Fig. 3

Promoter hypermethylation leads to downregulation of miR-199a-3p in ovarian cancer. a Representative agarose gel MSP images of two ovarian cancer cases with paired normal surrounding tissues. b miR-199a-3p and DDR1 levels in the two ovarian cancer cases of (a) were measured. *P < 0.05. c Methylation percentage of miR-199a gene in 15 ovarian cancer cases with paired normal surrounding tissues. The methylation percentage was estimated using the

following formula: methylatede(%) = 1/(1 + 2^CtU-CtM). d The hypermethylation levels of miR-199a gene promoters in IOSE386, SKOV3, and 5-Aza-dC treated SKOV3 cells were determined by bisulphite DNA sequencing showing eight independent clones from each group. e Relative level of miR-199a-3p in SKOV3 and HO-8910 cells after 5-Aza-dC treatment. *P < 0.05. f The protein level of DDR1 in SKOV3 and HO-8910 cells after 5-Aza-dC treatment. g SKOV3 cells were transfected with DNMT3A siRNA or control siRNA. ChIP sample was analysed using antibodies against IgG or DNMT3A. The antibody-promoter-binding signals were analysed by quantitative PCR. *P < 0.05. h-j SKOV3 cells were transfected with DNMT3A siRNA or control siRNA. The methylation levels of miR-199a gene promoter determined by MSP analyses (h), relative levels of miR-199a-3p measured by QPCR (i), and the protein levels of DDR1 detected by western blot (j). *P < 0.05