COLCEMID-INDUCED APOPTOSIS OF CULTURED HUMAN GLIOMA - ELECTRON-MICROSCOPIC AND CONFOCAL LASER MICROSCOPIC OBSERVATION OF CELLS SORTED IN DIFFERENT PHASES OF CELL-CYCLE

The effect of the antitubulin agent colcemid on human glioma cells was investigated by sorting cells with different DNA content and subjecti ng them to confocal laser microscopy and transmission electron microsc opy. The human glioma cell line U251MG was exposed to colcemid at a co ncentration of 0.05 mu g for 16 h. Flow cytometric analysis revealed t he accumulation of cells in S/G2M phase. Cells harvested from each of G0/G1 and S/G2M peaks were then analyzed by confocal laser microscopy and transmission electron microscopy. Confocal laser microscopy reveal ed that colcemid-treated cells harvested from the G0/G1 peak contained mitotic and apoptotic cells in addition to interphase cells. Electron microscopy confirmed that colcemid-treated cells in the G0/G1 peak ha d fragmented nuclei typical of apoptotic cells and mitotic cells with altered chromatin structure. Some mitotic cells obtained by mitotic sh ake-off after treatment with colcemid showed DNA strand breaks defined by in situ nick end labeling. The present study indicates that mitoti c as well as interphase apoptosis occurs in U251MG cells following col cemid treatment. (C) 1998 Wiley-Liss, Inc.