Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
Mol Cancer Ther. 2010 Jan;9(1):1-16. doi: 10.1158/1535-7163.MCT-09-0321. Epub 2010 Jan 6.
E-cadherin (E-cad) is an adhesion molecule associated with tumor invasion and metastasis. Its down-regulation is associated with poor prognosis for many epithelial tumor types. We have profiled E-cad in the NCI-60 cancer cell lines at the DNA, RNA, and protein levels using six different microarray platforms plus bisulfite sequencing. Here we consider the effects on E-cad expression of eight potential regulatory factors: E-cad promoter DNA methylation, the transcript levels of six transcriptional repressors (SNAI1, SNAI2, TCF3, TCF8, TWIST1, and ZFHX1B), and E-cad DNA copy number. Combined bioinformatic and pharmacological analyses indicate the following ranking of influence on E-cad expression: (1) E-cad promoter methylation appears predominant, is strongly correlated with E-cad expression, and shows a 20% to 30% threshold above which E-cad expression is silenced; (2) TCF8 expression levels correlate with (-0.62) and predict (P < 0.00001) E-cad expression; (3) SNAI2 and ZFHX1B expression levels correlate positively with each other (+0.83) and also correlate with (-0.32 and -0.30, respectively) and predict (P = 0.03 and 0.01, respectively) E-cad expression; (4) TWIST1 correlates with (-0.34) but does not predict E-cad expression; and (5) SNAI1 expression, TCF3 expression, and E-cad DNA copy number do not correlate with or predict E-cad expression. Predictions of E-cad regulation based on the above factors were tested and verified by demethylation studies using 5-aza-2'-deoxycytidine treatment; siRNA knock-down of TCF8, SNAI2, or ZFHX1B expression; and combined treatment with 5-aza-2'-deoxycytidine and TCF8 siRNA. Finally, levels of cellular E-cad expression are associated with levels of cell-cell adhesion and response to drug treatment.
E-钙黏蛋白（E-cad）是一种与肿瘤侵袭和转移相关的黏附分子。其下调与许多上皮肿瘤类型的不良预后相关。我们使用六种不同的微阵列平台加上亚硫酸氢盐测序，在 NCI-60 癌细胞系的 DNA、RNA 和蛋白质水平上对 E-cad 进行了分析。在这里，我们考虑了八个潜在调节因子对 E-cad 表达的影响：E-cad 启动子 DNA 甲基化、六个转录抑制因子（SNAI1、SNAI2、TCF3、TCF8、TWIST1 和 ZFHX1B）的转录水平以及 E-cad DNA 拷贝数。综合生物信息学和药理学分析表明，对 E-cad 表达的影响如下：（1）E-cad 启动子甲基化似乎占主导地位，与 E-cad 表达强烈相关，并且在超过 20%至 30%的阈值以上，E-cad 表达被沉默；（2）TCF8 表达水平与 E-cad 表达呈负相关（-0.62）并预测 E-cad 表达（P < 0.00001）；（3）SNAI2 和 ZFHX1B 表达水平相互呈正相关（+0.83），并且与 E-cad 表达呈负相关（-0.32 和-0.30），并预测 E-cad 表达（P = 0.03 和 0.01）；（4）TWIST1 与 E-cad 表达呈负相关（-0.34）但不预测 E-cad 表达；（5）SNAI1 表达、TCF3 表达和 E-cad DNA 拷贝数与 E-cad 表达不相关或不预测 E-cad 表达。基于上述因素的 E-cad 调节预测通过使用 5-氮杂-2'-脱氧胞苷处理进行去甲基化研究、TCF8、SNAI2 或 ZFHX1B 表达的 siRNA 敲低以及 5-氮杂-2'-脱氧胞苷和 TCF8 siRNA 的联合治疗进行了测试和验证。最后，细胞内 E-cad 表达水平与细胞间黏附水平和药物治疗反应相关。
