Figure 1.

CpG island hypermethylation-associated silencing of the miR-200 family in human cancer cell lines. (a) Schematic depiction of miR-200ba429 and miR-200c141 genomic loci. CpG islands (blue boxes) and transcription start sites (arrows) are shown. (b) Bisulfite genomic sequencing analysis of miR-200ba429 and miR-200c141 CpG islands in cancer cell lines. Six single clones are represented for each cell line. Location of bisulfite genomic sequencing PCR primers (black arrows) and CpG dinucleotides (vertical lines) are shown. Presence of unmethylated or methylated CpGs is indicated by white or black squares, respectively. (c) Expression of mature miRNAs of the miR-200 family in cancer cell lines, evaluated by qRT–PCR. Data represent relative quantification (mean±s.d.). (d) Restored mature miR-200 expression upon treatment with DNA-demethylating agent 5-aza-2′-deoxycytidine (aza) in miR-200 CpG island methylated cell lines (Student's t-test P<0.05 in all experiments).