The MYC 3' Wnt-Responsive Element Drives Oncogenic MYC Expression in Human Colorectal Cancer Cells.
The MYC 3' Wnt-Responsive Element Drives Oncogenic MYC Expression in Human Colorectal Cancer Cells.
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DOI：
10.3390/cancers8050052
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发表时间：
2016-05-23
期刊：
影响因子：
5.2
通讯作者：
Yochum GS
中科院分区：
文献类型：
--
作者：
Rennoll SA;Eshelman MA;Raup-Konsavage WM;Kawasawa YI;Yochum GS
Wnt/β-catenin信号通路组分的突变通过下调下游靶基因（包括c-MYC原癌基因（MYC））的表达来驱动结直肠癌（CRC）。在CRC中控制致癌MYC表达的关键调控DNA增强子元件尚未完全阐明。在以前的报道中，我们将T细胞因子（TCF）和β-连环蛋白与MYC 3′ Wnt应答DNA元件（MYC 3′ WRE）的结合与HCT 116细胞中MYC的表达相关联。在这里，我们使用CRISPR/Cas9来确定这个元素是否是MYC的关键驱动因素。我们分离了一个克隆细胞群，该细胞群在MYC 3′ WRE内含有单个TCF结合元件（TBE）的缺失。这种缺失减少了TCF/β-连环蛋白与该调节元件的结合，并降低了MYC表达。使用RNA-Seq分析，我们发现调节代谢过程的基因表达改变，其中许多是已知的MYC靶基因。我们发现，3′ WRE-Mut细胞显示出降低的增殖能力，减少了克隆生长，并降低了体内形成肿瘤的可能性。这些发现表明MYC 3′ WRE是致癌MYC表达的关键驱动因子，并表明该元件可作为CRC的治疗靶点。
Mutations in components of the Wnt/β-catenin signaling pathway drive colorectal cancer (CRC) by deregulating expression of downstream target genes including the c-MYC proto-oncogene (MYC). The critical regulatory DNA enhancer elements that control oncogenic MYC expression in CRC have yet to be fully elucidated. In previous reports, we correlated T-cell factor (TCF) and β-catenin binding to the MYC 3′ Wnt responsive DNA element (MYC 3′ WRE) with MYC expression in HCT116 cells. Here we used CRISPR/Cas9 to determine whether this element is a critical driver of MYC. We isolated a clonal population of cells that contained a deletion of a single TCF binding element (TBE) within the MYC 3′ WRE. This deletion reduced TCF/β-catenin binding to this regulatory element and decreased MYC expression. Using RNA-Seq analysis, we found altered expression of genes that regulate metabolic processes, many of which are known MYC target genes. We found that 3′ WRE-Mut cells displayed a reduced proliferative capacity, diminished clonogenic growth, and a decreased potential to form tumors in vivo. These findings indicate that the MYC 3′ WRE is a critical driver of oncogenic MYC expression and suggest that this element may serve as a therapeutic target for CRC.