Genotoxic effects of the cyanobacterial hepatotoxin cylindrospermopsin in the HepG2 cell line

• Published in: Archives of toxicology Vol. 85; no. 12; pp. 1617 - 1626
• Main Authors: STRASER, Alja, FILIPIC, Metka, ZEGURA, Bojana
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.12.2011; Springer; Springer Nature B.V
• Subjects: Antimicrobial agents; Bacterial Toxins; Bacteriology; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; DNA Breaks - drug effects; DNA damage; DNA Damage - drug effects; Dose-Response Relationship, Drug; Environmental Health; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation - drug effects; Genotoxicity and Carcinogenicity; Health risk assessment; Hep G2 Cells; Humans; Liver; Medical sciences; Microbiology; Mutagenicity Tests; Mutagens - administration & dosage; Mutagens - toxicity; Occupational Medicine/Industrial Medicine; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Pharmacology/Toxicology; Polymerase Chain Reaction; Time Factors; Toxicity; Toxicology; Uracil - administration & dosage; Uracil - analogs & derivatives; Uracil - toxicity; Nuclear bud; Nucleoplasmic bridge; Gene expression; DNA damage; Cylindrospermopsin; Micronucleus; Human; Digestive system; Toxicity; Liver; Genotoxicity; In vitro; Bud; Toxin; Chromosome break; Cell line; Hepatocyte; DNA; Cyanobacteria; Established cell line; Bacteria; Lesion; Genotoxity test
• ISSN: 0340-5761; 1432-0738
• DOI: 10.1007/s00204-011-0716-z

The cyanobacterial alkaloid cylindrospermopsin (CYN) is being increasingly identified in drinking water supplies worldwide. It is a potent protein synthesis inhibitor and causes human intoxications and animal mortality. The few genotoxicity studies available indicate that CYN is genotoxic, generally implying that it is pro-genotoxic. We evaluated CYN genotoxicity in the human hepatoma cell line, HepG2, analyzing the induction of DNA strand breaks, with the alkaline comet assay, and micronuclei (MNi), nuclear bud (NBUD), and nucleoplasmic bridge (NPB) formation, with the cytokinesis block micronucleus (CBMN) assay. In addition, changes in the expression of genes involved in the response to DNA damage ( P53 , CDKN1A , GADD45α , and MDM2 ) and genes presumably involved in CYN metabolism (genes from the Cytochrome P450 family: CYP1A1 and CYP1A2 ) were determined, using quantitative real-time PCR. Non-cytotoxic concentrations of CYN induced increased DNA damage after 12 and 24 h of exposure and increased the frequency of MNi, NBUDs, and NPBs after 24 h exposure. Moreover, CYN up-regulated the expression of the CYP1A1 and CYP1A2 genes. Although no changes in the expression of the P53 tumor-suppressor gene were found, CYN up-regulated the expression of the P53 downstream-regulated genes CDKN1A , GADD45α , and MDM2 . Our results provide new evidence that CYN is genotoxic and strongly suggest that it needs to be considered in the human health risk assessment.