Oncogene
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BCR/ABL fusion tyrosine kinase is responsible for the initiation and maintenance of the Philadelphia chromosome (Ph(1))-positive chronic myelogenous leukemia (CML) and a cohort of acute lymphocytic leukemias (ALL). STI571 (Gleevec), a novel anti-leukemia drug targeting BCR/ABL kinase can induce remissions of the Ph(1)-positive leukemias. STI571 was recently combined with the standard cytostatic drugs to achieve better therapeutic results and to overcome emerging drug resistance mechanisms. ⋯ Single colony RT-PCR assay showed that colonies arising from the mixture of CML cells and normal bone marrow cells after treatment with STI571+WT were selectively depleted of BCR/ABL-positive cells. Biochemical analysis of the CML cells after the treatment revealed that combination of STI571+WT caused a more pronounced activation of caspase-3 and induced massive apoptosis, in comparison to STI571 and WT alone. In conclusion, combination of STI571+WT or STI571+LY may represent a novel approach against the Ph(1)-positive leukemias.