RESUMO
To analyze the spatial distribution of tumor cell lines with different invasive properties, we used time-lapse videomicroscopic recordings associated with software programs we have developed for quantification. We observed that non-invasive tumor cells rapidly formed small clusters which aggregated to form larger clusters, whereas highly invasive tumor cells remained isolated and did not form clusters. An attraction index computed from a cellular automaton model was used to quantify the degree of attraction-repulsion between cells. The results suggest that the cluster formation by noninvasive cells is not related to a global attraction model and that the random (dispersed) distribution of invasive cells is not related to cell repulsion. According to these results, we can conclude that random cell movement combined with the intrinsic properties of cells explains the phenomenon of cluster formation.