Breast cancer metastasis is the main cause of related deaths. Most of them originate from triple negative ones. No targeted therapies are reported to be efficient in this type of cancer until now. The extracellular matrix (ECM), and in particular the fibronectin type I motif IGDQ, plays a major role in cell migration prior the metastasis formation. This motif interacts with specific integrins inducing their activation and the migratory signal transduction. In this work, known as PACMAN (Peptide-Assisted Cellular Migration Along eNgineered surfaces) project, we have shown, in an in vitro model of cell migration (Marega et al, Small (2016)), that IGDQ-exposing (IsoLeu-Gly-Asp-Glutamine type I Fibronectin motif) monolayers (SAMs) on gold sustain the adhesion of MDA-MB-231 cells by triggering Focal Adhesion Kinase by activating integrins. The observed migratory behavior induced by the IGDQ-bearing peptide gradient along the surface suggests the presence of cell subpopulations associated with a “stationary” or a “migratory” phenotype, the latter determining a considerable cell migration at the sub-cm length scale. First, we investigated the role of integrin alpha 5 and integrin beta 3 in collective and IGDQ-mediated single cell migration using shRNA method and a complete proteomic analysis. Our results showed that i) beta 3 integrin depletion influences integrin alpha 5 mRNA expression, ii) integrin beta 3 and integrin alpha 5 are both necessary for IGDQ-mediated directional single cell migration, iii) integrin (αv)β3 is activated by IGDQ fibronectin type I motif and iv) co-regulation of retrograde transport of integrin beta 3 by integrin alpha 5 is potentially necessary for directional IGDQ-mediated cell migration. Secondly, we characterized the migratory phenotype of MDA-MB-231 cells, using functionalized IGDQ-exposing surfaces, and compared it to integrin alpha 5 and integrin beta 3 knock-down cells. The serine and arginine rich splicing factor 6 (SRSF6) was found to be functionally linked to both integrins and cell migration. Indacaterol was evidenced as a direct pharmacology inhibitor of SRSF6. The incubation of cells with indacaterol induced: i) the inhibition of collective and IGDQ-mediated cell migration and ii) ITGA5 sequestration into endosomes and lysosomes. Indacaterol is a thus potential therapy to block cell migration and reduce metastasis formation. Using IGDQ-exposing surfaces to highlight the mechanisms involved in integrins trafficking in cell migration will help to highlight potential targets or biomarkers to prevent metastasis in cancer patients.
Characterization of the migratory phenotype of cancer cells selected on IGDQ expressing surface: “PACMAN" project
Ayama, S. (Auteur). 2021
Student thesis: Doc types › Docteur en Sciences