Hypermethylation and Clinicopathological Significance of RASAL1 Gene in Gastric Cancer
Hypermethylation and Clinicopathological Significance of RASAL1 Gene in Gastric Cancer
复制标题
DOI：
10.7314/apjcp.2013.14.11.6261
复制
发表时间：
2013-01-01
影响因子：
--
通讯作者：
Fan, Hong
中科院分区：
文献类型：
--
作者：
Chen, Hong;Pan, Ying;Fan, Hong
背景：最近的研究表明，RAS蛋白激活剂样1基因（RASAL1）在胃癌组织和细胞系中表达降低，表明其在胃癌的发生和发展中发挥作用。 RASAL1 表达减少可能导致癌细胞中 RAS 信号通路活性异常增加。然而，诱导 RASAL1 基因下调的确切机制仍不清楚。本研究旨在确定胃癌中RASAL1的甲基化状态和调控。材料和方法：利用甲基化特异性聚合酶链反应（MSP），评估了 40 例胃癌患者和配对的癌旁非癌组织中 RASAL1 启动子中 CpG 岛的甲基化状态，并分析了其临床病理意义。在用 DNA 甲基转移酶抑制剂 5-aza-2'-doexycytidine (5-Aza-CdR) 处理后，还测定了胃癌细胞系 MKN-28、SGC-790l、BGC-823 以及正常胃上皮细胞系 GES-1 中 RASAL1 的甲基化状态。通过 Pull-down 方法评估 RAS 活性 (GAS-GTP)，并通过蛋白质印迹法测定 RAS 信号通路下游分子 ERK1/2 的蛋白水平。结果：胃癌和配对的癌旁非癌组织中RASAL1启动子甲基化频率分别为70%（28/40）和30%（12/40）（P
Background: Recent studies have suggested that expression of the RAS protein activator like-1 gene (RASAL1) is decreased in gastric carcinoma tissues and cell lines, indicated a role in tumorigenesis and development of gastric cancer. Reduced expression of RASAL1 could result in aberrant increase of activity of RAS signaling pathways in cancer cells. However, the exact mechanism which induces down-regulation of the RASAL1 gene remains unclear. This study aimed to determine the methylation status and regulation of RASAL1 in gastric cancer. Materials and Methods: Using the methylation-specific polymerase chain reaction (MSP), the methylation status of CpG islands in the RASAL1 promoter in gastric cancers and paired adjacent non-cancerous tissues from 40 patients was assessed and its clinicopathological significance was analyzed. The methylation status of RASAL1 in gastric cancer lines MKN-28, SGC-790l, BGC-823, as well as in normal gastric epithelial cell line GES-1 was also determined after treatment with a DNA methyltransferase inhibitor, 5-aza-2'-doexycytidine (5-Aza-CdR). RAS activity (GAS-GTP) was assessed through a pull-down method, while protein levels of ERK1/2, a downstream molecule of RAS signaling pathways, were determined by Western blotting. Results: The frequencies of RASAL1 promoter methylation in gastric cancer and paired adjacent non-cancerous tissues were 70% (28/40) and 30% (12/40) respectively (P