Clonal dynamics and single cell transcriptomics of prostate luminal epithelial cells in homeostasis and aging

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PROJECT SUMMARY The most common prostate disorders, benign prostate enlargement and prostate cancer are associated with aging and attributed to hormonal imbalances and loss of glandular homeostasis. Given the major impact prostate pathologies have on men’s health and their significant burden on healthcare systems, it is important to further elucidate the barriers posed by normal homeostasis to deregulated clonal growth. To date, most studies focused on elucidating the identity of various stem cell prostate populations and on validating their stem cell potential in culture assays. However, a precise understanding of the cellular and population dynamics at play in adult prostate homeostasis, and how its fine balances change with aging and contribute to age-related cellular hyperproliferations, has not emerged so far. Advances in this area would be extremely beneficial for identifying deregulated prostate populations in aged tissues and for designing prophylactic therapies. In preliminary studies, using in vivo lineage-tracing and single cell transcriptomics, I uncovered a “luminal intermediate” transcriptional state (LumI) with unique Wnt/p63 signaling which constitutes a great portion of the cancer cell populations expanding in early stages of tumorigenesis. In the F99 phase of the proposal, I will investigate the LumI cell state as the preferred cell of origin in cancer models and the underlying growth program controlled by Wnt signaling and p63. Specifically, I will employ functional organoid assays to investigate the role of Wnt signaling in promoting LumI cell growth in vitro and delineate the effects of eliminating the Wnt/p63 signaling in vivo. In the K00 phase of the proposal, I will leverage my methods and generate new mouse models to delineate the cellular level heterogeneity and growth patterns in adult and aged prostate luminal layer and explore the underlying molecular regulatory mechanisms. Specifically, I will utilize innovative mathematical modeling to integrate the clonal data obtained from genetic lineage tracing to characterize the modes of adult and aging homeostatic growth adopted by prostate cells. I will also generate a novel mouse model: Nkx3.1CreERT2/+-Confetti-CARLIN mouse for simultaneous in vivo lineage tracing and barcoding which will provide increased lineage ancestry resolution. Single cell RNAseq and Single cell ATACseq will be used to assess cellular states and uncover the dynamic molecular heterogeneity of prostate luminal cells in the lineage tracing mouse model. The K00 Aim will provide a comprehensive functional map of luminal prostate cells in adult and aging prostate and identify lineages and master regulator genes associated with luminal clones. Taken together, my studies will provide a comprehensive understanding of population growth dynamics in the luminal layer of prostate tissue and may lead to identification of novel therapeutic targets for age-related prostate hyperproliferative disorders.