Down-regulation of monocyte chemotactic protein-3 by activated beta-catenin.
Accumulation of intracellular beta-catenin, as a result of inactivation of the adenomatous polyposis coli (APC) gene or by mutation of the beta-catenin gene (CTNNB1) itself, is involved in a wide range of human cancers. By means of fluorescent differential display using a murine fibroblast cell line (L-MT), which expresses an activated form of beta-catenin that accumulates in the cells, we found that expression of murine monocyte chemotactic protein-3 (mMCP-3) was suppressed by activated beta-catenin. Inversely, expression of MCP-3 in human colon cancer cells was induced by depletion of beta-catenin after adenovirus-mediated transfer of wild-type APC genes into the cells. A reporter-gene assay indicated that the accumulation of beta-catenin in the nucleus suppressed activity of the MCP-3 promoter through a putative T-cell factor/lymphocyte enhancer factor (Tcf/LEF)-binding site, ATCAAAG; but when the promoter sequence contained a two-base substitution in the binding site, it failed to suppress reporter-gene (luciferase) activity. An electrophoretic mobility-shift assay using the putative Tcf/LEF-binding sequence revealed interaction of the candidate sequence with the beta-catenin complex. Furthermore, induction of MCP-3 cDNA into HT-29 colon cancer cells increased expression of two markers of differentiation: alkaline phosphatase and carcinoembryonic antigen. Our results implied that activation of beta-catenin through the Tcf/LEF signaling pathway may participate in colonic carcinogenesis by inhibiting MCP-3-induced differentiation of colorectal epithelial cells.
Fujita
M
M
Laboratory of Molecular Medicine, Human Genome Center, Institute of Medical Science, The University of Tokyo, Japan.
Furukawa
Y
Y
Nagasawa
Y
Y
Ogawa
M
M
Nakamura
Y
Y
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D019556:COS Cells; D002454:Cell Differentiation / Q000235:genetics; D054410:Chemokine CCL7; D002522:Chlorocebus aethiops; D003106:Colon / Q000166:cytology; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D016207:Cytokines; D003598:Cytoskeletal Proteins / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation; D019073:HT29 Cells; D006801:Humans; D007739:L Cells; D051821:Lymphoid Enhancer-Binding Factor 1; D051379:Mice; D018945:Monocyte Chemoattractant Proteins / Q000096:biosynthesis / Q000235:genetics*; D011401:Promoter Regions, Genetic; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D051176:beta Catenin
C515450:CCL7 protein, human; C495270:CTNNB1 protein, human; C495267:CTNNB1 protein, mouse; C515451:Ccl7 protein, mouse; D054410:Chemokine CCL7; D016207:Cytokines; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D051821:Lymphoid Enhancer-Binding Factor 1; D018945:Monocyte Chemoattractant Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D051176:beta Catenin