title: Dynamic cytotoxic response to microcystins using microelectronic sensor arrays.
abstract: Microcystins are bioactive metabolites produced by cyanobacteria in water. These cyclic heptapeptides have caused public health concern worldwide. By interfering with cellular phosphorylation and signaling, microcystins can cause acute and chronic liver diseases. Therefore, the World Health Organization (WHO) has set the provisional drinking water guideline value at 1.0 microg/L for microcystin-LR (free plus cell-bound). Microcystins do not readily cross cell membranes in in vitro cell-based assays, except for those using freshly isolated hepatocytes. However, the sensitivity of in vitro cell-based assays is not adequate for testing samples at low environmental concentrations. Hence, there is a need to develop a sensitive and stable cytotoxicity assay for use in environmental studies. On the basis of the observation that microcystin-LR can be transported by the liver-specific members of the organic anion transporting polypeptides (OATPs), we investigated the potential of using an OATP1B3-expressing cell line in a cytotoxicity assay for microcystins. Using a novel cell electronic sensing system (RT-CES), we were able to monitor the real-time, dynamic cytotoxic response to microcystins at microgram per liter concentrations. We demonstrated that the cytotoxicity of the most common microcystins, -LR, -YR, -RR, -LF, and -LW, was mediated by OATP1B3 transporters. Microcystin-LF is the most potent toxin among the five congeners. In conclusion, we have established a highly automated, real-time, sensitive, and stable assay for measuring microcystin cytoxicity.
authors.affiliation: Alberta Centre for Toxicology, Department of Physiology and Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada. yhuang@ucalgary.ca
authors.forename: Dorothy Yu
authors.initials: DY
authors.lastname: Huang
authors.forename: Melissa
authors.initials: M
authors.lastname: Mock
authors.forename: Bruno
authors.initials: B
authors.lastname: Hagenbuch
authors.forename: Siu
authors.initials: S
authors.lastname: Chan
authors.forename: Jasna
authors.initials: J
authors.lastname: Dmitrovic
authors.forename: Stephan
authors.initials: S
authors.lastname: Gabos
authors.forename: David
authors.initials: D
authors.lastname: Kinniburgh
mesh_terms: D000818:Animals; D016466:CHO Cells; D002462:Cell Membrane / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D006801:Humans; D051379:Mice; D052998:Microcystins / Q000378:metabolism / Q000633:toxicity*; D008839:Microelectrodes; D029362:Organic Anion Transporters, Sodium-Independent / Q000378:metabolism*; D000074542:Solute Carrier Organic Anion Transporter Family Member 1B3; D013778:Tetrazolium Salts; D013844:Thiazoles; D018675:Toxicity Tests / Q000379:methods*
chemical_list: D052998:Microcystins; D029362:Organic Anion Transporters, Sodium-Independent; C421209:SLCO1B3 protein, human; D000074542:Solute Carrier Organic Anion Transporter Family Member 1B3; D013778:Tetrazolium Salts; D013844:Thiazoles; C022616:thiazolyl blue