Combined inhibitory effects of soy isoflavones and curcumin on the production of prostate-specific antigen

• Published in: The Prostate 2010-07, Vol.70 (10), p.1127-1133
• Main Authors: Ide, Hisamitsu, Tokiwa, Shino, Sakamaki, Kentaro, Nishio, Koujiro, Isotani, Shuji, Muto, Satoru, Hama, Takanori, Masuda, Hiroko, Horie, Shigeo
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Anti-Inflammatory Agents, Non-Steroidal - pharmacology; Antineoplastic Combined Chemotherapy Protocols - administration & dosage; Biological and medical sciences; Blotting, Western; Cell Line, Tumor; curcumin; Curcumin - administration & dosage; Curcumin - pharmacology; Double-Blind Method; Gynecology. Andrology. Obstetrics; Humans; isoflavones; Isoflavones - administration & dosage; Isoflavones - pharmacology; Male; Male genital diseases; Medical sciences; Middle Aged; Nephrology. Urinary tract diseases; prostate cancer; Prostate-Specific Antigen - antagonists & inhibitors; Prostate-Specific Antigen - biosynthesis; Prostate-Specific Antigen - blood; Prostatic Neoplasms - blood; Prostatic Neoplasms - drug therapy; Prostatic Neoplasms - metabolism; PSA; Receptors, Androgen - biosynthesis; Receptors, Androgen - blood; Tumors; Tumors of the urinary system; Urinary tract. Prostate gland
• ISSN: 0270-4137; 1097-0045
• DOI: 10.1002/pros.21147

BACKGROUND Sustained chronic inflammation in the prostate promotes prostate carcinogenesis. Since an elevated level of prostate‐specific antigen (PSA) per se reflects the presence of inflammation in the prostate, intervention to improve the PSA value might potentially have beneficial effects for the prevention of the development of prostate cancer. Isoflavones and curcumin have anti‐inflammatory and anti‐oxidant properties. We examined the biological effects of soy isoflavones and curcumin on LNCaP cells. After that, we conducted a clinical trial for men who received prostate biopsies, but were not found to have prostate cancer, to evaluate the effects of soy isoflavones and curcumin on serum PSA levels. METHODS The expression of androgen receptor and PSA were examined in LNCaP cells before and after treatment of isoflavones and/or curcumin. Eighty‐five participants were randomized to take a supplement containing isoflavones and curcumin or placebo daily in a double‐blind study. Subjects were subdivided by the cut‐off of their baseline PSA value at 10 µg/ml. We evaluated values of PSA before and 6 months after treatment. RESULTS The production of PSA were markedly decreased by the combined treatment of isoflavones and curcumin in prostate cancer cell line, LNCaP. The expression of the androgen receptor was also suppressed by the treatment. In clinical trials, PSA levels decreased in the patients group with PSA ≥ 10 treated with supplement containing isoflavones and curcumin (P = 0.01). CONCLUSIONS Our results indicated that isoflavones and curcumin could modulate serum PSA levels. Curcumin presumably synergizes with isoflavones to suppress PSA production in prostate cells through the anti‐androgen effects. Prostate 70: 1127–1133, 2010. © 2010 Wiley‐Liss, Inc.