Effects of DNA methylation on expression of tumor suppressor genes and proto-oncogene in human colon cancer cell lines
Effects of DNA methylation on expression of tumor suppressor genes and proto-oncogene in human colon cancer cell lines
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DNA甲基化对人结肠癌细胞系抑癌基因和原癌基因表达的影响
DOI：
10.3748/wjg.v9.i9.1976
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发表时间：
2003-09-01
影响因子：
4.3
通讯作者：
Yang, L
中科院分区：
文献类型：
--
作者：
Fang, JY;Lu, J;Yang, L
目的：方法：用不同浓度的DNA甲基转移酶抑制剂5-氮杂脱氧胞苷（5-aza-dC）处理HT-29、SW 1116和科洛-320三种人结肠癌细胞株，观察DNA甲基化对抑癌基因和原癌基因表达的影响。RT-PCR检测p167（INK 4A）、p21（WAF 1）、APC和c-myc基因的表达。结果：HT-29细胞中p16（INK 4A）和APC基因均呈弱阳性表达，而SW 1116和科洛-320细胞中p21（WAF 1）基因未表达。1 mumol/L5-aza-dC处理HT-29细胞后，p16（INK 4A）基因启动子甲基化水平显著降低，而10 mumol/L5-aza-dC处理后，p16（INK 4A）基因启动子甲基化水平显著降低，导致p16（INK 4A）基因转录上调。在SW 1116和科洛-320细胞株中，10 μ mol/L和5 μ mol/L5-aza-dC作用24 h后，p16（INK 4A）和APC mRNA表达均明显增强。结论：p16（INK 4A）和APC基因在3种人结肠癌细胞系中的表达受DNA甲基化的调控。
AIM: To investigate the effects of DNA methylation on the expression of tumor suppressor genes and proto-oncogene in human colon cancer cell lines.METHODS: Three colon cancer cell lines (HT-29, SW1116 and Colo-320) treated with different concentrations of DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine (5-aza-dC) were used to induce DNA demethylation. The expressions of p167(INK4A) p21(WAF1), APC and c-myc genes were observed by using RT-PCR. The methylation status of p16(INK4A) promoter in HT-29 cells was also determined by methylation-specific PCR (MSP).RESULTS: Weak expressions of p16(INK4A) and APC in the three colon cancer cells were detected, and p21(WAF1) expression was not found in SW1116 and Colo-320 cells before treatment. After treatment of 1 mumol/L but not 10 mumol/L of 5-aza-dC, the methylation level of p16(INK4A) gene promoter decreased significantly, and the hypomethylation led to the up-regulation of p16(INK4A) gene transcription in HT-29 cells. In the cell lines of SW1116 and Colo-320, p16(INK4A) and APC mRNA expressions were obviously enhanced after treatment of either 10 mumol/L or 5 mumol/L 5-aza-dC for 24 h. However, no evidence was found that methylation regulated the expression of p21(WAF1) and c-myc genes in human colon cancer cell lines.CONCLUSION: Expression of p16(INK4A) and APC genes is regulated by DNA methylation in three human colon cancer cell lines.