Inhibition of N-acetyltransferase activity and gene expression in human colon cancer cell lines by diallyl sulfide
ABSTRACT Diallyl sulfide (DAS) is one of the major components of garlic (Allium sativum) and is widely used in the world for food. In this study, DAS was selected for testing the inhibition of arylamine N-acetyltransferase (NAT) activity (N-acetylation of 2-aminofluorene) and gene expression (mRNA NAT) in human colon cancer cell lines (colo 205, colo 320 DM and colo 320 HSR). The NAT activity was examined by high performance liquid chromatography and indicated that a 24 h DAS treatment decreases N-acetylation of 2-aminofluorene in three colon (colo 205, 320 DM and colo 320 HSR) cancer cell lines. The NAT enzymes (protein) were analyzed by western blotting and flow cytometry and it indicated that DAS decreased the levels of NAT in three colon (colo 205, 320 DM and colo 320 HSR) cancer cell lines. The gene expression of NAT (mRNAT NAT) was determined by polymerase chain reaction (PCR), it was shown that DAS affect mRNA NAT expression in examined human colon cancer cell lines. This report is the first to demonstrate that DAS does inhibit human colon cancer cell NAT activity and gene expression.
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ABSTRACT: Garlic has been reported to have chemopreventive effects against a variety of cancers. However, different garlic preparations contain different constituents. We investigated the chemopreventive effect of aged garlic extract (AGE), an odorless product from prolonged extraction of fresh garlic, on colon carcinogenesis and cell proliferation in 1,2- dimethylhydrazine (DMH)-induced colon neoplastic rats. Rats were given weekly subcutaneous injections of DMH (20mg/kg) for 20 wk, and fed either a basal diet or one containing 4% AGE. Serum from AGE-treated rats contained detectable S-allylcysteine. The AGE diet significantly reduced the number of colon tumors and aberrant crypt foci compared to the basal diet. Cell proliferation of normal-appearing colonic mucosa was assessed by MIB-5 immunohistochemistry. AGE treatment significantly decreased the mean MIB-5-labeling index. These findings suggest AGE has a chemopreventive effect on colon carcinogenesis through suppression of cell proliferation. J. Nutr. 136: 847S-851S, 2006.
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ABSTRACT: Previous studies have demonstrated that berberine decreases N-acetyltransferase (NAT) activity in human leukemia HL-60 cells, however, NAT gene expression has not been investigated. In this study, berberine was selected for testing the inhibition of N-acetylation of 2-aminofluorene (AF) and NAT gene expression in human HL-60 cells. The N-acetylation of AF was determined and quantitated by high performance liquid chromatography (HPLC). The data showed that a 24-hour berberine treatment decreased the amount of N-acetylation of AF in HL-60 cells. The NAT enzymes were stained and examined by Western blotting and flow cytometry. The results indicated that berberine decreased the levels of NAT protein in HL-60 cells. The expression of NAT gene (mRNAT NAT1) was determined by polymerase chain reaction (PCR), and it was found that berberine had inhibited the expression of mRNA NAT1 in human HL-60 cells.Anticancer research 01/2005; 25(6B):4149-55. · 1.87 Impact Factor
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ABSTRACT: It is well documented that arylamine carcinogens are N-acetylated by cytosolic N-acetyltransferase (NAT) enzyme. NAT plays an important role in the metabolizing of those arylamine compounds. 2-Aminofluorene (AF) is an arylamine carcinogen which has been demonstrated to induce carcinogenesis in laboratory animals. Our previous study has shown that a human promyelocytic leukemia cell line, HL-60, displays NAT activity. The purpose of the present study was to determine whether or not wogonin could affect the N-acetylation of AF in HL-60. N-acetylated and non-N-acetylated AF were determined by using high performance liquid chromatography. Wogonin displayed a dose-dependent inhibition of NAT activity in cytosols and intact cells. Wogonin also decreased AF-DNA adduct formation in these cells. The effects of wogonin on the NAT enzymes levels were also examined by Western blotting and flow cytometry and the changes of NAT gene expression were examined by polymerase chain reaction (PCR) and cDNA microarray. The results demonstrated that wogonin inhibited NAT1 mRNA gene expression and the level of NAT enzyme in HL-60 cells. This is the first demonstration that wogonin affects human leukemia cells' NAT activity in vitro.Anticancer research 01/2005; 25(1A):127-32. · 1.87 Impact Factor