Inhibition of Bcl-2 Synergistically Enhances the Antileukemic Activity of Midostaurin and Gilteritinib in Preclinical Models of FLT3-Mutated Acute Myeloid Leukemia

Clin Cancer Res. 2019 Nov 15;25(22):6815-6826. doi: 10.1158/1078-0432.CCR-19-0832. Epub 2019 Jul 18.


Purpose: To investigate the efficacy of the combination of the FLT3 inhibitors midostaurin or gilteritinib with the Bcl-2 inhibitor venetoclax in FLT3-internal tandem duplication (ITD) acute myeloid leukemia (AML) and the underlying molecular mechanism.

Experimental design: Using both FLT3-ITD cell lines and primary patient samples, Annexin V-FITC/propidium iodide staining and flow cytometry analysis were used to quantify cell death induced by midostaurin or gilteritinib, alone or in combination with venetoclax. Western blot analysis was performed to assess changes in protein expression levels of members of the JAK/STAT, MAPK/ERK, and PI3K/AKT pathways, and members of the Bcl-2 family of proteins. The MV4-11-derived xenograft mouse model was used to assess in vivo efficacy of the combination of gilteritinib and venetoclax. Lentiviral overexpression of Mcl-1 was used to confirm its role in cell death induced by midostaurin or gilteritinib with venetoclax. Changes of Mcl-1 transcript levels were assessed by RT-PCR.

Results: The combination of midostaurin or gilteritinib with venetoclax potently and synergistically induces apoptosis in FLT3-ITD AML cell lines and primary patient samples. The FLT3 inhibitors induced downregulation of Mcl-1, enhancing venetoclax activity. Phosphorylated-ERK expression is induced by venetoclax but abolished by the combination of venetoclax with midostaurin or gilteritinib. Simultaneous downregulation of Mcl-1 by midostaurin or gilteritinib and inhibition of Bcl-2 by venetoclax results in "free" Bim, leading to synergistic induction of apoptosis. In vivo results show that gilteritinib in combination with venetoclax has therapeutic potential.

Conclusions: Inhibition of Bcl-2 via venetoclax synergistically enhances the efficacy of midostaurin and gilteritinib in FLT3-mutated AML.See related commentary by Perl, p. 6567.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aniline Compounds / pharmacology*
  • Animals
  • Apoptosis / drug effects
  • Biomarkers, Tumor
  • Bridged Bicyclo Compounds, Heterocyclic / pharmacology
  • Cell Line, Tumor
  • Disease Models, Animal
  • Drug Synergism
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Gene Duplication
  • Gene Expression Regulation, Leukemic / drug effects
  • Humans
  • Leukemia, Myeloid, Acute / drug therapy
  • Leukemia, Myeloid, Acute / genetics*
  • Leukemia, Myeloid, Acute / metabolism*
  • Leukemia, Myeloid, Acute / pathology
  • Mice
  • Mutation*
  • Myeloid Cell Leukemia Sequence 1 Protein / genetics
  • Myeloid Cell Leukemia Sequence 1 Protein / metabolism
  • Protein Kinase Inhibitors / pharmacology*
  • Proto-Oncogene Proteins c-bcl-2 / antagonists & inhibitors*
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Pyrazines / pharmacology*
  • Staurosporine / analogs & derivatives*
  • Staurosporine / pharmacology
  • Sulfonamides / pharmacology
  • Xenograft Model Antitumor Assays
  • fms-Like Tyrosine Kinase 3 / genetics*


  • Aniline Compounds
  • BCL2 protein, human
  • Biomarkers, Tumor
  • Bridged Bicyclo Compounds, Heterocyclic
  • MCL1 protein, human
  • Myeloid Cell Leukemia Sequence 1 Protein
  • Protein Kinase Inhibitors
  • Proto-Oncogene Proteins c-bcl-2
  • Pyrazines
  • Sulfonamides
  • gilteritinib
  • FLT3 protein, human
  • fms-Like Tyrosine Kinase 3
  • Extracellular Signal-Regulated MAP Kinases
  • Staurosporine
  • midostaurin
  • venetoclax