title: 1-beta-D-arabinofuranosylcytosine activates tyrosine phosphorylation of p34cdc2 and its association with the Src-like p56/p53lyn kinase in human myeloid leukemia cells.
abstract: Recent studies have demonstrated that treatment of human myeloid leukemia cells with 1-beta-D-arabinofuranosylcytosine (ara-C) is associated with activation of serine/threonine protein kinases and early response gene expression. The present work has examined the involvement of protein tyrosine phosphorylation in ara-C-induced responses of HL-60 myeloid leukemia cells. The results of immunoprecipitation studies demonstrate that HL-60 cells respond to ara-C with tyrosine phosphorylation of the cell cycle regulatory protein p34cdc2 and a decrease in the activity of this kinase. This effect was detectable at 15 min of ara-C exposure. Coimmunoprecipitations with anti-p34cdc2 support binding of this protein to the Src-like p56/p53lyn tyrosine kinase in ara-C-treated, but not untreated, cells. The results further demonstrate that ara-C treatment is associated with a dose-dependent activation of p56/p53lyn and that ara-C-induced p56/p53lyn activity is blocked by the protein tyrosine inhibitors herbimycin A and genistein. Studies with a glutathione S-transferase-Lyn fusion protein confirm interaction of p34cdc2 and p56/p53lyn in lysates of ara-C-treated cells. Moreover, we demonstrate that (1) p56/p53lyn phosphorylates Tyr-15 of p34cdc2 in vitro and (2) phosphorylation of p34cdc2 by p56/p53lyn inhibits p34cdc2 activity. These findings indicate that the cellular response to ara-C includes activation of p56/p53lyn and that association of p56/p53lyn with p34cdc2 may contribute to regulation of the cell cycle progression in ara-C-treated cells.
authors.affiliation: Division of Cancer Pharmacology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: Z M
authors.initials: ZM
authors.lastname: Yuan
authors.forename: S
authors.initials: S
authors.lastname: Kharbanda
authors.forename: D
authors.initials: D
authors.lastname: Kufe
mesh_terms: D000595:Amino Acid Sequence; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D003561:Cytarabine / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D007951:Leukemia, Myeloid / Q000201:enzymology*; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D019000:Phosphotyrosine; D011233:Precipitin Tests; D011485:Protein Binding; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism; D019061:src-Family Kinases
chemical_list: D046911:Macromolecular Substances; D003561:Cytarabine; D019000:Phosphotyrosine; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases; D016203:CDC2 Protein Kinase