title: Collaborative study for the detection of toxic compounds in shellfish extracts using cell-based assays. Part I: screening strategy and pre-validation study with lipophilic marine toxins.
abstract: Human poisoning due to consumption of seafood contaminated with phycotoxins is a worldwide problem, and routine monitoring programs have been implemented in various countries to protect human consumers. Following successive episodes of unexplained shellfish toxicity since 2005 in the Arcachon Bay on the French Atlantic coast, a national research program was set up to investigate these atypical toxic events. Part of this program was devoted to fit-for-purpose cell-based assays (CBA) as complementary tools to collect toxicity data on atypical positive-mouse bioassay shellfish extracts. A collaborative study involving five laboratories was conducted. The responses of human hepatic (HepG2), human intestinal (Caco2), and mouse neuronal (Neuro2a) cell lines exposed to three known lipophilic phycotoxins-okadaic acid (OA), azaspiracid-1 (AZA1), and pectenotoxin-2 (PTX2)-were investigated. A screening strategy composed of standard operating procedures and a decision tree for dose-response modeling and assay validation were designed after a round of "trial-and-error" process. For each toxin, the shape of the concentration-response curves and the IC(50) values were determined on the three cell lines. Whereas OA induced a similar response irrespective of the cell line (complete sigmoid), PTX2 was shown to be less toxic. AZA1 induced cytotoxicity only on HepG2 and Neuro2a, but not on Caco2. Intra- and inter-laboratory coefficients of variation of cell responses were large, with mean values ranging from 35 to 54 % and from 37 to 48 %, respectively. Investigating the responses of the selected cell lines to well-known toxins is the first step supporting the use of CBA among the panel of methods for characterizing atypical shellfish toxicity. Considering these successful results, the CBA strategy will be further applied to extracts of negative, spiked, and naturally contaminated shellfish tissues.
authors.affiliation: Unité de Toxicologie des Contaminants, ANSES, 35302 Fougères, France.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Sérandour
authors.forename: Aurélie
authors.initials: A
authors.lastname: Ledreux
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Morin
authors.forename: Sylvain
authors.initials: S
authors.lastname: Derick
authors.forename: Elie
authors.initials: E
authors.lastname: Augier
authors.forename: Rachelle
authors.initials: R
authors.lastname: Lanceleur
authors.forename: Sahima
authors.initials: S
authors.lastname: Hamlaoui
authors.forename: Serge
authors.initials: S
authors.lastname: Moukha
authors.forename: Christophe
authors.initials: C
authors.lastname: Furger
authors.forename: Ronel
authors.initials: R
authors.lastname: Biré
authors.forename: Sophie
authors.initials: S
authors.lastname: Krys
authors.forename: Valérie
authors.initials: V
authors.lastname: Fessard
authors.forename: Marc
authors.initials: M
authors.lastname: Troussellier
authors.forename: Cécile
authors.initials: C
authors.lastname: Bernard
mesh_terms: D000818:Animals; D002460:Cell Line; D003299:Cooperative Behavior; D004305:Dose-Response Relationship, Drug; D006801:Humans; D020128:Inhibitory Concentration 50; D008387:Marine Toxins / Q000032:analysis* / Q000633:toxicity; D012758:Shellfish
chemical_list: D008387:Marine Toxins