m6A-modified RIPK4 facilitates proliferation and cisplatin resistance in epithelial ovarian cancer

Background. Cisplatin (DDP)-based chemotherapy is a common chemotherapeutic regimen for the treatment of advanced epithelial ovarian cancer (EOC). However, most patients rapidly develop chemoresistance. N6-methyladenosine (m6A) is a pervasive RNA modification, and its specific role and potential mechanism in the regulation of chemosensitivity in EOC remain unclear.Methods. The expression of RIPK4 and its clinicopathological impact were evaluated in EOC cohorts. The biological effects of RIPK4 were investigated using in vitro and in vivo models. RNA m6A quantification was used to measure total m6A levels in epithelial ovarian cancer cells. Luciferase reporter, MeRIP-qPCR, RIP-qPCR and actinomycin-D assays were used to investigate RNA/RNA interactions and m6A modification of RIPK4 mRNA.Results. We demonstrated that RIPK4, an upregulated mRNA in EOC, acts as an oncogene in EOC cells by pro-moting tumor cell proliferation and DDP resistance at the clinical, database, cellular, and animal model levels. Mechanistically, METTL3 facilitates m6A modification, and YTHDF1 recognizes the specific m6A-modified site to prevent RIPK4 RNA degradation and upregulate RIPK4 expression. This induces NF-KB activation, resulting in tumor growth and DDP resistance in vitro and in vivo.Conclusions. Collectively, the present findings reveal a novel mechanism underlying the induction of DDP re-sistance by m6A-modified RIPK4, that may contribute to overcoming chemoresistance in EOC.(c) 2023 The Authors. Published by Elsevier Inc.This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).