IGF-I induces upregulation of DDR1 collagen receptor in breast cancer cells by suppressing MIR-199a-5p through the PI3K/AKT pathway

// Roberta Mata 1, * , Chiara Palladino 1, * , Maria Luisa Nicolosi 1 , Anna Rita Lo Presti 1 , Roberta Malaguarnera 1 , Marco Ragusa 2 , Daniela Sciortino 1 , Andrea Morrione 3 , Marcello Maggiolini 4 , Veronica Vella 5, 6 , Antonino Belfiore 1 1 Endocrinology, Department of Health Sciences, University Magna Graecia of Catanzaro, Catanzaro, Italy 2 Department of Biomedical and Biotechnological Sciences Biology, Genetics and BioInformatics Unit, University of Catania, Catania, Italy 3 Department of Urology and Biology of Prostate Cancer Program, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA 4 Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy 5 Motor Sciences, School of Human and Social Sciences, “Kore” University of Enna, Enna, Italy 6 Department of Clinical and Molecular Bio-Medicine, Endocrinology Unit, University of Catania, Garibaldi-Nesima Medical Center, Catania, Italy * These authors contributed equally to this work Correspondence to: Antonino Belfiore, e-mail: belfiore@unicz.it Keywords: IGF-IR, insulin-like growth factor-I receptor, DDR1, breast cancer Received: August 01, 2015      Accepted: November 16, 2015      Published: December 09, 2015 ABSTRACT Discoidin Domain Receptor 1 (DDR1) is a collagen receptor tyrosine-kinase that contributes to epithelial-to-mesenchymal transition and enhances cancer progression. Our previous data indicate that, in breast cancer cells, DDR1 interacts with IGF-1R and positively modulates IGF-1R expression and biological responses, suggesting that the DDR1-IGF-IR cross-talk may play an important role in cancer. In this study, we set out to evaluate whether IGF-I stimulation may affect DDR1 expression. Indeed, in breast cancer cells (MCF-7 and MDA-MB-231) IGF-I induced significant increase of DDR1 protein expression, in a time and dose dependent manner. However, we did not observe parallel changes in DDR1 mRNA. DDR1 upregulation required the activation of the PI3K/AKT pathway while the ERK1/2, the p70/mTOR and the PKC pathways were not involved. Moreover, we observed that DDR1 protein upregulation was induced by translational mechanisms involving miR-199a-5p suppression through PI3K/AKT activation. This effect was confirmed by both IGF-II produced by cancer-associated fibroblasts from human breast cancer and by stable transfection of breast cancer cells with a human IGF-II expression construct. Transfection with a constitutively active form of AKT was sufficient to decrease miR-199a-5p and upregulate DDR1. Accordingly, IGF-I-induced DDR1 upregulation was inhibited by transfection with pre-miR-199a-5p, which also impaired AKT activation and cell migration and proliferation in response to IGF-I. These results demonstrate that, in breast cancer cells, a novel pathway involving AKT/miR-199a-5p/DDR1 plays a role in modulating IGFs biological responses. Therefore, this signaling pathway may represent an important target for breast cancers with over-activation of the IGF-IR axis.