Carcinogenesis, Vol. 22, No. 9, 1399-1403,
September 2001
© 2001 Oxford University Press
MOLECULAR EPIDEMIOLOGY AND CANCER PREVENTION |
Silymarin inhibits function of the androgen receptor by reducing nuclear localization of the receptor in the human prostate cancer cell line LNCaP
Department of Biochemistry and Molecular Biology and Department of Urology, Mayo Graduate School, Mayo Clinic/Foundation, Rochester, MN 55905, USA
A number of reports have shown that the polyphenolic flavonoid silymarin (SM) is an effective anticancer agent. Agents with novel mechanisms of blocking androgen receptor (AR) function may be useful for prostate cancer prevention and therapy. Previous studies showed that silibinin (SB), the major active component of SM, could inhibit cell proliferation of a human prostate cancer cell line, LNCaP, by arresting the cell cycle at the G1 phase without causing cell death. This study further delineates the potential molecular mechanism by which SM and SB exhibit antiproliferative effects on androgen-responsive prostate cancer cells by inhibiting function of the AR. We observed that SM and SB inhibited androgen-stimulated cell proliferation as well as androgen-stimulated secretion of both prostate-specific antigen (PSA) and human glandular kallikrein (hK2). Additionally, for the first time, we show that an immunophilin, FKBP51, is androgen regulated and that this up-regulation is suppressed by SM and SB. We further demonstrate that transactivation activity of the AR was diminished by SM and SB using gene transfer of PSA promoter and hK2 androgen-responsive element constructs. However, expression and steroid-binding ability of total AR were not affected by SM in western blotting and ligand-binding assays. Intriguingly, we found that nuclear AR levels are significantly reduced by SM and SB in the presence of androgens using western blotting assay and immunocytochemical staining. This study provides a new insight into how SM and SB negatively modulate androgen action in prostate cancer cells.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
M. B. Cox, D. L. Riggs, M. Hessling, F. Schumacher, J. Buchner, and D. F. Smith FK506-Binding Protein 52 Phosphorylation: A Potential Mechanism for Regulating Steroid Hormone Receptor Activity Mol. Endocrinol., December 1, 2007; 21(12): 2956 - 2967. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. N. Syed, N. Khan, F. Afaq, and H. Mukhtar Chemoprevention of Prostate Cancer through Dietary Agents: Progress and Promise Cancer Epidemiol. Biomarkers Prev., November 1, 2007; 16(11): 2193 - 2203. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Periyasamy, M. Warrier, M. P. M. Tillekeratne, W. Shou, and E. R. Sanchez The Immunophilin Ligands Cyclosporin A and FK506 Suppress Prostate Cancer Cell Growth by Androgen Receptor-Dependent and -Independent Mechanisms Endocrinology, October 1, 2007; 148(10): 4716 - 4726. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Deep, N. H. Oberlies, D. J. Kroll, and R. Agarwal Isosilybin B and isosilybin A inhibit growth, induce G1 arrest and cause apoptosis in human prostate cancer LNCaP and 22Rv1 cells Carcinogenesis, July 1, 2007; 28(7): 1533 - 1542. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Deep and R. Agarwal Chemopreventive Efficacy of Silymarin in Skin and Prostate Cancer Integr Cancer Ther, June 1, 2007; 6(2): 130 - 145. [Abstract] [PDF] |
||||
![]() |
W. Yong, Z. Yang, S. Periyasamy, H. Chen, S. Yucel, W. Li, L. Y. Lin, I. M. Wolf, M. J. Cohn, L. S. Baskin, et al. Essential Role for Co-chaperone Fkbp52 but Not Fkbp51 in Androgen Receptor-mediated Signaling and Physiology J. Biol. Chem., February 16, 2007; 282(7): 5026 - 5036. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. P Singh and R. Agarwal Mechanisms of action of novel agents for prostate cancer chemoprevention. Endocr. Relat. Cancer, September 1, 2006; 13(3): 751 - 778. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Zhang, X.-W. Wang, D. Jelovac, T. Nakanishi, M.-h. Yu, D. Akinmade, O. Goloubeva, D. D. Ross, A. Brodie, and A. W. Hamburger The ErbB3-binding protein Ebp1 suppresses androgen receptor-mediated gene transcription and tumorigenesis of prostate cancer cells PNAS, July 12, 2005; 102(28): 9890 - 9895. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. R. Davis-Searles, Y. Nakanishi, N.-C. Kim, T. N. Graf, N. H. Oberlies, M. C. Wani, M. E. Wall, R. Agarwal, and D. J. Kroll Milk Thistle and Prostate Cancer: Differential Effects of Pure Flavonolignans from Silybum marianum on Antiproliferative End Points in Human Prostate Carcinoma Cells Cancer Res., May 15, 2005; 65(10): 4448 - 4457. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Bonham, J. Posakony, I. Coleman, B. Montgomery, J. Simon, and P. S. Nelson Characterization of Chemical Constituents in Scutellaria baicalensis with Antiandrogenic and Growth-Inhibitory Activities toward Prostate Carcinoma Clin. Cancer Res., May 15, 2005; 11(10): 3905 - 3914. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. M. Velasco, K. A. Gillis, Y. Li, E. L. Brown, T. M. Sadler, M. Achilleos, L. M. Greenberger, P. Frost, W. Bai, and Y. Zhang Identification and Validation of Novel Androgen-Regulated Genes in Prostate Cancer Endocrinology, August 1, 2004; 145(8): 3913 - 3924. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Pan, J.-S. Zhang, M. H. Gazi, and C. Y. F. Young The Cyclooxygenase 2-specific Nonsteroidal Anti-inflammatory Drugs Celecoxib and Nimesulide Inhibit Androgen Receptor Activity via Induction of c-Jun in Prostate Cancer Cells Cancer Epidemiol. Biomarkers Prev., August 1, 2003; 12(8): 769 - 774. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. R. Hubler, W. B. Denny, D. L. Valentine, J. Cheung-Flynn, D. F. Smith, and J. G. Scammell The FK506-Binding Immunophilin FKBP51 Is Transcriptionally Regulated by Progestin and Attenuates Progestin Responsiveness Endocrinology, June 1, 2003; 144(6): 2380 - 2387. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. R. Sinars, J. Cheung-Flynn, R. A. Rimerman, J. G. Scammell, D. F. Smith, and J. Clardy Structure of the large FK506-binding protein FKBP51, an Hsp90-binding protein and a component of steroid receptor complexes PNAS, February 4, 2003; 100(3): 868 - 873. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Zhang, J. Ni, E. M. Messing, E. Chang, C.-R. Yang, and S. Yeh Vitamin E succinate inhibits the function of androgen receptor and the expression of prostate-specific antigen in prostate cancer cells PNAS, May 28, 2002; 99(11): 7408 - 7413. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Yanaida, H. Kohno, K. Yoshida, Y. Hirose, Y. Yamada, H. Mori, and T. Tanaka Dietary silymarin suppresses 4-nitroquinoline 1-oxide-induced tongue carcinogenesis in male F344 rats Carcinogenesis, May 1, 2002; 23(5): 787 - 794. [Abstract] [Full Text] [PDF] |
||||









