mA demethylase FTO stabilizes LINK-A to exert oncogenic roles via MCM3-mediated cell-cycle progression and HIF-1α activation.

RNA N-methyladenosine (mA) modification is implicated in cancer progression, yet its role in regulating long noncoding RNAs during cancer progression remains unclear. Here, we report that the mA demethylase fat mass and obesity-associated protein (FTO) stabilizes long intergenic noncoding RNA for kinase activation (LINK-A) to promote cell proliferation and chemoresistance in esophageal squamous cell carcinoma (ESCC). Mechanistically, LINK-A promotes the interaction between minichromosome maintenance complex component 3 (MCM3) and cyclin-dependent kinase 1 (CDK1), increasing MCM3 phosphorylation. This phosphorylation facilitates the loading of the MCM complex onto chromatin, which promotes cell-cycle progression and subsequent cell proliferation. Moreover, LINK-A disrupts the interaction between MCM3 and hypoxia-inducible factor 1α (HIF-1α), abrogating MCM3-mediated HIF-1α transcriptional repression and promoting glycolysis and chemoresistance. These results elucidate the mechanism by which FTO-stabilized LINK-A plays oncogenic roles and identify the FTO/LINK-A/MCM3/HIF-1α axis as a promising therapeutic target for ESCC.