OTX1 silencing suppresses ovarian cancer progression through inhibiting the JAK/STAT signaling

The aim of our study was to investigate the roles and the underlying mechanisms of orthodenticle homolog 1 (OTX1) in ovarian cancer. OTX1 expression was obtained from TCGA database. OTX1 expression in ovarian cancer cells was detected using qRT-PCR and western blot assay. The cell viability and proliferation was detected by CCK-8 and EdU assays. Cell invasion and migration were detected by transwell assay. Flow cytometry was utilized to determine cell apoptosis and cycle. In addition, western blot assay was used to detect the expression of cell cycle related protein (Cyclin D1 and p21), epithelial-mesenchymal transition (EMT) related protein (E-cadherin, N-cadherin, Vimentin, and Snail), apoptosis related protein (Bcl-2, Bax, and cleaved caspase-3), and JAK/STAT pathway related protein (p-JAK2, JAK2, STAT3, and p-STAT3). OTX1 was highly expressed in ovarian cancer tissues and cells. OTX1 silencing blocked the cell cycle and repressed cell viability, proliferation, invasion, and migration, while OTX1 silencing facilitated the apoptosis of OVCAR3 and Caov3 cells. OTX1 silencing increased the protein levels of p21, E-cadherin, Bax, and cleaved caspase-3, while the protein levels of Cyclin D1, Bcl-2, N-cadherin, Vimentin, and Snail were decreased by OTX1 silencing. Furthermore, OTX1 silencing suppressed the protein levels of p-JAK2/JAK2 and p-STAT3/STAT3 in OVCAR3 and Caov3 cells. Moreover, overexpression of OTX1 promoted cell proliferation and invasion and inhibited apoptosis in Caov3 cells, but AG490 (an inhibitor of JAK/STAT pathway) reversed the influences on cell biological behavior induced by overexpression of OTX1. OTX1 silencing repressed ovarian cancer cell proliferation, invasion, and migration and induced cell apoptosis, which might be involved in JAK/STAT signaling pathway. OTX1 may be considered as a novel therapeutic target for ovarian cancer.