title: Engaged urokinase receptors enhance tumor breast cell migration and invasion by upregulating alpha(v)beta5 vitronectin receptor cell surface expression.
abstract: We have previously shown that urokinase receptor physically and functionally interacts with alpha(v)beta5 vitronectin receptor, leading to tumor breast cell migration and invasion. Here, the link between these 2 receptors was further investigated by analyzing the expression levels of urokinase receptor and alpha(v)beta5 integrin in 35 human breast carcinomas and 5 benign breast lesions. The occurrence of a positive correlation between urokinase receptor and alpha(v)beta5 protein levels in benign and malignant tumor specimens prompted us to investigate whether engaged urokinase receptors might modulate alpha(v)beta5 expression. Here, we report the receptor-dependent ability of catalytically inactive urokinase to upregulate the alpha(v) and beta5 chains in MDA-MB-231 and MCF-7 breast carcinoma cell lines in a time- and concentration-dependent manner. This effect is dependent on protein kinase C activity and requires new protein synthesis. Accordingly, the availability of assembled alpha(v)beta5 receptors on the cell surface increases upon urokinase treatment, as shown by immunoprecipitation and immunocytochemical analyses. Exposure to urokinase leads to enhanced tumor cell migration and invasion, which is prevented by the "phosphorylation-like" urokinase receptor antagonist His-uPA(138E/303E), the DNA-binding drug mithramycin, the protein kinase C inhibitor calphostin C and anti-alpha(v)beta5 antibodies. Finally, urokinase enables benign breast MCF-10A cells to cross Matrigel in a alpha(v)beta5- and urokinase receptor-dependent manner, indicating that urokinase controls a regulatory circuitry crucial to breast tumor progression.
authors.affiliation: Department of Experimental Oncology, National Cancer Institute of Naples, Naples, Italy.
authors.forename: Immacolata
authors.initials: I
authors.lastname: Silvestri
authors.forename: Immacolata
authors.initials: I
authors.lastname: Longanesi Cattani
authors.forename: Paola
authors.initials: P
authors.lastname: Franco
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pirozzi
authors.forename: Gerardo
authors.initials: G
authors.lastname: Botti
authors.forename: Maria Patrizia
authors.initials: MP
authors.lastname: Stoppelli
authors.forename: Maria Vincenza
authors.initials: MV
authors.lastname: Carriero
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000737:chemistry / Q000378:metabolism / Q000473:pathology*; D002465:Cell Movement; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D039302:Integrin alphaVbeta3 / Q000032:analysis / Q000096:biosynthesis*; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011956:Receptors, Cell Surface / Q000032:analysis / Q000502:physiology*; D055293:Receptors, Urokinase Plasminogen Activator; D015854:Up-Regulation; D014568:Urokinase-Type Plasminogen Activator / Q000494:pharmacology
chemical_list: D039302:Integrin alphaVbeta3; C524898:PLAUR protein, human; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator