Metamizole limits proliferation in chronic myeloid leukemia cells and triggers apoptosis via the bax/bcl-2/caspase-3 cascade

Metamizole is a controversial non-steroidal anti-inflammatory drug because it may cause agranulocytosis usually in long-term use. It may reduce proliferation while increasing apoptosis in some cancer cells. In our study, the effects of increasing concentrations of metamizole on chronic myeloid leukemia (CML) cell line K562 were evaluated in terms of proliferation and apoptosis. K562 cells were cultured with 1,10,50,100 µM concentrations of metamizole in addition to the control group. The effect on cell proliferation was determined by MTT and analysis of mitotic cell counts. The apoptotic effects were analyzed by flow cytometry using Annexin V/Propidium iodide, ELISA for caspase-3 concentrations, and RT-qPCR for Bax-Bcl-2 mRNA expression levels. Evaluations were performed for 24 and 48 h of exposure. MTT assay revealed that metamizole limited the proliferation of cells at 10 µM concentration. Caspase-3 concentrations increased in cells exposed to concentrations of 50 µM and above. Flow cytometry results obtained using Annexin V/PI showed that especially 50 and 100 µM concentrations promoted apoptosis compared to the control. Bcl-2 mRNA expression was also significantly decreased at concentrations of 50 and 100 µM, while Bax mRNA expression was significantly increased only for 100 µM. Mitotic cell numbers also decreased with increasing concentrations. The known adverse effect of metamizole, agranulocytosis, suggests it may negatively affect cell proliferation. In this study, metamizole had both antiproliferative and pro-apoptotic effects on K562. The results of our study indicate that the synergistic effects of metamizole in the treatment of CML, especially in cases resistant to tyrosine kinase inhibitors, should be evaluated with further studies under in vitro and in vivo conditions.