CYCS and cancer: Furthermore, the absence of cell death/cytotoxicity in ALI multilayered co-cultures exposed to the four anti-cancer agents was correlated to a complete lack in: (i) caspases 1–10 activation (Fig. 3b), (ii) release of cytochrome c (Fig. 3c), and (iii) subsequent activation of procaspase-3 and PARP into their active cleaved forms (Fig. 3d).