[In vitro study on transduction of human O(6)-methylguanine-DNA-methyltransferase cDNA into human umbilical cord blood CD34(+) cells]

Abstract

Objective: To explore human umbilical cord blood hematopoietic progenitor cells transduced with human O(6)-methylguanine-DNA-methyltransferase (MGMT) gene increase resistance to 1,3-Bis(2-Chloroethyl)-1-Nitrosourea(BCNU).

Methods: The present authors obtained a full length cDNA fragment encoding the human MGMT from a patient with cholelithiasis liver tissue by RT-PCR method and confirmed by DNA sequencing. The fragment was cloned into pGEM-T vector and further subcloned into G1Na retrovirus vector. Then the G1Na-MGMT was transfected into the packaging cell lines GP+E86 and PA317 by LipofectAMINE method; using the medium containing BCNU for cloning selection and ping-ponging supernatant infection between ecotropic producer clone and amphotropic producer clone, the authors obtained high titer amphotropic PA317 producer clone with the highest titer up to 1.6x10(6) CFU/ml. Cord blood CD34(+) cell were transfected repeatedly with supernatant of retrovirus containing human MGMT cDNA under stimulation of hemopoietic growth factors.

Results: PCR, RT-PCR, Southern blot, Northern blot, Western blot and MTT analyses showed that MGMT gene had been integrated into the genomic DNA of cord blood CD34(+) cells and expressed efficiently in the transfected cells. The transgene recipient cells conferred 4 folds stronger resistance to BCNU than that of the non-transduced.

Conclusion: The retrovirus vector-mediated transfer of MGMT drug resistance gene into human cord blood CD34(+) cells and expression could confer the resistance of transgene cells to BCNU toxicity.