MiR-489 suppresses tumor growth and invasion by targeting HDAC7 in colorectal cancer.

Purpose: The expression of miR-489 is linked to tumor development and progression; nevertheless, its role in tumor growth and invasion of colorectal cancer (CRC) and the underlying mechanism has not been clarified.

Experimental Design: We used quantitative RT-PCR to measure the expression of mature miR-489 in human colorectal tissues and the corresponding CRCs. Targets of miR-489 were predicted with TargetScan and substantiated by dual-luciferase reporter assay. Furthermore, we did in vitro and in vivo analysis with expression vectors and small interfering RNAs, to elucidate the precise role of miR-489 and its target gene histone deacetylase 7 (HDAC7) on cell proliferation, survival, and invasion.

Results: Compared to the corresponding non-tumor tissues, miR-489 was frequently downregulated in CRC. By Kaplan-Meier analysis, we found that lower CRC recurrence free survival years in the group with elevated miR-489 expression than those with lower miR-489 expression. In addition, we examined that miR-489 obviously inhibited the migratory and invasive capability in CRC. In further study, we found that miR-489 targets the 3'-UTR of the HDAC7 transcript and downregulates its expression, and HDAC7 expression promoted tumor cell proliferation and invasion. We demonstrated that miR-489 suppresses tumor invasion and metastasis in CRC by targeting HDAC7.

Conclusions: We identified that MiR-489 suppresses tumor growth and invasion in CRC by targeting HDAC7. The expression of miR-489 suggests CRC recurrence and metastasis, which shed crucial light on how miR-489 functions in CRC pathogenesis.