Tonetti Debra A, Zhang Yiyun, Zhao Huiping, Lim Sok-Bee, Constantinou Andreas I
Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA.
Nutr Cancer. 2007;58(2):222-9. doi: 10.1080/01635580701328545.
Soy supplements are often consumed by women for alleviating menopausal symptoms or for the perceived protective effects against breast cancer. More concerning is the concurrent consumption of soy isoflavones with tamoxifen (TAM) for prevention or treatment of breast cancer. We previously described a T47D:A18/protein kinase C (PKC)alpha TAM-resistant tumor model that exhibits autonomous growth and estradiol-induced tumor regression. We compared the estrogenicity of the isoflavones genistein, daidzein, and the daidzein metabolite equol in the parental T47D:A18 and T47D:A18/PKC alpha cell lines in vitro and in vivo. Whereas equol exerts estrogenic effects on T47D:A18 cells in vitro, none of the isoflavones stimulated T47D:A18 tumor growth. T47D:A18/PKC alpha tumor growth was partially stimulated by genistein, yet partially inhibited by daidzein. Interestingly, coadministration of TAM with either daidzein or genistein produced tumors of greater size than with TAM alone. These findings suggest that simultaneous consumption of isoflavone supplements with TAM may not be safe.
女性经常食用大豆补充剂来缓解更年期症状或预防乳腺癌。更令人担忧的是，大豆异黄酮与他莫昔芬（TAM）同时用于预防或治疗乳腺癌。我们之前描述了一种T47D:A18/蛋白激酶C（PKC）α他莫昔芬耐药肿瘤模型，该模型表现出自主生长和雌二醇诱导的肿瘤消退。我们在体外和体内比较了异黄酮染料木黄酮、大豆苷元和大豆苷元代谢产物雌马酚在亲本T47D:A18和T47D:A18/PKCα细胞系中的雌激素活性。虽然雌马酚在体外对T47D:A18细胞有雌激素作用，但这些异黄酮均未刺激T47D:A18肿瘤生长。染料木黄酮部分刺激T47D:A18/PKCα肿瘤生长，而大豆苷元则部分抑制其生长。有趣的是，将TAM与大豆苷元或染料木黄酮共同给药产生的肿瘤比单独使用TAM时更大。这些发现表明，异黄酮补充剂与TAM同时食用可能不安全。
