Acquired Resistance to the Second-Generation Androgen Receptor Antagonist Enzalutamide in Castration-Resistant Prostate Cancer
ABSTRACT: Illumina gene array analyses of prostate cancer cell lines that had acquired resistance to Enzalutamide (MDV3100). mRNA analyses of four cell lines (CWR-R1, LAPC-4, LNCaP, and VCAP) cells that were either untreated, treated for 48hrs with Enz (short-term), or continuously grown in Enzalutamide for >6 months.
Project description:Prostate cancer is the most commonly diagnosed and second-most lethal cancer among men in the United States. The vast majority of prostate cancer deaths are due to castration-resistant prostate cancer (CRPC) – the lethal form of the disease that has progressed despite therapies that interfere with activation of androgen receptor (AR) signaling. One emergent resistance mechanism to medical castration is synthesis of intratumoral androgens that activate the AR. This insight led to the development of the AR antagonist enzalutamide. However, resistance to enzalutamide invariably develops, and disease progression is nearly universal. One mechanism of resistance to enzalutamide is an F877L mutation in the AR ligand-binding domain that can convert enzalutamide to an agonist of AR activity. However, mechanisms that contribute to the agonist switch had not been fully clarified, and there were no therapies to block AR F877L. Using cell line models of castration-resistant prostate cancer (CRPC), we determined that cellular androgen content influences enzalutamide agonism of mutant F877L AR. Further, enzalutamide treatment of AR F877L-expressing cell lines recapitulated the effects of androgen activation of F877L AR or wild-type AR. Because the BET bromodomain inhibitor JQ-1 was previously shown to block androgen activation of wild-type AR, we tested JQ-1 in AR F877L-expressing CRPC models. We determined that JQ-1 suppressed androgen or enzalutamide activation of mutant F877L AR and suppressed growth of mutant F877L AR CRPC tumors in vivo, demonstrating a new strategy to treat tumors harboring this mutation. RNA-seq profiles of prostate cancer cell lines to understand gene expression associated with enzalutamide treatment
Project description:Enzalutamide (formerly MDV3100 and available commercially as Xtandi), a novel androgen receptor (AR) signaling inhibitor, blocks the growth of castration-resistant prostate cancer (CRPC) in cellular model systems and was shown in a clinical study to increase survival in patients with metastatic CRPC. Enzalutamide inhibits multiple steps of AR signaling: (1) binding of androgens to AR, (2) AR nuclear translocation, and (3) association of AR with DNA. Here we used Affymetrix human genome microarray technology to investigate the global programme of gene expression of LNCaP cells in response to enzalutamide alone and in the context of DHT-stimulated androgen receptor gene expression. LNCaP cells were grown in RPMI 1640 supplemented with 5% hormone depleted FBS and treated with vehicle (control sample) , DHT (100 nM), enzalutamide (1 or 10 µM) or DHT (100 nM) plus enzalutamide (1 or 10 µM)for 16 hours for RNA extraction and hybridization. Each condition was done in triplicate.
Project description:Illumina gene array analyses of prostate cancer cell lines that had acquired resistance to Enzalutamide (MDV3100). Overall design: mRNA analyses of four cell lines (CWR-R1, LAPC-4, LNCaP, and VCAP) cells that were either untreated, treated for 48hrs with Enz (short-term), or continuously grown in Enzalutamide for >6 months.
Project description:We compare the performance of two library preparation protocols (poly(A) and exome capture) in in vitro degraded RNA samples VcaP cell were grown, and treated with MDV3100 (enzalutamide) or DHT (dihydrotestosterone), intact RNA was isolated and samples were prepared in technical triplicates using two library preparation protocol. Also cells were subject to in vitro degradation through incubation of the whole cell lysate in 37C for increasing amounts of time. Following incbation paired capture and poly(A) libraries were prepared.
Project description:Genetically engineered LNCaPs overexpressing various AR alleles were treated with 0.1% DMSO or 10uM MDV3100 for 24h prior to collection This experiment is designed to see if expressing the F876L/T877A mutant AR can rescue AR signaling in the presence of MDV3100 Engineered lines were seeded in 6-well plates for 3d with 100ng/ml doxycycline prior to treatment with 0.1% DMSO or 10uM MDV3100 for 24h
Project description:Analysis of enzalutamide- and/or olaparib-responsive gene expression in prostate cancer cells. The hypothesis tested in the present study was that enzalutamide influences the expression of genes that are involved in important bioprocesses in prostate cance rcells, including DNA damage response genes and this effect may synergize with poly(ADP-ribose) polymerase inhibitor olaparib in cytotoxicity to prstate cancer cells. prostate cancer cells were pretreated with enzalutamide or vehicle control DMSO for 24 h, followed by treatment with enzalutamide, olaparib, enzalutamide+olaparib, or vehicle control DMSO for 48 h. Gene expression in enzalutamide+olaparib-treated cells was compared with taht in vehicle control- and single agent-treated cells.
Project description:Men who develop metastatic castration-resistant prostate cancer (CRPC) invariably succumb to the disease. The development and progression to CRPC following androgen ablation therapy is predominantly driven by unregulated androgen receptor (AR) signaling1-3. Despite the success of recently approved therapies targeting AR signaling such as abiraterone4-6 and second generation anti-androgens MDV3100 (enzalutamide)7,8, durable responses are limited, presumably due to acquired resistance. Recently JQ1 and I-BET, two selective small molecule inhibitors that target the amino-terminal bromodomains of BRD4, have been shown to exhibit antiproliferative effects in a range of malignancies9-12. Here we show that AR signaling-competent CRPC cell lines are preferentially sensitive to BET bromodomain inhibition. BRD4 physically interacts with the N-terminal domain of AR and can be disrupted by JQ111,13. Like the direct AR antagonist, MDV3100, JQ1 disrupted AR recruitment to target gene loci. In contrast to MDV3100, JQ1 functions downstream of AR, and more potently abrogated BRD4 localization to AR target loci and AR mediated gene transcription including induction of TMPRSS2-ERG and its oncogenic activity. In vivo, BET bromodomain inhibition was more efficacious than direct AR antagonism in CRPC xenograft models. Taken together, these studies provide a novel epigenetic approach for the concerted blockade of oncogenic drivers in advanced prostate cancer. Examination of AR, BRD2, BRD3, BRD4, ERG, RNA Pol II and H3K27ac in prostate cancer cells with respect to BET inhibitors
Project description:Prostate cancer C4-2B cells were cultured in enzalutamide in a dose-escalation manner. After sixty passages cells were resistant to enzalutamide, with a specific sets of genes been deregulated. We performed global gene expression analysis by cDNA microarrays to identify genes responsible for enzalutamide resistance in C4-2B-MDVR cells. Enzalutamide resistant C4-2B-MDVR cells were selected from C4-2B cells during long time enzalutamide treatment. Genes responsible for enzalutamide resistance were identified using C4-2B vs. C4-2B-MDVR RNA extraction and hybridization on Affymetrix microarrays.
Project description:This study examined the gene expression effects of treating androgen-deprived C4-2 prostate cancer cells with the ACLY inhibitor BMS-303141 and the AR antagonist enzalutamide. Overall design: Cells were treated with vehicle control, ACLY inhibitor alone, Enzalutamide alone, and ACLY-inhibitor and Enzalutamide combined together for 24 hours under androgen-depleted conditions (RPMI + 5% charcoal stripped serum). Biological triplicate samples were prepared.
Project description:Effect of castration, bicalutamide, and enzalutamide on androgen receptor binding in Hi-Myc mouse prostate tumors Overall design: Androgen receptor ChIP-seq was performed on Hi-Myc mice tumors 3 days after surgical castration or treatment with bicalutamide or enzalutamide