2.10. Apoptosis assay

Apoptosis was assessed by Annexin V‐FITC (BD Biosciences Pharmingen, San Diego, CA, USA) dual staining. After drug treatment, cells were harvested by trypsinization. The cells were washed with ice‐cold PBS and then washed with 1× binding buffer. Cells were then labeled with Annexin V‐FITC according to the manufacturer's instructions. Apoptotic cells were analyzed using a BD FACSVerse flow cytometer (Becton Dickinson Immunocytometry Systems). For TUNEL assays, cells were seeded on glass coverslips in six‐well plates and treated with drugs. After treatment, cells were fixed with 4% PFA and analyzed using the In Situ Cell Death Detection Kit (Roche Diagnostics, Mannheim, Germany). Apoptotic cells were detected according to the manufacturer's instructions. Slides were visualized with a Zeiss AxioVert 200 inverted epifluorescence microscope. Images were captured with an AxioCam digital microscope camera and analyzed with AxioVision software (Carl Zeiss Vision, Oberkochen, Germany).