(A) Expression of cyclins D1, D2, D3, E and cdk2 were measured using western blot and fluorescence signals were normalized to GAPDH as a loading control. For cyclin D1, the top band (open arrowhead) corresponds to the phosphorylated form of cyclin D1 and the bottom band (closed arrowhead) corresponds to the unphosphorylated form of cyclin D1. (B) Expression of total retinoblastoma protein (pRb) and associated pRb phosphorylation at different serine residues (S780, S795, and S807/811) was measured. The fluorescence signal for each band was normalized to GAPDH as a loading control. For pRb S795, normalization was also performed against total pRb. Quantitation of samples is shown as the average with SEM. Statistical analysis was applied using repeated measures one-way ANOVA with Bonferroni multiple comparisons post-hoc analysis (****p<0.0001, *** p<0.001, ** p<0.01 *p<0.5; n=3–5).