The Wnt/β-Catenin Pathway is Activated as a Novel Nucleolar Stress Response
| Autor: | Astrid S. Pfister, Jasmin Tasic, David P. Dannheisig, Jana Bächle, Marina Keil |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Beta-catenin
Cell cycle checkpoint Genotype Ribosomopathy Nucleolus Ribosome biogenesis Cell Line Gene Knockout Techniques 03 medical and health sciences 0302 clinical medicine Genes Reporter Stress Physiological Structural Biology Humans Wnt Signaling Pathway Molecular Biology beta Catenin 030304 developmental biology 0303 health sciences biology Chemistry Wnt signaling pathway Nuclear Proteins RNA Cell biology Gene Expression Regulation Catenin Mutation biology.protein Tumor Suppressor Protein p53 Ribosomes Cell Nucleolus 030217 neurology & neurosurgery Protein Binding |
| Zdroj: | Journal of Molecular Biology. 433:166719 |
| ISSN: | 0022-2836 |
| DOI: | 10.1016/j.jmb.2020.11.018 |
| Popis: | Ribosomes are mandatory for growth and survival. The complex process of ribosome biogenesis is located in nucleoli and requires action of the RNA polymerases I–III, together with a multitude of processing factors involved in rRNA cleavage and maturation. Impaired ribosome biogenesis and loss of nucleolar integrity triggers nucleolar stress, which classically stabilizes the tumor suppressor p53 and induces cell cycle arrest and apoptosis. Nucleolar stress is implemented in modern anti-cancer therapies, however, also emerges as contributor to diverse pathological conditions. These include ribosomopathies, such as the Shwachman Bodian Diamond Syndrome (SBDS), which are not only characterized by nucleolar stress, but paradoxically also increased cancer incidence. Wnt signaling is tightly coupled to cell proliferation and is constitutively activated in various tumor types. In addition, the Wnt/β-Catenin pathway regulates ribosome formation. Here, we demonstrate that induction of nucleolar stress by different strategies stimulates the Wnt/β-Catenin pathway. We show that depletion of the key ribosomopathy factor SBDS, or the nucleolar factors Nucleophosmin (NPM), Pescadillo 1 (PES1) or Peter Pan (PPAN) by si RNA-mediated knockdown or CRISPR/Cas9 strategy activates Wnt/β-Catenin signaling in a β-Catenin-dependent manner and stabilizes β-Catenin in human cancer cells. Moreover, triggering nucleolar stress by the chemotherapeutic agents Actinomycin D or the RNA polymerase I inhibitor CX-5461 stimulates expression of Wnt/β-Catenin targets, which is followed by the p53 target CDKN1A (p21). As PPAN expression is induced by Wnt/β-Catenin signaling, our data establish a novel feedback mechanism and reveal that nucleolar stress over-activates the Wnt/β-Catenin pathway, which most likely serves as compensatory mechanism to sustain ribosome biogenesis. |
| Databáze: | OpenAIRE |
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