Abstract
Induction of apoptosis in lymphocytes, which may account for the therapeutic effects of glucocorticoids in various diseases including leukemia, depends on the glucocorticoid receptor. However, the events leading from the activated receptor to cell lysis are not understood. A prevailing hypothesis postulates induction of so-called 'lysis genes' by the activated receptor. In this study, we show that an activation-deficient glucocorticoid receptor mutant is as effective as the wild-type receptor in repression of AP-1 activity, inhibition of interleukin-2 production, inhibition of c-myc expression and induction of apoptosis. Furthermore, we show that retinoic acid can also induce apoptosis in these cells through the retinoic acid receptor, whose repressive functions but not target site specificity, are similar to those of the glucocorticoid receptor. Therefore, the primary effect of the receptor in glucocorticoid-mediated apoptosis correlates with transcriptional repression rather than activation and could be mediated by interference with other transcription factors required for cell survival.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Apoptosis / drug effects
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Apoptosis / genetics
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Apoptosis / physiology*
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Cell Division / drug effects
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Dexamethasone
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Gene Expression Regulation*
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Glucocorticoids / pharmacology*
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Humans
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Interleukin-2 / biosynthesis
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Interleukin-2 / genetics
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Leukemia
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Molecular Sequence Data
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Proto-Oncogene Proteins c-fos / biosynthesis
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Proto-Oncogene Proteins c-fos / genetics
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Proto-Oncogene Proteins c-jun / biosynthesis
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Proto-Oncogene Proteins c-jun / genetics
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Proto-Oncogene Proteins c-myc / biosynthesis
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Proto-Oncogene Proteins c-myc / genetics
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Receptors, Glucocorticoid / genetics
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Receptors, Glucocorticoid / physiology*
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Receptors, Retinoic Acid / genetics
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Receptors, Retinoic Acid / physiology
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Retinoic Acid Receptor alpha
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Signal Transduction
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T-Lymphocytes / physiology*
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Transcription Factor AP-1 / metabolism
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Transcriptional Activation
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Tretinoin / metabolism
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Tumor Cells, Cultured
Substances
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Glucocorticoids
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Interleukin-2
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Proto-Oncogene Proteins c-fos
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Proto-Oncogene Proteins c-jun
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Proto-Oncogene Proteins c-myc
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RARA protein, human
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Receptors, Glucocorticoid
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Receptors, Retinoic Acid
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Retinoic Acid Receptor alpha
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Transcription Factor AP-1
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Tretinoin
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Dexamethasone