The study on the role of different isoforms of Akt in the regulation of apoptosis

Objective To study the molecular mechanism of phosphatidylinositol 3-kinase (PI3K)/Akt active pathway that involve in the regulation of apoptosis. Methods Different tumor cells were seeded into either 96 well or 6 well tissue culture plates and incubated with isoform specific Akt inhibitor for 6 hours. Akt phosphorylation and its activity were evaluated with immunoprecipitation; the activation of phosphorylated Akt were detected by immunoprecipitation and western blotting; Caspase assay has been performed to quantitate apoptosis. Results ①The inhibitors could reduce the phosphorylations of threonine 308 and serine 473 of isoform specific Akt ;②the inhibition of any isoform specific Akt could significantly downregulate the activation and activity of its substrate(GSK3) , but it was not the same case if blocking two isoforms of both Akt1 and Akt2 at the same time;③ PI3K involves in the regulation of apoptosis mainly through its downstream gene(AKT) , specifically the isoforms of Aktl and Akt2. Conclusion PI3K/Akt involves in the regulation of apoptosis, two isoforms of Akt(Akt1 and Akt2) are mainly the regulator of PI3K in terms of the regulation of apoptosis. It is required to inhibit two isoforms of both Akt1 and Akt2 to initiate apoptosis.