Phosphorylation of Cofilin-1 Enhances Paclitaxel Resistance of Epithelial Ovarian Cancer Cells by Inhibiting Apoptosis

Objective To investigate the molecular mechanism of high phosphorylation levels of cofilin-1(p-CFL-1)associated with paclitaxel resistance in epithelial ovarian cancer(EOC)cells.Methods Cells displaying varying levels of p-CFL-1 and CFL-1 were created by plasmid transfection and shRNA interference.Cell inhibition rate indicating paclitaxel efficacy was assessed by Cell Counting Kit-8(CCK-8)assay.Apoptosis was assessed by flow cytometry and protein levels were detected by western blotting.Quantitative real-time polymerase chain reaction(qRT-PCR)was used to measure the expression levels of phosphokinases and phosphatases of CFL-1.Survival analysis evaluated the correlation between the prognosis of EOC patients and the levels of p-CFL-1 and slingshot-1(SSH-1).Results High levels of p-CFL-1 were observed in EOC cells that survived treatment with high doses of paclitaxel.SKOV3 cell mutants with upregulated p-CFL-1 showed impaired paclitaxel efficacy,as well as decreased apoptosis rates and pro-survival patterns of apoptosis-specific protein expression.Cytoplasmic accumulation of p-CFL-1 inhibited paclitaxel-induced mitochondrial apoptosis.SSH-1 silencing mediated CFL-1 phosphorylation in paclitaxel-resistant SKOV3 cells.Clinically,the high level of p-CFL-1 and the low level of SSH-1 in EOC tissues were closely related to chemotherapy resistance and poor prognosis in EOC patients.Conclusion The SSH-1/p-CFL-1 signaling pathway mediates paclitaxel resistance by apoptosis inhibition in EOC and is expected to be a potential prognostic predictor.