Brusatol regressed the growth of HER2-positive SK-OV-3, BT-474, and SK-BR-3 cells by inhibiting Nrf2/HO-1 and HER2-AKT/ERK1/2 pathways. (a) BT-474, SK-OV-3, and SK-BR-3 cells were treated with brusatol in a dose range for 2 days. IC50 for BT-474, SK-OV-3, and SK-BR-3 were 0.7537 μM (95% confidence interval [CI], 0.6983–0.8136 μM), 0.7610 μM (95% CI, 0.6699–0.8646 μM), 8.631 μM (95% CI, 7.699–9.675 μM), respectively. Points, mean of 3 independent CCK-8 assays; bars, SD. (b) BT-474, SK-OV-3, and SK-BR-3 cells were treated with brusatol at 0, 1, 5, or 10 μM for 24 hours. The changes in Nrf2/HO-1 and HER2-AKT/ERK1/2 signaling pathways were monitored by western blotting.