蛋白酶体抑制剂在TRAIL诱导恶性淋巴瘤细胞凋亡中的协同作用

Synergistic Effects of Proteasome Inhibitor on TRAIL-induced Apoptosis in Malignant Lymphoma Cells

目的:探讨合理应用蛋白酶体抑制剂PS-341协同TRAIL有效增加耐药恶性淋巴瘤细胞凋亡的内在机制,为耐药肿瘤的治疗提供新思路。方法:采用流式细胞仪、Western Blot、荧光显色技术观察PS-341与TRAIL协同作用后恶性淋巴瘤细胞CRL的凋亡情况、促凋亡蛋白Bax的表达水平以及Caspase-3的活性变化。结果:TRAIL作用细胞24h凋亡率仅为21.3%,并且出现Bax蛋白表达水平的下降,6h的表达量仅为正常量的5/9;联合使用浓度为10nmol/L PS-341后显著增加细胞的凋亡,24h凋亡指数为50.4%;6h Bax蛋白表达量为正常量的1.2倍,Caspase-3酶活性增加至122.56±1.434μmol/L·h^(-1)·mg^(-1)蛋白。结论:合理使用蛋白酶体抑制剂可通过有效抑制凋亡蛋白Bax降解,逆转恶性淋巴瘤细胞对TRAIL的药物抵抗,为合理用药提供理论依据。

Objective： To explore the synergistic mechanisms of proteasome inhibitor on TRAIL-induced apoptosis in malignant lymphoma cells and to offer new ideas for clinical treatment of drug-resistant tumors. Methods： The apoptosis index, Caspase-3 activity and Bax protein level were detected in malignant lymphoma CRL cells using flow cytometry, Western blot and fluorometry. The CRL cells were treated with PS-341, with or without TRAIL. Results： The CRL cells were resistant to the TRAIL-induced apoptosis and the apoptosis rate of TRAIL-treated cells at 24h was only 21.3% of the level found in untreated CRL cells. Bax protein was degraded during the PS-341 treatment and the Bax expression level at 6h was 5/9 of the level found in untreated cells. The apoptosis index increased significantly when the working concentration reached 10nmol/L PS-341. At that concentration, the apoptosis index at 24h was 50.4%, and the expression of Bax protein was 1.2 times the level found in untreated cells. The Caspase-3 enzyme activity was increased to 122.56±1.434μmol/L·h^-1·mg^-1 protein. Conclusions： Reasonable use of the proteasome inhibitor PS-341 can effectively inhibit the degradation of the apoptotic protein Bax and reverse TRAIL resistance of malignant lymphoma cells, thus supplying a theoretical base for reasonable administration.