Article |
Laboratory of Experimental Hematology, Faculty of Medicine, Institut Jules Bordet, Université Libre de Bruxelles (ULB), Brussels, Belgium
Correspondence: Basile Stamatopoulos, Université Libre de Bruxelles, Institut Jules Bordet, Laboratoire d'Hématologie Expérimentale, Boulevard de Waterloo n° 121, 1000 Bruxelles, Belgium. Phone: international +32(0)2.5413722. Fax: international +32 (0)2.5413453. E-mail: bstamato{at}ulb.ac.be
ABSTRACT
Background: Chronic lymphocytic leukemia (CLL) is a neoplastic disorder that arises largely as a result of defective apoptosis leading to chemoresistance. Furthermore, SDF-1 and its receptor CXCR4 have been shown to play an important role in CLL cell trafficking and survival.
Design and Methods: Since histone acetylation is involved in the modulation of gene expression, we evaluated the effects of suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, on CLL cells and in particular on cell survival, CXCR4 expression, migration, and drug sensitization.
Results: Here, we showed that a 48-hour treatment of SAHA (20 µM) induced a decrease in CLL cell viability via apoptosis (n=20, p=0.0032). Using specific caspase inhibitors, we demonstrated the participation of caspases-3, -6 and -8, suggesting an activation of the extrinsic pathway. Additionally, SAHA significantly decreased CXCR4 mRNA (n=10, p=0.0010) and protein expression (n=40, p<0.0001). As a result, CLL cell migration in response to SDF-1 (n=23, p<0.0001) or through bone marrow stromal cells was dramatically impaired. Consequently, SAHA reduced the protective effect of microenvironment and thus sensitized CLL cells to chemotherapy such as fludarabine.
Conclusions: In conclusion, SAHA induces apoptosis in CLL cells via the extrinsic pathway and downregulates CXCR4 expression leading to decreased cell migration. SAHA in combination with other drugs represents a promising therapeutic approach to inhibiting migration, CLL cell survival and potentially overcoming drug resistance.
Key words: SAHA, chronic lymphocytic leukemia, CXCR4, migration.