No abstract

We assessed the anti-proliferative activity of itraconazole using an EOC cell line (SKOV3ip1) and endothelial cell lines (HUVEC & SVEC4-10). We also examined angiogenesis (VEGFR2, p-ERK, p-PLCr1/2), hedgehog (Gli1, Ptch1, SMO), and mTOR (pS6K1) signaling pathways to determine the mechanism of action of itraconazole. Furthermore, we evaluated the synergistic effects of itraconazole and paclitaxel using orthotopic mouse models with established EOC cells (SKOV3ip1 or HeyA8) as well as patient-derived xenografts (PDXs). Itraconazole treatment inhibited proliferation of endothelial cells in a dose-dependent manner, but had no effect on EOC cells. The endothelial cell antiproliferative effect was associated with inhibition of hedgehog, and mTOR pathways and angiogenesis. In xenograft models of EOC using SKOV3ip1 or HeyA8, mice treated with the combination of itraconazole and paclitaxel had significantly decreased tumor weight than the control, paclitaxel-alone, or itraconazole-alone groups. Tissue derived from these tumors had significantly lower microvessel density than tissue from the other groups as well as hedgehog and mTOR pathway inhibition. We confirmed those effects in two EOC PDX models. These results suggest that itraconazole selectively inhibits endothelial cells rather than cancer cells by targeting multiple pathways including hedgehog, and mTOR pathways and angiogenesis.

Ovarian clear cell carcinoma (OCCC) displays a higher resistance to first line chemotherapy, requiring the development of new therapeutics. We previously identified a frequent chromosomal gain at 8q24 that harbors the focal-adhesion kinase (FAK) gene; the potential of this gene as a therapeutic target remains to be evaluated in OCCCs. We first examined the dependence of OCCCs on FAK and the PI3K/AKT signaling pathway. FAK was overexpressed in 20% of 67 OCCC samples, and this overexpression was correlated with its copy number gain. FAK copy number gains and mutations in PIK3CA accounted for about 40% of OCCC samples, suggesting that the FAK/PI3K/AKT axis is an attractive candidate for targeted therapeutics. We, therefore, treated ovarian cancer cell lines, including OCCC subtypes, with the FAK inhibitors PF-562,271 (PF271), and PF-573,228 (PF228). Ovarian cancer cells were more sensitive to PF271 than PF228. We then searched for single agents that exhibited a synergistic effect on cell death in combination with PF271. We found that co-treatment of PF271 with ABT-737, a BCL-2/BCL-XL antagonist, was profoundly effective at inducing apoptosis. RMGI and OVISE cells were more sensitive to ABT-737 than OVMANA and SKOV3 cells, which have PIK3CA mutations. Mechanistically, PF271 treatment resulted in the transient down-regulation of the anti-apoptotic protein MCL1 via the PI3K/AKT pathway. Therefore, PF271/ABT-737 treatment led to the inhibition of the anti-apoptotic proteins MCL1 and BCL-XL/BCL-2. We suggest that pharmacological inhibition of BCL-XL and FAK/PYK2 can be a potential therapeutic strategy for the treatment of OCCC.