Cleavage of Fibulin-2 by the aggrecanases ADAMTS-4 and ADAMTS-5 contributes to the tumorigenic potential of breast cancer cells

Abstract

// Tania Fontanil 1, 2 , Saúl Álvarez-Teijeiro 2, 4 , M. Ángeles Villaronga 2, 4 , Yamina Mohamedi 1, 2 , Laura Solares 1, 2 , Angela Moncada-Pazos 1, 2, 8 , José A. Vega 3, 5 , Olivia García-Suárez 3 , Marcos Pérez-Basterrechea 6 , Juana M. García-Pedrero 2, 4 , Alvaro J Obaya 2, 7 , Santiago Cal 1, 2 1 Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Asturias Spain 2 Instituto Universitario de Oncología, IUOPA, Universidad de Oviedo, Asturias, Spain 3 Department of Morphology and Cellular Biology, Faculty of Medicine, University of Oviedo, Oviedo, Spain 4 Hospital Universitario Central de Asturias, Universidad de Oviedo, Asturias, and CIBERONC, Madrid, Spain 5 Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Chile 6 Unidad de Trasplantes, Terapia Celular y Medicina Regenerativa, Hospital Universitario Central de Asturias, Oviedo, Spain 7 Departamento de Biología Funcional, Area de Fisiología, Universidad de Oviedo, Asturias, Spain 8 Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom Correspondence to: Santiago Cal, email: santical@uniovi.es Keywords: extracellular matrix, aggrecanases, ADAMTS, metalloproteases, fibulin Received: August 04, 2016      Accepted: January 04, 2017      Published: January 13, 2017 ABSTRACT Fibulin-2 participates in the assembly of extracellular matrix components through interactions with multiple ligands and promotes contacts between cells and their surrounding environment. Consequently, identification of processes that could lead to an altered Fibulin-2 could have a major impact not only in the maintenance of tissue architecture and morphogenesis but also in pathological situations including cancer. Herein, we have investigated the ability of the secreted metalloproteases ADAMTS-4 and ADAMTS-5 to digest Fibulin-2. Using in vitro approaches and cultured breast cancer cell lines we demonstrate that Fibulin-2 is a better substrate for ADAMTS-5 than it is for ADAMTS-4. Moreover, Fibulin-2 degradation is associated to an enhancement of the invasive potential of T47D, MCF-7 and SK-BR-3 cells. We have also found that conditioned medium from MCF-7 cells that simultaneously overexpress Fibulin-2 and ADAMTS-5 significantly induced the migratory and invasive ability of normal breast fibroblasts using 3D collagen matrices. Immunohistochemical analysis highlights the close proximity or partial overlap of both Fibulin-2 and ADAMTS-5 in breast tumor samples. Additionally, proteolytic products derived from a potential degradation of Fibulin-2 by ADAMTS-5 were also identified in these samples. Finally, we also show that the cleavage of Fibulin-2 by ADAMTS-5 is counteracted by ADAMTS-12, a metalloprotease that interacts with Fibulin-2. Overall, our results provide direct evidence indicating that Fibulin-2 is a novel substrate of ADAMTS-5 and that this proteolysis could alter the cellular microenvironment affecting the balance between protumor and antitumor effects associated to both Fibulin-2 and the ADAMTSs metalloproteases.