A FLT3-targeted tyrosine kinase inhibitor is cytotoxic to leukemia cells in vitro and in vivo.
Constitutively activating internal tandem duplication (ITD) and point mutations of the receptor tyrosine kinase FLT3 are present in up to 41% of patients with acute myeloid leukemia (AML). These FLT3/ITD mutations are likely to be important because their presence is associated with a poor prognosis. Both types of mutations appear to activate the tyrosine kinase activity of FLT3. We describe here the identification and characterization of the indolocarbazole derivative CEP-701 as a FLT3 inhibitor. This drug potently and selectively inhibits autophosphorylation of wild-type and constitutively activated mutant FLT3 in vitro in FLT3/ITD-transfected cells and in human FLT3-expressing myeloid leukemia-derived cell lines. We demonstrate that CEP-701 induces a cytotoxic effect on cells in a dose-responsive fashion that parallels the inhibition of FLT3. STAT5 and ERK1/2, downstream targets of FLT3 in the signaling pathway, are inhibited in response to FLT3 inhibition. In primary leukemia blasts from AML patients harboring FLT3/ITD mutations, FLT3 is also inhibited, with an associated cytotoxic response. Finally, using a mouse model of FLT3/ITD leukemia, we demonstrate that the drug inhibits FLT3 phosphorylation in vivo and prolongs survival. These findings form the basis for a planned clinical trial of CEP-701 in patients with AML harboring FLT3- activating mutations.
Levis
Mark
M
Johns Hopkins University School of Medicine, Department of Oncology, Baltimore, MD 21231-1000, USA.
Allebach
Jeffrey
J
Tse
Kam-Fai
KF
Zheng
Rui
R
Baldwin
Brenda R
BR
Smith
B Douglas
BD
Jones-Bolin
Susan
S
Ruggeri
Bruce
B
Dionne
Craig
C
Small
Donald
D
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D001854:Bone Marrow Cells / Q000201:enzymology / Q000473:pathology; D002227:Carbazoles / Q000633:toxicity*; D002470:Cell Survival / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005663:Furans; D006801:Humans; D007211:Indoles; D007700:Kinetics; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy / Q000201:enzymology / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D017354:Point Mutation; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics*; D020794:Receptor Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured; D051941:fms-Like Tyrosine Kinase 3
D000970:Antineoplastic Agents; D002227:Carbazoles; D004791:Enzyme Inhibitors; D005663:Furans; D007211:Indoles; D011518:Proto-Oncogene Proteins; C119379:lestaurtinib; C497970:FLT3 protein, human; C497971:Flt3 protein, mouse; D020794:Receptor Protein-Tyrosine Kinases; D051941:fms-Like Tyrosine Kinase 3; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases