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PLZF, a tumor suppressor genetically lost in metastatic castration-resistant prostate cancer, is a mediator of resistance to androgen deprivation therapy.

ABSTRACT: Whole-exome sequencing of metastatic castration-resistant prostate cancer (mCRPC) reveals that 5% to 7% of tumors harbor promyelocytic leukemia zinc finger (PLZF) protein homozygous deletions. PLZF is a canonical androgen-regulated putative tumor suppressor gene whose expression is inhibited by androgen deprivation therapy (ADT). Here, we demonstrate that knockdown of PLZF expression promotes a CRPC and enzalutamide-resistant phenotype in prostate cancer cells. Reintroduction of PLZF expression is sufficient to reverse androgen-independent growth mediated by PLZF depletion. PLZF loss enhances CRPC tumor growth in a xenograft model. Bioinformatic analysis of the PLZF cistrome shows that PLZF negatively regulates multiple pathways, including the MAPK pathway. Accordingly, our data support an oncogenic program activated by ADT. This acquired mechanism together with the finding of genetic loss in CRPC implicates PLZF inactivation as a mechanism promoting ADT resistance and the CRPC phenotype.

SUBMITTER: Hsieh CL

PROVIDER: S-EPMC4433564 | biostudies-literature | 2015 May

REPOSITORIES: biostudies-literature

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PLZF, a tumor suppressor genetically lost in metastatic castration-resistant prostate cancer, is a mediator of resistance to androgen deprivation therapy.

Hsieh Chen-Lin CL Botta Ginevra G Gao Shuai S Li Tiantian T Van Allen Eliezer M EM Treacy Daniel J DJ Cai Changmeng C He Housheng Hansen HH Sweeney Christopher J CJ Brown Myles M Balk Steven P SP Nelson Peter S PS Garraway Levi A LA Kantoff Philip W PW

Cancer research 20150325 10

Whole-exome sequencing of metastatic castration-resistant prostate cancer (mCRPC) reveals that 5% to 7% of tumors harbor promyelocytic leukemia zinc finger (PLZF) protein homozygous deletions. PLZF is a canonical androgen-regulated putative tumor suppressor gene whose expression is inhibited by androgen deprivation therapy (ADT). Here, we demonstrate that knockdown of PLZF expression promotes a CRPC and enzalutamide-resistant phenotype in prostate cancer cells. Reintroduction of PLZF expression ...[more]

PMID: 25808865

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Project description:Plasma androgen receptor (AR) gain identifies metastatic castration-resistant prostate cancer (mCRPC) patients with worse outcome on abiraterone/enzalutamide, but its relevance in the context of taxane chemotherapy is unknown. We aimed to evaluate whether docetaxel is active regardless of plasma AR and to perform an exploratory analysis to compare docetaxel with abiraterone/enzalutamide. This multi-institutional study was a pooled analysis of AR status, determined by droplet digital polymerase chain reaction, on pretreatment plasma samples. We evaluated associations between plasma AR and overall/progression-free survival (OS/PFS) and prostate-specific antigen (PSA) response rate in 163 docetaxel-treated patients. OS was significantly shorter in case of AR gain (hazard ratio [HR]=1.61, 95% confidence interval [CI]=1.08-2.39, p=0.018), but not PFS (HR=1.04, 95% CI 0.74-1.46, p=0.8) or PSA response (odds ratio=1.14, 95% CI=0.65-1.99, p=0.7). We investigated the interaction between plasma AR and treatment type after incorporating updated data from our prior study of 73 chemotherapy-naïve, abiraterone/enzalutamide-treated patients, with data from 115 first-line docetaxel patients. In an exploratory analysis of mCRPC patients receiving first-line therapies, a significant interaction was observed between plasma AR and docetaxel versus abiraterone/enzalutamide for OS (HR=0.16, 95% CI=0.06-0.46, p<0.001) and PFS (HR=0.31, 95% CI=0.12-0.80, p=0.02). Specifically, we reported a significant difference for OS favoring abiraterone/enzalutamide for AR-normal patients (HR=1.93, 95% CI=1.19-3.12, p=0.008) and a suggestion favoring docetaxel for AR-gained patients (HR=0.53, 95% CI=0.24-1.16, p=0.11). These data suggest that AR-normal patients should receive abiraterone/enzalutamide and AR-gained could benefit from docetaxel. This treatment selection merits prospective evaluation in a randomized trial. PATIENT SUMMARY: We investigated whether plasma androgen receptor (AR) predicted outcome in metastatic castration-resistant prostate cancer (mCRPC) patients treated with docetaxel, and we performed an exploratory analysis in patients treated with docetaxel or AR-directed drugs as first-line mCRPC therapy. We showed that plasma AR normal favored hormonal treatment, whilst plasma AR-gained patients may have had a longer response to docetaxel, suggesting that plasma AR status could be a useful treatment selection biomarker.

Project description:BackgroundAndrogen deprivation therapy (ADT) for prostate cancer with luteinizing hormone-releasing hormone (LHRH) agonists can be improved.ObjectiveTo assess safety, the frequency and severity of hot flushes (HFs), bone health, and antitumor effects of high-dose estetrol (HDE4) when combined with ADT.Design setting and participantsA phase II, double-blind, randomized, placebo-controlled study was conducted in advanced prostate cancer patients requiring ADT (the PCombi study).InterventionPatients receiving LHRH agonist treatment were randomized 2:1 to 40 mg HDE4 (n = 41) or placebo (n = 21) cotreatment for 24 wk.Outcome measurements and statistical analysisCoprimary endpoints were frequency/severity of HFs and levels of total and free testosterone (T). Secondary endpoints included assessments of bone metabolism (osteocalcin and type I collagen telopeptide [CTX1]), prostate-specific antigen (PSA), and follicle-stimulating hormone (FSH). Efficacy analysis was based on the selected per-protocol (PP) population.Results and limitationsOf 62 patients included in the study, 57 were suitable for a PP analysis (37 HDE4; 20 placebo). No E4-related serious cardiovascular adverse events occurred at 24 wk. Weekly HFs were reported by 13.5% of patients with HDE4 and 60.0% with placebo (p < 0.001). Daily HFs occurred in 5.9% versus 55%. Bone turnover parameters decreased significantly with HDE4 (p < 0.0001). Total and free T decreased earlier (p < 0.05), and free T was suppressed further (p < 0.05). PSA suppression was more profound and earlier (p < 0.005). FSH levels were suppressed by 98% versus 57% (p < 0.0001). Estrogenic side effects were nipple sensitivity (34%) and gynecomastia (17%).ConclusionsHDE4 cotreatment of ADT patients with advanced prostate cancer was well tolerated, and no treatment-related cardiovascular adverse events were observed at 24 wk. HFs and bone turnover were substantially reduced. Suppression of free T, PSA, and FSH was more rapid and profound, suggesting enhanced disease control by HDE4 cotreatment. Larger and longer-lasting studies are needed to confirm the results of the study reported here.Patient summaryCotreatment of androgen deprivation therapy with high-dose estetrol in advanced prostate cancer patients results in fewer occurrences of hot flushes, bone protection, and other antitumor benefits. Nipple sensitivity and gynecomastia may occur as side effects.

Dataset Information

PLZF, a tumor suppressor genetically lost in metastatic castration-resistant prostate cancer, is a mediator of resistance to androgen deprivation therapy.

Publications

PLZF, a tumor suppressor genetically lost in metastatic castration-resistant prostate cancer, is a mediator of resistance to androgen deprivation therapy.

Similar Datasets

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