Cell-type-specific repression of the maspin gene is disrupted frequently by demethylation at the promoter region in gastric intestinal metaplasia and cancer cells
Cell-type-specific repression of the maspin gene is disrupted frequently by demethylation at the promoter region in gastric intestinal metaplasia and cancer cells
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DOI：
10.1016/s0002-9440(10)63549-3
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发表时间：
2003-11-01
影响因子：
6
通讯作者：
Masuda, T
中科院分区：
文献类型：
--
作者：
Akiyama, Y;Maesawa, C;Masuda, T
Maspin是一种丝氨酸蛋白酶抑制剂，最初被报道为乳腺癌和前列腺癌的肿瘤抑制基因。我们检查了四种胃癌细胞中maspin的表达和/或等位基因特异性甲基化状态。细胞，以及从50名胃癌患者获得的正常、化生和癌性上皮。三个胃癌细胞系表现出maspin过表达表现出低甲基化在两个等位基因或一个单倍体等位基因。只有一个细胞系（GCIY）是maspin阴性的，但用去甲基化剂5-氮杂-2 '-脱氧胞苷处理后maspin表达被重新激活。在50例胃癌和所有伴有肠上皮化生（M）的胃正常上皮（GNE）中，有40例（80%）观察到密集和弥漫的maspin免疫反应，但在不伴IM的GNE中未观察到。我们进一步分析了等位基因特异性甲基化状态的50例进行免疫组化的隐窝分离技术，然后亚硫酸氢盐基因组测序方法。没有IM的所有GNE的maspin基因启动子区域在两个等位基因上都是高甲基化的，而IM的那些经常代表了低甲基化状态的单倍体类型。在7个胃癌中的6个，其中隐窝分离是可能的，去甲基化频繁发生，并扩展到两个alletes。Maspin mRNA在有IM的GNE和癌性隐窝中扩增，但在无IM的GNE中未扩增。这些结果表明去甲基化。在maspin基因启动子处的突变破坏了GNE和胃癌中的细胞类型特异性基因抑制。
Maspin, a serine protease inhibitor, was originally reported as a tumor suppressor gene in breast and prostatic cancers. We examined maspin expression and/or the allele-specific methylation status in four gastric cancer cell. lines, as well as normal, metaplastic, and cancerous epithelia obtained from 50 gastric cancer patients. Three gastric cancer cell lines exhibiting maspin overexpression showed hypomethylation at either both alleles or a haploid allele. Only one cell line (GCIY) was maspin-negative but maspin expression was reactivated after treatment with a demethylating agent, 5-aza-2'-deoxycytidine. Dense and diffuse immunoreactivity for maspin was observed in 40 (80%) of 50 gastric cancers and all gastric normal epithelia (GNE) with intestinal metaplasia (M), but not in GNE without IM. We further analyzed the allele-specific methylation status in 10 of 50 cases subjected to immunohistochemistry by the crypt isolation technique followed by a bisulfite genome sequencing method. The maspin gene promoter region of all GNE without IM was hypermethylated on both alleles whereas those with IM frequently represented the haplold type of hypomethylation status. In six of seven gastric cancers in which crypt isolation was possible, demethylation frequently occurred and extended to both alletes. Maspin mRNA was amplified from GNE with IM and cancerous crypts but not from GNE without IM. These results suggest that demethylation. at the maspin gene promoter disrupts the cell-type-specific gene repression in both GNE and gastric cancer.