Kramer BA, Lemckert FA, Alexander IE, Gunning PW, McCowage GB. Characterisation of a P140K mutantO6-methylguanine-DNA-methyltransferase (MGMT)-expressing transgenic mouse line with drug-selectable bone marrow.
J Gene Med 2006;
8:1071-85. [PMID:
16927363 DOI:
10.1002/jgm.937]
[Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND
Gene transfer of the P140K mutant of O6-methylguanine-DNA-methyltransferase (MGMT(P140K)) into hematopoietic stem cells (HSC) provides a mechanism for drug resistance and the selective expansion of gene-modified cells in vivo. Possible clinical applications for this strategy include chemoprotection to allow dose escalation of alkylating chemotherapy, or combining MGMT(P140K) expression with a therapeutic gene in the treatment of genetic diseases. Our aim is to use MGMT(P140K)-driven in vivo selection to develop allogeneic micro-transplantation protocols that rely on post-engraftment selection to overcome the requirement for highly toxic pre-transplant conditioning, and to establish and maintain predictable levels of donor/recipient chimerism.
METHODS
Using stably transfected murine embryonic stem (ES) cells, we have generated a C57BL/6 transgenic mouse line with expression of MGMT(P140K) within the hematopoietic compartment for use as a standard source of donor HSC in such models. Functional characterisation of transgene expression was carried out in chemotherapy-treated transgenic mice and in allogeneic recipients of transgenic HSC.
RESULTS
Expression of the transgene provided chemoprotection and allowed in vivo selection of MGMT(P140K)-expressing cells in transgenic mice after exposure to O6-benzylguanine (BG) and N,N'-bis(2-chloroethyl)-N-nitrosourea (BCNU). In an allogeneic transplant experiment in which transgenic HSC were engrafted into 129 strain recipients following low intensity conditioning (Busulfan, anti-CD8, anti-CD40Ligand), MGMT(P140K)-expressing cells could be selected using chemotherapy.
CONCLUSIONS
This MGMT(P140K) transgenic mouse line provides a useful source of drug-selectable donor cells for the development of non-myeloablative allogeneic transplant models in which variation in transplant conditioning elements can be investigated independently of gene transfer efficiency.
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