Poster presentations

Aims Endothelin, the most potent vasoconstrictor known has been implicated development and spread of malignancy. In this study, we assessed the produc endothelin-1 (ET-1) and its precursor big endothelin (big ET-1) by human cancer cel Methods Ten human cancer cell lines were cultured (lung n = 4, colorectal n = 3, gastro-oesophageal n = 2, pancreatic n = 1). The culture media were replaced wi fresh media after the cells attained confluence. After 48 hours, the conditioned were batch analysed for ET-1 and big ET-1 by using a sandwich enzyme l immunoassay (ELISA) (Biomedica, Austria). To elucidate the action of endot converting enzyme (ECE), big ET-1 was added to one of the oesophageal canc lines after they attained confluence. Similarly, the media were analysed fo presence of ET-1 and big ET-1 Results All the ten cancer cell lines produced ET-1 and nine of ten cancer cell produced big ET-1. ET-1 and big ET-1 were not produced in equimolar amounts ratio of ET-1 to big ET-1 was 0.56–11.88 (range). All three colorectal cancer cell and four of the lung cancer cell lines produced both ET-1 and Big Et-1. Interest the oesophageal cancer cell line that produced high concentrations of ET-1 d produce any measurable big ET-1. Addition of Big ET-1 into this cell line mediu assess the action of ECE, measuring ET-1 and big ET-1 after 48 hours resu complete cleavage of big ET-1 and there was no measurable big ET-1 in the me