Interactions In Prostate Cancer Research Articles

Binding of interleukin-1 receptor antagonist to cholinergic receptor muscarinic 4 promotes immunosuppression and neuroendocrine differentiation in prostate cancer

The tumor microenvironment (TME) of prostate cancer (PCa) is characterized by high levels of immunosuppressive molecules, including cytokines and chemokines. This creates a hostile immune landscape that impedes effective immune responses. The interleukin-1 (IL-1) receptor antagonist (IL1RN), a key anti-inflammatory molecule, plays a significant role in suppressing IL-1-related immune and inflammatory responses. Our research investigates the oncogenic role of IL1RN in PCa, particularly its interactions with muscarinic acetylcholine receptor 4 (CHRM4), and its involvement in driving immunosuppressive pathways and M2-like macrophage polarization within the PCa TME. We demonstrate that following androgen deprivation therapy (ADT), the IL1RN-CHRM4 interaction in PCa activates the MAPK/AKT signaling pathway. This activation upregulates the transcription factors E2F1 and MYCN, stimulating IL1RN production and creating a positive feedback loop that increases CHRM4 abundance in both PCa cells and M2-like macrophages. This ADT-driven IL1RN/CHRM4 axis significantly enhances immune checkpoint markers associated with neuroendocrine differentiation and treatment-resistant outcomes. Higher serum IL1RN levels are associated with increased disease aggressiveness and M2-like macrophage markers in advanced PCa patients. Additionally, elevated IL1RN levels correlate with better clinical outcomes following immunotherapy. Clinical correlations between IL1RN and CHRM4 expression in advanced PCa patients and neuroendocrine PCa organoid models highlight their potential as therapeutic targets. Our data suggest that targeting the IL1RN/CHRM4 signaling could be a promising strategy for managing PCa progression and enhancing treatment responses.

Abstract 4386: Androgen hormone signaling regulates the association between the hippo pathway component YAP1 and RNA binding protein NPM1

Abstract Prostate cancer represents a major health concern for men in the United States and globally, disproportionately affecting men of African descent. Despite recent advances, the precise etiology and molecular mechanisms underpinning fatal prostate cancer in humans remain inadequately understood. RNA binding proteins (RBPs) regulate various aspects of RNA biology, and when their regulation is disrupted, they can lead to human diseases, including cancer. However, the comprehensive alterations in RBP-mRNA interactions in prostate cancer have not been explored. In this study, we investigated the dynamics of RBPs and their interactions with polyadenylated mRNA in the castration-sensitive LNCaP and castration-resistant C4-2 prostate cancer cell lines. Using an enhanced RNA interactome capture assay in combination with mass spectrometry, we discovered that LNCaP and C4-2 cells showed distinct RBP-mRNA interaction patterns in steady-state growth conditions and in response to androgen treatment. Additionally, we investigated the interplay between the oncogene Yes-associated protein 1 (YAP1) and the RNA-binding protein nucleophosmin (NPM1). We identified NPM1 as a component of the YAP1 protein complex through mass spectrometry-based proteomics. Our proximity ligation assay demonstrated that androgen signaling could regulate the interaction between YAP1 and NPM1. Also, our GST-pulldown revealed that NPM1 binds to the proline-rich domain of YAP1 in LNCaP cells, while the WW/SH3 domain of YAP1 mediates the interaction with NPM1 in C4-2 cells. Genetic and pharmacological inhibition of NPM1 activity reduced prostate cancer cell growth in culture by modulating cell cycle progression. Furthermore, our computational and immunological analysis of prostate tumor tissues indicated that the upregulation of NPM1 might be associated with the clinical advancement of human prostate cancer. These findings underscore the critical role of the molecular functional connection between YAP1 and RBPs and the global changes in RBP and RNA interaction patterns, in the progression and recurrence of prostate cancer. Citation Format: Abdulrahman M. Dwead, Marwah M. Al-Mathkour, Bekir Cinar. Androgen hormone signaling regulates the association between the hippo pathway component YAP1 and RNA binding protein NPM1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4386.

Abstract 7524: Targeting siglec-7/9 glyco-immune checkpoints in prostate cancer for enhanced immune responses and tumor suppression

Abstract Prostate cancer is one of the leading causes of death in men worldwide. Despite significant advancements in the fight against cancer, immune checkpoint inhibitors have limited effectiveness in treating prostate cancer. Evidence shows that disrupting the interactions between Siglec-7/9 and sialic acids can enhance immune responses and effectively inhibit tumor growth in several cancers. However, the understanding of Siglec-7/9-sialic acid interactions in prostate cancer remains limited. Here, we found that tumor-infiltrating immune cells derived from prostate cancer patients exhibited high levels of Siglec-7 and Siglec-9. TCGA data analysis suggests that high levels of Siglec-7/9 are correlated to worse patient survival. Elevated levels of Siglec-7/9 ligands were found in prostate tumor tissues compared to adjacent normal tissues. Prostate cancer cell lines exhibited significant expression levels of Siglec-7 and Siglec-9 ligands, and cell surface sialic acids. Proteomic analysis suggests that increased sialylation was observed in tumor tissues in comparison to adjacent normal tissues. Disrupting interactions between Siglec-7/9 and sialoglycans enhanced T cell-mediated cytotoxicity against prostate cancer cells. Treatment with anti-Siglec-7/9 antibodies effectively suppressed the growth of PC3 and 22Rv1 tumors in a humanized mouse model. Immunohistochemistry analysis of tumor tissues showed that PC3 and 22Rv1 tumors treated with anti-Siglec-7/9 exhibited reduced proliferation, decreased vascularization, increased apoptosis, and enhanced immune cell infiltration. The CRISPR screen and mass spectrometry analysis suggested CD59 as a potential ligand for Siglec-9. Knockout of CD59 in prostate cancer cells decreased their binding activity of Siglec-9-Fc chimera proteins and promoted T cell-mediated killing ability. These findings provide valuable insights into the potential therapeutic strategy of targeting Siglec-7/9 and their ligands for prostate cancer treatment. Citation Format: Ru Wen, G Edward Marti, Jessica Stark, Fernando Jose Garcia Marques, Nick Riley, Abel Bermudez, Hongjuan Zhao, Carolyn Bertozzi, Sharon Pitteri, James Brooks. Targeting siglec-7/9 glyco-immune checkpoints in prostate cancer for enhanced immune responses and tumor suppression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7524.

ALAN is a computational approach that interprets genomic findings in the context of tumor ecosystems

Gene behavior is governed by activity of other genes in an ecosystem as well as context-specific cues including cell type, microenvironment, and prior exposure to therapy. Here, we developed the Algorithm for Linking Activity Networks (ALAN) to compare gene behavior purely based on patient -omic data. The types of gene behaviors identifiable by ALAN include co-regulators of a signaling pathway, protein-protein interactions, or any set of genes that function similarly. ALAN identified direct protein-protein interactions in prostate cancer (AR, HOXB13, and FOXA1). We found differential and complex ALAN networks associated with the proto-oncogene MYC as prostate tumors develop and become metastatic, between different cancer types, and within cancer subtypes. We discovered that resistant genes in prostate cancer shared an ALAN ecosystem and activated similar oncogenic signaling pathways. Altogether, ALAN represents an informatics approach for developing gene signatures, identifying gene targets, and interpreting mechanisms of progression or therapy resistance.

PD04-06 IDENTIFYING NOVEL REGULATORS OF MACROPHAGE TUMOR CELL METABOLIC INTERACTIONS IN PROSTATE CANCER

You have accessJournal of UrologyCME1 Apr 2023PD04-06 IDENTIFYING NOVEL REGULATORS OF MACROPHAGE TUMOR CELL METABOLIC INTERACTIONS IN PROSTATE CANCER Asmaa Elkenawi, Ryan Putney, Amparo Serna, Jasreman Dhillon, and Kosj Yamoah Asmaa ElkenawiAsmaa Elkenawi More articles by this author , Ryan PutneyRyan Putney More articles by this author , Amparo SernaAmparo Serna More articles by this author , Jasreman DhillonJasreman Dhillon More articles by this author , and Kosj YamoahKosj Yamoah More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003228.06AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: African American men (AA) are more than twice as likely to die of prostate cancer (PCa) compared to European American men (EA). Among many contributing factors, unraveling the metabolic derangements in PCa of AA holds a promise in reducing health disparity. METHODS: We examined publicly available prostate cancer datasets for race dependent differential gene expression. We prospectively examined the differential gene expression of PCa from clinically matched AA and EA in the VANDAAM clinical trial. The VANDAAM study is a validation study of DecipherTM genomic testing in 240 men with localized PCa. We combined computational and experimental approaches to explore the molecular mechanisms of top candidate genes including these involved in metabolism. We then developed a novel metabolomic workflow that profiles patient- specific nutrient consumption to predict anti-cancer efficacy and validate novel biomarkers. RESULTS: We identified aminopeptidase N (ANPEP) as one of the top candidate genes to be overexpressed in AA. Aminopeptidase N is involved in endocytosis, cholesterol and amino acid transport and peptide hydrolysis. Unbiased computational analyses of the VANDAAM revealed that ANPEP correlates with signatures of cholesterol transport, estrogen and androgen receptor (AR) signaling. Based on our recent study demonstrating dominance of these signatures in macrophage rich PCa, we reasoned that ANPEP expression may be driven in part by high macrophage infiltration in AA. Thus, we compared immune cell repertoire in patients with high ANPEP and low ANPEP by deconvoluting immune cell content using the in silico approach, CIBERSORT. These analyses illustrated that only AA patients with high ANPEP expression significantly accumulated high content of M1 inflammatory macrophages. Immune phenotyping of prostate tumors demonstrated that ANPEP indeed represents a marker of M1 inflammatory macrophages. To unravel role of ANPEP in regulating cholesterol and amino acid transport, we developed a Liquid chromatography-high resolution mass spectrometry (LC-HRMS) -based approach to measure cholesterol and amino acids in explants derived from AA and EA prostate cancer patients. This innovative approach enables us to perform mechanistic studies by determining metabolic dependency on specific amino acids as a function ANPEP or macrophage infiltration. CONCLUSIONS: ANPEP represents a macrophage related protein in PCa with a potential role in cholesterol, amino acid transport and / or androgen signaling. Source of Funding: Prostate Cancer Foundation (AE), Urology Care Foundation (AE), Prostate Cancer Foundation (KY) and Department of Defense award CDMRP-PC181013 (KY) © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e144 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Asmaa Elkenawi More articles by this author Ryan Putney More articles by this author Amparo Serna More articles by this author Jasreman Dhillon More articles by this author Kosj Yamoah More articles by this author Expand All Advertisement PDF downloadLoading ...

RF05 | PSUN358 ANPEP: A potential regulator of tumor cell - macrophage metabolic interactions in prostate cancer of African American men

Abstract African American men (AA) are more than twice as likely to die of prostate cancer (PCa) compared to European American men (EA). Among many contributing factors, unraveling the metabolic derangements in PCa of AA holds a promise in reducing health disparity. We recently discovered that aminopeptidase N (ANPEP, CD13) represents one of the differentially expressed genes in PCa of AA compared with EA. While ANPEP plays regulatory and/or modulatory functions in many immune and metabolic pathological conditions, its role in PCa remains unknown. We sought to investigate the metabolic functions of ANPEP in PCa development and exploit its role as a therapeutic vulnerability, particularly in AA men. Accordingly, we prospectively examined the differential gene expression of PCa from clinically matched AA and EA in the VANDAAM clinical trial. The VANDAAM study is a validation study of DecipherTM genomic testing in 240 men with localized PCa. Our findings indicate that ANPEP is the top differentially expressed gene between AA and EA men. To explore the molecular mechanisms of ANPEP in PCa in unbiased fashion, we combined computational and experimental approaches. Our preliminary computational analyses revealed that ANPEP correlates with signatures of cholesterol transport, estrogen and androgen receptor (AR) signaling. Based on our recent study demonstrating dominance of these signatures in macrophage-rich PCa, we reasoned that ANPEP expression may be driven in part by high macrophage infiltration in AA. Thus, we compared immune cell repertoire in patients with high ANPEP and low ANPEP by deconvoluting immune cell content using the in silico approach, CIBERSORT. These analyses illustrated that only AA patients with high ANPEP expression significantly accumulated high content of M1 inflammatory macrophages. Immune phenotyping of prostate tumors demonstrated that ANPEP indeed represents a marker of M1 inflammatory macrophages and tumor-associated macrophages. In conclusion, these findings suggest that ANPEP is a macrophage related protein in PCa with a potential role in cholesterol transport and / or androgen signaling. Future work will focus on the functional role of ANPEP activity in the tumor immune microenvironment using Liquid chromatography-high resolution mass spectrometry (LC-HRMS) and explants derived from AA and EA prostate cancer patients. Presentation: Saturday, June 11, 2022 1:00 p.m. - 1:05 p.m., Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

Abstract 3816: Functional atlas of prostate mesenchyme

Abstract Prostate cancer has a heterogeneous prognosis, and genetic alterations alone do not fully explain clinical behavior. We previously characterized the stroma of localized human prostates by Laser Capture Microdissection, and found that stroma was substantially different in prostates with and without tumor. Furthermore, a stromal gene signature reflecting bone remodeling was upregulated in high compared to low Gleason grade cases. To determine how stromal cells contribute to carcinogenesis and progression we study whether specific genetic alterations in the epithelium induce unique stromal changes. To do this, we utilized Genetically Engineered Mouse Models (GEMMs) representing common prostate cancer mutations and compared these to their wild-type conterparts: the Tmprss2-ERG fusion knock-in murine model induces histological alterations in the stroma in the absence of an epithelial phenotype; the Pten deletion mouse model (PtenKO) results in prostate intraepithelial neoplasia (PIN) but not invasive cancer; the Hi-Myc GEMM, leads to PIN and subsequently invasion; and the Pb4-Cre +/-;Pten f/f; LSL-MYCN +/+; Rb1 f/f (MNRPDKO) mouse model that leads to neuroendocrine prostate cancer (NEPC). We generated a comprehensive single-cell transcriptomic atlas of the mouse prostate cancer mesenchyme in these models. Using deep generative modeling followed by graph-based clustering and gene regulatory network inference, six (6) distinct subsets of fibroblasts and two (2) subsets of smooth muscle cells (myofibroblasts and pericytes) were identified. Notably, some subsets were common across all GEMMs and WT mice, while others aligned with specific genotypes. Moreover, we found a variable pattern of positive and negative Ar expressing cells between genotypes. Analysis by CellphoneDB of mesenchymal-epithelial communications revealed the complex cross-talk between mutated epithelial cells and the tumor microenvironment. Multiplex immunofluorescence phenotyping of mesenchymal cell confirmed the cluster subtypes by both expression and spatial location. Finally, stromal transcripts defining mesenchymal cluster subtypes associated with Tmprss2-ERG were conserved between mouse and human genotypes.This study lays the groundwork for understanding and ultimately targeting stromal-epithelial interactions in prostate cancer. Citation Format: Hubert Pakula, Ryan Carelli, Nicolo Fanelli, Madhavi Jere, Caitlin Unkenholz, Mohamed Omar, Caroline Ribeiro- Fidalgo, Filippo Pederzoli, Cory Abate-Shen, David S. Rickman, Brian Robinson, Luigi Marchionni, Massimo Loda. Functional atlas of prostate mesenchyme [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3816.

ANPEP: A Potential Regulator of Tumor Cell—Immune Metabolic Interactions in Prostate Cancer of Men of African Descent

PURPOSE Prostate cancer (PCa) is the leading cause of male cancer deaths in Africa. In USA, African American men (AA) experience higher mortality rate compared to European American men (EA). While socioeconomics factors contribute toward these disparities, distinct molecular mechanisms in AA remain important drivers. For example, in previous work, we discovered that PCa form AA men harbored a significantly higher expression of Aminopeptidase N (ANPEP) as compared with EA. Aminopeptidase N regulates immune cell function and mediates tumor cell migration but its role in PCa remains uninvestigated. METHODS We explored ANPEP expression related to a range of genomic classifiers in multiple datasets. We then prospectively examined the differentially expressed genes in PCa tissues collected from 120 AA and 120 EA patients enrolled on the VANDAAM clinical trial. We further correlated ANPEP expression with various signatures related to immune and metabolic activity. We also experimentally examined the expression of ANPEP in different components of tumor microenvironment. RESULTS In the VANDAAM study, ANPEP represents the top differentially expressed gene between AA and EA men. Our data driven approach revealed that ANPEP correlates with signature of cholesterol transport and androgen signaling. Interestingly, these signatures dominate in PCa with high macrophage infiltration. Deconvolution of immune cell content using computational approaches indeed demonstrated that only AA patients with high ANPEP expression significantly accumulated high content of inflammatory macrophages. Further experimental findings showed that ANPEP indeed represents a marker of tumor-associated macrophages, a type of immune cells known to contribute to PCa progression. CONCLUSION We have identified ANPEP as a macrophage-related gene with a potential role in cholesterol metabolism and AR signaling in AA. Future work will focus on the functional role of ANPEP activity in the tumor immune microenvironment using Liquid chromatography-high resolution mass spectrometry and explants derived from AA and EA PCa patients.

Primary Tumor Resection Decelerates Disease Progression in an Orthotopic Mouse Model of Metastatic Prostate Cancer

Simple SummaryIn this preclinical in-vivo study, we used an orthotopic prostate cancer mouse model to analyze the effects of primary tumor resection on further disease progression and survival in metastatic prostate cancer. Sixty-four mice with metastatic prostate cancer, induced by intraprostatic injection of three-dimensional prostate cancer spheroids, were randomized into two groups: one group received resection of their primary tumor while the other group received a sham operation. After this, the mice were followed-up for 10 weeks. In comparison with the sham operation group, mice with primary tumor resection showed significantly slower PSA progression, less lung metastases, and significantly longer survival. These results are a hint towards a beneficial oncological effect of primary tumor resection in metastatic prostate cancer. Furthermore, the established versatile in-vivo model can be used to study the molecular mechanisms of primary tumor/metastasis interaction in prostate cancer.Radical prostatectomy in oligometastatic prostate cancer is a matter of intense debate. Besides avoiding local complications, it is hypothesized that primary tumor resection may result in better oncological outcomes. The aim of our study was to analyze the effect of primary tumor resection on disease progression in an orthotopic prostate cancer mouse model. First, the optimal time point for primary tumor resection, when metastases have already occurred, but the primary tumor is still resectable, was determined as 8 weeks after inoculation of 5 × 105 LuCaP136 cells. In a second in vivo experiment, 64 mice with metastatic prostate cancer were randomized into two groups, primary tumor resection or sham operation, and disease progression was followed up for 10 weeks. The technique of orthotopic primary tumor resection was successfully established. Compared with the sham operation group, mice with primary tumor resection showed a significantly longer survival (p < 0.001), a significantly slower PSA increase (p < 0.01), and a lower number of lung metastases (p = 0.073). In conclusion, primary tumor resection resulted in slower disease progression and longer survival in an orthotopic mouse model of metastatic prostate cancer. In future studies, this model will be used to unravel the molecular mechanisms of primary tumor/metastasis interaction in prostate cancer.

Increased Hospitalization and Mortality from COVID-19 in Prostate Cancer Patients.

Simple SummaryThe COVID-19 pandemic has had a remarkable and insurmountable effect on humankind. The SARS-Co-V2 infection results in a life-threatening situation, particularly in people at risk of severe infection, including those of old age, with comorbidities, and of the male gender. Prostate cancer (PCa), the most common cancer in men, shares several risk factors with COVID-19. Our study’s aim in 286,609 patients was to assess if men with prostate cancer and SARS-Co-V2 infection have poor clinical outcomes compared with patients with non-prostate GU malignancies. We confirmed that prostate cancer patients with COVID-19 had higher hospitalization and mortality rates. Among the comorbidities reported, prostate cancer patients with diabetes had a higher likelihood of being hospitalized, while COVID-19-positive prostate cancer patients with COPD had higher mortality rates. In summary, the work presented here advocates for better management of COVID-19 in prostate cancer patients, including vaccine prioritization.Background: Cancer patients with COVID-19 have a poor disease course. Among tumor types, prostate cancer and COVID-19 share several risk factors, and the interaction of prostate cancer and COVID-19 is purported to have an adverse outcome. Methods: This was a single-institution retrospective study on 286,609 patients who underwent the COVID-19 test at Mount Sinai Hospital system from March 2020 to December 2020. Chi-square/Fisher’s exact tests were used to summarize baseline characteristics of categorical data, and Mann–Whitney U test was used for continuous variables. Univariable logistic regression analysis to compare the hospitalization and mortality rates and the strength of association was obtained by the odds ratio and confidence interval. Results: This study aimed to compare hospitalization and mortality rates between men with COVID-19 and prostate cancer and those who were COVID-19-positive with non-prostate genitourinary malignancy or any solid cancer, and with breast cancer patients. We also compared our studies to others that reported the incidence and severity of COVID-19 in prostate cancer patients. Our studies highlight that patients with prostate cancer had higher susceptibility to COVID-19-related pathogenesis, resulting in higher mortality and hospitalization rates. Hospitalization and mortality rates were higher in prostate cancer patients with COVID-19 when compared with COVID-19 patients with non-prostate genitourinary (GU) malignancies.

Integrated Characterization of lncRNA-Immune Interactions in Prostate Cancer.

Prostate cancer is among the top mortality factors in male around the world. Long non-coding RNAs (lncRNAs) have been shown to play crucial roles in tumor biology and immunology. However, lncRNA-immune interactions have not yet examined in prostate cancer. Here, we performed integrated analysis to characterize lncRNA-immune interactions in prostate cancer through multidimensional aspects, including immune-related hallmarks, tumor immunogenomic signatures, immune-related biological processes, immune cells, and immune checkpoints. We dissected the dysregulation of lncRNAs and their clinical relevance in prostate cancer, such as RP11-627G23.1 and RP11-465N4.5. Immune-related hallmarks took up the major parts among top significant lncRNA-hallmark interactions. Our analysis revealed that TGF-β signaling pathway was the most frequent to associate with lncRNAs, which is a signature of immune response in cancer. In addition, immune response and its regulation were the most closely connected immunological processes with lncRNA, implying the regulatory roles of lncRNAs on immune response in prostate cancer. We found that memory resting CD4+ T cells were the most lncRNA-correlated immune cell. LINC00861 was found to be potentially intervening targets of immunotherapy for prostate cancer patients, which was significantly associated with PD-1 and CTLA4. Collectively, we offered a handy resource to investigate regulatory roles of lncRNAs on tumor immunology and the development of clinical utility of lncRNAs in prostate cancer.

The landscape of RNA polymerase II-associated chromatin interactions in prostate cancer.

Transcriptional dysregulation is a hallmark of prostate cancer (PCa). We mapped the RNA polymerase II-associated (RNA Pol II-associated) chromatin interactions in normal prostate cells and PCa cells. We discovered thousands of enhancer-promoter, enhancer-enhancer, as well as promoter-promoter chromatin interactions. These transcriptional hubs operate within the framework set by structural proteins - CTCF and cohesins - and are regulated by the cooperative action of master transcription factors, such as the androgen receptor (AR) and FOXA1. By combining analyses from metastatic castration-resistant PCa (mCRPC) specimens, we show that AR locus amplification contributes to the transcriptional upregulation of the AR gene by increasing the total number of chromatin interaction modules comprising the AR gene and its distal enhancer. We deconvoluted the transcription control modules of several PCa genes, notably the biomarker KLK3, lineage-restricted genes (KRT8, KRT18, HOXB13, FOXA1, ZBTB16), the drug target EZH2, and the oncogene MYC. By integrating clinical PCa data, we defined a germline-somatic interplay between the PCa risk allele rs684232 and the somatically acquired TMPRSS2-ERG gene fusion in the transcriptional regulation of multiple target genes - VPS53, FAM57A, and GEMIN4. Our studies implicate changes in genome organization as a critical determinant of aberrant transcriptional regulation in PCa.

Integrative Analysis of MicroRNA and Gene Interactions for Revealing Candidate Signatures in Prostate Cancer.

MicroRNA (miRNA)–gene interactions are well-recognized as involved in the progression of almost all cancer types including prostate cancer, which is one of the most common cancers in men. This study explored the significantly dysregulated genes and miRNAs and elucidated the potential miRNA–gene regulatory network in prostate cancer. Integrative analysis of prostate cancer and normal prostate transcriptomic data in The Cancer Genome Atlas dataset was conducted using both differential expression analysis and weighted correlation network analysis (WGCNA). Thirteen genes (RRM2, ORC6, CDC45, CDKN2A, E2F2, MYBL2, CCNB2, PLK1, FOXM1, CDC25C, PKMYT1, GTSE1, and CDC20) were potentially correlated with prostate cancer based on functional enrichment analyses. MiRNAs targeting these genes were predicted and eight miRNAs were intersections between those miRNAs and the hub miRNAs obtained from miRNA WGCNA analysis. Three genes (E2F2, RRM2, and PKMYT1) and four miRNAs (hsa-mir-17-5p, hsa-mir-20a-5p, hsa-mir-92a-3p, and hsa-mir-93-5p) were key factors according to the interaction network. RRM2 and PKMYT1 were significantly related to survival. These findings partially elucidated the dysregulation of gene expressions in prostate cancer. Efficient manipulations of the miRNA–gene interactions in prostate cancer may be exploited as promising therapeutics.

Stromal-epithelial interactions in prostate cancer: Overexpression of PAGE4 in stromal cells inhibits the invasive ability of epithelial cells.

It is now widely recognized that carcinoma-associated fibroblasts which are believed to be myofibroblasts, promote the transformation of prostate epithelial cells to cancer cells, enhance their proliferation and invasiveness, and induce the acquisition of resistance to cancer therapy and immune evasiveness. Prostate-associated gene 4 (PAGE4) is an intrinsically disordered protein that is remarkably prostate-specific. PAGE4 is also a stress-response protein that functions as a transcriptional regulator and is upregulated in early-stage prostate cancer (PCa) and its precursor lesions. However, PAGE4 is downregulated in high-grade PCa and metastatic disease. Here, we show that PAGE4 is highly expressed in the stromal cells surrounding the cancer-adjacent "normal" glands and low-grade PCa lesions but not in lesions proximal to high-grade PCa. Overexpression of PAGE4 in a stromal cell line inhibits the migration and invasion of PCa epithelial cells in multiple coculture systems. PAGE4 overexpression also inhibits the downregulation of E-cadherin in PCa epithelial cells when cocultured with stromal cells. Furthermore, signaling via tumor necrosis factor-α and transforming growth factor-β pathways is decreased in the stromal cells overexpressing PAGE4 suggesting that PAGE4 appears to play a protective role against disease progression by perturbing interactions between epithelial cells and stromal cells in PCa. Taken together, these findings support previous observations that upregulation of PAGE4 in PCa correlates with a better prognosis and highlight PAGE4 as a novel therapeutic target for early-stage "low-risk" disease.

LncRNA UCA1 Functions as a ceRNA to Promote Prostate Cancer Progression via Sponging miR143

UCA1 (urothelial carcinoma associated 1) is a long non-coding RNA (lncRNA) that was found overexpressed in various human cancers including prostate cancer (PCa). However, the aspect of UCA1-miRNA-mRNA interaction in PCa remains unclear. In this study, we confirmed the role of UCA1 in PCa and found that UCA1 downregulation inhibited cell proliferation of PCa cells. Then we demonstrated that repressed UCA1 promoted the microRNA-143 (miR-143) expression and miR-143 could bind to the predicted binding site of UCA1. We then proved the anti-tumor role of miR-143 in PCa. Furthermore, we found that miR-143 displays its role in PCa via modulating the MYO6 expression. In summary, our study demonstrated that UCA1 exerts oncogenes activity in PCa, acting mechanistically by upregulating MYO6 expression through “sponging” miR-143.

HOXB13 interaction with MEIS1 modifies proliferation and gene expression in prostate cancer.

The recurrent p.Gly84Glu germline mutation (G84E) in HOXB13 is consistently associated with prostate cancer (PCa), although the mechanisms underlying such linkage remain elusive. The majority of the PCa-associated HOXB13 mutations identified are localized to two conserved domains in HOXB13 that have been shown to mediate the interaction with MEIS cofactors belonging to the TALE family of homeodomain transcription factors. In this study, we sought to interrogate the biochemical and functional interactions between HOXB13 and MEIS in prostatic cells with a goal of defining how the HOXB13-MEIS complex impacts PCa pathobiology and define the extent to which the oncogenic activity of G84E is related to its effect on HOXB13-MEIS interaction/function. HOXB13 and MEIS paralog expression in prostate epithelial cells and PCa cell lines was characterized by qPCR and immunoblot analyses. HOXB13 and MEIS1 co-expression in human prostate tissue was confirmed by IHC, followed by co-IP mapping of HOXB13-MEIS1 interactions. Proliferation of the PCa cell line LAPC4 following shRNA-mediated knockdown of each gene or both genes was assessed using DNA- and metabolic-based assays. Transcriptional targets of HOXB13 and MEIS1 were identified by gene expression profiling and qPCR. Finally, protein stability of HOXB13 in the context of MEIS1 was determined using pulse-chase assays. HOXB13 and MEIS1 are co-expressed and interact in prostate cells. Both of the putative MEIS interacting domains (MID) within HOXB13 were shown to be capable of mediating the interaction between HOXB13 and MEIS1 independently and such interactions were not influenced by the G84E mutation. The inhibitory effect of either HOXB13 or MEIS1 knockdown on cellular proliferation was augmented by knockdown of both genes, and MEIS1 knockdown abolished HOXB13-driven regulation of BCHE and TNFSF10 mRNA expression. Notably, we demonstrated that MEIS1 stabilized the HOXB13 protein in LAPC4 cells. Our study provides evidence for functional HOXB13-MEIS1 interactions in PCa. MEIS1 may contribute to the cancer-promoting actions of HOXB13 in cellular proliferation and gene regulation by prolonging HOXB13 half-life. Our data demonstrates that G84E is not a loss-of-function mutation that interferes with HOXB13 stability or ability to interact with MEIS1.

Design of Peptoid-peptide Macrocycles to Inhibit the \u03b2-catenin TCF Interaction in Prostate Cancer

New chemical inhibitors of protein–protein interactions are needed to propel advances in molecular pharmacology. Peptoids are peptidomimetic oligomers with the capability to inhibit protein-protein interactions by mimicking protein secondary structure motifs. Here we report the in silico design of a macrocycle primarily composed of peptoid subunits that targets the β-catenin:TCF interaction. The β-catenin:TCF interaction plays a critical role in the Wnt signaling pathway which is over-activated in multiple cancers, including prostate cancer. Using the Rosetta suite of protein design algorithms, we evaluate how different macrocycle structures can bind a pocket on β-catenin that associates with TCF. The in silico designed macrocycles are screened in vitro using luciferase reporters to identify promising compounds. The most active macrocycle inhibits both Wnt and AR-signaling in prostate cancer cell lines, and markedly diminishes their proliferation. In vivo potential is demonstrated through a zebrafish model, in which Wnt signaling is potently inhibited.

Abstract LB-267: A small molecule mimic approach to the PEDF/LAMR1 interaction in prostate cancer

Abstract Pigment epithelium derived factor, or PEDF, is a well-known and potent inhibitor of angiogenesis. Our lab as well as others have examined PEDF as a novel prostate cancer therapy, as PEDF inhibits tumor establishment, promotes tumor cell differentiation, and induces tumor apoptosis. PEDF has been identified as a binding partner for the cancer associated protein Laminin Receptor (LAMR1). LAMR1 has been shown to be overexpressed in several types of cancers including breast, colon, and prostate. It has been reported in the literature that the PEDF/LAMR1 interaction inhibits tumor migration and invasion. Recent work in the lab investigated whether we could mimic the PEDF/LAMR1 interaction using a small molecule approach. Utilizing a 14,400 compound in-silico screen, we identified several small molecules as potential binders to the PEDF interaction interface of LAMR1. From those, we identified a hit compound with anti-proliferative capacity against several prostate cancer cell lines. In PC-3 cells, our hit compound showed activation of anti-tumor signaling and altered proteins associated with prostate cancer and DNA maintenance through LAMR1. We recently tested our hit compound as well as several structural analogs in PC-3 cells at 10 and 50 uM in a cell viability assay to compare the activity of the analogs with that of our hit compound. Several analogs showed activity comparable or superior to our hit compound at 50 uM, with at least a 95% reduction in cell viability after 48 and 96 hours. We are currently working to identify medium-throughput in vitro functional assays that can be utilized for compound screening and profiling. Through an iterative screening, characterization, and optimization process, we hope to identify a lead-type compound to use in future preclinical studies. We are also investigating the mechanism of action downstream of the PEDF/LAMR1 interaction in prostate cancer, which will help us shed light on the therapeutic potential of LAMR1. Support or Funding InformationCTSI Core Grant Purdue Cancer Research Center Department of Basic Medical Sciences Citation Format: Daniel F. Edwards, Charles S. Umbaugh, Marxa L. Figueiredo. A small molecule mimic approach to the PEDF/LAMR1 interaction in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-267.

The potential role of transforming growth factor beta family ligand interactions in prostate cancer

The transforming growth factor beta (TGF-β) family plays an important role in embryonic development and control of the cell cycle. Members of the TGF-β family have pleiotropic functions and are involved in both the inhibition and progression of various cancers. In particular, deregulation of the TGF-β family has been associated with prostate cancer, as both a mechanism of disease progression and a possible therapeutic target. This review concentrates on the TGF-βs, activins and inhibins, bone morphogenetic proteins and NODAL and their connection to prostate cancer. Whilst most studies examine the family members in isolation, there are multiple interactions that may occur between members which can alter their function. Such interactions include ligand competition for receptor binding and shared intracellular pathways such as the Mothers against decapentaplegic (SMAD) proteins. Another mechanism for interaction within the TGF-β family is facilitated by their dimeric structure; heterodimers can form which exhibit different functional capabilities to their homodimeric counterparts. The potential formation of TGF-β family heterodimers has not been well examined in prostate cancer. The multiple methods of interrelations between members highlights the need for gross analysis of the TGF-β family and related factors in association with prostate cancer, in order to discover possible future avenues for TGF-β based diagnosis and treatments of the disease. This review describes the role of the TGF-β family of proteins in cancer and, in particular, prostate cancer. After a brief overview, the role of individual members of the family is considered and how these members may be involved in prostate cancer growth is discussed. The review highlights the complex interactions that occur between family members and that may contribute to the progression of prostate cancer.

PO-0982: Therapeutic potential of the YB-1/Notch-3 interaction in prostate cancer

PO-0982: Therapeutic potential of the YB-1/Notch-3 interaction in prostate cancer