title: Effects of recombinant human interferon-alpha, beta and gamma on the antiproliferative activity of cytarabine in K562 human myeloid leukemia clonogenic cells.
abstract: The effects of recombinant human interferon-alpha, beta and gamma (IFN) on the antiproliferative activity of cytarabine (ara-C) in K562 human myeloid leukemia clonogenic cells were studied in an agar capillary microassay. The addition of IFN-alpha did not affect the antiproliferative activity of ara-C in K562 cultures treated with low concentrations of ara-C: 10-50 nM, whereas in those treated with high concentrations of ara-C: 100-500 nM, IFN-alpha significantly reduced the antiproliferative activity of ara-C. The addition of 3 x 10(4) U/ml IFN-alpha to ara-C-treated K562 cultures increased the IC50 of ara-C on day 5 from 102 to 214 nM, i.e. ara-C+IFN-alpha was about twofold less potent than ara-C alone. Low concentrations of IFN-beta and IFN-gamma did not affect the antiproliferative activity of ara-C on K562 colonies, but high concentrations of these two interferons reduced the antiproliferative activity of ara-C. The addition of 4 x 10(3) U/ml IFN-beta or 10(4) U/ml IFN-gamma increased the IC50 of ara-C on day 5 to 304 nM or to 316 nM, respectively, i.e. ara-C+IFN-beta or IFN-gamma was about threefold less potent than ara-C alone. The significant reduction of the desired antiproliferative activity of ara-C by the three interferons was reproduced in liquid suspension cultures of K562 cells on day 4 in the following order: IFN-gamma greater than IFN-beta greater than IFN-alpha. The present negative interactions of the three interferons with ara-C particularly at high concentrations, may caution against the clinical use of the combination of ara-C and interferon in the treatment of myeloid leukemia patients.
authors.affiliation: Leukaemia Research, Freie Universität Berlin, Germany.
authors.forename: H T
authors.initials: HT
authors.lastname: Hassan
authors.forename: C
authors.initials: C
authors.lastname: Tsiriyotis
authors.forename: H R
authors.initials: HR
authors.lastname: Maurer
mesh_terms: D002455:Cell Division / Q000187:drug effects; D003561:Cytarabine / Q000494:pharmacology*; D004347:Drug Interactions; D006801:Humans; D007370:Interferon Type I / Q000494:pharmacology*; D016899:Interferon-beta / Q000494:pharmacology*; D007371:Interferon-gamma / Q000494:pharmacology*; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000188:drug therapy*; D011994:Recombinant Proteins / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014410:Tumor Stem Cell Assay
chemical_list: D007370:Interferon Type I; D011994:Recombinant Proteins; D003561:Cytarabine; D016899:Interferon-beta; D007371:Interferon-gamma