Critical role of cyclin B1/Cdc2 up-regulation in the induction of mitotic prometaphase arrest in human breast cancer cells treated with 2-methoxyestradiol

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• 作者：Hye Joung Choi ; Bao Ting Zhu
• 关键词：2ME2 ; 2-methoxyestradiol ; MTT ; 3-(4 ; 5-dimethylthiazol-2-yl)-2 ; 5-diphenyltetrazolium bromide ; Rosc ; roscovitine ; CHX ; cycloheximide ; Cdc2 ; cell division control 2 ; Cdk ; cyclin-dependent kinase ; MAD2 ; mitotic arrest deficient 2
• 刊名：Biochimica et Biophysica Acta (BBA)/Molecular Cell Research
• 出版年：2012
• 出版时间：August, 2012
• 年：2012
• 卷：1823
• 期：8
• 页码：1306-1315
• 全文大小：1362 K

文摘

Earlier studies showed that 2-methoxyestradiol (2ME₂), an endogenous nonpolar metabolite of estradiol-17¦Â, is a strong inducer of G₂/M cell cycle arrest (based on analysis of cellular DNA content) in human cancer cell lines. The present study sought to investigate the molecular mechanism underlying 2ME₂-induced cell cycle arrest. We found that 2ME₂ can selectively induce mitotic prometaphase arrest, but not G₂ phase arrest, in cultured MDA-MB-435s and MCF-7 human breast cancer cells. During the induction of prometaphase arrest, there is a time-dependent initial up-regulation of cyclin B1 and Cdc2 proteins, occurring around 12-24 h. The strong initial up-regulation of cyclin B1 and Cdc2 matches in timing the 2ME₂-induced prometaphase arrest. The 2ME₂-induced prometaphase arrest is abrogated by selective knockdown of cyclin B1 and Cdc2, or by pre-treatment of cells with roscovitine, an inhibitor of cyclin-dependent kinases, or by co-treatment of cells with cycloheximide, a protein synthesis inhibitor that was found to suppress the early up-regulation of cyclin B1 and Cdc2. In addition, we provided evidence showing that MAD2 and JNK1 are important upstream mediators of 2ME₂-induced up-regulation of cyclin B1 and Cdc2 as well as the subsequent induction of mitotic prometaphase arrest. In conclusion, treatment of human cancer cells with 2ME₂ causes up-regulation of cyclin B1 and Cdc2, which then mediate the induction of mitotic prometaphase arrest.