title: Establishment of a cisplatin-resistant gastric carcinoma cell line OCUM-2M/DDP.
abstract: A cis-diamminedichloroplatinum (CDDP)-resistant scirrhous gastric cancer cell line, OCUM-2M/DDP, was established by chronic exposure of cells of the parent scirrhous gastric cancer cell line, OCUM-2M, to CDDP at progressively increasing concentrations. The OCUM-2M/DDP cell line had an 11.3-fold higher level of resistance relative to its parent cell line as determined by a succinate dehydrogenase inhibition test. The biological and biochemical characteristics of the resistant and parent cell line were compared. There were differences in the modal chromosome number and DNA index, suggesting that some alterations of the DNA in the CDDP-resistant cells had occurred. Neither the parent nor resistant cell line expressed mdr-1 mRNA. After exposure to CDDP for 4 h, the intracellular platinum content of OCUM-2M cells was significantly higher than that of OCUM-2M/DDP cells (51.9 +/- 1.8 vs 16.4 plus 1.0 ng/mg protein, mean +/- SD, respectively). The GSH levels in OCUM-2M cells and OCUM-2M/DDP cells were 3.5 +/- 1.0 micrograms/mg protein and 16.8 +/- 1.2 micrograms/mg protein, respectively. These levels were also significantly different. These findings suggest that the possible mechanisms of acquired resistance to CDDP in OCUM-2M/DDP cells may be a decrease in intracellular CDDP accumulation and detoxication by GSH. This OCUM-2M/DDP cell line could be used in further investigations of the mechanism of CDDP resistance in gastric cancer.
authors.affiliation: First Department of Surgery, Osaka City University Medical School, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Nitta
authors.forename: Y S
authors.initials: YS
authors.lastname: Chung
authors.forename: B
authors.initials: B
authors.lastname: Nakata
authors.forename: M
authors.initials: M
authors.lastname: Yashiro
authors.forename: N
authors.initials: N
authors.lastname: Onoda
authors.forename: K
authors.initials: K
authors.lastname: Maeda
authors.forename: T
authors.initials: T
authors.lastname: Sawada
authors.forename: M
authors.initials: M
authors.lastname: Sowa
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D002945:Cisplatin / Q000493:pharmacokinetics / Q000494:pharmacology*; D004351:Drug Resistance; D005978:Glutathione / Q000032:analysis; D006801:Humans; D010984:Platinum / Q000032:analysis; D013274:Stomach Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D010984:Platinum; D005978:Glutathione; D002945:Cisplatin