P6 NPs enhancement of toxicity to various tumor types through the augmentation of apoptosis. (a, b) In vitro cytotoxicity of cells treated with cisplatin, P6 NPs, or P6 Soln for (a) 48 or (b) 72 h. (c, d) In vitro apoptosis of (c) A2780 and (d) A2780cis cells treated with cisplatin, P6 NPs, or P6 Soln for 24 h.