TY - JOUR T1 - Aromatase Expression in Leptin-Pretreated Human Breast Pre-adipocytes is Enhanced by Zeranol and Suppressed by (−)-Gossypol JF - Anticancer Research JO - Anticancer Res SP - 5077 LP - 5084 VL - 30 IS - 12 AU - SAIYI ZHONG AU - WEI-PING YE AU - PING-PING XU AU - ERIC FENG AU - HONG LI AU - SHU-HONG LIN AU - JIE-YU LIU AU - CHANGWEI MA AU - YOUNG C. LIN Y1 - 2010/12/01 UR - http://ar.iiarjournals.org/content/30/12/5077.abstract N2 - Background: Obesity is associated with an increased risk of estrogen-dependent breast cancer. Recently, concerns have been raised regarding the role of zeranol (Z), a non-steroidal anabolic growth promoter with potent estrogenic activity widely used in the U.S.A. beef industry, as a possible contributor to an increased incidence of human breast cancer. This study hypothesized that obese individuals may be at greater risk of developing zeranol-induced breast cancer. Materials and Methods: The aromatase mRNA expression level of three cell types isolated from adipose tissues were assayed by RT-PCR, and the cell proliferation of primary cultured human normal breast pre-adipocytes (HNBPADs) was investigated using the CellTiter96® non-radioactive method. The effects of Z and gossypol on aromatase expression of leptin-pretreated HNBPADs were evaluated by RT-PCR. Results: HNBPADs expressed higher aromatase than primary cultured human breast epithelial cells and stromal cells. Z enhanced the mitogenic activity of leptin and increased aromatase expression in HNBPADs. Moreover, (−)-gossypol counteracted Z- and leptin-induced cell proliferation and aromatase expression. Conclusion: These results suggested that bioactive Z metabolites contained in meat produced from Z-implanted beef cattle may increase estrogen biosynthesis in obese individuals by increasing aromatase expression and estrogen production, which will promote cell sensitivity and increase breast cancer cell growth. ER -