Combination gene delivery of the cell cycle inhibitor p27 with thymidine kinase enhances prodrug cytotoxicity.
Cytoxicity induced by the herpesvirus thymidine kinase (TK) gene in combination with prodrugs is dependent on cell growth and leads to the elimination of genetically modified cells, thus limiting the duration of expression and efficacy of this treatment in vivo. Here, an effort was made to enhance TK/prodrug efficacy by coexpression of a cyclin-dependent kinase inhibitor (CKI), p27, to render cells resistant to TK/prodrug by inhibiting DNA synthesis. Expression of p27 by transfection substantially reduced cell cycle progression, and its activity was enhanced by mutations designed to stabilize the protein. Coexpression of p27 and TK or a p27/TK fusion protein led to greater prodrug cytotoxicity than that produced by TK alone in the Renca cell line, which is sensitive to bystander killing. Combination gene transfer of this CKI with TK therefore sustained the synthesis of TK by genetically modified cells to enhance the susceptibility of bystander cells to prodrug cytotoxicity and increased the efficacy of this gene transfer approach.
Departments of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0644, USA.
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Danthinne
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Aoki
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Kurachi
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GJ
Nabel
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Nabel
D001483:Base Sequence; D018797:Cell Cycle Proteins; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors*; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000378:metabolism; D016193:G1 Phase; D018014:Gene Transfer Techniques; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000008:administration & dosage / Q000096:biosynthesis / Q000235:genetics*; D009838:Oligodeoxyribonucleotides / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D011355:Prodrugs / Q000008:administration & dosage / Q000494:pharmacology*; D011506:Proteins; D016196:S Phase; D013937:Thymidine Kinase / Q000008:administration & dosage / Q000096:biosynthesis / Q000235:genetics*; D014162:Transfection; D025521:Tumor Suppressor Proteins
D018797:Cell Cycle Proteins; D004791:Enzyme Inhibitors; D008869:Microtubule-Associated Proteins; D009838:Oligodeoxyribonucleotides; D011355:Prodrugs; D011506:Proteins; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D013937:Thymidine Kinase; D018844:Cyclin-Dependent Kinases