Fig. 2

Induction of lung epithelial cell apoptosis by the cell adhesion molecule 1 intracellular domain (C-ICD) peptide. NCI-H441 and RLE-6TN cells were treated with Xfect solutions containing the unlabeled C-ICD or the cell adhesion molecule 1 intracellular domain mutant (C-ICDmut) peptide or were left untreated (−). The cells were analyzed the next day by Western blotting using anti-cell adhesion molecule 1 (CADM1) antibody (a). Arrowheads indicate immunoreactive bands corresponding to full-length CADM1, the C-ICD. The blots were reprobed with anti-β-actin antibody to indicate protein loading. Another set of cells was analyzed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay (b). The mean proportions of TUNEL-positive cells (depicted by arrows) and standard errors are indicated under the panels. The P-values were determined by Student s t-test. Bar = 50 μm. c Similar TUNEL assays were done using the FITC-labeled C-ICD peptide (C-ICD-FITC). The mean proportions of TUNEL-positive cells and standard errors were calculated in each of FITC-positive and -negative cells. Cells double positive for FITC and TUNEL are depicted by arrowheads. The P-values were determined by Student’s t-test. Bar = 20 μm