title: Gö6976, a FLT3 kinase inhibitor, exerts potent cytotoxic activity against acute leukemia via inhibition of survivin and MCL-1.
abstract: Mutations of the FMS-like tyrosine kinase 3 (FLT3) have been reported in about a third of patients with acute myeloid leukemia (AML). The presence of FLT3 mutations confers a poor prognosis. Thus, pharmacological inhibitors of FLT3 are of therapeutic interest for AML. Gö6976 is an indolocarbazole with a similar structural backbone to staurosporine. In the present study, we demonstrated that Gö6976 displays a potent inhibitory activity against recombinant FLT3 using an in vitro kinase assay, with an IC50 value of 0.7nM. Gö6976 markedly inhibited the proliferation of human leukemia cells having FLT3-ITD such as MV4-11 and MOLM13. We also observed that Gö6976 showed minimal toxicity for human normal CD34(+) cells. Gö6976 suppressed the phosphorylation of FLT3 and downstream signaling molecules such as STAT3/5, Erk1/2, and Akt in MV4-11 and MOLM13 cells. Interestingly, induction of apoptosis by Gö6976 was associated with rapid and pronounced down-regulation of the anti-apoptotic protein survivin and MCL-1. Suppression of survivin protein expression by Gö6976 was due to the inhibition of transcription via the suppression of STAT3/5. On the other hand, Gö6976 induced proteasome-mediated degradation of MCL-1. Previously described FLT3 inhibitors such as PKC412 are bound by the human plasma protein, α1-acid glycoprotein, resulting in diminished inhibitory activity against FLT3. In contrast, we found that Gö6976 potently inhibited phosphorylation of FLT3 and exerted cytotoxicity in the presence of human serum. In conclusion, Gö6976 is a potent FLT3 inhibitor that displays a significant antiproliferative activity against leukemia cells with FLT3-ITD through the profound down-regulation of survivin and MCL-1.
authors.affiliation: Department of Hematology and Oncology, Faculty of Medicine, University of Fukui, Shimoaizuki 23-3, Mastuoka, Eiheiji-Chou, Fukui 910-1193, Japan; Translational Research Center, University of Fukui, Japan. Electronic address: ayoshi@u-fukui.ac.jp.
authors.forename: Akira
authors.initials: A
authors.lastname: Yoshida
authors.affiliation: Department of Hematology and Oncology, Faculty of Medicine, University of Fukui, Shimoaizuki 23-3, Mastuoka, Eiheiji-Chou, Fukui 910-1193, Japan.
authors.forename: Miyuki
authors.initials: M
authors.lastname: Ookura
authors.affiliation: Department of Hematology and Oncology, Faculty of Medicine, University of Fukui, Shimoaizuki 23-3, Mastuoka, Eiheiji-Chou, Fukui 910-1193, Japan.
authors.forename: Kouichi
authors.initials: K
authors.lastname: Zokumasu
authors.affiliation: Department of Hematology and Oncology, Faculty of Medicine, University of Fukui, Shimoaizuki 23-3, Mastuoka, Eiheiji-Chou, Fukui 910-1193, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Ueda
mesh_terms: D000208:Acute Disease; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D002227:Carbazoles / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D018922:HL-60 Cells; D006801:Humans; D015151:Immunoblotting; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics / Q000378:metabolism*; D007938:Leukemia / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D064549:Myeloid Cell Leukemia Sequence 1 Protein / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050796:STAT3 Transcription Factor / Q000378:metabolism; D050799:STAT5 Transcription Factor / Q000378:metabolism; D000077022:Survivin; D020298:U937 Cells; D051941:fms-Like Tyrosine Kinase 3 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
chemical_list: C107489:BIRC5 protein, human; D002227:Carbazoles; D004791:Enzyme Inhibitors; D051034:Inhibitor of Apoptosis Proteins; C579095:MCL1 protein, human; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D050796:STAT3 Transcription Factor; D050799:STAT5 Transcription Factor; D000077022:Survivin; C081021:Go 6976; D051941:fms-Like Tyrosine Kinase 3; D048049:Extracellular Signal-Regulated MAP Kinases; D046988:Proteasome Endopeptidase Complex
keywords: Apoptosis; FLT3 inhibitor; Gö6976; MCL-1; STAT3; Survivin