Guo S-Y, Shen X, Yang J, Yuan J, Yang R-L, Mao K, Zhao D-H, Li C-J
Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Life Sciences College, Nanjing Normal University, Nanjing, China.
Braz J Med Biol Res. 2007 May;40(5):621-31. doi: 10.1590/s0100-879x2007000500004.
The tissue inhibitor of metalloproteinases (TIMP)-1 is a multifunctional protein which is not only an inhibitor of matrix metalloproteinases (MMPs) but also to have a possible "cytokine-like" action. Here, we first compared mRNA expression of TIMP-1 and MMP-9 in BEL-7402 (a hepatocellular carcinoma cell line), L-02 (a normal liver cell line) and QSG-7701 (a cell line derived from peripheral tissue of liver carcinoma) using real-time quantitative RT-PCR. By evaluating the variation of the MMP-9/TIMP-1 ratio as an index of reciprocal changes of the expression of the two genes, we observed that the MMP-9/TIMP-1 ratio was about 13- and 5-fold higher in BEL-7402 than in L-02 and QSG-7701, respectively. Significantly, overexpression of TIMP-1 decreased the MMP-9/TIMP-1 ratio in BEL-7402 and then inhibited the cell growth to 60% and reduced the migration to about 30%. Meanwhile, our data showed that interleukin-6 (IL-6) (100 ng/mL) could also inhibited the cell growth of BEL-7402. Further studies indicated that TIMP-1 mediated the inhibitory effect of IL-6 on BEL-7402 cell proliferation in a STAT3-dependent manner, which could further accelerate the expression of the cyclin-dependent kinase inhibitor p21. A dominant negative STAT3 mutant totally abolished IL-6-induced TIMP-1 expression and its biological functions. The present results demonstrate that TIMP-1 may be one of the mediators that regulate the inhibitory effect of IL-6 on BEL-7402 proliferation in which STAT3 signal transduction and p21 up-regulation also play important roles.
金属蛋白酶组织抑制剂（TIMP）-1是一种多功能蛋白，它不仅是基质金属蛋白酶（MMPs）的抑制剂，还可能具有“细胞因子样”作用。在此，我们首先使用实时定量逆转录聚合酶链反应比较了BEL-7402（一种肝癌细胞系）、L-02（一种正常肝细胞系）和QSG-7701（一种源自肝癌外周组织的细胞系）中TIMP-1和MMP-9的mRNA表达。通过评估MMP-9/TIMP-1比值的变化作为这两个基因表达相互变化的指标，我们观察到BEL-7402中的MMP-9/TIMP-1比值分别比L-02和QSG-7701高约13倍和5倍。值得注意的是，TIMP-1的过表达降低了BEL-7402中的MMP-9/TIMP-1比值，进而将细胞生长抑制至60%，并将迁移率降低至约30%。同时，我们的数据表明白细胞介素-6（IL-6）（100 ng/mL）也能抑制BEL-7402的细胞生长。进一步的研究表明，TIMP-1以STAT3依赖的方式介导IL-6对BEL-7402细胞增殖的抑制作用，这可能进一步加速细胞周期蛋白依赖性激酶抑制剂p21的表达。一种显性负性STAT3突变体完全消除了IL-6诱导的TIMP-1表达及其生物学功能。目前的结果表明，TIMP-1可能是调节IL-6对BEL-7402增殖抑制作用的介质之一，其中STAT3信号转导和p21上调也起重要作用。
