Apoptosis-inducing factor and caspase-dependent apoptotic pathways triggered by different grape seed extracts on human colon cancer cell line Caco-2

Consumption of grape seed extract (GSE) is widely marketed as a dietary supplement and is considered safe for human health. Nevertheless, theanalytical composition of GSE from different grape cultivars, growing in special agronomic constraints, differs greatly in flavan-3-ols content.The major concern with GSE studies is a lack of availability of uniformly standardised preparations, which raises an important question whetherdifferent GSE samples have comparable activity and trigger the same mechanisms of action on a given biological system. Therefore, it is temptingto speculate that GSE, obtained from different cultivars, could exert differentiated anticancer effects. The focus of the present study is to determinethe selective biological efficacy of GSE obtained from three different sources on the human colon cancer cell line Caco-2. Irrespective of its source,high doses of GSE induced a significant inhibition on Caco-2 cell growth. Moreover, apoptosis was enhanced through both caspase-dependent andcaspase-independent mechanisms, leading to an early apoptosis-inducing factor release and, further, to a dramatic increase in caspase 7 and 3activity. However, a significant difference in apoptotic rates induced by the three grape sources clearly emerged when treating cancer cellswith low and intermediate GSE concentrations (25 and 50mg/ml).Grape seed extracts: Apoptosis-inducing factor: Apoptosis: Flavan-3-ols