Sp1在 NK／T 细胞淋巴瘤细胞株中的表达及其对细胞侵袭的影响

Expression of Sp1 in NK/T cell lymphoma cell lines and its influence on cell invasion

目的：观察转录因子 Sp1在 NK／T 细胞淋巴瘤（NK／TCL）细胞株中的表达及其对细胞侵袭的影响。方法采用实时荧光定量聚合酶链反应（PCR）、免疫荧光和 Western blot 法测定 NK／TCL 细胞株 SNK-1、SNK-6和健康人 NK 细胞中 Sp1的表达；采用 Sp1抑制剂光神霉素 A（MIT）作用于 NK／TCL细胞株后，用实时荧光定量 PCR 和 Western blot 法检测 Sp1、胰岛素样生长因子1受体（IGF-1R）和基质金属蛋白酶2（MMP-2）的表达；采用 Transwell 实验观察 MIT 对细胞侵袭力的影响。结果 NK／TCL 细胞株SNK-1、SNK-6中 Sp1基因和蛋白高表达。其中基因的表达水平分别是健康人 NK 细胞的（9.4±0.3）倍和（10.6±0.3）倍（P＝0.0052，P＝0.0037），蛋白的表达水平分别是健康人 NK 细胞的（5.4±0.3）倍和（8.6±0.5）倍（P＝0.0083，P＝0.0069）。100 nmol／L MIT 抑制 Sp1后，与二甲基亚砜处理的对照组相比，细胞株中 IGF-1R 的基因表达量分别下降了（83.9±3.7）%和（65.8±4.2）%（P＝0.0082，P＝0.0097），蛋白表达量分别下降了（51.5±7.1）%和（49.6±9.1）%（P＝0.0178，P＝0.0155）。100 nmol／L MIT 处理细胞后 SNK-1、SNK-6细胞的侵袭率分别下降了（29.6±6.4）%和（37.2±7.6）%（P＝0.0418，P＝0.0372），MMP-2蛋白表达量分别是对照组蛋白表达量的（52.7±4.7）%、（29.7±5.6）%（P＝0.0286，P＝0.0202）。结论 NK／TCL细胞株高表达 Sp1，其可能通过正调控 IGF-1R 增强 MMP-2的表达，进而提高 NK／TCL 细胞的侵袭力。

Objective To identify the expression of transcription factor Sp1 in NK/T-cell lymphoma （NK/TCL） cell lines and to investigate the role of Sp1 in regulation of cell invasion. Methods Real-time PCR, immunofluorescence and Western blot were performed to detect the expression of Sp1 in NK/TCL cell lines SNK-1 and SNK-6 and normal NK cells. Expression levels of IGF-1R and MMP-2 were measured by real-time PCR and Western blot, respectively. Transwell assay was applied to observe the effects of mythramycin A（MIT） on cell invasion. Results Sp1 expression in mRNA and protein were over-expression in NK/TCL cell lines SNK-1 and SNK-6 when compared with normal NK cells. Inhibition of Sp1 by MIT remarkably reduced expression of IGF-1R and MMP-2 in SNK-1, SNK-6 and as a result, or significantly suppressed cell invasion. Expression levels of Sp1 mRNA in SNK-1 and SNK-6 were （9.4±0.3） and （10.6±0.3） foldsincrease as compared with that of control group, respectively （P=0.005 2, P=0.003 7）. Levels of Sp1 protein were （5.4±0.3） and （8.6±0.5） foldsincrease times than control groups, respectively （P=0.008 3, P=0.006 9）. Inhibition of Sp1 by MIT （100 nmol/L） remarkably reduced expression levels of IGF-1R mRNA by （83.9±3.7） % and （65.8±4.2） % （P = 0.008 2, P = 0.009 7） as compared with controls. Meanwhile, levels of IGF-1R protein were reduced by （51.5±7.1） % and （49.6±9.1） % （P = 0.017 8, P = 0.015 5） as compared with＆amp;nbsp;control group. Inhibition of Sp1 by MIT （100 nmol/L） significantly reduced cell invasion and MMP-2 expression in the two cell lines,the cell invasion rates were reduced by （29.6±6.4） % and （37.2±7.6） % （P =0.041 8, P = 0.037 2） in SNK-1 and SNK-6 as compared with control group. The MMP-2 protein levels were found to be （52.7±4.7） % and （29.7±5.6） % （P = 0.028 6, P = 0.020 2） of control group. Conclusion Sp1 is over-expressed in NK/TCL cell lines, and it promotes NK/TCL cell invasion by up-regulating IGF-1R and further increasing MMP-2 expression.