Chemokine CXCL-2 Regulates Resistance to Platinum in Epithelial Ovarian Cancer by Mediating ATR/CHK1 Signaling Pathway

Abstract Backgrounds：Platinum-resistance remains a challenge to recurrence and metastasis of epithelial ovarian cancer (EOC) and the mechanisms are unidentified. Tumor microenvironment (TME) and chemokine might play a key role in tumor chemoresistance. This study is designed to reveal the important role of CXCL-2 in causing EOC platinum-resistance. Materials and Methods: Differently expressed chemokines were selected based on the GSE114206 dataset of GEO database. Chemokines levels of platinum-sensitive and platinum-resistant EOC. Cell assays were performed and the cell stem characteristics were investigated for exploring the roles of CXCL-2 in EOC chemoresistance. We further explored the downstream signaling pathway regulated by CXCL-2 by detecting the expression of related molecules and rescue assay with the signaling inhibitor.Results: CXCL-2, CXCL-11 and CXCL-13 were found up-regulated in platinum-resistant EOC based on GSE114206 databases, and CXCL-2 was identified as key chemokine by validation. The cell assays showed overexpressing CXCL-2 and co-culturing with recombinant human CXCL-2 promoted cancer cell chemoresistance. Conversely, knocking down CXCL-2 and co-culturing with neutralizing antibody to CXCL-2 reduced cisplatin-resistance in cisplatin-resistant EOC cells. CXCL-2 levels regulated the stemness of cancer cells and activated ataxia telangiectasia and Rad3-related (ATR)/cell cycle checkpoint kinase1 (CHK1) signaling pathway. The cancer cell chemoresistance can be saved by CXCL-2 receptor inhibitor (SB225002) and CHK1 inhibitor (SAR-020106) in vitro. Conclusion: These results identified a CXCL-2 mediated platinum-resistance mechanism in EOC, and provided a novel target for chemoresistance prevention and treatment strategies.