AIM:To investigate the level of miR-218 in human retinoblastoma(RB)and its effect on the potential mechanism of tumorgenesis.

METHODS:Real-time PCR was applied to detect the expression of miR-218 in human RB and the corresponding tumor-adjacent tissues to analyze the relation between miR-218 and clinic pathology characteristics. The artificial miR-218 was transiently transfected into human Y79 cells in vitro. The proliferation and apoptosis of the cells were detected by MTT assay and flow cytometry, respectively. The expression level of Bmi-1 mRNA and protein were determined by RT-PCR and Western blot.

RESULTS:The expression level of miR-218 in RB tissues was significantly lower than that in the adjacent tissues, and it was associated with optic nerve infiltration and differentiated degree. Over-expressed miR-218 in Y79 cells suppressed cell proliferation and promoted cell apoptosis, and down-regulated mRNA and protein expressions of Bmi-1.

CONCLUSION:The expression of miR-218 in RB tissues is significantly lower than that in tumor-adjacent tissues.MiR-218 could inhibit RB cell proliferation and induce apoptosis by down-regulating the expression of Bmi-1.