HIC1 Tumor Suppressor Loss Potentiates TLR2/NF-κB Signaling and Promotes Tissue Damage-Associated Tumorigenesis
Language English Country United States Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
25934696
DOI
10.1158/1541-7786.mcr-15-0033
PII: 1541-7786.MCR-15-0033
Knihovny.cz E-resources
- MeSH
- Azoxymethane MeSH
- Epithelial Cells MeSH
- Gene Knockdown Techniques MeSH
- Carcinogenesis metabolism MeSH
- Humans MeSH
- Disease Models, Animal MeSH
- Mice, Transgenic MeSH
- Mice MeSH
- Cell Line, Tumor MeSH
- Tumor Suppressor Proteins metabolism MeSH
- Colonic Neoplasms MeSH
- NF-kappa B metabolism MeSH
- Cell Proliferation MeSH
- Signal Transduction * MeSH
- Dextran Sulfate MeSH
- Intestines cytology MeSH
- Toll-Like Receptor 2 metabolism MeSH
- Kruppel-Like Transcription Factors genetics metabolism MeSH
- Up-Regulation MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Azoxymethane MeSH
- Hic1 protein, mouse MeSH Browser
- Tumor Suppressor Proteins MeSH
- NF-kappa B MeSH
- Dextran Sulfate MeSH
- Tlr2 protein, mouse MeSH Browser
- Toll-Like Receptor 2 MeSH
- Kruppel-Like Transcription Factors MeSH
UNLABELLED: Hypermethylated in cancer 1 (HIC1) represents a prototypic tumor suppressor gene frequently inactivated by DNA methylation in many types of solid tumors. The gene encodes a sequence-specific transcriptional repressor controlling expression of several genes involved in cell cycle or stress control. In this study, a Hic1 allele was conditionally deleted, using a Cre/loxP system, to identify genes influenced by the loss of Hic1. One of the transcripts upregulated upon Hic1 ablation is the toll-like receptor 2 (TLR2). Tlr2 expression levels increased in Hic1-deficient mouse embryonic fibroblasts (MEF) and cultured intestinal organoids or in human cells upon HIC1 knockdown. In addition, HIC1 associated with the TLR2 gene regulatory elements, as detected by chromatin immunoprecipitation, indicating that Tlr2 indeed represents a direct Hic1 target. The Tlr2 receptor senses "danger" signals of microbial or endogenous origin to trigger multiple signaling pathways, including NF-κB signaling. Interestingly, Hic1 deficiency promoted NF-κB pathway activity not only in cells stimulated with Tlr2 ligand, but also in cells treated with NF-κB activators that stimulate different surface receptors. In the intestine, Hic1 is mainly expressed in differentiated epithelial cells and its ablation leads to increased Tlr2 production. Finally, in a chemical-induced mouse model of carcinogenesis, Hic1 absence resulted in larger Tlr2-positive colonic tumors that showed increased proportion of proliferating cells. IMPLICATIONS: The tumor-suppressive function of Hic1 in colon is related to its inhibitory action on proproliferative signaling mediated by the Tlr2 receptor present on tumor cells.
References provided by Crossref.org
HIC1 Expression Distinguishes Intestinal Carcinomas Sensitive to Chemotherapy