Molecular mechanisms involved in the cytotoxicity induced by coumarins from Calophyllum brasiliense in K562 leukaemia cells

Objectives: The aim of this study was to determine the cellular and molecular mechanisms of cell death induced by mammea A/BA and A/BB (3 : 1) on K562 cells.

Methods: These compounds were isolated from Calophyllum brasiliense and its cytotoxicity was tested using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell death was evaluated by Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and immunocytofluorescence of active caspase-3. Genotoxicity was tested using comet assay. Lastly, a chemoinformatic analysis was performed with Osiris-Molinspiration software.

Key findings: The mixture of mammea A/BA and A/BB (3 : 1) showed cytotoxic activity against K562 cells (IC50 = 43.5 μm). TUNEL positive cells and active caspase-3 were detected after treatment. Genotoxicity of mammea A/BA and A/BB on K562 was detected since first hour of treatment. Additionally, mammea A/BA and A/BB were found to be in compliance with Lipinski 'rule of 5' suggesting that they possess strong potential of druglikeness.

Conclusions: The overall results confirm and extend the knowledge about coumarins as an important resource of antitumor drugs, and indicate that these compounds could be used in further preclinical studies against leukaemia.