萝卜硫烷对乳腺癌细胞增殖、细胞周期、细胞凋亡的影响及作用机制研究

目的:研究萝卜硫烷(sulforaphane,SUL)对不同类型乳腺癌细胞增殖和细胞周期细胞凋亡的影响及其作用机制。方法:采用MTT法、流式细胞术和Western印迹法,研究不同浓度受试物对F3Ⅱ、MCF-7、MDA-MB-231和ZR-75-1细胞增殖抑制、细胞周期阻滞、F3Ⅱ细胞凋亡和p34cdc2及Cdc25C表达的影响。结果:(1)SUL对所选的四个细胞系均有很强的增殖抑制作用,其中雌激素正响应型(ERP)细胞对SUL的敏感性明显强于雌激素负响应型(ERN)细胞和扩散性较强的F3Ⅱ细胞;(2)SUL对F3Ⅱ细胞和两种ERP细胞均呈现G2/M期阻滞作用,而对ERN细胞周期则无影响;(3)SUL阻滞F3Ⅱ细胞从G2期向M期转化的作用机制是提高Cdc2的磷酸化水平,降低Cdc25C磷酸化酶的表达,从而抑制细胞周期素B1-Cdc2复合物激酶的去磷酸化作用;(4)在实验条件下,SUL不引起F3Ⅱ细胞凋亡。结论:SUL对四个乳腺癌细胞系细胞增殖抑制活性和细胞周期影响存在明显的差异,不引起F3Ⅱ细胞凋亡。对F3Ⅱ细胞周期G2/M阻滞作用的机制是提高Cdc2的磷酸化水平,降低Cdc25C磷酸化酶的表达。

EFFECT OF SULFORAPHANE ON PROLIFERATION, CELL CYCLE AND APOPTOSIS OF BREAST CANCER CELL LINES AND ITS MECHANISM

Objective: To study the effect of sulforaphane (SUL) on cell growth inhibition, cell cycle, apoptosis and its mechanism in different breast cancer cell lines. Methods: By means of MTT assay, flow cytometry and Western blotting, the effects of the SUL different concentrations on cell growth inhibition, cell cycle arrest, F3Ⅱapoptosis and expression of p34cdc2 and Cdc25C were studied. Results: (1) SUL had strong inhibition effects on the cell growth of tested mammary cancer cell lines, in which the sensitivity of ERP cell lines to SUL was stronger than that of ERN cell line. (2) SUL exhibited obviously G2/M cell cycle arrest to F3Ⅱ and two kinds of ERP cell lines at 5-10μmol/L, whereas no effect on the cell cycle of ERN cell line. (3)The mechanism of hindering transition of F3 Ⅱ cells from G2 phase to M phase was enhancing the phosphorylation of Cdc2, down-regulating the expression of Cdc25C, and inducing inhibition to thedephosphorylation of cyclin B1-Cdc2 complex. (4) No apoptosis was observed under tested conditions. Conclusion: Sulforaphane exhibited obvious differences in the inhibiting effects on the cell proliferation and cell cycle arrests of four different tested breast cancer cell lines, and did not induce apoptosis in F3Ⅱcell line under tested conditions. The mechanism of cell cycle arrest of F3Ⅱcell line appears to involve enhancing the phosphorylation of Cdc2, and down-regulating the expression of Cdc25C.