title: Hypersensitivity to DNA cross-linking agents associated with up-regulation of glucose-regulated stress protein GRP78.
abstract: We have shown previously that NAD/poly(ADP-ribose) polymerase-deficient cells that overexpress Mr 78,000 glucose-regulated stress protein (GRP78) are resistant to topoisomerase II inhibitors, such as etoposide, m-amsacrine, and doxorubicin. However, these cells have been found to be hypersensitive to DNA cross-linking agents, including melphalan, cisplatin, and 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). These observations prompted us to examine whether overexpression of GRP78 is associated with modulation of cytotoxicity of clinically useful DNA-cross-linking agents such as melphalan, BCNU, and cisplatin. We up-regulated GRP78 in V79 Chinese hamster cells by 2-5-fold using two independent approaches that include exposure to 6-aminonicotinamide, or 2-deoxyglucose. Subsequently, these GRP78-overexpressing cells were trypsinized, plated in regular medium without GRP78-inducing agents, and allowed a 5-h attachment time before being treated with melphalan, BCNU, or cisplatin for 1 h to determine clonogenic survivals. In addition, repair of DNA cross-links induced by those agents were determined by alkaline elution assay. Our results show that the GRP78-overexpressing V79 cells are hypersensitive to DNA cross-linking agents compared to the control V79 cells. Furthermore, repair of drug-induced DNA cross-links appears to be considerably slower in these cells relative to that found in control V79 cells. Thus, our results suggest that (a) up-regulation of GRP78 is associated with an impairment of DNA cross-link repair, (b) up-regulation of GRP78 is associated with potentiation of cytotoxicity induced by alkylating and platinating agents, and (c) up-regulation of GRP78 can be considered as a potentially useful tool to modulate the cytotoxicity of clinically useful alkylating and platinating agents.
authors.affiliation: Department of Medicine, and Cancer Research Center, Case Western Reserve University, Cleveland, Ohio 44106-4937, USA.
authors.forename: S
authors.initials: S
authors.lastname: Chatterjee
authors.forename: H
authors.initials: H
authors.lastname: Hirota
authors.forename: C A
authors.initials: CA
authors.lastname: Belfi
authors.forename: S J
authors.initials: SJ
authors.lastname: Berger
authors.forename: N A
authors.initials: NA
authors.lastname: Berger
mesh_terms: D015120:6-Aminonicotinamide / Q000494:pharmacology; D000818:Animals; D000963:Antimetabolites / Q000494:pharmacology; D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology*; D002330:Carmustine / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology; D006224:Cricetinae; D004260:DNA Repair; D004273:DNA, Neoplasm / Q000187:drug effects*; D003847:Deoxyglucose / Q000494:pharmacology; D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins / Q000378:metabolism*; D008558:Melphalan / Q000494:pharmacology; D018832:Molecular Chaperones / Q000378:metabolism*; D013723:Teratogens / Q000494:pharmacology; D015854:Up-Regulation
chemical_list: D000963:Antimetabolites; D018906:Antineoplastic Agents, Alkylating; D002352:Carrier Proteins; D004273:DNA, Neoplasm; D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D013723:Teratogens; D015120:6-Aminonicotinamide; D003847:Deoxyglucose; D002945:Cisplatin; D008558:Melphalan; D002330:Carmustine