Pan-Cancer Analysis Identifies tRNA Modification Enzyme CTU2 as a Novel Tumor Biomarker and Its Role in Immune Microenvironment

Jiaojiao WangChang GaoJunyi ZhangHuahong LuoSiqi Dai^*Jianwei Wang^*

• Zhejiang University, Hangzhou, China

Recent studies have highlighted dysregulated tRNA modifications in tumor translation reprogramming. Cytosolic thiouridylase subunit 2 (CTU2) is an essential and conserved enzyme that modifies tRNA at the wobble position. However, the relationship between CTU2 expression and various cancer types remains insufficiently explored. In this study, we utilized pan-cancer data from multiple databases to investigate the expression patterns and prognostic value of CTU2. Single-cell and spatial transcriptomic analyses were performed to identify cell-type labels and examine the spatial distribution of CTU2. The TCGA microRNA database was used to explore the expression patterns of CTU2-modified tRNA molecules and their prognostic significance. We also investigated the relationship between CTU2 expression in tumor tissues and immune infiltration patterns, immune evasion, and immunotherapy response.Additionally, GSEA analysis was conducted to identify signaling pathways associated with CTU2. The oncogenic roles of CTU2 in various cancers were further validated through in vitro and in vivo experiments. A drug sensitivity analysis related to CTU2 was performed. Finally, genomic alterations, publicly ChIP-seq datasets, dual luciferase reporter assay, and EMSA were integrated to investigate the upstream regulatory mechanisms controlling CTU2 expression. In summary, our study integrates multiomics data to elucidate the role of CTU2 and its modified tRNA in diverse cancers, providing new insights into tumor treatment strategies and immune evasion from the perspective of tRNA modifications.