Objective: To explore the feasibility of cotransferring human mdr-1 gene and DHFR gene into human CD(34)(+) progenitor cells to broaden the spectrum of drug resistance and improve the tolerance of myelosuppression following combination chemotherapy.
Methods: The recombinant retroviral vector pSF-DIM containing mdr-1 and DHFR (L22Y) gene was constructed by introducing IRES sequence into vector FMCF which enable highly efficient gene expression in early hematopoietic cells. The retrovirus titers were raised by repeated supernatant cross infection between the amphotropic and ectropic retroviral packaging cells. Human CD(34)(+) progenitor cells were transduced by supernatant infection. Expression of P-gp was detected by flow cytometry. Integration of the foreign drug resistance gene in CD(34)(+) cells was determined by PCR. Drug resistance was evaluated by CFU-GM assay.
Result: Integration of the two foreign drug resistance genes was detected in the CD(34)(+) cells after pSF-DIM transduction. Compared with the untransduced group, the expression of P-gp elevated by 10.98% after gene transduction and the CFU-GM yields were significantly increased at 48 nmol/L of MTX and 10 ng/ml or 12 ng/ml of taxol (P < 0.05).
Conclusion: The retroviral vector pSF-DIM can mediate mdr-1 and DHFR gene integration and co-expression in human hematopoietic progenitor cells so as to broaden the spectrum of drug resistance.