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dc.contributor.authorChinnasamy, Nachimuthu
dc.contributor.authorRafferty, Joseph A
dc.contributor.authorHickson, Ian
dc.contributor.authorLashford, Linda S
dc.contributor.authorLonghurst, S J
dc.contributor.authorThatcher, Nick
dc.contributor.authorMargison, Geoffrey P
dc.contributor.authorDexter, T Michael
dc.contributor.authorFairbairn, Leslie J
dc.date.accessioned2010-02-12T16:29:55Z
dc.date.available2010-02-12T16:29:55Z
dc.date.issued1998-06
dc.identifier.citationChemoprotective gene transfer II: multilineage in vivo protection of haemopoiesis against the effects of an antitumour agent by expression of a mutant human O6-alkylguanine-DNA alkyltransferase. 1998, 5 (6):842-7 Gene Ther.en
dc.identifier.issn0969-7128
dc.identifier.pmid9747465
dc.identifier.doi10.1038/sj.gt.3300699
dc.identifier.urihttp://hdl.handle.net/10541/92044
dc.description.abstractMurine bone marrow cells were transduced ex vivo with a retrovirus encoding an O6-benzylguanine (O6-beG) insensitive, double mutant form of the human DNA repair protein O6-alkylguanine-DNA alkyltransferase (hATPA/GA). In animals reconstituted with the transduced bone marrow, about 50% of cells in the multipotent spleen colony-forming cells (CFU-S) and lineage restricted granulocyte-macrophage (GM-CFC) haemopoietic progenitor populations were found to be carrying the transgene and this correlated with the frequency of bone marrow cells and spleen colonies which stained positive for hATPA/GA by immunocyto-chemistry. Expression of hATPA/GA was associated with significant in vivo protection of both CFU-S (P = 0.001) and GM-CFC (P < 0.024) against the toxicity of the antitumour methylating agent, temozolomide, given in combination with O6-beG. Expression of hATPA/GA also led to a reduction in the frequency of combined O6-beG/temozolomide-induced micronuclei seen in polychromatic erythrocytes (P < 0.003). This study is the first to demonstrate in vivo protection of multipotent haemopoietic progenitors against the toxic and clastogenic effects of an O6-alkylating agent in the presence of O6-beG. It also represents the first report of reduced clastogenesis as a consequence of expression of an O6-beG-resistant ATase. In the accompanying article we report hATPA/GA-mediated resistance of human CD34+ haemopoietic progenitors to combined O6-beG/O6-alkylating agent toxicity. Together these two reports suggest that a gene therapy strategy whereby protection of normal haemopoietic tissue may be combined with O6-beG-mediated tumour sensitisation may be efficacious in achieving an increase in therapeutic index.
dc.language.isoenen
dc.subject.meshAnimals
dc.subject.meshAntineoplastic Agents, Alkylating
dc.subject.meshBone Marrow Cells
dc.subject.meshCell Survival
dc.subject.meshDacarbazine
dc.subject.meshGene Expression
dc.subject.meshGene Transfer Techniques
dc.subject.meshGenetic Vectors
dc.subject.meshMale
dc.subject.meshMice
dc.subject.meshMice, Inbred Strains
dc.subject.meshO(6)-Methylguanine-DNA Methyltransferase
dc.subject.meshPolymerase Chain Reaction
dc.subject.meshRetroviridae
dc.subject.meshSpleen
dc.subject.meshStem Cells
dc.titleChemoprotective gene transfer II: multilineage in vivo protection of haemopoiesis against the effects of an antitumour agent by expression of a mutant human O6-alkylguanine-DNA alkyltransferase.en
dc.typeArticleen
dc.contributor.departmentCRC Sections of Genome Damage and Repair, Paterson Institute for Cancer Research, Manchester, UK.en
dc.identifier.journalGene Therapyen
html.description.abstractMurine bone marrow cells were transduced ex vivo with a retrovirus encoding an O6-benzylguanine (O6-beG) insensitive, double mutant form of the human DNA repair protein O6-alkylguanine-DNA alkyltransferase (hATPA/GA). In animals reconstituted with the transduced bone marrow, about 50% of cells in the multipotent spleen colony-forming cells (CFU-S) and lineage restricted granulocyte-macrophage (GM-CFC) haemopoietic progenitor populations were found to be carrying the transgene and this correlated with the frequency of bone marrow cells and spleen colonies which stained positive for hATPA/GA by immunocyto-chemistry. Expression of hATPA/GA was associated with significant in vivo protection of both CFU-S (P = 0.001) and GM-CFC (P < 0.024) against the toxicity of the antitumour methylating agent, temozolomide, given in combination with O6-beG. Expression of hATPA/GA also led to a reduction in the frequency of combined O6-beG/temozolomide-induced micronuclei seen in polychromatic erythrocytes (P < 0.003). This study is the first to demonstrate in vivo protection of multipotent haemopoietic progenitors against the toxic and clastogenic effects of an O6-alkylating agent in the presence of O6-beG. It also represents the first report of reduced clastogenesis as a consequence of expression of an O6-beG-resistant ATase. In the accompanying article we report hATPA/GA-mediated resistance of human CD34+ haemopoietic progenitors to combined O6-beG/O6-alkylating agent toxicity. Together these two reports suggest that a gene therapy strategy whereby protection of normal haemopoietic tissue may be combined with O6-beG-mediated tumour sensitisation may be efficacious in achieving an increase in therapeutic index.


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