title: Downregulation of intracellular nm23-H1 prevents cisplatin-induced DNA damage in oesophageal cancer cells: possible association with Na(+), K(+)-ATPase.
abstract: Previously, we showed that expression of nm23-H1 is associated inversely with sensitivity to cisplatin in human oesophageal squamous cell carcinoma (OSCC). The present study was undertaken to investigate the association of nm23-H1 expression with cisplatin-induced DNA damage in OSCC using antisense nm23-H1 transfectants. YES-2/AS-12, an antisense nm23-H1-transfected OSCC cell line, showed significantly reduced expression of intracellular nm23-H1 protein compared with that in parental YES-2 cells and YES-2/Neo transfectants. Surface expression of nm23-H1 protein was not observed in any of the three cell lines. PCR analysis for DNA damage demonstrated that YES-2/AS-12 cells were more resistant to nuclear and mitochondrial DNA damage by cisplatin than were YES-2/Neo cells. In addition, mitochondrial membrane potentials and DNA fragmentation assays confirmed that YES-2/AS-12 was more resistant than YES-2/Neo to apoptosis induced by cisplatin. In contrast, YES-2/AS-12 was more sensitive to ouabain, a selective inhibitor of Na(+), K(+)-ATPase, than YES-2 and YES-2/Neo. Pre-treatment with ouabain resulted in no differences in cisplatin sensitivity between the three cell lines examined. Intracellular platinum level in YES-2/AS-12 was significantly lower than that in YES-2 and YES-2/Neo following incubation with cisplatin, whereas ouabain pre-treatment resulted in no differences in intracellular platinum accumulations between the three cell lines. Our data support the conclusion that reduced expression of intracellular nm23-H1 in OSCC cells is associated with cisplatin resistance via the prevention of both nuclear and mitochondrial DNA damage and suggest that it may be related to Na(+), K(+)-ATPase activity, which is responsible for intracellular cisplatin accumulation.
authors.affiliation: Department of Bioregulatory Function, Department of Surgery II, Yamaguchi University School of Medicine, 1-1-1 Minami-kogushi, Ube, Yamaguchi, Japan.
authors.forename: N
authors.initials: N
authors.lastname: lizuka
authors.forename: K
authors.initials: K
authors.lastname: Miyamoto
authors.forename: A
authors.initials: A
authors.lastname: Tangoku
authors.forename: H
authors.initials: H
authors.lastname: Hayashi
authors.forename: S
authors.initials: S
authors.lastname: Hazama
authors.forename: S
authors.initials: S
authors.lastname: Yoshino
authors.forename: K
authors.initials: K
authors.lastname: Yoshimura
authors.forename: K
authors.initials: K
authors.lastname: Hirose
authors.forename: H
authors.initials: H
authors.lastname: Yoshida
authors.forename: M
authors.initials: M
authors.lastname: Oka
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology*; D004247:DNA / Q000187:drug effects / Q000235:genetics; D004249:DNA Damage; D053938:DNA Fragmentation / Q000187:drug effects; D016373:DNA, Antisense / Q000235:genetics; D004272:DNA, Mitochondrial / Q000187:drug effects / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D019008:Drug Resistance, Neoplasm; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004938:Esophageal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D006801:Humans; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D054778:NM23 Nucleoside Diphosphate Kinases; D009701:Nucleoside-Diphosphate Kinase; D010042:Ouabain / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D016373:DNA, Antisense; D004272:DNA, Mitochondrial; D004791:Enzyme Inhibitors; D054778:NM23 Nucleoside Diphosphate Kinases; D014157:Transcription Factors; D010042:Ouabain; D004247:DNA; C517938:NME1 protein, human; D009701:Nucleoside-Diphosphate Kinase; D020559:Monomeric GTP-Binding Proteins; D000254:Sodium-Potassium-Exchanging ATPase; D002945:Cisplatin