Structure and Regulation of the Versican Promoter THE VERSICAN PROMOTER IS REGULATED BY AP-1 AND TCF TRANSCRIPTION FACTORS IN INVASIVE HUMAN MELANOMA CELLS
Structure and Regulation of the Versican Promoter THE VERSICAN PROMOTER IS REGULATED BY AP-1 AND TCF TRANSCRIPTION FACTORS IN INVASIVE HUMAN MELANOMA CELLS
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DOI：
10.1074/jbc.m807108200
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发表时间：
2009-05-01
影响因子：
4.8
通讯作者：
Bassols, Anna
中科院分区：
文献类型：
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作者：
Domenzain-Reyna, Clelia;Hernandez, Daniel;Bassols, Anna
Versican是细胞外基质的一种大的硫酸软骨素蛋白聚糖，参与多种细胞过程。我们以前表明，多功能蛋白聚糖，这是过度表达在皮肤黑色素瘤以及癌前病变，有助于黑色素瘤的进展，有利于细胞的分离和转移性传播。在这里，我们研究了多功能蛋白聚糖启动子在黑色素瘤细胞系中的转录调控与不同水平的生物侵略性和分化阶段。我们发现，多功能蛋白聚糖启动子上调占的mRNA和蛋白质的表达水平的差异检测在侵袭性SK-mel-131人黑色素瘤细胞。与在非侵袭性MeWo黑素瘤细胞中测量的相比，多功能蛋白聚糖启动子的活性在这些细胞中增加了5倍。在近端启动子中鉴定了几个转录调控元件，包括AP-1、Sp1、AP-2和两个TCF-4位点。我们发现，启动子激活是由ERK/MAPK和JNK信号通路作用于AP-1位点介导的，这表明SK-mel-131细胞中存在的BRAF突变通过ERK/MAPK通路引起的信号传导影响多功能蛋白聚糖基因的上调。这是首次发现AP-1转录因子家族与多功能蛋白聚糖的表达调控有关。此外，TCF-4结合位点的缺失导致SK-mel-131细胞中启动子活性降低60%。这些结果显示AP-1和TCF-4结合位点是指导多功能蛋白聚糖产生的主要调控区域，为黑色素瘤进展期间多功能蛋白聚糖启动子调控提供了新的见解。
Versican is a large chondroitin sulfate proteoglycan of the extracellular matrix that is involved in a variety of cellular processes. We showed previously that versican, which is overexpressed in cutaneous melanomas as well as in premalignant lesions, contributes to melanoma progression, favoring the detachment of cells and the metastatic dissemination. Here, we investigated the transcriptional regulation of the versican promoter in melanoma cell lines with different levels of biological aggressiveness and stages of differentiation. We show that versican promoter up-regulation accounts for the differential expression levels of mRNA and protein detected in the invasive SK-mel-131 human melanoma cells. The activity of the versican promoter increased 5-fold in these cells in comparison with that measured in non-invasive MeWo melanoma cells. Several transcriptional regulatory elements were identified in the proximal promoter, including AP-1, Sp1, AP-2, and two TCF-4 sites. We show that promoter activation is mediated by the ERK/MAPK and JNK signaling pathways acting on the AP-1 site, suggesting that BRAF mutation present in SK-mel-131 cells impinge upon the up-regulation of the versican gene through signaling elicited by the ERK/MAPK pathway. This is the first time the AP-1 transcription factor family has been shown to be related to the regulation of versican expression. Furthermore, deletion of the TCF-4 binding sites caused a 60% decrease in the promoter activity in SK-mel-131 cells. These results showing that AP-1 and TCF-4 binding sites are the main regulatory regions directing versican production provide new insights into versican promoter regulation during melanoma progression.