目的:检测转录因子Sp1在NK/T细胞淋巴瘤(NK/TCL)细胞株中的表达,探讨Sp1对肿瘤细胞侵袭的作用及其可能的调控机制.方法:利用Real-time PCR、免疫荧光技术和蛋白质免疫印迹技术检测Sp1的表达,Real-time PCR技术和蛋白质免疫印迹技术检测血管内皮生长因子(VEGF)和基质金属蛋白酶(MMP)2的表达,Transwell技术观察Sp1抑制剂光神霉素A(MIT)对细胞侵袭能力的影响.结果:NK/TCL细胞株SNK 1、SNK-6和SNT-8均高表达Sp1.MIT显著抑制SNK-1、SNK-6和SNT-8中VEGF基因和蛋白水平的表达,MMP2蛋白的表达以及细胞的侵袭能力.结论:NK/TCL肿瘤细胞株中存在高表达的Sp1,并可促进肿瘤细胞的侵袭.Sp1可通过调控VEGF和MMP2的表达影响细胞的侵袭力.

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 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.

生长因子是一类与受体结合后可以促进细胞增殖和调节细胞多项功能的多肽分子.生长因子及其受体信号通路包括Ras/MAPK、PI3K/AKT和STAT等不仅调控正常细胞的生物学行为,对恶性肿瘤细胞增殖、分化、转化和迁移也具有重要意义.研究发现多种生长因子如VEGF、PDGF和IGF及其受体在多种实体肿瘤如肺癌、乳腺癌、结肠癌中发现有异常表达,在淋巴瘤如DLBCL、PTCL、ML和NL中也存在异常的共同表达,提示在淋巴瘤中可能构成生长因子及其受体的自分泌/旁分泌环路.生长因子及其受体的表达对淋巴瘤患者的预后有一定指导意义,临床研究发现表达生长因子或其受体阳性患者比表达阴性患者有较差的临床预后.这可能与生长因子及其受体对淋巴瘤细胞的增殖、转移和耐药调控有关.目前生长因子及其受体已成为潜在的药物靶点,多种生长因子及其受体抑制剂在开发和临床试验中.本文就近年来生长因子及其受体在淋巴瘤中异常表达研究进展作简要综述.