RNA demethylase ALKBH5 regulates hypopharyngeal squamous cell carcinoma ferroptosis by posttranscriptionally activating NFE2L2/NRF2 in an m6A-IGF2BP2-dependent manner

Abstract

Background: Having emerged as the most abundant posttranscriptional internal mRNA modification in eukaryotes, N6-methyladenosine (m6A) has attracted tremendous scientific interest in recent years. However, the functional importance of the m6A methylation machinery in ferroptosis regulation in hypopharyngeal squamous cell carcinoma (HPSCC) remains unclear. Methods: We herein performed bioinformatic analysis, cell biological analyses, transcriptome-wide m6A sequencing (m6A-seq, MeRIP-seq), RNA sequencing (RNA-seq), and RNA immunoprecipitation sequencing (RIP-seq), followed by m6A dot blot, MeRIP-qPCR, RIP-qPCR, and dual-luciferase reporter assays. Results: The results revealed that ALKBH5-mediated m6A demethylation led to the posttranscriptional inhibition of NFE2L2/NRF2, which is crucial for the regulation of antioxidant molecules in cells, at two m6A residues in the 3′-UTR. Knocking down ALKBH5 subsequently increased the expression of NFE2L2/NRF2 and increased the resistance of HPSCC cells to ferroptosis. In addition, m6A-mediated NFE2L2/NRF2 stabilization was dependent on the m6A reader IGF2BP2. We suggest that ALKBH5 dysregulates NFE2L2/NRF2 expression in HPSCC through an m6A-IGF2BP2-dependent mechanism. Conclusion: Together, these results have revealed an association between the ALKBH5-NFE2L2/NRF2 axis and ferroptosis, providing insight into the functional importance of reversible mRNA m6A methylation and its modulators in HPSCC.