MicroRNA-485 plays tumour-suppressive roles in colorectal cancer by directly targeting GAB2

Abstract

Colorectal cancer (CRC) is reported to be the third most common cancer and the fourth leading cause of cancerrelated deaths around the world. MicroRNA-485 (miR-485) has been reported to be aberrantly expressed and play important roles in several types of human malignancy. However, the expression level, biological functions and underlying molecular mechanisms of miR-485 in CRC remain unclear. Therefore, the aim of the present study was to determine miR-485 expression levels and their clinical signifcance in CRC and to explore the functions and underlying mechanisms of miR-485 in this disease. In the present study, miR-485 was lowly expressed in CRC tissues and cell lines. Decreased miR-485 expression was associated with tumour size, lymph node metastasis, distant metastasis and TNM stage. Functional assays indicated that upregulation of miR-485 impaired CRC cell proliferation, invasion and induced cell apoptosis. Grb2-associated binding 2 (GAB2) was identifed as a direct target of miR-485 in CRC. GAB2 was upregulated in CRC tissues and was negatively correlated with the miR-485 expression level. Furthermore, GAB2 knockdown simulated the tumoursuppressing roles of miR-485 overexpression in CRC cells. Moreover, restored GAB2 expression reversed the effects of miR-485 overexpression in CRC cells. In addition, miR-485 suppressed the AKT and ERK signalling pathways in CRC by directly targeting GAB2. Collectively, these fndings demonstrate that miR-485 may play tumour suppressive roles in CRC by directly targeting GAB2 and indirectly regulating AKT and ERK signalling pathways, suggesting that miR-485 may be a potential therapeutic target for patients with this disease.