Promoter identification and transcriptional regulation of the metastasis gene MACC1 in colorectal cancer
Promoter identification and transcriptional regulation of the metastasis gene MACC1 in colorectal cancer
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DOI：
10.1016/j.molonc.2013.05.003
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发表时间：
2013-10-01
影响因子：
6.6
通讯作者：
Stein, Ulrike
中科院分区：
文献类型：
--
作者：
Juneja, Manisha;Ilm, Katharina;Stein, Ulrike
MACC1，结肠癌相关转移1，是一种新发现的预测结直肠癌转移和患者生存的预后生物标志物，当在原发肿瘤或患者血液中确定时。MACC1在细胞培养中诱导细胞运动和增殖，并在小鼠模型中诱导转移。MACC1通过与其启动子结合，作为受体酪氨酸激酶基因Met的转录调节因子。然而，到目前为止，关于MACC1基因的启动子及其转录调控的信息还没有报道。在这里，我们报告了使用引导MACC1转录的启动子荧光素酶结构来鉴定MACC1启动子的方法。为了深入了解该启动子区域内的重要结构域，我们构建了5‘端截短缺失结构。我们的结果表明，426-18区域是AP-1、Sp1和C/EBP转录因子结合的核心启动子和功能基序，定点突变研究证实了这一点。利用凝胶迁移率改变分析和染色质免疫沉淀分析，我们证明了这些转录因子与最小必需的MACC1核心启动子序列的物理相互作用。用RNA干扰策略敲除这些转录因子可降低Mac1的表达(P<；0.001)，并导致细胞迁移减少(P<；0.01)，这可以通过异位过表达Macc1而被特异性地拯救。在大肠肿瘤中，c-jun和Sp1的表达水平与MACC1值显著相关(P=0.0007.0 5和P=0.0 2)。重要的是，c-jun和Sp1的表达水平与异时转移的发生密切相关(分别为P=0.01P=0.001)。这是首次鉴定MACC1启动子以及AP-1和Sp1对其转录调控的研究。了解MACC1基因的转录调控将有助于更好地了解其在癌症进展和转移中的作用。(C)2013年欧洲生化学会联合会。爱思唯尔出版，版权所有。
MACC1, Metastasis associated in colon cancer 1, is a newly identified prognostic biomarker for colorectal cancer metastasis and patient survival, when determined in the primary tumor or patient blood. MACC1 induces cell motility and proliferation in cell culture and metastasis in mouse models. MACC1 acts as a transcriptional regulator of the receptor tyrosine kinase gene Met via binding to its promoter. However, no information about the promoter of the MACC1 gene and its transcriptional regulation has been reported so far. Here we report the identification of the MACC1 promoter using a promoter luciferase construct that directs transcription of MACC1. To gain insights into the essential domains within this promoter region, we constructed 5' truncated deletion constructs. Our results show that the region from 426 to 18 constitutes the core promoter and harbors functional motifs for the binding of AP-1, Sp1, and C/EBP transcription factors as validated by site directed mutagenesis study. Using electrophoretic mobility shift assay and chromatin immunoprecipitation assay, we demonstrated the physical interaction of these transcription factors to a minimal essential MACC1 core promoter sequence. Knock down of these transcription factors using RNAi strategy reduced MACC1 expression (P < 0.001), and resulted in decrease of cell migration (P < 0.01) which could be specifically rescued by ectopic overexpression of MACC1. In human colorectal tumors, expression levels of c-Jun and Sp1 correlated significantly to MACC1 (P = 0.0007 and P = 0.02, respectively). Importantly, levels of c-Jun and Sp1 also showed significant correlation to development of metachronous metastases (P = 0.01 and P = 0.001, respectively). This is the first study identifying the MACC1 promoter and its transcriptional regulation by AP-1 and Sp1. Knowledge of the transcriptional regulation of the MACC1 gene will implicate in enhanced understanding of its role in cancer progression and metastasis. (C) 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.