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ABSTRACT The methyltransferase enhancer of zeste homolog 2 (EZH2) regulates gene expression, and aberrant EZH2 expression and signaling can drive fibrosis and cancer. However, it is not clear how chemical and mechanical signals are integrated to regulate EZH2 and gene expression. We show that culture of cells on stiff matrices in concert with transforming growth factor (TGF)-β1 promotes nuclear localization of EZH2 and an increase in the levels of the corresponding histone modification, H3K27me3, thereby regulating gene expression. EZH2 activity and expression are required for TGFβ1- and stiffness-induced increases in H3K27me3 levels as well as for morphological and gene expression changes associated with epithelial–mesenchymal transition (EMT). Inhibition of Rho associated kinase (ROCK) proteins or myosin II signaling attenuates TGFβ1-induced nuclear localization of EZH2 and decreases H3K27me3 levels in cells cultured on stiff substrata, suggesting that cellular contractility, in concert with a major cancer signaling regulator TGFβ1, modulates EZH2 subcellular localization. These findings provide a contractility-dependent mechanism by which matrix stiffness and TGFβ1 together mediate EZH2 signaling to promote EMT.
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This content will become publicly available on March 1, 2026
Interplay Between TGFβ1 Signaling and Cancer-Testis Antigen MAGEB2: A New Thorn in Cancer’s Side?
The Melanoma Antigen Gene (MAGE) family of proteins is the largest family of cancer-testis antigens (CTAs) and shares a MAGE homology domain (MHD). MAGE proteins are divided into Type I and Type II MAGEs depending on their chromosomal location and expression patterns. Type I MAGEs are true CTAs. MAGEB2 is a Type I MAGE, belonging to the MAGEB subfamily, and unlike some MAGE proteins, has not been found to bind to and enhance E3 ligase activity. MAGEB2 has been discovered to be an RNA-binding protein that serves to protect spermatogonial cells in the testis from extraneous stressors. We have discovered that MAGEB2 is necessary and sufficient for the proliferation of cells and is expressed by the differential DNA methylation of its gene promoter. Furthermore, we identified JunD as the transcription factor that regulates MAGEB2 expression. When expressed, MAGEB2 suppresses transforming grown factor-β1 (TGFβ1) signaling by decreasing mRNA levels of Thrombospondin-1 (TSP-1). TSP-1 is an anti-angiogenic protein that activates TGFβ1. Restoring levels of TSP-1 or TGFβ1 results in the inability of MAGEB2 to drive proliferation, suggesting that MAGEB2-expressing tumors might be more susceptible to therapies that induce or activate TSP-1 or TGFβ1 signaling.
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- Award ID(s):
- 1955975
- PAR ID:
- 10637304
- Publisher / Repository:
- Pubmed
- Date Published:
- Journal Name:
- International Journal of Molecular Sciences
- Volume:
- 26
- Issue:
- 6
- ISSN:
- 1422-0067
- Page Range / eLocation ID:
- 2448
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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