Two distinct inhibitors of PI3K suppress cell spreading mediated by <i>trans</i>-homophilic interaction of CADM1.

<p>(A) Cell spreading assay of MDCK+CADM1-GFP cells incubated on IgG or CADM1-EC-Fc in the presence of an inhibitor of PI3K, LY294002, from concentrations of 0.01 μM to 10 μM as indicated. *, p<0.05; NS, no significant difference (vs. cells on CADM1-EC-Fc with DMSO). (B) Cell spreading assay was performed using MDCK+CADM1-GFP cells cultured on CADM1-EC-Fc with 1 μM of LY294002 for 45 min and then washed and further incubated for 45 min in the presence of the same concentration of LY294002 (LY294002) or DMSO (LY294002+washout). Representative images of CADM1-GFP are shown at the top of each bar graph. The area was normalized to that of cells on IgG with DMSO, and the relative value of the cell surface area to that of cells on CADM1-EC-Fc with DMSO was shown. *, p<0.05. (A and B) The results presented are mean ± SD of three independent experiments. More than 200 and 280 cells were counted in A and B, respectively. (C) Aggregation assay of MDCK+CADM1-GFP cells in Ca²⁺- and Mg²⁺-free condition in the presence of LY294002 at the concentrations indicated. The cell aggregation was represented by the ratio of the total particle number at time <i>t</i> of incubation (Nt) to the initial particle number (N0). The data shown here indicate the average Nt/N0 in triplicate experiments.