Androgen Receptor In Prostate Cancer Research Articles

Astragalus membranaceus Extract Induces Apoptosis via Generation of Reactive Oxygen Species and Inhibition of Heat Shock Protein 27 and Androgen Receptor in Prostate Cancers.

Although Astragalus membranaceus is known to have anti-inflammatory, anti-obesity, and anti-oxidant properties, the underlying apoptotic mechanism of Astragalus membranaceus extract has never been elucidated in prostate cancer. In this paper, the apoptotic mechanism of a water extract from the dried root of Astragalus membranaceus (WAM) was investigated in prostate cancer cells in association with heat shock protein 27 (HSP27)/androgen receptor (AR) signaling. WAM increased cytotoxicity and the sub-G1 population, cleaved poly (ADP-ribose) polymerase (PARP) and cysteine aspartyl-specific protease 3 (caspase 3), and attenuated the expression of B-cell lymphoma 2 (Bcl-2) in LNCaP cells after 24 h of exposure. Consistently, WAM significantly increased the number of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive LNCaP cells. WAM decreased the phosphorylation of HSP27 on Ser82 and inhibited the expression of the AR and prostate-specific antigen (PSA), along with reducing the nuclear translocation of p-HSP27 and the AR via the disturbed binding of p-HSP27 with the AR in LNCaP cells. WAM consistently inhibited the expression of the AR and PSA in dihydrotestosterone (DHT)-treated LNCaP cells. WAM also suppressed AR stability, both in the presence and absence of cycloheximide, in LNCaP cells. Taken together, these findings provide evidence that WAM induces apoptosis via the inhibition of HSP27/AR signaling in prostate cancer cells and is a potent anticancer candidate for prostate cancer treatment.

Unveiling the latest insights into Androgen Receptors in Prostate Cancer

Unveiling the latest insights into Androgen Receptors in Prostate Cancer

Identification of apposite antagonist for androgen receptor in prostate cancer: an in silico study of fenugreek compounds

Benign Prostate Cancer (BPC), a prevalent condition predominantly affecting elderly males, manifests with voiding difficulties and urinary retention. A library of compounds from Trigonella foenum-graecum, commonly known as fenugreek was used in this study. We aimed to explore its potential anti-cancer effects by computationally assessing its inhibitory activity on the androgen receptor (AR). For in-silico drug assessment, we employed Maestro 12.8, part of the Schrödinger Suite, to identify the most promising candidates acting as androgen receptor antagonists in the treatment of BPC. Subsequently, 59 fenugreek compounds were retrieved from the PubChem database and subjected to molecular docking against the active site of the target protein, 1E3G. 100-nanosecond molecular dynamics (MD) simulations were performed to assess the stability and compactness of the AR-ligand complexes. Notably, the AR-kaempferol complex exhibited the least fluctuation within the AR active site throughout the simulation trajectory, followed by chlorogenic acid and the reference ligand, hydroxyflutamide. The MM/GBSA values revealed the compounds’ maximum free binding energy (−103.3 ± 6, −87.4 ± 23, −68.5 ΔGbind) for chlorogenic acid, kaempferol, and hydroxyflutamide, respectively. These findings suggest their potential as promising leads for drug development. Further lead optimization and comprehensive studies on the top-ranked ligands identified in this investigation are warranted to advance their potential as therapeutic agents for BPC treatment. Communicated by Ramaswamy H. Sarma

THU496 A Positive Relationship Exists Between CARF And AR In Prostate Cancer

Abstract Disclosure: K.M. Hasan: None. H. Khambati: None. R.R. Huerta: None. J. Vadgama: None. A.P. Sinha-Hikim: None. T.C. Friedman: None. Prostate cancer (PCa) is the second most prevalent cancer among men worldwide. Since PCa onset is androgen dependent, androgen deprivation therapy (ADT) is the first treatment choice for a primary tumor or metastatic PCa. However, ADT eventually leads to the development of castration resistant PCa (CRPC), which is the leading cause of higher mortality in PCa. Thus, there is a need to identify the underlying mechanisms of CRPC to manage this aggressive disease. Increased androgen receptor (AR) expression is one of the most important factors contributing to the development of CRPC. It has been shown that tumor suppressor p53 negatively regulates the expression of AR. So, loss of p53 functions has been associated with increased expression of AR in advanced PCa. However, the mechanism of p53-mediated inhibition of AR is not well understood. In this study, we demonstrated that CARF (CDKN2AIP), a p53 pathway regulatory protein, is highly expressed in PCa, but its significance in PCa development is unknown. Since, like AR, CARF is negatively regulated by p53, we hypothesize that a reciprocal relationship between CARF and p53 could regulate AR expression in PCa cells. Indeed, we found that activation of p53 by DNA damage stress inhibited both CARF and AR in LnCap and 22RV1, AR-positive, and wtp53 cell lines. Our result indicated that CARF and AR were decreased dose-dependent manner, and presumably, that could trigger cell death. Consistent with this speculation, we found that silencing CARF by ShRNA in LnCap triggered apoptosis and inhibition of cell proliferation. With great interest, we further demonstrated that silencing of CARF downregulated the AR level in LnCap and 22RV1 cells suggesting that CARF regulates the expression of AR in PCa. RT-PCR results showed that AR transcripts remained unchanged in CARF-depleted LnCap cells. This result indicated that CARF could regulate the AR stability but not the transcription. Intriguingly, we found that the expression of NEDD4, one of the AR-targeting E3 ligases, was increased in CARF-depleted cells. Therefore, by enhancing the stability, CARF could positively regulate the expression of AR in PCa cells. Further studies are in progress to know more details about the CARF-mediated AR regulation and its impact on androgen-independent PCa development and progression. Presentation: Thursday, June 15, 2023

Pinostilbene inhibits full-length and splice variant of androgen receptor in prostate cancer

Prostate cancer is the most prevalent cancer in men worldwide and is promoted by the sex hormone androgen. Expression of androgen from the testis can be significantly reduced through castration. However, as most prostate cancer patients acquire castration resistance, additional therapeutic solutions are necessary. Although anti-androgens, such as enzalutamide, have been used to treat castration-resistant prostate cancer (CRPC), enzalutamide-resistant CRPC (Enz-resistant CRPC) has emerged. Therefore, development of novel treatments for Enz-resistant CRPC is urgent. In this study, we found a novel anti-androgen called pinostilbene through screening with a GAL4-transactivation assay. We confirmed that pinostilbene directly binds to androgen receptor (AR) and inhibits its activation and translocalization. Pinostilbene treatment also reduced the protein level and downstream gene expression of AR. Furthermore, pinostilbene reduced the protein level of AR variant 7 in the Enz-resistant prostate cancer cell line 22Rv1 and inhibited cell viability and proliferation. Our results suggest that pinostilbene has the potential to treat Enz-resistant CRPC.

Abstract A082: The epigenetic impact and therapeutic opportunity of AR-directed therapy for desmoplastic small round cell tumor

Abstract Desmoplastic small round cell tumor (DSRCT) is a rare, usually incurable, aggressive sarcoma subtype that occurs predominantly in adolescent and young adult (AYA) males. At diagnosis, most present with hundreds of intraabdominal nodules composed of malignant cells that harbor a EWSR1-WT1 chromosomal translocation and resultant fusion protein (FP). It was shown that a subset of DSRCT cells (mostly of epithelial histotype) highly express the androgen receptor (AR), a key epigenetic driver of prostate cancer (PC). Given the male predilection and the high expression of AR, we sought to assess the role of AR more comprehensively in DSRCT and ask if this tumor shared AR resistance mechanism to PC. We tested if AR antagonists curb cell proliferation and tumor growth, where both enzalutamide and AR-antisense therapy blocked DHT-induced cell proliferation and reduced xenograft tumor burden. Next, to mechanistically interrogate AR’s oncogenic effects, we performed single-nuclei RNA-seq (snRNA-eq) and chromatin immunoprecipitation sequencing (ChIP-seq) on frozen patient specimens. Those studies revealed a surprising epigenetic similarity between DSRCT to PC. Though overlap exists in the DNA binding MOTIFs of AR in DSRCT and PC, our ChIP-seq resultsrevealed DSRCT-specific AR DNA binding sites adjacent to key oncogenic regulators, including FOXF1 and WT1 (the C-terminal partner of the pathognomonic FP). To our surprise, we identified a subset of DSRCT samples that underwent partial neuroendocrine (NE) epigenetic reprogramming, akin to what occurs in ~1/3 of castrate-resistant PC (CRPC). Since androgen deprivation therapy (ADT) isn’t yet a standard treatment for DSRCT, it remains an enigma why DSRCT would undergo NE reprogramming or how this may affect ADT sensitivity. To address this, nine DSRCT patient samples were profiled using snRNA-seq. Sub-clustering revealed epithelial, mesenchymal, or NE signatures and marked inter-patient and intra-tumoral heterogeneity. Notably, five of nine patients exhibited NE markers (SYP, ENO2, CHGA, FOXA2, ASCL1, and SOX2), while three expressed epithelial markers (MUC1, MUC6, KRT18, KRT23, CDH1). One patient exhibited a hybrid AR indifferent phenotype. While strikingly different from PC morphologically and phenotypically, our data suggest that DSRCT is a second androgen-stimulated malignancy (third if we consider breast cancers that rely on shared nuclear receptor family signaling). Shared dependence upon AR for tumor growth and survival provides an exciting opportunity to prospectively study AR signaling in a different cancer type and younger DSRCT-stricken patient population. Ongoing work will determine if DSRCT undergoes dedifferentiation towards a more stem-like cell as an intermediary step before undergoing neural lineage commitment or transdifferentiation directly from an epithelial cell type towards a neuroendocrine cell fate. We are also exploring if the FP acts as a Pioneer factor to direct AR towards DSRCT-specific androgen response elements that explain this sarcoma subtype’s unique clinical presentation. Citation Format: Danh D. Truong, Salah-Eddine Lamhamedi-Cherradi, Mayinuer Maitituoheti, Hannah C. Beird, Chia-Chin Wu, Sandhya Krishnan, Davis Ingram, P. Andrew Futreal, Mark Titus, Alexander Lazar, Kunal Rai, A. Robert MacLeod, Najat C. Daw, Andrea Hayes, Joseph Ludwig. The epigenetic impact and therapeutic opportunity of AR-directed therapy for desmoplastic small round cell tumor [abstract]. In: Proceedings of the AACR Special Conference: Advances in Prostate Cancer Research; 2023 Mar 15-18; Denver, Colorado. Philadelphia (PA): AACR; Cancer Res 2023;83(11 Suppl):Abstract nr A082.

Therapeutic potential of the splicing factor SRSF6 as a novel regulator of the Androgen Receptor in prostate cancer

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Abstract 3780: Reciprocal regulation between DNA methyl transferase 3A and 3B and microRNAs 299-3p and -30e are the causal factors for down regulation of microRNAs targeting androgen receptors in prostate cancer

Abstract Promoter hypermethylation is one of the events that downregulate microRNAs (miRNA), resulting in differential expression of genes and progression of cancer. Previously we showed down-regulation of two miRNAs, miR-299-3p and -30e that target androgen receptor (AR) in advanced prostate cancer (PCa), and their function as tumor suppressors. In this study, we examined the contributing events for the loss of expression of these miRNAs and if the expression varies in PCa tissues and cells from racially disparate group of patients. To test whether promoter hypermethylation is one of the reasons, we examined the effect of treatment of DNA methyl transferase (DNMT) inhibitor 5-Aza-2’-deoxycytidine (Aza-C) on expression of these miRNAs in PCa cells. We noted that the expression of miRs-299-3p, -30e and -34c, another AR-targeting miRNA can be restored in PCa cells upon Aza-C treatment, which suggests that promoter hypermethylation is possibly responsible for down regulation of these miRNAs. We noted that miR- miR-299-3p, -34c and -30e are differentially expressed in PCa tissues and cells from African American (AA) and European American (CA) patients. Through bisulfite sequencing, we showed differential promoter methylation of mir-34c and -299-3p genes in PCa cell lines from AA and CA origins, which can be reversed through treatment with Aza-C. Differential expression and activities of DNMT3A and DNMT3B were also noted in PCa cells. Analysis of miRNA target prediction databases suggested that both miRs-299-3p and -30e have one or more binding sites at the 3’UTRs of DNMT3A and DNMT3B, which was confirmed by luciferase reporter assays. Interaction of these DNMTs with miR-299-3p was further established by Argonaut (Ago)-2-based RNAIP using induced C4-2B PCa cells overexpressing miR-299-3p. Interaction of miR-30e with these DNMTs was also confirmed by transfection of biotinylated miRNA mimic and streptavidin-based RNA pulldown assays. Overexpression of miRs-299-3p and -30e in PCa cells downregulated expression of mRNAs and proteins, and the activity of DNMTs. Ectopic expression of miR-299-3p restored expression of miR-34c and -30e in PCa cells. Similarly, overexpression of miR-30e restored expression of miR-34c and -299-3p. These observations confirmed that the increased expression of miRs-30e or -299-3p overcomes the loss of expression of miRNAs including miRs-299-3p and -34c, which is potentially mediated by DNMT induced promoter hypermethylation. This study established a reciprocal regulatory loop of AR targeting miRNAs and DNMTs in PCa cells and provides a mechanistic insight into the aberrant expression of AR in advanced PCa as a result of down regulation of miRs-299-3p, -34c and -30e and stabilization of expression and activities of DNMTs. Citation Format: Kavya Ganapathy, Christian Harrs, Samuel Harris, Ayman Khatib, Jong Park, Ratna Chakrabarti. Reciprocal regulation between DNA methyl transferase 3A and 3B and microRNAs 299-3p and -30e are the causal factors for down regulation of microRNAs targeting androgen receptors in prostate cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3780.

Abstract 1454: SMAD3 promotes expression and activity of the androgen receptor in prostate cancer

Abstract Overexpression of the androgen receptor (AR) is the primary cause of development of castration-resistant prostate cancer (CRPC), although mechanisms upregulating AR transcription in this context are not well understood. Our RNA-seq analysis revealed AR as the top pathway altered after SMAD3 knockdown in prostate cancer cells. SMAD3 knockdown decreased levels of AR, AR-V7 and AR target gene transcripts, whereas SMAD4 or SMAD2 knockdown had little or no effect. ChIP-seq analysis showed that SMAD3 knockdown decreased global binding of AR to chromatin. Mechanistically, we show that SMAD3 binds to intron 3 of the AR gene to promote AR expression. Targeting these binding sites by CRISPRi reduced transcript levels of AR and AR targets. In addition, ~50% of AR or SMAD3 ChIP-seq peaks overlapped, and SMAD3 may also cooperate with or co-activate AR in terms of AR target expression. Functionally, AR re-expression in SMAD3-knockdown cells partially rescued AR target expression and cell growth defects. AR and SMAD3 mRNAs were upregulated in datasets of metastatic prostate cancer and CRPC compared with primary prostate cancer. This study suggests that SMAD3 could be targeted to downregulate AR expression and activity and as potential anti-prostate cancer therapy. Citation Format: Hee-Young Jeon, Majid Pornour, Hyunju Ryu, Sudeep Khadka, Rui Xu, Jihyun Jang, Deqiang Li, Hegang Chen, Arif Hussain, Ladan Fazli, Martin Gleave, Xuesen Dong, Qianben Wang, Christopher Barbieri, Jianfei Qi. SMAD3 promotes expression and activity of the androgen receptor in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1454.

Abstract 1996: Prostate cancer androgen receptor signaling inhibition via romidepsin encapsulated lipid-polymer hybrid nanoparticle with PSMA617 targeting

Abstract Purpose/Objective(s): Androgen deprivation therapy (ADT) has been a clinical standard of care for the treatment of castration sensitive prostate cancer (CSPC). However, it is not curative, and ADT has significant systemic effects including hot flashes, osteoporosis, anemia, etc. We sought to identify agents that would inhibit AR signaling without causing these systemic effects. Histone deacetylase inhibitors (HDACis) are attractive agents because they impede AR signaling and DNA damage repair in PCa and show epigenetic modifications in prostate cancer (PCa) development and progression. This study demonstrated romidepsin as an alternative to ADT and the development of a romidepsin encapsulated CSPC PCa targeted nanoparticle for PCa cell killing and growth inhibition without the toxicity associated with free romidepsin or ADT. Materials/Methods: Three PCa cell lines, LNCaP, 22Rv1 and PC3 that express different androgen receptor (AR) levels were used for this study. Cell viability was tested by real-time cell analysis (RTCA), protein expression by western blot analysis, and quantification of γ-H2AX double stranded DNA (dsDNA) breaks by immunofluorescent microscopy. We developed a poly (D,L-lactide-co-glycolide) (PLGA) and 1, 2-Distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol (DSPE-PEG) polymer-lipid nanoparticle coated with vipivotide tetraxetan(PSMA-617) for prostate specific membrane antigen (PSMA) targeting. Nanoparticles were characterized by transmission electron microscope (TEM), dynamic light scattering (DLS) analysis, and nanoparticle tracking analysis (NTA). Romidepsin encapsulation efficiency was quantified by high-performance liquid chromatography(HPLC). Results: RTCA showed free romidepsin inhibited cell growth in all three PCa cell lines in a dose dependent manner. The addition of ADT exhibited an additive effect with low romidepsin doses, but did not significantly improve cell growth inhibition when combined with high doses of romidepsin. Western blot and γ-H2AX foci staining confirmed that romidepsin inhibited AR signaling and increased dsDNA damage, respectively. HPLC showed nanoparticle encapsulated romidepsin of 0.7%wt and TEM/DLS/NTA showed a size of 130 ±20nm. Furthermore, PSMA-617 coated nanoparticles exhibited enhanced uptake in LNCaP cells compared to non-coated nanoparticles. Conclusion: Our study showed that the romidepsin has a dual effect on inhibiting AR signaling as well as downregulating DNA damage repair genes. Additionally, we developed a PCa targeted nanoparticle for specific PCa delivery of romidepsin. PSMA-targeted, romidepsin-encapsulated nanoparticles would reduce the systemic effects of free romidepsin and a potential replacement for ADT. Citation Format: Wendi Ma, Daiki Hara, Yu-Ping Yang, Olivia Yolande Bosquet, Wei Zhang, Emre Dikici, Huayang Feng, Tim Horton, Wensi Tao, Jessi Hersh, Junwei Shi, Sylvia Daunert, Sapna Deo, Alan Pollack. Prostate cancer androgen receptor signaling inhibition via romidepsin encapsulated lipid-polymer hybrid nanoparticle with PSMA617 targeting [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1996.

SMAD3 promotes expression and activity of the androgen receptor in prostate cancer.

Overexpression of androgen receptor (AR) is the primary cause of castration-resistant prostate cancer, although mechanisms upregulating AR transcription in this context are not well understood. Our RNA-seq studies revealed that SMAD3 knockdown decreased levels of AR and AR target genes, whereas SMAD4 or SMAD2 knockdown had little or no effect. ChIP-seq analysis showed that SMAD3 knockdown decreased global binding of AR to chromatin. Mechanistically, we show that SMAD3 binds to intron 3 of the AR gene to promote AR expression. Targeting these binding sites by CRISPRi reduced transcript levels of AR and AR targets. In addition, ∼50% of AR and SMAD3 ChIP-seq peaks overlapped, and SMAD3 may also cooperate with or co-activate AR for AR target expression. Functionally, AR re-expression in SMAD3-knockdown cells partially rescued AR target expression and cell growth defects. The SMAD3 peak in AR intron 3 overlapped with H3K27ac ChIP-seq and ATAC-seq peaks in datasets of prostate cancer. AR and SMAD3 mRNAs were upregulated in datasets of metastatic prostate cancer and CRPC compared with primary prostate cancer. A SMAD3 PROTAC inhibitor reduced levels of AR, AR-V7 and AR targets in prostate cancer cells. This study suggests that SMAD3 could be targeted to inhibit AR in prostate cancer.

Potential Protective Effects of Testosterone Therapy on Prostate Cancer

This review article encompasses the historical perspective of androgen deprivation therapy by first reviewing the early research conducted by Huggins and Hodge, followed by a cellular biological discussion of androgen receptors in prostate cancer (PCa) physiology, leading to a subsequent discussion of the risk and potential therapeutic role of testosterone therapy in localized, oligometastatic, and metastatic PCa.

Downregulation of miR-99b-5p and Upregulation of Nuclear mTOR Cooperatively Promotes the Tumor Aggressiveness and Drug Resistance in African American Prostate Cancer.

Mammalian target of rapamycin (mTOR) regulates various fundamental cellular events including cell proliferation, protein synthesis, metabolism, apoptosis, and autophagy. Tumor suppressive miR-99b-5p has been implicated in regulating PI3K/AKT/mTOR signaling in a variety of types of cancer. Our previous study suggested the reciprocal miR-99b-5p/MTOR (downregulated/upregulated) pairing as a key microRNA-mRNA regulatory component involved in the prostate cancer (PCa) disparities. In this study, we further validated the expression profiles of mTOR and miR-99b-5p in the PCa, colon, breast, and lung cancer specimens and cell lines. The immunohistochemistry (IHC), immunofluorescence, Western blot, and RT-qPCR assays have confirmed that mTOR is upregulated while miR-99b-5p is downregulated in different patient cohorts and a panel of cancer cell lines. Intriguingly, elevated nuclear mTOR expression was observed in African American PCa and other advanced cancers. Transfection of the miR-99b-5p mimic resulted in a significant reduction in nuclear mTOR and androgen receptor (AR), while a slight/moderate to no decrease in cytoplasmic mTOR and AR in PCa and other cancer cells, suggesting that miR-99b-5p inhibits mTOR and AR expression and their nuclear translocation. Moreover, overexpression of miR-99b-5p targets/inhibits AR-mTOR axis, subsequently initiating cell apoptosis and sensitizing docetaxel-induced cytotoxicity in various cancers. In conclusion, our data suggest that reciprocal miR-99b-5p/nuclear mTOR pairing may be a more precise diagnostic/prognostic biomarker for aggressive PCa, than miR-99b-5p/MTOR pairing or mTOR alone. Targeting the AR-mTOR axis using miR-99b-5p has also been suggested as a novel therapeutic strategy to induce apoptosis and overcome chemoresistance in aggressive PCa.

The Prostate Cancer Androgen Receptor Cistrome in African American Men Associates with Upregulation of Lipid Metabolism and Immune Response.

With immunotherapies and inhibitors of metabolic enzymes in clinical development, the altered lipid metabolism and immune response in African-American men provides potential therapeutic opportunities to attenuate racial disparities in prostate cancer.

The DNA/RNA helicase DHX9 contributes to the transcriptional program of the androgen receptor in prostate cancer

BackgroundProstate cancer (PC) is the most commonly diagnosed male malignancy and an important cause of mortality. Androgen deprivation therapy is the first line treatment but, unfortunately, a large part of patients evolves to a castration-resistant stage, for which no effective cure is currently available. The DNA/RNA helicase DHX9 is emerging as an important regulator of cellular processes that are often deregulated in cancer.MethodsTo investigate whether DHX9 modulates PC cell transcriptome we performed RNA-sequencing analyses upon DHX9 silencing in the androgen-responsive cell line LNCaP. Bioinformatics and functional analyses were carried out to elucidate the mechanism of gene expression regulation by DHX9. Data from The Cancer Genome Atlas were mined to evaluate the potential role of DHX9 in PC.ResultsWe found that up-regulation of DHX9 correlates with advanced stage and is associated with poor prognosis of PC patients. High-throughput RNA-sequencing analysis revealed that depletion of DHX9 in androgen-sensitive LNCaP cells affects expression of hundreds of genes, which significantly overlap with known targets of the Androgen Receptor (AR). Notably, AR binds to the DHX9 promoter and induces its expression, while Enzalutamide-mediated inhibition of AR activity represses DHX9 expression. Moreover, DHX9 interacts with AR in LNCaP cells and its depletion significantly reduced the recruitment of AR to the promoter region of target genes and the ability of AR to promote their expression in response to 5α-dihydrotestosterone. Consistently, silencing of DXH9 negatively affected androgen-induced PC cell proliferation and migration.ConclusionsCollectively, our data uncover a new role of DHX9 in the control of the AR transcriptional program and establish the existence of an oncogenic DHX9/AR axis, which may represent a new druggable target to counteract PC progression.

PD07-10 STROMAL ANDROGEN RECEPTOR INHIBITS PROSTATE TUMOR PROGRESSION BY RESTRAINING SECRETORY LUMINAL EPITHELIAL CELLS

You have accessJournal of UrologyCME1 May 2022PD07-10 STROMAL ANDROGEN RECEPTOR INHIBITS PROSTATE TUMOR PROGRESSION BY RESTRAINING SECRETORY LUMINAL EPITHELIAL CELLS Zhu Wang, Yueli Liu, Jiawen Wang, Corrigan Horton, Joshua Stefanson, and Qing Xie Zhu WangZhu Wang More articles by this author , Yueli LiuYueli Liu More articles by this author , Jiawen WangJiawen Wang More articles by this author , Corrigan HortonCorrigan Horton More articles by this author , Joshua StefansonJoshua Stefanson More articles by this author , and Qing XieQing Xie More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002526.10AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Androgen receptor (AR) is expressed in both the prostate epithelium and stroma, and plays cell-type-specific roles in development and prostate cancer (PCa). While it is well established that stromal AR is required for epithelial cell growth in prostate development, how it affects PCa progression remains unclear. Clinically, lower expression of stromal AR is associated with advanced PCa and worse patient outcome. Yet several renal grafting and mouse model studies reported a role for stromal AR in promoting PCa progression. The discrepancy may be attributed to a negligence of developmental vs adult prostate stages in previous studies. The objective of this study is to clarify the role of stromal AR in PCa using rigorous mouse model designs and investigate its mechanism. METHODS: We deleted stromal AR strictly at adult stage by tamoxifen-inducing the Myh11-CreERT2 line in the Hi-Myc and the hormonal carcinogenesis T+E2 mouse models (named strAR-Myc and strAR-T+E, respectively, as experimental groups). Myc and T+E mice with wildtype stroma served as controls. We assessed tumor histology for both models through time by H&E and assigned a score for each sample in a double-blind setting. Experimental and control groups were compared using two-sided t-test. We next performed single cell RNA-seq (scRNA-seq) of T+E and strAR-T+E samples to determine which cell type was altered and used gene set enrichment analysis (GSEA) to determine the affected molecular pathway. RESULTS: Fig A shows that stromal AR loss consistently resulted in higher H&E scores (more aggressive) in both models. UMAP in Fig B shows that secretory luminal cells were particularly altered by stromal AR loss. GSEA analyses of multiple datasets revealed that the PI3K pathway was potentiated in a subset luminal cells of the strAR-T+E tumor. CONCLUSIONS: Stromal AR normally inhibits PCa progression by restraining the PI3K activity within luminal tumor cells. This implies that conventional androgen deprivation therapy may have unintended negative consequence due to stromal AR loss. Source of Funding: NIH R01GM116872 © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e102 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Zhu Wang More articles by this author Yueli Liu More articles by this author Jiawen Wang More articles by this author Corrigan Horton More articles by this author Joshua Stefanson More articles by this author Qing Xie More articles by this author Expand All Advertisement PDF DownloadLoading ...

The Role of Androgen Receptor and microRNA Interactions in Androgen-Dependent Diseases.

The androgen receptor (AR) is a member of the steroid hormone receptor family of nuclear transcription factors. It is present in the primary/secondary sexual organs, kidneys, skeletal muscles, adrenal glands, skin, nervous system, and breast. Abnormal AR functioning has been identified in numerous diseases, specifically in prostate cancer (PCa). Interestingly, recent studies have indicated a relationship between the AR and microRNA (miRNA) crosstalk and cancer progression. MiRNAs are small, endogenous, non-coding molecules that are involved in crucial cellular processes, such as proliferation, apoptosis, or differentiation. On the one hand, AR may be responsible for the downregulation or upregulation of specific miRNA, while on the other hand, AR is often a target of miRNAs due to their regulatory function on AR gene expression. A deeper understanding of the AR–miRNA interactions may contribute to the development of better diagnostic tools as well as to providing new therapeutic approaches. While most studies usually focus on the role of miRNAs and AR in PCa, in this review, we go beyond PCa and provide insight into the most recent discoveries about the interplay between AR and miRNAs, as well as about other AR-associated and AR-independent diseases.

GLI3 Is Stabilized by SPOP Mutations and Promotes Castration Resistance via Functional Cooperation with Androgen Receptor in Prostate Cancer.

Although the Sonic hedgehog (SHH) signaling pathway has been implicated in promoting malignant phenotypes of prostate cancer, details on how it is activated and exerts its oncogenic role during prostate cancer development and progression is less clear. Here, we show that GLI3, a key SHH pathway effector, is transcriptionally upregulated during androgen deprivation and posttranslationally stabilized in prostate cancer cells by mutation of speckle-type POZ protein (SPOP). GLI3 is a substrate of SPOP-mediated proteasomal degradation in prostate cancer cells and prostate cancer driver mutations in SPOP abrogate GLI3 degradation. Functionally, GLI3 is necessary and sufficient for the growth and migration of androgen receptor (AR)-positive prostate cancer cells, particularly under androgen-depleted conditions. Importantly, we demonstrate that GLI3 physically interacts and functionally cooperates with AR to enrich an AR-dependent gene expression program leading to castration-resistant growth of xenografted prostate tumors. Finally, we identify an AR/GLI3 coregulated gene signature that is highly correlated with castration-resistant metastatic prostate cancer and predictive of disease recurrence. Together, these findings reveal that hyperactivated GLI3 promotes castration-resistant growth of prostate cancer and provide a rationale for therapeutic targeting of GLI3 in patients with castration-resistant prostate cancer (CRPC). IMPLICATIONS: We describe two clinically relevant mechanisms leading to hyperactivated GLI3 signaling and enhanced AR/GLI3 cross-talk, suggesting that GLI3-specific inhibitors might prove effective to block prostate cancer development or delay CRPC.

Androgen receptor regulates eIF5A2 expression and promotes prostate cancer metastasis via EMT

Androgen receptor (AR) is an androgen-activated transcription factor of the nuclear receptor superfamily. AR plays a role in the development and progression of prostate cancer (PCa). However, the exact role of AR in PCa metastasis remains unclear. In the present study, we aimed to elucidate the function of AR in PCa. We found that eukaryotic translation initiation factor (EIF) 5A2, an elongation factor that induces epithelial-to-mesenchymal transition (EMT) in PCa cells, was significantly upregulated after 5α-dihydrotestosterone (DHT) stimulation and downregulated after anti‐androgen bicalutamide treatment in PCa cells with high AR expression, but not in cells with low AR expression. Moreover, eIF5A2 knockdown could eliminate DHT-induced invasion and migration of AR-positive PCa cells. DHT treatment decreased epithelial expression of E‐cadherin and β-catenin but increased the expression of the mesenchymal marker proteins Vimentin and N-cadherin. DHT therefore induced EMT, and knockdown of eIF5A2 inhibited DHT-induced EMT. Moreover, in vivo study, Luciferase signals from the lungs of the eIF5A2 plasmid group indicated higher metastasis ability, and the eIF5A2 siRNA group had lower metastasis ability. Our results suggest that AR positively regulates eIF5A2 expression in androgen-dependent cells, and stimulation of AR expression and signaling in prostate tumors promotes PCa metastasis by EMT induction and upregulation of eIF5A2.

Single-cell analysis reveals androgen receptor regulates the ER-to-Golgi trafficking pathway with CREB3L2 to drive prostate cancer progression.

Androgen receptor (AR) plays a central role in driving prostate cancer (PCa) progression. How AR promotes this process is still not completely clear. Herein, we used single-cell transcriptome analysis to reconstruct the transcriptional network of AR in PCa. Our work shows AR directly regulates a set of signature genes in the ER-to-Golgi protein vesicle-mediated transport pathway. The expression of these genes is required for maximum androgen-dependent ER-to-Golgi trafficking, cell growth, and survival. Our analyses also reveal the signature genes are associated with PCa progression and prognosis. Moreover, we find inhibition of the ER-to-Golgi transport process with a small molecule enhanced antiandrogen-mediated tumor suppression of hormone-sensitive and insensitive PCa. Finally, we demonstrate AR collaborates with CREB3L2 in mediating ER-to-Golgi trafficking in PCa. In summary, our findings uncover a critical role for dysregulation of ER-to-Golgi trafficking expression and function in PCa progression, provide detailed mechanistic insights for how AR tightly controls this process, and highlight the prospect of targeting the ER-to-Golgi pathway as a therapeutic strategy for advanced PCa.