7-nitro-10-octyl-3-phenyl-pyrimido[4,5-b]quinoline-2,4(3H,10H)-dione

7-nitro-10-octyl-3-phenyl-pyrimido[4,5-b]quinoline-2,4(3H,10H)-dione is an antagonist of the interaction between survivin and the apoptosis-promoting protein Smac/Diablo, exhibiting an IC₅₀ value of 2.2 µM. It inhibits the interaction of survivin with INCENP less effectively with an IC₅₀ value of 20 μM. Survivin is a cellular protein implicated in cell survival by interacting with and inhibiting the apoptotic function of several proteins including Smac/Diablo, caspase-3, and caspase-7. Survivin also plays a role in the regulation of the cell cycle as part of a protein complex that includes INCENP, Aurora B kinase, and Borealin. 7-nitro-10-octyl-3-phenyl-pyrimido[4,5-b]quinoline-2,4(3H,10H)-dione is cell-permeable and sensitizes cells to the induction of apoptosis by doxorubicin.