TSA诱导MOLT-4细胞中p21^(WAF1/Cip-1)表达的功能机制研究

The Mechanisms of p21^(WAF1/Cip-1)Expression in MOLT-4 Cell Line Induced by TSA

为了研究去乙酰化酶抑制剂TSA诱导MOLT-4细胞周期阻滞和凋亡反应中p21WAFl/Cip-1的表达及其功能, 以组蛋白去乙酰化酶抑制剂TSA处理急性淋巴细胞白血病细胞系MOLT-4,流式细胞仪和细胞吖啶橙染色、瑞士染 色检测细胞周期和凋亡,Western检测p21p21WAFl/Cip-1的表达。结果表明:组蛋白去乙酰化酶抑制剂TSA可有效的诱导 MOLT-4细胞发生G2／M阻滞和凋亡,并且呈现明显的剂量效应关系和时间效应关系;在此周期阻滞与凋亡反应过 程中,p21WAFl/Cip-1蛋白的表达水平在周期阻滞前快速增高,而在凋亡早期开始下降。p21WAFl/Cip-1分子在细胞中的表 达规律与TSA诱导的细胞G2／M阻滞和凋亡反应间存在明显的剂量效应关系和时间效应关系;蛋白酶体抑制剂 MG-132提升p21WAFl/Cip-1分子在细胞中的表达可以增进细胞的G2／M阻滞反应而延缓凋亡。结论:蛋白酶体途径参 与TSA诱导的MOLT-4细胞周期阻滞向凋亡转换过程中p21WAFl/Cip-1分子的降解调控;p21WAFl/Cip-1在TSA诱导的 MOLT-4细胞G2／M阻滞和凋亡反应中起着重要调节作用。

To investigate the function and molecular mechanism of p21WAF1/Cip-1 expression in MOLT-4 cells induced by HDAC inhibitor TSA, the expression pattern of p21WAF1/Cip-1 and the distribution of cell cycle in TSA treated cells were analyzed. The results showed that TSA could effectively induce G2/M arrest and apoptosis of MOLT-4 cells. Kinetic experiments demonstrated that p21WAF1/Cip-1 were upregulated quickly before cell arrested in G2/M and began decreasing at the early stage of apoptosis. Meanwhile, the proteasome inhitor MG-132 could inhibit the decrease of p21WAF1/Cip-1 at the early stage of apoptosis, which showed that proteasome pathway involved in p21WAF1/Cip-1 degradation during the TSA induced G2/M arrest and apoptosis responses. This study also identified that the protein level of p21WAF1/Cip-1 was highly associated with the cell cycle change induced by TSA. Compared to cells treated by TSA only, exposure MOLT-4 cells to TSA meanwhile treatment with MG-132 increased the protein level of p21WAF1/Cip-1 and increased the numbers of cell in G2/M - phase, whereas the cell apoptosis were delayed. It is concluded that p21WAF1/Cip-1 plays a significant role in G2/M arrest and apoptosis signaling induced by TSA in MOLT-4 cells.