Abstract: Objective To investigate the effect of protein kinase B and its phosphorylation on apoptosis of MIN6 induced by palmitate. Methods Incubated with different levels of palmitate concentration (0~0.5mmol/L), MIN6 cells were cultured in high glucose DMEM with or without LY294002; the apoptosis of MIN6 cells was detected and quantified with TUNEL technology. Then we inspected the cell ultrastructure under an electron microscope and determined the expression of protein kinase B and its phosphorylation p-PKB (ser473) by Western blotting, followed by an RT-PCR detection of BAX and BCL-2 expression. Results Apoptosis of MIN6 cells were induced by palmitate in a concentration-dependent correlation and enhanced by ly294002. Palmitate also inhibited phosphorylation of protein kinase B on ser473. Finally, we detected a downregulation of BCL-2 mRNA expression and upregulation of BAX mRNA expression under palmitate-incubated state. Conclusion Palmitate may induce apoptosis of pancreatic β-cells through inhibiting activation of PKB phosphorylation in diabetes.

Key words: lipotoxicity, protein kinase B, BCL-2, BAX, MIN-6 cells, apoptosis