First Author | Acquaviva J | Year | 2008 |
Journal | Blood | Volume | 112 |
Issue | 9 | Pages | 3798-806 |
PubMed ID | 18713947 | Mgi Jnum | J:142294 |
Mgi Id | MGI:3820819 | Doi | 10.1182/blood-2007-10-117838 |
Citation | Acquaviva J, et al. (2008) IRF-4 functions as a tumor suppressor in early B-cell development. Blood 112(9):3798-806 |
abstractText | Interferon regulatory factor-4 (IRF-4) is a hematopoietic cell-restricted transcription factor important for hematopoietic development and immune response regulation. It was also originally identified as the product of a proto-oncogene involved in chromosomal translocations in multiple myeloma. In contrast to its oncogenic function in late stages of B lymphopoiesis, expression of IRF-4 is down-regulated in certain myeloid and early B-lymphoid malignancies. In this study, we found that the IRF-4 protein levels are increased in lymphoblastic cells transformed by the BCR/ABL oncogene in response to BCR/ABL tyrosine kinase inhibitor imatinib. We further found that IRF-4 deficiency enhances BCR/ABL transformation of B-lymphoid progenitors in vitro and accelerates disease progression of BCR/ABL-induced acute B-lymphoblastic leukemia (B-ALL) in mice, whereas forced expression of IRF-4 potently suppresses BCR/ABL transformation of B-lymphoid progenitors in vitro and BCR/ABL-induced B-ALL in vivo. Further analysis showed that IRF-4 inhibits growth of BCR/ABL+ B lymphoblasts primarily through negative regulation of cell-cycle progression. These results demonstrate that IRF-4 functions as tumor suppressor in early B-cell development and may allow elucidation of new molecular pathways significant to the lymphoid leukemogenesis by BCR/ABL. The context dependent roles of IRF-4 in oncogenesis should be an important consideration in developing cancer therapies targeting IRF-4. |