Figure 2

Inhibition abilities and chemosensitizing effects of helenalin, BHM, and BHG on ABC transporters in ABCB1 or ABCG2 overexpressing cells. (a,b) The intracellular calcein and hoechst33342 fluorescence were increased under helenalin, BHM, or BHG 30 min treatments in ABCB1/HEK293 cells and ABCG2/HEK293 cells. (c–e) The synergistic cytotoxicity of helenalin, BHM, or BHG co-treated with docetaxel and doxorubicin indicated that helenalin, BHM, or BHG increased sensitivity to the chemotherapeutics docetaxel and doxorubicin in ABCB1/HEK293 cells and ABCG2/HEK293 cells. (f–g) The MDR preventive effects of helenalin, BHM, and BHG in MDA/doc cells. Synergy assessment of helenalin, BHM, and BHG in combination with doxorubicin or docetaxel in ABCB1/HEK293 (h) and ABCG2/HEK293 (i) cell lines. Synergy scores were interpreted as follows: <−10, antagonism; −10 to 10, additive effect; >10, synergism. Statistical differences were evaluated by the ANOVA followed by post hoc analysis (Tukey’s test). * denotes p < 0.05 as compared to doxorubicin or docetaxel alone treatments. Each data is expressed as the mean ± standard error of at least two experiments, each performed in duplicate.