Evolutionary history of human colitis-associated colorectal cancer

Objective: IBD confers an increased lifetime risk of developing colorectal cancer (CRC), and colitis-associated CRC (CA-CRC) is molecularly distinct from sporadic CRC (S-CRC). Here we have dissected the evolutionary history of CA-CRC using multiregion sequencing. Design: Exome sequencing was performed on fresh-frozen multiple regions of carcinoma, adjacent non-cancerous mucosa and blood from 12 patients with CA-CRC (n=55 exomes), and key variants were validated with orthogonal methods. Genome-wide copy number profiling was performed using single nucleotide polymorphism arrays and low-pass whole genome sequencing on archival non-dysplastic mucosa (n=9), low-grade dysplasia (LGD; n=30), high-grade dysplasia (HGD; n=13), mixed LGD/HGD (n=7) and CA-CRC (n=19). Phylogenetic trees were reconstructed, and evolutionary analysis used to reveal the temporal sequence of events leading to CA-CRC. Results: 10/12 tumours were microsatellite stable with a median mutation burden of 3.0 single nucleotide alterations (SNA) per Mb, ~20% higher than S-CRC (2.5 SNAs/Mb), and consistent with elevated ageing-associated mutational processes. Non-dysplastic mucosa had considerable mutation burden (median 47 SNAs), including mutations shared with the neighbouring CA-CRC, indicating a precancer mutational field. CA-CRCs were often near triploid (40%) or near tetraploid (20%) and phylogenetic analysis revealed that copy number alterations (CNAs) began to accrue in non-dysplastic bowel, but the LGD/HGD transition often involved a punctuated ‘catastrophic’ CNA increase. Conclusions: Evolutionary genomic analysis revealed precancer clones bearing extensive SNAs and CNAs, with progression to cancer involving a dramatic accrual of CNAs at HGD. Detection of the cancerised field is an encouraging prospect for surveillance, but punctuated evolution may limit the window for early detection

Crocin synergistically enhances the anti-proliferative activity of 5-FU through Wnt/PI3K pathway in a mouse model of colitis-associated colorectal cancer

Colorectal-cancer (CRC) is the third most common cause of cancer-related-death, and hence there is a need for the identification of novel-agents to improve the efficacy of existing-therapies. There is growing evidence for the anti-tumor-activity of crocin, although its activity and molecular-mechanisms in CRC remains to be elucidated. Here we explored the therapeutic-application of crocin or its combination with 5-Flurouracil in a mouse-model of colitis-associated colon-cancer. The anti-proliferative-activity of crocin was assessed in 2- and 3-dimensional cell-culture-models. The migratory-behaviors were determined, while the expression-levels of several-genes were assessed by qRT-PCR/Western-blotting. We examined the anti-inflammatory properties of crocin by pathological-evaluation and disease-activity-index as well as oxidative/ antioxidant markers: malondialdehyde (MDA) and total-thiols (T-SH) levels and superoxide-dismutase (SOD) and catalase (CAT) activity. Crocin suppressed cell-growth and the invasive-behavior of CRC-cells through modulation of the Wnt-pathway and E-cadherin. Moreover, administration of crocin alone, or in combination with 5-FU dramatically reduced the tumor-number and tumor-size in both distal/mid-colon followed by reduction in disease-activity-index. Crocin also suppressed the colonic-inflammation induced by Dextran-sulfate-sodium and notably recovered the increased-levels of MDA, decreased Thiol-levels and activity of CAT-levels. Crocin was able to ameliorate the severe-inflammation with mucosal-ulcers and high grade-dysplastic-crypts as detected by inflammation-score, Crypt-loss, pathological-changes and histology-scores. We demonstrated an antitumor-activity of crocin in CRC and its potential role in improvement of inflammation with mucosal ulcers and high grade dysplastic crypts, supporting the desireability of further investigations on the therapeutic potential of this approach in CRC

Ulcerative Colitis-Associated Colorectal Cancer Prevention by 5-Aminosalicylates: Current Status and Perspectives

International audienc

Consumption of Black Raspberries Altered the Composition of the Fecal Microbiome in Mice Fed a Western Type Diet (OR04-01-19)

Dietary strategies to reduce colonic inflammation and promote gut homeostasis may markedly reduce the risk of colitis-associated colorectal cancer. Previously, we showed that dietary supplementation with black raspberries significantly suppressed colitis and colon tumorigenesis promoted by the consumption a Western type diet in mice. In this study, our goal was to assess the impact of consumption of the TWD with and without black raspberry supplementation on the composition of the fecal microbiome over the course of disease development

Characterization of Chromosomal Instability in Murine Colitis-Associated Colorectal Cancer

Patients suffering from ulcerative colitis (UC) bear an increased risk for colorectal cancer. Due to the sparsity of colitis-associated cancer (CAC) and the long duration between UC initiation and overt carcinoma, elucidating mechanisms of inflammation-associated carcinogenesis in the gut is particularly challenging. Adequate murine models are thus highly desirable. For human CACs a high frequency of chromosomal instability (CIN) reflected by aneuploidy could be shown, exceeding that of sporadic carcinomas. The aim of this study was to analyze mouse models of CAC with regard to CIN. Additionally, protein expression of p53, beta-catenin and Ki67 was measured to further characterize murine tumor development in comparison to UC-associated carcinogenesis in men.The AOM/DSS model (n = 23) and IL-10(-/-) mice (n = 8) were applied to monitor malignancy development via endoscopy and to analyze premalignant and malignant stages of CACs. CIN was assessed using DNA-image cytometry. Protein expression of p53, beta-catenin and Ki67 was evaluated by immunohistochemistry. The degree of inflammation was analyzed by histology and paralleled to local interferon-γ release.CIN was detected in 81.25% of all murine CACs induced by AOM/DSS, while all carcinomas that arose in IL-10(-/-) mice were chromosomally stable. Beta-catenin expression was strongly membranous in IL-10(-/-) mice, while 87.50% of AOM/DSS-induced tumors showed cytoplasmatic and/or nuclear translocation of beta-catenin. p53 expression was high in both models and Ki67 staining revealed higher proliferation of IL-10(-/-)-induced CACs.AOM/DSS-colitis, but not IL-10(-/-) mice, could provide a powerful murine model to mechanistically investigate CIN in colitis-associated carcinogenesis