Targeting histone deacetylase in thyroid cancer

Epigenetic changes have been detected in thyroid cancer cells, and evidence indicates that they may contribute to altered differentiation and proliferation of these cells. Histone acetylation/deacetylation represents a major mechanism for modulating the expression of genes, including those involved in neoplastic transformation, and drugs that inhibit histone deacetylase (HDAC) activity have displayed promising anti-tumor activity in many pre-clinical studies.We provide a brief overview of the mechanisms underlying histone acetylation-mediated regulation of gene expression and the principal epigenetic alterations detected in thyroid cancer cells. The review then focuses on the results of pre-clinical and clinical studies (some still underway) in which HDAC inhibitors (HDACi) have been used to treat thyroid cancer.HDACs are a potentially important target for thyroid cancer treatments. Inhibition of HDAC activity has produced encouraging results in terms of reducing proliferation rates and restoring the iodine-uptake capacity in transformed thyrocytes. HDACi, especially when combined with other molecularly targeted drugs, may represent an important option for those tumors that are unresponsive to the currently available treatments.