Inhibition of cellular efflux pumps involved in multi xenobiotic resistance (MXR) in echinoid larvae as a possible mode of action for increased ecotoxicological risk of mixtures

H.M.R. Drs Anselmo, J.H.J. van den Berg, I. Rietjens, A.J. Murk

Research output: Contribution to journalArticleAcademicpeer-review

31 Citations (Scopus)

Abstract

In marine organisms the multi xenobiotic resistance (MXR) mechanism via e.g. P-glycoprotein (P-gp) and multidrug resistance-associated protein (MRP) is an important first line of defense against contaminants by pumping contaminants out of the cells. If compounds would impair the MXR mechanism, this could result in increased intracellular levels of other compounds, thereby potentiating their toxicity. A calcein-AM based larval cellular efflux pump inhibition assay (CEPIA) was developed for echinoid (Psammechinus miliaris) larvae and applied for several contaminants. The larval CEPIA revealed that triclosan (TCS) and the nanoparticles P-85® (P-85) were 124 and 155× more potent inhibitors (IC50 0.5 ± 0.05 and 0.4 ± 0.1 µM, respectively) of efflux pumps than the model inhibitor Verapamil (VER). PFOS (heptadecafluorooctane sulfonic acid) and pentachlorophenol also were more potent than VER, 24 and 5×, respectively. Bisphenol A and o,p'-dichlorodiphenyltrichloroethane (o,p'-DDT) inhibited efflux pumps with a potency 3× greater than VER. In a 48 h early life stage bioassay with P. miliaris, exposure to a non-lethal concentration of the inhibitors TCS, VER, the model MRP inhibitor MK-571, the nanoparticles P-85 and the model P-gp inhibitor PSC-833, increased the toxicity of the toxic model substrate for efflux pumps vinblastine by a factor of 2, 4, 4, 8 and 16, respectively. Our findings show that several contaminants accumulating in the marine environment inhibit cellular efflux pumps, which could potentiate toxic effects of efflux pumps substrates
Original languageEnglish
Pages (from-to)2276-2287
JournalEcotoxicology
Volume21
Issue number8
DOIs
Publication statusPublished - 2012

Keywords

  • multixenobiotic defense-mechanism
  • mussel mytilus-galloprovincialis
  • urchin psammechinus-miliaris
  • p-glycoprotein
  • aquatic organisms
  • pluronic p85
  • drug efflux
  • marine mussel
  • bivalve gills
  • in-vitro

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