Apatinib inhibits glycolysis by suppressing the VEGFR2/AKT1/SOX5/GLUT4 signaling pathway in ovarian cancer cells

Abstract

Background: Apatinib is a tyrosine kinase inhibitor that targets vascular endothelial growth factor receptor-2 (VEGFR2), and has shown encouraging therapeutic effects in various malignant tumors. As yet, however, the role of apatinib in ovarian cancer has remained unknown. Here, we sought to elucidate the role of apatinib in the in vitro and in vivo viability and proliferation of ovarian cancer cells, as well as in glucose metabolism in these cells. Methods: The effects of apatinib on ovarian cancer cell viability and proliferation were assessed using Cell Counting Kit-8 (CCK-8) and colony formation assays, respectively. The expression of VEGFR2/AKT1/SOX5/GLUT4 pathway proteins was assessed using Western blotting, and glucose uptake and lactate production assays were used to detect glycolysis in ovarian cancer cells. SOX5 was exogenously over-expressed and silenced in ovarian cancer cells using expression vector and shRNA-based methods, respectively. RNA expression analyses were performed using RNA-seq and gene-chip-based methods. GLUT4 promoter activity was assessed using a dual-luciferase reporter assay. The expression of p-VEGFR2 (Tyr1175), p-AKT1 (Ser473), p-GSK3β (Ser9), SOX5 and GLUT4 in xenograft tissues was assessed using immunohistochemistry (IHC). Results: We found that apatinib inhibited the in vitro and in vivo viability and proliferation in Hey and OVCA433 ovarian cancer cells in a dose-dependent and time-dependent manner. We also found that apatinib effectively suppressed glucose uptake and lactate production by blocking the expression of GLUT4 in these cells. In addition, we found that SOX5 predominantly rescued the inhibitory effect of apatinib on GLUT4 expression by activating its promoter. Finally, we found that apatinib regulated the expression of SOX5 by suppressing the VEGFR2/AKT1/GSK3β signaling pathway. Conclusions: From our results, we conclude that apatinib suppresses the in vitro and in vivo viability and proliferation of ovarian cancer cells, as well as glycolysis by inhibiting the VEGFR2/AKT1/GSK3β/SOX5/GLUT4 signaling pathway. Apatinib may serve as a promising drug for the treatment of ovarian cancer.