Abstract 3941: A RHO GTPase pathway signature as a potential prognostic biomarker and therapeutic target in bladder cancer.

Abstract Background: The RHO GTPase cycle regulates essential cellular processes, including proliferation, differentiation, senescence, and programmed cell death. However, many predicted downstream effectors of this pathway remain poorly characterized, and their prognostic relevance in bladder cancer (BLCA) is not well understood. This study aimed to develop a prognostic model for BLCA based on RHO GTPase cycle effector gene expression and to identify key effectors functionally involved in BLCA progression. Methods: RNA-seq data and clinical information from The Cancer Genome Atlas (TCGA) and our James institutional cohort were analyzed. LASSO and Cox regression analyses were used to construct a prognostic gene signature associated with the RHO GTPase cycle. Patients were stratified into high- and low-risk groups based on this signature. Pathway enrichment analyses and therapy-response predictions were performed to compare biological features between risk groups. Candidate effector genes were functionally validated in BLCA cell lines using shRNA-mediated knockdown, followed by proliferation and colony-formation assays. Results: The resulting gene signature reliably stratified patients into high- and low-risk groups, with Kaplan-Meier curves showing significantly reduced survival in the high-risk group. These findings were validated in our independent dataset. Among the signature genes, UACA, CLTC, and SNAP23 emerged as key candidates. Pathway enrichment indicated activation of YAP and EMT signaling in high-risk patients. Bioinformatic drug-prediction analysis identified PI-103 and PLX-4720 as potential therapeutic compounds for the high-risk group. Functional experiments demonstrated that knockdown of each signature gene significantly reduced proliferation and colony formation in BLCA cell lines and consistently induced a senescence-like morphology. Conclusions: This study establishes a robust prognostic model for BLCA based on RHO GTPase cycle effector genes and highlights UACA, CLTC, and SNAP23 as potential prognostic biomarkers and promising therapeutic targets. Our findings provide a foundation for further investigation into RHO GTPase pathway effectors and their potential role in improving BLCA diagnosis and treatment. Citation Format: Weiyi Gong, Chongwen Cao, Peng Wang, Shang-Jui Wang, Akshay Sood, Lingbin Meng, Qingqing Wu, Cheryl Lee, Anil Vasdev Parwani, Jenny Li, Xuefeng Liu. A RHO GTPase pathway signature as a potential prognostic biomarker and therapeutic target in bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 3941.