Retrovirus-mediated transfer of the human O 6-Methylguanine-DNA methyltransferase gene into a murine hematopoietic stem cell line and resistance to the toxic effects of certain alkylating agents

• Published in: Biochemical pharmacology Vol. 51; no. 9; pp. 1221 - 1228
• Main Authors: Gang, Wang, Weiss, Clifford, Sheng, Peihua, Bresnick, Edward
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 03-05-1996
• Subjects: alkylating agents; DNA repair; drug resistance; gene transfer; methylation; MGMT; retrovirus; retrovirus; alkylating agents; gene transfer; MGMT; O 6-BG; hGH; DTIC; CNU; DNA repair; DMEM; CFU; MNU; G418; methylation; FBS; BCNU; TK; drug resistance; MNNG; PCR
• ISSN: 0006-2952; 1873-2968
• DOI: 10.1016/0006-2952(96)00077-9

O
6-Methylguanine-DNA methyltransferase (MGMT) is an important DNA repair protein that plays a key role in cancer chemotherapy by alkylating agents such as carmustine (BCNU) and Dacarbazine (DTIC). Therapy by BCNU and DTIC is reduced by dose-limiting hematological toxicity as a result of low MGMT repair activity in bone marrow cells. In this study, we have constructed a Moloney murine leukemia virus retroviral vector containing the human
mgmt gene. High-titer retrovirus producer cell lines have been generated. Retroviral-mediated transfer of the human
mgmt gene into murine multi-potent hematopoietic stem cells, FDCP-1, resulted in the expression of a high level of MGMT activity. In comparison with the control cells that were transduced with the parent vector, the MGMT-expressing clones were considerably more resistant to the cytotoxicity of the methylating agents, such as
N-methyl-
N′-nitro-
N-nitrosoguanidine,
N-nitroso-
N-methylurea, and temozolomide, as well as the chloroethylating agents 1-(2-chloroethyl)-1-nitrosourea and BCNU. The protection provided by MGMT could be eliminated by the MGMT inactivator O
6-benzylguanine. Thus, the principal lethal lesions produced by these alkylating agents in the murine hematopoietic stem cells and the MGMT deficiency in these cells can be complemented by retroviral-mediated gene transduction.