Characterization of retinoic acid receptor-deficient keratinocytes.
Retinoids are essential for normal epidermal growth and differentiation and show potential for the prevention or treatment of various epithelial neoplasms. The retinoic acid receptors (RARalpha, -beta, and -gamma) are transducers of the retinoid signal. The epidermis expresses RARgamma and RARalpha, both of which are potential mediators of the effects of retinoids in the epidermis. To further investigate the role(s) of these receptors, we derived transformed keratinocyte lines from wild-type, RARalpha, RARgamma, and RARalphagamma null mice and investigated their response to retinoids, including growth inhibition, markers of growth and differentiation, and AP-1 activity. Our results indicate that RARgamma is the principle receptor contributing to all-trans-retinoic acid (RA)-mediated growth arrest in this system. This effect partially correlated with inhibition of AP-1 activity. In the absence of RARs, the synthetic retinoid N-(4-hydroxyphenyl)-retinamide inhibited growth; this was not observed with RA, 9-cis RA, or the synthetic retinoid (E)-4-[2-(5, 5, 8, 8 tetramethyl-5,6,7,8-tetrahydro-2-naphthalenyl)-1-propenyl] benzoic acid. Finally, both RARalpha and RARgamma differently affected the expression of some genes, suggesting both specific and overlapping roles for the RARs in keratinocytes.
Goyette
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Department of Molecular Biology, Université de Montréal, Division of Experimental Medicine, McGill University, and the Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins, Ouest, Montréal, Québec H2W 1R7, Canada.
Feng Chen
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C
Wang
W
W
Seguin
F
F
Lohnes
D
D
D000818:Animals; D001483:Base Sequence; D002455:Cell Division; D017931:DNA Primers; D005786:Gene Expression Regulation / Q000235:genetics; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D018168:Receptors, Retinoic Acid / Q000235:genetics / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000378:metabolism
D017931:DNA Primers; D018168:Receptors, Retinoic Acid; D018808:Transcription Factor AP-1