Src family kinases promote AML cell survival through activation of signal transducers and activators of transcription (STAT).

We investigated the role of Src family kinases (SFKs) in the regulation of STAT activation in myeloid leukemia cells. Two of 6 AML cell lines displayed constitutive STAT5 activation, whereas four cell lines had constitutive SFK activity. Treatment with the SFK inhibitors suppressed STAT5 activation and decreased viability. Akt phosphorylation and Mcl-1 expression decreased after SFK inhibition accompanied by apoptosis induction. In primary AML specimens, SFK inhibitors suppressed proliferation in 5 of 14 specimens. These data indicate that Src-STAT5 and Src-Akt pathways are integral survival signal pathways in AML cells. Src inhibition may represent a novel treatment strategy for investigation in AML.