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Exp Cell Res. 2011 Apr 15;317(7):920-31. doi: 10.1016/j.yexcr.2011.01.015. Epub 2011 Jan 20.

Identification of T-cell factor-4 isoforms that contribute to the malignant phenotype of hepatocellular carcinoma cells.

Author information

1
Liver Research Center, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI 02903, USA.

Abstract

The Wnt/β-catenin signaling pathway is frequently activated in hepatocellular carcinoma (HCC). Downstream signaling events involving the Wnt/β-catenin cascade occur through T-cell factor (TCF) proteins. The human TCF-4 gene is composed of 17 exons with multiple alternative splicing sites. However, the role of different TCF-4 isoforms in the pathogenesis of HCC is unknown. The purpose of this study was to identify and characterize TCF-4 isoforms in HCC. We identified 14 novel TCF-4 isoforms from four HCC cell lines. Functional analysis following transfection and expression in HCC cells revealed distinct effects on the phenotype. The TCF-4J isoform expression produced striking features of malignant transformation characterized by high cell proliferation rate, migration and colony formation even though its transcriptional activity was low. In contrast, the TCF-4K isoform displayed low TCF transcriptional activity; cell proliferation rate and colony formation were reduced as well. Interestingly, TCF-4J and TCF-4K differed by only five amino acids (the SxxSS motif). Thus, these studies suggest that conserved splicing motifs may have a major influence on the transcriptional activity and functional properties of TCF-4 isoforms and alter the characteristics of the malignant phenotype.

PMID:
21256126
PMCID:
PMC3066145
DOI:
10.1016/j.yexcr.2011.01.015
[Indexed for MEDLINE]
Free PMC Article

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