4βHWE-induced apoptosis in H1299 cells. Cells were administered with or without 5 μg/mL of 4βHWE for 24 h. (A) The determination of sub-G1 DNA content in H1299 cells by flow cytometry. (B) Apoptosis detection by Annexin V flow cytometry. (C-F). The apoptotic phenotype detected by Annexin V/PI double staining was found in (D, F) 4βHWE-treated cells rather than in vehicle (C, E), respectively. Original magnification: × 200.