scholarly journals Inhibition of Androgen Receptor Transcriptional Activity as a Novel Mechanism of Action of Arsenic

2009 ◽  
Vol 23 (3) ◽  
pp. 412-421 ◽  
Author(s):  
Adena E. Rosenblatt ◽  
Kerry L. Burnstein
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Male Infertility ◽  
Transcriptional Activity ◽  
Target Gene ◽  
Nuclear Translocation ◽  
Therapeutic Option ◽  
Protein Levels

Abstract Environmental sodium arsenite is a toxin that is associated with male infertility due to decreased and abnormal sperm production. Arsenic trioxide (ATO), another inorganic trivalent semimetal, is an effective therapy for acute promyelocytic leukemia, and there is investigation of its possible efficacy in prostate cancer. However, the mechanism of arsenic action in male urogenital tract tissues is not clear. Because the androgen receptor (AR) plays an important role in spermatogenesis and prostate cancer, we explored the possibility that trivalent arsenic regulates AR function. We found that arsenic inhibited AR transcriptional activity in prostate cancer and Sertoli cells using reporter gene assays testing several androgen response element-containing regions and by assessing native target gene expression. Arsenic inhibition of AR activity was not due to down-regulation of AR protein levels, decreased hormone binding to AR, disruption of AR nuclear translocation, or interference with AR-DNA binding in vitro. However, chromatin immunoprecipitation studies revealed that arsenic inhibited AR recruitment to an AR target gene enhancer in vivo. Consistent with a deficiency in AR-chromatin binding, arsenic disrupted AR amino and carboxyl termini interaction. Furthermore, ATO caused a significant decrease in prostate cancer cell proliferation that was more pronounced in cells expressing AR compared with cells depleted of AR. In addition, inhibition of AR activity by ATO and by the AR antagonist, bicalutamide, was additive. Thus, arsenic-induced male infertility may be due to inhibition of AR activity. Further, because AR is an important target in prostate cancer therapy, arsenic may serve as an effective therapeutic option.

scholarly journals Essential Role for Co-chaperone Fkbp52 but Not Fkbp51 in Androgen Receptor-mediated Signaling and Physiology

2006 ◽  
Vol 282 (7) ◽  
pp. 5026-5036 ◽  
Author(s):  
Weidong Yong ◽  
Zuocheng Yang ◽  
Sumudra Periyasamy ◽  
Hanying Chen ◽  
Selcul Yucel ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Transcriptional Activity ◽  
Target Gene ◽  
Nuclear Translocation ◽  
Steroid Receptor ◽  
Hormone Binding ◽  
Receptor Complexes ◽  
Deficient Mice

Fkbp52 and Fkbp51 are tetratricopeptide repeat proteins found in steroid receptor complexes, and Fkbp51 is an androgen receptor (AR) target gene. Although in vitro studies suggest that Fkbp52 and Fkbp51 regulate hormone binding and/or subcellular trafficking of receptors, the roles of Fkbp52 and Fkbp51 in vivo have not been extensively investigated. Here, we evaluate their physiological roles in Fkbp52-deficient and Fkbp51-deficient mice. Fkbp52-deficient males developed defects in select reproductive organs (e.g. penile hypospadias and prostate dysgenesis but normal testis), pointing to a role for Fkbp52 in AR-mediated signaling and function. Surprisingly, ablation of Fkbp52 did not affect AR hormone binding or nuclear translocation in vivo and in vitro. Molecular studies in mouse embryonic fibroblast cells uncovered that Fkbp52 is critical to AR transcriptional activity. Interestingly, Fkbp51 expression was down-regulated in Fkbp52-deficient males but only in affected tissues, providing further evidence of tissue-specific loss of AR activity and suggesting that Fkbp51 is an AR target gene essential to penile and prostate development. However, Fkbp51-deficient mice were normal, showing no defects in AR-mediated reproductive function. Our work demonstrates that Fkbp52 but not Fkbp51 is essential to AR-mediated signaling and provides evidence for an unprecedented Fkbp52 function, direct control of steroid receptor transcriptional activity.

scholarly journals Huaier Extract Inhibits Prostate Cancer Growth via Targeting AR/AR-V7 Pathway

2021 ◽  
Vol 11 ◽  
Author(s):  
Zhengfang Liu ◽  
Cheng Liu ◽  
Keqiang Yan ◽  
Jikai Liu ◽  
Zhiqing Fang ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Nuclear Translocation ◽  
Mrna Levels ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant ◽  
Specific Protease ◽  
Hormone Sensitive

The androgen receptor (AR) plays a pivotal role in prostatic carcinogenesis, and it also affects the transition from hormone sensitive prostate cancer (HSPC) to castration-resistant prostate cancer (CRPC). Particularly, the persistent activation of the androgen receptor and the appearance of androgen receptor splicing variant 7 (AR-V7), could partly explain the failure of androgen deprivation therapy (ADT). In the present study, we reported that huaier extract, derived from officinal fungi, has potent antiproliferative effects in both HSPC and CRPC cells. Mechanistically, huaier extract downregulated both full length AR (AR-FL) and AR-V7 mRNA levels via targeting the SET and MYND domain-containing protein 3 (SMYD3) signaling pathway. Huaier extract also enhanced proteasome-mediated protein degradation of AR-FL and AR-V7 by downregulating proteasome-associated deubiquitinase ubiquitin-specific protease 14 (USP14). Furthermore, huaier extract inhibited AR-FL/AR-V7 transcriptional activity and their nuclear translocation. More importantly, our data demonstrated that huaier extract could re-sensitize enzalutamide-resistant prostate cancer cells to enzalutamide treatment in vitro and in vivo models. Our work revealed that huaier extract could be effective for treatment of prostate cancer either as monotherapy or in combination with enzalutamide.

ODM-204: A novel dual inhibitor of CYP17A1 and androgen receptor for the treatment of castration-resistant prostate cancer—Preclinical data.

2015 ◽  
Vol 33 (7_suppl) ◽  
pp. 221-221
Author(s):  
Riikka Oksala ◽  
Anu Moilanen ◽  
Reetta Riikonen ◽  
Petteri Rummakko ◽  
Riikka Huhtaniemi ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Nuclear Translocation ◽  
Leuprolide Acetate ◽  
Male Rats ◽  
Castration Resistant Prostate Cancer ◽  
Dual Inhibitor ◽  
Castration Resistant

221 Background: Castration-resistant prostate cancer (CRPC) is characterized by high androgen receptor (AR) expression and persistent activation of AR signaling axis by residual tissue/tumor androgens. Targeting AR and androgen biosynthesis together may be more effective than either alone. ODM-204 is a novel, non-steroidal dual inhibitor of CYP17A1 and AR, which has shown promising results in preclinical studies. Methods: The binding affinity of ODM-204 to wild type AR was determined in rat prostate cytosolic lysates. The potency and functional activity of ODM-204 to human AR were demonstrated in cells stably transfected with the full-length AR and androgen-responsive reporter gene constructs. In addition, assays for AR nuclear translocation and the transactivation of human AR mutants T877A, W741L, and F876L were conducted. The effects of ODM-204 on the growth of androgen-dependent VCaP and LNCaP cells in vitro and subcutaneously grafted VCaP cells in vivo with the oral dose of 50 mg/kg/day were studied. The inhibition of CYP17A1 by ODM-204 was studied in vitro by using human and rat testicular microsomes and a human adrenal cortex cell line, and in vivo in male rats coadministered with luteinizing hormone releasing hormone agonist leuprolide acetate to mimic clinical situation. Results: ODM-204 is a potent inhibitor of both AR and CYP17A1. It binds to AR with a high affinity (Ki=47 nM) and selectivity and has a high potency towards CYP17A1 (IC50=22 nM). In addition, ODM-204 inhibited testosterone-mediated nuclear translocation of AR and the mutant ARs (IC50 values for AR(T877A), AR(W741L), and AR(F876L) were 95, 277, and 6 nM, respectively), and suppressed androgen-induced cell proliferation of LNCaP (IC50=170 nM) and VCaP (IC50=280 nM) cells. In a VCaP xenograft model, ODM-204 showed significant antitumor activity (tumor growth inhibition=66%). In rats, inhibitory effects of leuprolide acetate on testosterone production and androgen-sensitive organ weights were potentiated by ODM-204. Conclusions: ODM-204 is a promising new dual CYP17A1 and AR inhibitor for the treatment of CRPC. Clinical trials in patients with mCRPC will be started in early 2015.

ARV-330: Androgen receptor PROTAC degrader for prostate cancer.

2016 ◽  
Vol 34 (2_suppl) ◽  
pp. 267-267 ◽  
Author(s):  
Taavi K Neklesa ◽  
Meizhong Jin ◽  
Andrew P Crew ◽  
AnnMarie K Rossi ◽  
Ryan R Willard ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Therapeutic Effects ◽  
Preclinical Development ◽  
Protein Levels ◽  
Novel Approach ◽  
Subsequent Degradation ◽  
20 Nm

267 Background: The transition from localized prostate cancer to metastatic disease often involves modulation of the Androgen Receptor (AR). During the disease progression, patients progressing on enzalutamide or abiraterone therapy exhibit amplified AR, increased intra-tumoral androgen production or AR mutations leading to promiscuity to other ligands. Therefore, AR is still the principal driver of the disease. Methods: A novel approach to block AR signaling is to specifically target AR for degradation. To this end, we have developed the PROteolysis TArgeting Chimera (PROTAC) technology that employs hetero-bifunctional small molecules that simultaneously bind VHL E3 ubiquitin ligase and a target of interest (e.g. AR). Due to induced proximity between VHL and AR, an AR PROTAC leads to ubiquitination and subsequent degradation of AR. Results: Our lead AR PROTAC, ARV-330, degrades 92-98% of total AR in all cell lines tested, with 50% degradation concentrations (DC50) < 1nM. AR degradation suppresses the AR-target gene PSA expression, inhibits proliferation, and induces potent apoptosis in VCaP cells with maximal apoptosis observed at 20 nM. While enzalutamide loses its activity in the presence of > 0.5 nM R1881, ARV-330 maintains its activity. In cells containing the ARF876L mutation, enzalutamide is an agonist; however, ARV-330 remains effective. In fact, ARV-330 is able to degrade all clinically relevant AR mutations. ARV-330 exhibits good pharmacokinetic properties, with t1/2 values of several hours and bioavailability of > 80% after sc injection. Treatment of mice with ARV-330, at doses ranging from 0.3 to 10 mg/kg, results in reduction of AR protein levels. The in vitro potency translates into in vivo efficacy, as ARV-330 demonstrates prostate involution in intact mice. In castrated mice implanted with VCaP tumors, ARV-330 shows robust reduction of plasma PSA and blockade of tumor growth. Conclusions: In summary, the AR PROTAC ARV-330 removes AR from prostate cancer cells in a potent manner and produces therapeutic effects as a result. This cellular efficacy has translated into biomarker activity and efficacy in animal models, and ARV-330 is now in preclinical development.

ARV-110: An oral androgen receptor PROTAC degrader for prostate cancer.

2019 ◽  
Vol 37 (7_suppl) ◽  
pp. 259-259 ◽  
Author(s):  
Taavi Neklesa ◽  
Lawrence B Snyder ◽  
Ryan R Willard ◽  
Nicholas Vitale ◽  
Jennifer Pizzano ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Target Gene ◽  
Point Mutations ◽  
Genetic Alterations ◽  
Significant Inhibition ◽  
Castration Resistant Prostate Cancer ◽  
Orally Bioavailable

259 Background: The Androgen Receptor (AR) remains the principal driver of castration-resistant prostate cancer during the transition from a localized to metastatic disease. Most patients initially respond to inhibitors of the AR pathway, but the response is often relatively short-lived. The majority of patients progressing on enzalutamide or abiraterone exhibit genetic alterations in the AR locus, either in the form of amplifications or point mutations in the AR gene. Given these mechanisms of resistance, our goal is to eliminate the AR protein using the PROteolysis TArgeting Chimera (PROTAC) technology. Methods: Here we report an orally bioavailable small molecule AR PROTAC degrader, ARV-110, that promotes ubiquitination and degradation of AR. This molecule has been characterized in in vitro degradation and functional assays, and DMPK, toxicology and preclinical efficacy studies. Results: ARV-110 robustly degrades AR in all cell lines tested, with an observed half-maximal degradation concentration (DC50) of ~1 nM. ARV-110 treatment leads to highly selective AR degradation, as demonstrated by proteomic studies. In VCaP cells, PROTAC-mediated AR degradation suppresses the expression of the AR-target gene PSA, inhibits AR-dependent cell proliferation, and induces apoptosis at low nanomolar concentrations. Further, ARV-110 degrades clinically relevant mutant AR proteins and retains activity in a high androgen environment. In mouse xenograft studies, greater than 90% AR degradation is observed at a 1 mg/kg PO QD dose. Significant inhibition of tumor growth and AR signaling has been achieved in LNCaP, VCaP and prostate cancer patient derived xenograft (PDX) models. Notably, ARV-110 demonstrates in vivo efficacy and reduction of AR-target gene expression in a long term, castrate, enzalutamide-resistant VCaP tumor model. Conclusions: In summary, we report preclinical data on an orally bioavailable AR PROTAC degrader, ARV-110, that demonstrates efficacy in multiple prostate cancer models. ARV-110 has completed IND-enabling studies and FIH studies are planned for 1Q2019.

scholarly journals ARVib suppresses growth of advanced prostate cancer via inhibition of androgen receptor signaling

Oncogene ◽  
2021 ◽  
Author(s):  
Chengfei Liu ◽  
Cameron M. Armstrong ◽  
Shu Ning ◽  
Joy C. Yang ◽  
Wei Lou ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Cancer Progression ◽  
Nuclear Translocation ◽  
Treatment Resistance ◽  
Hsp70 Expression ◽  
Castration Resistant Prostate Cancer ◽  
Downstream Target

AbstractTargeting androgen signaling with the second-generation anti-androgen drugs, such as enzalutamide (Enza), abiraterone (Abi), apalutamide (Apal), and darolutamide (Daro), is the mainstay for the treatment of castration-resistant prostate cancer (CRPC). While these treatments are effective initially, resistance occurs frequently. Continued expression of androgen receptor (AR) and its variants such as AR-V7 despite AR-targeted therapy contributes to treatment resistance and cancer progression in advanced CRPC patients. This highlights the need for new strategies blocking continued AR signaling. Here, we identify a novel AR/AR-V7 degrader (ARVib) and found that ARVib effectively degrades AR/AR-V7 protein and attenuates AR/AR-V7 downstream target gene expression in prostate cancer cells. Mechanistically, ARVib degrades AR/AR-V7 protein through the ubiquitin-proteasome pathway mediated by HSP70/STUB1 machinery modulation. ARVib suppresses HSP70 expression and promotes STUB1 nuclear translocation, where STUB1 binds to AR/AR-V7 and promotes its ubiquitination and degradation. ARVib significantly inhibits resistant prostate tumor growth and improves enzalutamide treatment in vitro and in vivo. These data suggest that ARVib has potential for development as an AR/AR-V7 degrader to treat resistant CRPC.

scholarly journals Novel Thienopyrimidine Derivative, RP-010, Induces β-Catenin Fragmentation and Is Efficacious against Prostate Cancer Cells

Cancers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 711 ◽  
Author(s):  
Haneen Amawi ◽  
Noor Hussein ◽  
Sai H. S. Boddu ◽  
Chandrabose Karthikeyan ◽  
Frederick E. Williams ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cancer Cells ◽  
Cell Lines ◽  
Nuclear Translocation ◽  
Wide Spectrum ◽  
Thiophene Ring ◽  
Mitotic Catastrophe ◽  
Prostate Cancer Cells

Thienopyrimidines containing a thiophene ring fused to pyrimidine are reported to have a wide-spectrum of anticancer efficacy in vitro. Here, we report for the first time that thieno[3,2-d]pyrimidine-based compounds, also known as the RP series, have efficacy in prostate cancer cells. The compound RP-010 was efficacious against both PC-3 and DU145 prostate cancer (PC) cells (IC50 < 1 µM). The cytotoxicity of RP-010 was significantly lower in non-PC, CHO, and CRL-1459 cell lines. RP-010 (0.5, 1, 2, and 4 µM) arrested prostate cancer cells in G2 phase of the cell cycle, and induced mitotic catastrophe and apoptosis in both PC cell lines. Mechanistic studies suggested that RP-010 (1 and 2 µM) affected the wingless-type MMTV (Wnt)/β-catenin signaling pathway, in association with β-catenin fragmentation, while also downregulating important proteins in the pathway, including LRP-6, DVL3, and c-Myc. Interestingly, RP-010 (1 and 2 µM) induced nuclear translocation of the negative feedback proteins, Naked 1 and Naked 2, in the Wnt pathway. In addition, RP-010 (0.5, 1, 2 and 4 µM) significantly decreased the migration of PC cells in vitro. Finally, RP-010 did not produce significant toxic effects in zebrafish at concentrations of up to 6 µM. In conclusion, RP-010 may be an efficacious and relatively nontoxic anticancer compound for prostate cancer. Future mechanistic and in vivo efficacy studies are needed to optimize the hit compound RP-010 for lead optimization and clinical use.

A randomized, open-label, phase II study of MDV3100 alone or in combination with leuprolide and dutasteride as neoadjuvant therapy to prostatectomy in intermediate and high-risk prostate cancer.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. TPS4695-TPS4695 ◽  
Author(s):  
Robert B. Montgomery ◽  
Anthony Joshua ◽  
Alison L. Hannah ◽  
Amy C. Peterson ◽  
Christian Lopez ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Radical Prostatectomy ◽  
Cancer Survival ◽  
Nuclear Translocation ◽  
Systemic Disease ◽  
Complete Response ◽  
Open Label ◽  
Androgen Levels

TPS4695 Background: MDV3100 is a potent androgen receptor (AR) signaling inhibitor (ARSI) that inhibits AR signaling via three mechanisms: inhibition of androgen binding to AR, inhibition of AR nuclear translocation, and inhibition of nuclear AR-DNA binding. In vivo, MDV3100 induces significant prostate cancer apoptosis, an effect not seen with anti-androgens. To date, the use of neoadjuvant androgen deprivation therapy has not led to an improvement in time to PSA progression (Soloway 2002; Aus 2002). While serum androgens may be suppressed using luteinizing hormone-releasing hormone agonists, intratumoral levels of androgens remain, driving continued AR signaling and prostate cancer survival. More effective inhibition of AR signaling may improve local and systemic disease control. Methods: MDV3100-07 will assess the effect of 6 mos of neoadjuvant AR blockade with AR inhibition alone (MDV3100) or in combination with maximal suppression of androgens (MDV3100 +leuprolide [L] + dutasteride [D]). Eligible patients will have treatment-naive localized prostate cancer and be candidates for radical prostatectomy. Patients must have either PSA > 10 ng/mL or Gleason score ≥ 7 (4 + 3) with ≥3 cores containing tumor. Patients with evidence of metastatic/nodal disease are excluded. All patients receive MDV3100 (160 mg/d PO); those randomized to MDV3100+L+D therapy also receive L (22.5mg IM q3m) and D (0.5 mg/day PO). Serum/tumor androgen levels will be serially assessed. Tissue from the diagnostic and prostatectomy specimens will be evaluated for androgen levels, AR signaling profiles, and selected markers of apoptosis and mitotic indices. The primary efficacy endpoint is pathological complete response (pCR) rate at time of radical prostatectomy. For each arm, the percent of patients who achieve a pCR will be compared to the percent pCR in patients treated with neoadjuvant leuprolide, estimated to be 5% in a mixed low-to-intermediate risk population. Target Accrual: 40 pts will be randomized 1:1 to MDV3100 or MDV3100+L+D therapy. Keywords:MDV3100, prostate cancer, androgen receptor, anti-androgen, Phase 2, neoadjuvant.

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