Effect of mutated IκBα transfection on multidrug resistance in hilar cholangiocarcinoma cell lines

AIM: To explore the expression effect of mutated I kappa B alpha transfection on multidrug resistance gene (MDR-1) in hilar cholangiocarcinoma cells by inhibiting the activity of nuclear transcription factor-kappa B (NF-kappa B). METHODS: We used the mutated I kappa B alpha plasmid to transfect QBC(939)HCVC+ cells and QBC939 cells, and electrophoretic gel mobility shift assay (EMSA) to detect the binding activity of NF-kappa B DNA and the effect of the transfrecting mutated I kappa B alpha plasmid on multidrug resistance gene (MDR-1) in hilar cholangiocarcinoma cells and its expression protein (P-GP). RESULTS: Plasmid DNA was digested by restriction enzymes Xbal and Hand III, and its product after electrophoresis showed two bands with a big difference in molecular weight, with a size of 4.9 kb and 1.55 kb respectively, which indicated that the carrier was successfully constructed and digested with enzymes. The radioactivity accumulation of QBC(939)HCVC+ and QBC939 cells transfected with mutated I kappa B alpha plasmid was significantly lower than that of the control group not transfected with mutated I kappa B alpha plasmid. Double densimeter scanning showed that the relative signal density between the tansfection group and non-transfection group was significantly different, which proved that the mutated I kappa B alpha plasmid could inhibit the binding activity of NF-kappa B DNA in hilar cholangiocarcinoma cells. Compared to control group not transfected with m I kappa B alpha plasmid, the expression level of MDR-1mRNA in the QBC939 and QBC939HCVC+ cells transfected with mutated I kappa B alpha plasmid was lower. The expression intensity of P-GP protein in QBC939 and QBC939HCVC+ cells transfected with mutated I kappa B alpha was significantly lower than that of the control group not transfected with mutated I kappa B alpha plasmid. CONCLUSION: The mutated I kappa B alpha plasmid transfection can markedly reverse the multidrug resistance of hilar cholangiocarcinoma cells. Interruption of NF-kappa B activity may become a new target in gene therapy for hilar cholangiocarcinogenesic carcinoma. (C) 2005 The WJG Press and Elsevier Inc. All rights reserved.