title: p56/p53lyn tyrosine kinase activation in mammalian cells treated with mitomycin C.
abstract: The present studies have examined the effects of mitomycin C (MMC), a genotoxic alkylating agent, on the activation of Src-like protein tyrosine kinases in HL-60 myeloid leukemia cells. The results demonstrate no detectable induction of p59fyn or pp60c-src activity. The response of HL-60 cells to MMC however was associated with rapid activation of p56/p53lyn. Similar findings were obtained with other alkylating agents such as nitrogen mustard and cis-platinum. Activation of p56/p53lyn was associated with increased autophosphorylation on tyrosine and sensitivity to the tyrosine kinase inhibitors herbimycin A and genistein. Studies with a glutathione S-transferase-Lyn fusion protein were performed to explore the potential significance of p56/p53lyn activation. Analysis of the adsorbates demonstrates interaction of Lyn with the cell cycle regulatory protein, p34cdc2. Coimmunoprecipitation studies further confirmed the association of p56/p53lyn and p34cdc2 in MMC-treated cells. We also demonstrate that p34cdc2 undergoes increased phosphorylation on tyrosine following MMC exposure and that p56/p53lyn phosphorylates the Tyr-15 site of p34cdc2 in vitro. These findings indicate that the cellular response to MMC includes activation of p56/p53lyn and that this event may contribute to signals transduced by the DNA damage-dependent mitotic checkpoint.
authors.affiliation: Division of Cancer Pharmacology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: S
authors.initials: S
authors.lastname: Kharbanda
authors.forename: Z M
authors.initials: ZM
authors.lastname: Yuan
authors.forename: N
authors.initials: N
authors.lastname: Taneja
authors.forename: R
authors.initials: R
authors.lastname: Weichselbaum
authors.forename: D
authors.initials: D
authors.lastname: Kufe
mesh_terms: D000477:Alkylating Agents / Q000494:pharmacology; D000595:Amino Acid Sequence; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D016685:Mitomycin / Q000494:pharmacology*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000378:metabolism; D019061:src-Family Kinases
chemical_list: D000477:Alkylating Agents; D014443:Tyrosine; D016685:Mitomycin; D011505:Protein-Tyrosine Kinases; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases