Figure 3.

Escape from senescence increased the viability and decreased the apoptosis rate of TMZ-treated U251 cells. A: Cell viability as detected by the trypan blue exclusion assay. The relative cell numbers in two subclones of senescence-escaping U251 cells were higher than those in senescent U251 cells. B and C: Representative images and results of a quantitative analysis of cell cycle distribution. Escape from senescence induced a higher proportion of G0/G1 and S phase cells. D: Representative images and results of a quantitative analysis of apoptosis. Apoptosis was suppressed in senescence-escaping cells. E: Representative images of Hoechst staining results. Smaller numbers of Hoechst-positive cells (bright blue) were recorded among senescence-escaping cells. “*”, significant difference between groups, P<0.05.