5-ASA - colorectal cancer - cell death : an intriguing threesome

Colorectal cancer (CRC) is a complicated disease in which both genetic pre-desposition and environmental factors are important. Patients with inflammatory bowel disease (IBD) have an increased risk of developing CRC, and it is believed that treatment of IBD patients with 5-Aminosalicylic acid (5-ASA) reduces the CRC risk. The general purpose of the studies described in this thesis was to evaluate the effect of 5-ASA on the development of CRC, as well as determining the feasibility of introducing 5-ASA as an adjuvant therapy for CRC patients. Animal research showed that chronic 5-ASA medication has the ability to prevent colitis-associated CRC, confirming results from 5-ASA medication in IBD patients. Although 5-ASA was not able to prevent the development of sporadic CRC, 5-ASA treatment was found to hold a great promise for the treatment of CRC, by exerting CRC growth inhibiting, anti-progression and cell death inducing effects, and should be considered to be implemented in a future treatment strategy to CRC. Besides this, the determination of cell death products in the circulation of CRC patients and within the tumour, holds a great promise for selection of CRC patient treatment and patient folluw-up.UBL - phd migration 201

Зміст журналу за 2009 р.

Item does not contain fulltextT-helper 1 and 17 (Th1/Th17) responses are important in inflammatory bowel disease (IBD), and research indicates that Toll-like receptor 6 (TLR6) stimulation leads to Th17 cell development within the lung. The gastrointestinal tract, like the lung, is a mucosal surface that is exposed to bacterially derived TLR6 ligands. Thus, we looked at the effects of TLR6 stimulation on the expression of Th17-, Th1-, and regulatory T-cell-associated transcription factors; RORgammat, T-bet, and Foxp3, respectively; in CD4+ T cells within gut-associated lymphoid tissue (GALT) in vitro and in vivo. Cells from GALT and spleen were stimulated with anti-CD3 and TLR ligands for TLR1/2 and TLR2/6 (Pam3CSK4 and FSL-1, respectively). FSL-1 was more effective than Pam3CSK4 at inducing Th1 and Th17 responses in the GALT while Pam3CSK4 rivaled FSL-1 in the spleen. TLR6 was further explored in vivo using experimental colitis. Tlr6-/- mice were resistant to colitis, and oral FSL-1 led to more severe colitis in wild-type mice. Similar pro-inflammatory reactions were seen in human peripheral blood mononuclear cells, and TLR6 expression was directly correlated with RORC mRNA levels in inflamed intestines of IBD patients. These results demonstrate that TLR6 supports Th1- and Th17-skewed responses in the GALT and might be an important target for the development of new medical interventions in IBD

Loss of bone morphogenetic protein signaling in fibroblasts results in CXCL12-driven serrated polyp development

Mutations in Bone Morphogenetic Protein (BMP) Receptor (BMPR)1A and SMAD4 are detected in 50% of juvenile polyposis syndrome (JPS) patients, who develop stroma-rich hamartomatous polyps. The established role of stromal cells in regulating BMP activity in the intestine implies a role for stromal cells in polyp development. We used conditional Cre-LoxP mice to investigate how specific loss of BMPR1A in endothelial cells, fibroblasts, or myofibroblasts/smooth muscle cells affects intestinal homeostasis. Selective loss of BMPR1A in fibroblasts causes severe histological changes in the intestines with a significant increase in stromal cell content and epithelial cell hyperproliferation, leading to numerous serrated polyps. This phenotype suggests that crucial changes occur in the fibroblast secretome that influences polyp development. Analyses of publicly available RNA expression databases identified CXCL12 as a potential candidate. RNAscope in situ hybridization showed an evident increase of Cxcl12-expressing fibroblasts. In vitro, stimulation of fibroblasts with BMPs resulted in downregulation of CXCL12, while inhibition of the BMP pathway resulted in gradual upregulation of CXCL12 over time. Moreover, neutralization of CXCL12 in vivo in the fibroblast-specific BMPR1A KO mice resulted in a significant decrease in polyp formation. Finally, in CRC patient specimens, mRNA-expression data showed that patients with high GREMLIN1 and CXCL12 expression had a significantly poorer overall survival. Significantly higher GREMLIN1, NOGGIN, and CXCL12 expression were detected in the Consensus Molecular Subtype 4 (CMS4) colorectal cancers, which are thought to arise from serrated polyps. Taken together, these data imply that fibroblast-specific BMP signaling-CXCL12 interaction could have a role in the etiology of serrated polyp formation.Cellular mechanisms in basic and clinical gastroenterology and hepatolog

Collagen degradation and neutrophilic infiltration: a vicious circle in inflammatory bowel disease

Cellular mechanisms in basic and clinical gastroenterology and hepatolog

Epithelial argininosuccinate synthetase is dispensable for intestinal regeneration and tumorigenesis

The epithelial signaling pathways involved in damage and regeneration, and neoplastic transformation are known to be similar. We noted upregulation of argininosuccinate synthetase (ASS1) in hyperproliferative intestinal epithelium. Since ASS1 leads to de novo synthesis of arginine, an important amino acid for the growth of intestinal epithelial cells, its upregulation can contribute to epithelial proliferation necessary to be sustained during oncogenic transformation and regeneration. Here we investigated the function of ASS1 in the gut epithelium during tissue regeneration and tumorigenesis, using intestinal epithelial conditional Ass1 knockout mice and organoids, and tissue specimens from colorectal cancer patients. We demonstrate that ASS1 is strongly expressed in the regenerating and Apc-mutated intestinal epithelium. Furthermore, we observe an arrest in amino acid flux of the urea cycle, which leads to an accumulation of intracellular arginine. However, loss of epithelial Ass1 does not lead to a reduction in proliferation or increase in apoptosis in vivo, also in mice fed an arginine-free diet. Epithelial loss of Ass1 seems to be compensated by altered arginine metabolism in other cell types and the liver.Cellular mechanisms in basic and clinical gastroenterology and hepatolog

5-ASA - colorectal cancer - cell death : an intriguing threesome

Colorectal cancer (CRC) is a complicated disease in which both genetic pre-desposition and environmental factors are important. Patients with inflammatory bowel disease (IBD) have an increased risk of developing CRC, and it is believed that treatment of IBD patients with 5-Aminosalicylic acid (5-ASA) reduces the CRC risk. The general purpose of the studies described in this thesis was to evaluate the effect of 5-ASA on the development of CRC, as well as determining the feasibility of introducing 5-ASA as an adjuvant therapy for CRC patients. Animal research showed that chronic 5-ASA medication has the ability to prevent colitis-associated CRC, confirming results from 5-ASA medication in IBD patients. Although 5-ASA was not able to prevent the development of sporadic CRC, 5-ASA treatment was found to hold a great promise for the treatment of CRC, by exerting CRC growth inhibiting, anti-progression and cell death inducing effects, and should be considered to be implemented in a future treatment strategy to CRC. Besides this, the determination of cell death products in the circulation of CRC patients and within the tumour, holds a great promise for selection of CRC patient treatment and patient folluw-up

Targeting chemokine receptors in chronic inflammatory diseases: An extensive review

The traffic of the different types of immune cells is an important aspect in the immune response. Chemokines are soluble peptides that are able to attract cells by interaction with chemokine receptors on their target cells. Several different chemokines and receptors exist enabling the specific trafficking of different immune cells. In chronic inflammatory disorders there is abundance of immune cells present at the inflammatory site. This review focuses on the role of chemokine receptors in chronic inflammatory disorders of the lungs, intestine, joints, skin and nervous system and the potential of targeting these receptors as therapeutic intervention in these disorders. © 2011 Elsevier Inc. All rights reserved

5-Aminosalicylic Acid Interferes in the Cell Cycle of Colorectal Cancer Cells and Induces Cell Death Modes

Introduction: Epidemiological data suggests that 5-aminosalicyclic acid (5-ASA), a nonsteroidal antiinflammatory drug used in the treatment of inflammatory bowel diseases, prevents colorectal cancer development in these patients, although the mechanisms remain incompletely understood. Methods and Results: Here we report that 5-ASA prevents growth of several colorectal cancer cell lines by interfering in the cell cycle, i.e., an S-phase and G2/M phase arrest, dependent on 5-ASA dosage and concentration, together with an increased mitotic index. In addition, prolonged cell cycle arrest by repeated 5-ASA treatment induced apoptosis and caused abnormal spindle organization leading to mitotic catastrophe, another form of cell death. Conclusion: These observations illustrate that 5-ASA has chemopreventive and chemotherapeutic properties.Cellular mechanisms in basic and clinical gastroenterology and hepatolog

5-Aminosalicylic acid inhibits TGF-beta 1 signalling in colorectal cancer cells

The transforming growth factor-beta (TGF-beta) pathway is an important pathway in the initiation and progression of colorectal cancer. We aimed to determine the effects of 5-aminosalicylic acid (5-ASA) on TGF-beta signalling in colorectal cancer cells in vitro. 5-ASA inhibited TGF-beta 1 signalling in HCT1 16 cells and colonic fibroblasts, as judged by a TGF-beta-specific reporter gene assay, plasminogen activator inhibitor-1 mRNA and protein levels, fibroblast trans-differentiation, Smad3 phosphorylation and nuclear translocation. We conclude that 5-ASA inhibits TGF-beta 1 signalling in colorectal cancer cells, and might be a potent adjuvant therapeutic drug, interfering with aberrant TGF-beta signalling in colorectal cancer. (C) 2009 Elsevier Ireland Ltd. All rights reserved.Cellular mechanisms in basic and clinical gastroenterology and hepatolog

Toll-like receptor 6 stimulation promotes T-helper 1 and 17 responses in gastrointestinal-associated lymphoid tissue and modulates murine experimental colitis

Item does not contain fulltextT-helper 1 and 17 (Th1/Th17) responses are important in inflammatory bowel disease (IBD), and research indicates that Toll-like receptor 6 (TLR6) stimulation leads to Th17 cell development within the lung. The gastrointestinal tract, like the lung, is a mucosal surface that is exposed to bacterially derived TLR6 ligands. Thus, we looked at the effects of TLR6 stimulation on the expression of Th17-, Th1-, and regulatory T-cell-associated transcription factors; RORgammat, T-bet, and Foxp3, respectively; in CD4+ T cells within gut-associated lymphoid tissue (GALT) in vitro and in vivo. Cells from GALT and spleen were stimulated with anti-CD3 and TLR ligands for TLR1/2 and TLR2/6 (Pam3CSK4 and FSL-1, respectively). FSL-1 was more effective than Pam3CSK4 at inducing Th1 and Th17 responses in the GALT while Pam3CSK4 rivaled FSL-1 in the spleen. TLR6 was further explored in vivo using experimental colitis. Tlr6-/- mice were resistant to colitis, and oral FSL-1 led to more severe colitis in wild-type mice. Similar pro-inflammatory reactions were seen in human peripheral blood mononuclear cells, and TLR6 expression was directly correlated with RORC mRNA levels in inflamed intestines of IBD patients. These results demonstrate that TLR6 supports Th1- and Th17-skewed responses in the GALT and might be an important target for the development of new medical interventions in IBD