Ythdf2 Accelerates Lymphangiogenesis In Oscc Through Rnf43/Wnt5b Pathway

The aim of this study is to investigate the role of N6-methyladenosine (m6A), the most abundant intrinsic mRNA modification in eukaryotes, in lymphangiogenesis and lymphatic metastasis in oral squamous cell carcinoma (OSCC). The levels of m6A modifications and YTH domain-containing family protein 2 (YTHDF2) in samples are detected by dot blot, qRT-PCR, western blot and immunohistochemistry. Tube formation and migration assays are conducted to examine the effect of YTHDF2 expression in the biological function of Human Lymphatic Endothelial Cells (HLECs). The lymphatic vessel density is evaluated through immunohistochemistry and immunofluorescence. The downstream target genes of YTHDF2 are identified through RNA sequencing (RNA-seq) and methylated RNA immunoprecipitation sequencing (MeRIP-seq), followed by validation of transcript functions using actinomycin D and RNA immunoprecipitation PCR. The mechanism in vivo was verified by in nude mice orthotopic xenograft model. In vitro experiments showed that YTHDF2 can enhance the migration and invasion abilities of OSCC cells, and YTHDF2 can also accelerate the tube formation and migration abilities of HLECs. In vivo experiments demonstrated that silencing YTHDF2 expression decreased the lymphatic vessel density in orthotopic tumors and inhibited the ability of OSCC to metastasize to the neck lymph nodes. Mechanically, RNA-seq and MeRIP-seq demonstrated that YTHDF2-regulated differentially expressed genes were enriched in the WNT pathway, and YTHDF2 recognized m6A sties and accelerated RNF43 mRNA degradation leading to upregulate WNT5B expression. YTHDF2 drives lymphangiogenesis and lymphatic metastasis in OSCC by increasing WNT5B through m6A-dependent degradation of RNF43 mRNA.