scholarly journals Inhibition of Wnt signaling by ICAT, a novel β-catenin-interacting protein

2000 ◽  
Vol 14 (14) ◽  
pp. 1741-1749 ◽  
Author(s):  
Ken-ichi Tago ◽  
Tsutomu Nakamura ◽  
Michiru Nishita ◽  
Junko Hyodo ◽  
Shin-ichi Nagai ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Transcription Factors ◽  
Embryonic Development ◽  
Wnt Signaling ◽  
Signaling Pathway ◽  
Target Genes ◽  
Wnt Signaling Pathway ◽  
Axis Formation ◽  
Interacting Protein

Wnt signaling has an important role in both embryonic development and tumorigenesis. β-Catenin, a key component of the Wnt signaling pathway, interacts with the TCF/LEF family of transcription factors and activates transcription of Wnt target genes. Here, we identify a novel β-catenin-interacting protein, ICAT, that was found to inhibit the interaction of β-catenin with TCF-4 and represses β-catenin–TCF-4-mediated transactivation. Furthermore, ICAT inhibited Xenopus axis formation by interfering with Wnt signaling. These results suggest that ICAT negatively regulates Wnt signaling via inhibition of the interaction between β-catenin and TCF and is integral in development and cell proliferation.

Evaluation of MACF1-regulatory non-coding RNA as a potential therapeutic target in Colorectal Cancer

QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Rowaida Mohammed Reda M. M Aboushahba ◽  
Fayda Ibrahim Abdel Motaleb ◽  
Ahmed Abdel Aziz Abou-Zeid ◽  
Enas Samir Nabil ◽  
Dalia Abdel-Wahab Mohamed ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Proliferation ◽  
Wnt Signaling ◽  
Cell Line ◽  
Signaling Pathway ◽  
Therapeutic Target ◽  
Molecular Mechanisms ◽  
Wnt Signaling Pathway ◽  
Control Group ◽  
Potential Therapeutic Target

ABSTRACT Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths world-wide. There is an increasing need for the identification of novel biomarkers/targets for early diagnosis and for the development of novel chemopreventive and therapeutic agents for CRC. Recently, MACF1 gene has emerged as a potential therapeutic target in cancer as it involved in processes critical for tumor cell proliferation, invasion and metastasis. It is suggested that MACF1 may function in cancers through Wnt signaling. MiR-34a is a well-known tumor suppressor miRNA.miR-34a targets MACF1 gene as a part of the wnt signaling pathway. In this study, 40 colonic tissues were collected from CRC patients (20) and control subjects (20). miR-34a-5p was assessed by real time PCR in all study groups. The results showed highly significant decrease (P < 0.01) in miR-34a relative expression in the CRC group (median RQ 0.13) when compared to the benign group (median RQ 5.3) and the healthy control group (median RQ 19.63). miR-34a mimic and inhibitor were transfected in CaCo-2 cell line and proliferation was assessed. The transfection of the cell line with miR-34a mimic decreased cell proliferation. Our study suggests that miR-34a-5p targets MACF1 gene as a part of the wnt signaling pathway leading to the involvement in the molecular mechanisms of CRC development and progression.

scholarly journals The microRNA miR-8 is a conserved negative regulator of Wnt signaling

2008 ◽  
Vol 105 (40) ◽  
pp. 15417-15422 ◽  
Author(s):  
Jennifer A. Kennell ◽  
Isabelle Gerin ◽  
Ormond A. MacDougald ◽  
Ken M. Cadigan
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathway ◽  
Target Genes ◽  
Wnt Signaling Pathway ◽  
Negative Regulator ◽  
Animal Development ◽  
Protein Levels ◽  
Evolutionarily Conserved ◽  
Multiple Levels

Wnt signaling plays many important roles in animal development. This evolutionarily conserved signaling pathway is highly regulated at all levels. To identify regulators of the Wnt/Wingless (Wg) pathway, we performed a genetic screen in Drosophila. We identified the microRNA miR-8 as an inhibitor of Wg signaling. Expression of miR-8 potently antagonizes Wg signaling in vivo, in part by directly targeting wntless, a gene required for Wg secretion. In addition, miR-8 inhibits the pathway downstream of the Wg signal by repressing TCF protein levels. Another positive regulator of the pathway, CG32767, is also targeted by miR-8. Our data suggest that miR-8 potently antagonizes the Wg pathway at multiple levels, from secretion of the ligand to transcription of target genes. In addition, mammalian homologues of miR-8 promote adipogenesis of marrow stromal cells by inhibiting Wnt signaling. These findings indicate that miR-8 family members play an evolutionarily conserved role in regulating the Wnt signaling pathway.

scholarly journals Maternal Wnt11 Activates the Canonical Wnt Signaling Pathway Required for Axis Formation in Xenopus Embryos

Cell ◽  
2005 ◽  
Vol 120 (6) ◽  
pp. 857-871 ◽  
Author(s):  
Qinghua Tao ◽  
Chika Yokota ◽  
Helbert Puck ◽  
Matt Kofron ◽  
Bilge Birsoy ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Axis Formation ◽  
Canonical Wnt Signaling ◽  
Xenopus Embryos ◽  
Canonical Wnt

scholarly journals Desumoylation Activity of Axam, a Novel Axin-Binding Protein, Is Involved in Downregulation of β-Catenin

2002 ◽  
Vol 22 (11) ◽  
pp. 3803-3819 ◽  
Author(s):  
Takayuki Kadoya ◽  
Hideki Yamamoto ◽  
Toshiaki Suzuki ◽  
Akira Yukita ◽  
Akimasa Fukui ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathway ◽  
Catalytic Domain ◽  
Binding Protein ◽  
Wnt Signaling Pathway ◽  
Binding Domain ◽  
Axis Formation ◽  
Intact Cells ◽  
Specific Protease

ABSTRACT Axam has been identified as a novel Axin-binding protein that inhibits the Wnt signaling pathway. We studied the molecular mechanism by which Axam stimulates the downregulation of β-catenin. The C-terminal region of Axam has an amino acid sequence similar to that of the catalytic region of SENP1, a SUMO-specific protease (desumoylation enzyme). Indeed, Axam exhibited activity to remove SUMO from sumoylated proteins in vitro and in intact cells. The Axin-binding domain is located in the central region of Axam, which is different from the catalytic domain. Neither the Axin-binding domain nor the catalytic domain alone was sufficient for the downregulation of β-catenin. An Axam fragment which contains both domains was able to decrease the level of β-catenin. On substitution of Ser for Cys547 in the catalytic domain, Axam lost its desumoylation activity. Further, this Axam mutant decreased the activity to downregulate β-catenin. Although Axam strongly inhibited axis formation and expression of siamois, a Wnt-response gene, in Xenopus embryos, AxamC547S showed weak activities. These results demonstrate that Axam functions as a desumoylation enzyme to downregulate β-catenin and suggest that sumoylation is involved in the regulation of the Wnt signaling pathway.

scholarly journals The endocannabinoid anandamide inhibits cholangiocarcinoma growth via activation of the noncanonical Wnt signaling pathway

2008 ◽  
Vol 295 (6) ◽  
pp. G1150-G1158 ◽  
Author(s):  
Sharon DeMorrow ◽  
Heather Francis ◽  
Eugenio Gaudio ◽  
Julie Venter ◽  
Antonio Franchitto ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Tumor Growth ◽  
Wnt Signaling ◽  
Signaling Pathway ◽  
Calcium Release ◽  
Wnt Signaling Pathway ◽  
Xenograft Model ◽  
Orphan Receptor

Cholangiocarcinomas are cancers that have poor prognosis and limited treatment options. The noncanonical Wnt pathway is mediated predominantly by Wnt 5a, which activates a Ca2+-dependent pathway involving protein kinase C, or a Ca2+-independent pathway involving the orphan receptor Ror2 and subsequent activation of Jun NH2-terminal kinase (JNK). This pathway is associated with growth-suppressing effects in numerous cell types. We have shown that anandamide decreases cholangiocarcinoma growth in vitro. Therefore, we determined the effects of anandamide on cholangiocarcinoma tumor growth in vivo using a xenograft model and evaluated the effects of anandamide on the noncanonical Wnt signaling pathways. Chronic administration of anandamide decreased tumor growth and was associated with increased Wnt 5a expression in vitro and in vivo. Treatment of cholangiocarcinoma cells with recombinant Wnt 5a decreased cell proliferation in vitro. Neither anandamide nor Wnt 5a affected intracellular calcium release, but both increased the JNK phosphorylation. Stable knockdown of Wnt 5a or Ror2 expression in cholangiocarcinoma cells abolished the effects of anandamide on cell proliferation and JNK activation. Modulation of the endocannabinoid system may be important in cholangiocarcinoma treatment. The antiproliferative actions of the noncanonical Wnt signaling pathway warrants further investigation to dissect the mechanism by which this may occur.

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