The protein tyrosine kinase inhibitor SU5614 inhibits FLT3 and induces growth arrest and apoptosis in AML-derived cell lines expressing a constitutively activated FLT3.
Activating mutations of the protein tyrosine kinase (PTK) FLT3 can be found in approximately 30% of patients with acute myeloid leukemia (AML), thereby representing the most frequent single genetic alteration in AML. These mutations occur in the juxtamembrane (FLT3 length mutations; FLT3-LMs) and the second tyrosine kinase domain of FLT3-TKD and confer interleukin 3 (IL-3)-independent growth to Ba/F3 cells. In the mouse bone marrow transplantation model, FLT3-LMs induce a myeloproliferative syndrome stressing their transforming activity in vivo. In this study, we analyzed the pro-proliferative and antiapoptotic potential of FLT3 in FLT3-LM/TKD-mutation-transformed Ba/F3 cells and AML-derived cell lines. The PTK inhibitor SU5614 has inhibitory activity for FLT3 and selectively induces growth arrest, apoptosis, and cell cycle arrest in Ba/F3 and AML cell lines expressing a constitutively activated FLT3. In addition, the compound reverts the antiapoptotic and pro-proliferative activity of FLT3 ligand (FL) in FL-dependent cells. No cytotoxic activity of SU5614 was found in leukemic cell lines that express a nonactivated FLT3 or no FLT3 protein. At the biochemical level, SU5614 down-regulated the activity of the hyperphosphorylated FLT3 receptor and its downstream targets, signal transducer and activator of (STAT) 3, STAT5, and mitogen-activated protein kinase (MAPK), and the STAT5 target genes BCL-X(L) and p21. Our results show that SU5614 is a PTK inhibitor of FLT3 and has antiproliferative and proapoptotic activity in AML-derived cell lines that endogenously express an activated FLT3 receptor. The selective and potent cytotoxicity of FLT3 PTK inhibitors support a clinical strategy of targeting FLT3 as a new molecular treatment option for patients with FLT3-LM/TKD-mutation(+) AML.
Spiekermann
Karsten
K
Department of Medicine III, University Hospital Grosshadern, Clinical Cooperative Group Leukemia, GSF National Research Center for Environment and Health, Munich, Germany. spiekermann@gsf.de
Dirschinger
Ralf J
RJ
Schwab
Ruth
R
Bagrintseva
Ksenia
K
Faber
Florian
F
Buske
Christian
C
Schnittger
Susanne
S
Kelly
Louise M
LM
Gilliland
D Gary
DG
Hiddemann
Wolfgang
W
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D016026:Bone Marrow Transplantation; D002455:Cell Division / Q000187:drug effects*; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005434:Flow Cytometry; D015870:Gene Expression; D049452:Green Fluorescent Proteins; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D015470:Leukemia, Myeloid, Acute / Q000235:genetics / Q000473:pathology*; D008164:Luminescent Proteins / Q000235:genetics; D051379:Mice; D008894:Milk Proteins; D020928:Mitogen-Activated Protein Kinases; D016296:Mutagenesis; D009154:Mutation; D009196:Myeloproliferative Disorders / Q000235:genetics; D016133:Polymerase Chain Reaction; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D020794:Receptor Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics; D050799:STAT5 Transcription Factor; D015534:Trans-Activators / Q000037:antagonists & inhibitors; D014162:Transfection; D014407:Tumor Cells, Cultured; D051941:fms-Like Tyrosine Kinase 3
D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D007211:Indoles; D008164:Luminescent Proteins; D008894:Milk Proteins; D011518:Proto-Oncogene Proteins; D050799:STAT5 Transcription Factor; C416849:SU 5614; D015534:Trans-Activators; D049452:Green Fluorescent Proteins; C497970:FLT3 protein, human; C497971:Flt3 protein, mouse; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases; D051941:fms-Like Tyrosine Kinase 3; D020928:Mitogen-Activated Protein Kinases