title: Integrin-linked kinase functions as a downstream mediator of endothelin-1 to promote invasive behavior in ovarian carcinoma.
abstract: The endothelin-1 (ET-1) axis represents a novel target in several malignancies, including ovarian carcinoma. Upon being activated, the endothelin A receptor (ET(A)R) mediates multiple tumor-promoting activities, including mitogenesis, escape from apoptosis, angiogenesis, metastasis-related protease activation, epithelial-mesenchymal transition, and invasion. Integrin-linked kinase (ILK) is a multidomain focal adhesion protein that conveys intracellular signaling elicited by beta1-integrin and growth factor receptors. In this study, we investigate whether the signaling triggered by ET(A)R leading to an aggressive phenotype is mediated by an ILK-dependent mechanism. In HEY and OVCA 433 ovarian carcinoma cell lines, activation of ET(A)R by ET-1 enhances the expression of alpha2beta1 and alpha3beta1 integrins. ILK activity increases as ovarian cancer cells adhere to type I collagen through beta1 integrin signaling, and do so to a greater extent on ET-1 stimulation. ET-1 increases ILK mRNA and protein expression and activity in a time- and concentration-dependent manner. An ILK small-molecule inhibitor (KP-392) or transfection with a dominant-negative ILK mutant effectively blocks the phosphorylation of downstream signals, Akt and glycogen synthase kinase-3beta. The blockade of ET-1/ET(A)R-induced ILK activity results in an inhibition of matrix metalloproteinase activation as well as of cell motility and invasiveness in a phosphoinositide 3 kinase-dependent manner. In ovarian carcinoma xenografts, ABT-627, a specific ET(A)R antagonist, suppresses ILK expression, Akt and glycogen synthase kinase-3beta phosphorylation, and tumor growth. These data show that ILK functions as a downstream mediator of the ET-1/ET(A)R axis to potentiate aggressive cellular behavior. Thus, the ILK-related signaling cascade can be efficiently targeted by pharmacologic blockade of ET(A)R.
authors.affiliation: Laboratory of Molecular Pathology and Ultrastructure, Regina Elena Cancer Institute, Via delle Messi D'Oro 156, 00158 Rome, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Rosanò
authors.forename: Francesca
authors.initials: F
authors.lastname: Spinella
authors.forename: Valeriana
authors.initials: V
authors.lastname: Di Castro
authors.forename: Shoukat
authors.initials: S
authors.lastname: Dedhar
authors.forename: Maria Rita
authors.initials: MR
authors.lastname: Nicotra
authors.forename: Pier Giorgio
authors.initials: PG
authors.lastname: Natali
authors.forename: Anna
authors.initials: A
authors.lastname: Bagnato
mesh_terms: D000818:Animals; D001483:Base Sequence; D045744:Cell Line, Tumor; D002633:Chemotaxis; D017931:DNA Primers; D019332:Endothelin-1 / Q000502:physiology*; D005260:Female; D006801:Humans; D015151:Immunoblotting; D051379:Mice; D008819:Mice, Nude; D009361:Neoplasm Invasiveness; D010051:Ovarian Neoplasms / Q000473:pathology*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D044022:Receptor, Endothelin A / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014183:Transplantation, Heterologous; D000099200:Scaffold Protein ILK
chemical_list: D017931:DNA Primers; D019332:Endothelin-1; D017346:Protein Serine-Threonine Kinases; D034741:RNA, Small Interfering; D044022:Receptor, Endothelin A; D000099200:Scaffold Protein ILK