Quercetin glucuronides inhibited 2-aminofluorene acetylation in human acute myeloid HL-60 leukemia cells.
ABSTRACT Our earlier study has demonstrated that following the exposure of rat to the arylamine carcinogen 2-aminofluorene, DNA-2-aminofluorene adducts were found in the target tissues liver, bladder, colon, lung and also in circulating leukocytes (lymphocytes and monocytes). The result also demonstrated that orally treated antioxidants decreased N-acetylation of 2-aminofluorene in target tissues and leukocytes. Therefore, this study investigated whether quercetin glucuronides could affect N-acetylation of 2-aminofluorene in human acute myeloid leukemia HL-60 cells. Evidence is presented here that human leukemia cells are capable of acetylating 2-aminofluorene. Quercetin glucuronides did inhibit 2-aminofluorene acetylation in intact cells. The results also indicated that quercetin glucuronides induced cytotoxicity in dose-dependent manner in the examined human acute myeloid leukemia HL-60 cells.
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ABSTRACT: Lung cancer is the leading cause of cancer death in many developed countries, including Taiwan. Quercetin, a widely distributed bioflavonoid, is well known to induce growth inhibition in a variety of human cancer cells. Quercetin glucuronides are the main circulating metabolites after dietary supplements with quercetin in humans. However, there is little information available as to how quercetin glucuronides affect human cancer cells. We investigated the effects of quercetin glucuronides in a human lung cancer cell line NCI-H209. We checked the cell viability, cell cycle checkpoint proteins, pro- and antiapoptotic proteins, caspase-3 activity, and gene expression by flow cytometry and Western blot. The viability of cells decreased in a dose- and time-dependent manner. Cell cycle analysis revealed a significant increase of the proportion of cells in G2/M phase and subG0/G1 phase (corresponding to apoptotic cells). Moreover, quercetin glucuronides increased the expressions of cyclin B, Cdc25c-ser-216-p, and Wee1 proteins, indicating the G2/M arrest. We also demonstrated a concurrent decrease of the mitochondrial membrane potential, release of cytochrome c, up-regulation of Bax, down-regulation of Bcl-2, and activation of caspase-3, and subsequently, cleavage of poly(ADP-ribose) polymerase. In addition, quercetin glucuronide-induced apoptosis was totally blocked by the broad-spectrum caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp fluoromethylketone. Taken together, we demonstrated that quercetin glucuronides inhibited proliferation through G2/M arrest of the cell cycle and induced apoptosis via caspase-3 cascade in the human lung cancer cell line NCI-H209. Delineation of the biological effects of specific major quercetin metabolites on chemotherapeutic potential or chemoprevention of human cancers warrants further investigation.Drug metabolism and disposition: the biological fate of chemicals 03/2006; 34(2):296-304. · 3.74 Impact Factor