title: Depsipeptide (FK228) preferentially induces apoptosis in BCR/ABL-expressing cell lines and cells from patients with chronic myelogenous leukemia in blast crisis.
abstract: Resistance to imatinib can occur in patients with chronic myelogenous leukemia (CML). In this study, we report mechanisms of action of histone deacetylase (HDAC) inhibitor, depsipeptide (FK228) in BCR/ABL-expressing cell lines and its effectiveness in imatinib-resistant cells from patients with blast crisis of CML. FK228 potently induced apoptosis of TF-1 BCR/ABL, K562, and H7 BCR/ABL cells. We found that histone H4, BCR/ABL, heat shock protein 90 (HSP-90), p53, focal adhesion kinase (FAK), paxillin, and retinoblastoma protein (Rb) were acetylated in the treated cells. Cells were also blocked in G(2)/M phase of the cell cycle and activity of mitogen-activated protein kinase (MAPK) was blocked, but p38MAPK (p38) was activated. Inhibitor of apoptosis proteins (IAPs) were suppressed, and common results of apoptotic induction were observed, such as caspase-3, caspase-9, and poly(ADP-ribose) polymerase (PARP) activation. Although p38 was phosphorylated after FK228 treatment, histone H4 acetylation, caspase-3 activation, and apoptosis were not inhibited by treatment with the p38 inhibitor SB203580. We also found that human telomerase reverse transcriptase (hTERT) ShRNA-transfected cells demonstrated decreased FK228-induced apoptosis. Of clinical relevance, FK228-induced apoptosis of imatinib-resistant primary cells from patients with CML, who had progressed to blast crisis (BC) while receiving therapy with imatinib. In conclusion, FK228 potently induces apoptosis of CML cells by acetylation and degradation of BCR/ABL protein. Our study suggests how FK228 may mediate its effects on imatinib-resistant CML cells.
authors.affiliation: First Department of Internal Medicine, Tokyo Medical University, Tokyo, Japan. okabe@tokyo-med.ac.jp
authors.forename: Seiichi
authors.initials: S
authors.lastname: Okabe
authors.forename: Tetsuzo
authors.initials: T
authors.lastname: Tauchi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nakajima
authors.forename: Goro
authors.initials: G
authors.lastname: Sashida
authors.forename: Akihiko
authors.initials: A
authors.lastname: Gotoh
authors.forename: Hal E
authors.initials: HE
authors.lastname: Broxmeyer
authors.forename: Junko H
authors.initials: JH
authors.lastname: Ohyashiki
authors.forename: Kazuma
authors.initials: K
authors.lastname: Ohyashiki
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use; D017209:Apoptosis / Q000502:physiology*; D001549:Benzamides; D001752:Blast Crisis / Q000188:drug therapy*; D002453:Cell Cycle / Q000502:physiology; D002460:Cell Line; D049109:Cell Proliferation; D047630:Depsipeptides / Q000627:therapeutic use*; D019008:Drug Resistance, Neoplasm; D016044:Fusion Proteins, bcr-abl / Q000235:genetics / Q000378:metabolism*; D056572:Histone Deacetylase Inhibitors; D006801:Humans; D000068877:Imatinib Mesylate; D051034:Inhibitor of Apoptosis Proteins / Q000378:metabolism; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000188:drug therapy / Q000473:pathology; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D010879:Piperazines / Q000627:therapeutic use; D011743:Pyrimidines / Q000627:therapeutic use; D019098:Telomerase / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D000903:Antibiotics, Antineoplastic; D000970:Antineoplastic Agents; D001549:Benzamides; D047630:Depsipeptides; D056572:Histone Deacetylase Inhibitors; D051034:Inhibitor of Apoptosis Proteins; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; C087123:romidepsin; D016044:Fusion Proteins, bcr-abl; D020928:Mitogen-Activated Protein Kinases; D019098:Telomerase