Identification of AKN-032, a novel 2-aminopyrazine tyrosine kinase inhibitor, with significant preclinical activity in acute myeloid leukemia.
Aberrant signal transduction by mutant or overexpressed protein kinases has emerged as a promising target for treatment of acute myeloid leukemia (AML). We here present a novel low molecular weight kinase inhibitor, AKN-032, targeting the FMS-like tyrosine kinase 3 (FLT3) and discovered in a new type of screening funnel combining the target therapy approach with sequential cellular screens. AKN-032 was identified among 150 selected hits from three different high throughput kinase screens. Further characterization showed inhibitory activity on FLT3 enzyme with an IC(50) of 70 nM. Western blot analysis revealed reduced autophosphorylation of the FLT3-receptor in AML cell line MV4-11 cells after exposure to AKN-032. Flow cytometry disclosed cytotoxic activity against MV4-11, but not against non-malignant 3T3-L1 fibroblast cells. Using a fluorometric microculture cytotoxicity assay, AKN-032 was tested against 15 cell lines and displayed a potent cytotoxic activity in AML cell lines MV4-11 (IC(50)=0.4 μM) and Kasumi-1 (IC(50)=2.3 μM). AKN-032 was also highly cytotoxic in tumor cells from AML patients in vitro. Furthermore, AKN-032 demonstrated significant antileukemic effect in a relatively resistant in vivo hollow fiber mouse model. No major toxicity was observed in the animals. In conclusion, AKN-032 is a promising new kinase inhibitor with significant in vivo and in vitro activity in AML. Results from the hollow fiber mouse assay suggest a favorable toxicity profile. Future studies will focus on pharmacokinetic properties, toxicity as well as further clarifying the mechanisms of action of AKN-032 in AML.
Eriksson
Anna
A
Department of Medical Sciences, Uppsala University, Sweden. anna.eriksson@medsci.uu.se
Höglund
Martin
M
Lindhagen
Elin
E
Aleskog
Anna
A
Hassan
Sadia Bashir
SB
Ekholm
Carina
C
Fhölenhag
Karin
K
Jensen
Annika Jenmalm
AJ
Löthgren
Agneta
A
Scobie
Martin
M
Larsson
Rolf
R
Parrow
Vendela
V
D000328:Adult; D000368:Aged; D000818:Animals; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000187:drug effects / Q000201:enzymology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D015479:Leukemia, Myelomonocytic, Acute / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D008297:Male; D051379:Mice; D008875:Middle Aged; D015394:Molecular Structure; D011719:Pyrazines / Q000009:adverse effects / Q000737:chemistry* / Q000494:pharmacology / Q000627:therapeutic use*; D023041:Xenograft Model Antitumor Assays; D055815:Young Adult; D051941:fms-Like Tyrosine Kinase 3 / Q000037:antagonists & inhibitors*
C553106:AKN 032; D000970:Antineoplastic Agents; D011719:Pyrazines; C079424:2-aminopyrazine; D051941:fms-Like Tyrosine Kinase 3