miR-422a is an independent prognostic factor and functions as a potential tumor suppressor in colorectal cancer.

ABSTRACT

AIM: To determine the expression of miR-422a in colorectal cancer (CRC) tissues and to further explore the prognostic value and function of miR-422a in CRC carcinogenesis. METHODS: miR-422a expression was analyzed in 102 CRC tissues and paired normal mucosa adjacent to carcinoma by quantitative real-time PCR. The relationship of miR-422a expression with clinicopathological parameters was also analyzed. Kaplan-Meier analysis and Cox multivariate analysis were performed to estimate the potential role of miR-422a. Cell proliferation, migration, and invasion were used for in vitro functional analysis of miR-422a. RESULTS: The levels of miR-422a were dramatically reduced in CRC tissues compared with normal mucosa (P < 0.05), and significantly correlated with local invasion (P = 0.004) and lymph node metastasis (P < 0.001). Kaplan-Meier survival and Cox regression multivariate analyses revealed that miR-422a expression (HR = 0.568, P = 0.015) and clinical TNM stage (HR = 2.942, P = 0.003) were independent prognostic factors for overall survival in CRC patients. Furthermore, in vitro experiments showed that overexpression of miR-422a inhibited the proliferation, migration, and invasion of SW480 and HT-29 cells. CONCLUSION: Down-regulation of miR-422a may serve as an independent prognosis factor in CRC. MiR-422a functions as a tumor suppressor and regulates progression of CRC.