The Effect of BCR-ABL Specific Tyrosine Kinase Inhibitors on the Thioredoxin System in Chronic Myeloid Leukemia

Abstract

Chronic myeloid leukemia (CML) is a myeloproliferative disorder that is caused by the formation of a fusion onco-protein, BCR-ABL. Since BCR-ABL plays a role in the progression of CML, the most common treatments of CML are tyrosine kinase inhibitors (TKIs) that specifically target BCR-ABL. However, resistance to TKIs is a major problem in CML treatment. A promising target in overcoming drug resistance in other cancers is the thioredoxin (TRX) system, an antioxidant system that maintains cellular redox homeostasis. The TRX system is upregulated in many cancers and this is associated with a poor prognosis. Analysis of a patient database showed that the expression of the TRX system was upregulated in CML patients compared to healthy donors. Our experiments revealed a significant link between the TRX and BCR-ABL systems since inhibition of BCR-ABL with chemical inhibitors and siRNA resulted in a decrease in the activity and expression of the TRX system in CML cells. This is notable as it shows that the TRX system may be a viable target in the treatment of CML.