The Prostate

ContextSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cellular entry is facilitated by transmembrane protease serine 2 (TMPRSS2), which is regulated by the androgen receptor (AR). Androgen deprivation therapy (ADT), widely used in prostate cancer treatment, may potentially modulate TMPRSS2 expression, affecting SARS-CoV-2 infection susceptibility and severity. ObjectiveTo evaluate the impact of ADT on pulmonary TMPRSS2 expression in prostate cancer patients and analyze differences in expression patterns associated with specific ADT regimens. DesignWe examined TMPRSS2 immunohistochemical expression in lung tissue from 20 consecutive autopsy cases of men with prostate cancer (6 receiving ADT at time of death), compared with non-ADT prostate cancer patients and age-matched women controls. Histoscores were calculated by assessing percentage and intensity of pneumocyte TMPRSS2 expression. ResultsProstate cancer patients receiving ADT showed significantly reduced pulmonary TMPRSS2 expression compared to non-ADT patients (mean histoscores: 152.7 vs. 225.0, p=0.037) and age-matched women controls (mean histoscores: 152.7 vs. 238.0, p=0.024). Direct AR antagonists (apalutamide, bicalutamide) produced more pronounced TMPRSS2 suppression than GnRH modulators or androgen biosynthesis inhibitors. No significant correlation was observed between TMPRSS2 expression and Gleason score, PSA levels, or underlying lung pathology. ConclusionOur findings demonstrate that ADT significantly reduces pulmonary TMPRSS2 expression, with direct AR antagonists showing the strongest effect. This suggests a potential mechanistic explanation for differential COVID-19 susceptibility and provides rationale for investigating AR-targeted therapies as potential protective interventions against SARS-CoV-2 infection severity.

Androgen deprivation therapy (ADT) remains a cornerstone in the treatment of prostate cancer (PCa), yet most tumors eventually develop resistance. Murine models are widely used to study PCa progression and ADT response, but a detailed understanding of the prostates biological response to androgen deprivation in these models is lacking. Here, we present a comprehensive spatiotemporal analysis of cellular and transcriptional dynamics in the mouse prostate following orchiectomy (ORX)-induced androgen deprivation. We observed progressive involution across all prostate lobes (dorsal, ventral, lateral, and anterior) and distinct lobe-specific temporal gene expression changes post-ORX. Immune cell infiltration markedly increased over time, highlighting a shift in the prostates cellular landscape. Single-cell RNA sequencing uncovered a previously undescribed fibroblast subtype--termed ORX-induced fibroblast (OIF)-- characterized by high expression of Wnt2, Rorb, and Wif1, with distinct spatial localization. Pathway analysis revealed upregulation of amide and peptide binding functions, alongside suppression of peptidase and endopeptidase activity. Furthermore, dynamic changes in ligand-receptor interactions across lobes underscored the evolving intercellular communication in the post-ORX prostate. By integrating spatial transcriptomics with single-cell profiling, our study generates a high-resolution atlas of the murine prostates response to androgen deprivation. These findings provide a foundational resource for interpreting ADT responses in preclinical models of PCa.

Benign prostatic hyperplasia (BPH) is a non-neoplastic proliferative disease producing lower urinary tract symptoms related to the enlarged prostate. BPH is pathologically characterized by hyperplastic growth in both epithelial and stromal compartments. Androgen signaling is essential for prostate function and androgen blockade is the second-line medical therapy to relieve symptoms of BPH. Here we examined the prostates of probasin promoter-driven prolactin (Pb-PRL) transgenic mice, a robust model of BPH that spontaneously develops prostate enlargement, to investigate prostate regression in response to surgical castration. Serial ultrasound imaging demonstrated very uniform self-limited growth of Pb-PRL prostate volume that is consistent with the benign, limited cellular proliferation characteristic of BPH and that contrasts with the highly variable, exponential growth of murine prostate cancer models. Castration elicited only a partial reduction in prostate volume, relative to castration-induced regression of the normal prostate gland. The anti-androgen finasteride induced a diminished reduction of Pb-PRL prostate volume versus castration alone. The limited extent of Pb-PRL mouse prostate volume regression correlated with the initial volume of the stromal compartment, suggesting a differential sensitivity to androgen withdrawal of the epithelial and stroma compartments. Indeed, two-dimensional morphometric analyses revealed a distinctly reduced rate of regression for the stromal compartment in Pb-PRL mice. The myofibroblast component of the Pb-PRL prostate stroma appeared normal, but contained more fibroblasts and extracellular collagen deposition. Like normal prostate, the rate of regression of the Pb-PRL prostate was partially dependent on TGF{beta} and TNF signaling, but unlike the normal prostate, the extent of castration-induced regression was not affected by TGF{beta} or TNF blockade. Our studies show that androgen deprivation can effectively reduce the overall volume of hyperplastic prostate, but the stromal compartment is relatively resistant, suggesting additional therapies might be required to offer an effective treatment for the clinical manifestations of BPH.

ABSTRACT/SUMMARYThe cellular composition and disease susceptibilities of the distinct zones of the human prostate remain incompletely understood. Through extensive single-cell RNA sequencing (scRNA-seq) of benign regions from prostatectomy specimens, we identified a basal cell population expressing WIF1, VCAN, and NRG1, among other genes, that was significantly enriched in the transition zone (TZ). Benign prostatic hyperplasia (BPH) is a common condition that causes widespread morbidity and is nearly exclusively localized to the TZ. Analysis of previously published scRNA-seq datasets further confirmed that WIF1+ basal cells were significantly enriched in BPH compared to normal prostate. Pathway and cell-cell communication analyses revealed that this basal subtype is associated with programs related to cell proliferation, epithelial-mesenchymal transition (EMT), angiogenesis, and hormone response. Together, the molecular signature, zonal distribution, and pathway enrichment suggest that TZ-enriched WIF1+ basal cells may contribute to BPH pathogenesis by promoting epithelial and stromal remodeling.

PurposeProstate cancer is the most commonly diagnosed neoplasm in American men. Although existing biomarkers may detect localized prostate cancer, additional strategies are necessary for improving detection and identifying aggressive disease that may require further intervention. One promising, minimally invasive biomarker is cell-free DNA (cfDNA), which consist of short DNA fragments released into circulation by dying or lysed cells that may reflect underlying cancer. Here we investigated whether differences in cfDNA concentration and cfDNA fragment size could improve the sensitivity for detecting more advanced and aggressive prostate cancer. Materials and MethodsThis study included 268 individuals: 34 healthy controls, 112 men with localized prostate cancer who underwent radical prostatectomy (RP), and 122 men with metastatic castration-resistant prostate cancer (mCRPC). Plasma cfDNA concentration and fragment size were quantified with the Qubit 3.0 and the 2100 Bioanalyzer. The potential relationship between cfDNA concentration or fragment size and localized or mCRPC prostate cancer was evaluated with descriptive statistics, logistic regression, and area under the curve analysis with cross-validation. ResultsPlasma cfDNA concentrations were elevated in mCRPC patients in comparison to localized disease (OR5 ng/mL = 1.34, P = 0.027) or to being a control (OR5 ng/mL = 1.69, P = 0.034). Decreased average fragment size was associated with an increased risk of localized disease compared to controls (OR5bp = 0.77, P = 0.0008). ConclusionThis study suggests that cfDNA concentration and average cfDNA fragment size may provide a quick, cost-effective approach to help determine which patients will benefit most from further screening and/or disease monitoring to help improve prostate cancer outcomes.

Benign prostatic hyperplasia (BPH) is the most prevalent urologic disease in men aged over 50 years. However, the molecular mechanisms that drive BPH pathophysiology remain elusive. In this study, we integrated bioinformatic and experimental analyses of human BPH to identify TIAM1-RAC1 signaling pathway as a promising candidate for a molecular-based approach for BPH therapy. First, elevated TIAM1 expression in a BPH transcriptomic signature that was generated from the analysis of RNA-seq data from three independent BPH patient cohorts was validated at the protein level in a fourth patient cohort. Additional bioinformatic analyses of the BPH transcriptomic signature pointed to TIAM1-RAC1 pathway as the potential lead therapeutic pathway; and NSC23766 - a small molecule inhibitor of TIAM1 signaling - as a developmental lead compound for BPH therapy. Next, a proof-of-concept pharmacological approach of TIAM1-RAC1 inhibition in human prostatic cells using NSC23766 resulted in attenuated organoid budding and branching - a developmental program associated with prostatic nodule formation and BPH pathogenesis. Finally, shRNA-based genetic knock-down of TIAM1 in human prostatic cells led to a reduction in budding and branching phenotypes thereby phenocopying the effects of NSC23766. Together, our observations implicate elevated TIAM1 as a driver of budding and branching in BPH, and our studies pave the way for TIAM1-RAC1 based targeted approach for the treatment of the disease.

Background and ObjectivesCD276 (B7-H3) has recently emerged as a promising presumptive immune checkpoint inhibitor (ICI) and a potential antibody-drug conjugate (ADC) target for prostate cancer (PCa). We evaluated B7-H3 and 15 other clinically relevant ADC and ICI targets for expression at the RNA and protein level across the PCa continuum--hormone-sensitive, castration-resistant, and neuroendocrine. MethodsCCLE data analysis and western blot experiments were performed for quantifying RNA and protein expression variability across PCa cell lines. Inter- and intratumoral heterogeneity was evaluated by integrating single-cell RNA sequencing data across 595k cells and 102 patients, spanning the disease continuum. AR and B7-H3 knockouts of PCa cell lines were developed and investigated using R1881 and Enzalutamide to elucidate the AR-CD276 signaling pathway through qRT-PCR and flow cytometry. Key FindingsB7-H3 showed high expression in tumor and myeloid cells (tumor microenvironment - TME), lowest heterogeneity across all ADC and ICI targets, and was negatively regulated by androgen signaling. LimitationsFurther validation of ADC and ICI target protein expression in human samples and more exhaustive exploration of the AR-CD276 signaling cascade is required. ConclusionB7-H3 demonstrates the least susceptibility to selective pressure due to its stable expression across PCa disease states. Clinical ImplicationsB7-H3 represents an important ADC target for PCa due to its potential to minimize drug resistance and likely ability to be a valid target across the prostate cancer continuum. Additionally, its expression in myeloid cells supports a dual role as an ICI, further enhancing its therapeutic relevance. Graphical AbstractDiscovery of optimal checkpoints and antibody drug conjugates (ADCs) in Prostate Cancer (PCa). O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=150 SRC="FIGDIR/small/632253v1_ufig1.gif" ALT="Figure 1"> View larger version (69K): org.highwire.dtl.DTLVardef@1af1115org.highwire.dtl.DTLVardef@8a9d70org.highwire.dtl.DTLVardef@6659aeorg.highwire.dtl.DTLVardef@189e200_HPS_FORMAT_FIGEXP M_FIG C_FIG Patient SummaryIn this study, we demonstrate that prostate cancer expresses high amounts of a cell surface protein called B7-H3 both when first diagnosed and throughout various stages of metastatic disease. Furthermore, we demonstrate a clear and yet to be fully resolved cross-talk between B7-H3 and the androgen signaling pathway central to prostate cancer development. We conclude that B7-H3 is therefore a highly promising therapeutic cell surface protein expressed by prostate cancer due to its stable expression potentially leading to low selective pressure and reduced drug resistance--thereby having significant implications for clinical trial design and patient inclusion considerations. Advancing PracticePCa is a highly heterogeneous disease with an increasingly wide treatment landscape, governed by various factors including clinical covariates, histopathological features, and molecular factors. B7-H3 has recently emerged as a promising clinical target for immunotherapy in the localized setting and antibody drug targeting in the metastatic setting. Despite the clinical significance, B7-H3 expression has not yet been thoroughly evaluated against other clinically relevant immune checkpoint and antibody drug targets, especially along the continuum of PCa treatment stages--hormone sensitive, castration resistant, and neuroendocrine. To our knowledge, this is the first study to characterize B7-H3 in this continuum using representative cell lines and the largest collection of PCa patient single cell sequencing data yet assembled in the literature, thus accounting for the substantial heterogeneity across PCa disease states as well as between datasets. Take Home MessageThis article explores the therapeutic relevance of clinical stage ADC targets and immune checkpoints for Prostate Cancer (PCa). We show that B7-H3 is a highly promising therapeutic candidate for PCa due to its stable expression across various disease states.

Telomeres, the repetitive DNA elements at chromosome ends, are pivotal for maintenance of genome integrity. Previous studies from our group and others have highlighted the translational potential of tissue-based telomere length measurements to address the clinical challenge of improving diagnosis, individualized risk stratification, and accurate prognostication of different diseases. Here, we describe a high-throughput method that quantitates cell type-specific telomere lengths at a single cell level in archival tissues from patient cohorts for research on prognosis. This approach is based on telomere-specific fluorescence in situ hybridization (FISH) combined with multiplex immunostaining for cell type-specific antibodies, followed by semi-automated slide scanning and multi-channel acquisition of fluorescent images using the TissueFAXS Plus microscopy workstation and TissueQuest software (TissueGnostics). Here, we demonstrate that this method is sufficiently robust and reproducible to detect biologically significant differences in telomere lengths in archived tissues either on whole slides or sampled across tissue microarrays, which is essential when assessing prognosis in large patient cohorts.

BackgroundSpatial and single-cell transcriptomics have revealed significant heterogeneity in tumor and normal tissues. Each approach has its advantages: The Visium platform for spatial transcriptomics (ST) offers lower resolution than single-cell analysis, but histology enables the examination of cell morphology, tissue architecture, and potential cell-cell interactions. Single-cell transcriptomics (SC) provides high resolution, but manual cell-type annotation depends on incomplete scientific knowledge from heterogeneous experiments. When investigating poorly defined phenomena, such as the transition from normal tissue to cancer and metaplasia, researchers might overlook critical and unexpected findings in downstream analysis if they rely on pre-existing annotations to determine cell types, particularly in the context of phenotypic plasticity. ResultsWe employ our deep-transfer learning framework, DEGAS, to identify benign morphology glands in normal prostate tissue that are associated with poor progression-free survival in cancer patients and exhibit transcriptional signatures of carcinogenesis and de-differentiation. We confirm this finding in an additional ST dataset and use novel published methods to integrate SC data, showing that cells annotated as cancerous in the SC data map to regions of benign glands in another dataset. We pinpoint several genes, primarily MSMB, with expression closely correlated with progression-free survival scores, which are known markers of de-differentiation, and attribute their expression specifically to luminal epithelia, which are the presumed origin of most prostatic cancers. DiscussionOur work shows that morphologically normal epithelia can have transcriptional signatures like that of frank cancer, and that these tissues are associated with poor progression-free survival. We also highlight a critical gap in single-cell workflows: annotating continuous transitional phenomena like carcinogenesis with discrete labels can result in incomplete conclusions. Two approaches can help mitigate this issue: Tools like DEGAS and Scissor can provide a disease-association score for SC and ST data, independent of cell type and histology. Additionally, researchers should adopt a bidirectional approach, transferring histological labels from ST data to SC data using tools like RCTD, rather than only using SC cell-type assignments to annotate ST data. Employed together, these methods can offer valuable histology and disease-related information to better define tissue subtypes, especially epithelial cells in the process of carcinogenesis. ConclusionsDEGAS is a vital tool for generating clinically-oriented hypotheses from SC and ST data, which are heterogeneous, information-rich assays. In this study, we identify potential signatures of carcinogenesis in morphologically benign epithelia, which may be the precursors to cancer and high-grade pre-malignant lesions. Validating these genes as a panel may help identify patients at high risk for future cancer development, recurrence, and assist researchers in studying the biology of early carcinogenesis by detecting metaplastic changes before they are morphologically identifiable.

Castration-resistant prostate cancer represents a continuum of phenotypes, including tumors with high levels of androgen receptor (AR) expression and activity and those which do not express AR and rely on alternative pathways for survival. The process by which AR-positive prostate cancer cells and tumors lose AR expression and acquire neuroendocrine features is referred to as neuroendocrine differentiation. Numerous therapies and exposures have been demonstrated to induce neuroendocrine differentiation in vitro, including the pro-inflammatory cytokine, interleukin 1 beta (IL-1{beta}), encoded by the gene IL1B. The purpose of our studies was to determine the relationship between the expression and activity of AR in relationship to IL-1{beta} and IL1B in prostate cancer. We performed analysis of de-identified human clinical data and generated prostate cancer cell lines with overexpression or knockout of IL1B. In primary prostate cancer, higher expression of IL1B predicts longer time to biochemical recurrence. In metastatic castration-resistant prostate cancer, IL1B expression is decreased and inversely correlates with AR and AR-target gene expression and AR activity, while positively correlating with the neuroendocrine prostate cancer (NEPC) score and neuroendocrine marker gene expression. In vitro, we report that AR-positive castration-resistant prostate cancer cells (C4-2B, 22Rv1) secrete IL-1{beta}, and knockout of IL1B in these cells results in increased AR activity, in the presence and absence of dihydrotestosterone (DHT). Importantly, knockout of IL1B prevented AR attrition during androgen-deprivation. Taken together, our studies demonstrate that loss of IL1B in AR-positive castration-resistant prostate cancer cells can increase and maintain AR activity in the absence of androgens, suggesting another potential mechanism of high AR activity in castration-resistant prostate cancer.

BackgroundProstate cancer is a complex and heterogeneous disease with multiple tumor foci, each potentially harboring distinct driver molecular aberrations. This complexity poses challenges to effective management. We took an innovative approach to gain a comprehensive understanding of the genetic underpinnings of each tumor focus and avoid overlooking more minor yet clinically significant foci. Instead of relying solely on a systematic sampling of dominant foci, we conducted molecular analysis on whole-mount radical prostatectomy specimens. Our study aimed to find distinct molecular subsets of prostate cancer and assess their correlation with clinical outcomes, focusing on Caucasians (CA) and African Americans (AA). MethodWe randomly selected 2201 whole-mount radical prostatectomy cases, with 1207 (54.8%) from CA and 994 (45.1%) from AA patients evaluated for a 5-year biochemical recurrence-free survival rate (BCR). Of these 2201 cases, 834 (463 -56% were from CA and 371 -44% from AA patients) were subjected to molecular analysis using dual immunohistochemistry (IHC) for ERG and SPINK1, along with dual RNA in-situ hybridization (RNA-ISH) for ETV1 and ETV4 to evaluate tumor molecular heterogeneity on whole-mount specimens. The Chi-squared test examined racial disparities in aberrant oncogene expression. To assess BCR-free survival, we employed the Kaplan-Meier method and Cox-PH models for patients with distinct molecular subsets of prostate cancer. Additionally, Gleason Grade groups of prostate biopsies were summarized using a spaghetti plot and compared using linear mixed models. ResultsAnalysis of the 2201 cases revealed that AA with localized prostate cancer behaved differently with better 5-year BCR-free survival than CA after radical prostatectomy (AA: 0.82, 95% CI 0.80-0.85; CA: 0.71, 95% CI 0.68-0.75; p<.001). Molecular profiling of whole-mount specimens from 834 cases revealed that 16.4%, 58.4%, 21.7%, and 3.5% of patients with localized prostate cancer expressed none, one, two, and three of the four oncogenes, respectively. This finding identified new molecular subsets of prostate cancer with more than one driver mutation in a mutually exclusive manner within the multifocal disease. ERG and SPINK1 expression showed a negative correlation (p<.001). Notably, AA patients exhibited a lower incidence of ERG (38.8% vs. 60.3%) but a higher incidence of SPINK1 (63.3% vs. 35.6%) than CA patients. The incidences of ETV1 (9.4% vs. 9.3%) and ETV4 (4.6% vs. 3.9%) were not statistically significant between the two racial groups. However, significantly, ETV1 expression was associated with worse BCR-free survival in CA patients (hazard ratio [HR]=2.36, 95% CI 1.22-4.57, p=.02), while ETV4 expression was linked to worse BCR-free survival in AA patients (HR=2.65, 95% CI 1.15-6.09, p=.02). Moreover, ETV4 expression was associated with regional lymph node metastasis in AA patients (odds ratio [OR]=5.14, 95% CI 1.3-17.4, p=.01) but not in CA patients (OR=0.60, 95% CI 0.03-3.17, p=.63) at the time of radical prostatectomy. Additionally, in patients who underwent multiple biopsies before radical prostatectomy, the Gleason Grade group increased over time in AA patients (0.25 per year, p<.001) but remained unchanged in CA patients. ERG expression was associated with a lower Gleason Grade group (-0.20, p=.03), while ETV4 expression was linked to a higher Gleason Grade (0.54, p=.01). ConclusionsOur study reveals that AA with localized prostate cancer behaves differently and has better BCR-free survival than CA after radical prostatectomy, even after adjusting for known prognostic factors. Identification of new molecular subsets of prostate cancer with more than one ETS gene fusion within a multifocal prostate shows significant molecular heterogeneity between localized prostate cancer in CA and AA patients. Importantly, given the association of ETV1 and ETV4 expression with worse BCR-free survival in CA and AA, respectively, ETV1 and ETV4 emerge as potential prognostic markers, offering insights for clinical practice to predict prostate cancer recurrence after radical prostatectomy. Identification of new molecular subsets of prostate cancer with more than one ETS gene fusion and SPINK1 in a mutually exclusive pattern indicates the clonal origin of independent tumor foci, which is a rare and unique phenomenon in prostate cancer hitherto unidentified.

Cell line experiments arguably remain the most used tool in preclinical cancer research, despite their limitations. With almost 95% drugs entering human trials failing, and up to 90% preclinical research failing before even being tested in humans, we must shift the pre-clinical paradigm. A range of in silico, in vitro, in vivo and ex vivo approaches are gaining popularity, with the aim of potentially replacing cell line use. However, we cannot ignore the plethora of historical data from cell lines, nor write off their future use- especially within advanced bioengineered models. Therefore, we must question if and how cell lines hold clinical relevance. This study evaluates the clinical characteristics of 46 prostate cancer cell lines against worldwide data and investigates the biological features of seven cell lines in depth, comparing them to over 10,000 well characterised human cases from 24 studies in nine countries. Clinical features compared included age, ethnicity, Gleason grade, cancer type, treatment history and multiomics variables included mutations, copy number alterations, structural variants, microsatellite instability, mRNA and protein expression, and tumour mutational burden. We found that the most used cell lines accurately represent a minute proportion of prostate cancer patients. Furthermore, we recommend a pipeline for tailoring selection of clinically relevant cell lines with the ultimate aim of increasing the scientific methodology behind choosing a cell line.

BackgroundAVODART After Radical Therapy For Prostate Cancer Study (ARTS) reported dutasteride reduced PSA doubling (PSADT) at two years by 66% and disease progression by 59%. The durability of the cancer control is unknown. ObjectiveExplore the impact of dutasteride on PSADT and time to progression in men with PSA-only recurrent disease. Design, Setting and ParticipantsRetrospective examination of the impact of dutasteride on PSA kinetics and time to progression with PSA-only recurrent prostate cancer. InterventionDutasteride daily. Outcome, Measurement and Statistical AnalysisChange in PSA over time was determined by linear regression of natural log of PSA versus time. The slope of that curve was used as a measure of exponential PSA progression. Impact of dutasteride on slope was analyzed using Wilcoxon signed-rank two-sided test. Time to progression was analyzed using Kaplan-Meier, univariant and multivariant Cox regression. Results and LimitationCompared to men with BPH, patients showed little change in PSA during the first 3 months. Thereafter, the PSA resumed an exponential increase. PSADT was 10.3 months pre dutasteride and 24.8 months post dutasteride. Multivariant analysis showed a strong correlation between post dutasteride PSA kinetics and time to progression, with close to 50% relapse free at 10 years. Post-dutasteride, patients with PSADT >9 months had significantly better survival. ConclusionsDutasteride slows PSADT in PSA-only recurrent prostate cancer. This decline correlated with time to disease progression with close to 50% progression free at 10 years. Patient SummaryMen with PSA-only recurrent prostate cancer on dutasteride experience a significant drop in the rate at which the PSA increases. If the PSA does not double between months 3-12, they are likely to remain free of metastases for many years.

BackgroundHomozygous biallelic inactivation of CDKN1B is thought to be rare in cancer. Herein we evaluate the prevalence of intratumoral (subclonal) complete p27 protein loss (IPPL) in primary prostate cancer. Experimental DesignWe used immunohistochemistry (IHC) for p27 in a large cohort of whole tissue sections from radical prostatectomy (n=412) and metastases from self-identified African American (AA) and European American (EA) individuals. IPPL was evaluated alongside CDKN1B mRNA in-situ hybridization and next generation sequencing of laser captured cancer regions. Cox proportional hazards analyses assessed the association of IPPL with biochemical recurrence and development of metastases after radical prostatectomy. ResultsIPPL was detected in 18.1% of AA versus 12.2% of EA cases and was tightly correlated with CDKN1B mRNA loss and biallelic genomic loss. IPPL was associated with [&ge;]pT3 pathologic stage and pN1 disease, however these associations were only significant among AA participants. IPPL was further associated in both univariate and multivariate analyses with the development of biochemical recurrence and metastasis after primary treatment, specifically in AA individuals. The prevalence of p27 genomic alterations in metastatic disease is higher than that of primary prostate cancer in publicly available datasets as well as our analysis of autopsy cases via IHC, indicating that complete p27 loss may be selected for in metastatic disease. ConclusionsSubclonal biallelic loss of CDKN1B resulting in complete p27 protein loss is one of the most commonly occurring biallelic tumor suppressor genomic alterations in primary prostate cancer, and could contribute to worse prostate cancer outcomes, specifically in AA males.

Castration resistant prostate cancer (CRPC) is an advanced form of prostate cancer associated with loss of androgen receptor activity and resistance to AR-targeted therapies. CRPC is often associated with higher metastasis, invasion, and proliferation. Thus, theres a strong need for additional molecular markers in CRPC, and therapies that target them directly. Transcriptomic profiling of prostate cancer patients revealed an upregulated signature specific to high-grade tumors in cell cycle progression, E2F targets, G2M checkpoint, DNA repair, Aurora Kinase B, and FOXM1 pathway. Validation in a separate cohort of neuroendocrine prostate cancer patients, the most resistant and invasive form of CRPC which lacks AR expression, showed CCP signature as a dominant driver gene set for NEPC. Moreover, high expression of mRNA targets in each of these pathways is associated with poor overall survival in NEPC patients. Gene set variation analysis revealed a strong inverse correlation between AR signaling and CCP.31, set of 31 markers associated with high proliferation, and a positive correlation between CCP.31 and NEPC signature. FOXM1, a prioritized candidate in CCP is shown to be upregulated in CRPC cell lines and human clinical sections of Gleason 9 patients. GSNO, a nitric oxide donor, known for its inhibitory effect on cell proliferation and an effective inhibitor of cell cycle checkpoints, was able to reverse CCP signature both in-vitro and in-vivo. GSNO exhibits a dependence on AR signaling in-vitro by showing mild effect on CRPC clones, but successfully inhibits tumor growth of AR-null CRPC xenografts. FOXM1 is also targeted by GSNO in-vivo and in-vitro models of both CRPC and AD prostate cancer. This establishes an important link between androgen receptor status in prostate cancer and proposes nitric oxide donors as therapeutic intervention. GSNO is effective against AR-null castration resistant prostate cancer. SignificanceNitric oxide donor, S-glutathione-transferase inhibits tumor growth of castration resistant prostate cancer, regardless of androgen receptor expression status by targeting FOXM1, a critical regulator of cell cycle progression. O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY

Prostate and bladder cancers are common cancers in men. It has been speculated that the high concomitant incidence of the two cancers is due to a potential shared cause underlying both cancers. In this report, we have identified a common cause of human prostate and bladder cancers as the mutant oncoprotein GT198 (PSMC3IP). GT198 is a DNA repair factor and a steroid hormone receptor coactivator. GT198 has been previously shown to be mutated in angiogenic pericyte stem cells in solid tumor microenvironment. GT198 is also a direct protein target of chemo drugs paclitaxel and doxorubicin. Here we show, the GT198 gene is mutated with protein overexpression in tumor stroma of human prostate and bladder cancers. Affected stromal cells include angiogenic blood vessel pericyte stem cells, and vascular smooth muscle cell lineages including myofibroblasts in prostate and smooth muscle cells in bladder. In prostate cancers, GT198+ tumor stromal cells are associated with early stages of cancer with lower Gleason scores. In bladder cancers, the presence of angiogenesis and GT198+ stroma are associated with better progression-free survival in docetaxel-treated patients. Together, our evidence suggests that angiogenic pericyte stem cells are initial lesions producing a mutant stroma carrying GT198 somatic mutations. Subsequently, mutant myofibroblasts promote adenocarcinomas in prostate and mutant smooth muscle cells promote urothelial carcinomas in bladder. Chemo drugs targeting to GT198 is more effective in early stages of cancers with GT198+ stromal cells. This study supports oncoprotein GT198 as a common cause and a drug target in human prostate and bladder cancers.

Treatment-emergent neuroendocrine prostate cancer (t-NEPC) arises following androgen deprivation therapy, leading to androgen-independent growth. Although multiple factors have been shown to be necessary for neuroendocrine differentiation (NED), their sufficiency has not been demonstrated. The prostate and colorectum share a common hindgut origin, and prostate neuroendocrine cell markers overlap with colorectal enteroendocrine cell (EEC) markers. Analysis of patient datasets revealed NEUROG3 amplification in both castration-resistant and neuroendocrine prostate cancers, correlating with poor survival. Because Neurogenin-3 (NEUROG3) is necessary and sufficient for EEC differentiation in the colorectum, we hypothesized that it could similarly drive NED in prostate cancer cells. A transient pulse of NEUROG3 repressed luminal identity and activated neuroendocrine programs, producing neuroendocrine cells within seven days. In summary, our findings identify NEUROG3 as a potential mediator of prostate cancer progression and establish a rapid in vitro model in which its transient activation is sufficient to initiate neuroendocrine differentiation.

Benign prostatic hyperplasia (BPH) is a prevalent age-related condition often characterized by debilitating urinary symptoms. Its etiology is believed to stem from hormonal imbalance, particularly an elevated estradiol-to-testosterone ratio and chronic inflammation. Our previous studies using a mouse steroid hormone imbalance model identified a specific increase in macrophages that migrate and accumulate in the prostate lumen where they differentiate into lipid-laden foam cells in mice implanted with testosterone and estradiol pellets, but not in sham animals. The current study focused on further characterizing the cellular heterogeneity of the prostate in this model as well as identifying the specific transcriptomic signature of the recruited foam cells. Moreover, we aimed to identify the epithelia-derived signals that drive macrophage infiltration and luminal translocation. Male C57BL/6J mice were implanted with slow-release testosterone and estradiol pellets (T+E2) and harvested the ventral prostates two weeks later for scRNA-seq analysis, or performed sham surgery. We identified Ear2+ and Cd72+ macrophages that were elevated in response to steroid hormone imbalance, whereas a Mrc1+ resident macrophage population did not change. In addition, an Spp1+ foam cell cluster was almost exclusively found in T+E2 mice. Further markers of foam cells were also identified, including Gpnmb and Trem2, and GPNMB was confirmed as a novel histological marker with immunohistochemistry. Foam cells were also shown to express known pathological factors Vegf, Tgfb1, Ccl6, Cxcl16 and Mmp12. Intriguingly, a screen for chemokines identified the upregulation of epithelial-derived Cxcl17, a known monocyte attractant, in T+E2 prostates suggesting that it might be responsible for the elevated macrophage number as well as their translocation to the lumen. Our study identified macrophage subsets that respond to steroid hormone imbalance as well as further confirmed a potential pathological role of luminal foam cells in the prostate. These results underscore a pathological role of the identified prostate foam cells and suggests CXCL17-mediated macrophage migration as a critical initiating event.

A recent study has shown that SKP2 inactivation can prevent cancer initiation by extension of total cell cycle duration without perturbing normal division, which suggests a new strategy for cancer prevention. However, direct in vivo evidence for human SKP2 on cancer initiation and prostatic microenvironment is still lacking and a prostate-specific SKP2 humanized mouse model is critical for developing prostate cancer immunoprevention approaches through targeting human SKP2. We therefore have established a prostate-specific human SKP2 (hSKP2) knock-in mouse model by a CRISPR knock-in approach. Overexpression of hSKP2, which is driven by an endogenous mouse probasin promoter, induces prostatic lesions including hyperplasia, mouse prostate intraepithelial neoplasia (mPIN), and low-grade carcinoma and increases prostate weights. Transcriptional profiling by RNA-sequencing analysis revealed significant gene expression alterations in epithelial to mesenchymal transition (EMT), extracellular matrix, and interferon signaling in the prostate of hSKP2 knock-in mice compared to wild-type mice. Single cell deconvolution showed an increase of fibroblasts population and a decrease of CD8+ T cell and B cell populations in the prostate of hSKP2-knock-in mice. Consistently with these results from the SKP2 humanized mouse, overexpression of hSKP2 in human prostate cancer PC3 cells markedly increased cell migration and invasion and induced the gene expression of EMT and interferon pathways, including FMOD, THY1, PFKP, USP18, IL15, etc. In addition, paired prostate organoids were derived from SKP2 humanized and wild-type mice for drug screening and validated by known SKP2 inhibitors, Flavokawain A and C1. Both of which selectively decrease the viability and alter the morphologies of organoids of hSKP2 knock-in rather than wild-type mice. Our studies provide a well-characterized prostate-specific hSKP2 knock-in mouse model and offer new mechanistic insights for understanding the oncogenic role of SKP2 in shaping the prostatic microenvironment during early carcinogenesis.

A diagnostic non-invasive biomarker test for prostate cancer at an early stage, with high sensitivity and specificity, would improve diagnostic decision making. Extracellular RNAs present in seminal plasma might contain biomarker potential for the accurate detection of clinically significant prostate cancer. So far, the extracellular messenger RNA (mRNA) profile of seminal plasma has not been interrogated for its biomarker potential in the context of prostate cancer. Here, we investigate the mRNA transcriptome in seminal plasma samples obtained from prostate cancer patients (n=25), patients with benign prostate hyperplasia (n=26) and individuals without prostatic disease (n=6). Seminal plasma harbors a complex mRNA repertoire that reflects prostate as its tissue of origin. The endogenous RNA content is higher in the prostate cancer samples compared to the control samples. Prostate cancer antigen 3 (PCA3), a long non-coding RNA with prostate cancer-specific overexpression, and ATP-binding cassette transporter 1 (ABCA1), known to be involved in the prostate cancer pathogenesis, were more abundant in the prostate cancer group. In addition, twelve high confidence fusion transcripts could be detected in prostate cancer samples, including the bona-fide prostate cancer fusion transcript TMPRSS2-ERG. Our findings provide proof-of-principle that the extracellular transcriptome of seminal plasma can reveal information of an underlying prostate cancer.