A Novel Synthetic Androgen Receptor Antagonist

Summary

Principal Investigator: Zhongyun Dong
Affiliation: University of Cincinnati
Country: USA
Abstract: DESCRIPTION (provided by applicant): Current hormonal ablation therapy, the mainstay treatment for advance prostate cancer, is palliative, due the development of androgen-independent growth. Androgen receptor (AR) is expressed in most prostate cancer cells and AR overexpression of AR is sufficient and necessary for androgen-independent growth, which provides strong rationale for developing novel therapies against advanced prostate cancer through downregulation of AR. Dr. Dong's laboratory has identified a novel synthetic compound 6-amino-2-[2-(4-tert- butyl-pnenoxy)-ethylsulfanyl]-1H-pyrimidin-4-one, named DL3 for simplicity, as a potent AR antagonist. DL3 inhibits dihydrotestosterone (DHT)-stimulated cell growth and gene expression in all prostate cancer cell lines tested, including androgen-independent cells and cells resistant to antiandrogens, flutamide (Flut) or nilutamide (Nilut). The inhibitory effects of DL3 are more potent than bicalutamide (Bical), Flut, and Nilut. It inhibits neither AR nuclear localization nor DHT-induced AR NH2-terminus and COOH-terminus interaction and has no detectable AR agonist activity. DL3 reduces AR stability and downregulates of AR protein expression. It competes with DHT but not estradiol for the binding to cells. Docking analysis using protein crystal structure of AR ligand-binding domain (LBD) implies that DL3 can bind to the LBD. These observations prompted Dr. Dong to hypothesize that DL3 is a novel AR antagonist that binds to AR and induces the formation of inactive AR transcription machinery and AR degradation, and, hence, interrupts AR signaling. Three specific aims are proposed to test the hypothesis and to investigate efficacy of DL3 therapy against human prostate cancer cells in animals. In the specific aim 1, he will characterize the binding of DL3 to AR and identify amino acid residues of the DL3 binding site. He will determine the biochemical properties of the binding, investigate whether DL3 competes with DHT for AR binding, and identify amino acid residues of AR that interact with DL3. In the specific aim 2, he will investigate effects of DL3 on proteosome-mediated degradation of AR and assembly of AR transcription complex. He will determine effects of DL3 and Bical on AR stability, ubiquitination, and association with E3 ubiquitin ligase. By using the chromatin immunoprecipitation (ChIP) assay, he will investigate whether treatment with DL3 and Bical induce formation of transcription-inactive AR complex at the promoter region of prostate-specific antigen gene and identify cofactors in the complex. In the specific aim 3, Dr. Dong propose to investigate therapeutic effects of DL3 against human prostate cancer cells in mice. He will determine and compare effects of DL3 and Bical, alone or in combination with castration, on growth of tumors formed by both androgen-dependent and -independent cells and by cells refractory to Flut. He will determine DL3 distribution in tumor-bearing mice and correlate therapeutic effects with expression of AR and AR-target genes in tumors. These studies will firmly establish that DL3 is a novel AR antagonist and will enrich the understanding of mechanisms by which Bical interrupts AR signaling. Project Narrative Our preliminary studies have identified a novel synthetic compound 6-amino-2-[2-(4-tert- butyl-pnenoxy)-ethylsulfanyl]-1H-pyrimidin-4-one, named DL3 for simplicity. DL3 competitively inhibits the binding of DHT to human prostate cancer cells, but not estradiol to human breast cancer cells. It downregulates androgen receptor expression and suppresses androgen-induced cell growth and gene expression in prostate cancer cells. The proposed research will establish that DL3 is a novel AR antagonist, will elucidate mechanisms by which DL3 interrupts AR signaling, and will determine therapeutic effects of DL3 against human prostate cancer cells in mice. PUBLIC HEALTH RELEVANCE: Our preliminary studies have identified a novel synthetic compound 6-amino-2-[2-(4-tertbutyl-pnenoxy)-ethylsulfanyl]-1H-pyrimidin-4-one, named DL3 for simplicity. DL3 competitively inhibits the binding of DHT to human prostate cancer cells, but not estradiol to human breast cancer cells. It downregulates androgen receptor expression and suppresses androgen-induced cell growth and gene expression in prostate cancer cells. The proposed research will establish that DL3 is a novel AR antagonist, will elucidate mechanisms by which DL3 interrupts AR signaling, and will determine therapeutic effects of DL3 against human prostate cancer cells in mice.
Funding Period: ----------------2008 - ---------------2013-
more information: NIH RePORT

Top Publications

  1. pmc Hemostatic gelatin sponge is a superior matrix to matrigel for establishment of LNCaP human prostate cancer in nude mice
    Lingling Cui
    Division of Hematology Oncology, University of Cincinnati Cancer Institute, Cincinnati, Ohio, USA
    Prostate 72:1669-77. 2012
  2. pmc Regulation of heat shock protein 70-1 expression by androgen receptor and its signaling in human prostate cancer cells
    Shan Lu
    Department of Internal Medicine, The University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
    Int J Oncol 36:459-67. 2010
  3. pmc Preferential induction of G1 arrest in androgen-responsive human prostate cancer cells by androgen receptor signaling antagonists DL3 and antiandrogen bicalutamide
    Shan Lu
    Department of Internal Medicine, The University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
    Cancer Lett 298:250-7. 2010
  4. pmc Secretory phospholipase A2-IIa is involved in prostate cancer progression and may potentially serve as a biomarker for prostate cancer
    Zhongyun Dong
    Department of Medicine, University of Cincinnati College of Medicine, 2120 East Galbraith Road, Cincinnati, OH 45237 0507, USA
    Carcinogenesis 31:1948-55. 2010
  5. pmc Secretory phospholipase A2-IIa is a target gene of the HER/HER2-elicited pathway and a potential plasma biomarker for poor prognosis of prostate cancer
    Leslie Oleksowicz
    Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
    Prostate 72:1140-9. 2012
  6. pmc Plasma secretory phospholipase A2-IIa as a potential biomarker for lung cancer in patients with solitary pulmonary nodules
    Elena Kupert
    Department of Cancer and Cell Biology, University of Cincinnati College of Medicine, UC Metabolic Diseases Institute, 2120 E, Galbraith Road, Building A, Room 259, Cincinnati, OH 45237 0507, USA
    BMC Cancer 11:513. 2011
  7. pmc Small-molecule targeting of proliferating cell nuclear antigen chromatin association inhibits tumor cell growth
    Zongqing Tan
    Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
    Mol Pharmacol 81:811-9. 2012

Scientific Experts

  • Elena Kupert
  • Zhongyun Dong
  • Shan Lu
  • Zongqing Tan
  • Leslie Oleksowicz
  • Lingling Cui
  • Linda Levin
  • R Bruce Bracken
  • Barbara Burke
  • Matthew Wortman
  • Krishnanath Gaitonde
  • Yin Liu
  • Zongqin Tan
  • Shanna J Smith
  • Wenjie Li
  • Pingping Chen
  • William L Seibel
  • CHRIS R EVELYN
  • Yi Zheng
  • Linda H Malkas
  • Paul Succop
  • Kelsey L Dillehay
  • Kieran F Scott
  • Qihui Jim Zhai
  • Matt Wortman
  • Jiang Wang

Detail Information

Publications7

  1. pmc Hemostatic gelatin sponge is a superior matrix to matrigel for establishment of LNCaP human prostate cancer in nude mice
    Lingling Cui
    Division of Hematology Oncology, University of Cincinnati Cancer Institute, Cincinnati, Ohio, USA
    Prostate 72:1669-77. 2012
    ..However, tumors formed by a mixture of tumor cells and Matrigel may vary significantly. The purpose of this study was to compare tumor development and growth of LNCaP human prostate cancer cells mixed with Matrigel or in gelatin sponges...
  2. pmc Regulation of heat shock protein 70-1 expression by androgen receptor and its signaling in human prostate cancer cells
    Shan Lu
    Department of Internal Medicine, The University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
    Int J Oncol 36:459-67. 2010
    ..These data suggest that AR and its signaling regulate hsp70-1 expression in prostate cancer cells and that HSPA1B could be an AR target gene...
  3. pmc Preferential induction of G1 arrest in androgen-responsive human prostate cancer cells by androgen receptor signaling antagonists DL3 and antiandrogen bicalutamide
    Shan Lu
    Department of Internal Medicine, The University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
    Cancer Lett 298:250-7. 2010
    ..The data indicated that DL3 inhibit cell growth in both AR-dependent and -independent manners and is potentially a potent therapeutic agent for the management of advanced human prostate cancer...
  4. pmc Secretory phospholipase A2-IIa is involved in prostate cancer progression and may potentially serve as a biomarker for prostate cancer
    Zhongyun Dong
    Department of Medicine, University of Cincinnati College of Medicine, 2120 East Galbraith Road, Cincinnati, OH 45237 0507, USA
    Carcinogenesis 31:1948-55. 2010
    ..Given that sPLA2-IIa overexpression is associated with prostate development and progression, serum sPLA2-IIa may serve as a prognostic biomarker for prostate cancer and a potential surrogate prostate biomarker indicative of tumor burden...
  5. pmc Secretory phospholipase A2-IIa is a target gene of the HER/HER2-elicited pathway and a potential plasma biomarker for poor prognosis of prostate cancer
    Leslie Oleksowicz
    Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
    Prostate 72:1140-9. 2012
    ..The current study further explored the underlying mechanism of sPLA2-IIa overexpression and the potential role of sPLA2-IIa as a prostate cancer biomarker...
  6. pmc Plasma secretory phospholipase A2-IIa as a potential biomarker for lung cancer in patients with solitary pulmonary nodules
    Elena Kupert
    Department of Cancer and Cell Biology, University of Cincinnati College of Medicine, UC Metabolic Diseases Institute, 2120 E, Galbraith Road, Building A, Room 259, Cincinnati, OH 45237 0507, USA
    BMC Cancer 11:513. 2011
    ..Currently, there is no convenient and reliable biomarker effective for early diagnosis. Secretory phospholipase A2-IIa (sPLA2-IIa) is secreted into the circulation by cancer cells and may allow for an early detection of lung cancer...
  7. pmc Small-molecule targeting of proliferating cell nuclear antigen chromatin association inhibits tumor cell growth
    Zongqing Tan
    Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
    Mol Pharmacol 81:811-9. 2012
    ..They are valuable tools in studying PCNA function and may be useful for future PCNA-targeted cancer therapy...