[Internal Ribosomal Entry Site-Mediated Expression of Human Multidrug Resistance 1 Gene in Human CD34(+) Cells]

In order to reach the purpose of co-transferring double drug resistance genes into human CD34(+) progenitor cells to broaden the spectrum of drug resistance, the expression efficiency of human multidrug resistance 1 (MDR1) gene mediated by the internal ribosomal entry site (IRES) was investigated. Two retroviral vectors were transferred into packaging cells. One is pSF-DIM containing double drug resistance genes, in which the translation of MDR1 gene was controlled under an IRES from encephalomyocarditis virus. The other is pSF-MDR1 which only contains MDR1 gene controlled under the same promoter of pSF-DIM. The amphotropic retroviral packaging cells PA317/pSF-DIM and PA317/pSF-MDR1 were obtained with titer of 8 x 10(4) and 1.3 x 10(5) cfu/ml respectively. Human cord blood CD34(+) cells were transduced by supernatant infection. Expression of P-gp was detected by flow cytometry. Compared with the untransduced group, the expression of P-gp in pSF-DIM transduced group and pSF-MDR1 transduced group was elevated 10.92% and 28.82% respectively. However, the expression of P-gp in pSF-MDR1 transduced group was higher than that in pSF-DIM transduced group. The result suggests that MDR1 gene can express in the human progenitor cells under control of IRES. It laid the foundation of subsequence research. The reason on the difference in MDR1 gene expression efficiency between pSF-MDR1 transduced group and pSF-DIM transduced group need further research.