Growth suppression of human mast cells expressing constitutively active c-kit receptors by JNK inhibitor SP600125.
Activation of c-jun N-terminal kinase (JNK) through c-kit-mediated phosphatidylinositol 3 (PI3) and Src kinase pathways plays an important role in cell proliferation and survival in mast cells. Gain-of-function mutations in c-kit are found in several human neoplasms. Constitutive activation of c-kit has been observed in human mastocytosis and gastrointestinal stromal tumor. In the present study, we demonstrate that an anthrapyrazole SP600125, a reversible ATP-competitive inhibitor of JNK inhibits proliferation of human HMC-1 showed constitutive activation of JNK/c-Jun, and the inhibitory effect of SP600125 on cell proliferation was associated with cell cycle arrest at the G1 phase and apoptosis accompanied by the cleavage of caspase-3 and PARP. Caspase-3 inhibitor Z-DEVD-FMK almost completely inhibited SP600125-induced apoptosis of HMC-1 cells. In contrast, caspase-9 inhibitor Z-LEHD-FMK failed to block SP600125-induced apoptosis. Following Sp600125 treatment, down-regulation of cyclin D3 protein expression, but not p53 was also observed. Thus, JNK/c-Jun is essential for proliferation and survival of HMC-1 cells. The results obtained from the present study suggest the possibility that JNK/c-Jun may be a therapeutic target in diseases associated with mutations in the catalytic domain of c-kit.
Wang
Bin
B
The First Department of Internal Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
Tsukada
Junichi
J
Higashi
Takehiro
T
Mizobe
Takamitsu
T
Matsuura
Ai
A
Mouri
Fumihiko
F
Sawamukai
Norifumi
N
Ra
Chisei
C
Tanaka
Yoshiya
Y
D000873:Anthracenes / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D056743:Cyclin D3; D016213:Cyclins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors*; D008407:Mast Cells / Q000166:cytology* / Q000187:drug effects*; D010766:Phosphorylation / Q000187:drug effects; D016755:Proto-Oncogene Proteins c-jun / Q000037:antagonists & inhibitors; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism*; D013997:Time Factors
D000873:Anthracenes; C534696:CCND3 protein, human; D056743:Cyclin D3; D016213:Cyclins; D016755:Proto-Oncogene Proteins c-jun; C432165:pyrazolanthrone; D019009:Proto-Oncogene Proteins c-kit; D048031:JNK Mitogen-Activated Protein Kinases; D053148:Caspase 3; D053453:Caspase 9