Plasminogen fragment K1-5 improves survival in a murine hepatocellular carcinoma model

Anti‑angiogenesis gene therapy for hepatocellular carcinoma via systemic injection of mesenchymal stem cells engineered to secrete soluble Flt‑1

Anti‑angiogenesis gene therapy has attracted interest as a potential treatment for hepatocellular carcinoma (HCC). Studies have indicated that soluble fms‑like tyrosine kinase‑1 (sFlt‑1) may suppress angiogenesis by sequestering free vascular endothelial growth factor (VEGF) or by forming inactive heterodimers with VEGF receptor‑2. Mesenchymal stem cells (MSCs) have been widely used as prospective delivery vehicles for therapeutic agents, owing to their ability to migrate towards tumor sites. In the present study, a subcutaneous HCC mouse model was used to assess the anti‑angiogenesis effects of lentivirus‑transfected MSCs engineered to secrete sFlt‑1 (LV‑sFlt‑1‑MSCs). LV‑sFlt‑1‑MSCs effectively secreted sFlt‑1, which inhibited tube formation in vitro. MSCs labeled with green fluorescence protein primarily migrated to tumor sites in vivo. An immunohistochemical assay indicated that microvessel density was reduced in mice treated with LV‑sFlt‑1‑MSCs, compared with the control group treated with PBS. Additionally, LV‑sFlt‑1‑MSCs inhibited tumor growth and prolonged survival in an HCC mouse model via systemic injection. Overall, the present study was designed to investigate the potential of LV‑sFlt‑1‑MSCs for anti‑angiogenesis gene therapy in HCC.

Statins activate the canonical hedgehog-signaling and aggravate non-cirrhotic portal hypertension, but inhibit the non-canonical hedgehog signaling and cirrhotic portal hypertension

Liver cirrhosis but also portal vein obstruction cause portal hypertension (PHT) and angiogenesis. This study investigated the differences of angiogenesis in cirrhotic and non-cirrhotic PHT with special emphasis on the canonical (Shh/Gli) and non-canonical (Shh/RhoA) hedgehog pathway. Cirrhotic (bile duct ligation/BDL; CCl₄ intoxication) and non-cirrhotic (partial portal vein ligation/PPVL) rats received either atorvastatin (15 mg/kg; 7d) or control chow before sacrifice. Invasive hemodynamic measurement and Matrigel implantation assessed angiogenesis in vivo. Angiogenesis in vitro was analysed using migration and tube formation assay. In liver and vessel samples from animals and humans, transcript expression was analyzed using RT-PCR and protein expression using Western blot. Atorvastatin decreased portal pressure, shunt flow and angiogenesis in cirrhosis, whereas atorvastatin increased these parameters in PPVL rats. Non-canonical Hh was upregulated in experimental and human liver cirrhosis and was blunted by atorvastatin. Moreover, atorvastatin blocked the non-canonical Hh-pathway RhoA dependently in activated hepatic steallate cells (HSCs). Interestingly, hepatic and extrahepatic Hh-pathway was enhanced in PPVL rats, which resulted in increased angiogenesis. In summary, statins caused contrary effects in cirrhotic and non-cirrhotic portal hypertension. Atorvastatin inhibited the non-canonical Hh-pathway and angiogenesis in cirrhosis. In portal vein obstruction, statins enhanced the canonical Hh-pathway and aggravated PHT and angiogenesis.

Proteome mapping of epidermal growth factor induced hepatocellular carcinomas identifies novel cell metabolism targets and mitogen activated protein kinase signalling events

Background

Hepatocellular carcinoma (HCC) is on the rise and the sixth most common cancer worldwide. To combat HCC effectively research is directed towards its early detection and the development of targeted therapies. Given the fact that epidermal growth factor (EGF) is an important mitogen for hepatocytes we searched for disease regulated proteins to improve an understanding of the molecular pathogenesis of EGF induced HCC. Disease regulated proteins were studied by 2DE MALDI-TOF/TOF and a transcriptomic approach, by immunohistochemistry and advanced bioinformatics.

Results

Mapping of EGF induced liver cancer in a transgenic mouse model identified n = 96 (p < 0.05) significantly regulated proteins of which n = 54 were tumour-specific. To unravel molecular circuits linked to aberrant EGFR signalling diverse computational approaches were employed and this defined n = 7 key nodes using n = 82 disease regulated proteins for network construction. STRING analysis revealed protein-protein interactions of > 70% disease regulated proteins with individual proteins being validated by immunohistochemistry. The disease regulated network proteins were mapped to distinct pathways and bioinformatics provided novel insight into molecular circuits associated with significant changes in either glycolysis and gluconeogenesis, argine and proline metabolism, protein processing in endoplasmic reticulum, Hif- and MAPK signalling, lipoprotein metabolism, platelet activation and hemostatic control as a result of aberrant EGF signalling. The biological significance of the findings was corroborated with gene expression data derived from tumour tissues to evntually define a rationale by which tumours embark on intriguing changes in metabolism that is of utility for an understanding of tumour growth. Moreover, among the EGF tumour specific proteins n = 11 were likewise uniquely expressed in human HCC and for n = 49 proteins regulation in human HCC was confirmed using the publically available Human Protein Atlas depository, therefore demonstrating clinical significance.

Conclusion

Novel insight into the molecular pathogenesis of EGF induced liver cancer was obtained and among the 37 newly identified proteins several are likely candidates for the development of molecularly targeted therapies and include the nucleoside diphosphate kinase A, bifunctional ATP-dependent dihydroyacetone kinase and phosphatidylethanolamine-binding protein1, the latter being an inhibitor of the Raf-1 kinase.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1312-z) contains supplementary material, which is available to authorized users.

Plasmid transfer of plasminogen K1-5 reduces subcutaneous hepatoma growth by affecting inflammatory factors

There is evidence that plasminogen K1-5 (PlgK1-5) directly affects tumour cells and inflammation. Therefore, we analysed if PlgK1-5 has immediate effects on hepatoma cells and inflammatory factors in vitro and in vivo. In vitro, effects of plasmid encoding PlgK1-5 (pK1-5) on Hepa129, Hepa1-6, and HuH7 cell viability, apoptosis, and proliferation as well as VEGF and TNF-alpha expression and STAT3-phosphorylation were investigated. In vivo, tumour growth, proliferation, vessel density, and effects on vascular endothelial growth factor (VEGF) and tumour necrosis factor alpha (TNF-alpha) expression were examined following treatment with pK1-5. In vivo, pK1-5 halved cell viability; cell death was increased by up to 15% compared to the corresponding controls. Proliferation was not affected. VEGF, TNF-alpha, and STAT3-phosphorylation were affected following treatment with pK1-5. In vivo, ten days after treatment initiation, pK1-5 reduced subcutaneous tumour growth by 32% and mitosis by up to 77% compared to the controls. Vessel density was reduced by 50%. TNF-alpha levels in tumour and liver tissue were increased, whereas VEGF levels in tumours and livers were reduced after pK1-5 treatment. Taken together, plasmid gene transfer of PlgK1-5 inhibits hepatoma (cell) growth not only by reducing vessel density but also by inducing apoptosis, inhibiting proliferation, and triggering inflammation.

Serum levels of angiogenic and anti-angiogenic factors: their prognostic relevance in locally advanced hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prototype tumor wherein angiogenesis plays a vital role in its progression. The role of VEGF, a major angiogenic factor in HCC is known; however, the role of anti-angiogenic factors simultaneously with the angiogenic factors has not been studied before. Hence, in this study, the serum levels of major angiogenic [Vascular Endothelial Growth Factor (VEGF), angiopoietin-2 (Ang-2)] and anti-angiogenic (endostatin, angiostatin) factors were analyzed and correlated with clinico-radiological features and with outcome. A total of 150 patients (50 HCC, 50 cirrhosis and 50 chronic hepatitis) and 50 healthy controls were enrolled in this study. Serum levels of VEGF, Ang-2, endostatin, and angiostatin were estimated by enzyme-linked immunosorbent assay. HCC shows significantly elevated serum levels of angiogenic factors VEGF and Ang-2 and of anti-angiogenic factors endostatin and angiostatin. ROC curve analysis for serum VEGF yielded an optimal cut-off value of 225.14 pg/ml, with a sensitivity of 78 % and specificity of 84.7 % for a diagnosis of HCC and its distinction from other group. Using this value, the univariate and multivariate analysis revealed significantly poor outcome in patients with higher levels of serum VEGF (p = 0.009). Combinatorial analysis revealed that patients with higher levels of both angiogenic and anti-angiogenic factors showed poor outcome. Serum VEGF correlates with poor survival of HCC patients and, therefore, serves as a non-invasive biomarker of poor prognosis. Moreover, elevated levels of anti-angiogenic factors occur endogenously in HCC patients.

Anti-tumoural effects of PlgK1-5 are directly linked to reduced ICAM expression, resulting in hepatoma cell apoptosis

PURPOSE

Angiostatin and angiostatin-like molecules are known as anti-angiogenic factors, which inhibit endothelial cell functions resulting in reduced tumour growth. Recent data indicate that these molecules, especially PlgK1-5, directly affect tumour cells, which could explain the strong anti-tumoural effects of PlgK1-5. Therefore, we have analysed whether PlgK1-5 alters tumour cell functions and expression levels of cell adhesion molecules in murine and human hepatoma cells in vitro and in vivo.

METHODS

First, effects on tumour growth, proliferation and apoptosis were investigated in vivo in a subcutaneous tumour model. In vitro, effects of PlgK1-5 on tumour cell apoptosis, clonal expansion, migration, corresponding ICAM expression and intracellular signal transduction in murine Hepa129 and human HuH7 hepatoma cells have been analysed.

RESULTS

In vivo, subcutaneous tumour growth was reduced by 75% in PlgK1-5-treated animals compared to the controls. This was accompanied by increased tumour cell apoptosis (up to 33%) and decreased tumour cell proliferation (by up to 21%). In vitro, PlgK1-5 induced apoptosis in hepatoma cells, corresponding to increased caspase-8 cleavage and reduced AKT phosphorylation. Migration and clonal expansion was also diminished in PlgK1-5-treated Hepa129, corresponding to decreased ICAM expression levels.

CONCLUSIONS

Here, we show that PlgK1-5 directly affects tumour cells by decreasing cell adhesion resulting-at least partly-in apoptosis. This is mediated by altered intracellular signal transduction and by activation of the caspase cascade. These findings further underscore the potential therapeutic role of PlgK1-5 in the treatment of HCC.

Evaluation of the antiangiogenic effect of Kringle 1-5 in a rat glioma model

BACKGROUND

Kringle 1-5 (K1-5) is a potent antiangiogenesis factor for treating breast cancer and hepatocellular carcinoma. However, its use in treating brain tumors has not been studied.

OBJECTIVE

To evaluate whether K1-5 is effective at treating gliomas.

METHODS

The effects of K1-5 on cell morphology and cytotoxicity with or without lipopolysaccharide were tested in primary mixed neuronal-glial cultures. The antiglioma activity of K1-5 was evaluated by intra-arterial administration of K1-5 at 4 days after implantation of C6 glioma cells into the rat hippocampus. In 1 group of animals, tumor size, tumor vasculature, and tumor histology were evaluated on day 12. Animal survival was assessed in the other group.

RESULTS

In vitro studies showed that K1-5 did not induce cytotoxicity in neurons and glia. In vivo studies demonstrated that K1-5 reduced vessel length and vessel density and inhibited perivascular tumor invasion. In addition, K1-5 normalized vessel morphology, decreased expression of hypoxia-inducible factor-1α and vascular endothelial growth factor, decreased tumor hypoxia, and decreased pseudopalisading necrosis. The average tumor volume was smaller in the treated than in the untreated group. Furthermore, animals treated with K1-5 survived significantly longer.

CONCLUSION

Kringle 1-5 effectively reduces the growth of malignant gliomas in the rat. Although still far from translation in humans, K1-5 might be a possible future alternative treatment option for patients with gliomas.

Hepatocellular carcinoma: insight from animal models

Hepatocellular carcinoma (HCC) ranks as the third most common cause of death from cancer worldwide. Although major risk factors for the development of HCC have been defined, many aspects of the evolution of hepatocellular carcinogenesis and metastasis are still unknown. Suitable animal models are, therefore, essential to promote our understanding of the molecular, cellular and pathophysiological mechanisms of HCC and for the development of new therapeutic strategies. This Review provides an overview of animal models that are relevant to HCC development, metastasis and treatment. For HCC development, this Review focuses on transgenic mouse models of HBV and HCV infection, which provide experimental evidence that viral genes could initiate or promote liver carcinogenesis. Animal models of HCC metastasis provide platforms to elucidate the mechanisms of HCC metastasis, to study the interaction between the microenvironment and HCC invasion and to conduct intervention studies. In addition, animal models have been developed to investigate the effects of new treatment modalities. The criteria for establishing ideal HCC animal models are also discussed.

Plasminogen fragment K1-3 inhibits expression of adhesion molecules and experimental HCC recurrence in the liver

PURPOSE

There is no established adjuvant or neo-adjuvant treatment to curb tumor recurrence of hepatocellular carcinoma (HCC). Recent data showed that angiostatic factors can inhibit tumor cell adhesion to the endothelium and therefore recurrence/metastasis. We tested a potential preventive, pre-operative strategy using plasminogen kringles 1-3 (K1-3) to overcome this hurdle.

MATERIALS AND METHODS

Effects of K1-3 on the intercellular cell adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM) expression was analyzed in vitro and in vivo on RNA and protein levels. Influence of K1-3 on HCC recurrence in the liver was analyzed in an orthotopic tumor model.

RESULTS

K1-3 decreased ICAM expression in Hepa129 tumor cells and VCAM expression in SVEC4-10 endothelial cells in vitro. In vivo, ICAM was reduced in histological tumor sections. Preventive treatment with AdK1-3 inhibited experimental HCC recurrence and tumor growth in the liver.

CONCLUSIONS

We were able to show that K1-3 inhibits intrahepatic tumor recurrence. This novel aspect elucidates a possible approach to prevent HCC recurrence.

siRNA targeting VEGF inhibits hepatocellular carcinoma growth and tumor angiogenesis in vivo

BACKGROUND/AIMS

We have investigated whether siRNA targeted against VEGF inhibits functional properties of endothelial cells in vitro and HCC tumor growth and blood vessel formation in vivo.

METHODS

The influence of siRNA-VEGF on endothelial cell proliferation, apoptosis and tube formation were analyzed in vitro. Antitumoral effects were examined in an orthotopic tumor model after ex vivo transfer or intraperitoneal treatment of siRNA, respectively. Intratumoral microvessel density was assessed by CD31 staining.

RESULTS

VEGF expression was inhibited in Hepa129 by 70% and in SVEC4-10 by 48% within two days after transfection. In vitro, endothelial cell proliferation and tube formation was reduced by 23% and 38%, respectively. Interference with VEGF signaling was demonstrated by reduced pAKT in hepatoma cells. Tumor growth was inhibited by ex vivo transfer or intraperitoneal application of siRNA-VEGF by 83% or 63% in orthotopic tumors within 14 days. VEGF protein was reduced in both models by 29% and 44%. Microvessel density dropped to 34% for tumors from ex vivo transfected cells and 39% for systemic treated tumors.

CONCLUSIONS

The results show that VEGF knockdown can be associated with reduced endothelial cell proliferation and tube formation in vitro and decreased tumor growth and microvessel density in vivo.

Accelerated orthotopic hepatocellular carcinomas growth is linked to increased expression of pro-angiogenic and prometastatic factors in murine liver fibrosis

BACKGROUND

Most experimental therapy studies are performed in mice that bear subcutaneous or orthotopic hepatoma but are otherwise healthy. We questioned whether a pre-existing fibrosis affects tumour development of implanted syngenic hepatoma cells. To further investigate a selected panel of factors involved in tumour growth, tumour organ samples were characterized for gene expression of vascular endothelial growth factor (VEGF)-A/-C, VEGF receptors Flt1, Flk-1, Flt-4 and for VEGF-A protein levels.

RESULTS

The presented data show that tumour sizes were 3.7-fold increased and fibrotic livers had numerous satellites. Increased tumour sizes were associated with elevated intratumoral VEGF-A protein amounts and intratumoral increased VEGF receptor gene expression levels in tumour tissue from fibrotic livers as compared with non-fibrotic livers. Additionally, intratumoral gene expression levels of matrix metalloproteinase-2 (MMP-2) and MMP-9 were elevated in fibrotic mice.

CONCLUSION

Our results indicate that liver fibrosis stimulates tumour development of implanted syngenic hepatoma cells. Accelerated tumour growth was going along with elevated intratumoral VEGF-A and VEGF-A receptor status, which most probably mediated pro-angiogenic and prometastatic effects in this model. Furthermore, advanced tumour spread was associated with increased MMP-2/-9 expression. These data suggest that the intratumoral VEGF-A proteins levels and VEGF receptor status contribute to accelerated hepatocellular carcinoma development in fibrotic mice and that elevated MMP-2, MMP-9 and VEGF-C levels could promote tumour metastasis in this model.