Alterations of lymphoid enhancer factor-1 isoform expression in solid tumors and acute leukemias.
Two major transcripts of lymphoid enhancer factor-1 (LEF-1) have been described. The long isoform with b-catenin binding domain functions as a transcriptional enhancer factor. The short isoform derives from an intronic promoter and exhibits dominant negative activity. Recently, alterations of LEF-1 isoforms distribution have been described in colon cancer. In the current study we employed a quantitative real-time reverse transcription PCR method (TaqMan) to analyze expression of LEF-1 isoforms in a large cohort of human tumor (n = 304) and tumor-free control samples (n = 56). The highest expression level of LEF-1 was found in carcinoma samples whereas brain cancer samples expressed little. Expression of LEF-1 was different in distinct cancer types. For example, the mRNA level of LEF-1 was lower in testicular tumor samples compared with tumor-free control samples. Besides epithelial cancers, significant LEF-1 expression was also found in hematopoietic cells. In hematological malignancies, overall LEF-1 level was higher in lymphocytic leukemias compared with myeloid leukemias and normal hematopoiesis. However, acute myeloid leukemia and acute lymphocytic leukemia showed a significantly increased fraction of the oncogenic LEF-1 compared with chronic lymphocytic leukemia and chronic myeloid leukemia. Taken together, these data suggest that LEF-1 is abundantly expressed in human tumors and the ratio of the oncogenic and the dominant negative short isoform altered not only in carcinomas but also in leukemia.
Wang
Wenbing
W
Institute of Life Sciences, Jiangsu University, Zhenjiang, China.
Ji
Ping
P
Steffen
Björn
B
Metzger
Ralf
R
Schneider
Paul M
PM
Halfter
Hartmut
H
Schrader
Mark
M
Berdel
Wolfgang E
WE
Serve
Hubert
H
Müller-Tidow
Carsten
C
D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007938:Leukemia / Q000235:genetics / Q000378:metabolism; D051821:Lymphoid Enhancer-Binding Factor 1; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; C497573:LEF1 protein, human; D051821:Lymphoid Enhancer-Binding Factor 1; D009363:Neoplasm Proteins; D020033:Protein Isoforms; D014157:Transcription Factors