m6A mRNA Methylation Regulates LKB1 to Promote Autophagy of Hepatoblastoma Cells through Upregulated Phosphorylation of AMPK.

The N6-methyladenosine (m6A) RNA modification can regulate autophagy to modulate the growth and development of tumors, but the mechanism of m6A modification for the regulation of autophagy in hepatocellular carcinoma cells (HCC) remains unclear. In the study, the knockdown of the Wilms' tumor 1-associating protein (WTAP) was made in HCC to study the correlation between m6A modification and autophagy. A fluorescent confocal microscopy analysis showed that the knockdown of WTAP could facilitate the autophagy of HCC. A Western blot analysis showed that the level of p-AMPK was decreased in WTAP-knockdown HCC cells. Additionally, LKB1, the upstream kinase of AMPK, was regulated by WTAP and it could mediate the phosphorylation of AMPK in an m6A-dependent manner. Further studies revealed that the knockdown of WTAP could reduce the level of LKB1 mRNA with m6A. This could result in the increased stability of LKB1 mRNA to promote its expression. The knockdown of WTAP could upregulate the level of autophagy and inhibit HCC proliferation. However, the overexpression of WTAP could resist autophagic cell death.