title: Establishment of a daunorubicin-resistant cell line which shows multi-drug resistance by multifactorial mechanisms.
abstract: We established a daunorubicin (DNR)-resistant cell line derived from human leukemia cell line K562, (K562/D1-9), which also shows multidrug resistance (MDR). K562 cells were cultured with serially increasing concentrations up to 1.0 microM of DNR and then cloned by the limiting dilution method. K562/D1-9 cells were found to be 28 times more resistant to DNR than their its parent cells. Intracellular accumulation of DNR in K562/D1-9 was less than in the wild type, and P-glycoprotein (PGP) was overexpressed. Both DNR resistance and its intracellular accumulation were partially reversed by addition of verapamil to K562/D1-9 cells, but not to K562 cells. Topoisomerase II (Topo II) activity was decreased in K562/D1-9 cells. In contrast to other drugs, such as doxorubicin and vincristine, verapamil could not reverse drug resistance to VP-16 in the K562/D1-9 cell line, suggesting the importance of Topo II as the target of MDR. Protein kinase C (PKC) level was higher in K562/D1-9 than in K562. These findings suggested that the mechanism of MDR in this cell line might be multifactorial, including PGP, topo II and PKC. The K562/D1-9 cell line may be a good model for studying drug resistance in leukemia chemotherapy.
authors.affiliation: First Department of Internal Medicine, Fukui Medical School, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Urasaki
authors.forename: T
authors.initials: T
authors.lastname: Ueda
authors.forename: A
authors.initials: A
authors.lastname: Yoshida
authors.forename: T
authors.initials: T
authors.lastname: Fukushima
authors.forename: N
authors.initials: N
authors.lastname: Takeuchi
authors.forename: T
authors.initials: T
authors.lastname: Tsuruo
authors.forename: T
authors.initials: T
authors.lastname: Nakamura
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000378:metabolism*; D004250:DNA Topoisomerases, Type II / Q000378:metabolism; D003630:Daunorubicin / Q000378:metabolism*; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000201:enzymology / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology
chemical_list: D000903:Antibiotics, Antineoplastic; D011493:Protein Kinase C; D004250:DNA Topoisomerases, Type II; D003630:Daunorubicin