Methylation Analysis of Colitis-Associated Colorectal Carcinomas.

BACKGROUND: Ulcerative colitis is a well-known inflammatory bowel disease. Patients have an increased risk of developing colitis associated carcinoma (CAC). It is important for patient management to be able to distinguish between ulcerative colitis associated carcinoma and sporadic carcinoma (sCRC). However, this distinction is frequently very challenging. It is not readily possible to differentiate this histologically. However, the diagnosis is crucial for the patient's further treatment and follow-up. An attempt was therefore made to develop a diagnostic regime that would enable a reliable distinction between sCRC and CAC. METHODS: We screened 96 patients analyzing more than 850,000 methylation hotspots, to detect distinct epigenetic patterns between both types of carcinomas. Patients with sporadic carcinoma and colitis-associated carcinoma as well as patients with normal colon and patients with confirmed ulcerative colitis without neoplasia were used for the analysis. By extensively filtering the results, methylation sites relevant to distinguish between CAC and sCRC were identified. RESULTS: After the results were filtered, three methylation sites relevant to distinguish between CAC and sCRC were identified. For this purpose, methylation limit values were defined, which favor the samples as CAC or sCRC up to a certain methylation value of the methylation sites. The combination of three methylation sites allows a correct assignment to CAC or sCRC in 94.5% of the cases. CONCLUSION: The results show that these three methylation sites are promising markers in the diagnosis of CAC vs sCRC. Nevertheless, the diagnosis should always be made in conjunction with histomorphological analyses.

Integrin ß6 deficiency protects mice from experimental colitis and colitis-associated carcinoma by altering macrophage polarization.

Background: Given the key role of integrins in maintaining intestinal homeostasis, anti-integrin biologics in inflammatory bowel disease (IBD) are being investigated in full swing. However, the unsatisfactory efficacy and safety of current anti-integrin biologics in clinical trials limit their widespread use in clinic. Therefore, it is particularly important to find a target that is highly and specifically expressed in the intestinal epithelium of patients with IBD. Methods: The function of integrin αvß6 in IBD and colitis-associated carcinoma (CAC) with the underlying mechanisms has been less studied. In the present study, we detected the level of integrin ß6 within inflammation including colitis tissues in human and mouse. To investigate the role of integrin ß6 in IBD and CAC, integrin ß6 deficient mice were hence generated based on the construction of colitis and CAC model. Results: We noted that integrin ß6 was significantly upregulated in inflammatory epithelium of patients with IBD. Integrin ß6 deletion not only reduced infiltration of pro-inflammatory cytokines, but also attenuated disruption of tight junctions between colonic epithelial cells. Meanwhile, lack of integrin ß6 affected macrophage infiltration in mice with colitis. This study further revealed that lack of integrin ß6 could inhibit tumorigenesis and tumor progression in CAC model by influencing macrophage polarization, which was also involved in attenuating the degree of intestinal symptoms and inflammatory responses in mice suffering from colitis. Conclusions: The present research provides a potentially new perspective and option for the treatment of IBD and CAC.

Risk factors for the postoperative recurrence of ulcerative colitis-associated colorectal cancer.

PURPOSE: Although ulcerative colitis-associated colorectal cancer (UC-CRC) has been described, there are few reports regarding recurrent cases of UC-CRC. In this study, we investigated the risk factors for UC-CRC recurrence. METHODS: Recurrence-free survival (RFS) was determined for 144 stage I to III cancer patients among 210 UC-CRC patients from August 2002 to August 2019. The Kaplan‒Meier method was used to obtain the cumulative RFS rate, and the Cox proportional hazard model was used to extract recurrence risk factors. The interaction term between cancer stage and prognostic factors specific to UC-CRC was evaluated using the Cox model. The Kaplan‒Meier method was applied by cancer stage to the UC-CRC-specific prognostic factors for which interaction effects were indicated. RESULTS: There were 18 cases of recurrence involving patients with stage I to III cancer, and the recurrence rate was 12.5%. The cumulative 5-year RFS rate was 87.5%. Multivariable analysis showed that age at surgery (hazard ratio (HR): 0.95, 95% CI: 0.91-0.99, p = 0.02), undifferentiated carcinoma (HR: 4.42, 95% CI: 1.13-17.24, p = 0.03), lymph node metastasis (HR: 4.11, 95% CI: 1.08-15.69, p = 0.03), and vascular invasion (HR: 8.01, 95% CI: 1.54-41.65, p = 0.01) were significant risk factors for recurrence. Patients with stage III CRC in the young adult (age < 50 years) group had a significantly worse prognosis than those in the adult (age ≥ 50 years) group (p < 0.01). CONCLUSION: Age at surgery was identified as a risk factor for UC-CRC recurrence. Young adult patients with stage III cancer may have a poor prognosis.

Advances of Wnt Signalling Pathway in Colorectal Cancer.

Colorectal cancer (CRC) represents one of the most common cancers worldwide, with a high mortality rate despite the decreasing incidence and new diagnostic and therapeutic strategies. CRC arises from both epidemiologic and molecular backgrounds. In addition to hereditary factor and genetic mutations, the strongly varying incidence of CRC is closely linked to chronic inflammatory disorders of the intestine and terrible dietary habits. The Wnt signalling pathway is a complex regulatory network that is implicated in many CRC physiological processes, including cancer occurrence, development, prognosis, invasion, and metastasis. It is currently believed to include classical Wnt/ß-catenin, Wnt/PCP, and Wnt/Ca2+. In this review, we summarise the recent mechanisms and potential regulators of the three branches of the Wnt signalling pathway in CRC.

Epithelial Smad4 Deletion Up-Regulates Inflammation and Promotes Inflammation-Associated Cancer.

Background & Aims: Chronic inflammation is a predisposing condition for colorectal cancer. Many studies to date have focused on proinflammatory signaling pathways in the colon. Understanding the mechanisms that suppress inflammation, particularly in epithelial cells, is critical for developing therapeutic interventions. Here, we explored the roles of transforming growth factor ß (TGFß) family signaling through SMAD4 in colonic epithelial cells. Methods: The Smad4 gene was deleted specifically in adult murine intestinal epithelium. Colitis was induced by 3 rounds of dextran sodium sulfate in drinking water, after which mice were observed for up to 3 months. Nontransformed mouse colonocyte cell lines and colonoid cultures and human colorectal cancer cell lines were analyzed for responses to TGFß1 and bone morphogenetic protein 2. Results: Dextran sodium sulfate treatment was sufficient to drive carcinogenesis in mice lacking colonic Smad4 expression, with resulting tumors bearing striking resemblance to human colitis-associated carcinoma. Loss of SMAD4 protein was observed in 48% of human colitis-associated carcinoma samples as compared with 19% of sporadic colorectal carcinomas. Loss of Smad4 increased the expression of inflammatory mediators within nontransformed mouse colon epithelial cells in vivo. In vitro analysis of mouse and human colonic epithelial cell lines and organoids indicated that much of this regulation was cell autonomous. Furthermore, TGFß signaling inhibited the epithelial inflammatory response to proinflammatory cytokines. Conclusions: TGFß suppresses the expression of proinflammatory genes in the colon epithelium, and loss of its downstream mediator, SMAD4, is sufficient to initiate inflammation-driven colon cancer. Transcript profiling: GSE100082.

Roles for selenium and selenoprotein P in the development, progression, and prevention of intestinal disease.

Selenium (Se) is a micronutrient essential to human health, the function of which is mediated in part by incorporation into a class of proteins known as selenoproteins (SePs). As many SePs serve antioxidant functions, Se has long been postulated to protect against inflammation and cancer development in the gut by attenuating oxidative stress. Indeed, numerous studies over the years have correlated Se levels with incidence and severity of intestinal diseases such as inflammatory bowel disease (IBD) and colorectal cancer (CRC). Similar results have been obtained with the Se transport protein, selenoprotein P (SELENOP), which is decreased in the plasma of both IBD and CRC patients. While animal models further suggest that decreases in Se or SELENOP augment colitis and intestinal tumorigenesis, large-scale clinical trials have yet to show a protective effect in patient populations. In this review, we discuss the function of Se and SELENOP in intestinal diseases and how research into these mechanisms may impact patient treatment.

Transanal total mesorectal excision for restorative coloproctectomy in an obese high-risk patient with colitis-associated carcinoma.

Transanal total mesorectal excision (TaTME) offers great potential for the treatment of malign and benign diseases. However, laparoscopic-assisted TaTME in ulcerative colitis has not been described in more than a handful of patients. We present a 47-year-old highly comorbid female patient with an ulcerative colitis-associated carcinoma of the ascending colon and steroid- refractory pancolitis. A two-stage restorative coloproctectomy including right-sided complete mesocolic excision was conducted. The second step consisted of a successful nerve-sparing TaTME and a handsewn ileal pouch-anal anastomosis. TaTME may extend the possible treatment options in inflammatory bowel disease, especially for high-risk patients.

Increased expression and possible role of chitinase 3-like-1 in a colitis-associated carcinoma model.

AIM: To investigate the possible role of chitinase 3-like-1 (CHI3L1) in the progression of colitis-associated carcinoma (CAC). METHODS: Thirty-four Balb/c mice were randomly assigned to five groups, including the control, CAC control, CAC + caffeine, colitis control and colitis + caffeine. Three animals were sacrificed every two weeks for blinded macroscopic inspection, histological analysis, and total RNA extraction. An immunofluorescent assay was performed using specimens from the colitis control and colitis + caffeine groups to investigate whether the protective effect of caffeine was associated with less oxidative DNA damage. In vitro, HT29 cells pre-stimulated with different concentrations of recombinant CHI3L1 protein and H2O2 were loaded with the DCFH-DA fluorescent probe to determine the effect of CHI3L1 on intracellular reactive oxygen species production. RESULTS: CHI3L1 mRNA was increased during the progression of colon carcinogenesis. Tumors were mostly located in the distal end of the colon where the expression of CHI3L1 was higher than in the proximal colon. Caffeine-treated mice developed fewer tumors and milder inflammation than untreated mice. CHI3L1 protein increased reactive oxygen species in HT29 cells when exposed to H2O2. CONCLUSION: Caffeine reduces tumor incidence by decreasing oxidative DNA damage. CHI3L1 may contribute to CAC by increasing reactive oxygen species production.