Overexpression of FoxO1 induces apoptosis in MGCs. MGCs were transfected with plasmids encoding wild-type FoxO1 (W), a constitutively active FoxO1 mutant (A), and a non-transfection control (C), respectively. A, overexpression of FoxO1 (W) promoted apoptosis in cultured MGCs. Apoptosis images were visualized with propidium iodide/annexin V-FITC staining (bar, 100 μm). B, overexpression of FoxO1 induced a nuclear accumulation of FoxO1 protein. Immunofluorescence was performed using anti-FoxO1 (red), and the nuclei were counterstained with DAPI (blue). Bar, 100 μm. C, overexpression of FoxO1 increased mRNA levels of apoptosis-related genes. Quantitative RT-PCR was applied to measure the corresponding mRNA levels. The relative expression data were normalized to the amount of cellular β-actin. The corresponding data above represent mean ± S.E. (error bars) (n = 3). The statistical significance between groups was analyzed by one-way ANOVA. *, p < 0.05; **, p < 0.01.