Toxicological and Pharmacological Evaluation of New Drug Candidates by in Vitro Robotic High-Throughput Cell Assays

Abstract

A high-throughput cell-based fluorescence screening assay was used to determine the cytotoxic activity of various cytostatic reference agents, unknown compounds of natural sources and pharmaceutic standard excipients in different cell lines such as HEK-293 and DLD-1 cells. In this paper we exemplarily show results for a selection of compounds and excipients. The cytostatic agent piposulfan has a much higher cytotoxic activity in DLD-1 cells (EC50=0.001 mg/mL) than in HEK-293 cells (EC50=0.3 mg/mL) in contrast to busulfan and vinblastine where the EC50 values are close together in both cell lines. From 113 tested compounds from natural sources the cytotoxic activity of 75 compounds showed no difference in both cell lines, 34 of them had a higher activity in HEK-293 cells than in DLD-1 cells and 4 compounds showed less cytotoxic activity in HEK-293 cells than in DLD-1 cells. We demonstrate the rather potent cytotoxic action of Cremophor EL; this finding is in accordance with previously published observations. The presented results demonstrate that the used assay system is reliable, enables the ranking of the cytotoxic potential of compounds of various chemical classes, and allows the determination of cell type-specific cytotoxicity. (JALA 2004;9:159-62)