A fluorometric rapid microassay to identify anti-proliferative compounds for human melanoma cells in vitro.

A simple, rapid and reproducible assay for the determination of melanoma cell proliferation in vitro is described, based on the hydrolysis of a fluorogenic substrate by cell esterases in the cytoplasm of living cells. Human melanoma cells were cultured at several densities in 96-well culture plates for 24 h and were then incubated with 4-methylumbelliferyl heptanoate. The generated fluorescence showed a strong correlation with the cell numbers, similar to those assessed by determining the [3H]thymidine incorporation into cellular DNA and by quantifying the fluorescence obtained after DNA labelling with Hoechst 33258. The latter, however, was less sensitive and exhibited higher standard deviations. In addition, the method reliably detected the anti-proliferative effects of the anti-cancer compounds cisplatin and vindesine. It is, therefore, suggested that the fluorometric assay with 4-methylumbelliferyl heptanoate as substrate could prove useful for the screening of potential anti-cancer agents with anti-proliferative activity.