FAS and colorectal carcinoma: These two pathways eventually trigger the activation of caspase-3, enzymatic hydrolysis of apoptotic protease substrates, leading to apoptosis.58 In our study, western blot analysis showed that in the two tested CRC cell lines shikonin induced an increase of expression of Fas, FasL, cytochrome c and Bax and led to the cleaved of PARP and caspases (Figure 4A-C).