YTHDF1-mediated RNA m1A methylation promotes malignant progression of hepatocellular carcinoma via regulating LRP5/Wnt-β-catenin axis.

The YTH domain family protein 1 (YTHDF1), a key N1-methyladenosine (mA) modification reader protein, has been significantly associated with the proliferation and invasion of various malignant cells. However, knowledge of the precise role of YTHDF1 in hepatocellular carcinoma (HCC) and the molecular mechanisms involving RNA mA modification remains incomplete. This study integrated HCC data from The Cancer Genome Atlas (TCGA), tissue microarray (TMA), in vitro functional experiments, and in vivo xenograft models to explore the regulatory role of YTHDF1-mediated RNA mA modification in HCC. Bioinformation analysis and TMA revealed that YTHDF1 expression is significantly upregulated in HCC tissues and correlated with poor prognosis of HCC patients. Functional experiments demonstrated that YTHDF1 knockdown markedly suppresses the proliferation and invasion of HCC cells, which was further confirmed by in vivo xenograft models. Integrated mA methylated RNA immunoprecipitation sequencing (MeRIP-seq), MeRIP-qPCR, transcriptome-sequencing (RNA-seq) and RNA immunoprecipitation-qPCR (RIP-qPCR) showed the distribution change of mA modifications after YTHDF1 knockdown, identified LRP5 as the downstream target of YTHDF1, and confirmed the direct binding of YTHDF1 to LRP5 mRNA. The Actinomycin D and dual-luciferase reporter assays confirmed that YTHDF1 can affect the stability of LRP5 mRNA. Further in vitro experiments indicated that YTHDF1 knockdown reduces the protein levels of key Wnt pathway components and inhibits the cell malignant phenotype, while LRP5 overexpression reverses the effects induced by YTHDF1 knockdown. In conclusion, YTHDF1-mediated RNA mA modifications facilitate the malignant progression of HCC by modulating the LRP5/Wnt/β-catenin signaling pathway.