Determination of cell colony formation in a high-content screening assay.

The use of cell colony formation assays for research and clinical applications to assess the functional integrity of cells after in vitro manipulations is extensive. Key areas include hematopoietic stem cell research, cell transformation studies, and predicting the response of tumors to chemotherapeutic agents. Traditionally, enumeration of colonies has involved laborious and subjective counting by hand using a microscope. Here, laser scanning microplate cytometry has been used to provide an automated high-content readout of the effects of cytostatic agents on colony formation. This approach determines colony number through the application of a volume algorithm. Such an approach permits the differentiation of cytostatic effects where the number of colonies and size remains constant, and cytotoxic effects where the size and number may be reduced. Application of microplate cytometry thus offers significant benefits over alternative analytical methods in the search for novel chemotherapeutic agents.