AIF/XIAP Axis in Prostate Cancer

摘要

In the past year we have progressed substantially towards completion of our project goals. We have redesigned our lentiviral protocol for restoration of AIF protein expression (and variants thereof) in shAIF ablated PC3 cells. This has allowed the construction of a panel of PC3-derived cells lines that either overexpress AIF variants (wildtype or enzymatically inactive TVA) or express these variants in the absence of endogenous AIF protein. This panel of cells was subjected to 3 dimensional culture experiments, which indicated that whereas suppression of AIF in these cells abrogated 3 dimensional growth, restoration of expression with wildtype AIF, but not the TVA variant, was critical to supporting normal growth in 3 dimensional cultures. Molecular analysis of these cells indicated that AIF suppression led to a decrease in the expression of complex I of the mitochondrial electron transport chain, and that either wildtype or TVA-AIF could restore this expression. Interestingly, despite normal complex I levels, TVA expressing cells exhibited high levels of glycolysis, similar to AIF deficient cells, suggesting that the glycolytic switch observed upon AIF ablation is related to enzymatic activity of the protein. Overall these data show for the first time that the ability of AIF to support prostate cancer cell growth is dependant upon the enzymatic activity of the protein.