ABSTRACT
Retinoids are key modulators of the cellular functions in many tissues including the skin. All-fraAis-retinoic acid, a metabolite of vitamin A, and synthetic retinoids has long been used for the treatment of skin diseases, including acne and psoriasis. Natural and synthetic retinoids can inhibit the differentiation of cultured keratinocytes. HaCaT, a spontaneously transformed human keratinocyte cell line, was used to study the apoptotic potential of several retinoids. Apoptosis-inducing properties of retinoids can be assayed in vitro using the transformed human keratinocyte cell line HaCaT. Apoptosis can be followed in individual cells by enzymatic in situ labeling with exogenous terminal deoxynucleotidyltransferase. The chapter presents the models to determine the affinity of retinoids for the different RAR subtypes and RXRα, to measure the differentiation of keratinocytes and the modulating effect of retinoids, and to study the apoptosis induction potential of the compounds.
