Introduction: Ovarian cancer (OC) is the deadliest gynecological disease in North America, with a 5-year survival rate of 45%. High grade serous ovarian cancer (HGSC), the most common histotype of epithelial OC, is a disease of high inter- and intra-tumour heterogeneity with few recurring mutations other than TP53. Despite this heterogeneity, all tumor cells display high levels of aneuploidy, making this an attractive feature for new therapeutics. We have shown that downregulation of the small GTPase Ran decreases cell proliferation and promotes apoptosis of aneuploid cells, with little effect on normal diploid cells. Thus, we have developed a series of novel small-molecule inhibitors of Ran and have identified a series of inhibitors that disrupt aneuploid HGSOC cell line proliferation without affecting normal diploid cells. Going forward towards more pre-clinical assays, this study aims to test various Ran GTPase inhibitors on ex vivo live human OC samples using microfluidic models.

Methods: Micro-dissected tumors (MDTs) of OC patient samples were loaded into microfluidic devices and treated with selected Ran GTPase inhibitors at various concentrations and different time-points. The MDTs were then formalin-fixed, paraffin embedded and analyzed via immunofluorescence for markers of proliferation (KI67) and apoptosis (cleaved-caspase 3 (CC3)).

Results: We compared the tumour epithelium of OC MDTs treated with Ran inhibitors to that of controls. Preliminary results from patient samples demonstrate a concentration-dependent decrease in the area of KI67+ cells after 24 hrs of incubation, followed by an increase in the area of CC3+ cells after 72 hrs of incubation.

Conclusions: OC MDTs provide a rich model to test new small molecules that inhibit Ran. While a larger patient sample cohort needs to be further studied, our data suggest the potential therapeutic efficiency of these inhibitors for tumors displaying high aneuploidy.