Connexin43-Src interacting sequence as a cell-penetrating peptide to study human primary glioma stem cells invasion

Resumen del trabajo presentado al XXXXVIII Congreso de la Sociedad Española de Bioquímica y Biología Molecular (SEBBM), celebrado en Valencia del 7 al 10 de septiembre de 2015.Connexin43 (Cx43) is the main gap junction channel-forming protein in astrocytes, the most abundant glial cells in central nervous system. This protein is downregulated in brain tumours called gliomas. Tumour initiation, relapse, and therapeutic resistance in gliomas is attributed to Glioma Stem Cells (GSCs). Interestingly, several cell-penetrating peptides (CPPs) containing different regions of Cx43 involved in c-Src interaction reverse Glioma Stem Cells (GSCs) phenotype and reduce the rate of cell growth. Considering the controversial Cx43 migration properties and the infi ltrative nature of these tumours, we have investigated the role of these CPPs in human primary GSC migration and invasion. Human primary GSCs were obtained from fresh tumour biopsies and were treated with CPPs. Human GSCs G166 were treated with CPPs. Migration was studied using tiny-tumour cultures, Time-Lapse live-cell Imaging and Immunocytochemistry. Invasion was studied using 8.0 μM pore transwell inserts with or without Matrigel. The mechanism involved in migration was studied by Western blot, evaluating the activity of Focal Adhesion Kinase (FAK). Our findings indicate that our CPPs reduced the rate of human primary GSCs and G166 GSCs migration and invasion. In addition, CPPs inhibited c-Src activity in these cells and consequently decreased FAK phosphorylation necessary to establish adequate focal adhesions in order to migrate. It should be mentioned that FAK is activated by Src-mediated phosphorylation. In conclusion, our results show that c-Src plays an essential role in the effects of Cx43 on migration and suggest these CPPs by inhibiting migration and invasion could be the basis for promising therapies.Peer reviewe