Colorectal cancer (CRC) screening in the form of self-sampling enhances participation and early cancer detection. However, CRC screening participation in Sweden is marked by inequality. Moreover, individuals are relatively uninformed about screening procedures, with existing informational channels all exhibiting various limitations. Hence, this project was initiated in collaboration with KI and KTH to develop a digital decision aid for individuals called into CRC screening. This study aims to mark an initial stage of development, with the overarching goal being to improve CRC screening participation rates and support informed decision making aligned with patient values and preferences. Using an approach rooted in the shared decision-making (SDM) model, the study investigates user attitudes and preferences concerning health, digital healthcare services and cancer screening through conducting semi-structured interviews and a thematic analysis. These insights inform user requirements, which are integrated with stakeholder requirements and the current informational landscape to shape the digital decision aid’s information architecture and design. The research identifies various challenges and opportunities for the development of the digital decision aid in a Swedish context, underscoring the importance of adapting the decision aid to user needs and preferences. In subsequent stages of development, the prototype produced by this study should be evaluated through usability testing, and further user research should be conducted to generate more specific user requirements concerning visual and interactional elements.

Yes / There remains an unmet need for safe and cost-effective adjunctive treatment of advanced colorectal cancer (CRC). The omega-3 polyunsaturated fatty acid eicosapentaenoic acid (EPA) is safe, well-tolerated and has anti-inflammatory as well as antineoplastic properties. A phase 2 randomised trial of preoperative EPA free fatty acid 2 g daily in patients undergoing surgery for CRC liver metastasis showed no difference in the primary endpoint (histological tumour proliferation index) compared with placebo. However, the trial demonstrated possible benefit for the prespecified exploratory endpoint of postoperative disease-free survival. Therefore, we tested the hypothesis that EPA treatment, started before liver resection surgery (and continued postoperatively), improves CRC outcomes in patients with CRC liver metastasis. Methods and analysis: The EPA for Metastasis Trial 2 trial is a randomised, double-blind, placebo-controlled, phase 3 trial of 4 g EPA ethyl ester (icosapent ethyl (IPE; Vascepa)) daily in patients undergoing liver resection surgery for CRC liver metastasis with curative intent. Trial treatment continues for a minimum of 2 years and maximum of 4 years, with 6monthly assessments, including quality of life outcomes, as well as annual clinical record review after the trial intervention. The primary endpoint is CRC progression-free survival. Key secondary endpoints are overall survival, as well as the safety and tolerability of IPE. A minimum 388 participants are estimated to provide 247 CRC progression events during minimum 2-year follow-up, allowing detection of an HR of 0.7 in favour of IPE, with a power of 80% at the 5% (two sided) level of significance, assuming drop-out of 15%. Ethics and dissemination: Ethical and health research authority approval was obtained in January 2018. All data will be collected by 2025. Full trial results will be published in 2026. Secondary analyses of health economic data, biomarker studies and other translational work will be published subsequently. Trial registration number NCT03428477. / The EMT2 trial is funded by Yorkshire Cancer Research (L387) and is sponsored by the University of Leeds. The EMT2 biospecimen collection is funded by the National Institutes of Health (1R01CA243454-01A1) and is sponsored by the University of Leeds ( governance-ethics@ leeds. ac. uk). Both studies have been adopted to the NIHR Clinical Research Network (CRN) Portfolio (CPMS ID 34700 and 47372, respectively) and have benefited from CRN research staff support.

Yes / One of the main obstacles to therapeutic success in colorectal cancer (CRC) is the development of acquired resistance to treatment with drugs such as 5-fluorouracil (5-FU). Whilst some resistance mechanisms are well known, it is clear from the stasis in therapy success rate that much is still unknown. Here, a proteomics approach is taken towards identification of candidate proteins using 5-FU-resistant sublines of human CRC cell lines generated in house. Using a multiplexed stable isotope labelling with amino acids in cell culture (SILAC) strategy, 5-FU-resistant and equivalently passaged sensitive cell lines were compared to parent cell lines by growing in Heavy medium with 2D liquid chromatography and Orbitrap Fusion™ Tribrid™ Mass Spectrometry analysis. Among 3003 commonly quantified proteins, six (CD44, APP, NAGLU, CORO7, AGR2, PLSCR1) were found up-regulated, and six (VPS45, RBMS2, RIOK1, RAP1GDS1, POLR3D, CD55) down-regulated. A total of 11 of the 12 proteins have a known association with drug resistance mechanisms or role in CRC oncogenesis. Validation through immunodetection techniques confirmed high expression of CD44 and CD63, two known drug resistance mediators with elevated proteomics expression results. The information revealed by the sensitivity of this method warrants it as an important tool for elaborating the complexity of acquired drug resistance in CRC. / Sadr ul-Shaheed and the University of Bradford Proteomics Facility were supported by Yorkshire Cancer Research, UK (Cancer Medicine Discovery II, grant B381PA).

BACKGROUND: Genome-wide association studies (GWAS) have identified single nucleotide polymorphisms (SNPs) associated with diseases of the colon including inflammatory bowel diseases (IBD) and colorectal cancer (CRC). However, the functional role of many of these SNPs is largely unknown and tissue-specific resources are lacking. Expression quantitative trait loci (eQTL) mapping identifies target genes of disease-associated SNPs. This study provides a comprehensive eQTL map of distal colonic samples obtained from 40 healthy African Americans and demonstrates their relevance for GWAS of colonic diseases. RESULTS: 8.4 million imputed SNPs were tested for their associations with 16,252 expression probes representing 12,363 unique genes. 1,941 significant cis-eQTL, corresponding to 122 independent signals, were identified at a false discovery rate (FDR) of 0.01. Overall, among colon cis-eQTL, there was significant enrichment for GWAS variants for IBD (Crohn's disease [CD] and ulcerative colitis [UC]) and CRC as well as type 2 diabetes and body mass index. ERAP2, ADCY3, INPP5E, UBA7, SFMBT1, NXPE1 and REXO2 were identified as target genes for IBD-associated variants. The CRC-associated eQTL rs3802842 was associated with the expression of C11orf93 (COLCA2). Enrichment of colon eQTL near transcription start sites and for active histone marks was demonstrated, and eQTL with high population differentiation were identified. CONCLUSIONS: Through the comprehensive study of eQTL in the human colon, this study identified novel target genes for IBD- and CRC-associated genetic variants. Moreover, bioinformatic characterization of colon eQTL provides a tissue-specific tool to improve understanding of biological differences in diseases between different ethnic groups.

Since the initial description of cancer stem cells (CSCs) as a self-renewing subpopulation of malignant cells with tumor-initiating capacity, a growing body of evidence has supported the existence of CSCs in virtually every tumor type. Our previous work in colorectal cancer has identified the transcription factor CDX1 as a key regulator of colorectal CSC differentiation. CDX1 expression is frequently lost in colorectal cancer, resulting in more aggressive, poorly differentiated tumors with higher proportions of CSCs. Many miRNAs have been implicated in tumor suppression and carcinogenesis, but the roles of miRNAs in differentiation, particularly in colorectal cancer, remain poorly understood. We began by identifying miRNAs downstream of CDX1 by using high-throughput small-RNA sequencing to profile miRNA expression in two pairs of colorectal cancer cell lines with stable CDX1 overexpression or knockdown. Validation of candidates identified by RNAseq in a larger cell line panel revealed miR-215 to be most significantly correlated with CDX1 expression. ChIP-qPCR and promoter reporter assays confirmed that CDX1 directly transactivates miR-215 transcription. MiR-215 is depleted in FACS-enriched CSCs compared to unsorted samples. Overexpression of miR-215 in poorly-differentiated, highly clonogenic cell lines causes growth arrest and a dramatic decrease in colony formation. miR-215 knockdown using a miRNA sponge causes an increase in clonogenicity and impairs differentiation in CDX1-high cell lines. Indeed, the effects of CDX1 expression on both gene expression and colony morphology can be attenuated by miR-215 inhibition, indicating that miR-215 is a functional mediator of CDX1. Microarray studies following miR-215 overexpression indicate that miR-215 induces terminal differentiation-associated growth arrest, due in part to direct silencing of BMI1 expression and de-repression of BMI1 target genes including CDKN1A. Our work situates miR-215 as a link between CDX1 expression and BMI1 repression that governs differentiation in colorectal cancer. We further characterize another miRNA-transcription factor axis in colorectal cancer, and we identify the novel miR-3189-3p as a potent effector of cell death with potential therapeutic implications.

Das Ansprechen primärer Rektumkarzinome auf eine präoperative Radiochemotherapie ist äußerst heterogen. Resistente Karzinome stellen aufgrund der schlechteren Prognose ein großes klinisches Problem dar. Ziel ist daher eine Individualisierung der Therapie und die Identifikation neuer therapeutischer Angriffspunkte, um resistente Tumoren für die Therapie zu sensibilisieren. In vorangegangenen Studien konnte gezeigt werden, dass zwischen Respondern und Nonrespondern TCF4, ein Transkriptionsfaktor des Wnt/β-Catenin-Signalwegs, differentiell exprimiert ist. Zudem führt die Herunterregulation von TCF4 in kolorektalen Karzinomzelllinien zu einer Radiotherapiesensibilisierung. Um zu untersuchen, ob es sich um eine TCF4-spezifische Beobachtung handelt oder ob der Wnt/β-Catenin-Signalweg Radiotherapieresistenz vermittelt, wurde dieser Signalweg in den Zelllinien SW480, SW837, LS1034 und RPE inhibiert. Anschließend wurde die Radiotherapieresistenz der Zellen untersucht. Die Inhibition des Wnt/β-Catenin-Signalwegs mittels siRNA gegen β-Catenin führte zu einer signifikanten Radiotherapiesensibilisierung von SW480, SW837 und LS1034. Die Behandlung von kolorektalen Karzinomzelllinien und der Normalzelllinie RPE mit dem kleinmolekularen Wnt/β-Catenin-Signalweg-Inhibitor XAV939 führte zum Teil zu einer Radiotherapiesensibilisierung. Insgesamt scheint der Wnt/β-Catenin-Signalweg eine entscheidende Rolle in der Entstehung der Radio(chemo)resistenz zu spielen und stellt somit ein potentielles therapeutisches Ziel für zukünftige Therapieansätze des Rektumkarzinoms dar. Zudem wurde dem Wnt/β-Catenin-Signalweg eine weitere biologische Bedeutung zugeordnet. Ziel zukünftiger Bemühungen ist die weitere Validierung dieser Ergebnisse, die Aufdeckung der zugrunde liegenden Mechanismen und die Übertragung in ein in-vivo-Modell.

Changes in the human gastrointestinal microbiome are associated with several diseases. To infer causality, experiments in representative models are essential, but widely used animal models exhibit limitations. Here we present a modular, microfluidics-based model (HuMiX, human-microbial crosstalk), which allows co-culture of human and microbial cells under conditions representative of the gastrointestinal human-microbe interface. We demonstrate the ability of HuMiX to recapitulate in vivo transcriptional, metabolic and immunological responses in human intestinal epithelial cells following their co-culture with the commensal Lactobacillus rhamnosus GG (LGG) grown under anaerobic conditions. In addition, we show that the co-culture of human epithelial cells with the obligate anaerobe Bacteroides caccae and LGG results in a transcriptional response, which is distinct from that of a co-culture solely comprising LGG. HuMiX facilitates investigations of host-microbe molecular interactions and provides insights into a range of fundamental research questions linking the gastrointestinal microbiome to human health and disease.

In the present investigation peripheral blood lymphocytes from patients with inflammatory bowel disease (IBD) and different cancer states were treated with various agents and compared with lymphocytes from healthy control individuals (HCI) treated in the same way and measured in the Comet assay. For inflammatory bowel disease, patient's responses in IBD patients treated with H2O2 were higher than in HCI and Crohn's patients (CD) were found to have higher responses than Ulcerative colitis (UC) patients. The responses for all IBD and HCI were all reduced in the presence of chaga mushroom extract which behaved in an antioxidant manner. A second group of IBD patients were treated with the heterocyclic amine (food mutagen), IQ and H2O2 and responses were reduced in the presence of the flavonoids, quercetin and epicatechin and compared with HCI similarity treated. In all cells responses were reduced with flavonoids and again CD had higher responses than the UC patients and IBD patients higher than HCI. The responses with CD and UC were that confirmed in two independent studies with IBD, one with chaga mushroom extract and the other with flavonoids. Peripheral lymphocytes from malignant melanoma and suspected melanoma patients and colon cancer and polyposis patients were compared to the lymphocytes from HCI and treated with UVA. There were differential sensitivities when measured in the micronucleus and Comet assays. The cancer patients had higher responses than those in the precancerous states and they in turn were higher than responses in HCI. In all the studies, untreated baseline DNA damage values were also higher in IBD and cancer patients and pre-cancerous patients than HCIs. This would suggest that baseline frequencies of different diseases compared to controls could be an important biomarker in the diagnosis of pre-cancers and early stage cancers. Also peripheral lymphocytes are a useful surrogate for cancers and pre-cancerous disease states since, blood is present in all organs and tissues and DNA is basically the same in all cells.

Background: Colorectal cancer (CRC) is the third most common cancer in men and the second most common in women worldwide. Adenomas can be precursors to CRC, and inflammatory bowel disease (IBD) can present with the same symptoms as CRC. The majority of patients with CRC initially consult primary care. Symptoms associated with CRC are also common among primary care patients, but seldom caused by any significant disease. Reliable diagnostic aids would be helpful in deciding which patients to refer. Faecal immunochemical tests (FITs) are commonly used for this purpose in primary care in Sweden, but there is little evidence to support this use. Faecal calprotectin (FC) has been suggested as an additional test. Aim: To explore how doctors in primary care investigate patients with suspected CRC, the value of FITs, symptoms and presence of anaemia in diagnosing CRC and adenomas in primary care, and whether FC tests could contribute to diagnosis. Methods: Three studies (1-3) were carried out in Region Jämtland Härjedalen, Sweden. There was no screening programme for CRC. We used a point of care qualitative dip-stick 3-sample FIT with a cut-off of 25-50μg haemoglobin/g faeces, and a calprotectin enzyme-linked immunosorbent assay (ELISA) test with a cut-off of 100 μg/g faeces. 1: A retrospective, population-based study including all patients diagnosed with CRC or adenomas with high-grade dysplasia (HGD) during the period 2005-2009 that initially consulted primary care. Symptoms, FIT results, anaemia and time to diagnosis were retrieved from medical records. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated from FIT results at the region’s health centres 2008- 2009. (Paper I.) 2: A prospective cohort study including consecutive patients where primary care doctors requested FITs and/or FC tests, at four health centres, from 30 Jan 2013 to 31 May 2014. FITs, FC tests, haemoglobin and iron deficiency tests were analysed; patients and doctors answered questionnaires about symptoms. Patients were examined with bowel imaging or followed for two years. Findings of CRC, adenomas with HGD, adenomas with low grade dysplasia (LGD) ≥1 cm and IBD were registered. (Papers II and III.) 3: A qualitative study of interviews with eleven primary care doctors. We explored what made them suspect CRC, and their practices regarding investigation and referral with particular attention to their use of FITs. Qualitative content analysis with an inductive approach was used for the analysis. (Paper IV.) Results: 1: Paper I: Of 495 patients 323 (65.3%) started the investigation in primary care. FITs were analysed in 215. In 23 cases with CRC, FITs were negative; 15 (65.2%) had anaemia. In 33 cases with CRC, FITs were performed due to asymptomatic anaemia; 10 (30.3%) had negative FITs. The time from start of investigation, to the diagnosis of CRC or adenomas with HGD, was significantly longer for patients with negative FITs. 2: 377 patients (9 diagnosed with CRC, 10 with IBD) were included. Paper II: Concordance of positive answers about symptoms from patients and doctors was generally low. Rectal bleeding (recorded by 43.5% of patients and 25.6% of doctors) was the only symptom related to CRC and IBD. The FIT showed a better PPV than rectal bleeding for CRC and IBD. When patients recorded rectal bleeding, the FIT had a PPV of 22.6% and a NPV of 98.9% for CRC and IBD. Paper III: The best test for detecting CRC and IBD was the combination of a positive FIT and/or anaemia with a sensitivity, specificity, PPV and NPV of 100%, 61.7%, 11.7% and 100% respectively. The FC test had no additional value to the FIT alone. The sensitivity, specificity, PPV and NPV of the FIT for CRC in study 1 was estimated at 88.4%, 73.3%, 6.2% and 99.7% respectively. In study 2, corresponding figures were 88.9%, 67.4%, 6.3% and 99.6% respectively. 3: Paper IV: We identified four categories: “Careful listening – with awareness of the pit-falls”, “tests can help – the FIT can also complicate the diagnosis”, “to refer or not to refer – safety margins are necessary”, and “growing more confident – but also more humble”. All doctors had found their own way to handle FIT results in the absence of guidelines. Conclusion: The diagnostic process when suspecting CRC can be described as navigating uncertain waters with safety margins. FITs were often used by primary care doctors but with considerable variations in interpretation and handling of results. Rectal bleeding was the only symptom related to CRC and IBD, but the FIT showed a better PPV than rectal bleeding. The combination of a negative FIT and no anaemia may be useful as a rule-out test when CRC is suspected in primary care, and this potentially also applies when patients present with rectal bleeding. Further studies are needed to confirm this and to determine the optimal FIT cut-off value for this use.

The cancer stem cell (CSC) model of carcinogenesis and progression posits that within a tumor lies a subpopulation of cells that solely possess the ability to initiate a tumor and to differentiate into tumor cell lineages. Although the behavior of such cells is known, the challenge is to identify factors that characterize the CSC subpopulation. In this thesis, cell lines were identified that, when grown in three-dimensions, gave rise to organized colonies containing lumens originating from differentiating cells (“lumen lines”) and to densely-packed, spherical colonies originating from non-differentiating cells (“dense lines”). A microarray comparison of the pair identified genes upregulated in dense lines, including CD55 and BMI1, and in lumen lines, including CDX1 (Chapter 3). CD55 was used to isolate CD55high CSCs via flow cytometry that are able to self-renew, differentiate, initiate more colonies, proliferate more rapidly and exhibit an increased G2/M cell cycle population as opposed to unfractionated cells. Furthermore, the CD55high cells were able to give rise to more differentiated, lumen colonies in vitro, indicating that CD55 enriches for cells possessing a capacity to differentiate, and were able to enrich the CD24highCD44high putative CSC population further (Chapter 4). CDNA induction of BMI1 and CDX1 expression led to increased clonogenicity/proliferation and decreased clonogenicity/proliferation, respectively, and incorporation of a CDX1 reporter construct into the SW1222 cell line identified CDX1+ cells as a low-expressing population of CD55 (Chapter 5). Finally, co-culture of cell lines in an in vivo-like environment with intestinal myofibroblasts promoted the CSC population by enhancing clonogenicity, proliferation and expression of CD55 (Chapter 6). The results of this thesis implicate CD55 as a potent marker of colorectal cancer stemness, link the expression of BMI1 and CDX1 to cancer stemness and differentiation, respectively, and identify a role for the in vivo stem cell niche in maintaining the CSC population.