Preliminary Study On The Expression And Function Of Long Non-coding RNA RP11-463O9.5 In Gastric Adenocarcinoma

Objective: To explore the expression level of LncRNA RP11-463O9.5 in gastric adenocarcinoma(GA) tissues and the relationship between LncRNA RP11-463O9.5expression levels and the clinical pathological features of patients with GA. To preliminarily explore the alteration of LncRNA RP11-463O9.5 expression level on affecting the biological behavior of GA cells. Finally, to predict LncRNA RP11-463O9.5 downstream target gene.Methods:(1) Gene chips of high flux assay were used to detect the expression profiling of LncRNA in GA tissues, screening out previously unreported with the statistically significant differential expressions of LncRNA as the targeted LncRNA for this research.(2) The expression levels of LncRNA RP11-463O9.5 in GA tissues were further verified by real time quantitative reverse transcription-polymerase chain reaction(qRT-PCR), and the relationship between LncRNA RP11-463O9.5 expression levels and clinical pathological features of patients was analyzed by the statistical methods.(3) Si RNA was used to knock-down the expression levels of LncRNA RP11-463O9.5 in GA cells, CCK-8 for cell proliferation assay, flow cytometry for cell apoptosis assay, wound healing for cell migration assay and Transwell for cell invasion assay were used to check the effects of silencing LncRNA RP11-463O9.5expression on affecting the biological behavior of GA cells.(4) The expression levels of FOXC2 in GA tissues was verified by qRT-PCR,the relationship between FOXC2 and LncRNA RP11-463O9.5 expression levels was analyzed by the statistical methods. Bioinformatics methods were used to predict the downstream target genes of LncRNA RP11-463O9.5, and to predict the molecular regulatory network of LncRNA RP11-463O9.5.Results:(1)More than 3000 differently expressed LncRNAs with statistically significant significance were obtained by Gene chips of high flux assay, including the over expression of Lnc RNA RP11-463O9.5, its up-regulated fold change is 19.76 compared to the paired adjacent non-neoplastic tissues.(2)The result of qRT-PCR showed that LncRNA RP11-463O9.5 was over expressed in GA tissues compared with the non-cancerous gastric tissues(P<0.05),and the over-expressive rate of Lnc RNA RP11-463O9.5 in GA tissues was 79.3%.The expression of LncRNA RP11-463O9.5 was statistically significantly associated with patient's TNM staging, lymph node metastasis, vascular invasion and nerve invasion of GA(P<0.05), but not associated with patient's age, sex, tumor location,tumor size, and differentiation grade(P?0.05).(3)The results of cell function tests showed that LncRNA RP11-463O9.5 was over expressed in the 4 different GA cells compared with the normal gastric epithelial cell GES-1(P<0.05). Silencing the expression of LncRNA RP11-463O9.5 in GA cells,significantly suppressing the proliferation, migration and invasion in GA cells(all P<0.05), but no affecting the apoptosis in the GA cells(P>0.05).(4)The result from qRT-PCR showed that FOXC2 was over expressed in the GA tissues compared with the non-cancerous gastric tissues(P<0.05), and the over-expressive rate of FOXC2 was 63.5% in cancer tissues. The expression of FOXC2 were positively correlated with the expression of LncRNA RP11-463O9.5with a correlation coefficient of 0.821(P<0.001). The result of predicting the downstream target genes showed that 30 genes may be the downstream target genes of LncRNA RP11-463O9.5.Conclusions: LncRNA RP11-463O9.5 was over-expressed in GA tissues, and its expression levels were statistically significantly associated with patient's TNM staging,lymph node metastasis, vascular invasion and nerve invasion of GA. Lnc RNA RP11-463O9.5 was also over expressed in the GA cells. Silencing LncRNA RP11-463O9.5 expression was able to inhibit the proliferation, migration and invasion in GA cells. FOXC2 was also over-expressed in the GA tissues, exhibiting a positivelycorrelated with the expression of LncRNA RP11-463O9.5. The results from our preliminary study indicated that LncRNA RP11-463O9.5 may be related with GA,and could have the potential to be used as a biomarker for GA.