The nuclear factor κB inhibitor (E)-2-fluoro-4'-methoxystilbene inhibits firefly luciferase.

Photinus pyralis (firefly) luciferase is widely used as a reporter system to monitor alterations in gene promoter and/or signalling pathway activities in vitro. The enzyme catalyses the formation of oxyluciferin from D-luciferin in an ATP-consuming reaction involving photon emission. The purpose of the present study was to characterize the luciferase-inhibiting potential of (E)-2-fluoro-4'-methoxystilbene, which is known as a potent inhibitor of the NF-κB (nuclear factor κB) signalling pathway that is used to modulate the NF-κB signalling pathway in vitro. Results show that (E)-2-fluoro-4'-methoxystilbene effectively inhibits firefly luciferase activity in cell lysates and living cells in a non-competitive manner with respect to the luciferase substrates D-luciferin and ATP. By contrast, the compound has no effect on Renilla and Gaussia luciferases. The mechanism of firefly luciferase inhibition by (E)-2-fluoro-4'-methoxystilbene, as well as its potency is comparable to its structure analogue resveratrol. The in vitro use of trans-stilbenes such as (E)-2-fluoro-4'-methoxystilbene or resveratrol compromises firefly luciferase reporter assays as well as ATP/luciferase-based cell viability assays.