Endogenous Angiogenesis Inhibitor Blocks Tumor Growth via Direct and Indirect Effects on Tumor Microenvironment
Endogenous Angiogenesis Inhibitor Blocks Tumor Growth via Direct and Indirect Effects on Tumor Microenvironment
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DOI：
10.1016/j.ajpath.2011.07.035
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发表时间：
2011-11-01
影响因子：
6
通讯作者：
Stetler-Stevenson, William G.
中科院分区：
文献类型：
--
作者：
Bourboulia, Dimitra;Jensen-Taubman, Sandra;Stetler-Stevenson, William G.
基质金属蛋白酶组织抑制因子-2(TIMP-2)是一类抑制基质金属蛋白酶(MMPs)的内源性蛋白家族。TIMP-2通过基质金属蛋白酶依赖性和非依赖性机制抑制血管内皮细胞的增殖、迁移和体内血管生成。然而，关于这些机制对TIMP-2抗肿瘤作用的贡献，我们知之甚少。利用逆转录病毒传递系统，我们在人腺癌细胞A549中稳定高表达TIMP-2及其突变体Ala+TIMP-2(缺乏基质金属蛋白酶抑制活性)。实时荧光定量聚合酶链式反应和酶联免疫吸附试验证实TIMP-2的表达增强，逆转录酶谱证实TIMP-2的抑制活性增强。体外生长实验表明，TIMP-2和ALA+TIMP-2不改变基础细胞的增殖率，但抑制肿瘤细胞的迁移和侵袭。在体内，TIMP-2和ALA+TIMP-2 A549移植瘤生长速度减慢，CD31免疫染色显示瘤内微血管密度降低，TUNEL显示肿瘤细胞凋亡增加。免疫印迹和免疫组织化学分析显示，含有磷酸化FAK(Tyr397)和磷酸化AKT(Ser473)的A549移植瘤细胞TIMP-2和ALA+TIMP-2的活性均降低。我们得出结论，TIMP-2介导的肿瘤生长抑制作用至少部分地不依赖于对基质金属蛋白酶的抑制，是TIMP-2直接作用于肿瘤细胞和调节肿瘤微环境的结果。(Am J Pathol2011,179：2589-2600；doi：10.1016/j.ajpath.2011.07.035)
Tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) belongs to a small family of endogenous proteins that inhibits a group of enzymes, the matrix metalloproteinases (MMPs). TIMP-2 inhibits endothelial cell proliferation and migration in vitro and angiogenesis in vivo, through MMP-dependent and -independent mechanisms. However, little is known regarding the contribution of these mechanisms to the antitumor effects of TIMP-2. Using a retroviral delivery system, we stably overexpressed TIMP-2 and its mutant Ala+TIMP-2 (devoid of MMP inhibitory activity) in human adenocarcinoma A549 cells. Using real time PCR, and enzyme-linked immunosorbent assay (ELISA), we confirmed enhanced TIMP-2 expression and its MMP inhibitory activity by reverse zymography. In vitro, growth assays suggested that TIMP-2 and Ala+TIMP-2 did not alter basal cell proliferation rates, however, tumor cell migration and invasion were inhibited. In vivo, both TIMP-2 and Ala+TIMP-2 A549 xenografts exhibited reduced growth rate, CD31 immunostaining indicated decreased intratumoral microvascular density, and TUNEL demonstrated enhanced tumor cell apoptosis. Immunoblotting and immunohistochemical analyses of A549 xenograft tissues with either phospho-FAK (Tyr397) or phospho-AKT (Ser473) showed decreased activation in both TIMP-2 and Ala+TIMP-2 tumor cells. We conclude that TIMP-2-mediated inhibition of tumor growth occurs, at least in part, independently of MMP inhibition, and is a consequence of both direct effects of TIMP-2 on tumor cells and modulation of the tumor microenvironment. (Am J Pathol 2011, 179:2589-2600; DOI: 10.1016/j.ajpath.2011.07.035)