The kinase Akt (also known as protein kinase B or PKB) modulates cell proliferation, metabolism, and survival, as well as angiogenesis. Akt inhibitor XI is a cell-permeable, copper-containing 3-formylchromone derivative that inhibits Akt in an array of cancer cells (IC50s = 10-34 μM). It also causes NF-κB inactivation in an orthotopic pancreatic tumor model using COLO 357 cells. Molecular modeling indicates that this inhibitor interacts with the pleckstrin homology and kinase domains of Akt. Akt inhibitor XI is commonly used in the range of 1-20 μM to assess the role of Akt in cellular responses.