Fig. 4

Chemotherapeutic drug-induced expression of ACE2 in breast cancer cells is ROS-dependent. A Low-dose chemotherapeutic drugs induce generation of ROS in breast cancer cells. MDA-468, T47D, MCF-7 and MDA-231 cells were treated with 0.05 µM EPI, 500 µM NAC, 0.05 µM EPI + 500 µM NAC at 37 °C for 72 h or 100 µM H₂O₂ for 4 h. Intracellular ROS levels were measured by flow cytometry using a Reactive Oxygen Species Assay Kit. The levels of ROS are summarized in the histogram on the right. B Western blot and C qRT-PCR analysis showed ACE2 expression in MDA-468, MDA-231, MCF-7 and T47D cells after exposure to EPI, NAC H₂O₂ or EPI + NAC. All data are shown as mean ± SD; *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, and ns P > 0.05 versus control