Involvement of mitochondria and recruitment of Fas/CD95 signaling in lipid rafts in resveratrol-mediated antimyeloma and antileukemia actions.

We have found that resveratrol (trans-3,4',5-trihydroxystilbene) induced apoptosis in multiple myeloma (MM) and T-cell leukemia cells through coclustering of Fas/CD95 death receptor and lipid rafts, whereas normal lymphocytes were spared. Tumor necrosis factor-related apoptosis-inducing ligand receptors, Fas-associated death domain-containing protein (FADD), procaspase-8, procaspase-10, c-Jun amino-terminal kinase and Bid were also recruited into lipid rafts on resveratrol incubation with MM and T-cell leukemia cells. Raft disruption inhibited resveratrol-induced apoptosis. Bcl-XL overexpression prevented resveratrol-induced disruption of mitochondrial transmembrane potential (DeltaPsi(m)) and apoptosis. A FADD dominant-negative mutant, that blocked Fas/CD95 downstream signaling, precluded resveratrol-induced DeltaPsi(m) loss and apoptosis, indicating a sequence of Fas/CD95 signaling-->mitochondrion in the apoptotic response triggered by resveratrol. Cells deficient in Fas/CD95 did not undergo resveratrol-induced apoptosis. Pretreatment of MM cells with interferon-gamma upregulated Fas/CD95 and caspase-8, and potentiated resveratrol-induced apoptosis. Our data indicate that recruitment of Fas/CD95 death receptor and downstream signaling molecules into lipid rafts, followed by DeltaPsi(m) disruption, underlies the apoptotic action of resveratrol in MM and T-cell leukemic cells. Combination of resveratrol with perifosine or bortezomib potentiated the apoptotic response induced by each single drug. These results also highlight the role of recruitment of Fas/CD95 signaling in lipid rafts in antimyeloma and antileukemia chemotherapy.