| β-catenin/T cell factor (TCF) signaling pathway plays a key role in the development and growth of the cell, mainly in the endodermally derived organs. The important roles of the p-catenin/TCF signaling pathway were also reported in colorectal, gastrointestinal and liver cancer cell. p-catenin and TCF-4 are the important signaling molecules. As a multifunctional protein, p-catenin constructs the cell membrane with E-cadherin on one hand, translocates into the nuclei where its association with TCF-4 causes transcriptional activation of target genes on the other hand. Although there are many reports about β-catenin in NSCLC, the relationships between β-catenin and NSCLC are not clear completely. TCF-4 is the main member of TCF family, which have the conservative High Mobility Group (HMG)-box. Little is known about the change of human TCF-4 in the lung cancer expected for some reports in lung cell lines. To further understanding the role of the p-catenin/TCF-4 signaling pathway on the onset or progression of lung cancer, the present study examined the distribution and expression of β-catenin/TCF-4 and their complex in non-small-cell lung cancer (NSCLC) by immunofluorescence , immiinohistochemistry , reverse transcription polymerase chain reaction (RT-PCR) and Western blotting, respectively.Methods1 Sixty cases with non-small-cell lung cancer and eight adjacent para-cancerous tissues were obtained from September 2001 to March 2003, diagnosed pathologically.2 Thirty-five of these cases were used to investigate the distribution of p-catenin by immunofluorescence and laser confocal scanning microscope. By the staining of normal cell membrane as a positive control, the staining of tumor cell membrane was divided into 2 categories: fifty percent or more of tumor cell membranes stained positive and less than fifty percent of tumor cell membranes stained positive. Nuclear expression was scored positive if the general shape or location of the nucleus could be determined from the protein expression.3 The mRNA expression of β-catenin was detected by one-step RT-PCR. The integrated density values of PCR productions were analyzed semiquantita-tively.4 Immunohistochemistry was used to investigate the distribution of TCF-4. The staining patterns of tumors were divided into 4 categories: only nuclear staining or nuclear staining being more than cytoplasmic staining, only cytoplasmic staining or cytoplasmic staining being more than nuclear staining, nuclear staining and cytoplasmic staining equally, no nuclear staining and cytoplasmic staining. The integrated OD values of all sections were analyzed by MetaMorph image analysis software.5 The mRNA expression of TCF-4 was detected by one-step RT-PCR. The integrated density values of PCR productions were analyzed semiquantitatively.6 The protein of nuclear extracts was prepared by super-speed centrifuge.7 For immunoprecipitation of β-catenin/TCF-4 complex, the proteinA and polyclonal antibody against TCF-4 were added to the lysates. Then Western blotting was performed with monoclonal antibody against β-catenin.Results1 Immunofluorescence showed that the membranous expression of β -catenin reduced severely in the thirty-seven percent of NSCLC. Furthermore, the membranous expression was significantly more heterogeneous in tumors than in normal tissues. There was no difference of β-catenin expression investigated in his-tological classification and cell differentiation. β-catenin accumulated in the one hundred percent of the cytoplasm and the fifty-one percent of the nuclei.2 The mRNA expression of β-catenin in the carcinoma was higher than thatin the para-cancerous tissues (0. 28 + 0. 20, 0. 11 + 0. 08, P < 0. 01). There was no difference in histological classification and cell differentiation. The mR-NA expression in the group of lower membranous expression of p-catenin was significantly higher than that in the group of membranous expression of p-catenin (0.43 + 0. 18,0. 21 + 0. 08,P <0. 01). However, there was no dif...
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