Fig. 8.
Action of decorin on PDGF signaling in experimental liver cancer. The action of TGFβ is known to upregulate PDGF ligands. The presence of decorin hinders both Smad-dependent and independent signaling from the TGFβ receptor leading to decreased expression of PDGFs. In the extracellular environment, decorin may prevent PDGF from binding to its receptors resulting in an interference with downstream signaling. PDGF may act in an autocrine or a paracrine fashion. The changes in ERK1/2 upon the presence or absence of decorin, can be an outcome of crosstalk between the different growth factor receptors. Decorin utilizes p21WAF1/CIP1 for blockade of cell cycle to display its tumor repressor effect in most model systems.