title: Synergistic effects of adenovirus expressing wild-type p53 on chemosensitivity of non-small cell lung cancer cells.
abstract: The infection of recombinant adenovirus expressing wild-type p53 (Ad-p53) to lung cancer cells that harbor mutant p53 genes improves their response to cis-diamminedichloroplatinum(II). In this study, we tested whether this improvement in response is also seen in wild-type p53 (wt-p53)-containing cancer cells and whether this phenomenon is universal with other commonly used chemotherapeutic agents, including etoposide, 7-ethyl-10-hydrocycamptothecin, paclitaxel, and docetaxel. Using a panel of 7 non-small cell lung cancer cell lines with wild-type (2) or abnormal (2 null, 3 point-mutated) p53, we examined in vitro cytotoxicity using a tetrazolium-based colorimetric assay (3-(4,5-diethylthiazoyl-2-yl)-2,5-diphenyltetrazolium bromide assay) and analyzed the combined effects of Ad-p53 and chemotherapeutic agents using the isobologram method. Ad-p53 and DNA-damaging agents (cis-diamminedichloroplatinum(II), etoposide, and 7-ethyl-10-hydrocycamptothecin) showed synergistic effects in six of seven cell lines but additive effects against a p53-mutated cell line. In contrast, Ad-p53 showed additive effects with the antitubulin agents (paclitaxel and docetaxel) in all four of the cell lines tested. Furthermore, we examined this synergistic interaction between Ad-p53 and DNA-damaging agents by flow cytometric analysis and DNA fragmentation analysis. Both analyses revealed that a sublethal dose of Ad-p53 augmented the apoptotic response induced by DNA-damaging agents in six of seven cell lines. Our results suggest that Ad-p53 may synergistically enhance the chemosensitivity of the majority of non-small cell lung cancers to DNA-damaging agents due to augmentation of apoptosis.
authors.affiliation: First Department of Internal Medicine, Nagoya University School of Medicine, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Horio
authors.forename: Y
authors.initials: Y
authors.lastname: Hasegawa
authors.forename: Y
authors.initials: Y
authors.lastname: Sekido
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
authors.forename: J A
authors.initials: JA
authors.lastname: Roth
authors.forename: K
authors.initials: K
authors.lastname: Shimokata
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D002289:Carcinoma, Non-Small-Cell Lung; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000633:toxicity*; D016158:Genes, p53; D006801:Humans; D008175:Lung Neoplasms; D016296:Mutagenesis; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000502:physiology*
chemical_list: D016159:Tumor Suppressor Protein p53; D002945:Cisplatin