Histone deacetylase inhibitors for the treatment of cancer stem cells

Tiny populations of tumor cells are present in solid and hematologic malignancies and are responsible for cancer development, metastasis and limited response to therapy; these are referred to as cancer stem cells (CSCs). CSCs are resistant to standard cancer treatments and are the main cause of tumor relapse. Therefore, the development of new therapeutics to overcome the resistance of CSCs is greatly required. It is known that epigenetic histone modifications (acetylation/deacetylation) play a crucial role in cancer development through regulation of gene expression. Deacetylation of histone and non-histone proteins controls cell proliferation, metabolism and apoptosis as well as DNA repair and differentiation. Thus, histone deacetylase inhibitors (HDACis) are a promising group of anti-cancer agents, showing the ability to induce growth arrest or apoptosis in tumor cells. In this review, we summarize the current knowledge about the prospects of HDACis utilization in the treatment of CSCs.