Figure 3From: Frequent loss of endothelin-3 (EDN3) expression due to epigenetic inactivation in human breast cancerEndothelin (EDN) mRNA expression analysis in breast cell lines. (a) Alignment of the primary amino acid (aa) structure of human EDN1, EDN2 and EDN3 after post-translational cleavage to the biologically active 21-aa form [4]. The secondary structure consists of single α-helices containing two disulphide bonds that hold them in a conical spiral shape, joining cysteins at positions 1–15 and 3–11 [53]. EDN3 structure differs mainly in the NH2-terminal region from the structure of EDN1 and EDN2. This region forms a bulge out of the basic EDN structure and has been reported to represent a major domain for binding specificity to EDN receptors and thus is critical in endothelin signalling activity [29]. Numbers indicate consecutive aa residues, and aa residues are indicated in universal single-letter aa code. (b) Real-time polymerase chain reaction comparing EDN3 expression with EDN1 and EDN2 expression. While EDN1 is overexpressed in cancerous breast cell lines (MCF7, SKBR3, MDA-MB231 and BT20), EDN3 expression is abrogated in the same malignant cells as compared with MCF12A cells (set to 1 in each diagram).Back to article page