Mechanisms Of Genistein Induce The Cell Growth Inhibition And Cell Cycle In Breast Cancer Cell Line MDA-MB-435S

Genistein,the major isoflavonoid contained in soybean,is believed to exert a pieiotropic effect including anti-angiogenic,anti-oxidant,and anti-carcinogenic actions.Epidemiological studies,as well as work perfomed on animal models, suggest that it is responsible for a chemopreventive effect on breast,colon,and skin tumors.Genistein potentaily inhibits cell proliferation,and may also induce cell differentiation or apoptosis.lt has been shown to inhibit several tyrosine-specific protein kinases.Specially the study of the apoptosis and cell cycle related genes expression in melanoma cells suggest that genistein can make down-regulation of Bcl-2 and p53 expression and up-regulation of Bax and P21WAFI expression.Even it can make the checkpoint kinase Chk2 activate and restrain the expression of protein Chkl.In recently years,the internal researchers obtained similar results in protein and mRNA levels. However,it remains unknown whether the anti-proliferation effect of genistein is dependent on these inhibitions. The majority researchers prefer to the anti-proliferation effect by genistein is related with two pathways of apoptosis and cell cycle arrest.Above all,in order to go a step of giving new thoughts to molecular mechanisms of anti-proliferation by genistein,we investigated the inhibition of cell growth.cell cycle arrest,the related protein expression and mRNA level study in estrogen receptor-negative breast cancer cell line MDA-MB-435S.Part 1 The Influence of Genistein On The Cell Proliferation and Cell Cycle of MDA-MB-435S cellsIn order to study the influence of proliferation and cell cycle effected of genistein,MTT assay,light microscope,fluorescent microscope and the technique of flow cytometry were performed,the MDA-MB-435S cell line was selected as target cell.The cells were treated with genistein at dose of 0.0,6.25,12.5,25.0,50.0 and 100.0 # mol/L,and the values of OD of MTTwere measured at 2,4,6 days,respectively.It was found that when the exposure dose of genistein was lower than 12.5 # mol/L could slightly promote cell growth,but when the exposure dose was higher than 20 # mol/L,with the increase of exposure time and dose,the cell growth was inhibited more and more stronger.The light microscope showed that the normal cell shaped like shuttle,but when the cells were treated at the dose more than 20 # mol/L,the cell were wrinkled and shrinked,it also seemed more obviously with the increase of the exposure dose.The fluorescent microscope showed that compared with the normal cell there were few typical apoptosis nucleus with the low exposure dose,but at the high dose it added up.The technique of flow cytometry examined the cell cycle showed there are fewer percentage of G2-M arrest with low exposure dose(<12.5 M mol/L) than the normal cell,in contrast when the dose higher than 20 u mol/L,the G2-M arrest more and more obviously with the exposure time and dose increase.Then the mechanism of anti-proliferation effected of genistein may related with apoptosis and /or cell cycle arrest.