人胃癌IFN-γ-STAT1通路的作用及其机制

Role of IFN-γ-STAT1 pathway in human gastric adenocarcinoma

目的:分析人胃癌组织和胃癌SGC7901细胞中STAT1、Caspase-7及p21waf的表达关系,并探讨胃癌中IFN-γ-STAT1分子通路特点.方法:人胃癌组织免疫组织化学染色,IFN-γ及STAT1反义寡核苷酸处理SGC7901细胞.免疫细胞化学、RT-PCR及图像分析的方法检测mRNA和蛋白水平变化,应用Hoechest33258观察细胞凋亡.结果:人胃癌组织Caspase-7与STAT1和p21waf正相关(r=0.32,0.22,均P<0.05);SGC7901细胞经IFN-γ处理后,STAT1、Caspase-7和p21wafmRNA和蛋白表达明显上升(P<0.05).经IFN-和不同浓度STAT1反义寡核苷酸联合处理后,STAT1mRNA和蛋白表达较IFN-γ单独处理明显下降,有浓度依赖性(P<0.05).Caspase-7和P21waf蛋白表达较IFN-γ单独处理明显下降,有浓度依赖性(P<0.05),但是mRNA表达量则随着STAT1反义寡核苷酸浓度变化,出现Caspase-7先下降后上升,p21waf先上升后下降的变化.经IFN-γ和STAT1反义寡核苷酸处理后细胞无明显凋亡.结论:人胃癌组织和胃癌细胞系SGC7901中存在IFN-γ-STAT1通路,且可上调Caspase-7和p21waf的表达,但无明显凋亡调控作用;胃癌IFN-γ-STAT1分子通路的下游分子在mRNA水平和蛋白水平表达变化不一致.

AIM： To investigate relationships among STAT1, Caspase-7 and p21waf in gastric adenocarcinoma tissue and gastric adenocarcinoma cell SGC7901, and to shed light on features of IFN-γ-STAT1 pathway in gastric adenocarcinoma. METHODS： Gastric adenocarcinoma tissue was tested by immunohistochemical method. SGC7901 cell was treated with IFN-γ and STAT1 antisense oligonucleotides, and mRNA and protein expression was detected using RT-PCR, immunocytochemistry and image analysis methods. Apoptosis was determined by Hoechest 33258.RESULTS： Caspase-7 was positive correlation with STAT1 and p21waf （r = 0.32, 0.22, both P 〈 0.05） in gastric adenocarcinoma tissue. IFN-γ promoted mRNA and protein expression of STAT1, Caspase-7 and p21waf was up-regulated in SGC7901 cell （P 〈 0.05）. After treatment with IFN-γ along with varied concentrations of STAT1 antisense oligonucleotides, significantly lower STAT1 mRNA and protein expression was observed than IFN-γ used alone in SGC7901 cells, which showed a concentration-dependent manner （P 〈 0.05）; significantly lower Caspase-7 and P21waf protein expression was observed than IFN-γ used alone in SGC7901 cell in a concentration-dependent manner （P 〈 0.05）. However, mRNA expression of Caspase-7 was down-regulated first and then up-regulated, while mRNA expression of p21waf was up-regulated first and then down-regulated. CONCLUSION： There is a IFN-γ-STAT1 pathway in gastric adenocarcinoma tissue and SGC7901 cell line. IFN-γ-STAT1 could up-regulate the expression of Caspase-7 and p21waf in gastric adenocarcinoma, but could not induce apoptosis. The downstream molecular of IFN-γ- STAT1 pathway has different expression features in mRNA and protein expression level in gastric adenocarcinoma.