Mouse models of colorectal cancer as preclinical models.

In this review, we discuss the application of mouse models to the identification and pre-clinical validation of novel therapeutic targets in colorectal cancer, and to the search for early disease biomarkers. Large-scale genomic, transcriptomic and epigenomic profiling of colorectal carcinomas has led to the identification of many candidate genes whose direct contribution to tumourigenesis is yet to be defined; we discuss the utility of cross-species comparative 'omics-based approaches to this problem. We highlight recent progress in modelling late-stage disease using mice, and discuss ways in which mouse models could better recapitulate the complexity of human cancers to tackle the problem of therapeutic resistance and recurrence after surgical resection.REM, SJAB, MJA and DJA are funded by Cancer Research UK.This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1002/bies.20150003

An analysis of SARS-CoV-2 cell entry genes identifies the intestine and colorectal cancer as susceptible tissues.

SARS-CoV-2 is the causative agent for the COVID-19 pandemic. COVID-19 has necessitated rapid changes in surgical practice and organisation through both the initial peak and ongoing recovery period 1. SARS-CoV-2 infects cells by interacting with the host cell surface protein ACE2 and utilises TMPRSS2 in viral spike protein priming to facilitate cell entry (Fig. 1a) 2. Whilst COVID-19 is predominantly a respiratory disease approximately 15% of patients have concurrent gastrointestinal symptoms 3. SARS-CoV-2 RNA and live virus have been identified in stool from COVID-19 patients and SARS-CoV-2 readily infects intestinal organoids 4-6. Despite these circumstantial data, gastrointestinal transmission has not yet been formally confirmed. Cancers commonly express different genes from the tissue of origin and it is largely unexplored whether tumours can be infected with SARS-CoV-2. We sought to explore the expression of ACE2 and TMPRSS2 in large publicly available normal tissue and pan-cancer expression data sets to understand whether levels of these genes identify susceptible tissues.SJAB is supported by an Advanced Clinician Scientist Fellowship grant from Cancer Research UK C14094/A27178; and core funding from Wellcome and MRC to the Wellcome-MRC Cambridge Stem Cell Institute

Improving Radiotherapy in Immunosuppressive Microenvironments by Targeting Complement Receptor C5aR1

An immunosuppressive microenvironment causes poor tumor T cell infiltration and is associated with reduced patient overall survival in colorectal cancer. How to improve treatment responses in these tumors is still a challenge. Using an integrated screening approach to identify cancer-specific vulnerabilities, we identified complement receptor C5aR1 as a druggable target, which when inhibited improved radiotherapy, even in tumors displaying immunosuppressive features and poor CD8+ T cell infiltration. While C5aR1 is well-known for its role in the immune compartment, we found that C5aR1 is also robustly expressed on malignant epithelial cells, highlighting potential tumor cell-specific functions. C5aR1 targeting resulted in increased NF-κB-dependent apoptosis specifically in tumors and not normal tissues, indicating that, in malignant cells, C5aR1 primarily regulated cell fate. Collectively, these data revealed that increased complement gene expression is part of the stress response mounted by irradiated tumors and that targeting C5aR1 could improve radiotherapy, even in tumors displaying immunosuppressive features

Itraconazole perturbs colorectal cancer dormancy through SUFU-mediated WNT inhibition.

Cancer cell dormancy is an important source of treatment failure. We studied the molecular characteristics and functional behaviour of dormant colorectal cancer cells finding them to be a differentiated yet plastic population. Organoid drug screening identified itraconazole perturbs dormancy through non-canonical hedgehog signalling effects on the WNT pathway

Itraconazole targets cell cycle heterogeneity in colorectal cancer.

Cellular dormancy and heterogeneity in cell cycle length provide important explanations for treatment failure after adjuvant therapy with S-phase cytotoxics in colorectal cancer (CRC), yet the molecular control of the dormant versus cycling state remains unknown. We sought to understand the molecular features of dormant CRC cells to facilitate rationale identification of compounds to target both dormant and cycling tumor cells. Unexpectedly, we demonstrate that dormant CRC cells are differentiated, yet retain clonogenic capacity. Mouse organoid drug screening identifies that itraconazole generates spheroid collapse and loss of dormancy. Human CRC cell dormancy and tumor growth can also be perturbed by itraconazole, which is found to inhibit Wnt signaling through noncanonical hedgehog signaling. Preclinical validation shows itraconazole to be effective in multiple assays through Wnt inhibition, causing both cycling and dormant cells to switch to global senescence. These data provide preclinical evidence to support an early phase trial of itraconazole in CRC

Myoferlin:a potential marker of response to radiotherapy and survival in locally advanced rectal cancer

PURPOSE: Patients with locally advanced rectal cancer often require neo-adjuvant chemoradiotherapy to downstage the disease, but the response is variable with no predictive biomarkers. We have previously revealed through proteomic profiling that myoferlin is associated with response to radiotherapy. The aims of this study were to further validate this finding and explore the potential for myoferlin to act as a prognostic and/or therapeutic target.MATERIALS AND METHODS: Immunohistochemical analysis of a tissue microarray for 111 patients was used to validate the initial proteomic findings. Manipulation of myoferlin was achieved using siRNA, a small molecular inhibitor (wj460) and a CRISPR-Cas9 knockout cell line. Radiosensitisation following treatment was assessed using 2D clonogenic assays, 3D spheroid models and patient derived organoids. Underlying mechanisms were investigated using electrophoresis, immunofluorescence and immunoblotting.RESULTS: Analysis of both the diagnostic biopsy and tumour resection samples confirmed that low myoferlin expression correlated with a good response to neoadjuvant LCRT. High myoferlin expression was associated with spread to local lymph nodes and worse 5-year survival (p = 0.01, HR 3.5, 95%CI [1.27, 10.04]). This was externally validated using the S:CORT database. Quantification of myoferlin using immunoblotting in immortalised colorectal cancer cell lines and organoids demonstrated that high myoferlin expression was associated with increased radioresistance. Biological and pharmacological manipulation of myoferlin resulted in significantly increased radiosensitivity across all cell lines in 2D and 3D models. Following irradiation, myoferlin knockdown cells had a significantly impaired ability to repair DNA double strand breaks. This appeared to be mediated via non-homologous end-joining.CONCLUSIONS: We have confirmed that high expression of myoferlin in rectal cancer is associated with poor response to neoadjuvant therapy and worse long-term survival. Furthermore, the manipulation of myoferlin led to increased radiosensitivity in vitro. This suggests that myoferlin could be targeted to enhance the sensitivity of rectal cancer patients to radiotherapy and further work is required.</p

Mutational landscape of normal epithelial cells in Lynch Syndrome patients.

Lynch Syndrome (LS) is an autosomal dominant disease conferring a high risk of colorectal cancer due to germline heterozygous mutations in a DNA mismatch repair (MMR) gene. Although cancers in LS patients show elevated somatic mutation burdens, information on mutation rates in normal tissues and understanding of the trajectory from normal to cancer cell is limited. Here we whole genome sequence 152 crypts from normal and neoplastic epithelial tissues from 10 LS patients. In normal tissues the repertoire of mutational processes and mutation rates is similar to that found in wild type individuals. A morphologically normal colonic crypt with an increased mutation burden and MMR deficiency-associated mutational signatures is identified, which may represent a very early stage of LS pathogenesis. Phylogenetic trees of tumour crypts indicate that the most recent ancestor cell of each tumour is already MMR deficient and has experienced multiple cycles of clonal evolution. This study demonstrates the genomic stability of epithelial cells with heterozygous germline MMR gene mutations and highlights important differences in the pathogenesis of LS from other colorectal cancer predisposition syndromes

Inherited MUTYH mutations cause elevated somatic mutation rates and distinctive mutational signatures in normal human cells.

Cellular DNA damage caused by reactive oxygen species is repaired by the base excision repair (BER) pathway which includes the DNA glycosylase MUTYH. Inherited biallelic MUTYH mutations cause predisposition to colorectal adenomas and carcinoma. However, the mechanistic progression from germline MUTYH mutations to MUTYH-Associated Polyposis (MAP) is incompletely understood. Here, we sequence normal tissue DNAs from 10 individuals with MAP. Somatic base substitution mutation rates in intestinal epithelial cells were elevated 2 to 4-fold in all individuals, except for one showing a 31-fold increase, and were also increased in other tissues. The increased mutation burdens were of multiple mutational signatures characterised by C > A changes. Different mutation rates and signatures between individuals are likely due to different MUTYH mutations or additional inherited mutations in other BER pathway genes. The elevated base substitution rate in normal cells likely accounts for the predisposition to neoplasia in MAP. Despite ubiquitously elevated mutation rates, individuals with MAP do not display overt evidence of premature ageing. Thus, accumulation of somatic mutations may not be sufficient to cause the global organismal functional decline of ageing

FXR inhibition may protect from SARS-CoV-2 infection by reducing ACE2.

Preventing SARS-CoV-2 infection by modulating viral host receptors, such as angiotensin-converting enzyme 2 (ACE2)1, could represent a new chemoprophylactic approach for COVID-19 that complements vaccination2,3. However, the mechanisms that control the expression of ACE2 remain unclear. Here we show that the farnesoid X receptor (FXR) is a direct regulator of ACE2 transcription in several tissues affected by COVID-19, including the gastrointestinal and respiratory systems. We then use the over-the-counter compound z-guggulsterone and the off-patent drug ursodeoxycholic acid (UDCA) to reduce FXR signalling and downregulate ACE2 in human lung, cholangiocyte and intestinal organoids and in the corresponding tissues in mice and hamsters. We show that the UDCA-mediated downregulation of ACE2 reduces susceptibility to SARS-CoV-2 infection in vitro, in vivo and in human lungs and livers perfused ex situ. Furthermore, we reveal that UDCA reduces the expression of ACE2 in the nasal epithelium in humans. Finally, we identify a correlation between UDCA treatment and positive clinical outcomes after SARS-CoV-2 infection using retrospective registry data, and confirm these findings in an independent validation cohort of recipients of liver transplants. In conclusion, we show that FXR has a role in controlling ACE2 expression and provide evidence that modulation of this pathway could be beneficial for reducing SARS-CoV-2 infection, paving the way for future clinical trials

FXR inhibition may protect from SARS-CoV-2 infection by reducing ACE2.

Acknowledgements: We thank the European Association for the Study of the Liver (EASL) and the American Association for the Study of Liver Disease (AASLD) for supporting the COVID-Hep and SECURE-Liver registries; S. Marciniak and P. J. Lehner for comments and feedback on the manuscript; I. Goodfellow for providing the viral isolate; M. Wills and S. Clare for all their work ensuring a safe CL-3 working environment; C. Cormie for general lab support; the NIHR Cambridge BRC Cell Phenotyping Hub for their help with flow cytometry and processing of samples; the building staff of the Jeffrey Cheah Biomedical Centre for maintaining the institute open and safe during the period of lockdown; K. Füssel for coordinating the volunteer study and sample collection at the University Medical Centre Hamburg-Eppendorf; J. Hails, K.-I. Nikitopoulou and A. Ford for collecting blood samples; M. Colzani for advising on flow cytometry; A. Wiblin for advising on antibodies; and the Cambridge Biorepository for Translational Medicine for the provision of human tissue used in the study. T.B. was supported by an EASL Juan Rodès PhD fellowship. F.S. was supported by a UKRI Future Leaders fellowship, the Evelyn trust, an NIHR Clinical Lectureship, the Academy of Medical Sciences Starter Grant for Clinical Lecturers, the Addenbrooke’s Charitable Trust and the Rosetrees Trust. In addition, the F.S. laboratory is supported by the Cambridge University Hospitals National Institute for Health Research Biomedical Research Centre and the core support grant from the Wellcome Trust and Medical Research Council (MRC) of the Wellcome–Medical Research Council Cambridge Stem Cell Institute. The L.V. laboratory is funded by the ERC advanced grant New-Chol, the Cambridge University Hospitals National Institute for Health Research Biomedical Research Centre and the core support grant from the Wellcome Trust and MRC of the Wellcome–Medical Research Council Cambridge Stem Cell Institute. M.M., S.F. and G.D. are funded by the NIHR Cambridge Biomedical Research Centre and NIHR AMR Research Capital Funding Scheme (NIHR200640). The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care. V.L.M. was funded by an MRC Clinical Research Training Fellowship. G.F.M. was funded by a post-doctoral fellowship from the National Institute for Health Research (NIHR) Rare Diseases–Translational Research Collaboration (RD-TRC) and by an MRC Clinical Academic Research Partnership (CARP) award. The UK-PBC Nested Cohort study was funded by an MRC Stratified Medicine award (MR/L001489/1). C.J.R.I. was supported by the Medical Research Council (MC_UU_12014). T.M. is funded by a Wellcome Trust Clinical Research Training Fellowship (102176/B/13/Z). The A.P.D. laboratory was supported by BHF TG/18/4/33770, Wellcome Trust 203814/Z/16/A and Addenbrooke’s Charitable Trust. The COVID-Hep.net registry was supported by the European Association for the Study of the Liver (EASL) and the SECURE-Liver registry was supported by the American Association for the Study of Liver Disease (AASLD). The lung perfusion experiment was supported by the National Institute for Health Research Blood and Transplant Research Unit (NIHR BTRU) in Organ Donation and Transplantation at Newcastle University and the University of Cambridge in partnership with NHS Blood and Transplant (NHSBT). The views expressed are those of the author(s) and not necessarily those of the NIHR, the Department of Health and Social Care or NHSBT. G.B. is funded by the European Reference Network for Hepatological Diseases (ERN RARE LIVER). A.O. acknowledges funding for preclinical research on treatment and prevention of COVID-19 from Unitaid (2020-38-LONGEVITY), the Engineering and Physical Sciences Research Council (EPSRC; EP/R024804/1), the Wellcome Trust (222489/Z/21/Z) and UK Research and Innovation (UKRI; BB/W010801/1). N.J.M. acknowledges funding from the MRC (CSF ref. MR/P008801/1 to N.J.M.), NHSBT (grant ref. WPA15-02 to N.J.M.) and Addenbrooke’s Charitable Trust (grant ref. to 900239 N.J.M.). This research was funded in whole, or in part, by the Wellcome Trust (203151/Z/16/Z, 203151/A/16/Z) and the UKRI Medical Research Council (MC_PC_17230). For the purpose of open access, the author has applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission.Preventing SARS-CoV-2 infection by modulating viral host receptors, such as angiotensin-converting enzyme 2 (ACE2)1, could represent a new chemoprophylactic approach for COVID-19 that complements vaccination2,3. However, the mechanisms that control the expression of ACE2 remain unclear. Here we show that the farnesoid X receptor (FXR) is a direct regulator of ACE2 transcription in several tissues affected by COVID-19, including the gastrointestinal and respiratory systems. We then use the over-the-counter compound z-guggulsterone and the off-patent drug ursodeoxycholic acid (UDCA) to reduce FXR signalling and downregulate ACE2 in human lung, cholangiocyte and intestinal organoids and in the corresponding tissues in mice and hamsters. We show that the UDCA-mediated downregulation of ACE2 reduces susceptibility to SARS-CoV-2 infection in vitro, in vivo and in human lungs and livers perfused ex situ. Furthermore, we reveal that UDCA reduces the expression of ACE2 in the nasal epithelium in humans. Finally, we identify a correlation between UDCA treatment and positive clinical outcomes after SARS-CoV-2 infection using retrospective registry data, and confirm these findings in an independent validation cohort of recipients of liver transplants. In conclusion, we show that FXR has a role in controlling ACE2 expression and provide evidence that modulation of this pathway could be beneficial for reducing SARS-CoV-2 infection, paving the way for future clinical trials