Epigenetic regulation in myelodysplastic syndromes: implications for therapy.

INTRODUCTION: Myelodysplastic syndromes (MDS), characterized by ineffective hematopoiesis and dysplasia in one or more lineages, produce life-threatening cytopenias and progress to acute myeloid leukemia (AML). Growing evidence suggests that targeting epigenetic mechanisms improves MDS/AML pathophysiology. AREAS COVERED: This review provides an understanding of studies investigating novel agents published up to January 2011 aimed at normalizing and monitoring the epigenetic profile of the MDS cancer cell. The authors discuss how non-intensive epigenetic therapy can 're-programme' gene expression patterns of abnormal hematopoiesis in MDS. Recently FDA-approved DNA-methyltransferase inhibitors, 5-azacytidine and 5-aza-2'-deoxycytidine or decitabine, represent frontline nonablative treatments, while combinations with histone deacetylase inhibitors show promising synergism in preclinical and Phase I/II trials in tumor suppressor gene re-expression and overall survival. Additional epigenetic mechanisms including non-encoding transcripts with inhibitory posttranscriptional regulatory functions, such as microRNAs, though not fully understood, present novel molecular and clinical implications in these disorders. EXPERT OPINION: Alongside current single-agent epigenetic regimens, combination therapies represent potentially effective options for intermediate-2 and high-risk MDS. Methylation profiles and gene mutation predictors provide promising areas of development for monitoring MDS disease progression and outcome, while targeting microRNA dysregulation represents an important therapeutic goal.

Lenalidomide in the treatment of chronic lymphocytic leukemia.

INTRODUCTION: insights into the role of the tumor microenvironment and of immune dysfunction in chronic lymphocytic leukemia (CLL) have opened the way for further augmenting the therapeutic armamentarium for CLL patients. In this respect, lenalidomide represents an exciting drug since it is able to eliminate CLL cells without immunosuppression. AREAS COVERED: mechanism of action and clinical trials of lenalidomide in CLL, and suggestions for its future utilization are reviewed. The most relevant papers and the meeting abstracts published up to July 2010 were used as sources for this review. This review will help readers understand the mechanism of action of lenalidomide and will provide a comprehensive summary regarding efficacy and safety of this drug in CLL patients. EXPERT OPINION: lenalidomide shows good activity against CLL. However, the toxicity profile is significant and can result in serious and potentially life-threatening side effects. Definitive data from ongoing trials will aid better definition of its status in CLL therapy. Moreover, clarification of the exact mechanism(s) of action in CLL will allow more precise use of lenalidomide and design of more efficacious combination therapies.

Janus kinase 2 inhibitors in myeloproliferative disorders.

IMPORTANCE OF THE FIELD: JAK2 is an obligatory kinase for the proliferation and differentiation of erythroid cells and megakaryocytes thus representing a relevant therapeutic target for agents that specifically inhibit its activity particularly in myeloproliferative disorders (MPD) harboring JAK2(V617F) mutations. AREAS COVERED IN THIS REVIEW: We discuss the physiopathology of the JAK2 signaling pathway and review clinical trials of JAK2 inhibitors for the treatment of MPD using papers and meeting abstracts published up to September 2010. WHAT THE READER WILL GAIN: This review helps in understanding the potential role of JAK2 inhibitors in MPD clinical trials and provides a comprehensive review regarding their efficacy and safety in these disorders. TAKE HOME MESSAGE: JAK2 inhibitors may prove to be useful only for suppressing disease manifestations. However, unlike drugs such as IFN which are capable of eliminating the malignant clone, JAK2 inhibitors are unable to eradicate the disease. In fact, results to date indicate that although these inhibitors reduce splenomegaly and alleviate constitutional symptoms irrespective of JAK2 mutational status, most have only a modest impact on the JAK2(V617F) allele burden. Considering the relevant risk of serious complications in patients undergoing splenectomy, these drugs could find a suitable indication in patients with myelofibrosis awaiting bone marrow transplantation.

Clinical, genetic and magnetic resonance findings in an Italian patient affected by L-2-hydroxyglutaric aciduria.

L-2-Hydroxyglutaric aciduria (L-2-HGA) is a neurometabolic disease characterized by the presence of elevated levels of 2-hydroxyglutaric acid in the plasma, cerebrospinal fluid and urine. Clinical features in this inherited condition consist of mental deterioration, ataxia and motor deficits with pyramidal and extrapyramidal symptoms and signs. L-2-HGA is caused by mutations in the L-2-HGDH gene which most probably encodes for a L-2-hydroxyglutarate dehydrogenase, a putative mitochondrial protein converting L-2-hydroxyglutarate to alphaketoglutarate. Here, we report a pathogenic nonsense mutation in the L-2-HGDH gene found for the first time in an Italian patient affected by L-2-HGA, reinforcing the previously described phenotype of this rare metabolic disease and confirming the data indicating that mutations in the L-2-HGDH gene cause L-2-HGA.