title: Identification of Ponatinib as a potent inhibitor of growth, migration, and activation of neoplastic eosinophils carrying FIP1L1-PDGFRA.
abstract: In chronic eosinophilic leukemia, the transforming oncoprotein FIP1L1-PDGFRA is a major target of therapy. In most patients, the tyrosine kinase inhibitor (TKI) imatinib induces complete remission. For patients who are intolerant or resistant, novel TKIs have been proposed. We examined the in vitro effects of 14 kinase blockers on growth and function of EOL-1 cells, a FIP1L1-PDGFRA(+) eosinophil cell line. Major growth-inhibitory effects were seen with all PDGFR-blocking agents, with IC50 values in the low nanomolar range: ponatinib, 0.1-0.2 nmol/L; sorafenib, 0.1-0.2 nmol/L; masitinib, 0.2-0.5 nmol/L; nilotinib, 0.2-1.0 nmol/L; dasatinib, 0.5-2.0 nmol/L; sunitinib, 1-2 nmol/L; midostaurin, 5-10 nmol/L. These drugs were also found to block activation of PDGFR-downstream signaling molecules, including Akt, S6, and STAT5 in EOL-1 cells. All effective TKIs produced apoptosis in EOL-1 cells as determined by microscopy, Annexin-V/PI, and caspase-3 staining. In addition, PDGFR-targeting TKIs were found to inhibit cytokine-induced migration of EOL-1 cells. In all bioassays used, ponatinib was found to be the most potent compound in EOL-1 cells. In addition, ponatinib was found to downregulate expression of the activation-linked surface antigen CD63 on EOL-1 cells and to suppress the growth of primary neoplastic eosinophils. We also examined drug effects on Ba/F3 cells expressing two clinically relevant, imatinib-resistant, mutant forms of FIP1L1-PDGFRA, namely T674I and D842V. Strong inhibitory effects on both mutants were seen only with ponatinib. In summary, novel PDGFR-targeting TKIs may be alternative agents for the treatment of patients with imatinib-resistant chronic eosinophilic leukemia. Although several different PDGFR-targeting agents are effective, the most potent drug appears to be ponatinib.
authors.affiliation: Division of Hematology and Hemostaseology, Department of Internal Medicine I, Medical University of Vienna, Austria.
authors.forename: Irina
authors.initials: I
authors.lastname: Sadovnik
authors.affiliation: Center for Human Genetics, KU Leuven, Leuven, Belgium; Center for Human Genetics, University Hospital Leuven, Leuven, Belgium.
authors.forename: Els
authors.initials: E
authors.lastname: Lierman
authors.affiliation: Division of Hematology and Hemostaseology, Department of Internal Medicine I, Medical University of Vienna, Austria; Ludwig Boltzmann Cluster Oncology, Vienna, Austria.
authors.forename: Barbara
authors.initials: B
authors.lastname: Peter
authors.affiliation: Division of Hematology and Hemostaseology, Department of Internal Medicine I, Medical University of Vienna, Austria; Ludwig Boltzmann Cluster Oncology, Vienna, Austria.
authors.forename: Harald
authors.initials: H
authors.lastname: Herrmann
authors.affiliation: Division of Hematology and Hemostaseology, Department of Internal Medicine I, Medical University of Vienna, Austria.
authors.forename: Verena
authors.initials: V
authors.lastname: Suppan
authors.affiliation: Division of Hematology and Hemostaseology, Department of Internal Medicine I, Medical University of Vienna, Austria.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Stefanzl
authors.affiliation: Childrens Cancer Research Institute, Vienna, Austria.
authors.forename: Oskar
authors.initials: O
authors.lastname: Haas
authors.affiliation: Childrens Cancer Research Institute, Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Lion
authors.affiliation: Institute of Immunology, Medical University of Vienna, Austria.
authors.forename: Winfried
authors.initials: W
authors.lastname: Pickl
authors.affiliation: Center for Human Genetics, KU Leuven, Leuven, Belgium; Center for Human Genetics, University Hospital Leuven, Leuven, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: Cools
authors.affiliation: Center for Human Genetics, KU Leuven, Leuven, Belgium; Center for Human Genetics, University Hospital Leuven, Leuven, Belgium.
authors.forename: Peter
authors.initials: P
authors.lastname: Vandenberghe
authors.affiliation: Division of Hematology and Hemostaseology, Department of Internal Medicine I, Medical University of Vienna, Austria; Ludwig Boltzmann Cluster Oncology, Vienna, Austria. Electronic address: peter.valent@meduniwien.ac.at.
authors.forename: Peter
authors.initials: P
authors.lastname: Valent
mesh_terms: D019943:Amino Acid Substitution; D017304:Annexin A5 / Q000096:biosynthesis / Q000235:genetics; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects* / Q000235:genetics; D049109:Cell Proliferation / Q000187:drug effects*; D004354:Drug Screening Assays, Antitumor; D004804:Eosinophils / Q000378:metabolism* / Q000473:pathology; D005260:Female; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects / Q000235:genetics; D006801:Humans; D017681:Hypereosinophilic Syndrome / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D007093:Imidazoles / Q000494:pharmacology*; D008297:Male; D020125:Mutation, Missense; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D011724:Pyridazines / Q000494:pharmacology*; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics / Q000378:metabolism*; D019893:Ribosomal Protein S6 Kinases / Q000235:genetics / Q000378:metabolism; D050799:STAT5 Transcription Factor / Q000235:genetics / Q000378:metabolism; D060149:Tetraspanin 30 / Q000096:biosynthesis / Q000235:genetics; D039221:mRNA Cleavage and Polyadenylation Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D017304:Annexin A5; C554586:CD63 protein, human; D007093:Imidazoles; D015514:Oncogene Proteins, Fusion; D011724:Pyridazines; D050799:STAT5 Transcription Factor; D060149:Tetraspanin 30; D039221:mRNA Cleavage and Polyadenylation Factors; C545373:ponatinib; C479819:FIP1L1-PDGFRA fusion protein, human; D020796:Receptor, Platelet-Derived Growth Factor alpha; D051057:Proto-Oncogene Proteins c-akt; D019893:Ribosomal Protein S6 Kinases