Everolimus Exhibits Antitumor Activity In Obesity-induced Ovarian Cancer

Background Mammalian target of rapamycin(m TOR) is a central regulator that integrates various pathways involved in cell proliferation, metabolism, angiogenesis and cell survival.Everolimus(RAD001) inhibits m TOR kinase activity and its downstream targets by acting on m TORC1 and has anti-tumorigenic activity in many types of cancers, including ovarian cancer. Clinical and epidemiologic data find that obesity is associated with worse outcomes in ovarian cancer. In addition, obesity leads to hyperactivation of the m TOR pathway in epithelial tissues, suggesting that m TOR inhibitors may be a logical choice for treatment in obesity-driven cancers. However, it remains unclear if obesity impacts the effect of everolimus on tumor growth in ovarian cancer. Thus,our study will investigate the impact of everolimus on the vitro and vivo proliferative and metabolic effects with different glucose concentration, and evaluate the effect on obese mouse with ovarian cancer.Methods The effect of everolimus on growth inhibitory was examined in ovarian cancer cell lines by MTT assay, colony formation, Annexin V-FITC and Flow cytometry. We investigated the effect of everolimus on production of cellular reactive oxygen by DCFH assay. Cell adhension and invasion were performed using 96-well HTS transwells. Glucose uptake was detected by 2-NBDG. ATP level was assessed by Luminometric ATP Assay Kit.Lactate production was measured by L-Lactate Assay Kit. VEGF production in the medium and serum were detected by using the VEGF Aasay Kit. P-AKT, P-S6, CDK6, cyclin D1?Mcl-1?Bcl-2?P21?MMP-9 protein expression were detected by Western immunoblotting. The expression of Ki-67, P-S6, P-AKT and cleaved caspase-3 in tumor tissues was evaluated by IHC. Metabolomic profiling was used to analyze tumors' metabolomic production after treatment of everolimus.Results Everolimus significantly inhibited cellular proliferation, induced cell cycle G1 arrest and apoptosis, reduced invasion and caused cellular stress via inhibition of m TOR pathways in ovarian cancer cell lines. Hypoglycemic conditions enhanced the sensitivity of cells to everolimus through the disruption of glycolysis. Moreover, everolimus was found to reduce ovarian tumor weight and volume in both obese and lean mice. This reduction coincided with a decrease in expression of Ki-67 and phosphorylated-S6, as well as an increase in cleaved caspase 3 and phosphorylated-AKT. Metabolite profiling revealed that everolimus was able to alter tumor metabolism through affecting different metabolic pathways in the obese and lean mouse models.Conclusion Our findings support that everolimus may be a promising therapeutic agent for obesity-driven ovarian cancers.