title: PKC412 inhibits in vitro growth of neoplastic human mast cells expressing the D816V-mutated variant of KIT: comparison with AMN107, imatinib, and cladribine (2CdA) and evaluation of cooperative drug effects.
abstract: In most patients with systemic mastocytosis (SM), including aggressive SM and mast cell leukemia (MCL), neoplastic cells express the oncogenic KIT mutation D816V. KIT D816V is associated with constitutive tyrosine kinase (TK) activity and thus represents an attractive drug target. However, imatinib and most other TK inhibitors fail to block the TK activity of KIT D816V. We show that the novel TK-targeting drugs PKC412 and AMN107 counteract TK activity of D816V KIT and inhibit the growth of Ba/F3 cells with doxycycline-inducible expression of KIT D816V as well as the growth of primary neoplastic mast cells and HMC-1 cells harboring this KIT mutation. PKC412 was a superior agent with median inhibitory concentration (IC(50)) values of 50 to 250 nM without differences seen between HMC-1 cells exhibiting or lacking KIT D816V. By contrast, AMN107 exhibited more potent effects in KIT D816V(-) HMC-1 cells. Corresponding results were obtained with Ba/F3 cells exhibiting wild-type or D816V-mutated KIT. The growth-inhibitory effects of PKC412 and AMN107 on HMC-1 cells were associated with induction of apoptosis and down-regulation of CD2 and CD63. PKC412 was found to cooperate with AMN107, imatinib, and cladribine (2CdA) in producing growth inhibition in HMC-1, but synergistic drug interactions were observed only in cells lacking KIT D816V. Together, PKC412 and AMN107 represent promising novel agents for targeted therapy of SM.
authors.affiliation: Department of Internal Medicine I, Division of Hematology and Hemostaseology, Center of Excellence in Clinical and Experimental Oncology, Institute of Immunology, Medical University of Vienna, Austria.
authors.forename: Karoline V
authors.initials: KV
authors.lastname: Gleixner
authors.forename: Matthias
authors.initials: M
authors.lastname: Mayerhofer
authors.forename: Karl J
authors.initials: KJ
authors.lastname: Aichberger
authors.forename: Sophia
authors.initials: S
authors.lastname: Derdak
authors.forename: Karoline
authors.initials: K
authors.lastname: Sonneck
authors.forename: Alexandra
authors.initials: A
authors.lastname: Böhm
authors.forename: Alexander
authors.initials: A
authors.lastname: Gruze
authors.forename: Puchit
authors.initials: P
authors.lastname: Samorapoompichit
authors.forename: Paul W
authors.initials: PW
authors.lastname: Manley
authors.forename: Doriano
authors.initials: D
authors.lastname: Fabbro
authors.forename: Winfried F
authors.initials: WF
authors.lastname: Pickl
authors.forename: Christian
authors.initials: C
authors.lastname: Sillaber
authors.forename: Peter
authors.initials: P
authors.lastname: Valent
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015703:Antigens, CD / Q000378:metabolism; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001549:Benzamides; D018801:CD2 Antigens / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D017338:Cladribine / Q000008:administration & dosage; D015536:Down-Regulation; D004318:Doxycycline / Q000494:pharmacology; D004353:Drug Evaluation, Preclinical; D004347:Drug Interactions; D004357:Drug Synergism; D005260:Female; D006801:Humans; D000068877:Imatinib Mesylate; D016130:Immunophenotyping; D066298:In Vitro Techniques; D007946:Leukemia, Mast-Cell / Q000188:drug therapy* / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D010766:Phosphorylation / Q000187:drug effects; D010879:Piperazines / Q000008:administration & dosage; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics*; D011743:Pyrimidines / Q000008:administration & dosage; D019311:Staurosporine / Q000031:analogs & derivatives* / Q000494:pharmacology; D060149:Tetraspanin 30
chemical_list: D000900:Anti-Bacterial Agents; D015703:Antigens, CD; D001549:Benzamides; D018801:CD2 Antigens; C554586:CD63 protein, human; D010879:Piperazines; D010980:Platelet Membrane Glycoproteins; D011743:Pyrimidines; D060149:Tetraspanin 30; D017338:Cladribine; D000068877:Imatinib Mesylate; D019009:Proto-Oncogene Proteins c-kit; D011493:Protein Kinase C; C498826:nilotinib; D019311:Staurosporine; C059539:midostaurin; D004318:Doxycycline