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TNF临床应用毒副作用严重,其中主要的原因是某些肿瘤细胞表面表达的TNF受体(TNFR)量过少,而正常组织表达的TNFR量相对较多.因此,提高肿瘤细胞TNFR的表达水平有助于减少副作用,增强抗肿瘤效果.日本学者Isobe等人首先将人TNFR基因转染入人结肠癌细胞株TK.人TNFR分55Kd和57Kd两种,因此,他们首先分别将此两种TNFR基因插入到含Neo基因的逆转录病毒表达载体pLRNL中,然后利用上述载体分别转染包装细胞PA317,经G418抗性筛选及病毒效价测定得到高分泌病毒效价的PA317细胞株.人结肠癌细胞系TK本身几乎不表达TNFR,分别经携带55Kd或75KdTNFR基因的PA317病毒分泌上清感染,并经G418筛选及Northern印迹分析,分别得到表达55KdTNFR的TK克隆TK55和表达75KdTNFR的TK克隆TK75—1.TNF与TK55及TK75-1的结合试验证实TNF与TK55和TK75—1的特异性结合量增多;TNF杀伤试验说明TNF对TK55和TK75—1的杀伤作用显著高于TNF对TK的杀伤作用.Isobe的研究表明,TNFR基因转染入不表达TNFR的肿瘤细胞能增强TNF对该肿瘤细胞的杀伤作用.本研究还说明,细胞因子受体基因转染不表达该细胞因子受体的肿瘤细胞将是肿瘤细胞靶向的细胞因子基因治疗的新途径.
TNF clinical application of serious side effects, the main reason is that some tumor cell surface expression of TNF receptor (TNFR) amount is too small, but the amount of TNFR expressed in normal tissues is relatively more. Therefore, to increase tumor cell TNFR expression levels are Helps reduce side effects and enhance anti-tumor effects. Japanese scholar Isobe et al. first transfected human TNFR gene into human colon cancer cell line TK. Human TNFR was divided into 55Kd and 57Kd. Therefore, they firstly used the two TNFR genes respectively. Inserted into the retroviral expression vector pLRNL containing Neo gene, and then transfected with the packaging cell PA317 using the above vector, and the high-secretion virus titer PA317 cell line was obtained through G418 resistance screening and virus titer assay. The TK line almost did not express TNFR, and was infected with secretory supernatant of the PA317 virus carrying the 55Kd or 75KdTNFR gene respectively. The TK clone TK55 expressing 55KdTNFR and the TK clone TK75-1 expressing 75KdTNFR were obtained by G418 selection and Northern blot analysis, respectively. Binding of TNF to TK55 and TK75-1 demonstrated that the specific binding of TNF to TK55 and TK75-1 was increased. The TNF killing test showed that the killing effect of TNF on TK55 and TK75-1 was significantly higher than that of TNF. The killing effect of TK. Isobe’s research shows that transfection of TNFR gene into tumor cells that do not express TNFR can enhance the killing effect of TNF on the tumor cells. This study also shows that the cytokine receptor gene transfection does not express the cytokine. The receptor’s tumor cells will be a new approach for tumor cell-targeted cytokine gene therapy.