STI 571 inhibits the kinase activity of wild type and juxtamembrane C-kit mutants but not the exon 17 D816V mutation associated with mastocytosis

Michael Heinrich, Cecily L. Wait

    Research output: Contribution to journalArticle

    19 Citations (Scopus)

    Abstract

    STI 571 (formerly known as CGP 57148B), a 2-phenylaminopyrimidine derivative, is a known inhibitor of the the c-abl, bcr-abl, and platelet-derived growth factor receptor tyrosine kinases. This compound is currently being evaluated in clinical trials for the treatment of CML. We sought to extend the activity profile of STI 571 by testing its ability to inhibit the tyrosine kinase activity of mutant c-kit molecules associated with mastocytosis. We treated a human myeloid leukemia cell line (MO7e) that expresses wild-type c-kit protein with increasing doses of STI 571 prior to stimulation by Steel factor (SLF), the ligand for c-kit. SLF-induced c-kit autophosphorylation was effectively inhibited by STI 571 at concentrations of 0.1-10 u.M. The IC50 for inhibition of proliferation was 0.1-0.2 u.M. Additionally, we found that STI 571 blocked the anti-apoptotic activity of SLF. In contrast, the compound had no effect on cellular proliferation in response to GM-CSF. We also tested the activity of the compound using a human mast cell leukemia cell line (V560G HMC-1) that has an activating mutation of the juxtamembrane domain of c-kit (V560G). In V560G HMC-1 cells, STI 571 inhibited c-kit autophosphorylation, MAP kinase activation and Akt activation without altering total protein levels of c-kit, MAP kinase or Akt. The IC!0 for these effects was 0.01-0.1 U.M. The compound potently induced apoptosis (96.5% apoptosis at l U.M STI 571 vs. 8.5% in control cells). These results suggest that malignant mast cells are likely to be dependent upon the kinase activity of mutant c-kit molecules for proliferation and survival. However, most cases of human mastocytosis are associated with the activating mutations of the TK2 domain (D816V) rather than the juxtamembrane domain. In contrast to the results with wild type or V560G c-kit isoforms, STI 571 was unable to inhibit the kinase activity of the D816V mutant ckit (ICSO>5 U.M). Based on these studies, STI 571 would be predicted to be ineffective in the treatment of most patients with mastocytosis.

    Original languageEnglish (US)
    JournalBlood
    Volume96
    Issue number11 PART II
    StatePublished - 2000

    Fingerprint

    Mastocytosis
    Exons
    Phosphotransferases
    Mutation
    Stem Cell Factor
    Proto-Oncogene Proteins c-kit
    Ability testing
    Mast-Cell Leukemia
    Chemical activation
    Cells
    Apoptosis
    Imatinib Mesylate
    Cell Line
    Emitter coupled logic circuits
    Molecules
    Myeloid Leukemia
    Myeloid Cells
    Granulocyte-Macrophage Colony-Stimulating Factor
    Mast Cells
    Protein-Tyrosine Kinases

    ASJC Scopus subject areas

    • Hematology

    Cite this

    @article{ed2103b6d08847269f234f788cd50f06,
    title = "STI 571 inhibits the kinase activity of wild type and juxtamembrane C-kit mutants but not the exon 17 D816V mutation associated with mastocytosis",
    abstract = "STI 571 (formerly known as CGP 57148B), a 2-phenylaminopyrimidine derivative, is a known inhibitor of the the c-abl, bcr-abl, and platelet-derived growth factor receptor tyrosine kinases. This compound is currently being evaluated in clinical trials for the treatment of CML. We sought to extend the activity profile of STI 571 by testing its ability to inhibit the tyrosine kinase activity of mutant c-kit molecules associated with mastocytosis. We treated a human myeloid leukemia cell line (MO7e) that expresses wild-type c-kit protein with increasing doses of STI 571 prior to stimulation by Steel factor (SLF), the ligand for c-kit. SLF-induced c-kit autophosphorylation was effectively inhibited by STI 571 at concentrations of 0.1-10 u.M. The IC50 for inhibition of proliferation was 0.1-0.2 u.M. Additionally, we found that STI 571 blocked the anti-apoptotic activity of SLF. In contrast, the compound had no effect on cellular proliferation in response to GM-CSF. We also tested the activity of the compound using a human mast cell leukemia cell line (V560G HMC-1) that has an activating mutation of the juxtamembrane domain of c-kit (V560G). In V560G HMC-1 cells, STI 571 inhibited c-kit autophosphorylation, MAP kinase activation and Akt activation without altering total protein levels of c-kit, MAP kinase or Akt. The IC!0 for these effects was 0.01-0.1 U.M. The compound potently induced apoptosis (96.5{\%} apoptosis at l U.M STI 571 vs. 8.5{\%} in control cells). These results suggest that malignant mast cells are likely to be dependent upon the kinase activity of mutant c-kit molecules for proliferation and survival. However, most cases of human mastocytosis are associated with the activating mutations of the TK2 domain (D816V) rather than the juxtamembrane domain. In contrast to the results with wild type or V560G c-kit isoforms, STI 571 was unable to inhibit the kinase activity of the D816V mutant ckit (ICSO>5 U.M). Based on these studies, STI 571 would be predicted to be ineffective in the treatment of most patients with mastocytosis.",
    author = "Michael Heinrich and Wait, {Cecily L.}",
    year = "2000",
    language = "English (US)",
    volume = "96",
    journal = "Blood",
    issn = "0006-4971",
    publisher = "American Society of Hematology",
    number = "11 PART II",

    }

    TY - JOUR

    T1 - STI 571 inhibits the kinase activity of wild type and juxtamembrane C-kit mutants but not the exon 17 D816V mutation associated with mastocytosis

    AU - Heinrich, Michael

    AU - Wait, Cecily L.

    PY - 2000

    Y1 - 2000

    N2 - STI 571 (formerly known as CGP 57148B), a 2-phenylaminopyrimidine derivative, is a known inhibitor of the the c-abl, bcr-abl, and platelet-derived growth factor receptor tyrosine kinases. This compound is currently being evaluated in clinical trials for the treatment of CML. We sought to extend the activity profile of STI 571 by testing its ability to inhibit the tyrosine kinase activity of mutant c-kit molecules associated with mastocytosis. We treated a human myeloid leukemia cell line (MO7e) that expresses wild-type c-kit protein with increasing doses of STI 571 prior to stimulation by Steel factor (SLF), the ligand for c-kit. SLF-induced c-kit autophosphorylation was effectively inhibited by STI 571 at concentrations of 0.1-10 u.M. The IC50 for inhibition of proliferation was 0.1-0.2 u.M. Additionally, we found that STI 571 blocked the anti-apoptotic activity of SLF. In contrast, the compound had no effect on cellular proliferation in response to GM-CSF. We also tested the activity of the compound using a human mast cell leukemia cell line (V560G HMC-1) that has an activating mutation of the juxtamembrane domain of c-kit (V560G). In V560G HMC-1 cells, STI 571 inhibited c-kit autophosphorylation, MAP kinase activation and Akt activation without altering total protein levels of c-kit, MAP kinase or Akt. The IC!0 for these effects was 0.01-0.1 U.M. The compound potently induced apoptosis (96.5% apoptosis at l U.M STI 571 vs. 8.5% in control cells). These results suggest that malignant mast cells are likely to be dependent upon the kinase activity of mutant c-kit molecules for proliferation and survival. However, most cases of human mastocytosis are associated with the activating mutations of the TK2 domain (D816V) rather than the juxtamembrane domain. In contrast to the results with wild type or V560G c-kit isoforms, STI 571 was unable to inhibit the kinase activity of the D816V mutant ckit (ICSO>5 U.M). Based on these studies, STI 571 would be predicted to be ineffective in the treatment of most patients with mastocytosis.

    AB - STI 571 (formerly known as CGP 57148B), a 2-phenylaminopyrimidine derivative, is a known inhibitor of the the c-abl, bcr-abl, and platelet-derived growth factor receptor tyrosine kinases. This compound is currently being evaluated in clinical trials for the treatment of CML. We sought to extend the activity profile of STI 571 by testing its ability to inhibit the tyrosine kinase activity of mutant c-kit molecules associated with mastocytosis. We treated a human myeloid leukemia cell line (MO7e) that expresses wild-type c-kit protein with increasing doses of STI 571 prior to stimulation by Steel factor (SLF), the ligand for c-kit. SLF-induced c-kit autophosphorylation was effectively inhibited by STI 571 at concentrations of 0.1-10 u.M. The IC50 for inhibition of proliferation was 0.1-0.2 u.M. Additionally, we found that STI 571 blocked the anti-apoptotic activity of SLF. In contrast, the compound had no effect on cellular proliferation in response to GM-CSF. We also tested the activity of the compound using a human mast cell leukemia cell line (V560G HMC-1) that has an activating mutation of the juxtamembrane domain of c-kit (V560G). In V560G HMC-1 cells, STI 571 inhibited c-kit autophosphorylation, MAP kinase activation and Akt activation without altering total protein levels of c-kit, MAP kinase or Akt. The IC!0 for these effects was 0.01-0.1 U.M. The compound potently induced apoptosis (96.5% apoptosis at l U.M STI 571 vs. 8.5% in control cells). These results suggest that malignant mast cells are likely to be dependent upon the kinase activity of mutant c-kit molecules for proliferation and survival. However, most cases of human mastocytosis are associated with the activating mutations of the TK2 domain (D816V) rather than the juxtamembrane domain. In contrast to the results with wild type or V560G c-kit isoforms, STI 571 was unable to inhibit the kinase activity of the D816V mutant ckit (ICSO>5 U.M). Based on these studies, STI 571 would be predicted to be ineffective in the treatment of most patients with mastocytosis.

    UR - http://www.scopus.com/inward/record.url?scp=33748522353&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=33748522353&partnerID=8YFLogxK

    M3 - Article

    VL - 96

    JO - Blood

    JF - Blood

    SN - 0006-4971

    IS - 11 PART II

    ER -