Mucosal metabolites fuel the growth and virulence of E. coli linked to Crohn's disease

Elucidating how resident enteric bacteria interact with their hosts to promote health or inflammation is of central importance to diarrheal and inflammatory bowel diseases across species. Here, we integrated the microbial and chemical microenvironment of a patient’s ileal mucosa with their clinical phenotype and genotype to identify factors favoring the growth and virulence of adherent and invasive E. coli (AIEC) linked to Crohn’s disease. We determined that the ileal niche of AIEC was characterized by inflammation, dysbiosis, coculture of Enterococcus, and oxidative stress. We discovered that mucosal metabolites supported general growth of ileal E. coli, with a selective effect of ethanolamine on AIEC that was augmented by cometabolism of ileitis-associated amino acids and glutathione and by symbiosis-associated fucose. This metabolic plasticity was facilitated by the eut and pdu microcompartments, amino acid metabolism, γ-glutamyl-cycle, and pleiotropic stress responses. We linked metabolism to virulence and found that ethanolamine and glutamine enhanced AIEC motility, infectivity, and proinflammatory responses in vitro. We connected use of ethanolamine to intestinal inflammation and L-fuculose phosphate aldolase (fucA) to symbiosis in AIEC monoassociated IL10^–/– mice. Collectively, we established that AIEC were pathoadapted to utilize mucosal metabolites associated with health and inflammation for growth and virulence, enabling the transition from symbiont to pathogen in a susceptible host.

Interobserver agreement of a gastric adenocarcinoma tumor regression grading system that incorporates assessment of lymph nodes

Perioperative chemotherapy is increasingly used in combination with surgery for the treatment of patients with locally advanced, resectable gastric cancer. Histologic tumor regression grade (TRG) has emerged as an important prognostic factor; however, a common standard for its evaluation is lacking. Moreover, the clinical significance of regressive changes in metastatic lymph nodes (LNs) remains unclear. We conducted an international study to examine the interobserver agreement of a TRG system that is based on the Becker system for the primary tumors and additionally incorporates regression grading in LNs. Twenty observers at different levels of experience evaluated the TRG in 60 histologic slides (30 primary tumors and 30 LNs) based on the following criteria: for primary tumors, grade 1 represented complete response (no residual tumor), grade 2 represented <10%, grade 3 represented 10-50%, and grade 4 represented >50% residual tumor, as described by Becker et al. For LNs, grade "a" represented complete, grade "b" represented partial, and grade "c" represented no regression. The interobserver agreement was estimated using the Kendall's coefficient of concordance (W). Regarding primary tumors, agreement was good irrespective of the level of experience, reaching a W-value of 0.70 overall, 0.71 among subspecialized, and 0.71 among nonsubspecialized observers. Regarding LNs, interobserver agreement was moderate to good, with W-values of 0.52 overall, 0.64 among subspecialized, and 0.45 among nonsubspecialized observers. These findings indicate that the combination of the Becker TRG system with a three-tiered grading of regression in LNs generates a system that is reproducible. Future studies should investigate whether the additional information of TRG in LNs adds to the prognostic value of histologic regression grading in gastric cancer specimens.

Multicenter, randomized phase II study of neoadjuvant pembrolizumab plus chemotherapy and chemoradiotherapy in esophageal adenocarcinoma (EAC)

4005

Background: Recent transformative studies in the treatment of EAC support adjuvant nivolumab for patients with residual disease following neoadjuvant chemoradiotherapy (CRT) (Checkmate 577) and pembrolizumab (P) with chemotherapy in untreated metastatic disease (Keynote 590). We hypothesized that pre-operative P combined with CRT can further improve outcomes in patients with locally advanced EAC. Methods: Patients with cT3-4Nx or T2N1 M0 EAC or gastroesophageal junction (GEJ) adenocarcinoma eligible for curative surgery were randomized (1:1) to receive either full-dose paclitaxel (T)/ carboplatin (C) or T/C + P induction therapy. All patients then received CRT with weekly T/C, RT 41.4Gy in 23 fractions, and P every 3 weeks. Following resection, patients received P for one year. The primary endpoint is rate of major pathologic response (MPR), defined as pathologic complete response or near complete response ( < 10% residual cancer), with 80% power and 0.1 one-sided significance level to detect the difference between a MPR proportion of 30% (historical control) and an alternative hypothesis of 47% (with preoperative P). Tissue was collected for tumor immune microenvironment (TIME) analysis including bulk and single cell RNA(scRNA) expression analysis, DNA sequencing, and flow cytometry. Results: From 8/4/17 to 10/26/20, 40 patients were enrolled: median age 68 [38-81], male 32, esophagus/GEJ type I (n = 16), GEJ II/III (n = 24). CRT was well tolerated, with no grade 3-4 adverse events attributed to P. Notable toxicity included grade 3-4 pneumonitis (13%), anastomotic leak (13%), infection (35%). In 31 evaluable patients to date, the MPR rate was 50.0% (95% CI, 32.7%-67.3%). 1-yr disease free survival was 100% for patients with MPR vs. 31.8% without MPR, p = 0.002. Esophageal/GEJ type I cancers had a significantly higher MPR rate when compared with GEJ type II/III (76.9% vs 37.5%, p = 0.03). scRNA seq on > 100,000 tumor cells revealed EAC/GEJ type I had higher infiltration of activated dendritic cells (p = 0.12), whereas GEJ tumors have significantly higher infiltration of activated B cells (p = 0.02). Conclusions: The addition of P to preoperative CRT for EAC is safe and associated with a significantly higher MPR rate compared to historical data. We found MPR to be significantly enriched in EAC/GEJ type I tumors compared with GEJ II/III, associated with important differences in the baseline tumor immune microenvironment. Clinical trial information: NCT02998268.

Early Detection for Colorectal Cancer: ASCO Resource-Stratified Guideline

PURPOSE

To provide resource-stratified, evidence-based recommendations on the early detection of colorectal cancer in four tiers to clinicians, patients, and caregivers.

METHODS

American Society of Clinical Oncology convened a multidisciplinary, multinational panel of medical oncology, surgical oncology, surgery, gastroenterology, health technology assessment, cancer epidemiology, pathology, radiology, radiation oncology, and patient advocacy experts. The Expert Panel reviewed existing guidelines and conducted a modified ADAPTE process and a formal consensus-based process with additional experts (Consensus Ratings Group) for two round(s) of formal ratings.

RESULTS

Existing sets of guidelines from eight guideline developers were identified and reviewed; adapted recommendations form the evidence base. These guidelines, along with cost-effectiveness analyses, provided evidence to inform the formal consensus process, which resulted in agreement of 75% or more.

CONCLUSION

In nonmaximal settings, for people who are asymptomatic, are ages 50 to 75 years, have no family history of colorectal cancer, are at average risk, and are in settings with high incidences of colorectal cancer, the following screening options are recommended: guaiac fecal occult blood test and fecal immunochemical testing (basic), flexible sigmoidoscopy (add option in limited), and colonoscopy (add option in enhanced). Optimal reflex testing strategy for persons with positive screens is as follows: endoscopy; if not available, barium enema (basic or limited). Management of polyps in enhanced is as follows: colonoscopy, polypectomy; if not suitable, then surgical resection. For workup and diagnosis of people with symptoms, physical exam with digital rectal examination, double contrast barium enema (only in basic and limited); colonoscopy; flexible sigmoidoscopy with biopsy (if contraindication to latter) or computed tomography colonography if contraindications to two endoscopies (enhanced only).

Treatment of Patients With Early-Stage Colorectal Cancer: ASCO Resource-Stratified Guideline

PURPOSE

To provide resource-stratified, evidence-based recommendations on the treatment and follow-up of patients with early-stage colorectal cancer.

METHODS

ASCO convened a multidisciplinary, multinational Expert Panel that reviewed existing guidelines and conducted a modified ADAPTE process and a formal consensus process with additional experts for one round of formal ratings.

RESULTS

Existing sets of guidelines from 12 guideline developers were identified and reviewed; adapted recommendations from six guidelines form the evidence base and provide evidence to inform the formal consensus process, which resulted in agreement of 75% or more on all recommendations.

RECOMMENDATIONS

For nonmaximal settings, the recommended treatments for colon cancer stages nonobstructing, I-IIA: in basic and limited, open resection; in enhanced, adequately trained surgeons and laparoscopic or minimally invasive surgery, unless contraindicated. Treatments for IIB-IIC: in basic and limited, open en bloc resection following standard oncologic principles, if not possible, transfer to higher-level facility; in emergency, limit to life-saving procedures; in enhanced, laparoscopic en bloc resection, if not possible, then open. Treatments for obstructing, IIB-IIC: in basic, resection and/or diversion; in limited or enhanced, emergency surgical resection. Treatment for IIB-IIC with left-sided: in enhanced, may place colonic stent. Treatment for T4N0/T3N0 high-risk features or stage II high-risk obstructing: in enhanced, may offer adjuvant chemotherapy. Treatment for rectal cancer cT1N0 and cT2n0: in basic, limited, or enhanced, total mesorectal excision principles. Treatment for cT3n0: in basic and limited, total mesorectal excision, if not, diversion. Treatment for high-risk patients who did not receive neoadjuvant chemotherapy: in basic, limited, or enhanced, may offer adjuvant therapy. Treatment for resectable cT3N0 rectal cancer: in enhanced, base neoadjuvant chemotherapy on preoperative factors. For post-treatment surveillance, a combination of medical history, physical examination, carcinoembryonic antigen testing, imaging, and endoscopy is performed. Frequency depends on setting. Maximal setting recommendations are in the guideline. Additional information can be found at www.asco.org/resource-stratified-guidelines.

NOTICE

It is the view of the American Society of Clinical Oncology that health care providers and health care system decision makers should be guided by the recommendations for the highest stratum of resources available. The guidelines are intended to complement but not replace local guidelines.

Abstract 274: Early-onset colorectal cancer is distinct from traditional colorectal cancer

Background & Objective: Colorectal cancer (CRC) is the fourth most commonly diagnosed cancer worldwide, responsible for over 700,000 deaths annually. Although CRC rates have declined 3.1%/year annually over the past decade, annual incidence rates of CRC among patients between 20-49 years old have increased by more than 1.4% per year over the same time period and these early-onset CRCs (E-CRC) now comprise 10-18% of newly diagnosed cases.

Our hypothesis is that E-CRC represents a distinct subtype of CRC with unique drivers. To examine this, we analyzed national data sources such as the SEER database, the Behavioral Risk Factor Surveillance Survey (BRFSS), and the Cancer Genome Atlas (TCGA) to characterize the epidemiology and genetics differences between early onset CRC (E-CRC) and typical CRC (T-CRC).

Methods: The SEER database was analyzed to characterize the clinical and pathological differences between E-CRC patients (20-49 years) and T-CRC group (&gt; 50 years). We compared rates of age-adjusted CRC with known lifestyle risk factors using population data from the BRFSS. Based on differences in clinical presentation and anatomical location we hypothesized that there are underlying molecular differences between E-CRCs and T-CRC that may explain these differences. To investigate this we analyzed the TCGA CRC dataset for genomic markers that can distinguish between E-CRC and T-CRC tumors.

Results: E-CRC incidence has risen at an annual rate of 1.4% per year from 2000-2011, whereas T-CRC incidence has declined by 3.1% per year among patients 50 years or older during the same period.

Relative to T-CRC, E-CRC rates are significantly more prevalent in the Black population than the White or Hispanic populations.

Anatomical location of E-CRC is significantly increased towards the distal colon when compared to T-CRC locations suggesting a distinct etiology.

Analysis of risk factors confirmed that U.S counties with high rates of diabetes, obesity and smoking were significantly correlated with higher T-CRC rates. However, no such correlations were observed for E-CRC rates.

Analysis of the limited number of E-CRC in the TCGA cohort identified a number of known oncogenes that are suggestive of distinct E-CRC tumorigenesis.

Conclusions: Our results suggest that E-CRC appears to be distinct from T-CRC. Young patients with CRC represent a distinct patient group with unique epidemiology and mechanisms of disease development. The increase in left sided colon and rectal cancers is consistent with earlier reports and although the underlying reasons are unknown, they are suggestive of differences in tumor genesis and mutational characteristics. To follow up on this hypothesis we are performing additional genetic and epigenetic characterization of E-CRC and matching T-CRC samples collected at Weill Cornell.

Citation Format: Doron Betel, Heather Yeo, Rhonda Yantiss, Xi E. Zheng, Jonathan S. Abelson, Manish A. Shah. Early-onset colorectal cancer is distinct from traditional colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 274. doi:10.1158/1538-7445.AM2017-274

Phase I Study of Epigenetic Priming with Azacitidine Prior to Standard Neoadjuvant Chemotherapy for Patients with Resectable Gastric and Esophageal Adenocarcinoma: Evidence of Tumor Hypomethylation as an Indicator of Major Histopathologic Response

Purpose: Epigenetic silencing of tumor suppressor genes (TSG) is an acquired abnormality observed in cancer and is prototypically linked to DNA methylation. We postulated that pretreatment (priming) with 5-azacitidine would increase the efficacy of chemotherapy by reactivating TSGs. This study was conducted to identify a tolerable dose of 5-azacitidine prior to EOX (epirubicin, oxaliplatin, capecitabine) neoadjuvant chemotherapy in patients with locally advanced esophageal/gastric adenocarcinoma (EGC).Experimental Design: Eligible patients had untreated, locally advanced, resectable EGC, ECOG 0-2, and adequate organ function. 5-Azacitidine (V, 75 mg/m²) was given subcutaneously for 3 (dose level, DL 1) or 5 (DL 2) days prior to each 21-day cycle of EOX (E, 50 mg/m²; O, 130 mg/m²; X, 625 mg/m² twice daily for 21 days). Standard 3+3 methodology guided V dose escalation. DNA methylation at control and biomarker regions was measured by digital droplet, bisulfite qPCR in tumor samples collected at baseline and at resection.Results: All subjects underwent complete resection of residual tumor (R0). Three of the 12 patients (25%) achieved a surgical complete response and 5 had partial responses. The overall response rate was 67%. The most common toxicities were gastrointestinal and hematologic. Hypomethylation of biomarker genes was observed at all dose levels and trended with therapeutic response.Conclusions: Neoadjuvant VEOX was well-tolerated with significant clinical and epigenetic responses, with preliminary evidence that priming with V prior to chemotherapy may augment chemotherapy efficacy. The recommended phase II trial schedule is 5-azacitidine 75 mg/m² for 5 days followed by EOX chemotherapy every 21 days. Clin Cancer Res; 23(11); 2673-80. ©2016 AACR.

Multidrug resistance is common in Escherichia coli associated with ileal Crohn's disease

BACKGROUND

Escherichia coli is increasingly implicated in the pathogenesis of ileal Crohn's disease (ICD), offering a potential therapeutic target for disease management. Empirical antimicrobial targeting of ileal E. coli has advantages of economy and speed of implementation, but relies on uniform susceptibility of E. coli to routinely selected antimicrobials to avoid apparent treatment failure. Therefore, we examined the susceptibility of ileal E. coli to such antimicrobials.

METHODS

E. coli from 32 patients with ICD and 28 with normal ileum (NI) were characterized by phylogroup, pathotype, antimicrobial susceptibility, and presence of antimicrobial resistance genes.

RESULTS

In all, 17/32 ICD and 12/28 NI patients harbored ≥ 1 E. coli strain; 10/24 E. coli strains from ICD and 2/14 from NI were nonsuscepti-ble to ≥ 1 antimicrobial in ≥ 3 categories (multidrug-resistant). Resistance to amoxicillin/clavulanic-acid, cefoxitin, chloramphenicol, ciprofloxa-cin, gentamicin, and rifaximin was restricted to ICD, with 10/24 strains from 8/17 patients resistant to ciprofloxacin or rifaximin (P < 0.01). Adherent-invasive E. coli (AIEC) were isolated from 8/32 ICD and 5/28 NI, and accounted for 54% and 43% of E. coli strains in these groups. In all, 8/13 AIEC strains from ICD (6/8 patients) versus 2/6 NI (2/5 patients) showed resistance to the macrophage-penetrating antimicrobials ciprofloxacin, clarithromycin, rifampicin, tetracycline, and trimethoprim/sulfamethoxazole. Resistance was associated with tetA, tetB, tetC, bla-(TEM), bla(oxa)-1, sulI, sulII, dhfrI, dhfrVII, ant(3″)-Ia, and catI genes and prior use of rifaximin (P < 0.01).

CONCLUSIONS

ICD-associated E. coli frequently manifest resistance to commonly used antimicrobials. Clinical trials of antimicrobials against E. coli in ICD that are informed by susceptibility testing, rather than empirical selection, are more likely to demonstrate valid outcomes of such therapy.

Abstract 1634: Metabolomic profiling for early detection of colorectal neoplasia

Introduction: Colorectal cancer (CRC) is the 3rd leading cause of cancer-related deaths in the world. Colonoscopy is widely used for early detection and removal of colorectal neoplasia to prevent CRC. However, it is both invasive and costly underscoring the need for new strategies to identify subjects for whom colonoscopy is most appropriate. Metabolomics is a high throughput method of detecting small molecules which provides a platform for identifying novel biomarkers of colorectal neoplasia. In this study, we investigated whether metabolic changes could be identified in the feces and plasma in a model of experimental CRC. Methods: Five week old male A/J mice were administered six weekly intraperitoneal injections of either azoxymethane (AOM) (10mg/kg) (n=40) or 0.9% saline (n=35). Following injections, feces, plasma and tumor tissue or normal colonic mucosa were collected and stored at −80oC for metabolomic analysis. Five mice from the AOM injected group were sacrificed at each of three time points (three, five and seven weeks after the last injection) to assess tumor burden. UPLC/MS/MS and GC/MS were used to quantify metabolite levels in feces, plasma and tissue. Results: Histological analysis of tumor burden in the colon showed a progressive increase as a function of time after AOM administration. Metabolomic analysis revealed a large number of significantly changed metabolite levels in both the feces and plasma during colon carcinogenesis. These included amino acids and peptides in feces as well as bile acids in the plasma. A select number of these metabolites were found to progressively change as a function of time in both feces and plasma in relation to increased tumor burden. Significantly, certain metabolites changed in the same direction in feces and tumor tissue, plasma and tumor tissue as well as across all three matrices, suggesting that these may be tumor-derived. For example, samples from AOM injected mice showed increased levels of sarcosine and 2-hydroxyglutarate, metabolites previously implicated in prostate cancer and gliomas/AML, respectively. Conclusions: This study demonstrates the potential utility of metabolomic analyses for the early detection of colorectal neoplasia. Additionally, the finding of increased levels of two onco-metabolites (sarcosine, 2-hydroxyglutarate) in colorectal neoplasia suggests their potential involvement in colon carcinogenesis. Future studies in humans will be required to determine the significance of these findings.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1634. doi:1538-7445.AM2012-1634

Multifocal granular cell tumor presenting as an esophageal stricture

INTRODUCTION

Granular cell tumors are uncommonly found in the gastrointestinal tract with slow progression and are usually benign though they may have propensity for malignant transformation. Initially attributed to neuronal origin through immunohistochemistry, there has been controversy with increasing reports of granular cell tumors of non-neural origin.

CASE REPORT

We report a case of multifocal granular cell tumor involving the esophagus and stomach in a young female with history of dysphagia for 9 years with worsening symptoms. She had been managed at another facility with repeated dilations for presumed benign peptic stricture. Radial endosonography (EUS) of the proximal end of stricture showed a posterior submucosal esophageal mass that was heterogeneous and invaded into the muscularis propria. Fine-needle aspiration (FNA) showed large cells with granular cytoplasm along with spindle nuclei. Cells were initially checked for CD117 stain alone and found to be negative. A follow-up CT-guided core needle biopsy revealed similar granular cells that were positive for S-100. She underwent a two-stage transhiatal esophagogastrectomy as the tumor circumferentially involved the cervical esophagus and was adherent to the trachea and recurrent laryngeal nerve bilaterally. At surgery, there were two additional foci palpable in the proximal stomach.

DISCUSSION AND CONCLUSION

As these tumors may have potential for malignant transformation and locoregional invasion, they should be considered while evaluating submucosal lesions of the esophagus even in young patients. A large number of granular cell tumors may be missed in the absence of S-100 staining, which should be requested when granular cells are seen on cytology obtained by EUS FNA as this can be a minimally invasive diagnostic modality for these tumors. Other foci should be sought at surgery as they have a propensity for locoregional spread.

Culture independent analysis of ileal mucosa reveals a selective increase in invasive Escherichia coli of novel phylogeny relative to depletion of Clostridiales in Crohn's disease involving the ileum

Intestinal bacteria are implicated increasingly as a pivotal factor in the development of Crohn's disease, but the specific components of the complex polymicrobial enteric environment driving the inflammatory response are unresolved. This study addresses the role of the ileal mucosa-associated microflora in Crohn's disease. A combination of culture-independent analysis of bacterial diversity (16S rDNA library analysis, quantitative PCR and fluorescence in situ hybridization) and molecular characterization of cultured bacteria was used to examine the ileal mucosa-associated flora of patients with Crohn's disease involving the ileum (13), Crohn's disease restricted to the colon (CCD) (8) and healthy individuals (7). Analysis of 16S rDNA libraries constructed from ileal mucosa yielded nine clades that segregated according to their origin (P<0.0001). 16S rDNA libraries of ileitis mucosa were enriched in sequences for Escherichia coli (P<0.001), but relatively depleted in a subset of Clostridiales (P<0.05). PCR of mucosal DNA was negative for Mycobacterium avium subspecies paratuberculosis, Shigella and Listeria. The number of E. coli in situ correlated with the severity of ileal disease (rho 0.621, P<0.001) and invasive E. coli was restricted to inflamed mucosa. E. coli strains isolated from the ileum were predominantly novel in phylogeny, displayed pathogen-like behavior in vitro and harbored chromosomal and episomal elements similar to those described in extraintestinal pathogenic E. coli and pathogenic Enterobacteriaceae. These data establish that dysbiosis of the ileal mucosa-associated flora correlates with an ileal Crohn's disease (ICD) phenotype, and raise the possibility that a selective increase in a novel group of invasive E. coli is involved in the etiopathogenesis to Crohn's disease involving the ileum.

Role of therapy or monitoring in preventing progression to gastric cancer

It is generally accepted that intestinal-type gastric adenocarcinoma arises through a multistep process originating with chronic gastritis, progressing through stages of atrophy, intestinal metaplasia, and dysplasia and finally invasive carcinoma. This sequential process, known as the "Correa cascade" is in many instances initiated by Helicobacter pylori infection and perpetuated by a number of environmental and host factors. Given that the development of carcinoma can be the end point of this sequential process, there is great interest in determining which if any of these steps may be reversible. Clinical studies have shown that the eradication of H. pylori can lead to resolution of chronic gastritis, and a few studies have suggested some improvement in gastric atrophy. Intestinal metaplasia, however, does not appear to be as reversible. Nevertheless, results of several intriguing studies of high-risk populations support the notion that eradication of H. pylori may decrease or delay progression to gastric carcinoma despite the inability to reverse all mucosal damage. The applicability of these findings to low-risk countries such as the United States and the United Kingdom remain uncertain. Currently, in the United States, there is no widely accepted screening program for H. pylori infection in asymptomatic individuals, and consensus regarding surveillance for gastric intestinal metaplasia or dysplasia is lacking. The purpose of this report is to evaluate the available data regarding the epidemiology of H. pylori and associated carcinoma, discuss relevant human and animal data that address eradication strategies in the prevention of gastric carcinoma, and finally discuss current recommendations regarding screening programs aimed at high-risk populations.