LEF-1 is a prosurvival factor in chronic lymphocytic leukemia and is expressed in the preleukemic state of monoclonal B-cell lymphocytosis

• Published in: Blood Vol. 116; no. 16; pp. 2975 - 2983
• Main Authors: Gutierrez, Albert, Tschumper, Renee C., Wu, Xiaosheng, Shanafelt, Tait D., Eckel-Passow, Jeanette, Huddleston, Paul M., Slager, Susan L., Kay, Neil E., Jelinek, Diane F.
• Format: Journal Article
• Language: English
• Published: Washington, DC Elsevier Inc 21.10.2010; Americain Society of Hematology; American Society of Hematology
• Series: Lymphoid Neoplasia
• Subjects: Adult; Aged; Aged, 80 and over; B-Lymphocyte Subsets - cytology; B-Lymphocyte Subsets - metabolism; B-Lymphocytes - cytology; B-Lymphocytes - metabolism; B-Lymphocytes - pathology; Biological and medical sciences; Cell Survival; Female; Gene Expression Regulation, Leukemic; Hematologic and hematopoietic diseases; Humans; Leukemia, Lymphocytic, Chronic, B-Cell - genetics; Leukemia, Lymphocytic, Chronic, B-Cell - metabolism; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Lymphoid Enhancer-Binding Factor 1 - genetics; Lymphoid Enhancer-Binding Factor 1 - metabolism; Lymphoid Neoplasia; Male; Medical sciences; Middle Aged; Precursor Cells, B-Lymphoid - cytology; Precursor Cells, B-Lymphoid - metabolism; Precursor Cells, B-Lymphoid - pathology; Wnt Proteins - genetics; Chronic lymphocytic leukemia; Hematology; Lymphoproliferative syndrome; Malignant hemopathy; B-Lymphocyte; Lymphocytosis; Cancer
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2010-02-269878

The canonical Wnt signaling pathway is pathogenic in a variety of cancers. We previously identified aberrant expression of the Wnt pathway transcription factor and target gene lymphoid enhancer binding factor-1 (LEF1) in chronic lymphocytic leukemia (CLL). This suggested that the Wnt signaling pathway has a role in the biology of CLL. In this study, we performed a Wnt pathway analysis using gene expression profiling and identified aberrant regulation of Wnt pathway target genes, ligands, and signaling members in CLL cells. Furthermore, we identified aberrant protein expression of LEF-1 specifically in CLL but not in normal mature B-cell subsets or after B-cell activation. Using the T cell–specific transcription factor/LEF (TCF/LEF) dual luciferase reporter assay, we demonstrated constitutive Wnt pathway activation in CLL, although the pathway was inactive in normal peripheral B cells. Importantly, LEF-1 knockdown decreased CLL B-cell survival. We also identified LEF-1 expression in CD19+/CD5+ cells obtained from patients with monoclonal B-cell lymphocytosis, suggesting a role for LEF-1 early in CLL leukemogenesis. This study has identified the constitutive activation and prosurvival function of LEF-1 and the Wnt pathway in CLL and uncovered a possible role for these factors in the preleukemic state of monoclonal B-cell lymphocytosis.