Analysis of apoptosis of HepG2 cells upon treatment with TET or HCPT followed by PI staining, using a flow cytometer (A) Control; (B) HCPT (7 μmol/L); (C) TET (3.75 μmol/L); (D) TET (7.5 μmol/L); and (E) TET (15 μmol/L).