Prostate cancer (PCa) has major impacts on veterans'health care and its incidence will continue to grow as the population ages. Despite continual progress in the development of PCa therapies, patients with androgen-deprivation-therapy (ADT)-resistant disease have limited options. Perenteral estrogens with reduced cardiovascular toxicities have shown promise in PCa treatment in recent years. An orphan G protein-coupled receptor (GPR30) with high-affinity and low-capacity binding to estrogens was identified at both the plasma membrane and the endoplasmic reticulum. This receptor is believed to be the key mediator of the non-genomic action of estrogens. Upon its binding to ligand, GPR30 either stimulates or inhibits cell proliferation in an ER- independent, cell type-specific manner. The identificaion of G-1 (1-[4-(6-bromobenzo[1,3]dioxol-5yl)-3a,4,5,9b- tetrahydro-3H-cyclopenta[c]quinolin-8-yl]-ethanone) as a GPR30-selective agonist with no estrogenic activity provides a unique opportunity to elucidate the biological significance of GPR30 in cell growth regulation, especially in cells that express ER1 and/or ER2. Using G-1, and confirmed by siRNA knockdown experiments, we recently demonstrated strong inhibitory effects of G-1 on the growth of AD and ADT-resistant PCa cells in culture. It also inhibited PC-3 xenograft growth in nude mice. A trend of reduction of GPR30 mRNA expression was observed in PCa clinical specimens when compared to their adjacent normal tissues although the degree of expression varies a great deal among PCa specimens. Treatment of PCa cells with 5-aza-2'-deoxycytidine, a demethylating agent, tricostatinA, a HDACi, or an ADT increased GPR30 expression. Based on these novel findings, we here hypothesize that activation of GPR30 signaling via its specific ligand G-1, either alone or in combination with a demethylating agent, a histone deacetylase inhibitor (HDACi), or androgen ablation, is an effective anti-PCa therapy, and that GPR30 has prognostic value in PCa.
Three aims are proposed to test this hypothesis. Objective 1: Establish the role of GPR30 in G-1-induced growth inhibition/cell kill in AD and ADT- resistant PCa cells under in vitro and in vivo settings. Objective 2: Determine whether DNA methylation, histone deacetylation, or androgen repression are involved in the regulation of GPR30 expression and compare the efficacies of G-1, alone or in combination with one of these agents in curbing PCa growth. Objective 3: Evaluate the prognostic value of GPR30 expression in PCa. This project will provide the first evidence in support of GPR-30 as a novel PCa therapeutic target and lay down a foundation for future development of GPR30-based therapies for PCa.

Public Health Relevance

Prostate cancer affects one out of six men in their life time and has significant impacts on veterans'health care. The main thrust of this research is to design a new class of prostate cancer therapies based on our understanding of a G-coupled protein receptor known as GPR30. The research is relevant to the treatment of early stage and advanced stage prostate cancer and may establish GPR30 as a prognostic marker for prostate cancer.

Agency
National Institute of Health (NIH)
Institute
Veterans Affairs (VA)
Type
Non-HHS Research Projects (I01)
Project #
5I01BX000675-03
Application #
8397551
Study Section
Oncology A (ONCA)
Project Start
2011-04-01
Project End
2014-03-31
Budget Start
2013-04-01
Budget End
2014-03-31
Support Year
3
Fiscal Year
2013
Total Cost
Indirect Cost
Name
Cincinnati VA Medical Center Research
Department
Type
DUNS #
827658092
City
Cincinnati
State
OH
Country
United States
Zip Code
45220
Tarapore, Pheruza; Hennessy, Max; Song, Dan et al. (2017) High butter-fat diet and bisphenol A additively impair male rat spermatogenesis. Reprod Toxicol 68:191-199
Ho, Shuk-Mei; Cheong, Ana; Adgent, Margaret A et al. (2017) Environmental factors, epigenetics, and developmental origin of reproductive disorders. Reprod Toxicol 68:85-104
Ho, Shuk-Mei; Rao, Rahul; To, Sarah et al. (2017) Bisphenol A and its analogues disrupt centrosome cycle and microtubule dynamics in prostate cancer. Endocr Relat Cancer 24:83-96
Leung, Yuet-Kin; Govindarajah, Vinothini; Cheong, Ana et al. (2017) Gestational high-fat diet and bisphenol A exposure heightens mammary cancer risk. Endocr Relat Cancer 24:365-378
Tarapore, Pheruza; Hennessy, Max; Song, Dan et al. (2016) Data on spermatogenesis in rat males gestationally exposed to bisphenol A and high fat diets. Data Brief 9:812-817
Miller, Marian; Bailey, Banita; Govindarajah, Vinothini et al. (2016) A community survey on knowledge of the impact of environmental and epigenetic factors on health and disease. Perspect Public Health 136:345-352
Lam, Hung-Ming; Ho, Shuk-Mei; Chen, Jing et al. (2016) Bisphenol A Disrupts HNF4?-Regulated Gene Networks Linking to Prostate Preneoplasia and Immune Disruption in Noble Rats. Endocrinology 157:207-19
Govindarajah, Vinothini; Leung, Yuet-Kin; Ying, Jun et al. (2016) In utero exposure of rats to high-fat diets perturbs gene expression profiles and cancer susceptibility of prepubertal mammary glands. J Nutr Biochem 29:73-82
Martinez, Alan M; Cheong, Ana; Ying, Jun et al. (2015) Effects of High-Butterfat Diet on Embryo Implantation in Female Rats Exposed to Bisphenol A. Biol Reprod 93:147
Ho, Shuk-Mei; Tam, Neville Ngai Chung (2015) Organoid model shows effect of BPA on prostate development. Nat Rev Urol 12:658-9

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