MiR-643 Functions as a Potential Tumor Suppressor in Gastric Cancer by Inhibiting Cell Proliferation and Invasion via Targeting TXNDC9.

Objective Gastric cancer is one of the most common gastrointestinal malignancies. miRNAs (microRNAs) have been reported to play a pivotal role in the tumorigenesis of gastric cancer. However, the role of miR-643 in gastric cancer is not fully understood. Methods The expression of miR-643 in gastric cancer cell lines was detected by qRT-PCR (quantitative reverse transcription PCR). Cell viability, apoptosis, migration, and invasion were assessed using the Cell Counting Kit-8 (CCK-8), colony formation, flow cytometry, and wound scratch and Transwell assays, respectively. The target gene of miR-643 was predicted by bioinformatics analysis and validated using luciferase reporter assay. Results The expression level of miR-643 in gastric cancer cell lines was lower than in the normal gastric epithelium cell line (GES-1). Overexpression of miR-643 inhibited cell viability and colony formation but promoted cell apoptosis in gastric cancer. Transwell invasion assay and in vitro scratch assay evidenced that miR-643 overexpression inhibited gastric cancer cell migration and invasion. Bioinformatics analysis revealed that miR-643 could directly target TXNDC9 (Thioredoxin domain containing 9), and luciferase reporter assay validated this result. Further analysis showed that miR-643 mimics caused a significant reduction of TXNDC9 in gastric cancer cells. Moreover, TXNDC9 overexpression reversed the effects of miR-643 mimics on gastric cancer cell viability, invasion, and migration. Conclusion miR-643 functions as a potential tumor suppressor in gastric cancer by inhibiting cell viability, colony formation, migration, and invasion via targeting TXNDC9, which provides a novel target for the diagnostic treatment of gastric cancer.