Figure 1From: Wnt signalling in human breast cancer: expression of the putative Wnt inhibitor Dickkopf-3 (DKK3) is frequently suppressed by promoter hypermethylation in mammary tumoursDKK3 mRNA expression and DKK3 promoter methylation analysis in breast cell lines. (a) DKK3 mRNA expression is differentially expressed in breast cell lines. Non-cancerous cell lines (HMEC and MCF12A) and cancerous breast cell lines (Hs578T, SKBR3, BT20, MCF7, MDA-MB231, T47D and ZR75-1) were analysed by realtime PCR and related to DKK3 mRNA expression in human placental tissue (set to 1). Grey bars = samples expressing abundant DKK3 mRNA; black bars = samples showing strong downregulation of DKK3 expression. (b) Hypermethylation of the DKK3 promoter in breast cell lines. Methylation specific PCR (MSP) was performed with bisulphite-treated DNA from benign and malignant breast cell lines. DNA bands in lanes labelled with U indicate PCR products amplified with primers recognising unmethylated DKK3 promoter sequence. DNA bands in lanes labelled with M represent amplificate generated with methylation-specific primers; water served as 'no template control' (NTC). MSP controls demonstrate the specificity of the DKK3 primers used. Universal poly-methylated bisulphite-converted DNA (UMD) exclusively yields amplification products with primers specific to methylated DKK3 promoter sequence; universal unmethylated bisulphite-converted DNA (UUD) yields exclusive amplification products with primers recognising the unmethylated DKK3 promoter sequence.Back to article page