Hypoxia-induced m⁶A demethylation promotes hepatocellular carcinoma progression by preventing the degradation of Gal-1 mRNA

Increasing evidence indicates that the galectin family played a significant role in tumor progression and is closely related to the hypoxic microenvironment within tumor tissues. However, the regulatory mechanisms behind this process are unexplored. In this study, we found that Gal-1 expression was significantly up-regulated in hepatocellular carcinoma (HCC) tissues and was closely associated with poor prognosis of patients. Intervention of Gal-1 at the cellular level significantly inhibited the malignant phenotype of hepatoma cells. For the first time, we discovered that Gal-1 was regulated by m⁶A modification, ALKBH5 mediated the demethylation of Gal-1 mRNA, and YTHDF2 recognized Gal-1 mRNA and altered its stability. This regulatory process was altered under hypoxic conditions, and hypoxia-inducible factors (HIFs) mediated the regulation of m⁶A modification in hepatoma cells by hypoxia. HIF-1α bound to the promoter region of ALKBH5 and up-regulated ALKBH5 expression, while HIF-2α bound to the promoter region of YTHDF2 and generated negative regulation. In vivo, after intervention of Gal-1, reduction of proliferative markers and inhibition of epithelial–mesenchymal transition occurred in the subcutaneous tumor. The use of LNP-siGal-1 also inhibited epithelial–mesenchymal transition.