The triphenylethylenes, a novel class of antifungals.

ABSTRACT New antifungals are needed, particularly in the developing world, to treat life-threatening fungal infections, such as cryptococcosis. Drug repurposing is one strategy to identify new drug-like compounds, but it is often difficult to identify a mechanism of action. Here we discuss the outstanding effort by Butts et al. to identify calmodulin as an antifungal target of repurposed estrogen receptor antagonists [A. Butts, K. Koselny, Y. Chabrier-Roselló, C. P. Semighini, Y. C. S. Brown, et al., mBio 5(1):e00765-13, 2014, doi:10.1128/mBio.00765-13]. The authors show that these compounds bind to and directly inhibit fungal calmodulin and also reduce fungal burden in an animal disease model. These studies thus establish both the key preclinical efficacy and the antifungal mechanism of action, which will allow these compounds to progress toward development of novel antifungal therapies.