Figure 3. L1CAM expression in normal and tumor senescent cells depends on the cell type and senescence-inducing stimulus. Normal (MRC5, HSF), immortalized (RPE-1) and tumor (PANC-1, PC3, A375, U2OS, and DU145) cells were brought to senescence either by BrdU (10 μM for A375, 100 μM for rest of cell types) or IR (10 Gy) and assayed for cell surface L1CAM protein expression by live cell immunostaining with L1CAM antibodies. (A) L1CAM mRNA expression by real time RT-qPCR quantification (B) and total L1CAM protein level by immunoblotting (C). GAPDH was used as a reference gene; β-actin was used as a loading control. The values representing two independent experiments are shown as a fold induction relative to control. N.D., not detected. Scale bar, 50 μm.