Silencing of the STAT3 signaling pathway reverses the inherent and induced chemoresistance of human ovarian cancer cells.

•High levels of p-STAT3 are associated with chemoresistance in ovarian cancer cells.•Knockdown of STAT3 expression enhanced cisplatin-induced apoptosis.•IL-6 induced STAT3 phosphorylation and rescued ovarian cancer cells from apoptosis.•Blockade of STAT3 signaling reduced IL-6-induced anti-apoptosis.•Targeting STAT3 signaling could activate the apoptosis pathway of mitochondria.