Bacterial genotoxins, Cytolethal Distending Toxin (CDT) and colibactin, cause DNA damage in intoxicated epithelial cells of the host. DNA damage influences {beta}?catenin signaling, altering its stability and nuclear translocation, potentially contributing to cancer development. Using non-transformed hepatocytes and cancer-derived intestinal and hepatic epithelial cell lines, we showed that CDT/CdtB induces the phosphorylation of {beta}catenin at serine 552, along with the loss of {beta}catenin from adherens junctions. This leads to the subsequent cytoplasmic accumulation and nuclear translocation of {beta}catenin, ultimately driving TCF/LEF transcription, the crucial downstream event of Wnt/{beta}catenin signaling, as well as the transcription of some {beta}catenin target genes. Colibactin induces similar effects. MK-2206, a direct AKT inhibitor, and metformin, an AMP-activated protein kinase activator that indirectly inhibits AKT, both protected cells against various effects induced by CdtB exposure. These effects include {beta}catenin phosphorylation at Ser552, the disassembly of cell-cell junctions and the subsequent nuclear accumulation of phosphorylated {beta}catenin, leading to reduced TCF/LEF-mediated transcription. Additionally, MK-2206 and metformin protected from CdtB-induced epithelial-mesenchymal transition (EMT), including increased nuclear accumulation of SNAIL, enhanced matrix degradation and motility. Overall, these data show that infection with genotoxin-producing bacteria controls some EMT features through {beta}catenin and AKT-dependent signaling.
JIA, R., Azzi-Martin, L., Saraiva, M., Sifre, E., Varon, C., Dubus, P., Menard, A.
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