ITR­284 modulates cell differentiation in human chronic myelogenous leukemia K562 cells.

ITR­284 is a carboxamide analog that can inhibit proliferation in human promyelocytic leukemia HL-60 cells. To understand the effects and molecular mechanisms of ITR­284 in human erythromyeloblastoid leukemia, we treated K562 cells with different concentrations of ITR­284 (0, 2, 4, 6, 8 and 10 nM) and all-trans retinoic acid (ATRA) (0, 0.1, 0.5, 1, 5 and 10 µM) for 24 h. The IC50 of ITR­284 was ~10 nM in K562 cells treated for 24 h as determined by MTT assay. May-Grünwald-Giemsa staining and nitro blue tetrazolium (NBT) assays were used to determine cell morphology changes and differentiation after ITR­284 and ATRA treatment. In addition, mRNA expression levels of hematopoietic factors, including GATA­1, NF-E2 and GATA­2, were elevated, while expression levels of BCR­ABL were downregulated in K562 cells after 24 h of treatment with ITR­284 as determined by quantitative reverse transcription polymerase chain reaction. In addition, western blot analyses showed that FOXM1, GLI 1 and c-MYC protein levels were decreased by ITR­284. Taken together, our data show that ITR­284 induced K562 cell differentiation, which led to decreased tumorigenesis. Our findings suggest that ITR­284 could be a potential candidate for treating chronic myelogenous leukemia.