4-PBA (Sodium Phenylbutyrate)

Phenylbutyrate is a well-known HDAC inhibitor, which increases gene transcription of a number of genes, and also exerts neuroprotective effects. Phenylbutyrate significantly attenuates MPTP-induced depletion of striatal dopamine and loss of tyrosine hydroxylase-positive neurons in the substantia nigra. ^[1]

Phenylbutyrate attenuates the expression of the apoptosis antagonist Bcl-X(L), the double-strand break repair protein DNA-dependent protein kinase, the prostate progression marker caveolin-1, and the pro-angiogenic vascular endothelial growth factor in prostate cancer cells. Phenylbutyrate is found to act in synergy with ionizing radiation to induce apoptosis in prostate cancer cells. ^[2]

Cells were treated with indicated concentration of drug for 24 h.

Phenylbutyrate significantly extends survival and improved both the clinical and neuropathological phenotypes in G93A transgenic ALS mice. Phenylbutyrate administration ameliorates histone hypoacetylation observed in G93A mice and induced expression of nuclear factor-kappaB (NF-kappaB) p50, the phosphorylated inhibitory subunit of NF-kappaB (pIkappaB) and beta cell lymphoma 2 (bcl-2), but reduced cytochrome c and caspase expression. Phenylbutyrate acts to phosphorylate IkappaB, translocating NF-kappaB p50 to the nucleus, or to directly acetylate NF-kappaB p50. ^[3]

Phenylbutyrate increases brain histone acetylation and decreased histone methylation levels as assessed by both immunocytochemistry and Western blots in a transgenic mousemodel of Huntington's disease (HD). Phenylbutyrate increases mRNA for components of the ubiquitin-proteosomal pathway and down-regulated caspases implicated in apoptotic cell death, and active caspase 3 immunoreactivity in the striatum. ^[4]