| Further Information: | TGF-?1 is a member of the transforming growth factor ? (TGF-?) family. The transforming growth factor-? family of polypeptides are involved in the regulation of cellular processes, including cell division, differentiation, motility, adhesion and death. TGF-?1 positively and negatively regulates many other growth factors. It inhibits the secretion and activity of many other cytokines including interferon-gamma, tumor necrosis factor-alpha and various interleukins. It can also decrease the expression levels of cytokine receptors. Meanwhile, TGF-?1 also increases the expression of certain cytokines in T cells and promotes their proliferation, particularly if the cells are immature. TGF-?1 also inhibits proliferation and stimulates apoptosis of B cells, and plays a role in controlling the expression of antibody, transferrin and MHC class II proteins on immature and mature B cells. As for myeloid cells, TGF-?1can inhibit their proliferation and prevent their production of reactive oxygen and nitrogen intermediates. However, as with other cell types, TGF-?1 also has the opposite effect on cells of myeloid origin. TGF-?1 is a multifunctional protein that controls proliferation, differentiation and other functions in many cell types. It plays an important role in bone remodeling as it is a potent stimulator of osteoblastic bone formation, causing chemotaxis, proliferation and differentiation in committed osteoblasts. Once cells lose their sensitivity to TGF-?1-mediated growth inhibition, autocrine TGF-? signaling can promote tumorigenesis. Elevated levels of TGF-?1 are often observed in advanced carcinomas, and have been correlated with increased tumor invasiveness and disease progression. |
