Kang Jung-Hoon, Kim Myung-Jun, Chang Seo-Yoon, Sim Sang Soo, Kim Myung-Suk, Jo Yang-Hyeok
Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea.
J Cell Biochem. 2008 Jul 1;104(4):1192-203. doi: 10.1002/jcb.21697.
Histone deacetylase (HDAC) inhibitors have been reported to inhibit angiogenesis as well as tumor growth. Thrombospondin-1 (TSP1) has been recognized as a potent inhibitor of angiogenesis. Such an action of TSP1 may account for the effect of HDAC inhibitors. In the present study, we investigated the molecular mechanism by which trichostatin A, a HDAC inhibitor, induces the expression of TSP1 gene. Trichostatin A increased both mRNA and protein levels of TSP1 in HeLa cells. Promoter and actinomycin D chase assays showed that trichostatin A-induced TSP1 expression was regulated at the transcriptional level without changing mRNA stability. CCAAT box on the TSP1 promoter was found to primarily mediate the trichostatin A response by deletion and mutation analyses of the TSP1 promoter. Electrophoretic mobility shift assay indicated that CCAAT-binding factor (CBF) was specifically bound to the CCAAT box of TSP1 promoter. Moreover, chromatin immunoprecipitation assay showed that trichostatin A increased the binding of acetylated form of histone H3 to the CCAAT box region of TSP1 promoter. Taken together, these results strongly suggest that trichostatin A activates the transcription of TSP1 gene through the binding of transcription factor CBF to CCAAT box and the enhanced histone acetylation. Thus, the present study provides the clue that the inhibition of angiogenesis by trichostatin A is accomplished through the upregulation of TSP1, the anti-angiogenic factor.
据报道，组蛋白脱乙酰酶（HDAC）抑制剂可抑制血管生成以及肿瘤生长。血小板反应蛋白-1（TSP1）已被公认为一种有效的血管生成抑制剂。TSP1的这种作用可能解释了HDAC抑制剂的作用效果。在本研究中，我们探究了HDAC抑制剂曲古抑菌素A诱导TSP1基因表达的分子机制。曲古抑菌素A增加了HeLa细胞中TSP1的mRNA和蛋白质水平。启动子和放线菌素D追踪试验表明，曲古抑菌素A诱导的TSP1表达在转录水平受到调控，而mRNA稳定性未发生改变。通过对TSP1启动子进行缺失和突变分析发现，TSP1启动子上的CCAAT盒主要介导曲古抑菌素A的反应。电泳迁移率变动分析表明，CCAAT结合因子（CBF）特异性结合至TSP1启动子的CCAAT盒。此外，染色质免疫沉淀试验表明，曲古抑菌素A增加了组蛋白H3的乙酰化形式与TSP1启动子的CCAAT盒区域的结合。综上所述，这些结果强烈表明，曲古抑菌素A通过转录因子CBF与CCAAT盒的结合以及组蛋白乙酰化增强来激活TSP1基因的转录。因此，本研究提供了线索，即曲古抑菌素A通过上调抗血管生成因子TSP1来实现对血管生成的抑制。
