LEIGC long non-coding RNA acts as a tumor suppressor in gastric carcinoma by inhibiting the epithelial-to-mesenchymal transition

Background: Long non-coding RNAs have been shown to have critical regulatory roles in cancer biology. However, the contributions of lncRNAs to gastric cancer remain largely unknown. Methods: The differential expression of lncRNAs in gastric cancer and paired non-cancerous tissues were identified by microarray and validated using quantitative real-time PCR. Gastric samples from patients with gastric cancer were further analyzed for levels of a specifically downregulated lncRNA (termed as LEIGC). Results: We found that there were significantly lower levels of LEIGC expression in cancer tissue than in adjacent non-cancerous tissues in human gastric cancers (P < 0.01). Overexpression of LEIGC suppressed tumor growth and cell proliferation, and enhanced the sensitivity of gastric cancer cells to 5-fluorouracil (5-FU), whereas knockdown of LEIGC showed the opposite effect. We further demonstrated LEIGC functions by inhibiting the epithelial-tomesenchymal transition (EMT) in gastric cancer. Conclusions: Our data suggested that LEIGC is a tumor-suppressing lncRNA in gastric cancer, and led us to propose that lncRNAs may play important regulatory roles in cancer development and progression.