5-Ethynyl-20-deoxyuridine (EdU) assay

Cells were plated in 24-well plates (5 × 10⁴ cells/well). Then the media was supplemented with 50-mM EdU solution. 24 h later, the cells were fixed and permeabilized. Cell proliferation was detected using the EdU assay kit (RiboBio). The images were visualized with a fluorescence microscope. Finally, cells stained with EdU in five randomly chosen fields were counted.