title: Induction of DNA damage signaling genes in benzidine-treated HepG2 cells.
abstract: We examined genotoxicity and DNA damage response in HepG2 cells following exposure to benzidine. Using the Comet assay, we showed that benzidine (50-200 μM) induces DNA damage in HepG2 cells. DNA damage signaling pathway-based PCR arrays were used to investigate expression changes in genes involved in cell-cycle arrest, apoptosis, and DNA repair and showed upregulation of 23 genes and downregulation of one gene in benzidine-treated cells. Induction of G2/M arrest and apoptosis was confirmed at the protein level. Real-time PCR and Western blots were used to demonstrate the expression of select DNA repair-associated genes from the PCR array. Upregulation of the p53 protein in benzidine-treated cells suggests the induction of the p53 DNA damage signaling pathway. Collectively, DNA damage response genes induced by benzidine indicate recruitment complex molecular machinery involved in DNA repair, cell-cycle arrest, and potentially, activation of the apoptosis.
authors.affiliation: Department of Life Science, National Central University, Chung-Li City, Taoyan Country, Taiwan, Republic of China. osycchna@ksts.seed.net.tw
authors.forename: Ssu
authors.initials: S
authors.lastname: Ching Chen
authors.forename: You-Cheng
authors.initials: YC
authors.lastname: Hseu
authors.forename: Jia-Chuen
authors.initials: JC
authors.lastname: Sung
authors.forename: Chin-Hui
authors.initials: CH
authors.lastname: Chen
authors.forename: Lei-Chin
authors.initials: LC
authors.lastname: Chen
authors.forename: King-Tom
authors.initials: KT
authors.lastname: Chung
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D001560:Benzidines / Q000633:toxicity*; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D020552:Comet Assay; D004249:DNA Damage / Q000235:genetics*; D004260:DNA Repair / Q000235:genetics*; D015536:Down-Regulation; D020869:Gene Expression Profiling; D056945:Hep G2 Cells; D006801:Humans; D009153:Mutagens / Q000633:toxicity*; D060888:Real-Time Polymerase Chain Reaction; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*; D015854:Up-Regulation
chemical_list: D001560:Benzidines; D009153:Mutagens; D016159:Tumor Suppressor Protein p53; C029876:benzidine