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

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.

Clinical significance of circulating sICAM-1 and GPC-3 mRNA expression in the diagnosis and prognostic evaluation of hepatocellular carcinoma

AIM: To quantitatively detect the levels of circulating soluble intercellular adhesion molecule-1 (sICAM-1) and glypican-3 (GPC-3) mRNA expression in peripheral blood mononuclear cells (PBMCs) in patients with liver diseases for exploring their significance in the diagnosis and prognostic evaluation for hepatocellular carcinoma (HCC).

METHODS: Total RNA was extracted from circulating PBMCs collected from patients with liver diseases. GPC-3 cDNA was synthetized by reverse transcription and amplified by fluorescent quantitative PCR. The levels of circulating ICAM-1 were quantitatively detected by enzyme-linked immunosorbent assay.

RESULTS: The levels of sICAM-1 were increasing during the development of liver diseases, significantly higher in HCC patients than in those with liver cirrhosis (t = 3.184, P = 0.002) or chronic hepatitis (t = 3.962, P < 0.001). sICAM-1 levels were significantly associated with periportal cancerous embolus (t = 2.941, P = 0.005) and extrahepatic metastasis (t = 3.282, P = 0.002), but not with patients' age, sex, AFP level, HBsAg positivity, or tumor size. The positive expression of GPC-3 mRNA in PBMCs was found only in HCC patients (70.9%, 39 of 55), and not in patients with liver cirrhosis, chronic hepatitis, metastatic liver cancer, non-liver tumors, or normal controls (χ² = 26.773, P < 0.001). The expression of GPC-3mRNA in PBMCs was associated with HBV infection (χ² = 14.601, P < 0.001), TNM stage (χ² = 17.732, P < 0.001), periportal cancerous embolus, and extrahepatic metastasis (χ² = 22.271, P < 0.001), and not with tumor size, tumor number, AFP level or differentiation degree. Combined detection of GPC-3 mRNA and serum AFP level could improve the detection rate of HCC.

CONCLUSION: Detection of circulating sICAM-1 and GPC-3 mRNA in PBMCs could be used for the diagnosis and metastasis monitoring of HCC, especially in AFP-negative patients with HCC.

Effects of pegylated interferon α2b on metastasis of hepatocellular carcinoma

OBJECTIVE

Interferon (IFN) has an anti-tumor activity in hepatocellular carcinoma (HCC) via anti-angiogenesis and induction of apoptosis. We have previously reported anti-metastatic effects of IFN combined chemotherapy on the outcome of HCC patients. The aim of this study was to investigate anti-metastatic effects of IFN.

METHODS

In vitro, pegylated interferon α2b (PEG-IFN-α2b) was administered to mouse MH134 cells (mouse HCC cell line, MH134), and anti-implantation effects were examined by evaluating the inhibition of cell invasion and cell proliferation. Expressions of vascular endothelial growth factor (VEGF) mRNA were also measured. In vivo, PEG-IFN-α2b was subcutaneously administered into MH134 cells and tumor growth was evaluated. In distant metastasis models, PEG-IFN-α2b was subcutaneously administered and MH134 cells were injected into the spleen. The number of liver metastases and microvessel densities (MVD) were counted.

RESULTS

In vitro, the proliferation of MH134 cells was significantly suppressed by PEG-IFN-α2b dose-dependently. MH134 cells added with PEG-IFN-α2b exhibited significantly lower levels of invasion potential. In vivo, tumor size in mice treated with PEG-IFN-α2b significantly suppressed compared with control mice (mean 0.5 versus 5.0 cm, in diameter, P < 0.05) and also decreased number of liver metastases (19.3 versus 6.0, P < 0.05). Moreover, PEG-IFN-α2b significantly suppressed angiogenesis compared with the control.

CONCLUSION

PEG-IFN-α2b in itself had remarkable anti-metastatic effects via inhibition of angiogenesis and cell adhesions.

Human plasminogen kringle 1-5 reduces atherosclerosis and neointima formation in mice by suppressing the inflammatory signaling pathway

BACKGROUND

Activation of vascular endothelial cells plays an important role in atherogenesis and plaque instability. Recent research has demonstrated that late-stage inhibition of plaque angiogenesis by angiostatin (kringle 1-4) reduces macrophage accumulation and slows the progression of advanced atherosclerosis. Kringle 1-5 (K(1-5)) is a variant of angiostatin that contains the first five kringle domains of plasminogen.

OBJECTIVE

To investigate whether K(1-5) has an inhibitory effect on early-stage atherosclerosis, using the apolipoprotein E (ApoE)-deficient mouse model and a carotid artery ligation model.

METHODS

ApoE-deficient mice received K(1-5) treatment for 4 weeks, and the severity of aortic atherosclerosis was measured. In the ligation model, the left common carotid arteries of C57BL/6 mice were ligated near the carotid bifurcation, and the mice received K(1-5) for 4 weeks. Human umbilical vein endothelial cells were pretreated with K(1-5) before tumor necrosis factor-alpha (TNF-alpha) treatment to explore the anti-inflammatory effect of K(1-5).

RESULTS

The areas of the lesion in the aortas of ApoE-deficient mice that received K(1-5) treatment were notably decreased, and the formation of carotid neointima in the C57BL/6 mice was decreased by treatment with K(1-5). Expression of TNF-alpha-induced intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 was inhibited by K(1-5) treatment, possibly via downregulation of translocation of nuclear factor-kappaB and expression of reactive oxygen species.

CONCLUSIONS

K(1-5) reduced atherosclerosis and neointima formation in mice, possibly through inhibition of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 expression in endothelial cells.