CHARACTERIZATION OF THE DIFFERENTIATION OF HUMAN COLORECTAL-CANCER CELL-LINES BY MEANS OF VORONOI DIAGRAMS

This paper describes differentiation in terms of population dynamics t hrough the medium of Voronoi paving which enables (via digital cell im age analysis) the structure of human LOVO and HCT-15 colorectal neopla stic cell colonies growing on histological slides to be characterized. Two other tests were also used, i.e., the colorimetric MTT assay that enables the cell growth level to be determined, and a test allowing t he assessment of the proliferation index, i.e., the percentage of cell s in the S phase of the cell cycle. The results show that these colore ctal neoplastic cells exhibited a comparatively high level of organisa tion in terms of the topographical distribution of nuclei within the c lones when the cells were cultivated in media containing even small am ounts of fetal calf serum. On the other hand, certain chemically defin ed media completely overturned this ''pseudo-tissular'' architecture. Furthermore, the colorectal cells growing in media including fetal cal f serum exhibited relatively large and dense clones, undergoing an inc rease in the density of these clones when hormones were added to the c ulture medium and, concomitantly, a decrease in their proliferation. I n contrast, the cells growing in chemically defined media generally ex hibited smaller clones whose cell proliferation was paradoxically grea ter than that of the cells referred to above. This seems to bring out the importance of the part played by the cell loss factor in this cell population dynamic. (C) 1993 Wiley-Liss, Inc.