MicroRNA-33b inhibits tumor cell growth and is associated with prognosis in colorectal cancer patients.

PURPOSE

To explore the role of miR-33b in colorectal cancer (CRC) and the correlation between its expression and prognosis.

METHODS

The expressions of miR-33b between CRC tissues and normal tissues were measured by real-time PCR. The effects of miR-33b on cell proliferation and cell cycle progression were detected by MTT assay, colony formation assay and flow cytometry. The potential regulations of miR-33b on multiple genes expression were verified by Western blot. Furthermore, the association of miR-33b with CRC clinicopathologic features and prognosis was analyzed by Chi-squared test and Kaplan-Meier tests.

RESULTS

MiR-33b was downregulated in CRC compared with normal colorectal samples and miR-33b inhibited tumor cell growth and induced cell cycle arrest. Western blot assays and correlation analysis showed that miR-33b could regulate multiple growth-related genes. Moreover, the expression of miR-33b was associated with TNM stage and tumor size, and CRC patients with high miR-33b expression had a better prognosis.

CONCLUSION

Our data suggest that miR-33b functions as a tumor suppressor gene in CRC through regulating cell proliferation and cell cycle.