Exosome-derived circTRPS1 promotes malignant phenotype and CD8+T cell exhaustion in bladder cancer microenvironments

Circular RNAs (circRNAs) play critical roles in different dis-eases. Exosomes are important intermediates of intercellular communication. While both have been widely reported in can-cers, exosome-derived circRNAs are rarely studied. In this work, we identified the differently expressed circRNAs in bladder cancer (BCa) tissue and exosomes through high-throughput sequencing. RNA pull-down, RNA immunoprecip-itation, and luciferase reporter assays were used to investigate the interactions between specific circRNAs, microRNAs (miR-NAs), and mRNAs. Wound-healing, Transwell, Cell Counting Kit-8 (CCK8), and colony-formation assays were used to study the biological roles in vitro. Metabolomics were used to explore the mechanism of how specific circRNAs influenced BCa cell behavior. Flow cytometry was used to study how specific circR-NAs affected the function of CD8+ T cells in tumor microenvi-ronments. We identified that exosome-derived hsa_-circ_0085361 (circTRPS1) was correlated with aggressive phenotypes of BCa cells via sponging miR-141-3p. Metabolo-mics and RNA sequencing (RNA-seq) identified GLS1-medi-ated glutamine metabolism was involved in circTRPS1-medi-ated alterations. Exosomes derived from circTRPS1 knocked down BCa cells, prevented CD8+ T cells from exhaustion, and repressed the malignant phenotype of BCa cells. In conclu-sion, exosome-derived circTRPS1 from BCa cells can modulate the intracellular reactive oxygen species (ROS) balance and CD8+ T cell exhaustion via the circTRPS1/miR141-3p/GLS1 axis. Our work may provide a potential biomarker and thera-peutic target for BCa.

Automated summary

This study identified differentially expressed circRNAs in bladder cancer tissue and exosomes, and investigated their roles in cancer cell behavior and immune function. The findings revealed the regulatory function of exosome-derived circTRPS1 in BCa cells and provided potential therapeutic targets for BCa.