| Part One The expression level of lncRNA RP11-6O2.4 in gastric cancer tissue and gastric cancer cell lines and its correlation with patients' clinicopathological featuresObjective:(1)To investigate the expression level of lncRNA RP11-6O2.4 in gastric cancer tissue and gastric cancer cell lines.(2)To investigate the relationship between the expression level of RP11-6O2.4 and patients' clinicopathological features.Method:(1)lncRNA microarray was used to detect the expression level of lncRNA between gastric cancer tissue and adjacent normal tissue,and lncRNA was filtered out for more than 10 times.Finally,the lncRNA RP11-6O2.4 was identified as the target lncRNA.(2)The expression level of RP11-6O2.4 in 100 gastric cancer tissues and paired adjacent normal tissues was detected by Real-Time PCR.(3)The expression level of RP11-6O2.4 was compared between gastric cancer cell lines: MGC-803,BGC-823,SGC-7901,AGS and normal gastric epithelial cell line GES-1 by Real-Time PCR.(4)The clinical and pathological data of 100 patients were collected and the relationship between lncRNA RP11-6O2.4 and clinicopathological features was analyzed.Results:(1)The expression level of RP11-6O2.4 in gastric cancer tissue was significantly lower than adjacent normal tissue(p < 0.05).(2)The expression level of RP11-6O2.4 in gastric cancer cell lines was significantly lower than normal gastric epithelial cell(p<0.05).(3)The expression level of RP11-6O2.4 was correlated with patients' age,the size of tumor volume,the depth of invasion(T stage),ASA grade(p<0.05).(4)The clinical diagnostic value of RP11-6O2.4 was evaluated by the Area Under Curve(AUC)of ROC curve.The result of AUC was 0.6817,which suggested there was a certain clinical diagnostic value about RP11-6O2.4(p<0.05).Conclusion: The expression level of RP11-6O2.4 in gastric cancer tissue and gastric cancer cell lines was significantly lower than adjacent normal tissue and normal gastric epithelial cell,and its down-regulation is correlated with higher patients' age,greater tumor volume,deeper tumor invasion degree,higher ASA grade.RP11-6O2.4 also has a certain clinical value for gastric cancer diagnosis.Part Two Study on the Mechanism of LncRNA RP11-6O2.4 in the Regulation of Biological Behavior of Gastric Cancer Objective: To investigate whether RP11-6O2.4 is involved in the regulation of biological behavior of gastric cancer and its possible molecular mechanism.Method:(1)The expression of the classical signal pathway was confirmed by Real-Time PCR and Western Blot in gastric cancer tissues with the lower expression level of RP11-6O2.4,and it was presumed whether it was involved regulation of biological behavior of gastric cancer cells.The ASK1-p38-cyclin D1 signaling pathway was found to be significantly up-regulated.(2)In vitro experiments,we used p38 inhibitor to down-regulate ASK1-p38-cyclin D1 signaling pathway to observe whether the expression of lncRNA RP11-6O2.4 in different gastric cancer cell lines changed accordingly..(3)The proliferation and apoptosis of gastric cancer cells treated with p38 inhibitor were detected by flow cytometry.Results:(1)The expression of ASK1-p38-cyclin D1 was significantly up-regulated(P <0.05)in the tissues with reduced RP11-6O2.4 expression(p< 0.05).(2)The expression of lncRNA RP11-6O2.4 was significantly increased after treated with p38-specific inhibitor SB203580 in gastric cancer cell lines MGC-803,BGC-823,SGC-7901 and AGS(P <0.05).It hinted that lncRNA RP11-6O2.4 was involved in the regulation of proliferation activity of gastric cancer cells via ASK1-p38-cyclin D1 signaling pathway.(3)In the most obvious AGS cells with reduced RP11-6O2.4,we further detected the expression of several key proteins in ASK1-p38-cyclin D1 signaling pathway,ASK1 expression was significantly up-regulated(p <0.05),cyclin D1 was significantly down-regulated(p <0.05).The result of AGS cells by flow cytometry showed that the proportion of G1 phase cells was significantly increased,and the proportion of S phase cells decreased significantly,which indicated that the cell proliferation activity was obviously inhibited.Conclusion: The ASK1-p38-cyclin D1 signaling pathway was significantly activated in tissue samples with lower RP11-6O2.4 expression,p38 expression was significantly up-regulated.In vitro experiments,after gastric cancer cell lines were treated with with p38-specific inhibitor,The expression of lncRNA RP11-6O2.4 was significantly increased and the cell proliferation activity was obviously inhibited.Combined with the clinical analysis,we speculated that RP11-6O2.4 may be involved in the regulation of proliferation activity of gastric cancer cells via ASK1-p38-cyclin D1 signaling pathway. |
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