liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Inflammation and Intestinal Homeostasis-Associated Genes in Colorectal Cancer
Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Colorectal cancer (CRC) is a global ‘killer’ and every year more than 1.2 million new individuals are affected and approximately 600 000 succumb to the disorder. Several mechanisms such as inactivation of tumor suppressor genes, activation of oncogenes and dysregulation of cell fate determinating pathways e.g. Wnt and Notch can initiate a cancerous cell growth and promote colorectal tumorigenesis. In addition, most tumors are exposed to an inflammatory environment, which together with the presence of mitogenic and angiogenic signals may sustain several hallmarks of cancer. Genetic alterations in inflammatory genes are associated with chronic inflammatory bowel disease, which is a strong risk factor of developing CRC. Scientists have for a long time looked for ‘the Key’ that would unlock the ‘cancer door’ but more likely cancer should be considered as not one but many diseases where almost every single patient is genetically and clinically unique. Hence recent research has turned to identify such inter-individual discrepancies and to find disease markers and strategies for guiding clinicians when tailoring individual management and optimized therapy. A deeper understanding of the regulation and genetic variation of inflammation and intestinal-homeostasis associated genes is pivotal to find potential targets for future therapies.

The present thesis focuses on genetic variation and alterations in inflammatory genes as well as genes specifically involved in maintaining intestinal homeostasis. The most common anti-inflammatory drugs, NSAIDs, inhibit the prostanoid-generating COX-enzymes and are associated with decreased CRC risk when administered for a long time. Unfortunately, continuous NSAID treatment may lead to severe side-effects such as gastrointestinal bleeding, possibly through the ablation of non-PGE2 prostanoids. Therefore, a more specific inhibition of PGE2 has been suggested to be superior to classical NSAIDs. In papers I and II, the terminal PGE2 generating enzyme mPGES1 was studied in the context of intestinal cancer. Unexpectedly, ApcMin/+ mice with a targeted deletion of the mPGES1 encoding gene displayed significantly more and larger intestinal adenomas as compared to their wilde-type (wt) littermates. Probably this was due to the redirected generation of PGE2 towards non-PGE2 prostanoids seen in the murine tumors, resulting in enhanced pro-tumorigenic activity of these transmitter substances. Next, with a battery of functional and descriptive assays we investigated whether the outcome of mPGES1 expression and activity could depend on the genetic profile of the tumor e.g. the Apc mutational status. Indeed, high expression of mPGES1 was associated with the presence of wt-Apc, both in vitro and in vivo, most likely depending on mPGES1 mRNA stabilization rather than upregulation through β–catenin/Lef/Tcf4 signaling.

NFκB is a major regulator of inflammation e.g. through the production of inflammatory cytokines. Variations in genes controlling inflammation and angiogenesis could potentially be used as biomarkers to identify patients with increased risk of CRC development, and/or to identify those with high risk of a rapidly progressing disease. Further, such analyzes have been suggested to select patients, which may benefit from specific anti-inflammatory or anti-angiogenic therapies. In paper III, genetic alterations in NFκB associated genes were studied among CRC patients and healthy controls. The NFκB negative regulator TNFAIP3 was found to exert tumor suppressive functions in CRC and moreover, homozygous mutant TNFAIP3 (rs6920220), homozygous mutant NFκB -94 ATTG ins/del and heterozygous NLRP3 (Q705K) were identified as prognostic markers for identifying CRC patients with a high risk of rapid progression. Further studies, which focus on the potential to treat such patients with anti-inflammatory IL-1β targeting therapies, are warranted.

In the intestinal epithelium, Notch and Wnt signaling function in synergy to maintain homeostasis and together these pathways promote stem cell renewal and drive proliferation. Thus, dysregulation and/or overactivation of one of the two pathways could potentially lead to simultaneous activation of the other. While the genetic mechanisms explaining aberrant Wnt signaling in CRC are well-known, the reasons for the Notch pathway activation are less so. Further, relatively little is known about the mechanisms linking the two pathways in CRC. In paper IV, we addressed this question with a set of experimental in vitro assays, hereby identifying Notch2 together with several additional genes classically belonging to the Notch pathway, as putative targets for canonical and non-canonical Wnt signaling. We therefore suggest that aberrant Notch signaling in colon cancer cells may be the result of dysregulated Wnt signaling.

In summary, the results here presented add a couple of pieces to the immensely complex jigsaw puzzle connecting intestinal homeostasis, inflammation and CRC. These results may aid in identifying future biomarkers or potential drug targets that could take us to the next level in the war against cancer.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press , 2012. , 77 p.
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1271
National Category
Medical and Health Sciences
Identifiers
URN: urn:nbn:se:liu:diva-72993ISBN: 978-91-7393-032-1 (print)OAI: oai:DiVA.org:liu-72993DiVA: diva2:464783
Public defence
2012-01-26, Berzeliussalen, Hälsouniversitetet, Campus US, Linköpings universitet, Linköping, 12:00 (English)
Opponent
Supervisors
Available from: 2011-12-14 Created: 2011-12-14 Last updated: 2011-12-19Bibliographically approved
List of papers
1. Genetic deletion of mPGES-1 accelerates intestinal tumorigenesis in APCMin/+ mice
Open this publication in new window or tab >>Genetic deletion of mPGES-1 accelerates intestinal tumorigenesis in APCMin/+ mice
Show others...
2008 (English)In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 372, no 1, 249-253 p.Article in journal (Refereed) Published
Abstract [en]

The induced synthesis of bioactive prostanoids downstream of cyclooxygenase-2 (COX-2) and prostaglandin H2 (PGH2) exerts a critical event in colorectal carcinogenesis. Here we demonstrate that APCMin/+ mice with genetic deletion of microsomal prostaglandin E synthase-1 (mPGES-1), which catalyses the terminal conversion of PGH2 into PGE2, surprisingly develop more and generally larger intestinal tumors than do mPGES-1 wild type littermates (mean number of tumors/intestine 80 vs. 38, p < 0.0005, mean tumor diameter 1.64 vs. 1.12 mm, p < 0.0005). No deviation regarding the expression of other PGE2 related enzymes (COX-1, COX-2, mPGES-2, cPGES, and 15-PGDH) or receptors (EP1-4) was obvious among the mPGES-1 deficient mice. PGE2 levels were suppressed in tumors of mPGES-1 deficient animals, but the concentrations of other PGH2 derived prostanoids were generally enhanced, being most prominent for TxA2 and PGD2. Thus, we hypothesise that a redirected synthesis towards other lipid mediators might (over)compensate for loss of mPGES-1/PGE2 during intestinal tumorigenesis. Nevertheless, our results question the suitability for mPGES-1 targeting therapy in the treatment or prevention of colorectal cancer. © 2008 Elsevier Inc. All rights reserved.

Keyword
6-Ketoprostaglandin F1 alpha/analysis Animals Cell Transformation, Neoplastic/*genetics/pathology Colorectal Neoplasms/*genetics/pathology Dinoprostone/analysis/*metabolism Female *Gene Deletion Intramolecular Oxidoreductases/*genetics Male Mice Mice, Mut
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-43256 (URN)10.1016/j.bbrc.2008.05.026 (DOI)73147 (Local ID)73147 (Archive number)73147 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2011-12-14Bibliographically approved
2. Association Between Adenomatosis Polyposis Coli Functional Status and Microsomal Prostaglandin E Synthase-1 Expression in Colorectal Cancer
Open this publication in new window or tab >>Association Between Adenomatosis Polyposis Coli Functional Status and Microsomal Prostaglandin E Synthase-1 Expression in Colorectal Cancer
Show others...
2009 (English)In: Molecular Carcinogenesis, ISSN 0899-1987, E-ISSN 1098-2744, Vol. 48, no 5, 401-407 p.Article in journal (Refereed) Published
Abstract [en]

Bioactive metabolites downstream of cyclooxygenase-2 (COX-2) generated prostaglandin H-2 (PGH(2)), in particular prostaglandin E-2 (PGE(2)), are thought to play critical roles during the development of colorectal tumors. Previous reports reveal that defects of the tumor suppressor adenomatosis polyposis coli (APC) contribute to COX-2 upregulation in colon tumor cells. We investigated whether a similar relation was present between APC functional status and the expression of microsomal prostaglandin E synthase-1 (mPGES-1), which acts downstream of COX-2 and catalyses the terminal conversion of PGH(2) into PGE(2). Surprisingly, mPGES-1 mRNA and protein levels were upregulated upon induction of a wild type-APC carrying vector in HT29 colon cancer cells, and downregulated following siRNA silencing of APC in HCT-116 cells. mPGES-1 was overall enhanced in human colorectal tumor specimens versus corresponding non-tumor mucosa and, in accordance with data on HT29 and HCT116 cells, higher levels of mPGES-1 were observed among tumors carrying wild type versus mutant APC. RNAi silencing of beta-catenin and luciferase assays regarding the mPGES-1 promoter region did not reveal a role for APC or beta-catenin/Tcf in controlling mPGES-1 gene transcription. However, RNA degradation assays in HT29 cells revealed a suppressed degradation of mPGES-1 in the presence of wild type APC, implying that mPGES-1 mRNA is stabilized in the APC wild type state. Collectively, we demonstrate a novel association between APC functional status and mPGFS-1 expression in colorectal tumor cells, being most likely related to reduced mPGES-1 mRNA degradation rate in the APC wild type state.

Keyword
cyclooxygenase 2, Prostaglandin E-2, beta-catenin, adenomatosis polyposis coli (APC), microsomal prostaglandin E synthase-1 (mPGES-1), colorectal cancer
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-18549 (URN)10.1002/mc.20500 (DOI)
Available from: 2009-06-01 Created: 2009-06-01 Last updated: 2011-12-14Bibliographically approved
3. Genetic variation in NFκB signaling pathway genes in colorectal cancer susceptibility and survival
Open this publication in new window or tab >>Genetic variation in NFκB signaling pathway genes in colorectal cancer susceptibility and survival
Show others...
(English)Manuscript (preprint) (Other academic)
Abstract [en]

PURPOSE: Variations in genes orchestrating inflammatory responses,  such as those being connected with NFκB and NLRP3 inflammasome signaling, are associated with chronic inflammatory bowel diseases, which are well-known risk factors for colorectal cancer (CRC). The purpose of this study was to investigate the association between genetic variation and alterations in genes involved in NFκB and NLRP3 inflammasome signaling and their possible influence on susceptibility and clinical outcome of colorectal cancer.

EXPERIMENTAL DESIGN: 344 CRC cases and 793 randomly selected healthy individuals from southeastern Sweden were examined with regard to seven polymorphisms in NFκB, TNFAIP3, NLRP3, CARD8 and TLR4 genes. Chi-square tests and multiple logistic regression analysis were used to test for associations between the SNPs and CRC susceptibility, while log-rank tests and Cox proportional hazard regression analysis were used to examine the association between the SNPs and CRC-specific survival. Gene expression assay and loss of heterozygosity analyzes of TNFAIP3 were carried out in a subset of tumors to assess its role as a potential tumor suppressor in CRC.

RESULTS: Adjusted for age, gender and polypoid/ulcerative CRC phenotype, a panel of heterozygous and mutant TNFAIP3 (rs6920220), mutant NFκB -94 ATTG ins/del and heterozygous NLRP3 (Q705K) genotypes were found to be associated with poorer survival in patients diagnosed with invasive CRC (aHR = 5.2 95% CI 2.5-10.9, P < 0.001). TNFAIP3 mRNA levels were significantly decreased in tumors compared to adjacent non-neoplastic mucosa (P < 0.0001) and LOH of 6q23.3, (TNFAIP3), was detected in 17% of cases, while only 2.5% of the investigated specimens displayed TNFAIP3 gene mutations.

CONCLUSIONS: A panel of the TNFAIP3 (rs6920220), NFκB -94 ATTG ins/del and NLRP3 (Q705K) polymorphisms are associated with poor survival in patients with advanced CRC and may be used as a prognostic marker. Experimental results indicate that TNFAIP3 may act as a tumor suppressor in CRC.

Keyword
Colorectal cancer, inflammation, inflammasome, polymorphism, TNFAIP3
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-72990 (URN)
Available from: 2011-12-14 Created: 2011-12-14 Last updated: 2011-12-14Bibliographically approved
4. The Notch-2 Gene Is Regulated by Wnt Signaling in Cultured Colorectal Cancer Cells
Open this publication in new window or tab >>The Notch-2 Gene Is Regulated by Wnt Signaling in Cultured Colorectal Cancer Cells
Show others...
2011 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, no 3, 0017957- p.Article in journal (Refereed) Published
Abstract [en]

Background: Notch and Wnt pathways are key regulators of intestinal homeostasis and alterations in these pathways may lead to the development of colorectal cancer (CRC). In CRC the Apc/beta-catenin genes in the Wnt signaling pathway are frequently mutated and active Notch signaling contributes to tumorigenesis by keeping the epithelial cells in a proliferative state. These pathways are simultaneously active in proliferative adenoma cells and a crosstalk between them has previously been suggested in normal development as well as in cancer. Principal Findings: In this study, in silico analysis of putative promoters involved in transcriptional regulation of genes coding for proteins in the Notch signaling pathway revealed several putative LEF-1/TCF sites as potential targets for beta-catenin and canonical Wnt signaling. Further results from competitive electrophoretic mobility-shift assay (EMSA) studies suggest binding of several putative sites in Notch pathway gene promoters to in vitro translated beta-catenin/Lef-1. Wild type (wt)-Apc negatively regulates beta-catenin. By induction of wt-Apc or beta-catenin silencing in HT29 cells, we observed that several genes in the Notch pathway, including Notch-2, were downregulated. Finally, active Notch signaling was verified in the Apc(Min/+) mouse model where Hes-1 mRNA levels were found significantly upregulated in intestinal tumors compared to normal intestinal mucosa. Luciferase assays showed an increased activity for the core and proximal Notch-2 promoter upon co-transfection of HCT116 cells with high expression recombinant Tcf-4, Lef-1 or beta-catenin. Conclusions: In this paper, we identified Notch-2 as a novel target for beta-catenin-dependent Wnt signaling. Furthermore our data supports the notion that additional genes in the Notch pathway might be transcriptionally regulated by Wnt signaling in colorectal cancer.

Place, publisher, year, edition, pages
Public Library of Science (PLoS), 2011
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-67155 (URN)10.1371/journal.pone.0017957 (DOI)000288545100048 ()
Note
Original Publication: Jonas Ungerbäck, Nils Elander, John Grunberg, Mikael Sigvardsson and Peter Söderkvist, The Notch-2 Gene Is Regulated by Wnt Signaling in Cultured Colorectal Cancer Cells, 2011, PLOS ONE, (6), 3, 0017957. http://dx.doi.org/10.1371/journal.pone.0017957 Licensee: Public Library of Science (PLoS) http://www.plos.org/ Available from: 2011-04-01 Created: 2011-04-01 Last updated: 2017-12-11Bibliographically approved

Open Access in DiVA

Inflammation and Intestinal Homeostasis-Associated Genes in Colorectal Cancer(1151 kB)11084 downloads
File information
File name FULLTEXT01.pdfFile size 1151 kBChecksum SHA-512
83af25040791e44d6d46d2e1bfabe160bbf56e623c7bb7218f0161b797a5a6d6628b11a6ca9b7748193fa6811a3a56069be00d9d2910d961220203eba7e6544b
Type fulltextMimetype application/pdf
omslag(832 kB)113 downloads
File information
File name COVER01.pdfFile size 832 kBChecksum SHA-512
240408d8cfaaad8934c0f29d7d8bb87400d5b43c9e21de94d09667d302c60aa8acd0346b7314f87bc093430a78c75a0442db015a153137e210a70ab312c86b20
Type coverMimetype application/pdf

Authority records BETA

Ungerbäck, Jonas

Search in DiVA

By author/editor
Ungerbäck, Jonas
By organisation
Cell BiologyFaculty of Health Sciences
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 11084 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 727 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf