Sodium 4-phenylbutyrate is a chemical chaperone that has been shown to rescue the trafficking of misfolded proteins. It also weakly blocks histone deacetylase activity (IC50 = 0.4 mM), which results in cell cycle arrest, differentiation, and/or apoptosis of various tumors. Sodium 4-phenylbutyrate has been tested in clinical trials for the treatment of recurrent malignant gliomas and myelodysplastic syndrome and has long been used for treating urea cycle disorders.
