show Abstracthide AbstractThe cancer cells selectively promote the translation of specific oncogenic transcripts to stimulate cancer progression. Although growing evidence has revealed that tRNA modifications and related genes participate in this process, their roles in head and neck squamous cell carcinoma (HNSCC) remain largely uncharacterized. Here we found that tRNA m7G methyltransferase complex components METTL1/WDR4 were both upregulated in HNSCC and associated with poor prognosis. Functionally, METTL1/WDR4 promoted HNSCC progression and metastasis in cell-based and transgenic mouse models. Mechanistically, ablation of METTL1 reduced m7G levels of 16 tRNAs, causing translational inhibition of a subset of oncogenic transcripts, including the genes related to PI3K/AKT/mTOR signaling pathway. In addition, chemical modulators of PI3K/AKT/mTOR signaling pathway can reverse the effects of Mettl1 in HNSCC. Furthermore, single-cell RNA sequencing results revealed that depletion of Mettl1 in tumor cells altered the immune landscape and cell-cell interaction between tumor and stromal compartment. In summary, this study uncovered the physiological function and mechanism of mis-translation regulation mediated by tRNA m7G modification in HNSCC, and suggested that targeting METTL1 could be a promising treatment strategy for HNSCC patients. Overall design: TRAC-Seq were developed to identify the tRNA m7G methylome in HNSCC cell line. Polyribosome-bound-RNA-seq was used to study the differentially translated genes in the METTL1 knockout and control cells. Ribo-seq was performed to study the differentially translated genes and ribosome processivity in the METTL1 knockout and control cells. scRNA-seq of murine HNSCC from 4NQO-induced Mettl1cKO and wild type transgenic mice.