MIR937 amplification potentiates ovarian cancer progression by attenuating FBXO16 inhibition on ULK1-mediated autophagy

Abstract

Abstract High-grade serous ovarian carcinoma (HGSOC) is one of the most lethal gynecological cancer. Genetic studies have revealed gene copy number alterations (CNAs) frequently occurred in HGSOC pathogenesis, however the function and mechanism of CNAs for microRNAs are still not fully understood. Here, we show the dependence on gene copy number amplification of MIR937 that enhances cell autophagy and dictates HGSOC proliferative activity. Data mining of TCGA database revealed MIR937 amplification is correlated with increased MIR937 expression and cell proliferation of HGSOC. Deletion of MIR937 in HGSOC cells led to impaired autophagy and retarded cell proliferation, and the extent for its inhibitory effects scaled with the degree of MIR937 copy loss. Rescue assay confirmed miR-937-5p, a mature product of MIR937, was sufficient to restore its oncogenic function. Mechanistically, MIR937 amplification raised the expression of miR-937-5p, enhanced its binding to 3′ UTR of FBXO16 transcript, and thereby restricting FBXO16 degradative effects on ULK1. Our results demonstrate that MIR937 amplification augments cell autophagy and proliferation, and suggest an alternative strategy of MIR937/FBXO16/ULK1 targeting for HGSOC treatment.