LPL在U251细胞中的表达及核质穿梭对其增殖、生长的影响

Expression of LPL in U251 cells and effect of nucleocytoplasmic shuttling on their proliferation and growth

目的:观察脂蛋白脂肪酶(lipoprotein lipas,LPL)在人胶质瘤U251细胞系中的表达及在leptomycin B(LMB)作用下对其增殖、生长的影响。方法:将经体外培养的U251细胞加入染色体区域稳定蛋白1(CRM1)抑制剂LMB后,分别于12 h和24 h观察细胞核与细胞质LPL表达情况,并利用MTT和流式细胞术检测细胞增殖和凋亡。结果:加入5、10 nmol/L的LMB孵育12 h和24 h后,细胞核内LPL的表达明显增加,且呈剂量依赖性变化,其中10 nmol/L的LMB孵育24 h,细胞核内LPL增高最明显;MTT显示,对照组和各实验组A值分别为(0.82±0.08)、(0.71±0.03)、(0.70±0.04)、(0.69±0.07)和(0.68±0.09),各实验组和对照组之间差异有统计学差异(P<0.05);流式细胞术检测显示各实验组与对照组U251细胞的凋亡率分别为2.81±0.33、4.17±0.24、5.25±0.31和6.80±0.42,各实验组与对照组间差异有统计学差异(P<0.05)。结论:LPL在U251细胞中的核质穿梭是依赖CRM1的,且LMB可以显著增加LPL在细胞核内的表达。随着LMB的浓度增加和孵育时间的延长,U251细胞的增殖和凋亡也受到显著的影响,提示核质穿梭可能对肿瘤的生长有一定的影响。

Objective：To observe the expression of lipoprotein lipas（LPL）in human glioma cell lines U251 and the effects of nucleocytoplasmic shuttling on their proliferation and growth. Methods：After being incubated with leptomycin B（LMB）for 12 and 24 hours,the cytoplasmic and nuclear proteins of human glioma cells were islolated and analyzed by Western blot;MTT and flow cytometry were used to investigate the cell proliferation and necrosis. Results：After 5 nmol/L and 10 nmol/L of LMB being added,the cells were incubated for 12 and 24 hours;the expression of LPL in the nucleus was significantly increased in a dose dependent manner. The nucleus LPL dramatically increased when LMB incubating for 24 hours at concentration of 10 nmol/L. MTT showed that with the increase of LMB concentration and the extension of the incubation time,the cells proliferation was obviously inhibited [the A value were（0.82±0.08）,（0.71±0.03）,（0.70 ± 0.04）,（0.69 ± 0.07）,（0.68±0.09）,respectively]. U251 cell apoptosis rate was also significantly increased [（2.81±0.33）,（4.17±0.24）,（5.25±0.31）,（6.80±0.42）,respetcively] based on results of flow cytometry.Conclusion：LPL in human glioma U251 cells in nucleocytoplasmic shuttle is CRM1 dependent and CRM1 inhibitor LMB can significantly increase the expression of LMB in the nucleus. With increasing of LMB concentrations and incubation time,the proliferation and apoptosis of U251 cells are also significantly influenced,revealing that nucleocytoplasmic shuttling may have certain effect on the tumor development.