Dynamic behavior analysis of in-vitro cancerous cells by means of an automatic image-processing device

The study of in vitro cell motility has received a great deal of attention for many years. All former studies typically imply the use of a microscope equipped with a camera, a digitizer board and a computer that process the frames to evaluate cell motility. The present paper reports an improved device incorporating the typical components of in vitro cell motility analyzers, which also makes possible the evaluation of clustered cell motility, an important variable for assessing aggressiveness in cancer models. Two methods have been developed. The first avoids the segmentation step and thus provides a measurement of the motility of the whole cluster considered as a single entity. The second consists of a clustered cell tracking software developed in our laboratory. The segmentation process is performed by means of an algorithm based on watershed transformation applied to a modified gradient image. This gradient modification consists of a new algorithm using the correlation between the frames. As a result, the cells are extracted from the background and can be tracked through the sequence. A set of five experiments was performed on cell colonies from the PC-3 human prostate cancer in vitro model colonies in order to illustrate the features of the device.