Figure 4

Akt activation is essential for acid and leptin stimulated proliferation of oesophageal cancer cells. Serum-starved OE33 cells were treated with a pH 4.0 acid or control pulse for three minutes and/or leptin (10 nM) for 24 hours and then relative cell numbers assessed by MTT assay (4a) or DNA synthesis by BrdU incorporation (4b). DNA synthesis in similarly treated OE19 cells was assessed by BrdU incorporation (4c). Where indicated cells were pretreated with the PI3-kinase inhibitor LY294002 (10 μM) for 60 minutes before any stimulation. Results are expressed as the percentage of value compared to untreated control cells on the same plate. * P < 0.05 vs untreated control, ** P < 0.05 vs acid or leptin alone, *** P < 0.05 vs stimulus in the absence of LY294004, N = 3–6, mean ± SEM.