NKX2-8 deletion-induced reprogramming of fatty acid metabolism confers chemoresistance in epithelial ovarian cancer

Background: Aberrant fatty acid (FA) metabolism is a unique vulnerability of cancer cells and may present a promising target for cancer therapy. Our study aims to elucidate the molecular mechanisms by which NKX2-8 deletion reprogrammed FA metabolism-induced chemoresistance in epithelial ovarian cancer (EOC). Methods: The deletion frequency and expression of NKX2-8 in 144 EOC specimens were assayed using fluorescence in situ hybridization and immunochemical assays. The effects of NKX2-8 deletion and the fatty acid oxidation (FAO) antagonist Perhexiline on chemoresistance were examined by Annexin V and colony formation in vitro, and via an intraperitoneal tumor model in vivo. The mechanisms of NKX2-8 deletion in reprogrammed FA metabolism was determined using Chip-seq, metabolomic analysis, FAO assays and immunoprecipitation assays. Findings: NKX2-8 deletion was correlated with the overall and relapse-free survival of EOC patients. NKX2-8 inhibited the FAO pathway by epigenetically suppressing multiple key components of the FAO cascade, including CPTIA and CPT2. Loss of NKX2-8 resulted in reprogramming of FA metabolism of EOC cells in an adipose microenvironment and leading to platinum resistance. Importantly, pharmacological inhibition of FAO pathway using Perhexiline significantly counteracted NKX2-8 deletion-induced chemoresistance and enhanced platinum's therapeutic efficacy in EOC. Interpretation: Our results demonstrate that NKX2-8 deletion-reprogrammed FA metabolism contributes to chemoresistance and Perhexiline might serve as a potential tailored treatment for patients with NKX2-8-deleted EOC. (C) 2019 The Authors. Published by Elsevier B.V.