Kunz Manfred, Moeller Steffen, Koczan Dirk, Lorenz Peter, Wenger Roland H, Glocker Michael O, Thiesen Hans-Juergen, Gross Gerd, Ibrahim Saleh M
Department of Dermatology and Venereology and Institute of Immunology and Proteome Center, University of Rostock, 18055 Rostock, Germany.
J Biol Chem. 2003 Nov 14;278(46):45651-60. doi: 10.1074/jbc.M301373200. Epub 2003 Aug 25.
Hypoxia has a profound influence on progression and metastasis of malignant tumors. In the present report, we used the oligonucleotide microarray technique to identify new hypoxia-inducible genes in malignant melanoma with a special emphasis on angiogenesis factors. A commercially available Affymetrix gene chip system was used to analyze five melanoma cell lines of different aggressiveness. A total of 160 hypoxia-inducible genes were identified, clustering in four different functional clusters. In search of putative angiogenesis and tumor progression factors within these clusters, Cyr61, a recently discovered angiogenesis factor, was identified. Cyr61 was hypoxia-inducible in low aggressive melanoma cells; however, it showed constitutive high expression in highly aggressive melanoma cells. Further analyses of transcriptional mechanisms underlying Cyr61 gene expression under hypoxia demonstrated that an AP-1 binding motif within the Cyr61 promoter plays a central role in the hypoxic regulation of Cyr61. It could be shown by use of in vitro luciferase assays, electrophoretic mobility shift assays, and immunoprecipitation that hypoxia-inducible factor-1alpha interacts with c-Jun/AP-1 and may thereby contribute to Cyr61 transcriptional regulation under hypoxia. Taken together, the presented data show that Cyr61 is a hypoxia-inducible angiogenesis factor in malignant melanoma with tumor stage-dependent expression. This may argue for a hypoxia-induced selection process during tumor progression toward melanoma cells with constitutive high Cyr61 expression.
缺氧对恶性肿瘤的进展和转移具有深远影响。在本报告中，我们使用寡核苷酸微阵列技术来鉴定恶性黑色素瘤中新型缺氧诱导基因，尤其着重于血管生成因子。使用市售的Affymetrix基因芯片系统分析五种不同侵袭性的黑色素瘤细胞系。共鉴定出160个缺氧诱导基因，它们聚集成四个不同的功能簇。在这些簇中寻找假定的血管生成和肿瘤进展因子时，发现了最近发现的血管生成因子Cyr61。Cyr61在低侵袭性黑色素瘤细胞中是缺氧诱导性的；然而，它在高侵袭性黑色素瘤细胞中呈组成性高表达。对缺氧条件下Cyr61基因表达的转录机制进行进一步分析表明，Cyr61启动子内的AP-1结合基序在Cyr61的缺氧调节中起核心作用。通过体外荧光素酶测定、电泳迁移率变动分析和免疫沉淀表明，缺氧诱导因子-1α与c-Jun/AP-1相互作用，从而可能在缺氧条件下促进Cyr61的转录调节。综上所述，所呈现的数据表明Cyr61是恶性黑色素瘤中一种缺氧诱导的血管生成因子，其表达具有肿瘤分期依赖性。这可能表明在肿瘤进展过程中存在缺氧诱导的选择过程，促使向具有组成性高Cyr61表达的黑色素瘤细胞发展。
