N7-methylguanosine tRNA modification promotes tumorigenesis and chemoresistance through WNT/β-catenin pathway in nasopharyngeal carcinoma.

Treatment selections are very limited for patients with advanced nasopharyngeal carcinoma (NPC) experiencing disease progression. Uncovering mechanisms underlying NPC progression is crucial for the development of novel treatments. Here we show that N7-methylguanosine (m7G) tRNA modification enzyme METTL1 and its partner WDR4 are significantly elevated in NPC and are associated with poor prognosis. Loss-of-function and gain-of-function assays demonstrated that METTL1/WDR4 promotes NPC growth and metastasis in vitro and in vivo. Mechanistically, ARNT was identified as an upstream transcription factor regulating METTL1 expression in NPC. METTL1 depletion resulted in decreased m7G tRNA modification and expression, which led to impaired codon recognition during mRNA translation, therefore reducing the translation efficiencies of mRNAs with higher m7G codons. METTL1 upregulated the WNT/β-catenin signaling pathway and promoted NPC cell epithelial-mesenchymal transition (EMT) and chemoresistance to cisplatin and docetaxel in vitro and in vivo. Overexpression of WNT3A bypassed the requirement of METTL1 for EMT and chemoresistance. This work uncovers novel insights into tRNA modification-mediated mRNA translation regulation and highlights the critical function of tRNA modification in cancer progression.