(a) Immunoblot analysis of apoptotic signaling proteins in HepG2 cells transfected with pcDNA, or pcDNA–TK–NTR, or pcDNA–TK–p53–NTR by PLGA–PEG–PEI nanoparticles with SP94 targeting peptide and treated with GCV, CB1954, or GCV plus CB1954 prodrugs for 72 h, and (b) its quantitative representation. (c) DNA fragmentation assay of cells harvested after 72 h of treatment.