Abstract A085: A luminal intermediate cell state maintains long-term prostate homeostasis and contributes to tumorigenesis

Abstract

Cellular heterogeneity poses tremendous challenges for developing cell-targeted therapies and biomarkers of clinically significant prostate cancer. The origins of this heterogeneity within the cellular complexities of normal adult and aging tissue remain unknown leaving important cellular states and transcriptional programs that allow the expansion of malignant clones in early cancer unidentified. These unresolved questions hamper the development of novel therapies designed to block the deregulated proliferation of prostate epithelial cells. To define cell states that contribute to early cancer development, we performed in vivo lineage tracing with multicolor reporters, whole organ mapping and single cell transcriptomics of normal and malignant prostate from genetically-engineered mouse models. We show here that the long-term luminal homeostasis is maintained by multiple clones with various fitness levels. Long-term clonal expansions are enabled by a luminal transcriptional state harboring basal markers (Luminal Intermediate, LumI) and controlled by Wnt/p63 signaling. Moreover, LumI cells greatly expand during early stages of tumorigenesis in several mouse models of prostate cancer. Specific genetic ablation of p63 from luminal cells in vivo decreases clonal activity in homeostasis and reduces the formation of aggressive clones in prostate tumor models. Finally, the LumI cells and Wnt signaling appear to significantly increase in human aging prostate and prostate cancer samples, highlighting the importance of this hybrid cell state for human pathologies with potential translational impact. Our models reveal a continuity of this cell state from normal homeostasis to aging and early cancer with specific alterations at each stage. Understanding how the luminal intermediate cell state is regulated in homeostasis and deregulated in hyperproliferative contexts is crucial for the development of prognostic markers and new therapeutic interventions for prostate diseases. Citation Format: Fu Luo, Lara F. Tshering, Karis Tutuska, Mariola Szenk, Diana Rubel, James G. Rail, Savanah Russ, Jingxuan Liu, Alice Nemajerova, Gábor Balázsi, Flaminia Talos. A luminal intermediate cell state maintains long-term prostate homeostasis and contributes to tumorigenesis [abstract]. In: Proceedings of the AACR Special Conference: Advances in Prostate Cancer Research; 2023 Mar 15-18; Denver, Colorado. Philadelphia (PA): AACR; Cancer Res 2023;83(11 Suppl):Abstract nr A085.