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. Author manuscript; available in PMC: 2010 Jul 9.
Published in final edited form as: Oncogene. 2009 Aug 31;28(45):4022–4033. doi: 10.1038/onc.2009.253

Figure 3.

Figure 3

Transforming growth factor-β (TGF-β) and platelet-derived growth factor (PDGF) secretion in the hepatic tumor microenvironment. Amounts of secreted TGF-β1 and PDGF-AA were determined in triplicate and plotted as nanogram and picogram per millilitre supernatant per 106 cells, respectively. (a) TGF-β stimulation of malignant hepatocytes induces their TGF-β secretion, suggesting induction of an autocrine TGF-β loop. (b) As a downstream event, TGF-β strongly induces PDGF-AA secretion, except in MIM-S35-dn-P cells, in which induction is less than twofold and not significant. PDGF-AA secretion is lowered by interfering with PDGF receptor (PDGF-R), verifying an autocrine PDGF loop. (c) in vivo-activated myofibroblasts (Mdr2-p19) show higher levels of secreted TGF-β1 and (d) PDGF-AA than in vitro-activated fibroblasts (M-HT). Comparable results were obtained in another independent experiment *P<0.05; **P<0.01; ***P<0.005.