Quantitation of apoptosis induction by etoposide or hydroxyurea in mouse interleukin 3-dependent lymphoma cells.

BACKGROUND: The apoptosis induction by etoposide or hydroxyurea in mouse interleukin 3-dependent lymphoma cells (DA-1) was studied. Treatments with 1.25 mM hydroxyurea and 100 microM etoposide for 17 hours were considered appropriate concentrations for such studies. MATERIALS AND METHODS: The viability of the cells was studied by propidium iodide exclusion. The presence of apoptotic bodies was observed, and DNA fragmentation of apoptotic cells was asessed by the observation of ladder patterns in agarose electrophoresis gels and an increase in the proportion of cells with subdiploid DNA content in cytometric studies. RESULTS: Alterations of membrane properties, DNA degradation and chromatin condensation highlighted a possible apoptotic process induced by these two antitumor agents. CONCLUSION: These studies have established conditions for examining apoptotic processes in interleukin 3-dependent lymphoma cells. This is of great interest for deeper analysis of the mechanisms involved in the apoptosis of these cells after interleukin 3 depletion or treatment with cytotoxic antitumor compounds.