WTAP participates in the DNA damage response via an m⁶A-FOXM1-dependent manner in hepatocellular carcinoma

N6-Methyladenosine (m⁶A) is one of the most abundant RNA modifications that occur in eukaryotes. The relationship between m⁶A methylation and DNA damage repair (DDR) is still unclear. As an important chaperone protein of m⁶A methyltransferase, the role of Wilm's tumor-associated protein (WTAP) in DDR has not been studied in detail. We identified that WTAP was markedly upregulated in HCC cells with DNA damage induction. Further investigations revealed that WTAP was engaged in DDR and WTAP knockdown resulted in a significant decrease of the stability of the DDR-related transcription factor Forkhead Box M1 (FOXM1) mRNA, eventually preventing DDR. WTAP deficiency inhibited cell growth both in vivo and in vitro. Moreover, WTAP silencing sensitized HCC cells to cisplatin, a well-known DNA damage agent. Altogether, our findings demonstrate that WTAP is the dominant m⁶A -related modulator upon DNA damage and functions by stabilizing FOXM1. In addition, WTAP deficiency saliently sensitized HCC cells to cisplatin both in vitro and in vivo.