Sporadic Colorectal Cancer Research Articles

Effect of TLR2 on the proliferation of inflammation-related colorectal cancer and sporadic colorectal cancer

BackgroundColitis-associated cancer (CAC) is a complication of inflammatory bowel disease (IBD) with a poor prognosis because it is often diagnosed in advanced stages with local progression or metastasis. Compared with the more common polyp-induced sporadic colorectal cancer (sCRC), CAC has different molecular mechanisms. Toll-like receptor 2 (TLR2) expression is not limited to cells related to inflammation and immune function. High levels of TLR2 expression in tumor tissues of colorectal cancer (CRC) patients have been reported. This report is to investigate the effects of knockout and knockdown of the TLR2 gene on the proliferation of CAC and sCRC.MethodsTwelve C57BL/6 J wild-type mice (WT) and 12 TLR2 knockout mice (TLR2-/-) were used to rapidly establish a colitis-associated cancer (CAC) model via the 1,2-dimethylhydrazine-dextran sodium sulfate (DMH-DSS) method and were divided into the normal WT control group (NC), TLR2 knockout control group (KC), normal wild-type tumor modeling group (NT), and TLR2 knockout tumor modeling group (KT), with 6 mice in each group. The general performance of the mice during modeling, the gross changes of the colon and the rectum, and the pathological score of HE staining were used to observe tumor growth. The expression of TLR2 was detected by immunohistochemistry, and tumor proliferation was detected by Ki67 labeling. Lentivirus carrying TLR2-RNAi was used to stably infect colorectal cancer cells (HCT116 and HT29) to knock down TLR2 gene expression. The experimental groups included the uninfected control group, negative control group, and gene knockdown group. After infection, the expression of TLR2 protein was detected by Western blot, and cell proliferation and the cell cycle were detected by the CCK-8 method and fluorescence-activated cell sorting. Western blot was used to detect the expression levels of p- NF-κβ, cyclin D1 and cyclin D3 protein in each group of cells.ResultsTLR2 knockout in the CAC model resulted in greater changes in body weight and more severe diarrhea and colorectal hemorrhage. However, knocking out the TLR2 gene reduced the shortening of colorectal length, the number of tumors, and the total tumor volume and inhibited the growth of CAC. Knocking out the TLR2 gene also reduced the pathological score and tumor severity. TLR2 was localized in the cell membrane of the colorectal epithelium of the NC group and of the colorectal tumors of the NT group and was highly expressed in the NT group, while antigen Ki67 was localized in the nucleus of the colorectal tumor cells of the NT group and the KT group, and its expression was reduced in the KT group. In an in vitro sporadic colorectal cancer cell experiment, TLR2 protein in the TLR2 knockdown group was significantly downregulated, and TLR2 knockdown significantly inhibited the proliferation of HCT116 and HT29 colorectal cancer cells, resulting in G1 phase arrest. The expression levels of p-NF-κβ, cyclin D1 and cyclin D3 proteins in TLR2 gene knockdown group cells were significantly reduced.ConclusionKnockout and knockdown of TLR2 can inhibit the proliferation of inflammation-related colorectal cancer and sporadic colorectal cancer.

Soy Metabolism by Gut Microbiota from Patients with Precancerous Intestinal Lesions.

Background: Colorectal cancer (CRC) requires the presence of a variety of factors predisposing a tumorigenic milieu. Excluding familial clustering and hereditary CRC syndromes, the development of sporadic CRC from precancerous lesions is influenced by tissue inflammation, modulation of intestinal immunity, hormones, dietary habits and gut microbiota composition. As concerning the last two aspects, the intestinal presence of equol, the most biologically active metabolite of the soy isoflavone daidzein and the presence of a genetic determinant of gut microbiota able to metabolize daidzein, seem to lower the CRC risk. It has been hypothesized that the anaerobic microorganisms of the Bacteroides genus play a role in equol production. Aim: To evaluate the presence of (i) anaerobic gut microbiota and (ii) the urinary levels of soy isoflavones (daidzein, genistein and equol) in patients with and without precancerous lesions, challenged with a daidzein-rich soy extract. Methods: Consecutive subjects undergoing colonoscopy participated to the study. Feces were collected from all patients one week before colonoscopy for gut microbiota studies. After the endoscopy examination and the histological evaluation, 40 subjects, 20 with sporadic colorectal adenomas (SCA/P group) and 20 without proliferative lesions (control group) were enrolled for the study. Urine levels of soy isoflavones daidzein, genistein and their metabolite equol, were determined by high performance liquid chromatographic (HPLC) analysis and gut microbiota analysis was performed by Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) procedure. Results: Seventeen different bacterial species were identified in the fecal samples of the forty subjects participating to the study. Ten bacterial species resulted anaerobic Gram-negative bacteria, all belonging to the Bacteroides genus. A significant difference of bacteria species was evidenced in the fecal samples of the two groups of subjects. Particularly important was the evidence of Parabacteroides distasonis, Clostridium clostridioforme and Pediococcus pentasaceus only in control fecal samples, such as the presence of Bacteroides fragilis and Prevotella melaningenica only in SCA/P fecal samples. Concerning the soy isoflavones levels, no statistically significant differences were revealed in the genistein and daidzein urinary levels between the two groups of subjects. On the contrary, urinary equol levels were undetectable in ten SCA/P subjects and in two controls; moreover, when present, the levels of urinary equol were significantly lower in SCA/P subjects compared to controls (0.24 ± 0.27 mg/24 hrs vs. 21.25 ± 4.3 mg/24 hrs, respectively, p = 1.12 × 10−6). Conclusions: Our results suggest that the presence of anaerobic Bacteroides in the colon, and the production of equol from soy, could determine a milieu able to contrast the development of colonic mucosa proliferative lesions.

Prognostic implications of EGFR protein expression in sporadic colorectal tumors: Correlation with copy number status, mRNA levels and miRNA regulation

Sporadic colorectal cancer (sCRC) is the third most frequent cancer worldwide and the second most common cause of cancer-related deaths (mainly due metastatic dissemination). We investigated the immunohistochemical expression of frequently altered proteins in primary tumors from 51 patients (25 liver metastatic and 26 non-metastatic cases) with a median 103 months follow-up (103 months). We evaluated EGFR copy number (using SNP arrays and FISH) and its expression and regulation (by mRNA and miRNA arrays). We found differences between metastatic and non-metastatic sCRCs for MLH1 (p = 0.05), PMS2 (p = 0.02), CEA (p < 0.001) and EGFR (p < 0.001) expression. EGFR expression was associated with lymph node metastases (p = 0.001), liver metastases at diagnosis (p < 0.001), and advanced stage (p < 0.001). There were associations between EGFR expression-, EGFR gene copy number- and EGFR mRNA levels. We found potential interactions of two miRNAs targeting EGFR expression, (miR-134 and miR-4328, in non-metastatic and metastatic tumors, respectively). EGFR expression was associated with a worse outcome (p = 0.005). Multivariate analysis of prognostic factors for overall survival identified that, the expression of EGFR expression (p = 0.047) and pTNM stage (p < 0.001) predicted an adverse outcome. EGFR expression could be regulated by amplification or polysomies (in metastatic tumors), or miRNAs (miRNA-134, in non-metastatic tumors). EGFR expression in sCRC appears to be related to metastases and poor outcome.

A31 ALTERED SMALL INTESTINAL EPITHELIAL HOMEOSTASIS AND CELL FATE DECISION UPON LOSS OF TRP53 IN KRT15+ INTESTINAL STEM CELLS

Abstract Background Intestinal homeostasis is mainly maintained by two groups of stem cells: Lgr5+ stem cells and reserve stem cells. Recently, we reported that Krt15+ cells are present in small intestinal and colon epithelia, and harbor self-renewal, multipotent and regenerative capacities. Initiation of sporadic colorectal cancer has been described in Krt15+ stem cells, Lgr5+ stem cells and reserve stem cells following the loss of Apc. While these intestinal stem cell (ISC) populations can act as tumor-initiating cells in sporadic colon cancer, little is known about the cell-of-origin of colitis-associated colon cancer. TP53 alteration is reported as an early event in colitis-associated colon cancer cases. Therefore, we hypothesize that Trp53 loss specifically in Krt15+ stem cells will perturb the epithelial homeostasis and lead to tumor formation Aims Identify if Krt15+ cells may act as the cell-of-origin in colitis-associated colorectal cancer. Methods To induce Trp53 loss specifically in Krt15+ cells, we generated Krt15-CrePR1;Trp53fl/fl (Krt15△Trp53) mice, induced Cre recombination by injecting RU486 (PR agonist) and euthanized the mice after 12 months following recombination. Histological analysis was performed on small intestinal tissues. Results Results: Trp53 loss in Krt15+ cells severely perturbed small intestinal morphology. Increased crypt (proliferative compartment) length correlated with no proliferation changes surprisingly but higher number of Paneth cells and abnormal presence of goblet cells. Interestingly, we also observed the presence of cells expressing both Paneth and goblet cells markers suggesting a deregulation of secretory cell fate decision. Decreased expression of Hes1 and increased β-catenin nuclear expression in the small intestinal crypt of Krt15△Trp53 mice suggest altered Notch and Wnt signaling. Furthermore, villi (differentiated compartment) were significantly wider and shorter, and showed accumulation of activated fibroblasts. Finally, we observed inflammatory lesions as well as adenomas in the small intestine of Krt15△Trp53 mice which remain to be further characterized Conclusions Conclusion: In summary, Trp53 loss specifically in Krt15+ cells impaired cell fate decision, induced inflammation and initiated tumor formation. Overall, these results suggest that Krt15+ cells could act as the cell-of-origin of colitis-associated colon cancer. Funding Agencies Cancer Research Society, CRC Tier 2

A41 LOSS OF SATB2 EXPRESSION IN COLORECTAL CANCER IS ASSOCIATED WITH DURATION OF INFLAMMATORY BOWEL DISEASE

Abstract Background Patients with inflammatory bowel disease (IBD) are at higher risk for developing colitis-associated colorectal cancer (CAC). Clinical and endoscopic features are used to stratify the risk of CAC, but new biomarkers are necessary to improve this stratification. Recent studies have shown that loss of expression of special AT-rich sequence binding protein 2 (SATB2) is frequent in CAC compared to sporadic colorectal cancer and this SATB2 status is found in pre-cancerous dysplastic lesions as well. However, the relationship of known clinical risk factors for CAC and loss of SATB2 has not been explored. Aims To assess the association of loss of SATB2 expression in CAC with clinical characteristics of IBD. Methods Patients with a known diagnosis of ileocolonic or colonic Crohn’s disease (CD), ulcerative colitis (UC), or IBD unclassified (IBDU) who underwent colectomy between October 2010 and December 2017 for CAC were included. SATB2 expression in neoplastic tissue was evaluated using immunohistochemistry (IHC), where less than 5% of tumor cells showing staining was considered loss of SATB2. Tumor grade, P53 and mismatch repair (MMR) status were assessed as well. Available clinical data such as sex, smoking status, IBD diagnosis (CD, UC or IBDU), age at IBD diagnosis, duration of IBD, extent of colitis and previous medications were collected. We used a generalized linear model to assess the association between these biomarkers and clinical data. Results A total of 58 patients with mean age at CAC diagnosis of 50.3 ±13 years, 27 (46%) females were analyzed. Mean IBD duration was 17.6 ±10 years and 22 (37.9%), 34 (58.6%) and 2 (3.4%) were CD, UC and IBDU, respectively. Thirty-two (55.2%) CACs had loss of SATB2 expression. There was no association between age at CAC diagnosis or grade of the tumor and loss of SATB2. However, longer duration of IBD (21.2 ± 9 years vs 13.7 ± 9 years, p = 0.01) was significantly associated with loss of SATB2. There was no association between SATB2 status and other explored clinical or endoscopic variables. Tumors with P53 mutation were associated with a younger age at diagnosis of CAC (47.2 ±13 vs 55.0 ±12 years, p = 0.03), but no other associations of this marker or MMR with clinical or endoscopic variables of IBD were found. Conclusions Loss of SATB2 expression is significantly associated with IBD duration, a well-known risk factor for CAC. This association with duration of IBD could denote an effect of longer chronic inflammation on SATB2 status. Given the previously reported association of loss of expression of SATB2 with pre-cancerous lesions in IBD patients, this could be a potential biomarker for risk of CAC. Funding Agencies National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Biomarkers for Early Detection of Colitis-associated Colorectal Cancer - Current Concepts, Future Trends.

Colitis-associated colorectal cancer (CAC) remains a critical complication of ulcerative colitis (UC) with a mortality of approximately 15%, which makes early CAC diagnosis crucial. The current standard of surveillance, with repetitive colonoscopies and histological testing of biopsied mucosa samples, is burdensome and expensive, and therefore less invasive methods and reliable biomarkers are needed. Significant progress has been made, thanks to continuous extensive research in this field, however, no clinically relevant biomarker has been established so far. This review of the current literature presents the genetic and molecular differences between CAC and sporadic colorectal cancer and covers progress made in the early detection of CAC carcinogenesis. It focuses on biomarkers under development, which can easily be tested in samples of body fluids or breath and, once made clinically available, will help to differentiate between progressors (UC patients who will develop dysplasia) from non-progressors and enable early intervention to decrease the risk of cancer development.

Autocatalytic Tissue Polymerization Reaction Mechanism in Colorectal Cancer Development and Growth.

The goal of our study was to measure the kinetics of human colorectal cancer (CRC) development in order to identify aberrant mechanisms in tissue dynamics and processes that contribute to colon tumorigenesis. The kinetics of tumor development were investigated using age-at-tumor diagnosis (adenomas and CRCs) of familial adenomatous coli (FAP) patients and sporadic CRC patients. Plots of age-at-tumor diagnosis data as a function of age showed a distinct sigmoidal-shaped curve that is characteristic of an autocatalytic reaction. Consequently, we performed logistics function analysis and found an excellent fit (p < 0.05) of the logistic equation to the curves for age-at-tumor diagnoses. These findings indicate that the tissue mechanism that becomes altered in CRC development and growth involves an autocatalytic reaction. We conjecture that colonic epithelium normally functions as a polymer of cells which dynamically maintains itself in a steady state through an autocatalytic polymerization mechanism. Further, in FAP and sporadic CRC patients, mutation in the adenomatous polyposis coli (APC) gene increases autocatalytic tissue polymerization and induces tumor tissues to autocatalyze their own progressive growth, which drives tumor development in the colon.

Systemic Chemotherapy for Metastatic Colitis-Associated Cancer Has a Worse Outcome Than Sporadic Colorectal Cancer: Matched Case Cohort Analysis

BackgroundColitis-associated cancers (CAC) are a catastrophic complication of inflammatory bowel disease; at diagnosis, CAC is frequently at an advanced stage. Although the genomic alterations (GA) in CAC are different from sporadic colorectal cancer (CRC), the same systemic therapies are used. We compared clinically relevant outcomes using standard care systemic chemotherapy of stage IV CAC versus a matched patient control cohort of stage IV CRC patients. Patients and MethodsA retrospective matched cohort design was used. Eighteen cases of stage IV CAC (7 ulcerative colitis, 11 Crohn disease) and 18 CRC were identified. GA analysis was available for all patients. Outcome endpoints included response rate and response duration, progression-free survival, and OS. ResultsAlthough the response rates were similar (CAC 35.7% vs. CRC 57.1%, P = .45), the median duration of response for CAC was significantly shorter (1.4 months, vs. CRC 11.8 months, P = .006). There was no difference in dose density of first-line therapy between cohorts, suggesting that shorter response duration was due to more rapid development of chemotherapy resistance. Median OS was significantly shorter for CAC patients (13 vs. 27.6 months, P = .034). As expected, there was a difference in the spectrum of GA between CAC and CRC cohorts. However, GA associated with poor prognosis (eg, B-Raf) were no more frequent in the CAC cohort. ConclusionClinically meaningful outcomes of duration of response and OS are worse for CAC versus sporadic CRC patients treated with FOLFOX or FOLFIRI as first therapy for metastatic disease.

Significance of the gut microbiome in multistep colorectal carcinogenesis.

Colorectal cancer (CRC) is highly prevalent worldwide. In 2018, there were over 1.8 million new cases. Most sporadic CRC develop from polypoid adenomas and are preceded by intramucosal carcinoma (stage 0), which can progress into more malignant forms. This developmental process is known as the adenoma‐carcinoma sequence. Early detection and endoscopic removal are crucial for CRC management. Accumulating evidence suggests that the gut microbiota is associated with CRC development in humans. Comprehensive characterization of this microbiota is of great importance to assess its potential as a diagnostic marker in the very early stages of CRC. In this review, we summarized recent studies on CRC‐associated bacteria and their carcinogenic mechanisms in animal models, human cell lines and human cohorts. High‐throughput technologies have facilitated the identification of CRC‐associated bacteria in human samples. We have presented our metagenome and metabolome studies on fecal samples collected from a large Japanese cohort that revealed stage‐specific phenotypes of the microbiota in CRC. Furthermore, we have discussed the potential carcinogenic mechanisms of the gut microbiota, from which we can infer whether changes in the gut microbiota are a cause or effect in the multi‐step process of CRC carcinogenesis.

Genomic alterations in colitis-associated cancers in comparison to those found in sporadic colorectal cancer and present in precancerous dysplasia.

191 Background: Patients with inflammatory bowel disease (IBD) [Crohn’s disease (CD) and ulcerative colitis (UC)] are at increased risk for small bowel or colorectal cancers (Colitis Associated Cancers, CAC). Currently CAC is treated the same as sporadic colorectal cancer (CRC) with significantly shorter overall survival for advanced CAC compared to matched patients with CRC. In a pilot series, we found that tumors developing in IBD have distinct genomic alterations (GA) with potential implications for early detection and treatment. We now extend this analysis and characterize the relationship of GA in synchronous dysplasia and cancer. Methods: 104 CAC (54 UC-associated and 50 CD-associated) were sequenced with targeted-exome sequencing of &gt; 300 cancer-related genes. GA in CAC were compared to those reported for sporadic CRC. Whole exome sequencing was performed on paired mucosa, dysplasia and carcinoma samples obtained from 15 colectomy specimens; in these cases, expert pathology review confirmed normal appearing mucosa intervening between areas of dysplasia and CAC. Results: TP53 mutations (89%), MYC amplifications (24%), and cell cycle copy number alterations (20%) were significantly enriched in CAC compared to sporadic CRC, while APC alterations (21%) were significantly less common in CAC compared to sporadic CRC. Distinct GA in CAC consisted of IDH1 R132 mutations (7%) and FGFR pathway alterations (7%). While IDH1 R132 mutations and PI3K pathway alterations were more common in CD-associated CAC, MAPK ( BRAF/ MEK1) alterations were more common in UC-associated CAC. GA in CACs did not significantly vary by duration of preceding IBD. GA were often shared in dysplasia and carcinoma, despite normal-appearing intervening mucosa. GA involving TP53, APC, KRAS, and IDH1 mutations were identified in dysplasia and shared between CAC and dysplasia. Conclusions: CAC exhibit distinct GA compared to sporadic CRC with near universal TP53 mutation, increased copy number alterations involving transcription factors and cell cycle genes, and unique drivers. A field effect can be seen for GA between distant dysplasia and carcinoma, but many GA remain private to CAC.

Metachronous colorectal pathology among survivors of young-onset colorectal cancer: Implications for postresection colonoscopic surveillance.

64 Background: Patients with sporadic young-onset colorectal cancer (CRC) are postulated to have a more biologically active colorectum prone to malignant transformation earlier in life. It is unknown whether there is elevated risk for metachronous colorectal pathology after the index cancer. We aimed to define this risk, to inform their post-resection endoscopic surveillance. Methods: Consecutive CRC patients (aged 18-50, n = 728) were prospectively followed after surgical resection between 2009 and 2017. Patients presenting with hereditary CRC, recurrent disease, or without endoscopy follow-up were excluded. All endoscopy records were subjected to natural language processing and further reviewed. Metachronous colorectal pathology of interest included: high-risk adenoma (≥1cm in size, &gt; 3 in number, or tubulovillious/high-grade dysplasia histology), second CRC, and endoscopically detectable local recurrence. Results: During a 48-month (median) follow-up, 457 patients underwent 1,192 person-years of colonoscopic follow-up. The median age at CRC diagnosis was 44 years. Disease arose from the proximal colon in 9.4%, distal colon in 23.0% and rectum in 67.6%, and was stages I/II in 191 (41.8%), III in 185 (40.4%), and IV in 81 (17.7%). The majority (95.8%) underwent segmental resection, while the remainder had extended resections for synchronous pathology not amendable to preoperative endoscopic clearance. The overall incidence of metachronous pathology was 32 per 1000 person-years: 31 patients developed high-risk adenomas (6.8%), 1 had a second CRC (0.2%), and 7 had luminal recurrences (1.5%). The median time to metachronous pathology was 13.9 (IQR: 11.8-33.1) months, with 21 (53.8%) detected between 12 and 48 months post-resection. Conclusions: For young-onset CRC survivors, the incidence of metachronous colorectal pathology was 32 per 1000 person-years of follow-up. Given the time pattern of detection, adding an interval colonoscopy between the current recommended post-resection surveillance at 12 and 48 months may be beneficial. [Table: see text]

A prospective cohort analysis of gut microbial co-metabolism in Alaska Native and rural African people at high and low risk of colorectal cancer

Alaska Native (AN) people have the world's highest recorded incidence of sporadic colorectal cancer (CRC) (∼91:100,000), whereas rural African (RA) people have the lowest risk (<5:100,000). Previous data supported the hypothesis that diet affected CRC risk through its effects on the colonic microbiota that produce tumor-suppressive or -promoting metabolites. We investigated whether differences in these metabolites may contribute to the high risk of CRC in AN people. A cross-sectional observational study assessed dietary intake from 32 AN and 21 RA healthy middle-aged volunteers before screening colonoscopy. Analysis of fecal microbiota composition by 16S ribosomal RNA gene sequencing and fecal/urinary metabolites by 1H-NMR spectroscopy was complemented with targeted quantification of fecal SCFAs, bile acids, and functional microbial genes. Adenomatous polyps were detected in 16 of 32 AN participants, but not found in RA participants. The AN diet contained higher proportions of fat and animal protein and less fiber. AN fecal microbiota showed a compositional predominance of Blautia and Lachnoclostridium, higher microbial capacity for bile acid conversion, and low abundance of some species involved in saccharolytic fermentation (e.g., Prevotellaceae, Ruminococcaceae), but no significant lack of butyrogenic bacteria. Significantly lower concentrations of tumor-suppressive butyrate (22.5±3.1 compared with 47.2±7.3 SEM µmol/g) coincided with significantly higher concentrations of tumor-promoting deoxycholic acid (26.7±4.2 compared with 11±1.9 µmol/g) in AN fecal samples. AN participants had lower quantities of fecal/urinary metabolites than RA participants and metabolite profiles correlated with the abundance of distinct microbial genera in feces. The main microbial and metabolic CRC-associated markers were not significantly altered in AN participants with adenomatous polyps. The low-fiber, high-fat diet of AN people and exposure to carcinogens derived from diet or environment are associated with a tumor-promoting colonic milieu as reflected by the high rates of adenomatous polyps in AN participants.

DOP37 Neoplastic lesions outside diseased area in inflammatory bowel disease patients: A national cohort study

Abstract Background Patients with inflammatory bowel diseases (IBD) are at increased risk of dysplasia and colitis-associated cancer (CAC). The presentation of (pre)neoplastic lesions (low-grade dysplasia (LGD), high-grade dysplasia (HGD) or colorectal cancer (CRC) is reported to vary depending if the lesions are located inside disease area (IDA) or outside diseased area (ODA). The primary aim was to analyse the characteristics and prognostic of IDA compared with ODA neoplastic lesions in a large cohort of IBD patients. Methods We performed a multicentre retrospective pathological data collection from 7 tertiary referral regional or academic IBD centres in Belgium. Clinical, endoscopic and pathological data were retrieved through retrospective electronic chart review. From the IBD pathology databases, 1183 colorectal lesions were identified in 541 IBD patients: 415 developed dysplasia (77%) and 126 CRC (23%) during their follow-up. Biopsies and surgical specimen were centrally reviewed by an expert IBD pathologist to confirm the diagnosis of dysplasia and/or CRC. Results Demographic and clinical variables of the study population are summarised in Table 1. More patients with IDA lesions had HGD (9%) or CAC (27%) during their follow-up compared with the group of patients with ODA lesions (3% of HGD and 11% of CRC) (p &amp;lt; 0,0001). Mortality was higher in patients with IDA than in those with ODA lesions (p &amp;lt; 0.05). When comparing IBD patients with IDA lesions and CAC (=111) to those with ODA lesions and sporadic CRC (n = 15), median age at IBD diagnosis was lower (29 (IQR:22–49) vs. 41(IQR:28–54) years; p = 0.0001). Characteristics of the 1183 neoplastic lesions are summarised in Table 2. IDA lesions were more frequently non-visible, non-polypoid and ≥ 1 cm than ODA lesions (p &amp;lt; 0.0001). ODA sporadic CRC was more frequently located in the right colon compared with IDA CAC (5/16 (31%) vs. 21/133 (16%), p &amp;lt; 0.01). Conclusion Neoplastic lesions outside the diseased area were more likely to be visible, polypoid, &amp;lt; 1cm, in the right colon and diagnosed at endoscopy than inside disease area lesions. A lower prevalence of HGD and Cancer were reported with neoplastic lesions outside the diseased area.

Autophagy of Intestinal Epithelial Cells Inhibits Colorectal Carcinogenesis Induced by Colibactin-Producing Escherichia coli in ApcMin/+ Mice

Colibactin-producing Escherichia coli (CoPEC) colonize the colonic mucosa of a higher proportion of patients with vs without colorectal cancer (CRC) and promote colorectal carcinogenesis in susceptible mouse models of CRC. Autophagy degrades cytoplasmic contents, including intracellular pathogens, via lysosomes and regulates intestinal homeostasis. We investigated whether inhibiting autophagy affects colorectal carcinogenesis in susceptible mice infected with CoPEC. Human intestinal epithelial cells (IECs) (HCT-116) were infected with a strain of CoPEC (11G5 strain) isolated from a patient or a mutant strain that does not produce colibactin (11G5ΔclbQ). Levels of ATG5, ATG16L1, and SQSTM1 (also called p62) were knocked down in HCT-116 cells using small interfering RNAs. ApcMin/+ mice and ApcMin/+ mice with IEC-specific disruption of Atg16l1 (ApcMin/+/Atg16l1ΔIEC) were infected with 11G5 or 11G5ΔclbQ. Colonic tissues were collected from mice and analyzed for tumor size and number and by immunohistochemical staining, immunoblot, and quantitative reverse transcription polymerase chain reaction for markers of autophagy, DNA damage, cell proliferation, and inflammation. We analyzed levels of messenger RNAs (mRNAs) encoding proteins involved in autophagy in colonic mucosal tissues from patients with sporadic CRC colonized with vs without CoPEC by quantitative reverse-transcription polymerase chain reaction. Patient colonic mucosa with CoPEC colonization had higher levels of mRNAs encoding proteins involved in autophagy than colonic mucosa without these bacteria. Infection of cultured IECs with 11G5 induced autophagy and DNA damage repair, whereas infection with 11G5ΔclbQ did not. Knockdown of ATG5 in HCT-116 cells increased numbers of intracellular 11G5, secretion of interleukin (IL) 6 and IL8, and markers of DNA double-strand breaks but reduced markers of DNA repair, indicating that autophagy is required for bacteria-induced DNA damage repair. Knockdown of ATG5 in HCT-116 cells increased 11G5-induced senescence, promoting proliferation of uninfected cells. Under uninfected condition, ApcMin/+/Atg16l1ΔIEC mice developed fewer and smaller colon tumors than ApcMin/+ mice. However, after infection with 11G5, ApcMin/+/Atg16l1ΔIEC mice developed more and larger tumors, with a significant increase in mean histologic score, than infected ApcMin/+ mice. Increased levels of Il6, Tnf, and Cxcl1 mRNAs, decreased level of Il10 mRNA, and increased markers of DNA double-strand breaks and proliferation were observed in the colonic mucosa of 11G5-infected ApcMin/+/Atg16l1ΔIEC mice vs 11G5-infected ApcMin/+ mice. Infection of IECs and susceptible mice with CoPEC promotes autophagy, which is required to prevent colorectal tumorigenesis. Loss of ATG16L1 from IECs increases markers of inflammation, DNA damage, and cell proliferation and increases colorectal tumorigenesis in 11G5-infected ApcMin/+ mice. These findings indicate the importance of autophagy in response to CoPEC infection, and strategies to induce autophagy might be developed for patients with CRC and CoPEC colonization.

Effects of high-fat diet and intestinal aryl hydrocarbon receptor deletion on colon carcinogenesis.

Consumption of a high-fat diet has been associated with an increased risk of developing colorectal cancer (CRC). However, the effects of the interaction between dietary fat content and the aryl hydrocarbon receptor (AhR) on colorectal carcinogenesis remain unclear. Mainly known for its role in xenobiotic metabolism, AhR has been identified as an important regulator for maintaining intestinal epithelial homeostasis. Although previous research using whole body AhR knockout mice has revealed an increased incidence of colon and cecal tumors, the unique role of AhR activity in intestinal epithelial cells (IECs) and modifying effects of fat content in the diet at different stages of sporadic CRC development are yet to be elucidated. In the present study, we have examined the effects of a high-fat diet on IEC-specific AhR knockout mice in a model of sporadic CRC. Although loss of AhR activity in IECs significantly induced the development of premalignant lesions, in a separate experiment, no significant changes in colon mass incidence were observed. Moreover, consumption of a high-fat diet promoted cell proliferation in crypts at the premalignant colon cancer lesion stage and colon mass multiplicity as well as β-catenin expression and nuclear localization in actively proliferating cells in colon masses. Our data demonstrate the modifying effects of high-fat diet and AhR deletion in IECs on tumor initiation and progression.NEW & NOTEWORTHY Through the use of an intestinal-specific aryl hydrocarbon receptor (AhR) knockout mouse model, this study demonstrates that the expression of AhR in intestinal epithelial cells is required to reduce the formation of premalignant colon cancer lesions. Furthermore, consumption of a high-fat diet and the loss of AhR in intestinal epithelial cells influences the development of colorectal cancer at various stages.

Supplementation with phytoestrogens and insoluble fibers reduces intestinal carcinogenesis and restores ER-β expression in Apc-driven colorectal carcinogenesis.

Supplementation with phytoestrogens and insoluble fibers has been reported to reduce duodenal polyps in colectomized familial adenomatous polyposis patients, with a mechanism involving, at least in part, upregulation of estrogen receptor-β subtype, whose expression is lowered during intestinal tumorigenesis. These data suggest a protective effect also in the colon, the main target organ for tumorigenesis in familial adenomatous polyposis and a major cancer type in non-familial (sporadic) cancers. Therefore, we tested whether a similar preparation might reduce tumorigenesis in the colon of Pirc rats (F344/NTac-Apc) mutated in the Apc gene and thus, like familial adenomatous polyposis patients, spontaneously developing multiple tumors in the colon. We first demonstrate that estrogen receptor-β expression in Pirc rat colon is significantly down-regulated compared to age-matched wt rats. Then, Pirc rats aged 1 month were treated for 3 months with Adipol (Adi), a patented preparation containing phytoestrogens and insoluble fibers. Colon tumorigenesis was significantly reduced by Adi treatment (colon tumors/rat were 5.3 ± 0.8 and 2.9 ± 0.3, Mucin Depleted Foci/rat 127 ± 6.6 and 97.1 ± 8.6 in Controls and Adi-treated rats, respectively, means ± SE, P < 0.01). The treatment also normalized colon proliferation pattern along the crypt and significantly increased apoptosis in colon tumors. Estrogen receptor-β expression was increased by Adi treatment, especially in the tumors. These positive effects suggest that Adipol may be exploited as a chemopreventive agent to reduce cancer risk in familial adenomatous polyposis patients and to postpone prophylactic colectomy. Moreover, given the similarities between familial adenomatous polyposis and sporadic colorectal cancer, it might also be used as chemopreventive agent in colorectal cancer patients at risk.

The correlation between DNA mismatch repair status and the clinicopathological and molecular features of Chinese sporadic colorectal cancer

BackgroundDNA mismatch repair (MMR) genes play an important role in cancer development. Deficiencies in these genes may cause microsatellite instability (MSI), which can cause colorectal cancer (CRC). Therefore, we evaluate the relationship between MMR status and the clinicopathological and molecular features of Chinese patients with sporadic CRC.MethodsWe evaluated 1,405 patients who had undergone primary tumour resection, and divided them into MMR deficiency (dMMR) and MMR proficiency (pMMR) groups, according to their MMR gene expressions. All clinicopathological and molecular features were obtained from pathology reports.ResultsThe dMMR group contained 125 patients and the pMMR group contained 1 280 patients. Patients with dMMR were more likely to be younger (P<0.05), have poorly differentiated tumours (14.6%), tumours with negative peripheral nerve invasiveness (10.2%), and right-side tumours. Multivariate analysis revealed that the significant independent risk factors for dMMR-related CRC were younger age (OR: 0.979, 95% CI: 0.960–0.998), larger tumour diameter (OR: 1.313, 95% CI: 1.162–1.484), poor differentiation, no peripheral nerve invasiveness (OR: 3.018, 95% CI: 1.258–7.239), right-side colon cancer (OR: 10.821, 95% CI: 4.895–23.922), Bcl-2 positivity (OR: 0.209, 95% CI: 0.095–0.458), topoisomerase II negativity (OR: 3.333, 95% CI: 1.563–7.103) and glutathione S-transferase (GST) negativity (OR: 1.748, 95% CI: 1.009–3.027).ConclusionsYounger age, poorly differentiated tumours, negative peripheral nerve invasiveness, right-side tumours, Bcl-2 positivity, topoisomerase II negativity and GST negativity increased the likelihood of dMMR in Chinese patients with sporadic CRC.

Clinicopathological and molecular features of sporadic colorectal cancers with DNA mismatch repair deficiency: A single center experience

DNA mismatch repair (MMR) proteins may play an important role in colorectal carcinogenesis. In our study, the clinicopathological features of defective MMR in sporadic colorectal adenocarcinomas (CRCs) cases were examined. This is a retrospective study, 457 consecutive cases of colorectal carcinoma with immunohistochemical (IHC) studies for DNA MMR were included.The immunohistochemically (IHC) MMR results of 457 cases were; nuclear expression was intact (proficient, pMMR) in 401 (87.7%) cases and loss of nuclear expression (deficient, dMMR) was found in 56 cases (12.3%). High probability of Lynch syndrome ratio was 2.4% (11/457) in all cases. The loss of PMS2 was predominantly detected in dMMRcases (78.6%). Seventy eight percent of dMMR tumors were located in the proximal colon. In dMMR tumors, prominent peritumoral lymphoid aggregates (LAs) (85.7%) and tumor-infiltrating lymphocytes (TILs) (78.6%) were observed. Among 56 colorectal cancers, we observed expanding /pushing growth pattern in 41 tumors (73.2%), and infiltrative growth pattern in 15 cancers (16.8%). Medullary, mucinous and signet ring cell carcinomas were observed in approximately half of the cases, but there was no statistically significant relationship. Eighty nine percent of dMMR cases had advanced pathologic tumor stage (pT3 or pT4), and this rate was 82.5% in pMMR cases. The average number of positive lymph nodes in cases with dMMR was higher than in pMMR. KRAS mutations were detected in 7.2% (4/13) patients and 14.3% (8/13) patients with MLH1 promoter methylation was observed. Seventy percent of patients with dMMR were alive (n=44) and the mean age of the patients who died was higher. A statistically significant relationship was found between the patients who died and the mean age of surviving patients (p = 0.036). We conclude that the dMMR patients constitutes have a number of distinctive clinicopathological features subtype of sporadic CRC. The overall frequency of defective MMR in colorectal carcinoma cases was found to be Turkish population similar to western studies. dMMR in CRCs were more likely to be of advanced pathologic tumor stage to have a mucinous tumor component and positive LN to show PMS2 loss and to harbour higher numbers of both peritumoral LAs and TILs. They were also more likely to be proximal colon and to occur in male.

Prognostic value of a combination of innovative factors (gut microbiota, sarcopenia, obesity, metabolic syndrome) to predict surgical/oncologic outcomes following surgery for sporadic colorectal cancer: a prospective cohort study protocol (METABIOTE)

IntroductionColorectal cancer (CRC) is still associated with poor prognosis, especially in patients with advanced disease. Development of new prognostic tools replacing or supplementing those routinely used is definitely needed, with...

Hypothesis: Retinoblastoma protein inactivation mediates effects of histone deacetylase inhibitor-induced Wnt hyperactivation in colorectal cancer cells.

Butyrate, a product of dietary fiber and a histone deacetylase inhibitor, induces apoptosis of colorectal cancer cells; this effect of butyrate is in part mediated by its ability to hyperactivate Wnt signaling, and may in part explain the preventive action of dietary fiber against colorectal cancer. However, the mechanisms by which Wnt hyperactivation promotes apoptosis are unknown. Inactivation of the retinoblastoma tumor suppressor occurs in some cancers and can lead to context-dependent cell proliferation or cell death/apoptosis. The function of retinoblastoma protein (Rb) in normal cells is modulation of cell cycle; inactivation of Rb allows for cell cycle progression and, hence, cell proliferation. Wnt signaling is upregulated in a variety of cancers, and deregulated Wnt signaling is a key initiating event in most cases of sporadic colorectal cancer. It has been shown that Wnt signaling activated by APC inactivation can synergize with the inactivation of Rb to induce apoptosis in a manner mediated by increased TORC1 activity, leading to induced metabolic and energy stress. Rb is typically not inactivated in colorectal cancer; however, Rb is phosphorylated and deactivated during cell cycle G1/S transition. This manuscript posits that it is during this time that butyrate/histone deacetylase inhibitor-induced Wnt hyperactivation induces apoptosis in colorectal cancer cells. Thus, the inactivation of Rb in cell cycle progression may synergize with Wnt hyperactivation to induce apoptosis in response to histone deacetylase inhibitors. The hypothesis is that hyperactivation of Wnt signaling enhances colorectal cancer cell apoptosis via the interaction between upregulated Wnt signaling and inactivated Rb during cell cycle progression. This paper discusses this hypothesis and offers initial experimental approaches for testing the hypothesis. A better understanding of how histone deacetylase inhibitors induce colorectal cancer cell apoptosis through hyperactivation of Wnt signaling, and of cross-talk between repression of cell cycle and induction of apoptosis that occurs with treatment with histone deacetylase inhibitors, can assist in the development of novel therapies for colorectal cancer.