BioProject

The transcription factor SNAIL1 is a master regulator of epithelial-to-mesenchymal transition, a process entailing massive gene expression changes. More...

The transcription factor SNAIL1 is a master regulator of epithelial-to-mesenchymal transition, a process entailing massive gene expression changes. To better understand SNAIL1-induced transcriptional reprogramming we performed time-resolved transcriptome analysis upon conditional SNAIL1 expression in colorectal cancer cells. Bioinformatic analyses indicated that SNAIL1 strongly affected Wnt/β-Catenin pathway activity. This correlated with upregulation of LEF1, a nuclear binding partner of β-Catenin. Several tumour entities, including aggressive mesenchymal colorectal cancers, exhibit positively correlated LEF1 and SNAIL1 expression, and elevated LEF1 levels parallel increased colorectal cancer patient mortality. Comparative gene expression profiling suggested that 35% of Snail1-induced transcriptional changes are attributable to LEF1. LEF1 stimulates Wnt/β-Catenin pathway feedback inhibitor expression, causes cell-cycle arrest in vitro, and retards xenograft tumour growth. Conversely, LEF1-deficiency and preventing the β-Catenin-LEF1 interaction impaired the ability of SNAIL1 to alter Wnt/β-catenin target gene expression and to induce cancer cell invasion. Although LEF1 did not autonomously induce epithelial-mesenchymal transition, LEF1 is a critical factor acting downstream of SNAIL1. Apparently, SNAIL1 employs LEF1 as alternative effector to redirect Wnt/β-catenin pathway activity towards anti-proliferative and pro-invasive gene expression. Overall design: Total RNA was extracted from either SNAI1 or LEF1 overexpression parental LS174T colorectal carcinoma cells at 0,3,6,24,48,72 or 96 hours after induction with Dox. Less...