miR-4324 functions as a tumor suppressor in colorectal cancer by targeting HOXB2

OBJECTIVE: MicroRNAs (miRNAs) are reported to have crucial roles in human cancers; however, their role in colorectal cancer (CRC) remains largely unknown. METHODS: In this study, we analyzed the expression of miR-4324 in CRC cell lines using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). We also examined miR-4324 expression in CRC tumor tissues using a miRNA expression dataset obtained from the Gene Expression Omnibus. We validated the connection between miR-4324 and homeobox B2 (HOXB2) using a luciferase activity reporter assay and western blotting. The effects of miR-4324 and HOXB2 on CRC cell malignant behaviors in vitro were further investigated. RESULTS: miR-4324 expression was significantly decreased in both CRC tumor tissues and cell lines. Overexpression of miR-4324 suppressed CRC cell proliferation, migration, and invasion. In contrast, overexpression of HOXB2 promoted CRC malignant cell behaviors. Furthermore, we validated HOXB2 as a direct target of miR-4324. CONCLUSIONS: miR-4324 expression was decreased in CRC. miR-4324 regulates CRC cell proliferation, migration, and invasion by targeting HOXB2.