CRCU

Chemical Research in Chinese Universities ›› 2013, Vol. 29 ›› Issue (5): 911-916.doi: 10.1007/s40242-013-3123-6

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Phytoestrogens Inhibiting Androgen Receptor Signal and Prostate Cancer Cell Proliferation

WU Jing1, LIU Shu1, SHEN Xiao-yan1, YANG Nan-yang1, LIU Ying2, TSUJI Ichiro3, YAMAMURA Takaki4, LI Jiang2, LI Xiao-meng1   

  1. 1. Key Laboratory of Molecular Epigenetics, Ministry of Education, Institute of Genetics and Cytology, Northeast Normal University, Changchun 130024, P. R. China;
    2. Dental Hospital, Jilin University, Changchun 130021, P. R. China;
    3. Department of Public Health, Tohoku University, Sendai 980-8576, Japan;
    4. Department of Nutritional Sciences, Morioka University, Morioka 020-0183, Japan
  • Received:2013-03-18 Revised:2013-06-05 Online:2013-10-01 Published:2013-09-17
  • Contact: LI Xiao-meng, LI Jiang E-mail:lixm441@nenu.edu.cn;ljiang@jlu.edu.cn
  • Supported by:

    Supported by the Project of the Ministry of Science and Technology of China(No.2010DFA31430), the Project of the Ministry of Education of China(Nos.NCET-10-0316, 10SSXT147), the Project of the Jilin Provincial Science & Technology Department, China(Nos.20070719, 200905116) and the Project of the Changchun Science & Technology Department, China (No.2011114-11GH29).

Cited

9

Abstract:

The androgen receptor(AR) signaling activated by dihydrotestosterone(DHT) plays critical roles in prostate cancer development and progression. Phytoestrogens, which are diphenolic compounds with estrogen and anti-estrogen effects, can bind to estrogen receptors. However, their function on AR signaling has not been fully elucidated. In this study, dual-luciferase reporter assay, immunobloting, docking system test, MTT assay, immunofluorescence and chromatin immunoprecipitation(ChIP) assays were employed to examine the potential effects of three phytoestrogens(genistein, daidzein, flavone) on DHT-activated prostate specific antigen(PSA) activation, cell proliferation and AR transactivation in lymph node carcinoma of prostate(LNCaP) cells. Phytoestrogens were detected to down-regulate DHT-activated AR-mediated PSA promoter transactivation by dual-luciferase reporter system. Furthermore, three phytoestrogens, especially genistein, were demonstrated to significantly decrease AR-activated PSA protein expression by Western blotting analysis. MTT experiment proves that phytoestrogens, especially genistein, remarkably inhibits the DHT-induced cell proliferation in LNCaP cells. To provide reasonable explanations for experimental phenomena mentioned above, we did docking system test and detected phytoestrogens to share the same AR-binding site with DHT. To further prove the competition between phytoestrogen and DHT on AR binding, we examined the effects of phytoestrogens on DHT-activated AR nuclear translocation and immunofluorescence analysis which confirms that phytoestrogens, especially genistein, inhibit DHT-activated androgen receptor nuclear translocation. Results from ChIP show that phytoestrogens down-regulate DHT-induces AR binding to the androgen response elements(AREs, including AREI, AREII, and AREIII) in PSA promoter. Genistein remarkably down-regulates AR, binding to the AREI located in -250― -39 bp and AREIII in -4170― -3978 bp in the presence of DHT. In general, three phytoestrogens were identified to inhibit DHT-AR binding by competitively binding to AR and inhibit AR-mediated transactivation. And genistein shows the strongest effects among three phytoestrogens. Our findings confirm that phytoestrogens are AR antagonist in the regulation of AR-related PSA activation and cell proliferation, which provides valuable insights into the treatment of prostate cancer.

Key words: Androgen receptor, Phytoestrogen, Prostate specific antigen(PSA), Prostate cancer