Upregulation of miR-802 suppresses gastric cancer oncogenicity via targeting RAB23 expression.

OBJECTIVE: The aberrant expression of microRNAs (miRNAs) has been observed in various types of cancer. Recently, miR-802 was found to play important role in tumor progression. However, the function of miR-802 in gastric cancer (GC) remains unknown. The aim of the present study was to investigate biological effects and underlying mechanisms of miR-802 in GC.

PATIENTS AND METHODS: Quantitative RT-PCR was performed to evaluate the expression level of miR-802 in GC tissues and cell lines. The in vitro cell proliferation was measured using the MTT method. Cell invasion and migration assays were performed using the transwell assay. The effects of miR-802 on tumor growth were examined using a GC xenograft model. Flow cytometry method was used to detect the effect of miR-802 in apoptosis of GC cells. Targets of miR-802 were predicted using bioinformatics and validated using luciferase reporter and Western blot analyses.

RESULTS: The results showed that miR-802 was significantly down-regulated in GC tissues and cell lines. The enforced expression of miR-802 induced growth suppression and apoptosis of GC cells. Moreover, miR-802 overexpression suppressed the migration and invasion of GC cells. Bioinformatics analysis predicted that the RAB23 was a potential target gene of miR-802. The results of luciferase reporter assay demonstrated that miR-802 could directly target RAB23. Additionally, in vivo analysis, the xenograft mouse model also confirmed the suppressive effects of miR-802 on tumor growth.

CONCLUSIONS: Our results are the first to demonstrate the tumor-suppressive role of miR-802 in GC. The identification of miR-802 and its novel target RAB23 will be valuable in developing therapeutic applications for GC.