Intestinal stem cell overproliferation resulting from inactivation of the APC tumor suppressor requires the transcription cofactors Earthbound and Erect wing.

Wnt/β-catenin signal transduction directs intestinal stem cell (ISC) proliferation during homeostasis. Hyperactivation of Wnt signaling initiates colorectal cancer, which most frequently results from truncation of the tumor suppressor Adenomatous polyposis coli (APC). The β-catenin-TCF transcription...

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Main Authors: Ai Tian, Hassina Benchabane, Zhenghan Wang, Chloe Zimmerman, Nan Xin, Jessica Perochon, Gabriela Kalna, Owen J Sansom, Chao Cheng, Julia B Cordero, Yashi Ahmed
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2017-07-01
Series:PLoS Genetics
Online Access:https://journals.plos.org/plosgenetics/article/file?id=10.1371/journal.pgen.1006870&type=printable
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author Ai Tian
Hassina Benchabane
Zhenghan Wang
Chloe Zimmerman
Nan Xin
Jessica Perochon
Gabriela Kalna
Owen J Sansom
Chao Cheng
Julia B Cordero
Yashi Ahmed
author_facet Ai Tian
Hassina Benchabane
Zhenghan Wang
Chloe Zimmerman
Nan Xin
Jessica Perochon
Gabriela Kalna
Owen J Sansom
Chao Cheng
Julia B Cordero
Yashi Ahmed
author_sort Ai Tian
collection DOAJ
description Wnt/β-catenin signal transduction directs intestinal stem cell (ISC) proliferation during homeostasis. Hyperactivation of Wnt signaling initiates colorectal cancer, which most frequently results from truncation of the tumor suppressor Adenomatous polyposis coli (APC). The β-catenin-TCF transcription complex activates both the physiological expression of Wnt target genes in the normal intestinal epithelium and their aberrantly increased expression in colorectal tumors. Whether mechanistic differences in the Wnt transcription machinery drive these distinct levels of target gene activation in physiological versus pathological states remains uncertain, but is relevant for the design of new therapeutic strategies. Here, using a Drosophila model, we demonstrate that two evolutionarily conserved transcription cofactors, Earthbound (Ebd) and Erect wing (Ewg), are essential for all major consequences of Apc1 inactivation in the intestine: the hyperactivation of Wnt target gene expression, excess number of ISCs, and hyperplasia of the epithelium. In contrast, only Ebd, but not Ewg, mediates the Wnt-dependent regulation of ISC proliferation during homeostasis. Therefore, in the adult intestine, Ebd acts independently of Ewg in physiological Wnt signaling, but cooperates with Ewg to induce the hyperactivation of Wnt target gene expression following Apc1 loss. These findings have relevance for human tumorigenesis, as Jerky (JRK/JH8), the human Ebd homolog, promotes Wnt pathway hyperactivation and is overexpressed in colorectal, breast, and ovarian cancers. Together, our findings reveal distinct requirements for Ebd and Ewg in physiological Wnt pathway activation versus oncogenic Wnt pathway hyperactivation following Apc1 loss. Such differentially utilized transcription cofactors may offer new opportunities for the selective targeting of Wnt-driven cancers.
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spelling doaj-art-6d876a7a5a984076a577cd01fdc0c85d2025-08-20T02:01:57ZengPublic Library of Science (PLoS)PLoS Genetics1553-73901553-74042017-07-01137e100687010.1371/journal.pgen.1006870Intestinal stem cell overproliferation resulting from inactivation of the APC tumor suppressor requires the transcription cofactors Earthbound and Erect wing.Ai TianHassina BenchabaneZhenghan WangChloe ZimmermanNan XinJessica PerochonGabriela KalnaOwen J SansomChao ChengJulia B CorderoYashi AhmedWnt/β-catenin signal transduction directs intestinal stem cell (ISC) proliferation during homeostasis. Hyperactivation of Wnt signaling initiates colorectal cancer, which most frequently results from truncation of the tumor suppressor Adenomatous polyposis coli (APC). The β-catenin-TCF transcription complex activates both the physiological expression of Wnt target genes in the normal intestinal epithelium and their aberrantly increased expression in colorectal tumors. Whether mechanistic differences in the Wnt transcription machinery drive these distinct levels of target gene activation in physiological versus pathological states remains uncertain, but is relevant for the design of new therapeutic strategies. Here, using a Drosophila model, we demonstrate that two evolutionarily conserved transcription cofactors, Earthbound (Ebd) and Erect wing (Ewg), are essential for all major consequences of Apc1 inactivation in the intestine: the hyperactivation of Wnt target gene expression, excess number of ISCs, and hyperplasia of the epithelium. In contrast, only Ebd, but not Ewg, mediates the Wnt-dependent regulation of ISC proliferation during homeostasis. Therefore, in the adult intestine, Ebd acts independently of Ewg in physiological Wnt signaling, but cooperates with Ewg to induce the hyperactivation of Wnt target gene expression following Apc1 loss. These findings have relevance for human tumorigenesis, as Jerky (JRK/JH8), the human Ebd homolog, promotes Wnt pathway hyperactivation and is overexpressed in colorectal, breast, and ovarian cancers. Together, our findings reveal distinct requirements for Ebd and Ewg in physiological Wnt pathway activation versus oncogenic Wnt pathway hyperactivation following Apc1 loss. Such differentially utilized transcription cofactors may offer new opportunities for the selective targeting of Wnt-driven cancers.https://journals.plos.org/plosgenetics/article/file?id=10.1371/journal.pgen.1006870&type=printable
spellingShingle Ai Tian
Hassina Benchabane
Zhenghan Wang
Chloe Zimmerman
Nan Xin
Jessica Perochon
Gabriela Kalna
Owen J Sansom
Chao Cheng
Julia B Cordero
Yashi Ahmed
Intestinal stem cell overproliferation resulting from inactivation of the APC tumor suppressor requires the transcription cofactors Earthbound and Erect wing.
PLoS Genetics
title Intestinal stem cell overproliferation resulting from inactivation of the APC tumor suppressor requires the transcription cofactors Earthbound and Erect wing.
title_full Intestinal stem cell overproliferation resulting from inactivation of the APC tumor suppressor requires the transcription cofactors Earthbound and Erect wing.
title_fullStr Intestinal stem cell overproliferation resulting from inactivation of the APC tumor suppressor requires the transcription cofactors Earthbound and Erect wing.
title_full_unstemmed Intestinal stem cell overproliferation resulting from inactivation of the APC tumor suppressor requires the transcription cofactors Earthbound and Erect wing.
title_short Intestinal stem cell overproliferation resulting from inactivation of the APC tumor suppressor requires the transcription cofactors Earthbound and Erect wing.
title_sort intestinal stem cell overproliferation resulting from inactivation of the apc tumor suppressor requires the transcription cofactors earthbound and erect wing
url https://journals.plos.org/plosgenetics/article/file?id=10.1371/journal.pgen.1006870&type=printable
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