| Lung cancer is the number one cancer killer in the world,and its recovery rate is relatively low. Lung cancer is the first leading cause of cancer-related deaths. There were 80% paitents lose the chance of operation as a result of the transfer or contraindication when they have the onset of symptoms with lung cancer the first visit.The overall 5-year survival rate of lung cancer is 15%, less than 10% in China. The 5-year survival rate of lung cancer: IA 67%, IB 57%,â…¡A 34%,â…¡B 24%,â…¢B 6% ~ 8%,â…£of 3%. Therefore, early diagnosis of lung cancer 5-year survival rate for the increase is significant.DNA methylation as part of epigenetics can control gene expression. There are many genes that are found to be methylated at promoter region,and they are all associated with cancer, such as cell cycle genes, DNA repair genes, angiogenesis genes, apoptosis related genes, cell adhesion and migration-related genes, hormone receptor gene et al.Therefore, methylation is to become a new class of biomarkers and has become an effective diagnostic marker of cancer, is also becoming a promising potential target for cancer treatment. Many studies have shown that demethylation treatment can restore expression of some silencing gene because of DNA hypermethylation such as p16 that can control cell proliferation, differentiation and apoptosis genes ,and it will inhibit tumor cell growth, increased cell adhesion to restore sensitivity to chemotherapy, to achieve the purpose of cancer treatment. So,our purpose is to investigate the relationship of lung cancer related gene promoter methylation with lung cancer cell growth, differentiation, proliferation and apoptosis,and development, to evaluate the feasibility of methylation as early diagnosis and therapeutic targets.This topic selected NDRG2, P16, CDH1, RARbeta2, and WIF-1 candidate tumor suppressor gene, cultured lung cancer cells A549, GLC-82, control cell ECV-304, GES-1, extracted genomic DNA from cells, used pyrosequencing to detected some methylation loci on five genes after bisulfite treatment. The result showed that five genes had different degrees of DNA methylation in the four cells, the MTI of NDRG2, P16, RARbeta2 in lung cancer cells was highed than conreol cells .and the MTI of WIF-1 and CDH1was no significant difference between two groups.To investigate the relationship between gene promoter region methylation status and gene expression, we used 5-Aza-CdR to teartment lung cancer cells with two different concentrations and different time. The result showed that the expression of NDRG2, P16 and RARbeta2 was restored, suggested that the silence these three genes is associated with promoter hypermethylation in lung cancer cells.At present, most cancer research about gene methylat is based on clinical biopsy, but based on body fluids (plasma / serum, sputum, urine. Ascites, etc.) research is very little. In this study, we extracted genomic DNA from peripheral blood of lung cancer patients, used pyrosequencing to detected gene methylation.The result showed that the MTI of the NDRG2, P16 and CDH1 gene is higher in lung cancer patients group than conctrol group, and the statistic difference was significant(p<0.05), consisted with the literature. The MTI of WIF-1 is also higher in lung cancer patients group than conctrol group but the statistic difference was significant, maybe it is the bias from the detection of small sample size,detection loci and different methods.
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