FIGURE 7.

Schematic diagram of ROS‐dependent MMT in PDAC. Monocytes in human blood are recruited into PDAC tissues. Low intracellular levels of H₂O₂ are important for fibronectin mRNA synthesis, protein expression, and secretion in monocytes and macrophages. Oxidative stressors, such as radiation, can reduce the phagocytic capacity and simultaneously activate the p38‐MAPK signaling pathway, thus inducing αSMA mRNA and protein expression in monocytes/macrophages. However, these cells do not express Col1. Therefore, myofibroblasts transdifferentiated from monocytes are characterized by low phagocytic capacity; high αSMA/Col1 levels; fibronectin, vimentin, FSP1, and CD68 expression; and features of inflammatory cells. In addition, supernatant from these cells can stimulate cancer cell (AsPC‐1) proliferation, thus promoting tumor progression in PDAC.

Abbreviations: MMT, monocyte‐to‐myofibroblast transdifferentiation; PDAC, pancreatic ductal adenocarcinoma; MAPK, mitogen‐activated protein kinase; Col1, collagen 1.