Romidepsin: evidence for its potential use to manage previously treated cutaneous T cell lymphoma

A short guide to histone deacetylases including recent progress on class II enzymes

The interaction between histones and DNA is important for eukaryotic gene expression. A loose interaction caused, for example, by the neutralization of a positive charge on the histone surface by acetylation, induces a less compact chromatin structure, resulting in feasible accessibility of RNA polymerase and increased gene expression. In contrast, the formation of a tight chromatin structure due to the deacetylation of histone lysine residues on the surface by histone deacetylases enforces the interaction between the histones and DNA, which minimizes the chance of RNA polymerases contacting DNA, resulting in decreased gene expression. Therefore, the balance of the acetylation of histones mediated by histone acetylases (HATs) and histone deacetylases (HDACs) is an issue of transcription that has long been studied in relation to posttranslational modification. In this review, current knowledge of HDACs is briefly described with an emphasis on recent progress in research on HDACs, especially on class IIa HDACs.

Targeting specific structural and functional features of enzymes involved in regulating the interactions between DNA and the histone proteins associated with it could lead to the development of more effective cancer therapeutics. Histone deacetylases (HDACs), enzymes which remove acetyl groups from histones, make the histones wrap more tightly around the DNA so that it becomes inaccessible to the initial steps in gene expression. Drugs that target these enzymes have shown limited efficacy due to lack of specificity and off-target toxicity. Jeong-Sun Kim at Chonnam National University, Gwangju, and Suk-Youl Park at Pohang Accelerator Laboratory, Pohang University of Science and Technology, South Korea, review the latest knowledge about class II HDACs. They suggest that their unique structural features and low enzymatic activity are important features to consider when designing new, more selective HDAC inhibitors.

Cutaneous T-cell lymphomas: modern data of pathogenesis, clinics and therapy

Cutaneous T-cell lymphomas (CTCL) are a heterogeneous group of extranodal non-Hodgkin’s lymphomas that are characterized by skin infiltration with malignant monoclonal T lymphocytes. More common in adults aged 55 to 60 years, the annual incidence is about 0.5 per 100 000 people. Mycosis fungoides, Sézary syndrome and CD30+ lymphoproliferative diseases are the main subtypes of CTCL. To date, CTCL have a complex concept of etiopathogenesis, diagnosis, therapy and prognosis. The article presented summary data on these issues.

Current and Emerging Therapeutics for Cutaneous T-Cell Lymphoma: Histone Deacetylase Inhibitors

Cutaneous T-cell lymphoma is a term that encompasses a spectrum of non-Hodgkin’s T-cell lymphomas with primary manifestations in the skin. It describes a heterogeneous group of neoplasms that are characterised by an accumulation of malignant T cells of the CD4 phenotype that have the propensity to home and accumulate in the skin, lymph nodes, and peripheral blood. The two most common variants of cutaneous T-cell lymphoma include mycosis fungoides and the leukemic variant, the Sézary syndrome. While numerous treatments are available for cutaneous T-cell lymphoma and have shown to have success in those with patch and plaque lesions, for those patients with tumour stage or lymph node involvement there is a significant decline in response. The relatively new therapeutic option with the use of histone deacetylase inhibitors is being advanced in the hope of decreasing morbidity and mortality associated with the disease. Histone deacetylase inhibitors have been shown to induce changes in gene expression, affecting cell cycle regulation, differentiation, and apoptosis. The aim of this paper is to discuss CTCL in the context of advances in CTCL treatment, specifically with HDAC inhibitors.