Gastric Cancer Gene Expression Profiles And Mechanism Of The Procyanidins Cancer Chemoprevention Studies

This thesis includes two parts:The gene expression of initiation and progression of gastric cancer was investigated in part one. The latest Cancer chemoprevention of procyanidins from grapes seeds was systematically studied in part two.PART ONETo understand the molecular pathophysiology of cancer initiation and progression . We studied novel gene expression by cDNA microarray method. The PCR products of 2000 genes were spotted onto a kind of Chemical-material-coated-glass slide in array. Three the mRNAs from the normal rats and initiation or progression of gastric cancer rats were reversibly transcribed to cDNAs with the incorporation of fluorescent條abeled mRNA from normal rats by direct incorporation of Cy3-conjugated dUTP and labeled mRNA from initiation or progression gastric cancer rats with Cy5. After hybridization, Biodoor20s cDNA microarray were scanned for the fluorescent intensity. Gene expression of gastric cancer in initiation or progression was6screened through the analysis of difference in gene profile. Among 2000 target genes, there were 40 genes of initiation cancer rats whose expression level differed from normal tissure 33 out of 40 genes showed down regulation and 7 out of 40 genes expression tip regulation. When progression of gastric cancer, there were 82 genes which expression level differed from normal. 26 out of 40 genes showed down regulated, 56 out of 82 genes showed up regulated. It was suggested that further analysis of these differentially expressed initiation and progression of gastric cancer associated genes will be helpful for understanding the molecular mechanism of Gastric cancer.Part twoI .Antioxidation of procyanidins from grapes seedsprocyanidins could inhibit PMNs releasing H202 induced by croton oil.Procyanidins serum of rats also had the same effect, appeared dose dependent. Inhibitory effect of procyanidins on hepatic mitochondria lipid peroxidation induced by croton oil was observed. Procyanidins could raise7the activity of SOD and decrease the level of MIDA. In vivo animal experiment showed that procyanidins had the inhibitory effect on mice ear edema induced by croton oil.2.Effect of Pr骳yanidins on Carcinogen-induced DNA Damage (DNA Synthesis)Using labeled [3H]thymidine ([3H]-TdR) uptake assay, the protective effect of procyanidins on DNA damage of L929 cellsinduced by MNNG was investigated according to the content of [3H]TdR uptake into DNA of cells. It was showed that different doses of MINING can induce severe DNA damage of L929 cell lines, otherwise co-incubated with Procyanidins can alleviate the damage. Hydroxyl radical (HO ), a product of Fenton and l-Jberwesis reaction, can attack DNA large fragments and lead to DNA cleavage. Fixed cells in Lower Melting Agarose Gel and coated slides, broken cell membrane by basic salt solution, then DNA was despiralized by alkaline. Put the slides in driving solution, the DNA fragments shift to positive pole under the magnetic field. The more DNA fragments caused by severe damage, the faster of electrophoresis mobility. Intact DNA large8fragments were blocked and sticked on the initial band. After EB staining, detected by their fluorescence, the damaged DNA ladder represents comet-like images and allows to quantitative or qualitative analysis by electropherogram photographing. The more severe DNA damage, the ladder was less sharp with heavy tail. It was showed that Procyanidins could reduce the DNA damage induced by MNNG in L929 cells.Procyanidins is a mixture of several amounts of Catechin and Epicatechin and dimer of Catechin and Epicatechin. Procyanidins can react with nitrosamines and block the carcinogenesis of MNNG. MNNG can form free radicals in the body, while flavane-3,4-diol, one of the chemicals in the procyanidins can capture superoxide ion and hydroxyl radical (HO ), so procyanidins can serve as an antagonist against MNNG-induced DNA damage, and show certain dose dependent effect relationship.3.Effect of...