title: Fusaric Acid Induces DNA Damage and Post-Translational Modifications of p53 in Human Hepatocellular Carcinoma (HepG2) Cells.
abstract: Fusaric acid (FA), a common fungal contaminant of maize, is known to mediate toxicity in plants and animals; however, its mechanism of action is unclear. p53 is a tumor suppressor protein that is activated in response to cellular stress. The function of p53 is regulated by post-translational modifications-ubiquitination, phosphorylation, and acetylation. This study investigated a possible mechanism of FA induced toxicity in the human hepatocellular carcinoma (HepG2) cell line. The effect of FA on DNA integrity and post-translational modifications of p53 were investigated. Methods included: (a) culture and treatment of HepG2cells with FA (IC50: 580.32 μM, 24 h); (b) comet assay (DNA damage); (c) Western blots (protein expression of p53, MDM2, p-Ser-15-p53, a-K382-p53, a-CBP (K1535)/p300 (K1499), HDAC1 and p-Ser-47-Sirt1); and (d) Hoechst 33342 assay (apoptosis analysis). FA caused DNA damage in HepG2cells relative to the control (P < 0.0001). FA decreased the protein expression of p53 (0.24-fold, P = 0.0004) and increased the expression of p-Ser-15-p53 (12.74-fold, P = 0.0126) and a-K382-p53 (2.24-fold, P = 0.0096). This occurred despite the significant decrease in the histone acetyltransferase, a-CBP (K1535)/p300 (K1499) (0.42-fold, P = 0.0023) and increase in the histone deacetylase, p-Ser-47-Sirt1 (1.22-fold, P = 0.0020). The expression of MDM2, a negative regulator of p53, was elevated in the FA treatment compared to the control (1.83-fold, P < 0.0001). FA also inhibited cell proliferation and induced apoptosis in HepG2cells as evidenced by the Hoechst assay. Together, these results indicate that FA is genotoxic and post-translationally modified p53 leading to HepG2cell death. J. Cell. Biochem. 118: 3866-3874, 2017. © 2017 Wiley Periodicals, Inc.
authors.affiliation: Discipline of Medical Biochemistry and Chemical Pathology, School of Laboratory Medicine and Medical Science, College of Health Sciences, University of Kwa-Zulu Natal, Congella, Durban, 4013, South Africa.
authors.forename: Terisha
authors.initials: T
authors.lastname: Ghazi
authors.affiliation: Discipline of Medical Biochemistry and Chemical Pathology, School of Laboratory Medicine and Medical Science, College of Health Sciences, University of Kwa-Zulu Natal, Congella, Durban, 4013, South Africa.
authors.forename: Savania
authors.initials: S
authors.lastname: Nagiah
authors.affiliation: Discipline of Medical Biochemistry and Chemical Pathology, School of Laboratory Medicine and Medical Science, College of Health Sciences, University of Kwa-Zulu Natal, Congella, Durban, 4013, South Africa.
authors.forename: Charlette
authors.initials: C
authors.lastname: Tiloke
authors.affiliation: Discipline of Medical Biochemistry and Chemical Pathology, School of Laboratory Medicine and Medical Science, College of Health Sciences, University of Kwa-Zulu Natal, Congella, Durban, 4013, South Africa.
authors.forename: Naeem
authors.initials: N
authors.lastname: Sheik Abdul
authors.affiliation: Discipline of Medical Biochemistry and Chemical Pathology, School of Laboratory Medicine and Medical Science, College of Health Sciences, University of Kwa-Zulu Natal, Congella, Durban, 4013, South Africa.
authors.forename: Anil A
authors.identifier: 0000-0003-4649-4133
authors.initials: AA
authors.lastname: Chuturgoon
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D006528:Carcinoma, Hepatocellular / Q000378:metabolism* / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects; D004249:DNA Damage; D005669:Fusaric Acid / Q000494:pharmacology*; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D005669:Fusaric Acid
keywords: DNA DAMAGE; FUSARIC ACID; POST-TRANSLATIONAL MODIFICATIONS; a-K382-p53; p-Ser-15-p53; p53