Determination of the apoptotic effect and molecular docking of benzamide derivative XT5 in K562 cells.

BACKGROUND: The tyrosine kinase inhibitor imatinib used as a first line treatment in chronic myeloid leukemia (CML) patients, may lead to resistance and failure to therapy. Novel combinations of imatinib with other drugs is a strategy to improve treatment efficiency.

OBJECTIVE: In this study, the antileukemic and apoptotic effects of a benzamide derivative XT5 and benzoxazole derivative XT2B and their combination with imatinib were investigated in imatinib-sensitive (K562S) and imatinib-resistant (K562R) CML cells.

METHODS: In vitro cytotoxicity was determined by MTT assay. Then apoptotic effect of XT5 on CML cell lines was tested by Annexin V flow cytometry, caspase activation and RT-PCR. Docking calculation was performed using AutoDock Vina in PyMOL environment using AutoDock/Vina plugin for PyMOL.

RESULTS: According to our MTT assay data XT5 indicated significant antiproliferative effect on cell lines, therefore we investigated apoptotic effects of XT5. Treatment of K562 cell lines with XT5 and imatinib-XT5 combination, increased cytotoxicity, the Annexin V binding and caspase 3/7 activation. In addition to apoptosis determination assays we observed an increase in the expression levels of the pro-apoptotic (BAX, BAD and BIM) genes in XT5 treated K562R and K562S cells. Molecular modelling experiments showed that XT5 have hydrogen bonding interactions to important amino acids of BCR-ABL kinase receptor, however XT2B did not shown any hydrogen bond interactions.

CONCLUSION: Our results indicate that XT5 could be a potential candidate to be used as a new anticancer drug and XT5 combination with imatinib as an alternate treatment strategy for overcoming imatinib resistance.