The suppression of anoikis in HEK293ar mediated by cell-cell contacts involves the PI3K/Akt pathway. A. The effect of the PI3K (phosphoinositide 3-kinase) inhibitor LY294002 (20, 50 μmol/l) or the ERK (extracellular signal-regulated kinase) inhibitor PD98059 (20, 50 μmol/l) on cell-cell contacts formation (n = 4-10). Magnification: × 200. B. The effect of signal pathway inhibitors treatment on the degree of cell aggregation (n = 4-10). The cells were counted in 4-10 independent sections (at least 300 nuclei/section). C. The effect of signal pathway inhibition on the survival of cells in suspension. The anoikis was determined with TUNEL assay kit. The apoptotic nuclei were counted in 4-10 independent sections (at least 500 nuclei/section). The concentration of both LY294002 (PI3K inhibitor) and PD98059 (ERK inhibitor) is 50 μmol/l. Magnification: ×200. D. The effect of signal pathway inhibitors LY294002 (0, 20, 50 μmol/l) or PD98059 (0, 20, 50 μmol/l) on cell number. It was evaluated with a CyQUANT® NF Cell Proliferation Assay Kit (C35006, Invitrogen, Ltd) according to the manufacturer's protocol for the nonadherent cells. ** p < 0.01, LY294002 (20) versus LY294002 (50). Newman-Keuls Multiple Comparison Test. Each value represents the mean ± SD of at least triplicate determinations. Results are the representative of three similar experiments.