polyphenol extracted from the plant Curcuma longa, is widely used in Southeast Asia, China and India in food preparation and for medicinal purposes. Since the second half of the last century, this traditional medicine has attracted the attention of scientists from multiple disciplines to elucidate its pharmacological properties. Of significant interest is curcumins role to treat neurodegenerative diseases including Alzheimers disease (AD), and Parkinsons disease (PD) and malignancy. These diseases all share an inflammatory basis, involving increased cellular reactive oxygen species (ROS) accumulation and oxidative damage to lipids, nucleic acids and proteins. The therapeutic benefits of curcumin for these neurodegenerative diseases appear multifactorial via regulation of transcription factors, cytokines and enzymes associated with (Nuclear factor kappa beta) NF?B activity. This review describes the historical use of curcumin in medicine, its chemistry, stability and biological activities, including curcumin`s anti-cancer, anti-microbial, anti-oxidant, and anti-inflammatory properties. The review further discusses the pharmacology of curcumin and provides new perspectives on its therapeutic potential and limitations. Especially, the review focuses in detail on the effectiveness of curcumin and its mechanism of actions in treating neurodegenerative diseases such as Alzheimers and Parkinsons diseases and brain malignancies
Li, CC, Eaton, SA, Young, PE, Lee, M, Shuttleworth, R, Humphreys, DT, Grau, G, Combes, V, Bebawy, M, Gong, J, Brammah, S, Buckland, ME & Suter, CM 2013, 'Glioma microvesicles carry selectively packaged coding and noncoding RNAs which alter gene expression in recipient cells', RNA Biology, vol. 10, no. 8, pp. 1333-1344.View/Download from: UTS OPUS or Publisher's site
Interactions between glioma cells and their local environment are critical determinants of brain tumor growth, infiltration and neovascularisation. Communication with host cells and stroma via microvesicles represents one pathway by which tumors can modify their surroundings to achieve a tumor-permissive environment. Here we have taken an unbiased approach to identifying RNAs in glioma-derived microvesicles, and explored their potential to regulate gene expression in recipient cells. We find that glioma microvesicles are predominantly of exosomal origin and contain complex populations of coding and noncoding RNAs in proportions that are distinct from those in the cells from which they are derived. Microvesicles show a relative depletion in microRNA compared with their cells of origin, and are enriched in unusual or novel noncoding RNAs, most of which have no known function. Short-term exposure of brain microvascular endothelial cells to glioma microvesicles results in many gene expression changes in the endothelial cells, most of which cannot be explained by direct delivery of transcripts. Our data suggest that the scope of potential actions of tumor-derived microvesicles is much broader and more complex than previously supposed, and highlight a number of new classes of small RNA that remain to be characterized.
Lu, JF, Luk, F, Gong, J, Jaiswal, R, Grau, G & Bebawy, M 2013, 'Microparticles mediate MRP1 intercellular transfer and the re-templating of intrinsic resistance pathways.', Pharmacological Research, vol. 76, pp. 77-83.View/Download from: UTS OPUS or Publisher's site
Multidrug resistance (MDR) is a major impediment to the overall success of chemotherapy in clin-ical oncology. MDR has been primarily attributed by the ATP-dependent transmembrane proteins,P-glycoprotein (P-gp, ABCB1) and Multidrug Resistance-Associated Protein 1 (MRP1, ABCC1). These pro-teins maintain sublethal concentrations of intracellular chemotherapeutics by virtue of their drug effluxcapacity. In this study, we report the acquisition and dissemination of functional MRP1 via microparticle(MP) mediated intercellular transfer. After we showed the transfer and functionality of P-gp in drug sen-sitive recipient cells, we report the transfer and time-dependent functionality of MRP1 in drug sensitiveleukaemia cells following exposure to MPs shed by MRP1-overexpressing MDR cells. We also demonstratea remarkable capacity for MPs shed from cells with a P-gp dominant resistance profile to re-template apre-existing MRP1 dominant profile in recipient cells. These findings have significance in understandingthe molecular basis for tumour dominant phenotypes and introduce potential new strategies and targetsfor the acquisition of MDR and other deleterious traits.
Mamlouk, M, Young, P, Bebawy, M, Haghi, M, Mamlouk, S, Mulay, V & Traini, D 2013, 'Salbutamol Sulfate Absorption Across Calu-3 Bronchial Epithelia Cell Monolayer is Inhibited in the Presence of Common Anionic NSAIDs', Journal Of Asthma, vol. 50, no. 4, pp. 334-341.View/Download from: UTS OPUS or Publisher's site
The aim of this study was to characterize the permeability kinetics of salbutamol sulfate, a commonly used ß2-agonist in the treatment of asthma exacerbation, across Calu-3 respiratory epithelial cell monolayers in the presence of non-steroidal anti-inflammatory drugs (NSAIDs), as they have been implicated to be able to modulate organic cation transporters (OCTs). Methods. Calu-3 cell monolayers were grown in a liquid covered culture (LCC) configuration on 0.33 cm2 Transwell polyester cell culture supports. Monolayers, cultured between 11 and 14 days were evaluated for epithelial resistance, tight junction integrity, and expression of OCT using Western blot analysis. The transport of salbutamol across the monolayer was studied as a function of concentration. Directional transport was investigated by assessing apical-basal (a-b) and basal-apical (b-a) directions. The influence of a non-specific OCT inhibitor (tetraethylammonium, TEA) and three NSAIDs (aspirin, ibuprofen, and indomethacin) on the uptake of salbutamol was studied. Results. The flux of salbutamol sulfate increased with increasing concentration before reaching a plateau, suggesting the involvement of a transport-mediated uptake mechanism. Western blot analysis detected the presence of OCT1-3 and N1 and N2 sub-types, suggesting the presence of functioning transporters. The apparent permeability (Papp) of 0.1 mM salbutamol across the epithelial monolayer displayed directional transport in the a-b direction which was inhibited by ~70% in the presence of TEA, suggesting OCT-mediated uptake. Likewise, the uptake of 0.1 mM salbutamol was decreased in the presence of all the three NSAIDs, supporting a mechanism whereby NSAIDs inhibit absorption of salbutamol across the bronchial epithelium via effects on the OCT transporters. Conclusion. This study demonstrates that NSAIDs influence the uptake kinetics of salbutamol in an in vitro Calu-3 cell system.
Marin, L, Colombo, P, Buttini, F, Bebawy, M, Young, PM & Traini, D 2013, 'MULTIPLE-DOSING OF SIMVASTATIN INHIBITS MUCUS PRODUCTION ON THE CALU-3 AIR INTERFACE CELL MODEL', JOURNAL OF AEROSOL MEDICINE AND PULMONARY DRUG DELIVERY, vol. 26, no. 4, pp. A254-A255.
Marin, L, Traini, D, Bebawy, M, Colombo, P, Buttini, F, Haghi, M, Ong, HX & Young, P 2013, 'Multiple dosing of simvastatin inhibits airway mucus production of epithelial cells: Implications in the treatment of chronic obstructive airway pathologies', European Journal of Pharmaceutics and Biopharmaceutics, vol. 84, no. 3, pp. 566-572.View/Download from: UTS OPUS or Publisher's site
Background Chronic obstructive pulmonary disease (COPD) is characterised by mucus hyper-production. This pathology, together with other inflammatory contributions, leads to airway obstruction and breathing complications. Newer therapeutic approaches are of increased interest, including the use of HMG-CoA reductase inhibitors. Retrospective studies have shown that statins are effective in reducing patient mortality and blood cytokines levels. These findings suggest statins may also provide a new therapeutic approach in COPD treatment. Purpose The aim of the present work was to study the transport of simvastatin (SV) across Calu-3 epithelial cells and to investigate its pharmacological action with respect to reduction in mucus production. Methods Calu-3 cells were grown under liquid covered culture (LCC) conditions for transport studies in order to demonstrate the ability of SV to transport across the monolayer. For mucus detection, cells were grown under air interface culture (AIC) conditions. Samples collected for microscope analysis were stained with alcian blue; images of the stained cell surface were acquired and the mucus was quantified as the RGBB ratio.
Ong, HX, Traini, D, Bebawy, M & Young, P 2013, 'Ciprofloxacin Is Actively Transported across Bronchial Lung Epithelial Cells Using a Calu-3 Air Interface Cell Model.', Antimicrobial agents and chemotherapy, vol. 57, no. 6, pp. 2535-2540.View/Download from: UTS OPUS or Publisher's site
Ciprofloxacin is a well-established broad-spectrum fluoroquinolone antibiotic that penetrates well into the lung tissues; still, the mechanisms of its transepithelial transport are unknown. The contributions of specific transporters, including multidrug efflux transporters, organic cation transporters, and organic anion-transporting polypeptide transporters, to the uptake of ciprofloxacin were investigated in vitro using an air interface bronchial epithelial model. Our results demonstrate that ciprofloxacin is subject to predominantly active influx and a slight efflux component.
Roseblade, AP, Luk, F, Rawling, T, Ung, AT, Grau, G & Bebawy, M 2013, 'Cell-Derived Microparticles: New Targets in the Therapeutic management of disease', Journal of Pharmacy & Pharmaceutical Sciences, vol. 16, no. 2, pp. 238-253.View/Download from: UTS OPUS or Publisher's site
Intercellular communication is essential to maintain vital physiological activities and to regulate the organisms phenotype. There are a number of ways in which cells communicate with one another. This can occur via autocrine signaling, endocrine signaling or by the transfer of molecular mediators across gap junctions. More recently communication via microvesicular shedding has gained important recognition as a significant pathway by which cells can coordinate the spread and dominance of selective traits within a population. Through this communication apparatus, cells can now acquire and secure a survival advantage, particularly in the context of malignant disease. This review aims to highlight some of the functions and implications of microparticles in physiology of various disease states, and present a novel therapeutic strategy through the regulation of microparticle production.
Gong, J, Luk, F, Jaiswal, R, George, AM, Grau, G & Bebawy, M 2013, 'Microparticle drug sequestration provides a parallel pathway in the acquisition of cancer drug resistance', European Journal of Pharmacology, vol. 721, no. 1-3, pp. 116-125.View/Download from: UTS OPUS or Publisher's site
Crowe, A & Bebawy, M 2012, 'ABCB1 (p-glycoprotein) Reduces Bacterial Attachment To Human Gastrointestinal Ls174t Epithelial Cells', European Journal of Pharmacology, vol. 689, no. 1-3, pp. 204-210.View/Download from: UTS OPUS or Publisher's site
The aim of this project was to show elevated P-glycoprotein (P-gp) expression decreasing bacterial association with LS174T human gastrointestinal cells, and that this effect could be reversed upon blocking functional P-gp efflux. Staphylococcus aureus, K
Gong, J, Jaiswal, R, Mathys, J, Combes, V, Grau, GE & Bebawy, M 2012, 'Microparticles and their emerging role in cancer multidrug resistance', Cancer Treatment Reviews, vol. 38, no. 3, pp. 226-234.View/Download from: UTS OPUS or Publisher's site
Drug resistance is a major obstacle to the successful treatment of cancer as tumor cells either fail to reduce in size following chemotherapy or the cancer recurs after an initial response. The phenomenon of multidrug resistance (MDR) is particularly problematic as it involves the simultaneous resistance to numerous chemotherapeutics of different classes. MDR is predominantly attributed to the overexpression of efflux transporters such as P-glycoprotein (P-gp) and the Multidrug Resistance-Associated Protein 1 (MRP1). P-gp and MRP1 are members of the ATP Binding Cassette (ABC) superfamily of transporters and are capable of effluxing many chemotherapeutics out of cancer cells, allowing them to survive the toxic insult. Numerous strategies have been developed over the years to circumvent MDR. Of these, the discovery and implementation of P-gp and MRP1 inhibitors have been most extensively studied. However, these inhibitors have not been able to be used clinically. While research continues in this area, it must also be acknowledged that other avenues must be explored. Recently, the novel `non-genetic acquisition of P-gp-mediated MDR by microparticles (MPs) has been reported. MPs are vesicles 0.11 lm in diameter that are released via plasma membrane blebbing. They are important mediators of inflammation, coagulation and vascular homeostasis. In addition to surface Pgp protein, MPs also carry various nucleic acid species as cargo. This `non-genetic intercellular transfer provides an alternative pathway for the cellular acquisition and dissemination of traits and implicates MPs as important mediators in the spread of MDR and provides a novel pathway for the circumvention of MDR.
Haghi, M, Salama, R, Traini, D, Bebawy, M & Young, P 2012, 'Modification of disodium cromoglycate passage across lung epithelium in vitro via incorporation into polymeric microparticles', The AAPS Journal, vol. 14, no. 1, pp. 79-86.View/Download from: UTS OPUS or Publisher's site
Two microparticle systems containing disodium cromoglycate (DSCG) alone or with polyvinyl alcohol (DSCG/PVA) were produced via spray drying and compared in terms of their physicochemical characteristics, aerosol performance and drug uptake across a pulmonary epithelial cell line (Calu-3), cultured under air interface conditions. The particle size distribution of DSCG and DSCG/PVA were similar, of spherical geometry, amorphous and suitable for inhalation purposes. Aerosolisation studies using a modified twin-stage impinger showed the DSCG/PVA to have greater aerosol performance than that of DSCG alone. Aerosol particles of DSCG and DSCG/PVA were deposited onto the surface of the Calu-3 air interface epithelium monolayer and the drug uptake from apical to basal directions measured over time. Drug uptake was measured across a range of doses to allow comparison of equivalent drug and powder mass deposition. Analysis of the data indicated that the percentage cumulative drug uptake was independent of the mass of powder deposited, but dependent on the formulation. Specifically, with the formulation containing DSCG, the diffusion rate was observed to change with respect to time (indicative of a concentration-dependent diffusion process), whilst DSCG/PVA showed a time-independent drug uptake (suggesting a zero-order depot release).
Haghi, M, Traini, D, Bebawy, M & Paul, YM 2012, 'Deposition, Diffusion and Transport Mechanism of Dry Powder Microparticulate Salbutamol, at the Respiratory Epithelia', Molecular Pharmaceutics, vol. 9, no. 6, pp. 1717-1726.View/Download from: UTS OPUS or Publisher's site
The deposition, dissolution and transport of salbutamol base (SB) and salbutamol sulfate (SS) inhalation powders were investigated using the Calu-3 air interface cell culture model and Franz diffusion cell. Drug uptake by cells was studied with respect to deposited dose, drug solubility and hydrophobicity. Furthermore, the role of active transport via organic cationic transporters (OCTs) was studied. SB and SS were processed to have similar diameters (3.09 ± 0.06 µm and 3.07 ± 0.03 µm, respectively) and were crystalline in nature. Analysis of drug wetting, dissolution and diffusion using a conventional in vitro Franz cell (incorporating a cell culture support Transwell polyester membrane) showed diffusion of SB to be slower than that of SS (98.57 ± 4.23 µg after 4 h for SB compared to 98.57 ± 4.01 µg after 15 min for SS). Such observations suggest dissolution to be the rate-limiting step. In comparison, the percentage transfer rate using the air interface Calu-3 cell model suggested SB transport to be significantly faster than SS transport (92.02 ± 4.47 µg of SB compared to 63.76 ± 8.84 µg of SS transported over 4 h), indicating that passive diffusion through the cell plays a role in transport. Furthermore, analysis of SB and SS transport, over a range of deposited doses, suggested the transport rate in the Franz diffusion cell to be limited by wetting of the particle and dissolution into the medium.
Jaiswal, R, Gong, J, Sambasivam, S, Combes, V, Mathys, J, Davey, R, Grau, GE & Bebawy, M 2012, 'Microparticle-associated nucleic acids mediate trait dominance in cancer', FASEB Journal, vol. 26, no. 1, pp. 420-429.View/Download from: UTS OPUS or Publisher's site
Drug resistance is a major cause of cancer treatment failure, with multidrug resistance (MDR) being the most serious, whereby cancer cells display cross-resistance to structurally and functionally unrelated drugs. MDR is caused by overexpression of the efflux transporters P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1). These transporters act to maintain sublethal intracellular drug concentrations within the cancer cell, making the population treatment unresponsive. Recently, we discovered a novel nongenetic basis to MDR whereby microparticles (MPs) transfer P-gp intercellularly from MDR donor cells to drug-sensitive recipient cells. MPs isolated from MDR leukemia and breast cancer cells were cocultured with their drug-sensitive counterparts. P-gp transfer was assessed by direct immunolabeling, and acquired transcripts and regulatory microRNAs by quantitative real-time PCR. We show that MDR MPs incorporate nucleic acids; MPs change recipient cells' transcriptional environment to reflect donor MDR phenotype, and distinct pathways exist among cancers of different origin that may be dependent on donor cells' ABCB1 overexpression. We demonstrate that this pathway exists for both hematological and nonhematological malignancies. By conferring MDR and "retemplating" the transcriptional landscape of recipient cells, MPs provide a novel pathway, having implications in the dissemination and acquisition of deleterious traits in clinical oncology.-
Jaiswal, R, Luk, F, Gong, J, Mathys, J, Grau, G & Bebawy, M 2012, 'Microparticle Conferred MicroRNA Profiles - Implications In The Transfer And Dominance Of Cancer Traits', Molecular Cancer, vol. 11, pp. 1-13.View/Download from: UTS OPUS or Publisher's site
Background: Microparticles (MPs) are membrane vesicles which are released from normal and malignant cells following a process of budding and detachment from donor cells. MPs contain surface antigens, proteins and genetic material and serve as vectors of intercellular communication. MPs comprise the major source of systemic RNA including microRNA (miRNA), the aberrant expression of which appears to be associated with stage, progression and spread of many cancers. Our previous study showed that MPs carry both transcripts and miRNAs associated with the acquisition of multidrug resistance in cancer.Results: Herein, we expand on our previous finding and demonstrate that MPs carry the transcripts of the membrane vesiculation machinery (floppase and scramblase) as well as nucleic acids encoding the enzymes essential for microRNA biogenesis (Drosha, Dicer and Argonaute). We also demonstrate using microarray miRNA profiling analysis, the selective packaging of miRNAs (miR-1228*, miR-1246, miR-1308, miR-149*, miR-455-3p, miR-638 and miR-923) within the MP cargo upon release from the donor cells.Conclusions: These miRNAs are present in both haematological and non-haematological cancer cells and are involved in pathways implicated in cancer pathogenesis, membrane vesiculation and cascades regulated by ABC transporters. Our recent findings reinforce our earlier reports that MP transfer 're-templates' recipient cells so as to reflect donor cell traits. We now demonstrate that this process is likely to occur via a process of selective packaging of nucleic acid species, including regulatory nucleic acids upon MP vesiculation. These findings have significant implications in understanding the cellular basis governing the intercellular acquisition and dominance of deleterious traits in cancers
Ong, HX, Traini, D, Cipolla, D, Gonda, I, Bebawy, M, Agus, H & Young, P 2012, 'Liposomal Nanoparticles Control The Uptake Of Ciprofloxacin Across Respiratory Epithelia', Pharmaceutical Research, vol. 29, no. 12, pp. 3335-3346.View/Download from: UTS OPUS or Publisher's site
Liposomal ciprofloxacin nanoparticles were developed to overcome the rapid clearance of antibiotics from the lungs. The formulation was evaluated for its release profile using an air interface Calu-3 cell model and further characterised for aerosol perfo
Marin, L, Colombo, P, Bebawy, M, Young, P & Traini, D 2011, 'Chronic obstructive pulmonary disease: patho-physiology, current methods of treatment and the potential for simvastatin in disease management', Expert Opinion on Drug Delivery, vol. 8, no. 9, pp. 1205-1220.View/Download from: UTS OPUS or Publisher's site
Introduction: Chronic Obstructive Pulmonary Disease (COPD) is a severe disease that leads to a non-reversible obstruction of the small airways. The prevalence of this disease is rapidly increasing in developed countries, and in 2020 it has been predicted that this disease will reach the third cause of mortality worldwide. COPD patients do not respond well to current treatment modalities, such as bronchodilators and corticosteroids. Areas covered: This review article focuses on the patho-physiology of COPD, explores current approaches to alleviate and treat the disease, and discusses the potential use of statins for treatment. Specifically, the mechanism of action and metabolism of simvastatin, the most known and studied molecule among the statin family, are critically reviewed. Expert opinion: Various cellular pathways have been implicated in COPD, with alveolar macrophages emerging as pivotal inflammatory mediators in the COPD patho-physiology. Recently, emerging anti-cytokine therapies, such as PDE4 inhibitors and ACE inhibitors, have shown good anti-inflammatory properties that can be useful in COPD treatment. Recently, statins as a drug class have gained much interest with respect to COPD management, following studies which show simvastatin to exert effective anti-inflammatory effects, via inhibition of the mevalonic acid cascade in alveolar macrophages.
Ong, HX, Traini, D, Bebawy, M & Young, P 2011, 'Epithelial profiling of antibiotic controlled release respiratory formulations', Pharmaceutical Research, vol. 28, no. 9, pp. 2327-2338.View/Download from: UTS OPUS or Publisher's site
Release profiles of two ciprofloxacin hydrochloride formulations for the treatment of respiratory infection were evaluated using different in vitro methodologies and characterised for aerosol performance and toxicity. Spray-dried ciprofloxacin and ciprofloxacin spray-dried with polyvinyl alcohol as a controlled release (CR) agent at a 50:50 w/w ratio were formulated and physico-chemically characterised. Aerosol performances were assessed in vitro using a liquid impinger. Drug release was performed using a modified Franz cell and a validated air interface Calu-3-modified twin stage impinger (TSI). Ciprofloxacin toxicity was also established in vitro. Both formulations had a similar size distribution, while CR ciprofloxacin had superior aerosol performance and stability. The release profiles showed the CR formulation to have a higher transport rate compared to ciprofloxacin alone in the cell model. Contrary results were observed using the diffusion cell. Results suggest that the air interface cell model provides a more physiologically relevant model than the modified Franz cell. Toxicity analysis showed that the lung epithelial cells could tolerate a wide range of ciprofloxacin concentrations. This study establishes that the in vitro modified TSI air interface Calu-3 model is capable of evaluating the fate of inhaled powder formulations.
Tran, V, Marks, D, Duke, R, Bebawy, M, Duke, C & Roufogalis, BD 2011, 'Modulation of P-glycoprotein-Mediated Anticancer Drug Accumulation, Cytotoxicity, and ATPase Activity by Flavonoid Interactions', Nutrition and Cancer, vol. 63, no. 3, pp. 435-443.View/Download from: UTS OPUS or Publisher's site
Flavonoids are components of plant foods and of many herbal medicines taken in combination with anticancer drugs. We have examined the potential of flavonoids to affect the accumulation and cytotoxicity of 3 cytotoxic drugs [vinblastine (VLB), daunorubicin (DNR), and colchicine (COL)] that are substrates for the ABC transporter, P-glycoprotein in a vinblastine-resistant T-cell leukemia, CEM/VBL100, that overexpresses P-glycoprotein. The effects of the flavonoids on accumulation and cytotoxicity of these drugs were different depending on the P-gp substrate used. Most of the 30 flavonoids tested decreased DNR accumulation in the VBLresistant, but not sensitive, leukemia cells. By contrast, flavonoids that inhibited DNR accumulation enhanced the accumulation of fluorescently labeled vinblastine. None of these flavonoids affected COL accumulation. The effects of the flavonoids on the cytotoxicities of these drugs paralleled their effects on accumulation; the same flavonoids decreasedDNRcytotoxicity but increased VLB cytotoxicity and had no effect on COL. Verapamil reversed the accumulation deficit and cytotoxicity of all three P-gp substrates. These effects correlated with the effects of flavonoids on P-gp-ATPase activity.
Haghi, M, Traini, D, Jaiswal, R, Gong, J & Bebawy, M 2010, 'Time- and passage-dependent characteristics of a Calu-3 respiratory epithelial cell model', Drug Development And Industrial Pharmacy, vol. 36, no. 10, pp. 1207-1214.View/Download from: UTS OPUS or Publisher's site
Background: Although Standard Protocols For The Study Of Drug Delivery In The Upper Airways Using The Sub-Bronchial Epithelial Cell Line Calu-3 Model, Particularly That Of The Air-Liquid Interface Configuration, Are Readily Available, The Model Remains U
Kota, BP, Tran, V, Allen, J, Bebawy, M & Roufogalis, BD 2010, 'Characterization of PXR mediated P-glycoprotein regulation in intestinal LS174T cells', Pharmacological Research, vol. 62, no. 5, pp. 426-431.View/Download from: UTS OPUS or Publisher's site
Intestinal P-glycoprotein (P-gp) is an important target in drugdrug interactions. Pregnane X receptor (PXR) mediates the induction of intestinal P-gp. The LS174T intestinal cell line has been used in several studies as an in vitro tool to identify the effect of PXR inducers on intestinal P-gp expression. In this study we aimed to further characterize this cell line by focusing on the time dependence of P-gp expression, localization and function in the presence of rifampicin, a P-gp inducer. P-gp protein expression was increased in a time and dose dependent manner following exposure of cells to rifampicin (550M). The induction of P-gp by rifampicin and its inhibition by ketoconazole (an inhibitor of PXR mediated P-gp induction) confirms the suitability of these cells for PXR induction studies. Confocal microscopy showed that P-gp translocated from intracellular compartments to plasma membrane over 7 days in LS174T cells. P-gp function, as established by rhodamine 123 (Rh123) intracellular accumulation, correlated with increasing P-gp expression and plasma membrane localization over this period. Our data demonstrates that LS174T cells provide a suitable in vitro model to test for the effect of PXR inducers/inhibitors on P-gp induction, localization and function over this culture period. This model also has application for the screening of drug candidates for effects on oral bioavailability via effects on the subcellular distribution and trafficking of P-gp.
Bebawy, M & Chetty, M 2009, 'Gender differences in p-glycoprotein expression and function: effects on drug disposition and outcome.', Current Drug Metabolism, vol. 10, no. 4, pp. 322-328.View/Download from: UTS OPUS or Publisher's site
Gender differences in drug concentrations, drug response and toxicity have been attributed to various distinct yet interrelated physiological and molecular mechanisms. Drug transporters and metabolising enzymes play an important role in the xenobiotic cascade and are important regulators of drug disposition at the molecular level. The proposal of a dynamic interplay between drug metabolism and efflux has positioned drug transporters as important mediators of gender disparity in respect to drug disposition and therapeutic response. In examining the effects of gender on drug disposition and response we will specifically direct our focus on the role of the predominant drug transporter, P-glycoprotein. This review focuses on the role of the P-glycoprotein as a molecular mediator of gender differences in both drug exposure and response. Differences in transporter expression and function will be discussed together with the molecular basis for the observed difference in drug exposure between the sexes. Gender differences affecting transporter expression and function at the effect compartment and the effect of this on drug response will also be discussed.
Bebawy, M, Combes, V, Lee, E, Jaiswal, R, Gong, J, Bonhoure, A & Grau, G 2009, 'Membrane microparticles mediate transfer of P-glycoprotein to drug sensitive cancer cells', Leukemia, vol. 23, no. 9, pp. 1643-1649.View/Download from: UTS OPUS or Publisher's site
Multidrug resistance (MDR), a significant impediment to the successful treatment of cancer clinically, has been attributed to the overexpression of P-glycoprotein (P-gp), a plasma membrane multidrug efflux transporter. P-gp maintains sublethal intracellular drug concentrations by virtue of its drug efflux capacity. The cellular regulation of P-gp expression is currently known to occur at either pre- or post-transcriptional levels. In this study, we identify a `non-genetic mechanism whereby microparticles (MPs) serve as vectors in the acquisition and spread of MDR. MPs isolated from drug-resistant cancer cells (VLB100) were co-cultured with drug sensitive cells (CCRFCEM) over a 4 h period to allow for MP binding and P-gp transfer. Presence of P-gp on MPs was established using flow cytometry (FCM) and western blotting. Whole-cell drug accumulation assays using rhodamine 123 and daunorubicin (DNR) were carried out to validate the transfer of functional P-gp after co-culture. We establish that MPs shed in vitro from drug-resistant cancer cells incorporate cell surface P-gp from their donor cells, effectively bind to drug-sensitive recipient cells and transfer functional P-gp to the latter. These findings serve to substantially advance our understanding of the molecular basis for the emergence of MDR in cancer clinically and lead to new treatment strategies which target and inhibit MP mediated transfer of P-gp during the course of treatment.
Bebawy, M, Rasmussen, C, Sambasivam, S & Bao, S 2009, 'Dietary nucleotide supplements in infant formula modify the expression of P-glycoprotein in the intestinal epithelium in vitro.', International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition, vol. 79, no. 5-6, pp. 381-387.View/Download from: Publisher's site
The effect of dietary nucleotides at concentrations found in supplemented infant formula on P-glycoprotein (P-gp) expression in colon cells was examined. We report that P-gp expression in colon cells was significantly decreased in a time- and concentration-dependent manner. When colon cells were co-cultured with lymphocytes, so as to mimic the involvement of gut-associated lymphoid tissue in normal gut pathophysiology, we observed a reversal of this effect with a demonstrated increase in P-gp expression. These findings have important implications on effects of nucleotide exposure on increasing drug bioavailability, reducing the capacity for xenobiotic efflux, and increasing the risk of inflammatory bowel disease in susceptible infants. Future studies are directed at defining both the mechanisms underlying these findings and effects of dietary nucleotide supplementation in vivo.
Bebawy, M, Rasmussen, CB, Sambasivam, S & Bao, S 2009, 'Dietary nucleotide supplements in infant formula modify the expression of P-glycoprotein in the intestinal epithelium in vitro', International Journal For Vitamin And Nutrition Research, vol. 79, no. 5-6, pp. 381-387.View/Download from: UTS OPUS or Publisher's site
The Effect Of Dietary Nucleotides At Concentrations Found In Supplemented Infant Formula On P-Glycoprotein (P-Gp) Expression In Colon Cells Was Examined. We Report That P-Gp Expression In Colon Cells Was Significantly Decreased In A Time- And Concentrati
Bebawy, M & Chetty, M 2008, 'Differential pharmacological regulation of drug efflux and pharmacoresistant schizophrenia', Bioessays, vol. 30, no. 2, pp. 183-188.View/Download from: UTS OPUS or Publisher's site
Pharmacoresistant schizophrenia is a significant impediment to the successful management of the disease. The expression and function of P-glycoprotein (P-gp) has recently been implicated in this phenomenon. P-gp is a multidrug efflux transporter that prevents drug substrates from crossing the bloodbrain barrier (BBB). Although the direct interaction between individual antipsychotic agents and P-gp has been demonstrated, the effect of antipsychotic drug combinations used in disease management on P-gp transport function remains to be elucidated. This could have important clinical implications in some individuals as dosage adjustments based on plasma drug concentration changes may not always be appropriate if drugdrug interactions and the resulting changes in drug concentration in the brain are not considered. This paper introduces the potential impact that combination antipsychotic therapy may have on P-gp function at the BBB and discusses the consequences of this in the prevention and circumvention of unfavourable therapeutic response in schizophrenic disorders.
Bebawy, M & Sze, DM 2008, 'Targeting P-glycoprotein for effective oral anti-cancer chemotherapeutics', Current Cancer Drug Targets, vol. 8, no. 1, pp. 47-52.View/Download from: UTS OPUS or Publisher's site
Oral anticancer drug treatment represents a significant change to current oncology practice. Support for oral anticancer treatment is driven by issues of pharmacoeconomics, accommodating the need for protracted drug administration for many emerging cytostatic therapies, response to patient preference and in improving patient quality of life. Much focus has concentrated on defining the cellular mechanisms underlying the pharmacokinetic limitations associated with the oral route of administration. However, the potential effects of oral anticancer drugs on gut associated host mediated immunity have been overlooked. Given that the immune system is central for tumour rejection, an assessment of the potential effects oral anticancer drugs may have at this level, and the impact of this on the treatment of gastrointestinal malignancy is of significant clinical importance. P-glycoprotein is a multidrug transporter that contributes to the reduced bioavailability of many orally administered medications. P-glycoprotein achieves this by virtue of its drug efflux capacity at the level of the gut epithelia. P-glycoprotein is also notorious for contributing to the multidrug resistance phenotype observed in many drug refractory human cancers. Likewise, this drug transporter serves a role in the cells of the immune system; particularly in dendritic cell maturation and function. This multifaceted involvement in drug disposition, cancer drug resistance and regulation of the immune response makes P-glycoprotein an attractive target for the optimization of oral anticancer drug treatment strategies.
Huang, TH, Bebawy, M, Tran, V & Roufogalis, BD 2007, 'Specific reversal of multidrug resistance to colchicine in CEM/VLB100 cells by Gynostemma pentaphyllum extract', Phytomedicine, vol. 14, no. 12, pp. 830-839.View/Download from: UTS OPUS or Publisher's site
P-glycoprotein (P-gp)-mediated multiple drug resistance (MDR) is perhaps the most thoroughly studied cellular mechanism of cytotoxic drug resistance. Its efflux function can be circumvented by a wide range of pharmacological agents in vitro and in vivo. Most of these agents are pharmaceuticals used clinically for conditions other than cancer. However, their use in alleviating MDR is limited because the concentrations required for inhibition of the pump surpass their dose-limiting toxicity. The aim of this research is to study the role of gypenosides, isolated from Gynostemma pentaphyllum, as modulators of P-gp-mediated MDR in tumor cells, at both cellular and plasma membrane level. In the presence of total gypenoside preparation (0.1 mg/ml), an approximately 15-fold reversal of colchicine (COL) resistance was observed in P-gp-overexpressed CEM/VLB100 cells. However, the gypenoside sample showed no reversal effect in cells treated with vinblastine and taxol. A purified gypenoside sample (gypenoside fraction 100) exhibited even more significant reversal of COL resistance (42-fold) in the CEM/VLB100 cells.
Holland, M, Panetta, J, Hoskins, J, Bebawy, M, Roufogalis, BD, Allen, JD & Arnold, J 2006, 'The effects of cannabinoids on P-glycoprotein transport and expression in multidrug resistant cells', Biochemical Pharmacology, vol. 71, no. 8, pp. 1146-1154.View/Download from: UTS OPUS or Publisher's site
Cannabis Is The Most Widely Used Illicit Drug In The World. Cannabinoids Are Used Therapeutically By Some Patients As They Have Analgesic, Anti-Emetic And Appetite Stimulant Properties Which Palliate Adverse Symptoms. Use Of These Agents In An Oncology S
Fu, D, Bebawy, M, Kable, E & Roufogalis, BD 2004, 'Dynamic and intracellular trafficking of P-glycoprotein-EGFP fusion protein: Implications in multidrug resistance in cancer', International Journal of Cancer, vol. 109, no. 2, pp. 174-181.View/Download from: UTS OPUS or Publisher's site
In our present study, a P-glycoprotein-EGFP (P-gp-EGFP) fusion plasmid was constructed and functionally expressed in HeLa cells to investigate the intracellular localization and trafficking of P-glycoprotein (P-gp). Using immunocytochemistry and fluorescent confocal microscopy techniques, colocalization studies showed that after transfection, P-gp- EGFP was progressively transported from the endoplasmic reticulum (ER) to the Golgi and finally to the plasma membrane within 1248 hr. The degree of intracellular accumulation of daunorubicin was related to the particular localization of P-gp-EGFP. Significant daunorubicin accumulation occurred in transfected cells when P-gp-EGFP was localized predominantly within the ER, and accumulation remained high when P-gp-EGFP was mainly localized in the Golgi. However, there was little or no intracellular accumulation of daunorubicin when P-gp-EGFP was localized predominantly on the plasma membrane. Blocking the intracellular trafficking of P-gp-EGFP with brefeldin A (BFA) and monensin resulted in inhibition of traffic of P-gp-EGFP and retention of P-gp-EGFP intracellularly. Intracellular accumulation of daunorubicin also increased in the presence of BFA or monensin. Our study shows that P-gp-EGFP can be used to define the dynamics of P-gp traffic in a transient expression system, and demonstrates that localization of P-gp on the plasma membrane is associated with the highest level of resistance to daunorubicin accumulation in cells. Modulation of intracellular localization of P-gp with agents designed to selectively modify its traffic may provide a new strategy for overcoming multidrug resistance in cancer cells.
Pajic, M, Bebawy, M, Hoskins, J, Roufogalis, BD & Rivory, L 2004, 'Effect of short-term morphine exposure on P-glycoprotein expression and activity in cancer cell lines', Oncology Reports, vol. 11, no. 5, pp. 1091-1095.View/Download from: UTS OPUS
Amultidrug Resistance (Mdr) Is A Common Problem In Various Types Of Cancer. One Important Factor In The Development Of Mdr Is Overexpression Of P-Glycoprotein, Encoded By The Mdr1 Gene. Morphine Is The Opioid Of Choice For Moderate To Severe Cancer Pain,
Bebawy, M, Morris, M & Roufogalis, BD 2001, 'Selective modulation of P-glycoprotein-mediated drug resistance', British Journal Of Cancer, vol. 85, no. 12, pp. 1998-2003.View/Download from: UTS OPUS or Publisher's site
Multidrug resistance associated with the overexpression of the multidrug transporter P-glycoprotein is a serious impediment to successful cancer treatment. We found that verapamil reversed resistance of CEM/VLB100 cells to vinblastine and fluorescein-colchicine, but not to colchicine. Chlorpromazine reversed resistance to vinblastine but not to fluorescein-colchicine, and it increased resistance to colchicine. Initial influx rates of fluorescein-colchicine were similar in resistant and parental cells, whereas vinblastine uptake was about 10- fold lower in the resistant cells. These results provide indirect evidence that fluorescein-colchicine is transported from the inner leaflet of the membrane and vinblastine from the outer membrane leaflet. Verapamil inhibited luorescein-colchicine transport in inside-out vesicles made from resistant cells, whilst chlorpromazine was found to activate the transport of fluorescein-colchicine. The chlorpromazine-induced activation of fluorescein-colchicine transport was temperature-dependent and may reflect its interaction with phospholipids localised in the same bilayer leaflet. Conversely, chlorpromazine localisation in this leaflet may be responsible for its allosteric inhibition of vinblastine transport from the opposing membrane leaflet. The proposed relationship between the selectivity of modulation of P-glycoprotein and the membrane localisation of the cytotoxic drug substrates and modulators may have important implications in the rational design of regimes for the circumvention of multidrug resistance clinically.
Bebawy, M, Morris, M & Roufogalis, BD 1999, 'A continuous fluorescence assay for the study of P-glycoprotein-mediated drug efflux using inside-out membrane vesicles', Analytical Biochemistry, vol. 268, no. 2, pp. 270-277.View/Download from: UTS OPUS or Publisher's site
A fluorimetric procedure for assaying the transport activity of P-glycoprotein (P-gp) using a membrane vesicle model has been developed. In this assay methylene blue is incorporated into inside-out vesicles prepared from human acute lymphoblastic leukemic cells resistant to 100 ng z ml21 vinblastine (VBL100) and their sensitive controls. The fluorescence of a fluorescent derivative of colchicine (fluoresceincolchicine) is quenched as the probe is transported across the vesicle membrane. The fluoresceincolchicine transport was found to be dependent on the presence of P-glycoprotein, required ATP, and was inhibited by vanadate and the reversal agent, verapamil, in a dose-dependent manner. Furthermore, the transport was competed against by the P-gp substrates, vinblastine and methotrexate. The transport of fluoresceincolchicine by P-gp was found to be cooperative (n 5 1.23).
Bebawy, M, Howes, LG, Karantanis, E & Morris, DL 1995, 'The effects of taxotere in combination with lipiodol on human colorectal cell lines', Regional Cancer Treatment, vol. 8, no. 3-4, pp. 185-188.
The in vitro effects of taxotere alone or taxotere in combination with lipiodol were studied in 6 colorectal cancer cell lines- C146, C170, LoVo, LIM1215, LIM2463 and LIM2412. Taxotere alone significantly inhibited the growth of all 6 cell lines, but in 2 of the cell lines (C170 and LIM2463) the inhibition of growth was small. The addition of lipiodol (20% v/v) to taxotere prevented the cytotoxic effects of taxotere in three cell lines (LoVo, LIM1215 and LIM2463) and in some instances appeared to result in a stimulation of cell proliferation. In the remaining cell lines the addition of lipiodol to taxotere had little effect. Lipiodol alone produced a significant stimulation of the proliferation of all cell lines at a concentration of 75% v/v. The use of lipiodol as a vehicle for targeting taxotere therapy to hepatic metastases may be associated with a reduction in cytotoxic activity in some tumours.
Jaiswal, R, Pokharel, D & Bebawy, M 2016, 'The role of microvesicles on immune function in response to cancer', CANCER RESEARCH, AACR 107th Annual Meeting on Bioinformatics and Systems Biology, AMER ASSOC CANCER RESEARCH, New Orleans, LA.View/Download from: UTS OPUS or Publisher's site
Taylor, J, Jaiswal, R & Bebawy, M 2016, 'Abstract 249: Breast cancer cell vesiculation is driven by calpain: implications in cancer therapy', Experimental and Molecular Therapeutics, Proceedings: AACR 107th Annual Meeting 2016; April 16-20, 2016; New Orleans, LA, American Association for Cancer Research.View/Download from: UTS OPUS or Publisher's site
Bebawy, M, Lu, J-F, Pokharel, D & Luk, F 2015, 'Functional translation of total RNA packaged in microparticles shed from multidrug resistant cancer cells', Clin Cancer Res February 15, 2015 21; B19, AACR Precision Medicine Series: Drug Sensitivity and Resistance: Improving Cancer Therapy; June 18-21, 2014; Orlando, FL.View/Download from: UTS OPUS or Publisher's site
Gong, J, Luk, F, Jaiswal, R & Bebawy, M 2014, 'Microparticles derived from drug-resistant cells regulate miR-503 and PYK2 to promote migration and invasion in breast cancer', AACR Precision Medicine Series: Drug Sensitivity and Resistance: Improving Cancer Therapy, Clinical Cancer Research, Orlando, FL.View/Download from: UTS OPUS or Publisher's site
Introduction: Drug resistance and metastatic spread are two of the most malicious aspects of cancer progression. Microparticles (MPs) have previously been implicated in the spread of these phenotypes independently. We now demonstrate that these two characteristics are linked, with the MP-mediated acquisition of drug resistance correlating with the emergence of an enhanced metastatic capacity. In this way, MPs serve as a conduit between drug resistance and metastasis. Therefore, addressing the impact of MPs may be a means of managing both of these deleterious aspects simultaneously. This makes MPs a significant and viable target in the management of cancer.
Krishnan, RS, Luk, F, Brown, R-D, Kwan, Y-L & Bebawy, M 2015, 'A novel personalized therapeutic management in multiple myeloma', Clin Cancer Res February 15, 2015 21; B52, AACR Precision Medicine Series: Drug Sensitivity and Resistance: Improving Cancer Therapy; June 18-21, 2014; Orlando, FL, AACR, Orlando, USA, pp. B52-B52.View/Download from: UTS OPUS or Publisher's site
Introduction: Multiple Myeloma (MM) is an incurable hematological malignancy affecting plasma cells marked by highly heterogeneous survival rate. Relapse is a significant impediment to the successful treatment of MM clinically. One of the main causes for relapse is drug resistance to cancer chemotherapy. Currently risk stratification to MM sub -groups and categorization of complete response to therapy are assessed based on molecular, cytogenetic markers using bone marrow biopsy as available systemic markers are incompetent in this regard. We are exploring the clinical significance of our recent in vitro and in vivo findings of a novel non-genetic basis to MDR whereby tiny vesicles called microparticles (MPs) shed from cancer cell's surface transfer MDR phenotype intercellularly. MP isolated from the blood of patients who suffer from Multiple Myeloma will be phenotyped for resistance, adhesion and dissemination markers and assessed whether these characteristics are predictive of treatment outcome.
Krishnan, SR, Bebawy, M, Luk, F, Brown, RD & Kwan, YL 2015, 'Abstract B45: Multiple myeloma: A novel tailor-made therapeutic management.', Myeloma, Abstracts: AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; September 20-23, 2014; Philadelphia, PA, American Association for Cancer Research.View/Download from: UTS OPUS or Publisher's site
Rajeev Krishnan, S, Bebawy, M, Brown, RD, Luk, F & Kwan, Y 2015, 'Microparticles as novel prognostic markers in multiple myeloma', Cancer Research, AACR 106th Annual Meeting 2015, American Association for Cancer Research, Philadelphia, USA, pp. 5306-5306.View/Download from: UTS OPUS or Publisher's site
Introduction: Multiple Myeloma (MM) is an incurable hematological malignancy affecting plasma cells marked by highly heterogeneous survival rates and confinement of the disease to bone marrow (BM). Relapse is a significant impediment in the clinical setting and the development of multidrug resistance (MDR) to therapy is the main cause of relapse. Currently, risk stratification to MM sub-groups and categorization of complete response to therapy are established on molecular and cytogenetic markers using bone marrow biopsies. We are exploring the clinical significance of plasma cell derived microparticles as a novel prognostic indicator in MM. Materials and Methods: We have analysed 79 de-identified MM patients and 24 normal subjects. Platelet free plasma was centrifuged and plasma cell derived MPs were identified and quantified by flow cytometry using Annexin V450, CD138 APC, anti-P-glycoprotein (P-gp)-FITC (17F9) in BD TruCount tubes. Platelet derived MPs were excluded from the analysis using CD41a-PE. All patient samples were compared to age-matched healthy volunteers. Western blot analysis was conducted on MP lysates probing for the presence of Lung-Resistance related Protein (LRP) and P-glycoprotein (P-gp). Morphology and the size of MP fraction from MM patients were investigated using scanning electron micrographs Results: The number of systemic MPs and CD138+MPs were found to be significantly higher in MM patient samples compared to the healthy volunteers. MDR markers (LRP & P-gp) were expressed on systemic MPs from relapsing MM patients. MPs from patients were spherical in shape and had smooth surface consistent with those isolated from the MM cell line OPM2.
Pozzoli, M, Sonvico, F, Ong, HX, Traini, D, Bebawy, M & Young, P 2014, 'Optimization of RPMI 2650 Cells as a Model for Nasal Mucosa', Respiratory Drug Delivery 2014, Virginia Commonwealth University, Fajardo, Puerto Rico, pp. 739-742.View/Download from: UTS OPUS
Bebway, M, Jaiswal, R, Gong, J & Grau, G 2013, 'Treatment of Cancer Drug Resistance: microparticle-mediatedresistance', Proceedings of conference on Mechanism-Based Development of Natural Products for Human Health, Journal of Pharmacy & Pharmaceutical Sciences, pp. 125-176.
Haghi, M, Traini, D, Bebawy, M & Young, P 2013, 'Uptake of Salmeterol Xinafoate and Fluticasone Propionate from Single and Combination Dry Powder Inhalers After Deposition on Calu-3 Respiratory Epithelia.', Respiratory Drug Delivery Europe 2013, Respiratory Drug Delivery, Berlin, Germany, pp. 445-448.
Lee, W, Ong, H, Loo, J, Traini, D, Young, PM, Luk, F, Bebawy, M & Rohanizadeh, R 2013, 'Formulation of curcumin nanoparticles for lung cancer therapy', Drug Delivery to the Lungs, Aerosol Society, Edinburgh, pp. 165-168.
Ong, HX, Cipolla, DC, Gonda, I, Traini, D, Bebawy, M, Agus, H & Young, PM 2012, 'Inhaled Liposomal Ciprofloxacin Nanoparticles Control the Release of Antibiotic at the Bronchial Epithelia', Respiratory Drug Delivery Proceedings Vol 3, Respiratory Drug Delivery, Virginia Commonwealth University, Pheonix, USA, pp. 527-530.View/Download from: UTS OPUS
The cycle of respiratory tract infection (RTI) and inflammation in patients with chronic obstructive
lung diseases, such as cystic fibrosis (CF), periodically develops into exacerbations, where
chronic colonization of the airway by bacteria causes severe decline in lung function, leading
to increased hospitalization and high mortality rates (1, 2). Current antibiotic inhalation treatments
approved for the management of chronic airway infections in cystic fibrosis are limited
to tobramycin (TOBI®) and more recently, aztreonam (Cayston®). A major drawback to these
localized treatments of RTIs is the rapid absorption and clearance of antibiotics from the lungs
requiring multiple daily inhalations of high concentration antibiotic solutions. Hence, liposomal
ciprofloxacin nanoparticles were developed to prolong lung residence time of the antibiotics, with
the view to enhance antimicrobial activity and reduce the burden of therapy for the patients and
their relatives who often have to assist them. Although in vivo studies with aerosolized delivery
of liposomal ciprofloxacin have previously been performed on human and animal subjects, in vitro
cell models may be better suited to study the transport, interactions of drugs and carrier systems,
and drug localization within and on the airway cell epithelium at a molecular level. Therefore, the
aim of this study was to investigate the newly developed system allowing nebulized liposomal ciprofloxacin
to be delivered directly to the bronchial epithelial surface in an established air interface
Calu-3 cell model.
Haghi, M, Traini, D, Bebawy, M & Young, P 2011, 'Comparison of albuterol sulphate and base dry powder particulate deposition using the Calu-3 lung epithelial model', RDD Europe 2011, Respiratory Drug Delivery, Virginia Commonwealth University, Germany, pp. 519-522.View/Download from: UTS OPUS
To effectively predict the fate of formulated inhalation compounds delivered to the lung, a model of the airway epithelium should reflect drug permeability and transport characteristics in vivo. Most cell-based system established for this purpose, study drug transport using wet models and thus do not necessarily represent in vivo conditions. Recently, air-interface models have been established that increase the relevance of in vitro transport studies to the in vivo state. The aim of our study was to elucidate the dissolution and diffusion process of deposited dry drug particulates (albuterol) after aerosolization onto the epithelial surface and compare these to conventional in vitro `glass models. Two forms of albuterol were investigated (albuterol base and albuterol sulphate), to evaluate the effects of lipophilicity and aqueous solubility on the mechanism of transport.
Ong, HX, Traini, D, Bebawy, M & Young, P 2011, 'Cellular release profiling of controlled release dry powder pulmonary formulation', RDD Europe 2011, Respiratory Drug Delivery, Virginia Commonwealth University, Germany, pp. 1-4.View/Download from: UTS OPUS
Respiratory tract infections (RTI), such as pneumonia, are very common and their treatments represent the largest proportion of the antibacterial market. Rapid pulmonary antibiotic absorption and clearance suggest controlled release (CR) inhaled antibiotic formulations would be beneficial for the treatment of chronic infections. To date, there is no pharmacopoeia methodology for the evaluation of in vitro drug release of respiratory formulations. This could be attributed to the lack of predictability and correlation between available in vitro and in vivo models for pulmonary drugs. Hence, to effectively predict the pharmacokinetics of drugs delivered to the lungs, a model of the airway epithelium is proposed to reflect the transport characteristics in vivo. Ciprofloxacin was chosen as a model drug.
Haghi, M, Young, P, Traini, D & Bebawy, M 2010, 'Characterization of P-gp Expression and Function vs. Time and Passage in the Calu-3 Air-Interface Model for Drug Delivery to the Lung', Proceedings of Respiratory Drug Delivery 2010, Respiratory Drug Delivery 2010, Davis Healthcare Int', Orlando, Florida, pp. 875-878.View/Download from: UTS OPUS
Calu-3, a sub-bronchial epithelial cell line, cultured at the air-interfaced, has been shown to be a very reliable model for the in vitro investigation of inhalation drug delivery to the upper airways. It has been found to be superior with respect to morphology and function when compared to the liquid covered culture model (1, 2), but the Calu-3 air-interface model has not been fully investigated for P-glycoprotein (P-gp) expression (3, 4) a parameter that could influence predicted drug delivery in the lung. P-gp is a plasma membrane drug transporter, actively involved in `carrying a wide range of structurally and functionally unrelated drugs out of cells (5). P-gp has been shown to interact with some drugs routinely used in respiratory therapy (1). Another factor that may affect drug transport across the epithelium is the presence of mucus; which, in healthy lungs, aids mucociliary clearance of deposited particulate matter, acts as an antibacterial substance and prevents loss of excessive fluid from the airway due to evaporation (6). The aim of this investigation was to characterize mucus secretion and cell surface P-gp expression and function in the Calu-3 air-interface model.
Bebawy, M, Karantanis, E, Howes, L & Morris, DL 1993, 'Effects of taxotere in combination with lipiodol on C146 in vitro', Effects of taxotere in combination with lipiodol on C146 in vitro, Queensland Institute Medical Research, Australian and New Zealand Journal of Surgery, Brisbane, pp. 363-363.
- Prof Tracey O'Brien, Kids Cancer Centre and Head of Blood and Marrow Transplant Program Prince of Wales Hospital.
- Prof Joy Ho, Prof Douglas Joshua and Dr Christian Bryant (RPA Institute of Haematology)
- Prof Judith Trotman and Dr Nicole Wong Doo (Concord Hosital Clinical Haematology)
- Dr Kliman and Dr Kent, St Vincents Hospital Clinical Haematology
- Dr Shir-jing Ho (St George Hospital Clinical Harmatology)
- Dr Ali Khalil (POW Clinical Haematology)
- Prof Greg Monteith University of Queensland
- HSA Biobank
- NSW Health Pathology
- Prof Bogdan Gabrys (Director of Advanced Analytics, UTS
- Herve Harvard (Director Rapido, UTS)
- A/Prof Majid Warkiani (Biomedical Engineering UTS)
- A/Prof De Abreu Lourenco (CHERE, UTS)
- Prof Michael Wallach (Director SPARK Sydney)