Figure 5.

p21^Cip1 and p27^Kip1 abundance after CPT exposure or nutrient restriction in GSC-ECLs. (A) Analysis of p21^Cip1and p27^Kip1 mRNA expression levels by real-time RT-PCR in GSC-ECLs after CPT treatment or nutrient restriction over a 24- or 48-hour period. RPL7 expression was used as normalizer. Graphs show mRNA fold change relative to untreated control cells, arbitrarily set as 1. Bars represent the mean ± S.E.M. of three different experiments performed in triplicate. Student's t test was used to compare CPT- or NR-treated to untreated samples (*P ˂ .05, **P < .01, ***P < .001). (B) Western blot analysis of GSC-ECLs under control conditions and after 48 hours of CPT exposure or nutrient restriction. Antibodies against p21^Cip1, p27^Kip1, and actin (loading control) were used.