The vascular endothelial growth factor (VEGF) receptor-2 is a major regulator of VEGF-mediated salvage effect in murine acute hepatic failure

Functional convergence of Akt protein with VEGFR-1 in human endothelial progenitor cells exposed to sera from patient with type 2 diabetes mellitus

Diabetes mellitus type 2 predisposes patients to various microvascular complications. In the current experiment, the potent role of diabetes mellitus was investigated on the content of VEGFR-1, -2, Tie-1 and -2, and Akt in human endothelial progenitor cells. The gene expression profile of mTOR and Hedgehog signaling pathways were measured by PCR array. The possible crosstalk between RTKs, mTOR and Hedgehog signaling was also studied by bioinformatic analysis. Endothelial progenitor cells were incubated with serum from normal and diabetic for 7days. Compared to non-treated cells, diabetic serum-induced cell apoptosis (~2-fold) and prohibited cell migration toward bFGF (p<0.001). ELISA analysis showed that diabetes exposed cells had increased abundance of Tie-1, -2 and VEGFR-2 and reduced amount of VEGFR-1 (p<0.0001) in diabetic cells. Western blotting showed a marked reduction in the protein level of Akt after cells exposure to serum from diabetic subjects (p<0.0001). PCR array revealed a significant stimulation of both mTOR and Hedgehog signaling pathways in diabetic cells (p<0.05). According to data from bioinformatic datasets, we showed VEGFR-1, -2 and Tie-2, but not Tie-1, are master regulators of angiogenesis. There is a crosstalk between RTKs and mTOR signaling by involving P62, GABARAPL1, and HTT genes. It seems that physical interaction and co-expression of Akt decreased the level of VEGFR-1 in diabetic cells. Regarding data from the present experiment, diabetic serum contributed to uncontrolled induction of both mTOR and Hedgehog signaling in endothelial progenitor cells. Diabetes mellitus induces mTOR pathway by involving receptor tyrosine kinases while Hedgehog stimulation is independent of these receptors.

Update on implications and mechanisms of angiogenesis in liver fibrosis

Liver fibrosis occurs as a compensatory response to the process of tissue repair in a wide range of chronic liver injures. It is characterized by excessive deposition of extracellular matrix in liver tissues. As the pathogenesis progresses without effective management, it will lead to formation of liver fiber nodules and disruption of normal liver structure and function, finally culminating in cirrhosis and hepatocellular carcinoma. A new discovery shows that liver angiogenesis is strictly associated with, and may even favor fibrogenic progression of chronic liver diseases. Recent basic and clinical investigations also demonstrate that liver fibrogenesis is accompanied by pathological angiogenesis and sinusoidal remodeling, which critically determine the pathogenesis and prognosis of liver fibrosis. Inhibition of pathological angiogenesis is considered to be a new strategy for the treatment of liver fibrosis. This review summarizes current knowledge on the process of angiogenesis, the relationships between angiogenesis and liver fibrosis, and on the molecular mechanisms of liver angiogenesis. On the other hand, it also presents the different strategies that have been used in experimental models to counteract excessive angiogenesis and the role of angiogenesis in the prevention and treatment of liver fibrosis.

Targeted therapies in metastatic esophageal cancer: advances over the past decade

Esophageal cancer is one of the most aggressive malignancies of the upper aerodigestive tract. Despite advances in surgical techniques and multi-modality therapies, the 5-year survival rate remains poor (14%). Over the past decade, efforts have been focused on the field of drug development with the advancement of novel molecularly targeted therapeutic agents. These agents target a variety of cancer relevant pathways such as vascular endothelial growth factor (VEGF) or its receptor, the cyclooxygenase-2 (COX-2), epidermal growth factor receptor (EGFR), and mammalian target of rapamycin (mTOR) pathways. The number of approved targeted agents remains few, with HER-2 inhibitors leading the list for treatment of HER-2 expressing metastatic adenocarcinomas. Novel agents have not yet been widely explored in esophageal cancer. In this review, we will provide a concise and systematic overview of the development of novel targeted therapies currently under investigation for the treatment of metastatic esophageal disease.

Significance of the vascular endothelial growth factor and the macrophage migration inhibitory factor in the progression of hepatocellular carcinoma

The aim of the present study was to investigate the expression of vascular endothelial growth factor (VEGF) and macrophage migration inhibitory factor (MIF) in HCC progression and their correlation with clinicopathological factors as well as the relationship between their expression levels. The expression of serum VEGF and MIF was evaluated in 150 patients with HCC and in 30 normal volunteers by enzyme-linked immunosorbent assay (ELISA). VEGF and MIF expression levels were evaluated by immunohistochemistry on tissue microarrays containing 150 HCCs with paired adjacent non-cancer liver tissues. VEGF and MIF mRNA levels were determined by quantitative PCR in another 48 HCCs. The correlation of VEGF and MIF with clinicopathological factors was analyzed in HCC. Serum VEGF and MIF concentrations were higher in HCC patients than the levels in the controls. The expression levels of VEGF and MIF in the HCC tissues were both higher than those in the adjacent non-tumor liver tissues. Overexpression of VEGF and MIF was significantly associated with tumor size (P=0.027 and 0.022, respectively), intrahepatic metastasis (P=0.032 and 0.027, respectively), vascular invasion (P=0.044 and 0.039, respectively) and TNM stage (P=0.028 and 0.013, respectively). Furthermore, VEGF and MIF mRNA levels were higher in HCC compared to levels in the paired non-cancer liver tissues. VEGF and MIF mRNA levels were correlated with tumor stage and metastasis. The expression of VEGF was positively related with MIF expression in HCC. The expression of MIF and VEGF in HCC was markedly positively correlated, which suggests that MIF and VEGF play an important role in the progression of HCC. Both factors may concomitantly accelerate the progression of HCC.

Salvianic acid A inhibits lipopolysaccharide-induced apoptosis through regulating glutathione peroxidase activity and malondialdehyde level in vascular endothelial cells

AIM

To find out the role of salvianic acid A (SAA) in the protection of vascular endothelial cells (VEC) and its possible mechanism in vitro.

METHODS

The ingredient at various concentrations was added to human umbilical vein endothelial cells (HUVEC) treated with 0.5 μmol·L(-1) lipopolysaccharide (LPS) for 24 h. Apoptotic morphological changes of cells were observed under inverted phase contrast microscope; the cell viability was quantified using MTT assay. Nuclear fragmentation of cells was observed under laser scanning confocal microcope after being stained with acridinorange. Cell cycle distribution was detected by flow-cytometry after being stained with propidium iodide (PI). The activities of glutathione peroxidase (GPH-PX) as well as maleic dialdehyde (MDA) level in cells were measured by spectrophotometric methods as described in the assay kits.

RESULTS

Apoptotic morphological changes and the decrease of cell viability of these cells were obviously inhibited by SAA in a dose-dependent manner. Furthermore, the abnormal cell cycle distribution, the decrease of GSH-Px activity and the increase of MDA level induced by LPS were markedly reversed.

CONCLUSION

SAA exerts protective effect on VEC induced by LPS via an antioxidative mechanism.