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Background: Evaluating the complex interplay of cell types in the tissue microenvironment is critical to understanding the origin and progression of diseases in the prostate and potential opportunities for intervention. Mouse models are an essential tool to investigate the molecular and cell-type-specific contributions of prostate disease at an organismal level. While there are well-documented differences in the extent, timing, and nature of disease development in various genetically engineered and exposure-based mouse models in different mouse strains and prostate lobes within each mouse strain, the underlying molecular phenotypic differences in cell types across mouse strains and prostate lobes are incompletely understood., Methods: In this study, we used single-cell RNA-sequencing (scRNA-seq) methods to assess the single-cell transcriptomes of 6-month-old mouse prostates from two commonly used mouse strains, friend virus B/NIH jackson (FVB/NJ) (N = 2) and C57BL/6J (N = 3). For each mouse, the lobes of the prostate were dissected (anterior, dorsal, lateral, and ventral), and individual scRNA-seq libraries were generated. In situ and pathological analyses were used to explore the spatial and anatomical distributions of novel cell types and molecular markers defining these cell types., Results: Data dimensionality reduction and clustering analysis of scRNA-seq data revealed that basal and luminal cells possessed strain-specific transcriptomic differences, with luminal cells also displaying marked lobe-specific differences. Gene set enrichment analysis comparing luminal cells by strain showed enrichment of proto-Oncogene targets in FVB/NJ mice. Additionally, three rare populations of epithelial cells clustered independently of strain and lobe: one population of luminal cells expressing Foxi1 and components of the vacuolar ATPase proton pump (Atp6v0d2 and Atp6v1g3), another population expressing Psca and other stem cell-associated genes (Ly6a/Sca-1, Tacstd2/Trop-2), and a neuroendocrine population expressing Chga, Chgb, and Syp. In contrast, stromal cell clusters, including fibroblasts, smooth muscle cells, endothelial cells, pericytes, and immune cell types, were conserved across strain and lobe, clustering largely by cell type and not by strain or lobe. One notable exception to this was the identification of two distinct fibroblast populations that we term subglandular fibroblasts and interstitial fibroblasts based on their strikingly distinct spatial distribution in the mouse prostate., Conclusions: Altogether, these data provide a practical reference of the transcriptional profiles of mouse prostate from two commonly used mouse strains and across all four prostate lobes., (© 2022 Wiley Periodicals LLC.)

Background: Liver metastasis is not uncommon in men with metastatic castration-resistant prostate cancer (mCRPC), estimated at ~20% to 60% of advanced late-stage patients. Liver and other visceral metastases are associated with worse overall survival. Recent evidence suggests the frequency of visceral metastases may be increasing for reasons that are unclear but may be related to selective pressures induced by modern therapies, including second-generation antiandrogen receptor signaling inhibitors such as enzalutamide and abiraterone. Consequently, robust models to study the pathobiology of prostate cancer liver metastases and their response to therapy are urgently needed., Methods: Hemi-spleen injection of human (LN95, PC3, VCaP, and MDA-PCa-2b) or syngeneic (Myc-CaP) prostate cancer cells (1 × 10 6 ) was performed to seed liver metastases via the splenic vessels. Plasma levels of prostate-specific antigen (PSA) were monitored longitudinally in human androgen receptor-positive (AR+) models. Immunohistochemical staining of AR and HoxB13 was performed to document the prostatic origin of hepatic lesions., Results: LN95, PC3, and Myc-CaP produced distinct liver micrometastases that progressed to macrometastases by ~2 to 4 weeks postinoculation, while inoculation of MDA-PCa-2b and VCaP only produced occasional micrometastases and seeding of individual cells adjacent to blood vessels, respectively, at the time points analyzed. All lesions are characterized by positive staining for nuclear AR and/or the prostate-specific differentiation marker HoxB13 depending on the model. Circulating PSA levels are strongly correlated with overall tumor burden in mice seeded with LN95. Histologic micrometastases and low levels of circulating PSA are detected in mice seeded with MDA-PCa-2b at ~60 days postinoculation, but no circulating PSA was detected in animals inoculated with VCaP up to ~75 days despite the presence of rare AR+ cells in the liver., Conclusion: The studies reported herein establish intrasplenic injection as a robust model of mCRPC liver metastasis. In addition, circulating PSA was validated as a noninvasive biomarker to longitudinally monitor overall tumor burden when using PSA+ models. Therefore, this model can be used to interrogate the pathophysiology of prostate cancer liver metastases, the microenvironmental factors permissive to such growth, immunologic variables, and the response of hepatic lesions to therapy., (© 2020 Wiley Periodicals LLC.)

Prostate-specific membrane antigen (PSMA), also known as glutamate carboxypeptidase II (GCPII), is highly overexpressed in primary and metastatic prostate cancer (PCa). This has led to the development of radiopharmaceuticals for targeted imaging and therapy under current clinical evaluation. Despite this progress, the exact biological role of the protein in prostate cancer development and progression has not been fully elucidated. This is in part because the human PSMA and mouse PSMA (mPSMA) have different patterns of anatomical expression which confound study in the most widely utilized model organisms. Most notably, mPSMA is not expressed in the healthy murine prostate. Here, we reveal that mPSMA is highly upregulated in the prostate adenocarcinoma of the spontaneous Hi-Myc mouse model, a highly accurate and well characterized mouse model of prostate cancer development. Antibody detection and molecular imaging tools are used to confirm that mPSMA is expressed from early prostatic intraepithelial neoplasia (PIN) through adenocarcinoma., (© 2019 The Authors. The Prostate Published by Wiley Periodicals, Inc.)

Introduction: By regulating cell fate, proliferation, and survival, Notch pathway signaling provides critical input into differentiation, organization, and function of multiple tissues. Notch signaling is also becoming an increasingly recognized feature in malignancy, including prostate cancer, where it may play oncogenic or tumor suppressive roles., Methods: Based on an electronic literature search from 2000 to 2013 we identified, summarized, and integrated published research on Notch signaling dynamics in prostate homeostasis and prostate cancer., Results: In benign prostate, Notch controls the differentiation state and architecture of the gland. In prostate cancer, similar features correlate with lethal potential and may be influenced by Notch. Increased Notch1 can confer a survival advantage on prostate cancer cells, and levels of Notch family members, such as Jagged2, Notch3, and Hes6 increase with higher cancer grade. However, Notch signaling can also antagonize growth and survival of both benign and malignant prostate cells, possibly through antagonistic effects of the Notch target HEY1 on androgen receptor function., Discussion: Notch signaling can dramatically influence prostate development and disease. Determining the cellular contexts where Notch promotes or suppresses prostate growth could open opportunities for diagnostic and therapeutic interventions., (© 2014 Wiley Periodicals, Inc.)