Transforming growth factor beta

Transforming growth factor beta is actually a group of dimeric proteins which all cells are capable of producing in vitro. Equally, most cells have receptors for TGF beta, permitting autocrine regulation.

Its in vitro activity seems to be complex:

• proliferation of fibroblasts
• chemotactic for fibroblasts and mononuclear phagocytes
• inhibition of cells such as keratinocytes and lymphocytes
• stimulation of collagen and fibronectin synthesis
• matrix formation by the inhibition of protease secretion

Overall, TGF beta tends to suppress immune function and as such, its secretion may be one means by which tumours bypass immunosurveillance. The isoforms TGF beta-1 and 2 are thought to be pro-fibrogenic whereas TGF beta-3 is anti-fibrogenic; they are being investigated as potential therapeutic targets for scarring treatments.