title: Validation of VX2 as a Hepatocellular Carcinoma Model: Comparison of the Molecular Reaction of VX2 and HepG2 Tumor Cells to Sorafenib In Vitro.
abstract: As there is currently no superior hepatocellular carcinoma (HCC) model with percutaneous vascular access for transarterial treatments available, the VX2 rabbit model is frequently used for in vivo investigations on liver carcinoma. However, the VX2 cell line was derived from a virus-induced skin papilloma that can form carcinosarcoma in liver of rabbits and the transferability of obtained results to HCC treatment remains open. Here we compared the most frequently investigated human HCC model cell line, HepG2, with VX2 cells in vitro in terms of sensitivity towards the broad specificity kinase inhibitor sorafenib and responsiveness to the addition of platelet-derived growth factor AB (PDGF-AB), vascular endothelial growth factor (VEGF) and hepatic growth factor (HGF), as well as insulin and interleukin-1β (IL1β). Phosphorylation of protein kinase B (AKT) the mitogen-activated protein kinases (MAPKs) p38 and p42/44 (extracellular signal-regulated kinase, ERK1/2) and inhibitor of kappa light chain gene enhancer alpha (IĸBα) was determined by western blotting as these events are associated with early signaling cascades. Additionally, the inhibition of phosphorylation under sorafenib treatment was investigated. Sorafenib was equally toxic to both cell lines, but only in HepG2 was activation of caspase 3/7 activity, as a sign of apoptosis, observed. VX2 cells exhibited generally more intense phosphorylation signals in response to the growth factors and also serum. In contrast to VX2, HepG2 cells showed no response to PDGF-AB or VEGF as determined by kinase phosphorylation. In both cell lines, sorafenib inhibited growth factor-induced phosphorylation of ERK and p38-MAPK. AKT phosphorylation was only inhibited in VX2 cells and IĸBα phosphorylation was not influenced by this kinase inhibitor in either cell type. Taken together, the two cellular models for HCC share several features related to sorafenib application, but differed in their responsiveness towards growth factors. Therefore, results obtained with the VX2 model cannot be extended to human HCC without appropriate caution.
authors.affiliation: Institute of Pathology, Otto von Guericke University Magdeburg, Magdeburg, Germany norbert.nass@med.ovgu.de.
authors.forename: Norbert
authors.initials: N
authors.lastname: Nass
authors.affiliation: Department of Radiology and Nuclear Medicine, Otto von Guericke University Magdeburg, Magdeburg, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Streit
authors.affiliation: Department of Radiology and Nuclear Medicine, Otto von Guericke University Magdeburg, Magdeburg, Germany.|Institute of Diagnostic and Interventional Radiology, University Hospital of Cologne, Cologne, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Wybranski
authors.affiliation: Department of Radiology and Nuclear Medicine, Otto von Guericke University Magdeburg, Magdeburg, Germany.
authors.forename: Julian
authors.initials: J
authors.lastname: Jürgens
authors.affiliation: Department of Radiology and Nuclear Medicine, Otto von Guericke University Magdeburg, Magdeburg, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Brauner
authors.affiliation: Department of Radiology and Nuclear Medicine, Otto von Guericke University Magdeburg, Magdeburg, Germany.
authors.forename: Nadine
authors.initials: N
authors.lastname: Schulz
authors.affiliation: Department of Radiology and Nuclear Medicine, Otto von Guericke University Magdeburg, Magdeburg, Germany.
authors.forename: Maciej
authors.initials: M
authors.lastname: Powerski
authors.affiliation: Department of Radiology and Nuclear Medicine, Otto von Guericke University Magdeburg, Magdeburg, Germany.|International School of Image-Guided Interventions, Magdeburg, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Ricke
authors.affiliation: Institute of Pathology, Otto von Guericke University Magdeburg, Magdeburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kalinski
authors.affiliation: Department of Radiology and Nuclear Medicine, Otto von Guericke University Magdeburg, Magdeburg, Germany.|International School of Image-Guided Interventions, Magdeburg, Germany.|Hirslanden Private Hospital Group, Radiology Clinic, Centre for Microtherapy, Zurich, Switzerland.
authors.forename: Oliver
authors.initials: O
authors.lastname: Dudeck
authors.affiliation: Department of Radiology and Nuclear Medicine, Otto von Guericke University Magdeburg, Magdeburg, Germany.|International School of Image-Guided Interventions, Magdeburg, Germany.
authors.forename: Max
authors.initials: M
authors.lastname: Seidensticker
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D056945:Hep G2 Cells; D017228:Hepatocyte Growth Factor / Q000494:pharmacology; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D053583:Interleukin-1beta / Q000494:pharmacology; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D009536:Niacinamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D010641:Phenotype; D010671:Phenylurea Compounds / Q000494:pharmacology*; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011817:Rabbits; D015398:Signal Transduction / Q000187:drug effects; D000077157:Sorafenib; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D007328:Insulin; D053583:Interleukin-1beta; D010671:Phenylurea Compounds; D010982:Platelet-Derived Growth Factor; D047428:Protein Kinase Inhibitors; D042461:Vascular Endothelial Growth Factor A; C095477:platelet-derived growth factor AB; D009536:Niacinamide; D017228:Hepatocyte Growth Factor; D000077157:Sorafenib; D011505:Protein-Tyrosine Kinases
keywords: HepG2; VX2; hepatocellular carcinoma; in vitro models; mitogen activated protein kinase (MARK); protein kinase B (ACT); sorafenib