title: Tyrosine kinase signaling pathways control the expression of retinoic acid receptor-alpha in SK-BR-3 breast cancer cells.
abstract: Breast carcinomas are frequently characterized by hyperactivated c-erbB receptor tyrosine kinase signaling. Combination of anti-proliferative retinoids with growth-inhibitory c-erbB-specific agents might induce therapeutic benefit. We demonstrate close interactions between the c-erbB and the retinoic acid receptor system in SK-BR-3 breast cancer cells. Epidermal growth factor and heregulin-beta1 activate c-erbB receptors and dose- and time-dependently up-regulate retinoic acid receptor-alpha (RAR-alpha) mRNA. Similar effects have been found for the growth-inhibitory c-erbB-2 receptor tyrosine kinase-activating antibody 4D5 and the tyrosine phosphatase inhibitor orthovanadate. In contrast, the tyrosine kinase-inhibitor herbimycin A reduces tyrosine-specific protein phosphorylation and down-regulates RAR-alpha. Our data demonstrate that the expression of RAR-alpha, which represents a key mediator of the anti-proliferative effects of retinoids in breast cancer cells, is regulated by modulators of tyrosine kinase signaling. The levels of RAR-beta and -gamma mRNAs, however, are not affected by such agents.
authors.affiliation: Department of Internal Medicine I, University of Vienna, Austria.
authors.forename: S H
authors.initials: SH
authors.lastname: Flicker
authors.forename: S M
authors.initials: SM
authors.lastname: Schneider
authors.forename: M
authors.initials: M
authors.lastname: Offterdinger
authors.forename: E
authors.initials: E
authors.lastname: Dittrich
authors.forename: B
authors.initials: B
authors.lastname: Fazeny
authors.forename: R
authors.initials: R
authors.lastname: Valenta
authors.forename: H
authors.initials: H
authors.lastname: Huber
authors.forename: C
authors.initials: C
authors.lastname: Dittrich
authors.forename: T W
authors.initials: TW
authors.lastname: Grunt
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D006801:Humans; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D018168:Receptors, Retinoic Acid / Q000378:metabolism*; D000072482:Retinoic Acid Receptor alpha; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
chemical_list: D011505:Protein-Tyrosine Kinases; D018719:Erb-b2 Receptor Tyrosine Kinases; D018168:Receptors, Retinoic Acid; D000072482:Retinoic Acid Receptor alpha; C000607071:RARA protein, human