TY - JOUR T1 - The Cten signalling pathway stabilises Src protein to promote Epithelial-Mesenchymal Transition (EMT) in colorectal cancer JF - bioRxiv DO - 10.1101/458109 SP - 458109 AU - Abdulaziz Asiri AU - Michael S Toss AU - Teresa Pereira Raposo AU - Maham Akhlaq AU - Hannah Thorpe AU - Abdulaziz Alfahed AU - Abutaleb Asiri AU - Mohammad Ilyas Y1 - 2018/01/01 UR - http://biorxiv.org/content/early/2018/10/31/458109.abstract N2 - Cten is an oncogene which promotes epithelial-mesenchymal transition (EMT) in many signalling pathways. Having previously shown that Cten promotes EMT through Snail, we investigated whether Cten function could be mediated through Src (a known regulator of Snail).Cten levels were modulated by forced expression in colorectal cancer (CRC) cell lines with low Cten expression (HCT116 and RKO) and gene knockdown in a cell line with high Cten expression (SW620). In all cell lines, Cten was a positive regulator of Src expression. The functional importance of Src was tested by forcibly expressing Cten and simultaneously knocking down Src. This resulted in abrogation of Cten motility-inducing activity (cell migration, cell invasion, wound healing – each p<0.001) and abrogation of the promotion of colony formation by Cten (p<0.001) together with failure to induce the Cten targets - Snail and ROCK1. To complement these experiments, Cten expression was restored by forced expression in a subclone of SW620 in which the Cten gene had been deleted (SW620ΔCten). SW620ΔCten showed reduced expression of Src which increased following restoration of Cten by forced expression. In SW620ΔCten, restoration of Cten increased cell motility (cell migration, cell invasion, wound healing) and colony formation (each p<0.001) which were all lost if Src was concomitantly knocked down. Quantitative Reverse-Transcription PCR (qRT-PCR) showed that modulation of Cten had no effect on Src mRNA levels. However, a cycloheximide (CHX) pulse chase assay demonstrated stabilisation of Src protein by Cten. Finally, the expression of Cten and Src was tested in a series of 84 primary CRCs and there was significant correlation between Cten and Src expression (p=0.001).We conclude that Src is a novel and functionally important target of the Cten signalling pathway and that Cten protein causes post-transcriptional stabilisation of Src protein in order to promote EMT and possibly metastasis in CRC. ER -