Abstract
Targeting tumor vasculature represents a rational strategy for controlling cancer. (Z)-(+/-)-2-(1-benzylindol-3-ylmethylene)-1-azabicyclo[2.2.2]octan-3-ol (denoted VJ115) is a novel chemical entity that inhibits the enzyme ENOX1, a NADH oxidase. Genetic and small molecule inhibition of ENOX1 inhibits endothelial cell tubule formation and tumor-mediated neo-angiogenesis. Inhibition of ENOX1 radiosensitizes tumor vasculature, a consequence of enhanced apoptosis. However, the molecular mechanisms underlying these observations are not well understood. Herein, we mechanistically link ENOX1-mediated regulation of cellular NADH concentrations with proteomics profiling of endothelial cell protein expression following exposure to VJ115. Pathway Studios network analysis of potential effector molecules identified by the proteomics profiling indicated that a VJ115 exposure capable of altering intracellular NADH concentrations impacted proteins involved in cytoskeletal reorganization. The analysis was validated using RT-PCR and immunoblotting of selected proteins. RNAi knockdown of ENOX1 was shown to suppress expression of stathmin and lamin A/C, proteins identified by the proteomics analysis to be suppressed upon VJ115 exposure. These data support the hypothesis that VJ115 inhibition of ENOX1 can impact expression of proteins involved in cytoskeletal reorganization and support a hypothesis in which ENOX1 activity links elevated cellular NADH concentrations with cytoskeletal reorganization and angiogenesis.