Restricted accessResearch articleFirst published online 2010-06
Evaluation of a Range of Anti-Proliferative Assays for the Preclinical Screening of Anti-Psoriatic Drugs: A Comparison of Colorimetric and Fluorimetric Assays with the Thymidine Incorporation Assay
Established treatments for psoriasis are generally based on anti-proliferative, anti-inflammatory, or differentiation-modifying activity, or a combination of these effects. New agents for the treatment of psoriasis could be identified by high-throughput screening (HTS) of large compound libraries using keratinocyte proliferation models. Although several new proliferation assays have been developed, the radioactive [3H]-thymidine incorporation assay is still considered to be the gold standard for the evaluation of keratinocyte proliferation in vitro. In this study, we compare a number of simple, and reliable, colorimetric (MTT, NRU, SRB, and CVS), and fluorimetric (CAM and AB) methods with the [3H]-thymidine incorporation assay for the measurement of keratinocyte proliferation in the exponential growth phase in 96-well formats. The concentrations that induced 50% growth inhibition (GI50) were determined by each assay for the established antipsoriatics, dithranol, and methotrexate. Strong correlations were observed between the percentage growth inhibitions determined by the radioactive and the colorimetric assays, with no significant differences (P > 0.05) between their GI50 values. The colorimetric assays are thus suitable alternatives to the radioactive assay for quantifying keratinocyte growth inhibition. We have also validated the use of the HaCaT cell line as a representative of the hyper-proliferative psoriatic epidermis, in the preclinical screening of experimental anti-psoriatic agents.
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