Antileukemic activity of valproic acid in chronic lymphocytic leukemia cells defined by microarray analysis

Epigenetic code modifications by histone deacetylase inhibitors (HDACi) have recently been proposed as potential new therapies for hematological malignancies. Chronic Lymphocytic Leukemia (CLL) remains incurable despite the introduction of new treatments. CLL cells are characterized by an apoptosis defect rather than excessive proliferation, but proliferation centers have been found in organs such as bone marrow and lymph nodes. Here, we investigated gene expression modifications in CLL cells following treatment with valproic acid (VPA), a well-tolerated anti-epileptic drug with HDAC inhibitory activity. CLL cells obtained from 14 patients were treated in vitro with a concentration of 1mM VPA for 4 hours. VPA effects on gene expression were thereafter studied using Affymetrix technology