Medical Genomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Korea.
Carcinogenesis. 2012 Aug;33(8):1494-501. doi: 10.1093/carcin/bgs178. Epub 2012 May 18.
In this study, the promoter of the gene coiled-coil domain-containing 67 (CCDC67) was found to be frequently methylated in gastric cancer cell lines and in primary gastric tumors, as examined by restriction landmark genomic scanning. In addition, CCDC67 expression was down-regulated in 72.7% of gastric cancer cell lines tested. In most cases, gene down-regulation was associated with CpG hypermethylation in the CCDC67 promoter. Treatment with 5-aza-2'-deoxycytidine and/or trichostatin A restored CCDC67 expression in down-regulated cell lines. Pyrosequencing analysis of 150 paired primary gastric cancer samples revealed that promoter CpG methylation was increased in 74% of tested tumors compared with paired adjacent normal tissues, and this hypermethylation correlated significantly with down-regulation of CCDC67. CCDC67 protein was localized to the cell membrane by immunocytochemistry. Stable transfection of a CCDC67 gene in one gastric cancer cell line inhibited adhesion-dependent and -independent colony formation, and CCDC67 expression suppressed tumorigenesis in nude mice. We suggest that CCDC67 is a putative tumor suppressor gene that is silenced in gastric cancers by promoter CpG methylation and that it may play an important role in cell signaling and migration related to tumorigenesis.
在这项研究中，通过限制性景观基因组扫描发现卷曲螺旋结构域蛋白 67（CCDC67）的启动子在胃癌细胞系和原发性胃癌肿瘤中经常发生甲基化。此外，在测试的 72.7%的胃癌细胞系中，CCDC67 的表达被下调。在大多数情况下，基因下调与 CCDC67 启动子中的 CpG 高甲基化有关。用 5-氮杂-2'-脱氧胞苷和/或曲古抑菌素 A 处理可恢复下调细胞系中的 CCDC67 表达。对 150 对配对的原发性胃癌样本进行焦磷酸测序分析显示，与配对的相邻正常组织相比，测试的肿瘤中启动子 CpG 甲基化增加了 74%，并且这种高甲基化与 CCDC67 的下调显著相关。免疫细胞化学显示 CCDC67 蛋白定位于细胞膜。在一个胃癌细胞系中稳定转染 CCDC67 基因可抑制黏附依赖性和非依赖性集落形成，并且 CCDC67 表达可抑制裸鼠的肿瘤发生。我们认为 CCDC67 是一个假定的肿瘤抑制基因，其启动子 CpG 甲基化导致胃癌中沉默，并且它可能在与肿瘤发生相关的细胞信号转导和迁移中发挥重要作用。
