Figures & data
Figure 1. The fatal alliance of T cells and pancreatic ductal epithelial cancer cells in inflammation-associated PDAC development. Upon pancreatic inflammation CD4+ T cells, most likely T effector cells (Teffs) but also regulatory T cells (Tregs), infiltrate the pancreatic tissue where they come in contact with the pancreatic ductal epithelium. Teffs promote epithelial-mesenchymal transition (EMT)-associated alterations along with enhanced L1CAM expression in pancreatic ductal epithelium by releasing inflammatory cytokines such as TNFα, IL-1β, and IL-6. Tregs add to this scenario via the release of TGFβ1. However, Teffs still efficiently produce IL-2 and IFNγ enabling T helper cell type 1 (Th1)-activity. Still expressed at moderate levels, L1CAM increases tumorigenicity, invasiveness and apoptotic resistance of premalignant epithelial cells in precursor lesions or chronic pancreatitis (CP). However, these effects are even more pronounced in pancreatic ductal adenocarcinoma (PDAC) cells exhibiting strong L1CAM expression. Furthermore, these elevated L1CAM expression levels contribute to the enrichment of immunosuppressive T cells by promoting migration/infiltration of CD4+CD25+CD127-CD49d- Tregs into the pancreas, impairing the proliferation of Teffs and favoring the generation of immunosuppressive CD4+CD25-CD69+ T cells.
