β-catenin activation down-regulates cell-cell junction-related genes and induces epithelial-to-mesenchymal transition in colorectal cancers
β-catenin activation down-regulates cell-cell junction-related genes and induces epithelial-to-mesenchymal transition in colorectal cancers
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DOI：
10.1038/s41598-019-54890-9
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发表时间：
2019-12-05
影响因子：
4.6
通讯作者：
Kim, Hoguen
中科院分区：
文献类型：
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作者：
Kim, Won Kyu;Kwon, Yujin;Kim, Hoguen
结直肠癌（CRC）中的WNT信号激活通过APC失活或β-连环蛋白突变发生。这两个过程都促进β-连环蛋白核积累，从而上调上皮细胞向间充质细胞转化（EMT）。我们研究了含有野生型（HCT 116-WT）或突变型β-连环蛋白等位基因（HCT 116-MT）的HCT 116细胞，或含有WT和突变型等位基因（HCT 116-P）的亲本细胞的β-连环蛋白定位、转录组和表型差异。然后我们分析了结直肠癌组织中β-连环蛋白的表达和相关的表型。野生型β-连环蛋白显示膜定位，而突变体显示核定位;在HCT 116-P中观察到核和非核定位。微阵列分析显示，与HCT 116-WT相比，HCT 116-MT中Claudin-7和E-cadherin下调。紧密连接蛋白-7也在HCT 116-P中相对于HCT 116-WT下调，而没有E-钙粘蛋白失调。我们发现ZEB 1是突变型β-连环蛋白介导的HCT 116-P和HCT 116-MT细胞中E-钙粘蛋白和Claudin-7丢失的关键EMT因子。我们还证明了E-钙粘蛋白与WT和突变型β-连环蛋白结合，E-钙粘蛋白的缺失从细胞膜释放β-连环蛋白并导致其降解。Claudin-7的改变以及Claudin-7和E-cadherin的改变分别导致HCT 116-P的紧密连接（TJ）受损，以及HCT 116-MT的TJ和粘附连接（AJs）的双重丧失。TJ损失增加细胞运动性，随后的AJ损失进一步上调。101例CRC的免疫组化分析显示高（14.9%）、低（52.5%）和不可检测（32.6%）的β-连环蛋白核表达，且高β-连环蛋白核表达与CRC患者的总生存率显著相关（P = 0.009）。我们的研究结果表明，β-连环蛋白激活通过修饰细胞-细胞连接诱导EMT进展，从而有助于CRC的侵袭性。
WNT signaling activation in colorectal cancers (CRCs) occurs through APC inactivation or beta-catenin mutations. Both processes promote beta-catenin nuclear accumulation, which up-regulates epithelial-to-mesenchymal transition (EMT). We investigated beta-catenin localization, transcriptome, and phenotypic differences of HCT116 cells containing a wild-type (HCT116-WT) or mutant beta-catenin allele (HCT116-MT), or parental cells with both WT and mutant alleles (HCT116-P). We then analyzed beta-catenin expression and associated phenotypes in CRC tissues. Wild-type beta-catenin showed membranous localization, whereas mutant showed nuclear localization; both nuclear and non-nuclear localization were observed in HCT116-P. Microarray analysis revealed down-regulation of Claudin-7 and E-cadherin in HCT116-MT vs. HCT116-WT. Claudin-7 was also down-regulated in HCT116-P vs. HCT116-WT without E-cadherin dysregulation. We found that ZEB1 is a critical EMT factor for mutant beta-catenin-mediated loss of E-cadherin and Claudin-7 in HCT116-P and HCT116-MT cells. We also demonstrated that E-cadherin binds to both WT and mutant beta-catenin, and loss of E-cadherin releases beta-catenin from the cell membrane and leads to its degradation. Alteration of Claudin-7, as well as both Claudin-7 and E-cadherin respectively caused tight junction (TJ) impairment in HCT116-P, and dual loss of TJs and adherens junctions (AJs) in HCT116-MT. TJ loss increased cell motility, and subsequent AJ loss further up-regulated that. Immunohistochemistry analysis of 101 CRCs revealed high (14.9%), low (52.5%), and undetectable (32.6%) beta-catenin nuclear expression, and high beta-catenin nuclear expression was significantly correlated with overall survival of CRC patients (P = 0.009). Our findings suggest that beta-catenin activation induces EMT progression by modifying cell-cell junctions, and thereby contributes to CRC aggressiveness.