Gypenosides inhibited N-acetylation of 2-aminofluorene, N-acetyltransferase gene expression and DNA adduct formation in human cervix epithelioid carcinoma cells (HeLa).
N-acetylation plays an important role in the metabolism of arylamine drugs and carcinogens and is catalyzed by cytosolic N-acetyltransferase (NAT). Gypenosides are the major components of Gynostemma pentaphyllum Makino which had been used as a natural folk medicine in the Chinese populations. Gypenosides were selected for examining the inhibition on the N-acetylation of 2-aminofluorene (AF), DNA-AF adduct formation and NAT gene expression in the human cervix epithelioid carcinoma cell line (HeLa). Various concentrations of gypenosides were individually added to the culture medium of human cervix epithelioid carcinoma cells (HeLa). The N-acetylation of AF was determined by high performance liquid chromatography (HPLC) assaying for the amounts of acetylated 2-aminofluorene (AAF) and nonacetylated 2-aminofluorene (AF). The N-acetylation of AF in the human HeLa cancer cells was suppressed by gypenosides in a dose-dependent manner. The data also demonstrated that gene expression (NAT1 mRNA) of NAT in human cervix epithelioid carcinoma cells (HeLa) was inhibited and decreased by gypenosides. After the incubation of HeLa cells with 30 or 60 microM AF and with or without 350 microg/ml gypenosides cotreatment, DNA was isolated and hydrolyzed to nucleotides, adducted nucleotides were extracted into butanol and analyzed DNA-AF adducts by HPLC. The data demonstrated that gypenosides decrease the levels of DNA-AF adduct formation in HeLa cells.
Chiu
Tsan-Hung
TH
Department of Obstetrics and Gynecology, China Medical University Hospital, 2 Yuh-Der Road, Taichung 404, Taiwan, ROC.
Chen
Jung-Chou
JC
Chen
Lieh-Der
LD
Lee
Jau-Hong
JH
Chung
Jing-Gung
JG
D000107:Acetylation / Q000187:drug effects; D001191:Arylamine N-Acetyltransferase / Q000235:genetics / Q000378:metabolism*; D002273:Carcinogens / Q000032:analysis / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media / Q000494:pharmacology; D018736:DNA Adducts / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D005449:Fluorenes / Q000032:analysis / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects*; D029774:Gynostemma / Q000633:toxicity; D006367:HeLa Cells; D006801:Humans; D010936:Plant Extracts / Q000633:toxicity*; D012333:RNA, Messenger / Q000378:metabolism
D002273:Carcinogens; D003470:Culture Media; D018736:DNA Adducts; D005449:Fluorenes; D010936:Plant Extracts; D012333:RNA, Messenger; C474918:gypenoside; C012177:2-aminofluorene; D001191:Arylamine N-Acetyltransferase