Arsenic trioxide and interferon alpha circumvent tyrosine kinase inhibitors resistance in chronic myeloid leukemia models -

Abstract

Background and Aims: Chronic myeloid leukemia (CML) is a myeloproliferative disorder characterized by t (9; 22) translocation that generates bcr-abl fusion gene coding for BCR-ABL oncoprotein with abnormal constitutive tyrosine kinase activity. Tyrosine kinase inhibitors (TKI) have been successfully established for the treatment of CML. Despite high rates of clinical response, CML patients can develop resistance against TKI mainly due to kinase domain mutations. Of special interest is T315I mutation, which accounts for 15–20percent of mutations affecting ABL kinase domain. T315I confers resistance to almost all TKI. Ponatinib, the only TKI effective against T315I single but not T315I-inclusive compound mutations, was suspended due to its cardiac side effects and is currently limited to specific cases. Recently, we demonstrated that arsenic trioxide (ATO) and interferon alpha (IFNα) inhibited proliferation, induced apoptosis, prolonged survival and affected leukemia initiating cells activity in wild-type bcr-abl CML models. Here, we investigate the effect of ATO and IFNα on the proliferation, cell cycle arrest and induction of apoptosis in imatinib-resistant CML cell lines and its anti-tumor activity in CML mouse model harboring the T315I mutation. Methods: Imatinib-resistant K562-R and Ar230-R CML cells were treated with different concentrations of ATO and IFNα. The effect of the treatment on cell proliferation was performed using MTT assay. Synergy analysis was calculated using the compusyn software. The effect of the treatment on cell cycle arrest and apoptosis was performed using PI assay, TUNEL assay and Rhodamine-123 assay, respectively. Using a retroviral bcr-abl T315I transduction murine CML model, we studied the effect of ATO-IFNα on the survival of leukemic mice harboring this famous mutation.Results: Our preliminary results demonstrated that ATO and IFNα synergized to inhibit the proliferation of imatinib-resistant CML cells. In addition, ATO-IFNα combination induce