サイトカインで活性化されるヒト骨髄性白血病細胞のシグナル伝達と機能 臨床検体を用いた検討

Abstract

We investigated tyrosine phosphorylation of proteins in primary human acute myelogenous leukemia (AML) cells stimulated by cytokines (G-CSF, GM-CSF, TNF, M-CSF, IL-3 and SCF) .These cytokines induced protein tyrosine phosphorylation in 14-17 cases out of total 18 cases tested, except that M-CSF induced this response only in 9 cases. In the present study, we observed cytokine-specific pattern of tyrosine phosphorylation of proteins in all cases. GM-CSF and IL-3 induced tyrosine phosphorylation of p92, p80, p70 and p42. In addition to these proteins, p95 was specifically tyrosine-phosphorylated by G-CSF in most of G-CSF-responsive cases. SCF induced tyrosine phosphorylation of p140-200, p110, p95, p60, p55 and p42, and M-CSF induced tyrosine phosphorylation of p140-200, p110 and p42. On the other hand, TNF exclusively induced tyrosine phosphorylation p42. p92 was identified as c-fes product in some cases, but was found to be STAT 5 in the other cases. p95 was identified as vav product in all cases tested. p42 and p140-200 (in M-CSF stimulation) was identified as microtubule-associated protein kinase and c-fms product, respectively.Respiratory burst activity of abnormal neutrophils in patients with myeloproliferative disorders such as chronic myelogenous leukemia was also investigated. In these patients, superoxide-producing capacity of neutrophils was markedly increased as compared with normal neutrophils. This phenomenon was observed only when neutrophils were stimulated with receptor-mediated agonists to release superoxide, and superoxide release induced by phorbol ester was normal in patients. In addition, in vitro responsiveness of patient neutrophils to cytokines was decreased. These findings suggest in vivo priming and activation of neutrophils by cytokines or via related mechanism in patients with myeloproliferative disorders.