Imatinib (STI571)S2475

In vitro assays for inhibition of a panel of tyrosine and serine/threonine protein kinases show that Imatinib inhibits the v-Abl tyrosine kinase and PDGFR potently with an IC50 of 0.6 and 0.1 μM, respectively. ^[1] Imatinib inhibits the SLF-dependent activation of wild-type c-kit kinase activity with a IC50 for these effects of approximately 0.1 μM, which is similar to the concentration required for inhibition of PDGFR. ^[2] Imatinib exhibits growth-inhibitory activity on the human bronchial carcinoid cell line NCI-H727 and the human pancreatic carcinoid cell line BON-1 with an IC50 of 32.4 and 32.8 μM, respectively. ^[3] A recent study shows that Imatinib has the potential to exert its antileukemia effects in chronic myelogenous leukemia by down-regulating hERG1 K(+) channels, which are highly expressed in leukemia cells and appear of exceptional importance in favoring leukemogenesis. ^[4]