Figure 2. L1CAM expression in premature senescence induced by various stimuli. BJ fibroblasts were brought to premature senescence by γ-irradiation (PD 32, IR 20 Gy), 100 μM 5-bromo-2'-deoxyuridine (PD 32, BrdU), 500 U/ml IFNγ (PD35), or by induction of oncogenic HRAS using the Tet on system (see Materials and Methods). Cell surface expression of L1CAM estimated by live cell immunostaining with L1CAM antibody was detected microscopically (A) or (B) by FACS. The values representing three independent experiments are shown as a fold induction relative to control. (C) Real time RT-qPCR quantification of mRNA levels of L1CAM in BJ cells brought to premature senescence as in A. The values representing three independent experiments are shown as a fold induction relative to control. GAPDH was used as a reference gene. For statistics, two-tailed Student’s t-test was used; p ˂ 0.05 (*); p ˂ 0.01 (**); p ˂ 0.001 (***). Scale bar, 50 μm.