Effect of Lin28a overexpression on the PI3K/Akt/mTOR pathway. INS-1 cells were incubated with Ad-Lin28a or Ad-GFP at a MOI of 20 and then incubated with high glucose (HG, 30 mM D-glucose) for 48 h. Cells were treated with wortmannin, PI3K inhibitor, for 1 h before harvest (right panel). Western blot analysis for Lin28a, p-Akt, t-Akt, p-mTOR and t-mTOR. Quantification of western blots are from three independent experiments (bottom panel) and values are expressed as the mean ± SEM. *P value < 0.01 vs. NG/Ad-GFP. **P value < 0.001 and #P value < 0.01 vs. HG/Ad-GFP.