Demecolcine (Colcemid), an inhibitor of spindle fiber formation in M p
hase, induced apoptosis in V79 cells. At a concentration of 0.01 mu g/
ml demecolcine, V79 cells proliferated exponentially as well as contro
ls, although temporal M phase accumulation occurred 6 h after the addi
tion of demecolcine. At 0.1 mu g/ml, the cells became hyperploid after
remaining in the M phase for some time. Apoptosis occurred in V79 cel
ls exposed to demecolcine at a concentration of 0.03 mu g/ml. Apoptosi
s was defined as the appearance of a sub-G1 peak in DNA histograms and
a ladder pattern of fragmented DNA in gelelectrophoresis.