Harnessing m(6)A-regulated cholesterol biosynthesis helps impede tumor burden and stemness in high-garde serous ovarian carcinoma mesenchymal phenotype.

Post-transcriptional RNA modifications have emerged as critical regulators of stemness, cellular plasticity, adaptation to stress and transformation. Amongst these the N6-methyladenosine (m(6)A) modification orchestrates a wide range of physiological processes; yet its contribution to metabolic regulation remains poorly addressed. In the present study, differential proteomics revealed enrichment of core components of the m(6)A machinery, viz. WTAP (writer) and IGF2BP3 (reader) in stem-like cells of the mesenchymal subtype of High-Grade Serous Ovarian Carcinoma (HGSC). Intriguingly, components of de novo cholesterol biosynthesis were also enriched. In investigating the suggested link between m(6)A regulation and sterol metabolism, we established a m(6)A-dependent stabilization of transcripts encoding rate-limiting de novo cholesterol biosynthetic enzymes by IGF2BP3 towards sustaining cholesterol production. Disruption of this cross-regulation by pharmacological inhibition impaired cell survival, self-renewal, and migration. Analyses of datasets from The Cancer Genome Atlas (TCGA) assigned a clinical significance to this regulatory axis through correlation of elevated expression of de novo cholesterol biosynthetic genes with poor progression-free survival of serous ovarian carcinoma patients. IGF2BP3 knock down, and chemical blockade of de novo cholesterol biosynthesis, both alone or in combination, achieved attenuated disease progression, in vivo. Effectively, our study links RNA modifications with metabolic reprogramming in the HGSC mesenchymal subtype through delineation of a m(6)A-IGF2BP3-cholesterol biosynthesis axis-mediated regulation of tumor cell stemness and aggression.