ABSTRACT
Objective:To investigate the inhibitory effect of in vivo non-targeting transfection of recombinant fibronectin polypeptide CH50 against tumors and to study the related mechanisms.Methods:After inoculated with tumor cells, BALB/c mice were injected with CH50 plasmids,control plasmids,and normal saline separately.The growth of the tumor was observed;the expression of genes (such as B7-1,B7-H1 etc.) in tumor tissues was detected by RT-PCR;and the count of T lymphocytes in local tumor tissues was analyzed by flow cytometry.Results:The tumor growth was obviously suppressed by in vivo CH50 expression.The expression of genes (B7-1 and B7-H1) was up-regulated along with the growth of tumor.CH50 increased the ratios of B7-1/B7-H1 and B7-1/B7-DC and suppressed the up-regulation of IL-10 and TGF-?genes.The direct action of CH50 on H22 cells resulted in the down-regulatoin of TGF-?gene.The count of T lymphoeytes in tumor tissues of CH50 treatment group was significantly higher than that in other groups.Conclusion:Ex- pression of CH50 by non-targeting transfection can effectively inhibit the growth of tumor;the regulation of the immuno- regulatory genes in tumor mieroenvironment is an important part of the treatment mechanism of CH50.