植物雌激素對細胞增生、細胞週期進行和雌激素受器Alpha 的綜合效應   全文下載

The Combination Effects of Phytoestrogens on Cell Proliferation, Cell Cycle Progression and Estrogen Receptor Alpha

植物中含有多種植物雌激素（phytoestrogens），這群化合物被發現和人類雌激素（estrogen）相關的癌症如乳癌等之罹患率有關聯性。本研究的主旨為檢測和比較當植物雌激素單獨存在時和數種同時存在時，對人類乳癌細胞株MCF-7的影響是否相同，並探討植物雌激素對人類乳癌細胞生長影響的可能作用機轉。實驗結果顯示植物雌激素biochanin A 和daidzein 皆具有抑制乳癌細胞生長的能力，且當以此兩種植物雌激素共同處理乳癌細胞時，細胞生長則更被抑制。植物雌激素亦被發現能導致細胞週期進行的遲滯，特別是延緩G2/M時期到G1時期的速度，並能降低乳癌細胞中雌激素受器-alpha（estrogen receptor-alpha）mRNA的量，而植物雌激素對乳癌細胞所產生的這些作用，皆無法被雌激素拮抗劑（antiestrogen）所抵銷。因此這些實驗結果顯示植物雌激素對人類乳癌細胞生長的影響和調控細胞週期的進行有關，且可能是透過非典型的雌激素受器-alpha 訊息傳導途徑來進行。

Phytoestrogens are plant chemicals that have been related to the occurrence of human breast cancers and other estrogen-dependent cancers. This study was designed to examine the potential combinational effects and estrogenic activity of phytoestrogens in MCF-7 human breast cancer cells. Results showed that the phytoestrogens biochanin A and daidzein inhibited the proliferation of MCF-7 cells in a dose-dependent manner. Both biochanin A and daidzein delayed the progression of the cell cycle from the G2/M phase to the G1 phase at growth inhibitory concentrations. Treatment with biochanin A down-regulated the level of estrogen receptor-alpha (ER-α) mRNA, but this down-regulation was not affected by the presence of the antiestrogen ICI182,780. When cells were treated with biochanin A at a growth inhibitory concentration of 40 μg/mL, co-administration of daidzein resulted in an enhanced inhibitory effect on the MCF-7 cell growth. In addition, neither the growth inhibition, nor the delayed cell cycle progression induced by biochanin A was affected by the addition of antiestrogen. These results suggest that the growth regulatory effects of phytoestrogens may be associated with cell cycle progression, and the underlying mechanism involves at least in part the modulation of a non-classical ER-α signal pathway.