title: Ponatinib may overcome resistance of FLT3-ITD harbouring additional point mutations, notably the previously refractory F691I mutation.
abstract: Fms-like tyrosine kinase (FLT3) mutations are the most frequent mutations in patients with acute myeloid leukaemia (AML) that confer a poor prognosis. Constitutively active FLT3-ITD (internal tandem duplications) mutations define a promising target for therapeutic approaches using small molecule inhibitors. However, several point mutations of the FLT3 tyrosine kinase domain (FLT3-TKD) have been identified to mediate resistance towards FLT3 tyrosine kinase inhibitors (FLT3-TKI), including secondary mutations of FLT3. We investigated the cellular effects of the recently characterised FLT3-TKI ponatinib (AP24534) on murine myeloid cells transfected with FLT3-ITD with or without additional point mutations of the FLT3-TKD including the (so far) multi-resistant F691I mutation. Ponatinib effectively induced apoptosis not only in the parental FLT3-ITD cell line but also in all stably transfected subclones harbouring additional FLT3-TKD point mutations (N676D, F691I or G697R). These observations correlated with a strong inhibition of FLT3-ITD and its downstream targets STAT5, AKT and ERK1/2 upon ponatinib incubation, as determined by Western blotting. We conclude that ponatinib represents a promising FLT3-TKI that should be further investigated in clinical trials. The targeted therapy of FLT3-ITD-positive AML with ponatinib might be associated with a lower frequency of secondary resistance caused by acquired FLT3-TKD mutations.
authors.affiliation: Department of Haematology/Oncology, Clinic for Internal Medicine II, Jena University Hospital, Jena.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Zirm
authors.forename: Bärbel
authors.initials: B
authors.lastname: Spies-Weisshart
authors.forename: Florian
authors.initials: F
authors.lastname: Heidel
authors.forename: Ulf
authors.initials: U
authors.lastname: Schnetzke
authors.forename: Frank-Dietmar
authors.initials: FD
authors.lastname: Böhmer
authors.forename: Andreas
authors.initials: A
authors.lastname: Hochhaus
authors.forename: Thomas
authors.initials: T
authors.lastname: Fischer
authors.forename: Sebastian
authors.initials: S
authors.lastname: Scholl
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology*; D015470:Leukemia, Myeloid, Acute / Q000235:genetics / Q000378:metabolism; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D010766:Phosphorylation / Q000187:drug effects; D017354:Point Mutation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D011724:Pyridazines / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D051941:fms-Like Tyrosine Kinase 3 / Q000037:antagonists & inhibitors / Q000235:genetics*
chemical_list: D000970:Antineoplastic Agents; D007093:Imidazoles; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D047428:Protein Kinase Inhibitors; D019253:Proto-Oncogene Proteins c-bcl-2; D011724:Pyridazines; C545373:ponatinib; D051941:fms-Like Tyrosine Kinase 3