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背景与目的:人核糖核酸酶抑制因子(ribonucleaseinhibitor,RI)RI能有效抑制血管生成因子诱导的血管形成及某些可移植性实体瘤在动物体内的生长。然而,RI抗肿瘤的分子机制还未完全阐明。许多抑癌基因通过启动子区域异常的甲基化而使表达缺失,去甲基化抑制能使其表达恢复。为了进一步了解RI的功能以及探讨RI与肿瘤发生的关系,本实验拟研究甲基化抑制剂5-aza-2’-deoxycytidine(5-Aza-CdR)对肿瘤细胞中RI表达的影响。方法:用5-Aza-CdR作用人乳腺癌细胞系MCF-7、人胃癌细胞系BGC-823、人的前列腺癌细胞系DU-145和人结肠癌细胞系HT-29。通过RT-PCR,蛋白免疫印迹法(Westernblot),免疫荧光(immunofluorescence)和免疫细胞化学(immunocytochemistry)技术分析RI基因的表达。结果:与对照组比较,5-Aza-CdR能显著提高RI基因在MCF-7、BGC-823和DU-145细胞中的表达,RT-PCR检测结果分别为37.2%、46.0%和32.4%,Westernblot检测结果分别为26.4%、20.9%和24.4%(P<0.01);但对HT-29细胞没有明显的影响。结论:RI基因可能与胃癌、前列腺癌和乳腺癌的发生有关。
BACKGROUND & OBJECTIVE: RI of human ribonuclease inhibitor (RI) can effectively inhibit angiogenic factor-induced angiogenesis and the growth of some transplantable solid tumors in animals. However, the molecular mechanism of RI antitumor is not fully elucidated. Many tumor suppressor genes through the promoter region of the abnormal methylation and the lack of expression, demethylation can make its expression restored. In order to further understand the function of RI and explore the relationship between RI and tumorigenesis, this study was to investigate the effect of methylation inhibitor 5-aza-2’-deoxycytidine (5-Aza-CdR) on RI expression in tumor cells. Methods: Human breast cancer cell line MCF-7, human gastric cancer cell line BGC-823, human prostate cancer cell line DU-145 and human colon cancer cell line HT-29 were treated with 5-Aza-CdR. RI gene expression was analyzed by RT-PCR, Western blotting, immunofluorescence and immunocytochemistry techniques. Results: Compared with the control group, 5-Aza-CdR significantly increased the expression of RI gene in MCF-7, BGC-823 and DU-145 cells. The results of RT-PCR were 37.2%, 46.0% and 32.4% Western blot results were 26.4%, 20.9% and 24.4%, respectively (P <0.01), but had no significant effect on HT-29 cells. Conclusion: RI gene may be related to the occurrence of gastric cancer, prostate cancer and breast cancer.