The Function Of IncRNA UCA1in Gastric Cancer And Identification Of Plasma RNAs As Potential Biomarkers Of Gastric Cancer

As a medical problem, cancer has been one of the most serious diseases threatening human health. Gastric cancer (GC) is one of the malignant tumors with the highest sick rate and case mortality rate in Asia even in the worldwide. But there is lack of effective means of diagnosis and treatment on clinical, and after operation, the patients usually survived with poor quality of life. So, it is significant to study the pathogenic mechanism of gastric cancer, to find the therapeutic targets, and to develop a biochemical diagnosis method. LncRNAs play important roles during the development of cancer, and there is few researches on the function of lncRNA in gastric cancer, it shows that we can focus on lncRNA in our study. On the other hand, try to find RNA tumor markers in the plasma with high sensitivity and specificity is our goal, too.In the first part of our study, using high‐throughput sequencing technology and real‐time PCR to detect expression of lncRNA in GC samples, we found UCA1were differently expressed in GC compared with adjacent normal tissues. Ectopic expression of UCA1increased the growth of gastric cancer cell and led to the motility of gastric carcinoma cells in vitro, while downregulation of UCA1could inhibit gastric cell proliferation, and lead to the arrest of cell cycle. We also found the expression level of UCA1influenced the drug resistance of gastric cancer cells, such as doxorubicin. Interestingly, when the concentration of doxorubicin get500μg/μl, the survival ratio of cells was increased, and it might be the result of UCA1. The expression of UCA1was simulated by doxorubicin, and it depended on p53. In the second part, we used GeneChip Human Transcriptome Array2.0and real‐time PCR to screen RNA tumor markers in plasma of GC patients, and analyzed them according to the age, sex, tumor stage and the size of tumor. We also assessed the sensitivity and the specificity of these RNA as biomarkers. In the third part, we established and optimized the one‐step method to extract miRNAs from plasma, and the new method is easy and low‐cost, and consumes less plasma. In summary, our study found the function of UCA1in gastric cancer, screened new RNA tumor biomarkers in plasma with new means and established and optimized the one‐step method to extract miRNAs from plasma.