Abstract 4733: Effect of KDM6A mutation in bladder cancer

As of 2020, bladder cancer is the tenth most common cancer in the world, with a heavier toll exerted on males. Its higher tumor recurrence and progression rates cause major treatment challenges. One of the most frequent mutations in bladder cancer is in lysine-specific demethylase 6A (KDM6A). This gene encodes for ubiquitously transcribed tetratricopeptide repeat on chromosome X (UTX), which catalyzes the demethylation of di- and tri- methylated histones H3 lysine 27 and works as part of “COMPASS-LIKE” protein complexes to coordinate many transcriptional processes. The molecular basis for how KDM6A mutations promote carcinogenesis is still under investigation. In this study, we use single-cell RNA sequencing data from bladder cancers with and without KDM6A mutations in both human and mice to examine the effects of KDM6A mutations on the cellular composition and gene expression of tumor and normal bladders. In mice without tumors, KDM6A mutations seem to correlate with enrichment of macrophages in the bladder tissue microenvironment. The opposite is true, however, in the presence of tumors, as there were not only more macrophages but also more dendritic cells in wildtype mice. This pattern was also observed in human, suggesting differences in immune infiltrates in the tumor microenvironment are part of the phenotype of KDM6A mutation. Lastly, KDM6A mutations may also impact urothelial cell states at baseline, as KDM6A KO mouse bladders contain higher proportions of intermediate cell populations compared with their wildtype counterparts. Together, these observations contribute to a better understanding of the role KDM6A plays in bladder cancer. Citation Format: Ninh B. Le, Hong Qiu, Emily E. Fink, Surbhi Sona, Angela H. Ting, Byron H. Lee. Effect of KDM6A mutation in bladder cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4733.