MiR-802 Suppresses Colorectal Cancer Cell Viability, Migration and Invasion by Targeting RAN

Purpose: Colorectal cancer is one of the most malignant tumors in the world, and the incidence is increasing every year. MicroRNAs (miRNA) are small non-coding RNAs that are involved in a variety of physiological or pathological processes. Abnormal expression of microRNA-802 (miR-802) has been demonstrated in various types of cancer. However, the expression and biological role of miR-802 in human colorectal cancer remain largely unknown. Methods: Here, we used quantitative real-time PCR (qRT-PCR) to measure miR-802 expression levels in colorectal cancer tissues and cell lines. Cell Counting Kit-8 (CCK-8) was used to assess the effect of miR-802 on colorectal cancer cell viability. Migration and invasion assays were performed to determine the effect of miR-802 on metastasis of colon tumor cells by transwell analysis. Luciferase activity assays were used to confirm the target of miR-802. Results: The results show that miR-802 is significantly downregulated in colorectal cancer tissues and cell lines. Overexpression of miR-802 profoundly inhibited viability, migration and invasion of colorectal cancer cells. In addition, we have newly discovered that the Ras-associated nucleus (RAN) is a direct target of miR-802 which could reverse the effects induced by miR-802 overexpression in colorectal cancer cells. Conclusion: In conclusion, our study shows that miR-802 is downregulated in colorectal cancer, and overexpression of miR-802 inhibits colorectal cancer cell viability, migration and invasion by directly targeting RAN.