title: Increased expression of thioredoxin/adult T-cell leukemia-derived factor in cisplatin-resistant human cancer cell lines.
abstract: Thioredoxin (TRX) is a widely distributed Mr 13,000 protein with a redox-active dithiol/disulfide in the active site. The TRX system, consisting of TRX, TRX reductase, and NADPH, has an intracellular reducing capacity. Another reducing capacity, glutathione (GSH), can be associated with cis-diaminedichloroplatinum (cDDP) resistance. Therefore, we examined the involvement of TRX in cDDP resistance using two cell lines designated St/DDP and HT/DDP, which were established from the human gastric cancer cell line St-4 and the colon cancer cell line HT-29. St/DDP and HT/DDP were seven and five times as resistant to cDDP as their parental lines, and the expression of TRX in these variants was increased by 2.5- and 2-fold, respectively. The expression of TRX in the complete revertant cells of St/DDP was reduced as low as that in St-4 cells. TRX reductase activity was also increased in St/DDP and HT/DDP, suggesting that activation of the TRX system was associated with in vitro-acquired cDDP resistance. Because cDDP is the first-line drug against ovarian cancer, we examined the expression of TRX in 11 human ovarian cancer cell lines not treated with cDDP in vitro. Positive correlation between TRX expression and cDDP resistance was observed in these cell lines (r = 0.76, P = 0.007). This correlation was comparable to that between GSH content and cDDP resistance (r = 0.69, P = 0.019). These results suggest a possible involvement of TRX, as well as GSH, in cDDP resistance.
authors.affiliation: Laboratory of Biomedical Research, Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yamada
authors.forename: A
authors.initials: A
authors.lastname: Tomida
authors.forename: H
authors.initials: H
authors.lastname: Yoshikawa
authors.forename: Y
authors.initials: Y
authors.lastname: Taketani
authors.forename: T
authors.initials: T
authors.lastname: Tsuruo
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D002945:Cisplatin / Q000494:pharmacology*; D016207:Cytokines / Q000032:analysis*; D019008:Drug Resistance, Neoplasm; D005978:Glutathione / Q000032:analysis; D006801:Humans; D009363:Neoplasm Proteins / Q000032:analysis*; D009369:Neoplasms / Q000737:chemistry / Q000188:drug therapy*; D013880:Thioredoxin-Disulfide Reductase / Q000378:metabolism; D013879:Thioredoxins / Q000032:analysis*; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D016207:Cytokines; D009363:Neoplasm Proteins; C055533:adult T cell leukemia-derived factor; D013879:Thioredoxins; D013880:Thioredoxin-Disulfide Reductase; D005978:Glutathione; D002945:Cisplatin