BackgroundResveratrol (3,4’,5-trihydroxystilbene), a stilbenoid isolated from many species of plants, is widely known for its antioxidative, anti-inflammatory, immunomodulatory and anticancer activities. Recently, novel resveratrol oligomers have been isolated from various plants; their diverse structures are characterized by the polymerization of two or more resveratrol units. Little is known regarding the anticancer and immunomodulating activities of these oligomers. In this study, we designed in vitro models to compare resveratrol side by side with its natural dimer NBT-167 for their anticancer and immunological activities.MethodsWe isolated resveratrol and its dimer (NBT-167) from plants. The potency of the compounds was compared side by side using cancer cell survival assays and immunological assays with various types of human cells including cancer cell lines, PBMCs and enriched NK, gamma delta T cells, THP-1 monocytic cells, HL-60 promyelocytic leukemia cells as well as mouse RAW264.7 macrophages.ResultsNBT-167 was found to be more potent than resveratrol in inhibiting growth of various cancer cells and modulation of cytokine production from anti-IgM, LPS, PHA or SEB stimulated PBMC. Both compounds similarly enhanced IL-2 stimulated NK and gamma delta T cell killing activity against K562 cells and modulated nitric oxide production from LPS/IFN-g induced RAW264.7 macrophages and phagocytotic activity of HL-60 cells. NBT-167 was slightly more potently than resveratrol in inhibiting chemotaxis of HL-60 cells and blocking cell cycle of THP-1 and HL-60 cells at G1/S transition. In addition, NBT-167, but not resveratrol, could increase IL-2 production and T cell proliferation stimulated with anti-CD3 and anti-CD28 and synergize with anti-PD-1 antibody to increase IL-2 and IFN-gamma production in co-culture of allotypic T cells and dendric cells (MLR).ConclusionsOur data showed that NBT-167, a dimer of resveratrol, had anticancer and immunomodulatory activities such as modulation of expression of cytokines in immune cells and induction of cancer cell-killing activities of NK and gamma delta T cells. Generally, NBT-167 appeared to have higher activities than resveratrol in modulating immune cells and inhibiting cancer cells. NBT-167 could be a promising cancer immunotherapeutic agent targeting both cancer cells and immune cells.
T-cell killing of primary follicular lymphoma cells is dramatically potentiated by GA101, a type II glycoengineered anti-CD20 monoclonal antibody