Expression of Sp1 in NK/T cell lymphoma cell lines and its influence on cell invasion / 白血病·淋巴瘤

ABSTRACT

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.