1. MAD1 upregulation sensitizes to inflammation-mediated tumor formation.
- Author
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Copeland SE, Snow SM, Wan J, Matkowskyj KA, Halberg RB, and Weaver BA
- Subjects
- Animals, Female, Humans, Male, Mice, Carcinogenesis, Chromosomal Instability, CRISPR-Cas Systems, Dextran Sulfate, Gene Expression Regulation, Neoplastic, Nuclear Proteins genetics, Nuclear Proteins metabolism, Tumor Suppressor Protein p53 genetics, Tumor Suppressor Protein p53 metabolism, Up-Regulation, Cell Cycle Proteins metabolism, Colonic Neoplasms genetics, Colonic Neoplasms pathology, Inflammation metabolism
- Abstract
Mitotic Arrest Deficient 1 (gene name MAD1L1), an essential component of the mitotic spindle assembly checkpoint, is frequently overexpressed in colon cancer, which correlates with poor disease-free survival. MAD1 upregulation induces two phenotypes associated with tumor promotion in tissue culture cells-low rates of chromosomal instability (CIN) and destabilization of the tumor suppressor p53. Using CRISPR/Cas9 gene editing, we generated a novel mouse model by inserting a doxycycline (dox)-inducible promoter and HA tag into the endogenous mouse Mad1l1 gene, enabling inducible expression of HA-MAD1 following exposure to dox in the presence of the reverse tet transactivator (rtTA). A modest 2-fold overexpression of MAD1 in murine colon resulted in decreased p53 expression and increased mitotic defects consistent with CIN. After exposure to the colon-specific inflammatory agent dextran sulfate sodium (DSS), 31% of mice developed colon lesions, including a mucinous adenocarcinoma, while none formed in control animals. Lesion incidence was particularly high in male mice, 57% of which developed at least one hyperplastic polyp, adenoma or adenocarcinoma in the colon. Notably, mice expressing HA-MAD1 also developed lesions in tissues in which DSS is not expected to induce inflammation. These findings demonstrate that MAD1 upregulation is sufficient to promote colon tumorigenesis in the context of inflammation in immune-competent mice., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Copeland et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
- Published
- 2024
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