Objective： The aim of the study was to construct a stable strain of recombined attenuated Salmonella typhimurium expressing NK4 gene, and observe the effect of the strain on the metastatic potentiality of HepG2 cells...Objective： The aim of the study was to construct a stable strain of recombined attenuated Salmonella typhimurium expressing NK4 gene, and observe the effect of the strain on the metastatic potentiality of HepG2 cells. Methods： The NK4 cDNA was isolated from PCAGGS/hNK4 plasmid by PCR, and subcloned into eukaryotic expression vector pcDNA4. The recombinant plasmid was electro-transferred into attenuated Salmonella typhimurium Ty21a to obtain the recombinant strain encoding NK4 gene （TPN）. Simultaneously, the recombinant attenuated Salmonella typhimurium carrying GFP gene （TPG） was also constructed. After the TPG and TPN were transferred into HepG2 cells, the transfection rate and the expression level of NK4 protein were detected by flow cytometry and ELISA, and the effects of expression product on the proliferation and migration of HepG2 and angiogenesis were observed. Results： The TPN and TPG were successfully constructed. Fortyeight hours after transfection with TPG, the infection rate was 82.58% ± 1.74%, and the expression level of NK4 protein in supernatant was （181.5 ± 11.7） ng/6 × 10^5 cells. The supematant had obviously depressant effect on the proliferative activity of HepG2 cells （P 〈 0.05）, and could obviously restrain the hepatocyte growth factor-mediated migration of tumor cells （P 〈 0.01）. The inhibitory effect of the expression product on the tumor angiopoiesis was obviously observed （P 〈 0.05）, without a dosage-effect relation. Conclusion： The TPN could effectively transfer tumor cells in vitro and express interest NK4 protein. The expression product could effectively inhibit the proliferation and migration of hepatocellular carcinoma cells and the tumor angiopoiesis.展开更多
目的:探讨MHC-Ⅰ类链相关分子A(MHC class I chain-related molecule A,MICA)多态性与乳腺癌细胞对NK细胞杀伤敏感性的关系。方法:测序分析乳腺癌细胞系MCF-7、MDA-MB-231、MDA-MB-435S和SK-BR-3的MICA等位基因,用Western blotting和流...目的:探讨MHC-Ⅰ类链相关分子A(MHC class I chain-related molecule A,MICA)多态性与乳腺癌细胞对NK细胞杀伤敏感性的关系。方法:测序分析乳腺癌细胞系MCF-7、MDA-MB-231、MDA-MB-435S和SK-BR-3的MICA等位基因,用Western blotting和流式细胞术检测MICA重组表达载体转染293T细胞(分别命名为p MCFA5.1、p MCFA4、p231A5R、p231A9和p435A5P)MICA蛋白的表达水平,用LDH法检测NK细胞对转染MICA的293T细胞的杀伤活性,酶联免疫斑点法检测NK细胞穿孔素、颗粒酶B分泌水平。结果:MCF-7细胞表达MICA*008/A5.1和MICA*001/A4,MDA-MB-231和SK-BR-3细胞均表达MICA*019/A5和MICA*002/A9,MDA-MB-435S细胞表达MICA*010/A5。转染MICA后,p MCFA5.1组293T细胞MICA蛋白的表达水平最低(P<0.05),p435A5P组次之(P<0.05),p MCFA4组、p231A5R组和p231A9组表达水平较高(均P<0.05)。NK细胞对转染MICA的293T细胞杀伤活性及穿孔素、颗粒酶B分泌:p435A5P组对NK细胞杀伤的敏感性最低(P<0.05),穿孔素、颗粒酶B分泌水平最低(均P<0.05);p MCFA5.1、p MCFA4、p231A5R和p231A9各组之间比较差异无统计学意义(P>0.05)。结论:MICA基因多态性与乳腺癌细胞对NK细胞杀伤的敏感性密切相关。展开更多
基金Supported by a grant from the National Natural Science Foundation of China (No.30772572)two research grants from Postdoctors in China (No.20060390192,200801243)+1 种基金a grant from the Natural Science Foundation of Gansu Province (No.0803RJZA061)a research grant for science from Gansu Provincial Sci. & Tech. Department (No.0708NKCA128)
文摘Objective： The aim of the study was to construct a stable strain of recombined attenuated Salmonella typhimurium expressing NK4 gene, and observe the effect of the strain on the metastatic potentiality of HepG2 cells. Methods： The NK4 cDNA was isolated from PCAGGS/hNK4 plasmid by PCR, and subcloned into eukaryotic expression vector pcDNA4. The recombinant plasmid was electro-transferred into attenuated Salmonella typhimurium Ty21a to obtain the recombinant strain encoding NK4 gene （TPN）. Simultaneously, the recombinant attenuated Salmonella typhimurium carrying GFP gene （TPG） was also constructed. After the TPG and TPN were transferred into HepG2 cells, the transfection rate and the expression level of NK4 protein were detected by flow cytometry and ELISA, and the effects of expression product on the proliferation and migration of HepG2 and angiogenesis were observed. Results： The TPN and TPG were successfully constructed. Fortyeight hours after transfection with TPG, the infection rate was 82.58% ± 1.74%, and the expression level of NK4 protein in supernatant was （181.5 ± 11.7） ng/6 × 10^5 cells. The supematant had obviously depressant effect on the proliferative activity of HepG2 cells （P 〈 0.05）, and could obviously restrain the hepatocyte growth factor-mediated migration of tumor cells （P 〈 0.01）. The inhibitory effect of the expression product on the tumor angiopoiesis was obviously observed （P 〈 0.05）, without a dosage-effect relation. Conclusion： The TPN could effectively transfer tumor cells in vitro and express interest NK4 protein. The expression product could effectively inhibit the proliferation and migration of hepatocellular carcinoma cells and the tumor angiopoiesis.
