Downregulation of cell cycle-related proteins in ovarian cancer line and cell cycle arrest induced by microRNA.

Objective: The effect of miR-449 and miR-34 on the growth, cell cycle and target gene expressions of ovarian cancer cell line SKOV3 and SKOV3-ipl was discussed.

Method: Real-time quantitative reverse transcription PCR was employed to detect the expressions of miR-449a/b and miR-34b, c in SKOV3 and SKOV3-ipl cells. The two miRNAs were successfully expressed in SKOV3-ipl cells by transfection. The variations in cell growth rate and cell cycle were determined by MTS assay and flow cytometry, respectively. The expressions of cell cycle-related proteins were detected by Western Blot.

Results: miR-449b and miR-34c induced the decline of the adhesiveness of SKOV3-ipl cells by 20%-30%. The number of cells arrested in G1-phase increased and the number of cells arrested in S-phase decreased significantly. The cell cycle-related proteins CDK6 and CDC254 were downregulated. miR-449b caused the expression of CDK6 and CDC25A to decrease. After the co-transfection with miR-449b and miR-34c, the relevant proteins were downregulated more significantly. The expressions of CDK6, CDC25A and cyclin A were decreased significantly.

Conclusion: miR-449b and miR-34c can induce cell cycle arrest in SKOV3-ipl cells and the downregulation of CDK6, CDC25A and cyclin A.