O6 -methylguanine- DNA- methyltransferase (MGMT ) plays a very important role in the cellular resis- tance to nitrosoureas drugs. Inhibition of MGMT might be a useful approach in tumor chemotherapy. In this study, the...O6 -methylguanine- DNA- methyltransferase (MGMT ) plays a very important role in the cellular resis- tance to nitrosoureas drugs. Inhibition of MGMT might be a useful approach in tumor chemotherapy. In this study, the depletion of MGMT activity by retroviral-mediated antisense RNA transfection were reported. Three retroviral vectors expressing MGMT antisense RNA were constructed and transfected into HeLa S3 cells. The difference of MGMT mRNA, MGMT activity as well as cellular resistance to ACNU before and after transfection were observed. It was found that antisense RNA targeting 5’region and whole length of MGMT mRNA could partially deplete MGMT activity and enhance killing effects of ACNU. However, 3’ region antisense RNA had no effect on MGMT modulation.展开更多
Objective To explore the strategies which reduce the amount of xenoantigen Galα1, 3 Gal. Methods Human α-galactosidase gene and α1,2-fucosyltransferase gene were transferred into cul-tured porcine vascular endothel...Objective To explore the strategies which reduce the amount of xenoantigen Galα1, 3 Gal. Methods Human α-galactosidase gene and α1,2-fucosyltransferase gene were transferred into cul-tured porcine vascular endothelial cells PEDSV.15 and human α-galactosidase transgenic mice were produced. The Galα1,3Gal on the cell surface and susceptibility of cells to human antibody-mediated lysis were analyzed. Results Human α-galactosidase gene alone reduced 78% of Galα1,3Gal on PEDSV.15 cell surface while human α-galactosidase combined with α1,2-fucosyltransferase genes removed Galα1,3Gal completely. Decrease of Galα1,3Gal could reduce susceptibility of cells to human antibody-mediated lysis, especially during co-expression of α-galactosidase gene and α1,2-fucosyltransferase gene. RT-PCR indicated positive human α-galactosidase gene expression in all organs of positive human α-galacto-sidase transgenic F1 mice including heart, liver, kidney, lung, and spleen, the amount of Galα1,3Gal antigens on which was reduced largely. 58% of spleen cells from F1 mice were destroyed by comp-lement-mediated lysis compared with 24% of those from normal mice. Conclusions Human α-galactosidase gene and α1,2-fucosyltransferase gene effectively reduce the expression of Galα1,3Gal antigens on endothelial cell surface and confers resistance to human serum-mediated cytolysis. The expression of human α-galactosidase in mice can also eliminate the Galα1,3Gal antigens in most tissues and decrease the susceptibility of spleen cells to human serum-mediated cytolysis.展开更多
基金This project is supported by National Foundation of Natural sciences of China.
文摘O6 -methylguanine- DNA- methyltransferase (MGMT ) plays a very important role in the cellular resis- tance to nitrosoureas drugs. Inhibition of MGMT might be a useful approach in tumor chemotherapy. In this study, the depletion of MGMT activity by retroviral-mediated antisense RNA transfection were reported. Three retroviral vectors expressing MGMT antisense RNA were constructed and transfected into HeLa S3 cells. The difference of MGMT mRNA, MGMT activity as well as cellular resistance to ACNU before and after transfection were observed. It was found that antisense RNA targeting 5’region and whole length of MGMT mRNA could partially deplete MGMT activity and enhance killing effects of ACNU. However, 3’ region antisense RNA had no effect on MGMT modulation.
文摘Objective To explore the strategies which reduce the amount of xenoantigen Galα1, 3 Gal. Methods Human α-galactosidase gene and α1,2-fucosyltransferase gene were transferred into cul-tured porcine vascular endothelial cells PEDSV.15 and human α-galactosidase transgenic mice were produced. The Galα1,3Gal on the cell surface and susceptibility of cells to human antibody-mediated lysis were analyzed. Results Human α-galactosidase gene alone reduced 78% of Galα1,3Gal on PEDSV.15 cell surface while human α-galactosidase combined with α1,2-fucosyltransferase genes removed Galα1,3Gal completely. Decrease of Galα1,3Gal could reduce susceptibility of cells to human antibody-mediated lysis, especially during co-expression of α-galactosidase gene and α1,2-fucosyltransferase gene. RT-PCR indicated positive human α-galactosidase gene expression in all organs of positive human α-galacto-sidase transgenic F1 mice including heart, liver, kidney, lung, and spleen, the amount of Galα1,3Gal antigens on which was reduced largely. 58% of spleen cells from F1 mice were destroyed by comp-lement-mediated lysis compared with 24% of those from normal mice. Conclusions Human α-galactosidase gene and α1,2-fucosyltransferase gene effectively reduce the expression of Galα1,3Gal antigens on endothelial cell surface and confers resistance to human serum-mediated cytolysis. The expression of human α-galactosidase in mice can also eliminate the Galα1,3Gal antigens in most tissues and decrease the susceptibility of spleen cells to human serum-mediated cytolysis.
