title: Agonist and antagonist of retinoic acid receptors cause similar changes in gene expression and induce senescence-like growth arrest in MCF-7 breast carcinoma cells.
abstract: Biological effects of retinoids are mediated via retinoic acid (RA) receptors (RAR) and retinoid X receptors (RXR). The best-characterized mechanism of retinoid action is stimulation of transcription from promoters containing RA response elements (RARE). Retinoids induce senescence-like growth arrest in MCF-7 breast carcinoma cells; this effect is associated with the induction of several growth-inhibitory genes. We have now found that these genes are induced by RAR-specific but not by RXR-specific ligands. Genome-scale microarray analysis of gene expression was used to compare the effects of two pan-RAR ligands, one of which is a strong agonist of RARE-dependent transcription, whereas the other induces such transcription only weakly and antagonizes the inducing effect of RAR agonists. Both RAR ligands, however, produced very similar effects on gene expression in MCF-7 cells, suggesting that RARE-dependent transcription is only a minor component of retinoid-induced changes in gene expression. The effects of RAR ligands on gene expression parallel changes associated with damage-induced senescence, and both ligands induced G(1) arrest and the senescent phenotype in MCF-7 cells. The RAR ligands up-regulated many tumor-suppressive genes and down-regulated multiple genes with oncogenic activities. Genes that are strongly induced by RAR ligands encode secreted bioactive proteins, including several tumor-suppressing factors. In agreement with these observations, retinoid-treated MCF-7 cells inhibited the growth of retinoid-insensitive MDA-MB-231 breast carcinoma cells in coculture. These results indicate that RARE-independent transcriptional effects of RAR ligands lead to senescence-like growth arrest and paracrine growth-inhibitory activity in MCF-7 breast carcinoma cells.
authors.affiliation: Cancer Center, Ordway Research Institute, Albany, NY 12208, USA.
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Chen
authors.forename: Milos
authors.initials: M
authors.lastname: Dokmanovic
authors.forename: Wilfred D
authors.initials: WD
authors.lastname: Stein
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Ardecky
authors.forename: Igor B
authors.initials: IB
authors.lastname: Roninson
mesh_terms: D000199:Actins / Q000235:genetics; D000970:Antineoplastic Agents / Q000494:pharmacology; D001943:Breast Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology*; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D016922:Cellular Senescence / Q000187:drug effects; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis; D018168:Receptors, Retinoic Acid / Q000819:agonists* / Q000037:antagonists & inhibitors; D012176:Retinoids / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D000199:Actins; D000970:Antineoplastic Agents; D005231:Fatty Acids, Unsaturated; D018168:Receptors, Retinoic Acid; D012176:Retinoids; C062198:octa-2,4,6-trienoic acid