유방암 세포주(T47D와 MDA-MB231)에서 Genistein의 세포주기 G2/M 정지 기전

Purpose: To analyze the effect of the growth control on human breast cancer cells with genistein treatment and to investigate the mechanism of genistein-induced G2/M arrest in T47D and MDA-MB231 breast carcinoma cells by Cdc25C expression. Methods: We analysed the proliferartion of the two cell lines by using MTT proliferation assay, flow cytometric analysis, real-time quantitative RT-PCR and western blotting and investigated the effect of genistein on cell survival, cellular toxicity, cell cycle progression-related genes and their mRNA and protein alterations. Results: The DNA flow cytometric analysis of both cell lines treated with genistein showed a dose-dependent growth inhibition and accumulation in the G2/M phase of cell cycle. The expression of p21 mRNA and protein increased in both cell lines following genistein treatment but p27 expression was unchanged. Furthermore,decreased Cdc25C expression with decreased polo-like kinase (PLK) 1 expression and increased PLK3 expression were observed after genistein treatment. The decreased level of Cdc25C in the nucleus was associated with decreased phosphorylation of Cdc25C by PLK1. The expression of PLK3was increased with a dose-dependent and a time-dependent manner and was associated with decreased Cdc25C expression. Check point kinase (CHK) 1 and CHK2 revealed different expression patterns each other. The CHK1 expression was independent of the presence of genestein. CHK2 expression increased in MDA-MB231 cells associated with decreased Cdc25C expression but not in T47D. Conclusion: These results suggest that genistein induces a G2/M arrest in human breast cancer cells, the mechanism of which is due, in part, to decreased in Cdc25C phosphatase by a regulatory effect of PLK1, PLK3, and CHK2 as well as increased expression of the cyclin dependent kinase inhibitor p21(WAF1/CIP1).