Figure 5

Analysis of components of the G2 block. Western blot of CD44^high and CD44^low fractions showing low baseline levels of phosphorylated Chk1 and Chk2 in the unstimulated Cal cell line (A). After 24 hours of exposure to 100 ng/ml NCZ levels increase, especially for CD44^high cells (A). Cells of the Ca1 cell line before and after inhibition of Chk1/2 with DBH show increased cell death associated with partial release from the G2 block (p < 0.01) (B). Rates of cell death and proportion of CD44^high cells after independent knockdown with siRNAs of Chk1 and Chk2 in CaLH3 cells show an effect mainly via Chk1 (C). Message levels for Wee1 and Myt1 in CD44^high and CD44^low cells of the Ca1 cell line. The CD44^high cells of both cell types show higher levels of Myt1 and CD44^high Ca1 cells higher levels of Wee1 (D).