Study On Antitumor Effects In Vivo And Mechanism Of Icariside

Epimedium brevicornu Maxim.is a traditional Chinese medicine with multipul bioactivities,its main active ingredient is Epimedium flavanone,which has significant pharmacological activity,such as Zhuang Yang,treating bone shortening,delaying senescence,improving the immune function of the body and inhibiting the growth of tumor.Its effective component has high potential as drug development.In fact,the immunotherapy is a novel anti-tumor strategy which has attracted much attention.In recent years,studies on their anti-tumor effects revealed that one of the major components,the flavonoids,can stimulate passive immunity of organism,and activate the body’s own immune system to kill tumor cells.At present,the clinical drugs for immunotherapy are mainly bio-macromolecules,such as antibodies.However,protein and peptide drugs have their limitation due to the poor stability,high costs,and allergic reations.Thus,finding novel chemical entities for immunotherapy has profound significance.IcarisideⅡis one of the flavonoids in Epimedium brevicornu Maxim.From the previous studies,icarisideⅡshowed activity on stimulating the production of IFN-γin T lymphoma cells.While icariin and other components in Epimedium brevicornu Maxim.could not show this activity.Moreover,the icarisideⅡhas only one more rhamnose base compared with the molecular structure of icaritin which is the new anti hepatoma drug that has already entered the three phase of clinical trials,and the water solubility of icarisideⅡis better and the bioavailability is higher.In this study,the anti-tumor activity and mechanism of icarisideⅡwere further studied in vivo and in vitro.The main contents of this paper include the following four parts:1.The antitumor activity of icarisideⅡin C57BL/6J tumor bearing mice.The results of the study show that LD₅₀ value of icarisideⅡis greater than 2000 mg/kg,which indicates a relative high safety.The results in the antitumor experiments showed that icarisideⅡin S180and H22 mice showed obvious tumor inhibiting effect.Increase on the production of IFN-γin these mice were also observed.Besides,icarisideⅡcould improve the thymus and spleen weight index,which means an improvement of the immune function in these tumor-bearing mice.2.Evaluation of the activity of icarisideⅡat the cell level.Firstly,CCK8 method was used to study the inhibitory effect of icarisideⅡon hepatoma cell proliferation by CD3⁺T cells.The results showed that icarisideⅡcould significantly inhibit the proliferation of hepatoma cells.Further,the secretion of IFN-γfrom T cells were evaluated by the ELISA assay.The results showed that icarisideⅡcould significantly promote the secretion of IFN-γin T cells.3.The effect of icarisideⅡon tumor cells proliferation and related signaling pathways were studied using Western blot,CCK8,flow cytometry analysis.The results showed that the low concentration of icarisideⅡcould promote the IFN-γsecretion in T cells.Furthermore,these IFN-γbind with the IFN-γreceptor on the cell surface to activate the JAK1/STA1 pathway,which increased the expression level of key proteins Noxa,Cytochrome C,cleaved PARP,cleaved Caspase 3 and cleaved Caspase 9 in IFN-γmediated apoptosis pathway and inhibited the expression of antioxidant protein HO-1.Also,icarisideⅡincreased the accumulation of ROS in the cells and lead to the loss of mitochondrial membrane potential,which eventually leads to the death of the hepatoma cells.The above research on the anti-tumor activity and mechanism of icarisideⅡin vivo has explored the development of a new natural small molecule anticancer drug and provided a basis for clinical research of Epimedium brevicornu Maxim.and its main active components in tumor immunotherapy.