Scutellaria Barbata Extract Inhibits Vegf Expression Enhanced Anti-tumor Immune Preliminary Study

Angiogenesis is regarded necessary for growth and metastasis in all solid tumors, moreover, it may be correlated with invasive growth of solid tumors. Angiogenesis is regulated by certain stimulators and inhibitors. Vascular endothelial growth factor (VEGF) is the most typical angiogenesis stimulator, overexpressing in many tumors. Now anti-VEGF therapy has brought great achievements and become the focus of cancer research. Dendritic cells are regarded as the most potent professional antigen-presenting cells with a unique ability to induce and sustain primary immune responses, and plan a central role in antitumor immunity. Recent studies showed that VEGF can also dramatically inhibit the differentiation and maturity of DCs, and reduce the number of them, which lead to tumor evasion from immune system surveillance.Our former experiments showed that the extractive of scutellariae barbatae can inhibit tumor angiogenesis in vitro through the inhibition of VEGF. On the basis of the outcome, we extract the effective components from the of scutellariae barbatae, conduct qualitative and quantitative analysis of them; then we establish the model of mice bearing S180 tumor to observe the inhibitory effect of scutellariae barbatae extractive on tumor growth and its acting target, investigate the influence of scutellariae barbatae extractive on the expression of VEGF and the infiltration of DCs by immunohistochemical method. The main result and conclusion showed as below:1. Extraction, qualitative and quantitative analysis of scutellariae barbatae: systematic solvent separation is employed to extract scutellariae barbatae effective components. We find that scutellariae barbatae extractive is mostly flavonoids through color reaction. According to the method in China Pharmacopeia (2005 edition), we regard Scutellarin as contrast calibre, and determine the content of flavonoids in scutellariae barbatae extractive by spectrophotometry at the wave length 335nm. The results show that the average content of flavonoids is 23.842%.2. The influence of scutellariae barbatae extractive on mice bearing S180 tumor: Tumor growth was suppressed beyond 40% in high-dosage group of scutellariae barbatae extractive and scutellariae barbatae injection group, and their inhibition rares have statistical difference when compared to control group. Middle-dosage group and low- dosage group of scutellariae barbatae extractive don't have statistical significance, but the three groups have good linear relationship, implying that Scutellariae barbatae extractive can dose dependently inhibit the growth of tumor. The spleen index of treatment groups don't have statistical significance, but the three groups of Scutellariae barbatae extractive also have linear relationship, we infer that Scutellariae barbatae extractive can enhance the immune power of airframe, and the outcome which doesn't have statistical significance is due to underdose and lower purity.3. The influence of scutellariae barbatae extractive on the expression of VEGF and the infiltration of DCs: With the increase of the concentration of scutellariae barbatae extractive, the expression of VEGF is gradually reduced. Middle-dosage group and high-dosage group of scutellariae barbatae extractive have statistical significance, and the inhibition degree is greater than endostatin group and ginsenoside rg3 group. The control group doesn't have the infiltration of DCs, while treatment groups have the infiltration of DCs to a certain degree. The infiltration density of DCs in middle-dosage group and high-dosage group of scutellariae barbatae extractive are remarkable, and the two groups have statistical significance. We make a correlation analysis of the expression of VEGF and infiltration of DCs, the data shows that they have significant negative correlation.Conclusion: Scutellariae barbatae extractive can dose dependently inhibit the growth of tumor, and moreover, they enhance the immune power of airframe to some extent. The mechanism is probably that scutellariae barbatae extractive inhibit the expression of VEGF in tumor, and thereby inhibit tumor angiogenesis; on the other side they relieve inhibitory effect on DC mediated by VEGF, improve antitumor immunity, reaching obvious suppression of tumor growth.