title: Chemopreventive mechanisms of methionine on inhibition of benzo(a)pyrene-DNA adducts formation in human hepatocellular carcinoma HepG2 cells.
abstract: This study was designed to investigate the molecular mechanism underlying the chemopreventive effects of methionine on benzo[a]pyrene (B[a]P)-DNA adducts formation in HepG2 cells. Methionine significantly inhibited B[a]P-DNA adduct formation in HepG2 cells. Methionine significantly decreased the cellular uptake of [(3)H] B[a]P, but increased the cellular discharge of [(3)H] B[a]P from HepG2 cells into the media. B[a]P significantly lowered total cellular glutathione (GSH) level, but co-cultured with B[a]P and methionine, gradually attenuated intracellular GSH levels in a concentration-dependent manner, which was markedly higher at 20-500μM methionine. The cellular proteins of treated cells were resolved by 2D-polyacrylamide gel electrophoresis. Proteomic profiles showed that phase II enzymes such as glutathione S-transferase (GST) omega-1, GSTM3, glyoxalase I (GLO1) and superoxide dismutase (SOD) were down-regulated by B[a]P treatment, whereas cathepsin B (CTSB), Rho GDP-dissociation inhibitor alpha (Rho-GDP-DIA), histamine N-methyltransferase (HNMT), spermidine synthase (SRM) and arginase-1 (ARG1) were up-regulated by B[a]P. B[a]P and methionine treatments, GST omega-1, GSTM3, GLO1 and SOD were significantly enhanced compared to B[a]P alone. Similarly, methionine was effective in diminishing the B[a]P-induced up-regulation of CTSB, Rho-GDP-DIA, HNMT, SRM and ARG1. Our data suggests that methionine might exert a chemoprotective effect on B[a]P-DNA adduct formation by attenuating intracellular GSH levels, blocking the uptake of B[a]P into cells, or by altering expression of proteins involved in DNA adduct formation.
authors.affiliation: Division of Toxicology, School of Pharmacy, Sungkyunkwan University, Suwon, Gyeonggi-do, 440-746, Republic of Korea.
authors.forename: Taehyun
authors.initials: T
authors.lastname: Roh
authors.forename: Min Young
authors.initials: MY
authors.lastname: Kwak
authors.forename: Eun Hwa
authors.initials: EH
authors.lastname: Kwak
authors.forename: Dong Hyun
authors.initials: DH
authors.lastname: Kim
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Han
authors.forename: Jung Yun
authors.initials: JY
authors.lastname: Bae
authors.forename: Du Yeon
authors.initials: du Y
authors.lastname: Bang
authors.forename: Duck Soo
authors.initials: DS
authors.lastname: Lim
authors.forename: Il Young
authors.initials: IY
authors.lastname: Ahn
authors.forename: Dong Eun
authors.initials: DE
authors.lastname: Jang
authors.forename: Seong Kwang
authors.initials: SK
authors.lastname: Lim
authors.forename: Sun Dong
authors.initials: SD
authors.lastname: Yoo
authors.forename: Seung Jun
authors.initials: SJ
authors.lastname: Kwack
authors.forename: Kiu Lea
authors.initials: KL
authors.lastname: Park
authors.forename: Young Ju
authors.initials: YJ
authors.lastname: Lee
authors.forename: Kyu-Bong
authors.initials: KB
authors.lastname: Kim
authors.forename: Jaewon
authors.initials: J
authors.lastname: Lee
authors.forename: Hyung Sik
authors.initials: HS
authors.lastname: Kim
authors.forename: Byung Mu
authors.initials: BM
authors.lastname: Lee
mesh_terms: D001119:Arginase / Q000032:analysis; D001564:Benzo(a)pyrene / Q000037:antagonists & inhibitors*; D002401:Cathepsin B / Q000032:analysis; D018736:DNA Adducts / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D005982:Glutathione Transferase / Q000032:analysis; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000032:analysis; D056945:Hep G2 Cells; D006637:Histamine N-Methyltransferase / Q000032:analysis; D006801:Humans; D007791:Lactoylglutathione Lyase / Q000032:analysis; D008113:Liver Neoplasms / Q000139:chemically induced* / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D008715:Methionine / Q000494:pharmacology*; D040901:Proteomics / Q000379:methods*; D011436:Spermidine Synthase / Q000032:analysis; D013482:Superoxide Dismutase / Q000032:analysis; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors
chemical_list: D018736:DNA Adducts; D020730:Guanine Nucleotide Dissociation Inhibitors; C056612:benzo(a)pyrene-DNA adduct; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D001564:Benzo(a)pyrene; D008715:Methionine; D013482:Superoxide Dismutase; D006637:Histamine N-Methyltransferase; D011436:Spermidine Synthase; C483009:GSTM3 protein, human; C490476:GSTO1 protein, human; D005982:Glutathione Transferase; C533912:CTSB protein, human; D002401:Cathepsin B; D001119:Arginase; D007791:Lactoylglutathione Lyase