Evaluation of Electrochemiluminescent Metabolic Toxicity Screening Arrays Using a Multiple Compound Set

摘要

ABSTRACT: Arrays for screening metabolite-generated toxicity utiliz-ning spots containing DNA, enzyme, and electroluminescent (ECL)npolymer ([Ru(bpy)2PVP10]n2þ) were extended to include a fully repre-nsentative set ofmetabolic enzymes fromhuman and rat livermicrosomes,nhuman and rat liver cytosol, and mouse liver S9 fractions. Array useninvolves two steps: (1) enzyme activation of the test chemical andnmetabolite reaction with DNA, and then, (2) capture of ECL resultingnfrom DNA damage using a charge coupled device (CCD) camera. Plotsnof ECL increase vs enzyme reaction time monitor relative rates of DNAndamage and were converted into turnover rates for enzymic productionnof DNA-reactive metabolites. ECL turnover rates were defined by R, the initial slope of ECL increase versus enzyme reaction timennormalized for amounts of enzyme and test chemical. R-values were used to establish correlations for 11 toxic compounds with thenstandard toxicity metrics rodent liver TD50 and lethal dose (LD50), Ames tests, and Comet assays for in vitro DNA damage. Resultsnsupport the value of the ECL genotoxicity arrays together with toxicity bioassays for early screening of new chemicals and drugncandidates.