Ovarian cancer claims the lives of more than 150000 women worldwide annually. One of the contributors to this high mortality is resistance to cisplatin chemotherapy. Resistance to cisplatin is multifactorial involving various networks and tiers of regulation and is not completely understood yet. Among the regulatory molecules in the body, microRNAs have a prominent role in physiological and pathological conditions. Extracellular Vesicle (EV) communication between cells could also play a noteworthy role in cisplatin resistance. The main aim was to identify microRNAs involved in cisplatin resistance in ovarian cancers whose role in this aspect has not been documented yet and to ascertain and validate possible targets. MicroRNAs exhibiting differential levels of expression in sensitive and resistant ovarian cancer cell lines were identified. Gain or loss of function experiments in cell lines validated their involvement in cisplatin resistance; possible targets were confirmed by transient knockdown experiments in ovarian cancer cell lines. miR-21* and miR-31 functionally increased cisplatin resistance in ovarian cancer cells; NAV3 and KCNMA were validated as their respective targets and shown to modulate cisplatin resistance in ovarian cancer cell lines. A second aim was to explore the role of EVs in cisplatin resistance – to investigate if cisplatin resistance could be transferred between cell lines and to investigate the consequences of preventing EV uptake within a population of cisplatin treated cells. EVs extracted from a cisplatin resistant cell line were transferred onto a cisplatin sensitive cell line; results showed that these EVs could increase cisplatin resistance in the recipient cell line. The response of ovarian cancer cells to cisplatin was analysed following prevention of EV uptake by using heparin, amiloride or dynasore - known inhibitors of EV uptake; results indicate that inhibition of EV uptake increases cisplatin sensitivity significantly. These results open up future avenues for research regarding the role of microRNAs and EVs in cisplatin resistance with possible therapeutic potential.
Permanent link to this resource: https://doi.org/10.24384/bhrw-wn75
Samuel, Priya
Supervisors: Brooks, Susan; Carter, David
Faculty of Health and Life SciencesDepartment of Biological and Medical Sciences
Year: 2016
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