METTL1 promotes Neuroblastoma development through m 7 G tRNA modification and selective oncogenic gene translation

Background: Neuroblastoma (NBL) is a common but aggressive malignancy with a poor prognosis in childhood. Despite existing therapy approaches, the 5-year survival rate for patients with advanced NBL remains below 30%, emphasizing urgent necessary for novel therapeutic strategies. Studies have shown that epigenetic disorders play an essential role in the pathogenesis of NBL. However, the function and mechanism of N7-methylguanosine (m 7 G) methyltransferase in NBL remains unknown. Methods: The expression levels of m 7 G tRNA methyltransferase METTL1 (Methyltransferase-like 1) were analyzed by querying the GEO database and further confirmed by immunohistochemistry (IHC) assay. The prognostic role of METTL1 were analyzed by the R2 genomics analysis and visualization platform. Function studies were performed to evaluate how METTL1 works in proliferation, apoptosis and migration in cell lines and xenograft mouse models. The role of METTL1 on NBL cells mRNA translation activity was measured using puromycin intake assay and polysome profiling assay. The m 7 G modified tRNAs were identified by tRNA reduction and cleavage sequencing (TRAC-seq). Ribosome nascent-chain complex-bound mRNA sequencing (RNC-seq) was utilized to analyzed genes with alterative translation efficiency. Analyzed the codon frequency decoded by m 7 G tRNA in genes to clarify the mechanism of m 7 G modification in translation regulation. Results: This study found METTL1 was significantly upregulated in advanced NBL and was associated with a poor prognosis. Further in vitro and in vivo assays showed METTL1 played a crucial role in promoting NBL progression. Furthermore, m 7 G profiling and translation analysis revealed downregulation of METTL1 inhibited puromycin intake efficiency of NBL cells, indicating the crucial METTL1 did count in regulation of NBL cell translation. With all tRNAs with m 7 G modification identified in NBL cells, METTL1 knockdown significantly lowered both m 7 G modification level and m 7 G tRNAs expressions. RNC-seq revealed 339 overlapped genes with impaired translation in NBL cells upon METTL1 knockdown. Further analysis revealed these genes contained higher frequency of codons decoded by m 7 G-modified tRNAs and were enriched in oncogenic pathways. Conclusion: This study revealed the critical role and mechanism of METTL1-mediated tRNA m 7 G modification in regulating NBL progression, providing new insights for developing therapeutic approaches for NBL patients.