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Objective To investigate the role of T cell factor-4 (TCF-4) in the carcinogenesis of colorectal cancer. Methods Relevant references about TCF-4 and the carcinogenesis of colorectal cancer, which were published recently domestic and abroad, were collected and reviewed. Results For TCF-4 gene, multiple isoforms are generated by way of alternative splicing, which encode different proteins. TCF-4 protein is sequence-specific DNA binding protein and is incapable of activating or repressing transcription independently, but it can interact with distinct partners to lead to different effects through multiple domains. Conclusion TCF-4 might be viewed as nuclear vehicles targeting other auxiliary proteins to a specific set of promoters and functions as molecular switch during the carcinogenesis of colorectal cancer.
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Objective To investigate the effects of dominant-negative truncation mutant?NTCF4, lacking the N-terminal form of TCF4 gene,on biological characteristics of renal cancer cell line GRC-I and explore the molecular mechanisms.Methods GRC-I cell was transfected with pCDNA3-?NTCF4 eukary- otie expression plasmid,pCDNA3 empty vector to construct the stable cell line GRC-I/?NTCF4 and GRC-I/ Mock respectively.The morphological changes of stable cells were observed and the cells growth curve was detected through light microscope.The cellular proliferation activities were determined using the MTT assay. The protein expression of Wnt pathway downstream target gene C-Myc and Cox-2 was evaluated by immuno- cytoehemieal method and Western Blot analysis.Results After the dominant-negative?NTCF4 gene was permanently expressed,the GRC-I/?NTCF4 stable cells morphologically showed that appearance changed from circular to long-spindle shape,growth rate decreased with less karyosehisis found,malignant pheno- types reversed to normal renal tubular cells.MTT assay revealed that the proliferation activities of GRC-1/?NTCF4 cells were inhibited by 11.2%-35.5% compared with GRC-I cells (P＜0.05),while the GRC- I/Mock cells have no difference with the control cells.Immunocytochemical analysis and Western Blot showed that the C-Myc and Cox-2 protein expression level of GRC-I/?ANTCF4 cells were significantly sup- pressed in comparison with that of GRC-I/Mock and GRC-I cells.Conclusions The dominant-negative truncation mutant?NTCF4 could partially inhibit the growth of renal cancer cells and down-regulate the pro- tein expression of Wnt pathway target gene C-Myc and Cox-2.These findings provide a experimental founda- tion for applying cell signal therapy to renal cell cancer by blocking the Wnt signaling pathway.