Micronucleus induction and chromosome loss in transformed human white cells indicate clastogenic and aneugenic action of the cyanobacterial toxin, cylindrospermopsin

• Published in: Mutation research Vol. 472; no. 1; pp. 155 - 161
• Main Authors: Humpage, Andrew R, Fenech, Michael, Thomas, Philip, Falconer, Ian R
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 20.12.2000; Elsevier
• Subjects: Bacterial Toxins; Bacteriology; Biological and medical sciences; Carcinogenesis; Cell Line, Transformed; Centromere - drug effects; Cyanobacteria; Cyanophyta; Cylindrospermopsis; Cylindrospermopsis raciborskii; DNA Primers; Fundamental and applied biological sciences. Psychology; Humans; Loss of Heterozygosity; Lymphoblastoid cell-line; Lymphocytes; Medical sciences; Microbiology; Micronuclei, Chromosome-Defective - drug effects; Micronucleus Tests; Miscellaneous; Mutagenicity Tests; Mutagens - toxicity; Oligonucleotide Probes; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Polymerase Chain Reaction; Toxicology; Uracil - analogs & derivatives; Uracil - toxicity; Cylindrospermopsis; CYT-B, cytochalasin-B; CEN/s, centromere/s; SSC, saline-sodium citrate buffer; MMC, mitomycin-C; CBMN, cytokinesis-block micronucleus assay; CYN, cylindrospermopsin; Carcinogenesis; MN/i, micronucleus/micronuclei; FCS, foetal calf serum; NDI, nuclear division index; FISH, fluorescence in situ hybridisation; MNBNC/s, micronucleated binucleated cell/s; BNC/s, binucleated cell/s; Lymphoblastoid cell-line; Chromosomal aberration; Human; Toxin; Cell line; Micronucleus test; Protein synthesis; Mutagenicity testing; Toxicity; Cyanobacteria; Bacteria; Inhibitor; Lymphoblastoid cell
• ISSN: 1383-5718; 0027-5107; 1879-3592
• DOI: 10.1016/S1383-5718(00)00144-3

Cylindrospermopsin (CYN) is a potent inhibitor of protein synthesis produced by a number of cyanobacterial species, the most common being Cylindrospermopsis raciborskii. CYN contains a uracil moiety attached to a sulphated guanidino moiety, suggesting that it may have carcinogenic activity. This report describes the use of the WIL2-NS lymphoblastoid cell-line in the well-validated cytokinesis-block micronucleus (CBMN) assay to test this hypothesis. Centromeres (CENs) were identified in micronuclei (MNi) of binucleated cells (BNCs) by fluorescent in situ hybridisation of alpha centromeric DNA sequence repeats. The results indicate that CYN induced a significant increase in the frequency of MNi in BNCs exposed to 6 and 10 μg/ml, and a significant increase in CEN-positive MNi at all concentrations of CYN tested (1, 3, 6, and 10 μg/ml). However, despite this apparently greater sensitivity of WIL2-NS cells to induction of CEN-positive MNi at low CYN concentrations, at the higher concentrations the magnitude of the increase in CEN-positive MNi did not account for the greater increase in MNi in BNCs, indicating that both CEN-positive and CEN-negative MNi were induced. This suggests that CYN acts to induce cytogenetic damage via two mechanisms, one at the level of the DNA to induce strand breaks, the other at the level of kinetochore/spindle function to induce loss of whole chromosomes (aneuploidy). C. raciborskii occurs in a number of human drinking water sources worldwide and so these findings may have important public health implications.