Expression of mouse metallothioneins-I genomic gene in CHO-dhfr- cells and its applications on medical therapy

Mouse metallothioneins-I genomic gene was inserted into pSV2-dhfr plasmid at the sites of EcoRI and the recombinant plasmid was transferred into CHO-dhfr- cells by DNA-calcium phosphate coprecitation method. Using western Blotting, RNA Hybridization, we could find the expression of MT-I at the level of 1.8 ??g/106 cells in D-22 clonal cells which were selected by DMEM selective medium more than 8 weeks. The D-22 cells were treated with cisplatin and the IC50 to cisplatin was 0.145 ??mol/L, being 3.1-fold resistance to cisplatin compared with the non-transfected cells - CHO-dhfr- cells (0.04 ??mol/L). These results provided the evidence of that Metallothionein may play an important role in protecting CHO cells from cytotoxicity of cisplatin. So increasing the synthesis of MT by the inducer such as BSN and blocking the synthesis of MT by the inhibitor such as proparglycine may be a potential way to treat some refractory carcinomas in chemotherapy.EI04481-4873