MicroRNA-200c Expression In Gastric Cancer And Its Target Gene Prediction

Objective: Gastric cancer is one of the common malignant tumors inChina. It is a serious threat to human health because of the high morbidityand mortality. Due to the lack of timely and effectively early screeningmechanism, many patients are at an advanced stage when first diagnosed,and therefore lost the opportunity for surgery. Compared with othermalignant tumors, the prognosis of gastric cancer is worse. Researchingthe mechanism of gastric at gene and molecular level may helpful tofind a special marker for the early diagnosis of gastric cancer and providenew treatments for gastric cancer. miRNA is a endogenous non-codingsmall RNA molecules containing21-23nucleotides that do not encodeproteins. By acting on the specific mRNA3’untranslated region (UTR)induce target mRNA degrading or suppressing mRNA translation. Inrecent years, people found that miRNAs play an important role in theprocess of the occurrence, development and prognosis of malignantdisease. Differentially expressions of miRNAs in gastric cancer tissueshave become a hot topic in recent research.The family of miRNA-200contain5members: miR-200b/a/429and miR-200c/141. In different cellsand tissues they are often used as cancer-suppressing genes orcancer-promoting genes, and they are might be related with tumor celldifferentiation, proliferation, invasion, migration and metastasis. Thisstudy explored the difference expression of miRNA-200c in patientsbetween gastric cancer and adjacent normal tissue by real-timequantitative PCR, we also detected the relevance of the expression ofmiRNA-200c and clinical pathological dates. Using gene predictionsoftware and bioinformatics methods, we screened the relevant targetgenes of miRNA-200c, and studied the functions of target genes with GO analysis, providing new ideas and basis for the diagnosis and treatment ofgastric cancer.Method:1Select27cases of surgical gastric cancer organizations and theircorresponding adjacent normal gastric tissue in the Fourth AffiliatedHospital of Hebei Medical University during2011.3to2011.6.2Use real-time quantitative PCR method to detect the expressionlevel of miRNA200c in27patients with gastric carcinoma and adjacentnormal tissue, and collect the clinical and pathological datas of27patients with gastric cancer such as Gender, Age, Tumor size, Invasivedepth, Lymph node metastasis, TNM stage, Histologic, Intravascularcancer embolus, Borrmann3Select target genes of miRNA-200c as research targets usingbioinformatics approach, which can be predicted by all the three software:miRanda, TargetScan, PicTar. Select the shared genes and do significantgene function analysis with GO-Analysis, sorting by p value. The smallerthe P value, the greater relevance is.4Statistical analysis: Using SPSS13.0software, mean±standarddeviation（±s） was used to expressed measurement data, and paired ttest was used to compare the miRNA-200c expression levels between thetest group, the control group, and the clinical and pathological features ofgastric packet differences. p<0.05was considered statistically significant.Results:1The relative expression levels of miRNA-200c is lowered ingastric cancer tissues than normal tissues. Expression level of85.18%(23/27) gastric cancer tissues degraded. CT value of gastric cancertissues is0.59933±2.819735, while the CT value of adjacent normaltissue is-1.33063±2.309265, p <0.05.2miRNA-200c expression level of gastric cancer tissues is relevantwith histological grade and vascular invasion, and has no relevance withother clinic pathological parameters. There are15cases of G2and12cases of G3, the expression of miRNA-200c were0.204(0.013-1.471), 0.038(0.001-0.59), p<0.05; there are20vascular invasion cases,7non-vascular cases, miRNA-200c expression levels were0.069(0.001-0.723),0.277(0.02-1.471), p <0.05.3Using bioinformatics approach, there are24predicted target genesof miR-200c which are listed as follows: PDIK1L、FN1、PLK2、PPM1E、ELAVL2、RHOA、EFNB2、GPM6A、MXD4、PUM2、MAP4K3、NOG、QKI、EP300、NAB1、PCSK2、PTPN12、PCDH8、ANLN、PTPRZ1、KHDRBS1、POLK、FNDC3B、PDCD10. Factors involved withthe functions of target genes are: combining with ATP, GTP, variousproteins, the SMAD, metal ions, ephrin receptors, hormone receptors,specificity, DNA, mRNA, RNA, nucleotides, etc, and participate in signaltransduction, regulation of phosphorylation, calcium channel activity,regulating GTP activity of the enzyme, and repairing damaged DNA.GO-analysis results show that the major target genes of miRNA-200cinvolved in anatomical structure formation, the process of proteinmetabolism, cell biological processes regulating the development of thenervous system, macromolecule metabolic process, the development ofthe organism, regulating the process of translation, protein modificationand so on.Conclusion:1Low expression level of miR-200c in gastric cancer tissuesprompts that miR-200c may play a role as a tumor suppressor gene.2The expression level of miRNA-200c is related with thedifferentiation degree of gastric cancer and the presence of vascularinvasion and has no relevance with othe clinic pathological parameters.The results suggest that miRNA-200c may be an marker assessing gastricmalignancy, and may become the treatment target. miRNA-200c mayhave a guiding role for the prognosis of gastric cancer.3Bioinformatics research show that there are about20predictedtarget genes of miRNA-200c by prediction software. It takes effectsmainly by acting on the formation of the anatomical structure, biological regulation, intracellular protein metabolic process, cell biologicalprocesses regulating protein metabolism, regulating biological processes,the development of the nervous system and intracellular macromolecularmetabolism, and so on. For predicted target genes, there is a need forfurther experimental verification. The experiment can take method ofLuciferase reporting gene carrier.Bioinformatics can lay a foundation forresearch of miRNA-200c in target genes aspects.