硼替佐米作用不同时间对K562耐药细胞株核因子-κB途径的影响

Effects of different time points of bortezomib on the pathway of NF-KB in drug-resistant K562 cells

目的观察硼替佐米（商品名：万珂，PS-341）对柔红霉素（DNR）诱导的K562耐药细胞株（K562／DNR）核因子-KB（NF-kB）、抑制蛋白KB（IKB）及P-糖蛋白（P-gP）表达的影响，探讨PS-341逆转耐药的分子机制。方法以100txg／mlDNR单用或联合应用4Pμg／LPS-341分别作用于K562／DNR12、24及36h，检测不同时间点各组NF-KB、IKB及P-gP表达情况，同时测定NF-KBp65活性，检测各组细胞凋亡率。结果Westernblot结果显示：与阴性对照组相比，DNR可诱导NF-kB表达上调及活性增强、IKB表达下调、P-gP表达上调；加用PS-341可显著抑制DNR诱导的NF-kB及P．gP表达，使IKB表达增加。加用PS-341后，NF．KB活性12h为（15．3±1．87）％[DNR组为（23．8±2．27）％]，24h为（10．2±1．69）％[DNR组为（25．4±1．98）％1，36h为（6．08±-2．53）％[DNR组为（26．9±2．58）％]，与相应单用DNR组相比均有明显下降，差异有统计学意义（P值均〈0．05）。DNR与PS-341联用后，细胞凋亡率12h为（35．23±5．15）％[DNR组为（15．56±4．12）％]，24h为（40．26±6．89）％[DNR组为（17．25±2．89）％]，36h为（43．58±7．69）％[DNR组为（22．47±4．58）％]，与DNR组相比，细胞凋亡率均明显增加，差异具有统计学意义（P值均〈0．05）。上述作用呈时间依赖性。结论PS-341可减少K562／DNR细胞NF-KB的活化，降低P-gP表达，逆转细胞耐药，促进细胞凋亡。

Objective To study the effects of bortezomib on the expression of NF-KB, IKB and P-gp of drug-resistant K562 cells induced by daunorubicin （K562/DNR）, to explore the molecular mechanism of drug-resistant reverse. Methods The expression of NF-kB, IkB and P-gp in K562/DNR cells were detected when the cells had been treated with 100 μg/ml DNR only or together with 4 p.g/L bortezomib for 12 h, 24 h and 36 h. The apoptosis rates were detected in each group respectively and the activity of NF-kB was detected by ELISA method. Results Compared with the control group, the expressions of NF-kB and P-gp in K562/ DNR could be increased and IKB was decreased after being treated with DNR. When K562/DNR were cultured with bortezomib, the expressions of NF-KB and P-gp induced by DNR were significantly suppressed and IkB was increased. The activity of NF-kB were detected in different time points： （15.3±1.87） % [（23.8±2.27） % in DNR group] at 12 h, （10.2±1.69） % [（25.4±1.98） % in DNR group] at 24 h, （6.08±2.53） % [（26.9± 2.58） % in DNR group] at 36 h. There were a significant differences between DNR group and DNR＋PS-341 group. The apoptosis rates were increased in DNR＋PS-341 group at different time points than those in DNR group, （35.23±5.15） % [（15.56±4.12） % in DNR group] at 12 h, （40.26±6.89） % [（17.25±2.89） % in DNR group] at 24 h, （43.58±7.69） % [（22.47±4.58） % in DNR group] at 36 h. The effcets showed the character of time-dependent pattern. Conclusion Bortezomib could downregulate the expressions of NF-KB and P-gp in K562/DNR, reverse the drug resistance and up-regulate the apoptotic rates in K562/DNR cells.