High cancer-specific expression of mesothelin (MSLN) is attributable to an upstream enhancer containing a transcription enhancer factor-dependent MCAT motif
High cancer-specific expression of mesothelin (MSLN) is attributable to an upstream enhancer containing a transcription enhancer factor-dependent MCAT motif
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DOI：
10.1158/0008-5472.can-07-0474
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发表时间：
2007-10-01
期刊：
影响因子：
11.2
通讯作者：
Kern, Scott E.
中科院分区：
文献类型：
--
作者：
Hucl, Tomas;Brody, Jonathan R.;Kern, Scott E.
识别具有癌症特异性过度表达的基因提供了以公正的方式有效地发现癌症特异性活动的可能性。我们应用这个范式来研究间皮蛋白(MSLN)的过度表达，这是胰腺癌几乎无处不在的、诊断和治疗有用的特征。我们鉴定了一个18bp的上游增强子，称为CanScrip，它强烈激活来自其他弱组织非特异性启动子的转录，并选择性地在具有癌症特异性MSLN转录异常升高的细胞中操作。将突变引入CanScript显示了两个功能上不同的位点：一个类似Sp1的位点和一个MCAT元件。凝胶滞留和染色质免疫沉淀实验表明MCAT元件在体内外均能与转录增强因子(TEF)-1(TEAD1)结合。通过TEF-1基因敲除实验确定MSLN蛋白的过表达需要TEF-1的存在。肿瘤的特异性似乎是由一个假定的限制辅因子TEF-1提供的，该辅因子只能在MSLN过表达的细胞系中被外源TEF-1击败。CanScrip串行器提供了增强的活动性。这些结果确定TEF家族成员是MSLN过度表达的主要调节因子，MSLN过度表达是胰腺癌和其他癌症的基本特征，可能是由于上游和频繁的细胞活动异常。CanScript序列代表了癌症特异性靶向的模块化元素，可能适用于近三分之一的人类恶性肿瘤。
Identification of genes with cancer-specific overexpression offers the potential to efficiently discover cancer-specific activities in an unbiased manner. We apply this paradigm to study mesothelin (MSLN) overexpression, a nearly ubiquitous, diagnostically and therapeutically useful characteristic of pancreatic cancer. We identified an 18-bp upstream enhancer, termed CanScript, strongly activating transcription from an otherwise weak tissue-nonspecific promoter and operating selectively in cells having aberrantly elevated cancer-specific MSLN transcription. Introducing mutations into CanScript showed two functionally distinct sites: an Sp1-like site and an MCAT element. Gel retardation and chromatin immunoprecipitation assays showed the MCAT element to be bound by transcription enhancer factor (TEF)-1 (TEAD1) in vitro and in vivo. The presence of TEF-1 was required for MSLN protein overexpression as determined by TEF-1 knockdown experiments. The cancer specificity seemed to he provided by a putative limiting cofactor of TEF-1 that could be outcompeted by exogenous TEF-1 only in a MSLN-overexpressing cell line. A CanScript concatemer offered enhanced activity. These results identify a TEF family member as a major regulator of MSLN overexpression, a fundamental characteristic of pancreatic and other cancers, perhaps due to an upstream and highly frequent aberrant cellular activity. The CanScript sequence represents a modular element for cancer-specific targeting, potentially suitable for nearly a third of human malignancies.