N6-methyladenosine facilitates mitochondrial fusion of colorectal cancer cells via induction of GSH synthesis and stabilization of OPA1 mRNA

Abstract

Mitochondria undergo fission and fusion that are critical for cell survival and cancer development, while the regulatory factors for mitochondrial dynamics remain elusive. Herein we found that RNA m⁶A accelerated mitochondria fusion of colorectal cancer (CRC) cells. Metabolomics analysis and function studies indicated that m⁶A triggered the generation of glutathione (GSH) via the upregulation of RRM2B-a p53-inducible ribonucleotide reductase subunit with anti-reactive oxygen species potential. This in turn resulted in the mitochondria fusion of CRC cells. Mechanistically, m⁶A methylation of A1240 at 3'UTR of RRM2B increased its mRNA stability via binding with IGF2BP2. Similarly, m⁶A methylation of A2212 at the coding sequence (CDS) of OPA1-an essential GTPase protein for mitochondrial inner membrane fusion-also increased mRNA stability and triggered mitochondria fusion. Targeting m⁶A through the methyltransferase inhibitor STM2457 or the dm⁶ACRISPR system significantly suppressed mitochondria fusion. In vivo and clinical data confirmed the positive roles of the m⁶A/mitochondrial dynamics in tumor growth and CRC progression. Collectively, m⁶A promoted mitochondria fusion via induction of GSH synthesis and OPA1 expression, which facilitated cancer cell growth and CRC development.

Keywords: OPA1; colorectal cancer; glutathione; m6A; mitochondrial fusion.