High expression of LncRNA CASC15 is a risk factor for gastric cancer prognosis and promote the proliferation of gastric cancer

Objective: To investigate the expression of long non-coding RNA CASC15 in gastric cancer tissue and its effect on the proliferation of gastric cancer cell line MKN28.

Materials and methods: We found that expression of lncRNA CASC15 in gastric cancer tissue was higher than normal gastric epithelium through the TCGA and Gene Expression Omnibus (GEO) database. Then, we detect the RNA level of CASC15 from clinical samples of 42 normal gastric epithelial tissues and 60 gastric cancer tissues. In order to explore the function of CASC15 in gastric cancer, we perform gain-function and loss-function assay in gastric cancer cell lines.

Results: We found that expression of lncRNA CASC15 in gastric cancer tissue was higher than normal gastric epithelium through the TCGA database and the related microarray data set was searched from Gene Expression Omnibus (GEO) database. Then, we extracted total RNA from clinical samples of 42 normal gastric epithelial tissues and 60 gastric cancer tissues. The results of quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) were consistent with those of TCGA analysis. Clinical data analysis showed that the expression of LncRNA CASC15 was correlated with the total survival, tumor size and TMN staging in clinical patients. Clinical data analysis showed that the expression level of CASC15 was correlated with tumor size and TNM stage in clinical patients. Compared with the negative control group, the proliferation and cell cloning ability of MKN28 cells overexpressing LncRNA CASC15 significantly increased (p<0.001), indicating that overexpression of LncRNA CASC15 promoted the proliferation of MKN28 cells.

Conclusions: The expression of LncRNA CASC15 was significantly higher in gastric cancer tissues and its expression was negatively correlated with the overall survival of clinical patients. It was positively correlated with the tumor size and TMN stage. LncRNA CASC15 could promote the proliferation of gastric cancer cells and was expected to become the molecular marker for prediction and prognosis of gastric cancer, as well as a potential therapeutic target.