SYTO probes in the cytometry of tumor cell death.

Apoptosis is a complex and finely controlled cell death process of great relevance in tissue homeostasis and pathogenesis. The majority of classical apoptotic features can be examined by flow as well as image cytometry. Therefore, cytometry has been used as a technology of choice in studies of tumor cell demise. As search for new and more effective anticancer agents is still ongoing, there is undoubtedly a need for further development of high-throughput screening platforms. Assays that allow multivariate characterization of cell death events in response to novel anticancer regimens are of particular significance. In this context, patented DNA-binding SYTO probes are gaining increasing interest as easy to use markers of caspase-dependent cell death. They are proving convenient for tracking apoptosis in diverse cell lines as well as in primary tumor samples. In this review, we outline most recent developments in the use of SYTO probes in cell necrobiology. We also present pilot characterization of novel SYTO orange stains (SYTO80 and SYTO81) and discuss their potential applications in cytometry of apoptosis. Finally, we provide a future outlook on SYTO probes in cytometric and microfluidics (Lab-on-a-Chip) high content analysis applications. (c) 2008 International Society for Advancement of Cytometry.