Histone code-breakers: the technologies of an epigenetic enigma

Hitchhiker antigens: Inconsistent ChIP results, questionable immunohistology data, and poor antibody performance may have a common factor

Questionable data and poor antibody performance may have a common factor: antigens “hitchhiking” on the very antibodies designed to target them. Here I focus on histone hitchhikers and their antibodies, given the impact of chromatin immunoprecipitation on our understanding of DNA regulation. Caused by a lack of stringency during antibody purification, hitchhikers will impede important advances in chromatin research and therapeutics derived from that research, if similar circumstances in the study of lupus decades ago are any guide. Evidence of this phenomenon is reviewed, purification modifications for antibody manufacturing are suggested, and a histone hitchhiker detection procedure is provided.

Butyrate histone deacetylase inhibitors

In addition to being a part of the metabolic fatty acid fuel cycle, butyrate is also capable of inducing growth arrest in a variety of normal cell types and senescence-like phenotypes in gynecological cancer cells, inhibiting DNA synthesis and cell growth in colonic tumor cell lines, suppressing hTERT mRNA expression and telomerase activity in human prostate cancer cells, and inducing stem cell differentiation and apoptosis by DNA fragmentation. It regulates gene expression by inhibiting histone deacetylases (HDACs), enhances memory recovery and formation in mice, stimulates neurogenesis in the ischemic brain, promotes osteoblast formation, selectively blocks cell replication in transformed cells (compared to healthy cells), and can prevent and treat diet-induced obesity and insulin resistance in mouse models of obesity, as well as stimulate fetal hemoglobin expression in individuals with hematologic diseases such as the thalassemias and sickle-cell disease, in addition to a multitude of other biochemical effects in vivo. However, efforts to exploit the potential of butyrate in the clinical treatment of cancer and other medical disorders are thwarted by its poor pharmacological properties (short half-life and first-pass hepatic clearance) and the multigram doses needed to achieve therapeutic concentrations in vivo. Herein, we review some of the methods used to overcome these difficulties with an emphasis on HDAC inhibition.