Depressed p34cdc2 kinase activity and G2/M phase arrest induced by diallyl disulfide in HCT-15 cells.

The present studies reveal the antiproliferative property of diallyl disulfide (DADS) in cultured human colon tumor cells (HCT-15) relative to its ability to decrease the proportion of cells in the G1 phase and increase the proportion of cells in the G2/M phase. The shift in the proportion of cells blocked in the G2/M phase increased as the concentration and duration of DADS exposure increased. Refeeding DADS-treated cells (50 microM) with complete medium without DADS resulted in a return to normal proliferation rates. Consistent with the G2/M phase arrest, DADS exposure inhibited p34cdc2 kinase activity within four hours of treatment. The maximum depression in p34cdc2 kinase activity (53%) occurred when 25 microM DADS was added to the medium. The present studies suggest that depressed p34cdc2 kinase activity is likely one of the early cellular events that may account for the antiproliferative property of DADS.