Proteostasis by STUB1/HSP70 complex controls sensitivity to androgen receptor targeted therapy in advanced prostate cancer.

Protein homeostasis (proteostasis) is a potential mechanism that contributes to cancer cell survival and drug resistance. Constitutively active androgen receptor (AR) variants confer anti-androgen resistance in advanced prostate cancer. However, the role of proteostasis involved in next generation anti-androgen resistance and the mechanisms of AR variant regulation are poorly defined. Here we show that the ubiquitin-proteasome-system (UPS) is suppressed in enzalutamide/abiraterone resistant prostate cancer. AR/AR-V7 proteostasis requires the interaction of E3 ubiquitin ligase STUB1 and HSP70 complex. STUB1 disassociates AR/AR-V7 from HSP70, leading to AR/AR-V7 ubiquitination and degradation. Inhibition of HSP70 significantly inhibits prostate tumor growth and improves enzalutamide/abiraterone treatments through AR/AR-V7 suppression. Clinically, HSP70 expression is upregulated and correlated with AR/AR-V7 levels in high Gleason score prostate tumors. Our results reveal a novel mechanism of anti-androgen resistance via UPS alteration which could be targeted through inhibition of HSP70 to reduce AR-V7 expression and overcome resistance to AR-targeted therapies

Hematologic Toxicity of Concurrent Administration of Radium-223 and Next-generation Antiandrogen Therapies.

PURPOSE/OBJECTIVES: Radium-223 is a first-in-class radiopharmaceutical recently approved for the treatment of castration-resistant prostate cancer in patients with symptomatic bone metastases. Initial studies investigating Radium-223 primarily used nonsteroidal first-generation antiandrogens. Since that time, newer antiandrogen therapies have demonstrated improved survival in patients with castration-resistant prostate cancer. It has been suggested that the rational combination of these newly approved agents with Radium-223 may lead to improved response rates and clinical outcomes. Currently, there is lack of information regarding the safety of concurrent administration of these agents with radiopharmaceuticals. Here, we report on hematologic toxicity findings from our institution in patients receiving concurrent Radium-223 and next-generation antiandrogen therapies with either enzalutamide or abiraterone. MATERIALS/METHODS: In a retrospective study, we analyzed patients who received Radium-223 as part of an early-access trial, and following FDA approval in May 2013, patients receiving Radium-223 as part of standard care. Radium-223 was given at standard dosing of 50 kBq/kg each month for 6 total cycles. Complete blood counts were performed before treatment monthly and following each injection. Blood counts from patients receiving Radium alone and concurrently with next-generation antiandrogens were compared. To date, 25 total patients were analyzed, with a median of 5 monthly doses received per patient. Fourteen patients received concurrent therapy during monthly Radium-223 with either enzalutamide (n=8) or abiraterone (n=6). RESULTS: Six patients expired due to disease progression. Two patients discontinued treatment due to grade 3 myelosuppression. For patients receiving either Radium alone and with concurrent next-generation antiandrogen therapy, there did not appear to be any statistically significant differences between initial and nadir blood counts. Mean change from initial neutrophil count to nadir was 1.9×10/L in patients receiving Radium alone, versus 2.3×10/L in patients receiving concurrent therapy (P=0.77). Mean change from initial hemoglobin value to nadir was 1.5 g/L in patients receiving Radium alone, versus 1.8 g/L in patients receiving concurrent therapy (P=0.31). Mean change from initial platelet count to nadir was 52.3×10 cells/L in patients receiving Radium alone versus 70.6×10 cells/L in patients receiving concurrent therapy (P=0.39). Individual blood counts for each measured laboratory are included in the supplemental data. PSA was stable or decreased in 22% of patients receiving Radium alone versus 35% of patients receiving combination treatment (P=0.24). CONCLUSIONS: Concurrent administration of Radium-223 and next-generation antiandrogen therapies appears to be well tolerated with similar toxicities to standard administration of Radium-223 alone. This particular cohort of patients represents a high-risk, heavily pretreated group of patients with advanced metastatic disease and significant marrow burden. Despite these risk factors, hematologic toxicity was modest and was in the range expected for this risk group based on previous trials. To date, this is the first study investigating the toxicity of combination treatment. Further studies investigating the safety and efficacy of combination treatments are warranted

Environmental concentrations of anti-androgenic pharmaceuticals do not impact sexual disruption in fish alone or in combination with steroid oestrogens

This article has been made available through the Brunel Open Access Publishing Fund.Sexual disruption in wild fish has been linked to the contamination of river systems with steroid oestrogens, including the pharmaceutical 17α-ethinylestradiol, originating from domestic wastewaters. As analytical chemistry has advanced, more compounds derived from the human usage of pharmaceuticals have been identified in the environment and questions have arisen as to whether these additional pharmaceuticals may also impact sexual disruption in fish. Indeed, pharmaceutical anti-androgens have been shown to induce such effects under laboratory conditions. These are of particular interest since anti-androgenic biological activity has been identified in the aquatic environment and is potentially implicated in sexual disruption alone and in combination with steroid oestrogens. Consequently, predictive modelling was employed to determine the concentrations of two anti-androgenic human pharmaceuticals, bicalutamide and cyproterone acetate, in UK sewage effluents and river catchments and their combined impacts on sexual disruption were then assessed in two fish models. Crucially, fish were also exposed to the anti-androgens in combination with steroid oestrogens to determine whether they had any additional impact on oestrogen induced feminisation. Modelling predicted that the anti-androgenic pharmaceuticals were likely to be widespread in UK river catchments. However, their concentrations were not sufficient to induce significant responses in plasma vitellogenin concentrations, secondary sexual characteristics or gross indices in male fathead minnow or intersex in Japanese medaka alone or in combination with steroid oestrogens. However, environmentally relevant mixtures of oestrone, 17β-oestradiol and 17α-ethinylestradiol did induce vitellogenin and intersex, supporting their role in sexual disruption in wild fish populations. Unexpectedly, a male dominated sex ratio (100% in controls) was induced in medaka and the potential cause and implications are briefly discussed, highlighting the potential of non-chemical modes of action on this endpoint

Androgen receptors beyond prostate cancer: an old marker as a new target.

Androgen receptors (ARs) play a critical role in the development of prostate cancer. Targeting ARs results in important salutary effects in this malignancy. Despite mounting evidence that ARs also participate in the pathogenesis and/or progression of diverse tumors, exploring the impact of hormonal manipulation of these receptors has not been widely pursued beyond prostate cancer. This review describes patterns of AR expression in a spectrum of cancers, and the potential to exploit this knowledge in the clinical therapeutic setting

Anti-androgens act jointly in suppressing spiggin concentrations in androgen-primed female three-spined sticklebacks - Prediction of combined effects by concentration addition

This is the post-print version of the final paper published in Aquatic Toxicology. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2013 Elsevier B.V.Increasing attention is being directed at the role played by anti-androgenic chemicals in endocrine disruption of wildlife within the aquatic environment. The co-occurrence of multiple contaminants with anti-androgenic activity highlights a need for the predictive assessment of combined effects, but information about anti-androgen mixture effects on wildlife is lacking. This study evaluated the suitability of the androgenised female stickleback screen (AFSS), in which inhibition of androgen-induced spiggin production provides a quantitative assessment of anti-androgenic activity, for predicting the effect of a four component mixture of anti-androgens. The anti-androgenic activity of four known anti-androgens (vinclozolin, fenitrothion, flutamide, linuron) was evaluated from individual concentration-response data and used to design a mixture containing each chemical at equipotent concentrations. Across a 100-fold concentration range, a concentration addition approach was used to predict the response of fish to the mixture. Two studies were conducted independently at each of two laboratories. By using a novel method to adjust for differences between nominal and measured concentrations, good agreement was obtained between the actual outcome of the mixture exposure and the predicted outcome. This demonstrated for the first time that androgen receptor antagonists act in concert in an additive fashion in fish and that existing mixture methodology is effective in predicting the outcome, based on concentration-response data for individual chemicals. The sensitivity range of the AFSS assay lies within the range of anti-androgenicity reported in rivers across many locations internationally. The approach taken in our study lays the foundations for understanding how androgen receptor antagonists work together in fish and is essential in informing risk assessment methods for complex anti-androgenic mixtures in the aquatic environment.European Commission and Natural Environment Research Council

Oral ethinylestradiol in castration resistent prostate cancer: 10 year experience

To describe our 10-year experience with the use of oral ethinylestradiol in the treatment of metastatic castration-resistant prostate cancer. METHODS: From February 2000 to April 2010, 116 patients with a metastatic castration-resistant prostate cancer were prospectively submitted to oral ethinylestradiol monotherapy. Inclusion criteria were: diagnosis of castration-resistant prostate cancer after failure of at least two lines of androgen deprivation therapy and radiological evidence of metastases. Exclusion criteria were: symptomatic cases with a European Cooperative Oncology Group score >2 and severe or uncontrolled cardiovascular diseases. At inclusion in the study, all patients discontinued the previous androgen deprivation therapy and started oral ethinylestradiol at the daily dose of 1 mg. Aspirin (100 mg/daily) was concomitantly given. RESULTS: The median ethinylestradiol therapy duration was 15.9 months (range 8-36 months), whereas the median follow up of patients was 28 months (range 13-36 months). During ethinylestradiol therapy, a confirmed prostate-specific antigen response was found in 79 patients (70.5%). The median time to prostate-specific antigen progression was 15.10 months (95% confidence interval 13.24-18.76 months). A toxicity requiring treatment cessation was observed in 26 patients (23.2%) at a median time of 16 months (mainly thromboembolism). CONCLUSIONS: Our 10-year experience shows that ethinylestradiol provides a prostate-specific antigen response in a high percentage of patients with metastatic castration-resistant prostate cancer. Cardiovascular toxicity can be managed through accurate patient selection, close follow up and a concomitant anticoagulation therapy

International study into the use of intermittent hormone therapy in the treatment of carcinoma of the prostate : A meta-analysis of 1446 patients

OBJECTIVE: To review pooled phase II data to identify features of different regimens of intermittent hormone therapy (IHT), developed to reduce the morbidity of treating metastatic prostate cancer, and which carries a theoretical advantage of delaying the onset of androgen-independent prostate cancer, (AIPC) that are associated with success, highlighting features which require exploration with prospective trials to establish the best strategies for using this treatment. METHODS: Individual data were collated on 1446 patients with adequate information, from 10 phase II studies with >50 cases, identified through Pubmed. RESULTS: Univariate and multivariate Cox proportional hazard models were developed to predict treatment success with a high degree of statistical success. The prostate-specific antigen (PSA) nadir, the PSA threshold to restart treatment, and medication type and duration, were important predictors of outcome. CONCLUSIONS: The duration of biochemical remission after a period of HT is a durable early indicator of how rapidly AIPC and death will occur, and will make a useful endpoint in future trials to investigate the best ways to use IHT based on the important treatment cycling variables described above. Patients spent a mean of 39% of the time off treatment. The initial PSA level and PSA nadir allow the identification of patients with prostate cancer in whom it might be possible to avoid radical therapy.Peer reviewe

Evidence suggesting that di-n-butyl phthalate has anti-androgenic effects in fish

This article is the pre-print version of the full and final published article.Phthalate ester plasticizers are anti-androgenic in mammals. High doses of certain phthalates consistently interfere with the normal development of male offspring exposed in utero, causing disrupted sperm production, abnormal development of the genitalia, and in some cases infertility. In the environment, phthalates are considered ubiquitous and are commonly measured in aquatic ecosystems at low ng to mu g per litre concentrations. Given the similarity between mammalian and teleost endocrine systems, phthalate esters may be able to cause anti-androgenic endocrine disruption in fish in the wild. In the present study, adult male three-spined sticklebacks (Gasterosteus aculetaus) (n = 8) were exposed to di-n-butyl phthalate (DBP) (0, 15, and 35 mu g DBP/L) for 22 d and analyzed for changes in nesting behavior, plasma androgen concentrations, spiggin concentrations, and steroidogenic gene expression. Plasma testosterone concentrations were significantly higher in males from the 35 mu g DBP/L group compared with the solvent control, whereas plasma 11-ketotestosterone concentrations were not significantly affected. Expression of steroid acute regulatory protein and 3 beta-hydroxysteroid dehydrogenase remained unchanged. Spiggin concentrations were significantly lower in the males exposed to 35 mu g DBP/L. Nest building appeared to be slower in some males exposed to DBP, but this was not statistically significant. These results suggest that DBP has anti-androgenic effects in fish. However, further research is required to firmly establish the consequences of chronic DBP exposure in fish

Phosphorylation of androgen receptors at serine 515 is a potential prognostic marker for triple negative breast cancer

1.7 million cases of breast cancer are diagnosed every year with 522,000 deaths. Molecular classifications of breast cancer have resulted in improved treatments. However, treatments for triple negative breast cancer (TNBC) are lacking. Analysis of molecular targets for TNBC is a priority. One potential candidate is androgen receptor (AR) phosphorylation. This study assessed the role of AR phosphorylation at ser81/ser515 and their two upstream effectors, cyclin-dependent kinase 1 (pCDK1) and extracellular-regulated kinase 1/2 (pERK1/2) in 332 ductal breast cancer patients by immunohistochemistry. pERK1/2 combined with AR-515 associated with improved cancer-specific survival (CSS, p = 0.038), decreased size (p = 0.001), invasive grade (p < 0.001), necrosis (p = 0.003), b-lymphocytes (p = 0.020), molecular subtype (p < 0.001) and estrogen receptor (ER)/progesterone receptor (PR)-status (p < 0.001). The cohort was therefore stratified into ER+ve and ER-ve patients. In ER+ve tumours, pERK1/2 combined with AR-515 associated with improved CSS (p = 0.038), smaller size (p = 0.004), invasive grade (p = 0.001), decreased b-lymphocytes (p = 0.013) and increased plasma cells (p = 0.048). In contrast, in TNBC patients, phosphorylation of AR-515 associated with poorer CSS (p = 0.007). pERK1/2 combined with AR-515 associated with decreased inflammation (p = 0.003), increased tumour stroma (p = 0.003) and tumour budding (p = 0.011), with trends towards decrease CSS (p = 0.065) and macrophage levels (p = 0.093). In Conclusions, AR-515 may be an important regulator of inflammation in breast cancer potential via ERK1/2 phosphorylation. AR-515 is a potential prognostic marker and therapeutic target for TNBC

Effect of antiandrogen flutamide on measures of hepatic regeneration in rats

Male rat liver undergoes a process of demasculinization during hepatic regeneration following partial hepatectomy. The possibility that antiandrogens might potentiate this demasculinization process and in so doing augment the hepatic regenerative response was investigated. Adult male Wistar rats were treated with the antiandrogen flutamide (2 mg/rat/day or 5 mg/rat/day subcutaneously) or vehicle for three days prior to and daily after a 70% partial hepatectomy. At various times after hepatectomy, the liver remnants were removed and weighed. Rates of DNA and polyamine synthesis were assessed by measuring thymidine kinase and ornithine decarboxylase activities, respectively. Hepatic estrogen receptor status and the activity of alcohol dehydrogenase, an androgen-sensitive protein, were measured. Prior to surgery, the administration of 5 mg/day flutamide reduced the hepatic cytosolic androgen receptor activity by 98% and hepatic cytosolic estrogen receptor content by 92% compared to that present in vehicle-treated controls. After hepatectomy, however, all differences in sex hormone receptor activity between the treatment groups were abolished. The rate of liver growth after partial hepatectomy in the three groups was identical. Moreover, hepatectomy-induced increases in ornithine decarboxylase activity and thymidine kinase activity were comparable. These data demonstrate that, although flutamide administration initially alters the sex hormone receptor status of the liver, these affects have no effect on the hepatic regenerative response following a partial hepatectomy. © 1989 Plenum Publishing Corporation