Evaluation of Cytotoxic and Apoptotic Effects of DT386–BR2: A Promising Anticancer Fusion Protein

Purpose: In the previous studies, we designed an anticancer immunotoxin containing the catalytic and translocation domains of diphtheria toxin fused to BR2, a buforin II-derived antimicrobial peptide as a cancer-specific cell penetrating peptide, in order to target various cancer cells. The aim of this study was to evaluate the in vitro cytotoxicity of DT386–BR2 against K-562 cells as the most famous cell line for leukemia. Materials and Methods: MTT and flow-cytometry assays were used for determining the cytotoxic effects and cell death mechanism of DT386–BR2, respectively, against K-562 cell line. The recombinant DT386 and synthetic BR2 were used as the negative control in cytotoxicity assay. Results: The results of this study showed a significant reduction in survival of K-562 cells caused by DT386– BR2 as compared with BR2 and DT386 fragments. On the contrary, the flow-cytometry results showed apoptosis induction by DT386–BR2 after 12 h in a dose- and time-dependent manner. Conclusion: DT386–BR2 fusion protein can be used for further preclinical studies for determining its pharmacokinetic/ pharmacodynamic profiles and evaluating its anticancer efficacy in suitable animal models.