Shen J C, Klein R D, Wei Q, Guan Y, Contois J H, Wang T T, Chang S, Hursting S D
Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA.
Mol Carcinog. 2000 Oct;29(2):92-102. doi: 10.1002/1098-2744(200010)29:2<92::aid-mc6>3.0.co;2-q.
Genistein, a naturally occurring isoflavone found chiefly in soy products, reportedly has antiprostate cancer effects, but the mechanisms underlying these effects are unknown. We studied the antiproliferative and apoptosis-inducing effects of genistein in the androgen-sensitive human prostate cancer cell line LNCaP. Viable cell number was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay; cell-cycle progression and apoptosis were evaluated by flow cytometry; apoptosis was also assessed by a histone enzyme-linked immunosorbent assay; and the expression of several cell-cycle- and apoptosis-related genes and their gene products was determined by northern blot analysis, western blot analysis, and/or assays based on polymerase chain reaction. Physiologic concentrations of genistein (< or = 20 microM) decreased LNCaP viable cell number in a dose-dependent manner, induced a G(1) cell-cycle block, decreased prostate-specific antigen mRNA expression, and increased p27(KIP1) and p21(WAF1) (mRNA and protein) but had no effect on apoptosis or the mRNA expression of the apoptosis- and cell-cycle-related markers bcl-2, bax, Rb, and proliferating cell nuclear antigen. Higher concentrations of genistein (> 20 microM) did induce apoptosis. We conclude that genistein (at physiologic concentrations) exerts potent antiproliferative effects on LNCaP cells by inducing a G(1) cell-cycle block. The antiproliferative effects of genistein may be mediated by increased levels of p27(KIP1) and p21(WAF1), which are negative cell-cycle regulators that act as cyclin-dependent kinase inhibitors and that have been recently linked with prostate carcinogenesis. These findings may provide insights into the mechanisms underlying the apparent antiprostate cancer effects of soy consumption observed in epidemiologic studies.
染料木黄酮是一种主要存在于豆制品中的天然异黄酮，据报道具有抗前列腺癌作用，但其作用机制尚不清楚。我们研究了染料木黄酮对雄激素敏感的人前列腺癌细胞系LNCaP的抗增殖和诱导凋亡作用。通过3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐法评估活细胞数量；通过流式细胞术评估细胞周期进程和凋亡；还通过组蛋白酶联免疫吸附测定评估凋亡；并通过Northern印迹分析、Western印迹分析和/或基于聚合酶链反应的测定来确定几种细胞周期和凋亡相关基因及其基因产物的表达。生理浓度的染料木黄酮（≤20μM）以剂量依赖性方式降低LNCaP活细胞数量，诱导G1期细胞周期阻滞，降低前列腺特异性抗原mRNA表达，并增加p27(KIP1)和p21(WAF1)（mRNA和蛋白质），但对凋亡或凋亡和细胞周期相关标志物bcl-2、bax、Rb和增殖细胞核抗原的mRNA表达没有影响。更高浓度的染料木黄酮（>20μM）确实诱导了凋亡。我们得出结论，染料木黄酮（在生理浓度下）通过诱导G1期细胞周期阻滞对LNCaP细胞发挥强大的抗增殖作用。染料木黄酮的抗增殖作用可能由p27(KIP1)和p21(WAF1)水平升高介导，它们是负性细胞周期调节因子，作为细胞周期蛋白依赖性激酶抑制剂起作用，并且最近与前列腺癌发生有关。这些发现可能为流行病学研究中观察到的大豆消费明显的抗前列腺癌作用的潜在机制提供见解。
