Regulation of cellular response to cisplatin-induced DNA damage and DNA repair in cells overexpressing p185(erbB-2) is dependent on the ras signaling pathway.
We have examined the role of erbB-2 expression in the modulation of cellular toxicity to cisplatin. We have demonstrated that treatment of NIH3T3-erbB-2 cells, which overexpress the p185(erbB-2) product of the human erbB-2 gene, with a monoclonal antibody directed against the extracellular domain (TAb-250), results in enhanced cisplatin cytotoxicity. A similar enhancement was obtained when cells were exposed to herbimycin A and its analogue CP127 374, both of which inhibit tyrosine kinase activity. Using the host cell reactivation (HCR) of reporter gene expression from cisplatin-damaged plasmid and unscheduled DNA synthesis (UDS) following cisplatin treatment of cells, we have found that modulation of erbB-2 by TAb-250 was associated with inhibition of DNA repair. TAb-250 alone, under conditions which modulate DNA repair, slightly reduces the S-phase of the cell cycle, while cisplatin induced arrest at S and G2 phases. Combination of TAb-250 and cisplatin only slightly prevented cisplatin-induced S and G2 blocks. Since the ras pathway is one of the major signaling components coupled to erbB-2, we have examined the role of ras in DNA repair regulation. Transient expression of a ras dominant negative mutant, Asn-17-ras(H), prevents DNA repair modulation by TAb-250, suggesting that the erbB-2 receptor regulates DNA repair mechanism(s), at least in part, through ras-coupled pathway(s).
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Lady Davis Institute of the Sir Mortimer B Davis Jewish General Hospital, Department of Medicine, McGill University, Montreal, Canada.
Nie
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You
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Richard
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Langton-Webster
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BC
Alaoui-Jamali
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MA
D016475:3T3 Cells / Q000166:cytology / Q000502:physiology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000918:Antibody Specificity; D000970:Antineoplastic Agents / Q000633:toxicity*; D016227:Benzoquinones; D002453:Cell Cycle / Q000187:drug effects; D002945:Cisplatin / Q000633:toxicity*; D004249:DNA Damage; D004260:DNA Repair; D015536:Down-Regulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D047029:Lactams, Macrocyclic; D051379:Mice; D008807:Mice, Inbred BALB C; D009154:Mutation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011809:Quinones / Q000494:pharmacology; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis / Q000502:physiology*; D017828:Rifabutin / Q000031:analogs & derivatives; D015398:Signal Transduction / Q000502:physiology*; D018631:ras Proteins / Q000502:physiology*
D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D016227:Benzoquinones; D002945:Cisplatin; D004791:Enzyme Inhibitors; D047029:Lactams, Macrocyclic; D011505:Protein-Tyrosine Kinases; D011809:Quinones; D018719:Erb-b2 Receptor Tyrosine Kinases; D017828:Rifabutin; D018631:ras Proteins; C105955:CP 127374; C020754:herbimycin