Genotoxicidade da combinação dos antimaláricos lumefantrina e artemeter em linfócitos humanos

Abstract

Currently, the artemisinin combination therapies (ACT) are the strategy recommended by the World Health Organization for the treatment of malaria, a disease that affects millions of people worldwide. The combination of lumefantrine plus artemether (LA, at 6:1 ratio) is widely used as the first line of treatment for children and adults. Although it has been demonstrated that both lumefantrine (LF) and artemether (AR) present genotoxic activity, there are no studies reporting the genotoxicity of these combined drugs in human cells. The aim of this study was to evaluate the genotoxic effects of the LA combination on human lymphocytes in vitro and if the treatments induce DNA damage by oxidation and/or alkylation, as well as verify the potential of this treatment to generate reactive oxygen species (ROS). A fixed concentration of LF (40.0 μg/mL) was tested in combination with different concentrations of AR (6.7 μg/mL, 20 μg/mL and 40 μg/mL), generating drug combinations at 6: 1, 6: 3 and 6: 6 ratios, respectively. The comet assay was used for the analysis of total DNA damage, the modified version with the formamidopyrimidine DNA glycosylase (FPG) enzyme was used to evaluate DNA damage by oxidation and/or alkylation and intracellular ROS production was measured by flow cytometry. All treatments isolated (LF40=14.76±1.94, AR6.7=9.44±1.59, AR20=12.69±2.33 and AR40=15.44±2.39), as well as the combinations tested (LF40:AR6.7=15.30±2.52; LF40:AR20=18.70±4.78 and LF40:AR40=29.01±5.16) increased total DNA damage in relation to the negative control (4.55±1.25, p <0.05). The drugs present an antagonistic effect on total DNA damage (analyzed by the combination index, CI), which decreased as the proportion of artemether in the combination increased (CI = 1.58, 1.46 and 1.04, for the proportions 6:1, 6:3 and 6:6, respectively). On the other hand, the levels of DNA damage by oxidation and/or alkylation was similar between treatments (p=0.28), as well as the levels of intracellular ROS (p=0.42). In conclusion, the data presented in this study demonstrated that the combination LA is genotoxic for human lymphocytes in vitro and that these drugs in combination interact in an antagonistic manner, but both the isolated drugs and the LA combination do not elevate intracellular oxidative stress nor cause damage by oxidation and/or alkylation in DNA.