Archives of Toxicology

, Volume 85, Issue 12, pp 1617–1626

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

Genotoxicity and Carcinogenicity

DOI: 10.1007/s00204-011-0716-z

Cite this article as:
Štraser, A., Filipič, M. & Žegura, B. Arch Toxicol (2011) 85: 1617. doi:10.1007/s00204-011-0716-z

Abstract

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.

Keywords

Cylindrospermopsin DNA damage Micronucleus Nuclear bud Nucleoplasmic bridge Gene expression 

Abbreviations

BaP

Benzo[a]pyrene

BNC

Binucleated cells

CYN

Cylindrospermopsin

CYP450

Cytochrome p-450

CBMN

Cytokinesis block micronucleus assay

MNed

Micronucleated

MNi

Micronuclei

MTT

3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide

NDI

Nuclear division index

NBUD

Nuclear bud

NPB

Nucleoplasmic bridge

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  1. 1.Department for Genetic Toxicology and Cancer BiologyNational Institute of BiologyLjubljanaSlovenia

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