Nanomolar level of resveratrol (trans-3,5,4'-trihydroxystilbene) is required, but is not sufficient, to inhibit the growth of human monocytoid tumor cells through an apoptotic-like mechanism

The chemopreventive activity of resveratrol, a stilbene found in grapes and wine, was evaluated in a human monocytic leukemia cell line at the same concentration (100 nM to 1 μM) as that found in the bloodstream after moderate wine intake. As early as at 4 h after intake, resveratrol exhibited antiproliferative and cytotoxic activity. At the same time, some apoptotic-like phenomena were detected such as cell membrane perturbation (phosphatidylserine-annexin V binding), apolipoprotein (APO)-1/FAS (CD95) expression and mitochondrial (ΔΨ) depolarization. The anticancer drug camptothecin, used as a positive control, did not significantly increase APO-1/FAS (CD95) levels, while only a modest increase in APO-1/FAS-CD95 ligand (CD95-L) was detected. At 12 h, however, resveratrol at concentrations of 100 nM and 1 μM did not exhibit the same antiproliferative activity and increased cell proliferation was correlated to a significant increase in FAS-L expression. We conclude that treatment with low doses of resveratrol, such as those found after moderate wine intake, is not sufficient to stop human leukemia cell line proliferation and that cell resistance, marked by high FAS-L (CD95-L) expression, could be mediated by low (ΔΨ) mitochondria-released antiapoptotic factors such as BCL-2. It is also suggested that the synergistic action of other wine components with resveratrol might, at least partially, explain its chemopreventive activity.