resveratrol-4--o-glucuronide and Colonic-Neoplasms

The cytotoxic and genotoxic potential of phase II metabolites of resveratrol (RSV) was investigated in human colon cells with special emphasis on human topoisomerase (TOP) II.. Cell-free screening of topoisomerase II (TOPII) inhibition by the decatenation assay showed inhibitory potential for RSV (≥200 μM) and for the first time for the three human phase II metabolites RSV-3-sulfate (≥200 μM), RSV-3-glucuronide (≥100 μM) and RSV-disulfate (≥100 μM). Conjugation at the C4'-position (RSV-4'-sulfate and RSV-4'-glucuronide) resulted in loss of the inhibitory potential in this assay. Cell-based experiments with RSV and the most abundant metabolite in humans, RSV-3-Sulf, revealed no TOP poisoning in HT29 and Caco-2 cells up to 250 μM. Further, the phase II metabolite exhibited only minor effects in the comet assay and showed negligible cytotoxic effects and apoptotic potential after 1 and 24 h incubation. Fluorescence microscopy and HPLC-DAD analysis identified cellular uptake of RSV and of RSV-3-Sulf although to a lesser extent when compared to RSV. Furthermore, within the cells fractional deconjugation of RSV-3-Sulf to the parent compound was observed.. Sulfate- and glucuronide-phase II metabolites might contribute to the genotoxic potential of RSV by inhibition of TOPII activity. By deconjugation at the target site RSV-3-Sulf might serve as a pool of the parent compound.

Topics: Apoptosis; Caco-2 Cells; Cell-Free System; Colonic Neoplasms; Comet Assay; Drug Screening Assays, Antitumor; Glucuronides; HT29 Cells; Humans; Resveratrol; Stilbenes; Topoisomerase II Inhibitors

Resveratrol (RSV) has been proposed to prevent tumor growth; nevertheless, these preventive effects are controversial since RSV pharmacokinetics studies show a low bioavailability. Recent clinical trials show that patients with colorectal cancer and receiving oral RSV have high levels of RSV conjugates in the colorectum, mainly RSV-3-O-sulfate (R3S), RSV-3-O-glucuronide, and RSV-4'-O-glucuronide. However, their potential biological activity has not yet been established. This study thus investigated in human colorectal cancer cell lines whether RSV main metabolites retain anticarcinogenic properties as their parental molecule.. Proliferation, apoptosis assays and cell cycle analysis were performed to study the effect of RSV, R3S, RSV-3-O-glucuronide, or RSV-4'-O-glucuronide alone or of a mixture of the three metabolites. R3S inhibits colon cancer cells proliferation and an accumulation of cells in S phase. Interestingly, the mixture induced a synergistic effect. This process was associated with an induction of DNA damages and apoptotic process, which allowed sensitization of colon cancer cells to the anticancer drugs.. Altogether, our data provide significant new insight into the molecular mechanism of RSV and support the notion that despite low bioavailability in vivo, RSV biological effects could be mediated by its metabolites.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cell Survival; Colonic Neoplasms; Drug Synergism; Glucuronides; Humans; Resveratrol; Stilbenes

Resveratrol is a plant-derived polyphenol with chemotherapeutic properties in animal cancer models and many biochemical effects in vitro. Its bioavailability is low and raises the possibility that the metabolites of resveratrol have biological effects. Here we investigate the actions of resveratrol 3-O-D-glucuronide, resveratrol 4-O-D-glucuronide, and resveratrol 3-O-Dsulfate on the growth of colon cancer cells in vitro.. The growth of Caco-2, HCT-116, and CCL-228 cells was measured using the neutral red and MTT assays. Resveratrol and each metabolite inhibited cell growth with IC50 values of 9.8–31 μM. Resveratrol caused S phase arrest in all three cell lines. Resveratrol 3-O-D-glucuronide and resveratrol 4-O-D-glucuronide caused G1 arrest in CCL-228 and Caco-2 cells. Resveratrol 3-O-D-sulfate had no effect on cell cycle. Growth inhibition was reversed by an inhibitor of AMP-activated protein kinase (compound C) or an adenosine A3 receptor antagonist (MRS1191). The A3 receptor agonist 2Cl-IB-MECA inhibited growth and A3 receptors were detected in all cell lines. The resveratrol glucuronides also reduced cyclin D1 levels but at higher concentrations than in growth experiments and generally did not increase phosphorylated AMP-activated protein kinase.. Resveratrol glucuronides inhibit cell growth by G1 arrest and cyclin D1 depletion, and our results strongly suggest a role for A3 adenosine receptors in this inhibition.

Topics: Adenosine A3 Receptor Antagonists; AMP-Activated Protein Kinases; Apoptosis; Caco-2 Cells; Cell Line, Tumor; Cell Proliferation; Cell Survival; Colonic Neoplasms; Cyclin D1; G1 Phase Cell Cycle Checkpoints; Glucuronides; Hemolysis; Humans; Receptor, Adenosine A3; Resveratrol; Stilbenes