microRNA-217 suppressed epithelial-to-mesenchymal transition through targeting PTPN14 in gastric cancer (Publication with Expression of Concern. See vol. 40, 2020)

Background: Gastric cancer (GC) is the one of most common malignancies and its mechanism of metastasis remains unclear. The study was designed to investigate the effects of microRNA-217 on epithelial-to-mesenchymal transition. Methods: The expression levels of miR-217 in GC were assayed by real-time qPCR. Metastasis and invasion of cancer cell were assayed by transwell chamber. Double luciferase reporter gene was used to verify the target regulatory relationship between microRNA-217 and tyrosine-protein phosphatase non-receptor type 14 (PTPN14) on gastric cell lines. Epithelial-to-mesenchymal transition (EMT) markers were assayed by Western blot. Results: We found that miR-217 had a low level expression in gastric tumor tissues of 40 patients with GC, and a lower expression in the gastric tumor tissues of the patients with GC metastasis. Moreover, miR-217 markedly suppressed the metastasis and invasion of gastric cancer cell line in vitro. Furthermore, miR-217 inhibited the expression of PTPN14 by directly targeting its 3'UTR. Moreover, the down-regulation of PTPN14 reduced the metastasis and invasion, whereas up-regulation of PTPN14 led to the enhanced metastases and invasion of gastric cells. miR-217 induced the down-regulation of PTPN14 and inhibited the EMT in gastric cancer cells. Conclusion: miR-217 inhibited the EMT through directly targeting to the 3'UTR of PTPN14.