Altogether, these results suggest that SN or C3/C2 could sensitize colon cancer cells to TRAIL by an anti-proliferative effect via induction of the cell cycle p21 inhibitor leading to a G0/G1 arrest and also by a pro-apoptotic effect via increased expression of DR5 and decreased expression of apoptosis inhibitors (XIAP, FLIPL). This evidence concerns the gene XIAP and colonic neoplasm.