Xiao Dong, Herman-Antosiewicz Anna, Antosiewicz Jedrzej, Xiao Hui, Brisson Marni, Lazo John S, Singh Shivendra V
Department of Pharmacology and University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
Oncogene. 2005 Sep 15;24(41):6256-68. doi: 10.1038/sj.onc.1208759.
Molecular mechanism of cell cycle arrest caused by diallyl trisulfide (DATS), a garlic-derived cancer chemopreventive agent, has been investigated using PC-3 and DU 145 human prostate cancer cells as a model. Treatment of PC-3 and DU 145 cells, but not a normal prostate epithelial cell line (PrEC), with growth suppressive concentrations of DATS caused enrichment of the G(2)-M fraction. The DATS-induced cell cycle arrest in PC-3 cells was associated with increased Tyr(15) phosphorylation of cyclin-dependent kinase 1 (Cdk 1) and inhibition of Cdk 1/cyclinB 1 kinase activity. The DATS-treated PC-3 and DU 145 cells also exhibited a decrease in the protein level of Cdc 25 C and an increase in its Ser(216) phosphorylation. The DATS-mediated decrease in protein level and Ser(216) phosphorylation of Cdc 25 C as well as G(2)-M phase cell cycle arrest were significantly attenuated in the presence of N-acetylcysteine implicating reactive oxygen species (ROS) in cell cycle arrest caused by DATS. ROS generation was observed in DATS-treated PC-3 and DU 145 cells. DATS treatment also caused an increase in the protein level of Cdk inhibitor p21, but DATS-induced G(2)-M phase arrest was not affected by antisense-mediated suppression of p21 protein level. In conclusion, the results of the present study indicate that DATS-induced G(2)-M phase cell cycle arrest in human prostate cancer cells is caused by ROS-mediated destruction and hyperphosphorylation of Cdc 25 C.
以大蒜衍生的癌症化学预防剂二烯丙基三硫化物（DATS）导致细胞周期停滞的分子机制已使用PC-3和DU 145人前列腺癌细胞作为模型进行了研究。用生长抑制浓度的DATS处理PC-3和DU 145细胞，但不处理正常前列腺上皮细胞系（PrEC），导致G(2)-M期细胞比例增加。DATS诱导PC-3细胞的细胞周期停滞与细胞周期蛋白依赖性激酶1（Cdk 1）的Tyr(15)磷酸化增加以及Cdk 1/细胞周期蛋白B 1激酶活性的抑制有关。经DATS处理的PC-3和DU 145细胞还表现出Cdc 25 C蛋白水平降低及其Ser(216)磷酸化增加。在存在N-乙酰半胱氨酸的情况下，DATS介导的Cdc 25 C蛋白水平降低及其Ser(216)磷酸化以及G(2)-M期细胞周期停滞均显著减弱，这表明活性氧（ROS）参与了DATS引起的细胞周期停滞。在经DATS处理的PC-3和DU 145细胞中观察到了ROS生成。DATS处理还导致细胞周期蛋白依赖性激酶抑制剂p21的蛋白水平增加，但DATS诱导的G(2)-M期停滞不受反义介导的p21蛋白水平抑制的影响。总之，本研究结果表明，DATS诱导人前列腺癌细胞的G(2)-M期细胞周期停滞是由ROS介导的Cdc 25 C破坏和过度磷酸化引起的。
