摘 要 目的: 探讨细胞周期蛋白依赖性激酶(cyclindependent kinases,CDKs)抑制剂roscovitine和DNA合成阻滞剂含羞草碱（mimosine）在Fas介导的白血病细胞凋亡过程中的作用及其可能的机制。 方法：以急性成淋巴细胞白血病细胞Molt4和急性T细胞白血病细胞Jurkat为靶细胞，用rhFasL、Roscovitine、Mimosine分别单独作用Molt4细胞18 h（Jurkat细胞8 h）、24 h、24 h，或rhFasL分别与后两者联合作用靶细胞，用流式细胞术检测cyclins的表达和细胞凋亡率,Western blotting法检测CDK2和CDK1的磷酸化水平。 结果： Fas介导的细胞凋亡定位于G1期，Roscovitine和Mimosine作用后均可使Fas介导的细胞凋亡率明显增加（P<0.05）。Roscovitine作用后G1期的cyclin D3和cyclin E表达升高，靶细胞被阻滞在G1期的比例明显升高，并下调CDK2 Thr160位点的磷酸化水平；Roscovitine和rhFasL共同作用后，CDK2 Thr160位苏氨酸磷酸化水平进一步减弱。Mimosine作用后 cyclin D3的表达下降和CDK2 Thr160位点磷酸化水平明显下降，靶细胞被完全阻滞在G1期。Mimosine和rhFasL共同作用后cyclin D3、E、A和B1均有所下降，CDK2 Thr160位苏氨酸和CDK1 Thr161位苏氨酸的磷酸化水平明显减弱。结论：Roscovitine和Mimosine均有协同rhFasL促进白血病细胞凋亡的作用，其机制与该两制剂阻滞细胞于G1期、抑制CKD2活性以及影响细胞周期蛋白表达有关。

Abstract Objective: To assess the roles of roscovitine (an inhibitor of DCK) and mimosine (DNA synthesis inhibitor) in Fasmediated leukemia cell apoptosis and to understand the possible mechanism. Methods: The target leukemia cell lines Molt4 and Jurkat were incubated with rhFasL, roscovitine and mimosine separately or with rhFasL+roscovitine or rhFasL+minosine for 18 h （Jurkat 8 h）, 24 h, and 24 h. Apoptotic cells were examined by Annexin V method or modified API method; cyclins expression were detected by cyclin/DNA biparameter flow cytometry; CDK1 and CDK2 activities were detected by Western blotting. Results: Fasmediated cell apoptosis was at G1 phase. Both roscovitine and mimosine significantly promoted Fasmediated apoptosis (P<0.05). Moreover, mimosine increased the levels of cycline D3 and cyclin E at G1 phase and more cells were arrested at G1phase; roscovitine also lowered the phosphorylation of CDK2 Thr160. Minosine+rhFasl decreased the phosphorylation of CDK2 Thr160, and the target cells were completely arrested at G1 phase; it also decreased the levels of cyclin D3, E, A and B1 and the phosphorylation of CDK2 Thr160 and CDK1 Thr161. Conclusion: Both roscovitine and mimosine have synergistic effects with rhFasL in inducing apoptosis of leukemia cells, which is related to the G1 phase cell arrest, inhibition of CKD2 activity and influence of cyclin proteins.

国家重点基础研究发展规划(973)资助项目(No. 2004CB518705)；国家自然科学基金资助项目(No. 30440024)