Regulation of gene expression in chronic lymphocytic leukemia cells in response to arsenic trioxide.

Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of malignant CD5+ B lymphocytes (CLL cells) in the peripheral blood, and their progressive infiltration in lymphoid organs. Despite the efforts made, CLL remains an incurable disease. It is therefore crucial to continue searching for new therapeutic agents and targets. Arsenic trioxide (ATO) induces apoptosis in all CLL cases and it could constitute an efficient therapy for this disease. We used Affimetrix microarray technology to characterize the global gene expression profile underlying CLL cell response to ATO, with the aim of identifying the ATO mechanism of action as well as new therapeutic targets in CLL. MEC-1 cells (CLL-derived) were incubated with or without 5 µM ATO for 24 h and total RNA was extracted and used to hybridize an Affymetrix GeneChip® Human Gene 1.0 ST Array.