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Context-dependent activation of Wnt signaling by tumor suppressor RUNX3 in gastric cancer cells.

Ju X, Ishikawa TO, Naka K, Ito K, Ito Y, Oshima M - Cancer Sci. (2014)

Bottom Line: Here, we confirmed that RUNX3 suppressed Wnt signaling activity in several gastric cancer cell lines; however, we found that RUNX3 increased the Wnt signaling activity in KatoIII and SNU668 gastric cancer cells.As found previously, RUNX3 also binds to TCF4 and β-catenin in KatoIII cells, suggesting that these molecules form a ternary complex.These results indicate that RUNX3 can either suppress or activate the Wnt signaling pathway through its binding to the TCF4/β-catenin complex by cell context-dependent mechanisms.

View Article: PubMed Central - PubMed

Affiliation: Division of Genetics, Cancer Research Institute, Kanazawa University, Kanazawa, Japan.

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Related in: MedlinePlus

Binding of the RUNX3, TCF4 and β-catenin complex to Wnt target gene promoters. (a) Immunoprecipitation for β-catenin and TCF4 with an anti-Flag (RUNX3) antibody. (b) ChIP analyses of the Axin2 (left) and c-Myc (right) promoter regions using lysates precipitated (IP) with anti-TCF4, anti-β-catenin and anti-RUNX3 antibodies. Lanes 1 and 4, control KatoIII cells; Lanes 2 and 5, RUNX3-expressing KatoIII cells; and Lanes 3 and 6, R122C mutant RUNX3-expressing KatoIII cells. (c,d) ChIP-based real-time PCR for the Axin2 (c) and c-Myc (d) promoters (mean ± SD). ChIP samples were precipitated (IP) with anti-TCF4, anti-unphosphorylated β-catenin or anti-RUNX3 antibodies from control cells (blue), RUNX3-expressing KatoIII cells (orange) or R122C mutant RUNX3-expressing KatoIII cells (green), and examined by real-time PCR. *P < 0.05 versus control.
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fig05: Binding of the RUNX3, TCF4 and β-catenin complex to Wnt target gene promoters. (a) Immunoprecipitation for β-catenin and TCF4 with an anti-Flag (RUNX3) antibody. (b) ChIP analyses of the Axin2 (left) and c-Myc (right) promoter regions using lysates precipitated (IP) with anti-TCF4, anti-β-catenin and anti-RUNX3 antibodies. Lanes 1 and 4, control KatoIII cells; Lanes 2 and 5, RUNX3-expressing KatoIII cells; and Lanes 3 and 6, R122C mutant RUNX3-expressing KatoIII cells. (c,d) ChIP-based real-time PCR for the Axin2 (c) and c-Myc (d) promoters (mean ± SD). ChIP samples were precipitated (IP) with anti-TCF4, anti-unphosphorylated β-catenin or anti-RUNX3 antibodies from control cells (blue), RUNX3-expressing KatoIII cells (orange) or R122C mutant RUNX3-expressing KatoIII cells (green), and examined by real-time PCR. *P < 0.05 versus control.

Mentions: It has previously been shown that RUNX3 binds to TCF4/β-catenin complex, which suppresses the binding of the complex to the Wnt target gene promoters.(12,13) Notably, immunoprecipitation experiments revealed that RUNX3 bound β-catenin and TCF4 also in the RUNX3-transfected KatoIII cells (Fig. 5a), suggesting that RUNX3, TCF4 and β-catenin form a ternary complex also in KatoIII cells.


Context-dependent activation of Wnt signaling by tumor suppressor RUNX3 in gastric cancer cells.

Ju X, Ishikawa TO, Naka K, Ito K, Ito Y, Oshima M - Cancer Sci. (2014)

Binding of the RUNX3, TCF4 and β-catenin complex to Wnt target gene promoters. (a) Immunoprecipitation for β-catenin and TCF4 with an anti-Flag (RUNX3) antibody. (b) ChIP analyses of the Axin2 (left) and c-Myc (right) promoter regions using lysates precipitated (IP) with anti-TCF4, anti-β-catenin and anti-RUNX3 antibodies. Lanes 1 and 4, control KatoIII cells; Lanes 2 and 5, RUNX3-expressing KatoIII cells; and Lanes 3 and 6, R122C mutant RUNX3-expressing KatoIII cells. (c,d) ChIP-based real-time PCR for the Axin2 (c) and c-Myc (d) promoters (mean ± SD). ChIP samples were precipitated (IP) with anti-TCF4, anti-unphosphorylated β-catenin or anti-RUNX3 antibodies from control cells (blue), RUNX3-expressing KatoIII cells (orange) or R122C mutant RUNX3-expressing KatoIII cells (green), and examined by real-time PCR. *P < 0.05 versus control.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4317806&req=5

fig05: Binding of the RUNX3, TCF4 and β-catenin complex to Wnt target gene promoters. (a) Immunoprecipitation for β-catenin and TCF4 with an anti-Flag (RUNX3) antibody. (b) ChIP analyses of the Axin2 (left) and c-Myc (right) promoter regions using lysates precipitated (IP) with anti-TCF4, anti-β-catenin and anti-RUNX3 antibodies. Lanes 1 and 4, control KatoIII cells; Lanes 2 and 5, RUNX3-expressing KatoIII cells; and Lanes 3 and 6, R122C mutant RUNX3-expressing KatoIII cells. (c,d) ChIP-based real-time PCR for the Axin2 (c) and c-Myc (d) promoters (mean ± SD). ChIP samples were precipitated (IP) with anti-TCF4, anti-unphosphorylated β-catenin or anti-RUNX3 antibodies from control cells (blue), RUNX3-expressing KatoIII cells (orange) or R122C mutant RUNX3-expressing KatoIII cells (green), and examined by real-time PCR. *P < 0.05 versus control.
Mentions: It has previously been shown that RUNX3 binds to TCF4/β-catenin complex, which suppresses the binding of the complex to the Wnt target gene promoters.(12,13) Notably, immunoprecipitation experiments revealed that RUNX3 bound β-catenin and TCF4 also in the RUNX3-transfected KatoIII cells (Fig. 5a), suggesting that RUNX3, TCF4 and β-catenin form a ternary complex also in KatoIII cells.

Bottom Line: Here, we confirmed that RUNX3 suppressed Wnt signaling activity in several gastric cancer cell lines; however, we found that RUNX3 increased the Wnt signaling activity in KatoIII and SNU668 gastric cancer cells.As found previously, RUNX3 also binds to TCF4 and β-catenin in KatoIII cells, suggesting that these molecules form a ternary complex.These results indicate that RUNX3 can either suppress or activate the Wnt signaling pathway through its binding to the TCF4/β-catenin complex by cell context-dependent mechanisms.

View Article: PubMed Central - PubMed

Affiliation: Division of Genetics, Cancer Research Institute, Kanazawa University, Kanazawa, Japan.

Show MeSH
Related in: MedlinePlus