PO-026 Metformin inhibits the NGF-induced increase c-MYC and VEGF levels in ovarian cancer cells

Abstract

IntroductionEpithelial ovarian cancer (EOC) is a lethal malignance characterised by high levels of angiogenic and growth factors. Nerve Growth Factor (NGF) is overexpressed in EOC and promotes proliferation, survival and angiogenesis in EOC models. NGF stimulation of EOC explants increases proteins levels of c-MYC transcription factor and vascular endothelial growth factor (VEGF), both oncogenic proteins. Besides, the anti-diabetic drug metformin can regulates signalling pathways that can be activated by NGF: previous results have shown that metformin can prevent proliferative and pro-angiogenic effects of NGF in the EOC and endothelial cells, so that we wanted to deepen in the mechanism of metformin action. The aim of this study was to evaluate c-MYC and VEGF levels in A2780 cells stimulated with NGF and metformin.Material and methodsA2780 cells were stimulated with NGF (100 ng/mL; 2 or 24 hours) and/or metformin (10 mM; 48 hours). Then, supernatant were collected to measure VEGF through ELISA and cells were used to detect c-MYC protein levels by western blotting and immunocytochemistry.Results and discussionsNGF stimulation increased c-MYC protein levels in A2780 cells at 2 and 24 hours of (p<0.05) and also NGF increased levels of VEGF in culture medium from A2780 cells (p<0.05). Furthermore, pharmacologic inhibition of TRKA receptor with GW441756 or the use of a neutralising antibody anti-NGF, blocked the increase of c-MYC and VEGF by NGF (p<0.05). On the other hand, metformin produced a strong decrease of VEGF and c-MYC protein levels compared with the baseline condition (p<0.05). Significantly, the co-treatment of metformin and NGF prevented the increase of c-MYC and VEGF by NGF stimulation (p<0.05). These results confirm the pro-tumoral role of NGF, and support previous findings that show that NGF increases proliferation and angiogenesis in EOC, where c-MYC and VEGF could be implicated in these processes. Moreover, our results reinforce that metformin have anti-tumoral effects, and part of its mechanism could involve blocking the effects of growth factors, such as NGF.ConclusionGiven that current therapies yield modest results in EOC patients and NGF plays a significant role in EOC progression, our current findings suggest that metformin holds considerable promise as an adjuvant treatment in ovarian cancer.GrantsFONDECYT #1160139 and CONICYT scholarship # 21150360