Single-Cell Profiling of Murine Bladder Cancer Identifies Sex Specific Transcriptional Signatures with Prognostic Relevance

Bladder cancer (BLCA) is more common in men but more aggressive in women. A common model used to study sex-based differences in cancer biology is murine BLCA generated by N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN). While tumors in this model have been profiled, these profiles provided limited information on the tumor microenvironment. Hence, we applied single-cell RNA sequencing to characterize cell type specific transcriptional differences between male and female BBN induced tumors and then studied their human relevance. We found proportion and gene expression differences in the epithelial and non-epithelial subpopulations between male and female tumors. Of translational importance, expression of several genes was found to predict sex specific survival in several human BLCA datasets. We also noted a male biased CD8 T cell exhaustion program in this model that correlates highly with androgen receptor activity. Our study identified novel and clinically relevant sex specific transcriptional signatures and validates the relevance of the BBN model for studying sex differences in human BLCA. This work highlights the importance of considering sex as a biological variable in cancer marker development. Single cell RNA-sequencing of mouse bladder tissue following BBN treatment for 6 months (n=20) pooled into 10 samples