title: Involvement of Akt kinase in the action of STI571 on chronic myelogenous leukemia cells.
abstract: To elucidate the role of mitogen-activated protein kinases (MAPKs) and Akt kinase in leukemogenesis caused by the breakpoint cluster region (BCR)-Abelson (ABL) tyrosine kinase oncoprotein, we examined the activities of MAPKs and Akt kinase and their roles in the action of STI571, a specific inhibitor of BCR-ABL tyrosine kinase, in chronic myelogenous leukemia (CML) cells. We found that extracellular signal-regulated kinase (ERK) 1/2 and Akt kinase are constitutively active in the chronic phase of CML, blast crisis of CML, and the CML-derived K562 cell line. Both interferon-alpha and STI571 suppressed ERK1/2 activity in K562 cells. In contrast, Akt kinase activity was inhibited only by STI571. K562 cell proliferation was markedly suppressed by LY294002, a specific inhibitor of PI3K/Akt kinase, and STI571 but not by PD98059, a specific inhibitor of MEK1/2. In addition, caspase-3 was activated by treatment of cells with STI571 and LY294002 but not with PD98059. These data indicate that Akt kinase may play a role in the proliferation of CML leukemia cells and the action of STI571. Primary leukemia cells from patients with CML blast crisis did not show inhibition of ERK1/2 or Akt kinase activity and were resistant to caspase-3-associated apoptosis after treatment with STI571. These findings suggest that STI571 does not effectively block signaling molecules downstream of the BCR-ABL tyrosine kinase in some cases of CML blast crisis.
authors.affiliation: Department of Medicine, Tokyo Women's Medical University Daini Hospital, 2-1-10 Nishiogu, Arakawa-ku, 116-8567, Tokyo, Japan.
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Kawauchi
authors.forename: Toshie
authors.initials: T
authors.lastname: Ogasawara
authors.forename: Masako
authors.initials: M
authors.lastname: Yasuyama
authors.forename: Shin ichiro
authors.initials: Si
authors.lastname: Ohkawa
mesh_terms: D000328:Adult; D000368:Aged; D017209:Apoptosis / Q000187:drug effects; D001549:Benzamides; D001752:Blast Crisis / Q000473:pathology; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D000068877:Imatinib Mesylate; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000201:enzymology / Q000209:etiology* / Q000473:pathology; D015466:Leukemia, Myeloid, Chronic-Phase / Q000473:pathology; D008297:Male; D008875:Middle Aged; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology; D010879:Piperazines / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D051057:Proto-Oncogene Proteins c-akt; D011743:Pyrimidines / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D001549:Benzamides; D010879:Piperazines; D011518:Proto-Oncogene Proteins; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D011505:Protein-Tyrosine Kinases; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases