 SIRT1 reverses this acetylation process; however, the exact mechanism by which SIRT1 deacetylates FOXO1 is still under investigation; presently, acetylation is thought to mitigate the transcriptional activity of FOXO1 and thereby provide an additional level of metabolic regulation that is independent of the insulin/PI3K pathway.FOXO1 may play an important role in apoptosis because it is phosphorylated and inhibited by AKT.When FOXO1 over expressed in human LNCaP prostate cancer cells, it caused apoptosis in these cancer cells.