Time dependent appearance of selected apoptotic markers and usefulness of their detection in vitro.

Many experiments have demonstrated that some cell lines are resistant to chemically induced apoptosis in vitro, and that apoptosis itself is far from being a homogenous phenomenon. Here we show that 10 microg/ml etoposide elicited only minor changes in Bowes human melanoma cells (temporary decrease in cell viability and proliferation, transient phospatidylserine externalization and caspase-3 activation), which weren't clearly capable to start apoptotic pathway in the entire treated population. On the other hand, potassium chromate at concentration of 150 microg/ml executed cell death bearing some features of apoptosis (cell blebbing, caspase-3 activation and cytoskeletal changes) but lacking or showing weakly others (DNA fragmentation and phospatidylserine externalization). Our results suggest that in detecting apoptosis several fault-proof detection systems are to be used to avoid misleading results and conclusions in each experimental setting.