Abstract
The Ras/Raf/MEK/ERK signaling pathway plays an important role in progression and angiogenesis of hepatocellular carcinoma (HCC). In addition, STAT3 is a central promoter of HCC growth. Both signaling pathways are also involved in motility and proliferation of endothelial cells. We hypothesized that dual inhibition of B-Raf and VEGFR2 with small molecule inhibitor (NVP-AAL881) will affect tumor cells, endothelial cells and pericytes thereby reducing tumor growth and angiogenesis of HCC in vivo. Human HCC cell lines (HepG2, Huh-7), endothelial cells (HUVEC) and pericytes (vascular smooth muscle cells, VSMC) were used for the experiments. A small molecule inhibitor (NVPAAL881, Novartis, Basel) was used for simultaneously blocking B-Raf kinase and VEGFR2. Cytotoxic effects in vitro were determined using MTT assays. Effects of NVP-AAL881 on activation of signaling intermediates (MEK, ERK) and STAT3 in tumor cells and EC were investigated by Western blotting. Changes in constitutive and growth factor induced migration of HCC cells, EC and VSMC were evaluated in Boyden chamber assays. Effect of combined B-Raf/VEGFR2-blockade on tumor growth were subsequently determined in a subcutaneous tumor model. Blockade of Raf in HCC cells blocked activation of MEK, ERK and STAT3. In addition, constitutive and growth factor induced tumor cell migration and invasion were significantly reduced (P < 0.05). In EC, NVP-AAL881 diminished activation of AKT, ERK as well as VEGFR2-independent STAT3 activation. Furthermore, migration and proliferation of EC and VSMC were significantly reduced (P < 0.05). In the subcutaneous model, tumor growth was significantly inhibited (P < 0.05). Immunohistological analyses revealed a marked reduction of CD31 vessel area in NVP-AAL881 treated tumors. In conclusion, combined inhibition of B-Raf and VEGFR2 efficiently reduces tumor growth and vascularization of HCC in vivo and, therefore, might be a promising approach for molecular-based therapy of HCC.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Literatur
Semela D, Dufour JF (2004) Angiogenesis and hepatocellular carcinoma. J Hepatol, 41: 864–880
Schmidt CM, McKillop IH, Cahill PA, Sitzmann JV (1997) Increased MAPK expression and activity in primary human hepatocellular carcinoma. Biochem Biophys Res Commun, 236: 54–58
Yang SF, Wang SN, Wu CF, Yeh YT, Chai CY, Chunag SC, Sheen MC, Lee KT (2007) Altered p-STAT3 (tyr705) expression is associated with histological grading and intratumour microvessel density in hepatocellular carcinoma. J Clin Pathol, 60: 642–648
Yahata Y, Shirakata Y, Tokumaru S, Yamasaki K, Sayama K, Hanakawa Y, Detmar M, Hashimoto K (2003) Nuclear translocation of phosphorylated STAT3 is essential for vascular endothelial growth factor-induced human dermal microvascular endothelial cell migration and tube formation. J Biol Chem, 278: 40026–40031
Culmsee C, Gasser E, Hansen S, Tonn JC, Wagner E, Goldbrunner R (2006) Effects of Raf-1 siRNA on human cerebral microvascular endothelial cells: a potential therapeutic strategy for inhibition of tumor angiogenesis. Brain Res, 1125: 147–154
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2008 Springer Medizin Verlag Heidelberg
About this paper
Cite this paper
Lang, S.A. et al. (2008). Duale Inhibition von B-Raf und VEGFR2 reduziert die Vaskularisierung und das Wachstum des hepatozellulären Karzinoms. In: Arbogast, R., Schackert, H.K., Bauer, H. (eds) Chirurgisches Forum 2008. Deutsche Gesellschaft für Chirurgie, vol 37. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-78833-1_1
Download citation
DOI: https://doi.org/10.1007/978-3-540-78833-1_1
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-78821-8
Online ISBN: 978-3-540-78833-1
eBook Packages: Medicine (German Language)