Fig. 1
From: Cancer associated-fibroblast-derived exosomes in cancer progression
The origins and functions of CAFs in cancer progression. In the TME, CAFs can originate from resident fibroblasts by activation, epithelial cells following EMT, endothelial cells via EndMT, bone marrow-derived mesenchymal stem cells, pericytes, adipocytes and hepatic stellate cells by trans-differentiation. In most cases CAFs have cancer-promoting functions. CAFs play an important role in ECM remodeling by secreting ECM components and enzymes. CAFs can not only serve as physical barriers to protect the cancer cells from the external drugs and the attack of immune cells, but also secrete abundant soluble factors, EVs and ECM to regulate other cells type in TME, which include stimulating cancer cell proliferation, invasion and migration, angiogenesis and therapy resistance. Moreover, CAFs can regulate cancer cell metabolism and stimulate immune evasion of cancer cells