Multiphoton microscopy allows us to follow specific cellular structures (ie. nuclei, mitochondria, and the plasma membrane) in a high resolution three dimensional and time resolved fashion. We have used multiphoton confocal microscopy to evaluate the cellular effects of potential cancer therapeutics. Cancer cells were plated onto coverslips and labelled with either the vital DNA dye Hoechst to image the nuclei and chromosomes or the lipid dye DiA to label the plasma membrane. Both of these dyes can be imaged with several sections without affecting cell viability as assessed by cell motility and the ability to undergo mitosis and cytokinesis.

We have used this technology to show that one compound (DDE 131) rapidly induces in cancer cell lines the hallmarks of apoptosis; DNA hypercondensation, nuclear fragmentation and rapid membrane blebbing. In a leukemic cell line these changes take place within 20 minutes of treatment.