Fig. 3

Hypermethylation of the p278 promoter region regulates miR-509-3p transcription. A mRNA expression levels of miR-509-3p in A2780CP70 cells treated with 1 or 10 µM 5-aza-2′-deoxycytidine (5-aza) for 5 days were evaluated using real-time RT-PCR. All experiments were performed in triplicate. ** P < 0.01, compared with the control. B Upper panel: The genomic position of miR-509-3p and two candidate methylation-regulated positions (p278: chr146,413,629 to 146,413,907) are shown. Lower panel: A2780CP70 cells were transfected with SssI methylated or unmethylated p278. Luciferase activity was almost null in the cells transfected with SssI methylated p278. All experiments were performed in triplicate; ** P < 0.01. C Representative bisulfite sequencing. D The invasive ability of A2780CP70 and OVCAR-8 cells treated with 5-aza (1 or 10 μM) for 5 days. All data represent the mean ± SD of three separate experiments; ** P < 0.01, compared with the control. E Ten-year overall survival (OS) and progression-free survival (PFS). Kaplan–Meier curves stratified by the miR-509-3p promoter methylation at position 1 (upper panel) and at position 2 (lower panel), analyzed using a log-rank test (n = 161)