Correlation Study Of Astragalus Polysaccharide On Signal Transduction Mediated By P53Gene And Gastric Cancer Development

P53is an important antioncogene,and it had been showed that,there were more than50%mutations of P53gene happened in human tumors. Currently, the mutations of P53gene had been considered as the most common genetic changes in tumors,so it means the change of P53gene maybe the main risk factor of human tumors.The cell signal transduction pathway mediated by P53gene had played an important role in regulating cell activity,but the relationship between this pathway and the others were complicated.In this experiment, SGC-7901,a kind of human gastric cancer cells,were vaccinated into nude,and had a therapy by APS, observated the effect of APS on weight,volume, inhibition rate of nude vaccinated with SGC-7901;detected the result of expression of P53downstream Bcl2/Bax, Fas/FasL and PTEN、NF-κB、CDX2genes,found out the relationship between signal transduction mediated by P53gene of APS and the development of gastric cancer.At the end of experiment, SGC-7901were cultured in vitro to observe the effecte of APS on cell proliferation,cell cycle and cell apoptosis in gastric cancer cells.Part1Effect of APS on nude vaccinated with SGC-7901Section1.The culture and collection of SGC-7901Subculture was carried on by Human Gastric Carcinoma Cell Line SGC-7901in RPMI1640culture solution. SGC-7901cells in logarithmic growth phase were chosen to make into single cell suspensions, regulated cell concentration to1.0×108/ml through Trypan blue staining.The animal models were established by vaccinating single cell suspensions of SGC-7901into nude.Section2. Effect of APS on weight,volume, inhibition rate of nude vaccinated with SGC-7901The nude models were divided into model group,APS high group,APS low group and5-FU group.The weight of nude and the volume of tumor tissue were measured on the0,7th,14th,21th,28th day.At the end of the experiment,the nude were killed to remove tumor tissue, measure it and calculate inhibition rate.The result showed that the weight of models increased obviouly, given intervention of APS,there were no significant difference,weight of5-FU group decreased significantly.The volume and weight of tumor block in model increased obviouly,and the others grew slowly, the volume and weight of tumor block in other group decreased significantly. Pathological examination showed diffuse growth of tumor cells in model group, tumor cell heterogeneity size, form a distinct nodules, large stain nuclear, nuclear atypia, scattered tumor cells degeneration and necrosis, after APS intervention, the tumor nodules volume reduced, showing a small amount of necrotic nodules, the remnants of the tumor cells decreased, and the experimental group had significantly improved.On summary, we could obviously find that APS can inhibit tumor growth of human gastric cancer cell SGC-7901, it had a therapeutic effect to tumor tissue.Section3.Effect of APS on expression of P53downstream gene in tumor tissue.The expression of Bcl2Bax、Fas/Fasl and PTEN、NF-κB、CDX2in tumor tissue were observe by immunohistochemistry.To study the inhibit effect and mechanism of APS on tumor vaccinated with SGC-7901.The result showed that APS could obviously inhibit the tumor through downing Bcl2/Bax and increasing Fas/Fasl.And then APS could increase the expression of PTEN,CDX2and down expression of NF-κB (p65). Tips:APS can induce apoptosis in gastric cancer.Part2Effect of APS on cell proliferation and cell cycle in gastric cancer cellsSubculture was carried on by Human Gastric Carcinoma Cell Line SGC-7901in RPMI1640culture solution. MTT assay was used to determine the inhibitory effect of Astragalus Polysaccharides on the growth of SGC-7901cells. The changes of cell cycle and cell apoptosis of SGC-7901were detected by flow cytometry. MTT assay show that Astragalus Polysaccharides could inhibit the proliferation of cell line SGC-7901,cell cycle analysis indicated that Astragalus Polysaccharides can arrest SGC-7901at S phase.Astragalus Polysaccharides can inhibit proliferation of gastric carcinoma cells,and it can arrest cell cycle of S phase and promote apoptosis may be one of the mechanisms.