Nfe2l2/NRF2 deletion attenuates tumorigenesis and increases bacterial diversity in a mouse model of Lynch syndrome.

Lynch syndrome (LS) is the most prevalent heritable form of colorectal cancer (CRC). Its early onset and high lifetime risk for CRC emphasize the necessity for effective chemoprevention. NFE2L2 (NRF2) is often considered a potential druggable target, and many chemopreventive compounds do induce NRF2. However, while NRF2 counteracts oxidative stress, it is also overexpressed in CRC and may promote tumorigenesis. Herein, we evaluated the role of NRF2 in prevention of LS-associated neoplasia. We found an increased levels of NRF2 in intestinal epithelia of mice with intestinal epithelial-specific Msh2 deletion (MSH2ΔIEC) as compared to C57BL/6 (wild type) mice, as well as an increase in downstream NRF2 targets Nqo1 and Gclc. Likewise, NRF2 levels were increased in human MSH2-deficient LS tumors compared to healthy controls. In silico analysis of a publicly accessible RNA-sequencing LS dataset also found an increase in downstream NRF2 targets. Upon crossing MSH2ΔIEC with Nrf2null mice (MSH2ΔIECNrf2null), we unexpectedly found reduced tumorigenesis in MSH2ΔIECNrf2null compared to MSH2ΔIEC after 40 weeks. This occurred despite an increase in oxidative damage in MSH2ΔIECNrf2null mice. Loss of NRF2 impaired proliferation as seen by Ki67 intestinal staining and in organoid cultures. This was accompanied by diminished WNT/ß-catenin signaling. Apoptosis was unaffected. Microbial alpha-diversity increased over time with loss of NRF2 based upon 16S rRNA gene amplicon sequencing of murine fecal samples. Altogether, we show that NRF2 protein levels are increased in MSH2-deficiency and associated neoplasia, but loss of NRF2 attenuates tumorigenesis. Activation of NRF2 may not be a feasible strategy for chemoprevention in LS.

A prospective observational multicentric clinical trial to evaluate microscopic examination of acid-fast bacilli in sputum by artificial intelligence-based microscopy system.

Microscopy-based tuberculosis (TB) diagnosis i.e., Ziehl-Neelsen (ZN) stained smear screening still remains the primary diagnostic method in resource poor and high TB burden countries, however itrequires considerable experience and is bound to human errors. In remote areas, wherever expert microscopist is not available, timely diagnosis at initial level is not possible. Artificial intelligence (AI)-based microscopy may be a solution to this problem. A prospective observational multi-centric clinical trial to evaluate microscopic examination of acid-fast bacilli (AFB) in sputum by the AI based system was done in three hospitals in Northern India. Sputum samples from 400 clinically suspected cases of pulmonary tuberculosis were collected from three centres. Ziehl-Neelsen staining of smears was done. All the smears were observed by 3 microscopist and the AI based microscopy system. AI based microscopy was found to have a sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of 89.25%, 92.15%, 75.45%, 96.94%, 91.53% respectively. AI based sputum microscopy has an acceptable degree of accuracy, PPV, NPV, specificity and sensitivity and thus may be used as a screening tool for the diagnosis of pulmonary tuberculosis.

Atypical enteropathogenic E. coli are associated with disease activity in ulcerative colitis.

With increasing urbanization and industrialization, the prevalence of inflammatory bowel diseases (IBDs) has steadily been rising over the past two decades. IBD involves flares of gastrointestinal (GI) inflammation accompanied by microbiota perturbations. However, microbial mechanisms that trigger such flares remain elusive. Here, we analyzed the association of the emerging pathogen atypical enteropathogenic E. coli (aEPEC) with IBD disease activity. The presence of diarrheagenic E. coli was assessed in stool samples from 630 IBD patients and 234 age- and sex-matched controls without GI symptoms. Microbiota was analyzed with 16S ribosomal RNA gene amplicon sequencing, and 57 clinical aEPEC isolates were subjected to whole-genome sequencing and in vitro pathogenicity experiments including biofilm formation, epithelial barrier function and the ability to induce pro-inflammatory signaling. The presence of aEPEC correlated with laboratory, clinical and endoscopic disease activity in ulcerative colitis (UC), as well as microbiota dysbiosis. In vitro, aEPEC strains induce epithelial p21-activated kinases, disrupt the epithelial barrier and display potent biofilm formation. The effector proteins espV and espG2 distinguish aEPEC cultured from UC and Crohn's disease patients, respectively. EspV-positive aEPEC harbor more virulence factors and have a higher pro-inflammatory potential, which is counteracted by 5-ASA. aEPEC may tip a fragile immune-microbiota homeostasis and thereby contribute to flares in UC. aEPEC isolates from UC patients display properties to disrupt the epithelial barrier and to induce pro-inflammatory signaling in vitro.

Role of the E3 ubiquitin-ligase Hakai in intestinal inflammation and cancer bowel disease.

The E3 ubiquitin-ligases are important for cellular protein homeostasis and their deregulation is implicated in cancer. The E3 ubiquitin-ligase Hakai is involved in tumour progression and metastasis, through the regulation of the tumour suppressor E-cadherin. Hakai is overexpressed in colon cancer, however, the implication in colitis-associated cancer is unknown. Here, we investigated the potential role of Hakai in intestinal inflammation and cancer bowel disease. Several mouse models of colitis and associated cancer were used to analyse Hakai expression by immunohistochemistry. We also analysed Hakai expression in patients with inflamed colon biopsies from ulcerative colitis and Crohn's disease. By Hakai interactome analysis, it was identified Fatty Acid Synthase (FASN) as a novel Hakai-interacting protein. Moreover, we show that Hakai induces FASN ubiquitination and degradation via lysosome, thus regulating FASN-mediated lipid accumulation. An inverse expression of FASN and Hakai was detected in inflammatory AOM/DSS mouse model. In conclusion, Hakai regulates FASN ubiquitination and degradation, resulting in the regulation of FASN-mediated lipid accumulation, which is associated to the development of inflammatory bowel disease. The interaction between Hakai and FASN may be an important mechanism for the homeostasis of intestinal barrier function and in the pathogenesis of this disease.

Intravenous iron is non-inferior to oral iron regarding cell growth and iron metabolism in colorectal cancer associated with iron-deficiency anaemia.

Oral iron promotes intestinal tumourigenesis in animal models. In humans, expression of iron transport proteins are altered in colorectal cancer. This study examined whether the route of iron therapy alters iron transport and tumour growth. Colorectal adenocarcinoma patients with pre-operative iron deficiency anaemia received oral ferrous sulphate (n = 15), or intravenous ferric carboxymaltose (n = 15). Paired (normal and tumour tissues) samples were compared for expression of iron loading, iron transporters, proliferation, apoptosis and Wnt signalling using immunohistochemistry and RT-PCR. Iron loading was increased in tumour and distributed to the stroma in intravenous treatment and to the epithelium in oral treatment. Protein and mRNA expression of proliferation and iron transporters were increased in tumours compared to normal tissues but there were no significant differences between the treatment groups. However, intravenous iron treatment reduced ferritin mRNA levels in tumours and replenished body iron stores. Iron distribution to non-epithelial cells in intravenous iron suggests that iron is less bioavailable to tumour cells. Therefore, intravenous iron may be a better option in the treatment of colorectal cancer patients with iron deficiency anaemia due to its efficiency in replenishing iron levels while its effect on proliferation and iron metabolism is similar to that of oral iron treatment.

Mucosal Biofilms Are an Endoscopic Feature of Irritable Bowel Syndrome and Ulcerative Colitis.

BACKGROUND & AIMS: Irritable bowel syndrome (IBS) and inflammatory bowel diseases result in a substantial reduction in quality of life and a considerable socioeconomic impact. In IBS, diagnosis and treatment options are limited, but evidence for involvement of the gut microbiome in disease pathophysiology is emerging. Here we analyzed the prevalence of endoscopically visible mucosal biofilms in gastrointestinal disease and associated changes in microbiome composition and metabolism. METHODS: The presence of mucosal biofilms was assessed in 1426 patients at 2 European university-based endoscopy centers. One-hundred and seventeen patients were selected for in-depth molecular and microscopic analysis using 16S ribosomal RNA gene amplicon-sequencing of colonic biopsies and fecal samples, confocal microscopy with deep learning-based image analysis, scanning electron microscopy, metabolomics, and in vitro biofilm formation assays. RESULTS: Biofilms were present in 57% of patients with IBS and 34% of patients with ulcerative colitis compared with 6% of controls (P < .001). These yellow-green adherent layers of the ileum and right-sided colon were microscopically confirmed to be dense bacterial biofilms. 16S-sequencing links the presence of biofilms to a dysbiotic gut microbiome, including overgrowth of Escherichia coli and Ruminococcus gnavus. R. gnavus isolates cultivated from patient biofilms also formed biofilms in vitro. Metabolomic analysis found an accumulation of bile acids within biofilms that correlated with fecal bile acid excretion, linking this phenotype with a mechanism of diarrhea. CONCLUSIONS: The presence of mucosal biofilms is an endoscopic feature in a subgroup of IBS and ulcerative colitis with disrupted bile acid metabolism and bacterial dysbiosis. They provide novel insight into the pathophysiology of IBS and ulcerative colitis, illustrating that biofilm can be seen as a tipping point in the development of dysbiosis and disease.

The food additive EDTA aggravates colitis and colon carcinogenesis in mouse models.

Inflammatory bowel disease is a group of conditions with rising incidence caused by genetic and environmental factors including diet. The chelator ethylenediaminetetraacetate (EDTA) is widely used by the food and pharmaceutical industry among numerous other applications, leading to a considerable environmental exposure. Numerous safety studies in healthy animals have revealed no relevant toxicity by EDTA. Here we show that, in the presence of intestinal inflammation, EDTA is surprisingly capable of massively exacerbating inflammation and even inducing colorectal carcinogenesis at doses that are presumed to be safe. This toxicity is evident in two biologically different mouse models of inflammatory bowel disease, the AOM/DSS and the IL10-/- model. The mechanism of this effect may be attributed to disruption of intercellular contacts as demonstrated by in vivo confocal endomicroscopy, electron microscopy and cell culture studies. Our findings add EDTA to the list of food additives that might be detrimental in the presence of intestinal inflammation, but the toxicity of which may have been missed by regulatory safety testing procedures that utilize only healthy models. We conclude that the current use of EDTA especially in food and pharmaceuticals should be reconsidered. Moreover, we suggest that intestinal inflammatory models should be implemented in the testing of food additives to account for the exposure of this primary organ to environmental and dietary stress.

Iron deficiency-induced thrombocytosis increases thrombotic tendency in rats.

Iron deficiency (ID) is globally prevalent, and apart from anemia is associated with thrombocytosis. While considered benign, studies linking thrombotic events with prior ID anemia suggest otherwise. Herein we used animal models to assess the influence of ID on thrombotic tendency. Sprague-Dawley rats were fed control or iron deficient diets and ferric carboxymaltose was used to reverse ID. Thrombosis was induced via stenosis of the inferior vena cava or damage to the right carotid artery using ferric chloride. Thrombi were evaluated histologically and via high frequency ultrasound in the venous model. ID consistently induced thrombocytosis alongside anemia. Venous thrombus growth and final dimensions in both arterial and venous thrombi were largest in ID. In both models, platelet numbers correlated with the final thrombus size, with ID thrombi having the largest platelet areas. Platelet function was also evaluated in surgically naive rats. Coagulability on thromboelastography and hemostasis on tail transection were augmented in ID. Platelet and plasma P-selectin expression were both higher in ID. Platelet adhesion and aggregation in ID was impaired under shear flow but was intact on static assays. Iron replacement therapy reversed all ID-related changes in hematological parameters, thrombus dimensions, and platelet assays. In summary, ID alone increases thrombotic tendency. Iron replacement therapy reverses these changes, making it a viable strategy for prevention of ID-related thrombotic disease. This may be of importance in patients with chronic illnesses which may already be at increased risk for thrombosis such as inflammatory bowel disease, chronic kidney disease, or cancer.

A Novel PAK1-Notch1 Axis Regulates Crypt Homeostasis in Intestinal Inflammation.

BACKGROUND & AIMS: p21-activated kinase-1 (PAK1) belongs to a family of serine-threonine kinases and contributes to cellular pathways such as nuclear factor-κB (NF-κB), mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT), and Wingless-related integration site(Wnt)/ß-catenin, all of which are involved in intestinal homeostasis. Overexpression of PAK1 is linked to inflammatory bowel disease as well as colitis-associated cancer (CAC), and similarly was observed in interleukin (IL)10 knockout (KO) mice, a model of colitis and CAC. Here, we tested the effects of PAK1 deletion on intestinal inflammation and carcinogenesis in IL10 KO mice. METHODS: IL10/PAK1 double-knockout (DKO) mice were generated and development of colitis and CAC was analyzed. Large intestines were measured and prepared for histology or RNA isolation. Swiss rolls were stained with H&E and periodic acid-Schiff. Co-immunoprecipitation and immunofluorescence were performed using intestinal organoids, SW480, and normal human colon epithelial cells 1CT. RESULTS: When compared with IL10 KO mice, DKOs showed longer colons and prolonged crypts, despite having higher inflammation and numbers of dysplasia. Crypt hyperproliferation was associated with Notch1 activation and diminished crypt differentiation, indicated by a reduction of goblet cells. Gene expression analysis indicated up-regulation of the Notch1 target hairy and enhancer of split-1 and the stem cell receptor leucin-rich repeat-containing G-protein-coupled receptor 5 in DKO mice. Interestingly, the stem cell marker olfactomedin-4 was present in colonic tissue. Increased ß-catenin messenger RNA and cytoplasmic accumulation indicated aberrant Wnt signaling. Co-localization and direct interaction of Notch1 and PAK1 was found in colon epithelial cells. Notch1 activation abrogated this effect whereas silencing of PAK1 led to Notch1 activation. CONCLUSIONS: PAK1 contributes to the regulation of crypt homeostasis under inflammatory conditions by controlling Notch1. This identifies a novel PAK1-Notch1 axis in intestinal pathophysiology of inflammatory bowel disease and CAC.

Mesalamine and azathioprine modulate junctional complexes and restore epithelial barrier function in intestinal inflammation.

Disruption of mucosal structure and barrier function contribute to the pathogenesis of inflammatory bowel disease (IBD). Efficacy of therapy in IBD is based on endoscopic mucosal healing, which occurs by a dynamic interplay of epithelial cell regeneration, migration and differentiation. Both mesalamine (5-ASA) and azathioprine (AZTP) promote this process through mechanisms not clearly understood. We examined molecular pathways implicated in epithelial barrier function that were altered by 5-ASA and AZTP. Paracellular permeability induced by inflammatory mediators was mitigated by both compounds through restoration of cellular anchoring complexes. 5-ASA and AZTP induced rearrangement and membranous localization of junctional proteins and modulated genes involved in tight junctions. Intestinal organoids from wildtype-mice treated with TNF-α and IL-10- deficient-mice displayed impaired epithelial barrier with loss of membranous E-cadherin and reduced Desmoglein-2 expression. These effects were counteracted by 5-ASA and AZTP. Unlike AZTP that exhibited antiproliferative effects, 5-ASA promoted wound healing in colon epithelial cells. Both affected cellular senescence, cell cycle distribution and restricted cells in G1 or S phase without inducing apoptosis. This study provides mechanistic evidence that molecular actions of 5-ASA and AZTP on intestinal epithelia are fundamental in the resolution of barrier dysfunction.

Overt Increase of Oxidative Stress and DNA Damage in Murine and Human Colitis and Colitis-Associated Neoplasia.

Patients with inflammatory bowel disease (IBD) have a higher risk of developing colitis-associated-cancer (CAC); however, the underlying processes of disease progression are not completely understood. Here, the molecular processes of inflammation-driven colon carcinogenesis were investigated using IL10-deficient mice (IL10 KO). IL10 KO mice were euthanized after development of colitis and dysplasia. IHC was performed for markers of colitis-induced DNA damage (CIDD): oxidative DNA lesions (8-oxoG), double-strand breaks (DSB; γH2AX). and DSB repair. MSI, LOH (Trp53, Apc), and global methylation (CIMP) were assessed on microdissected tissue. Comet assay for DNA damage, immunofluorescence, and immunoblotting were performed on intestinal organoids from wild-type (WT) and IL10 KO mice. Sequential biopsies and surgical specimens from IBD and CAC patients were used for IHC analysis. Severity of inflammation correlated with number of dysplasia. 8-oxoG and γH2AX-positive cells were significantly increased in inflamed and dysplastic areas along with activation of DSB repair. The amount of positively stained cells strongly correlated with degree of inflammation (8-oxoG: R = 0.923; γH2AX: R = 0.858). Neither CIMP, MSI nor LOH was observed. Enhanced DSBs in IL10 KO organoids were confirmed by comet assay and increased expression of γH2AX. Human clinical specimens exhibited significantly higher γH2AX and 8-oxoG in IBD, dysplasia, and CAC compared with normal mucosa. These data indicate that inflammation-driven colon carcinogenesis in IL10 KO mice and IBD patients is associated with oxidative DNA damage and overt presence of DSB. Mol Cancer Res; 16(4); 634-42. ©2018 AACR.

p-21 Activated Kinase as a Molecular Target for Chemoprevention in Diabetes.

HYPOTHESIS: Anti-diabetic drugs modulate p-21 activated kinase (PAK) signaling. Introduction: Type 2 diabetes mellitus (T2DM) is a chronic inflammatory disease associated with increased cancer risk. PAK signaling is implicated in cellular homeostasis when regulated, and cancer when unrestrained. Recent reports provided a role for PAK signaling in glucose homeostasis, but the role of PAKs in the pathogenesis of T2DM is unknown. Here, we performed a mini-meta-analysis to explore if anti-diabetic drugs modify PAK signaling pathways, and provide insight regarding modulation of these pathways, to potentially reduce diabetes-associated cancer risk. Methods: PAK interacting partners in T2DM were identified using the online STRING database. Correlation studies were performed via systematic literature review to understand the effect of anti-diabetic drugs on PAK signaling. A mini-meta-analysis correlated multiple clinical studies and revealed the overall clinical response rate and percentage of adverse events in piogliazone (n = 53) and metformin (n = 91) treated patients with PAK-associated diseases. Results: A total of 30 PAK interacting partners were identified (10: reduced beta-cell mass; 10: beta-cell dysfunction; 10: obesity-insulin resistance), which were highly associated with Wnt, and G-protein signaling. The anti-diabetic drug metformin activated signaling pathways upstream; whereas pioglitazone inhibited pathways downstream of PAK. Overall, clinical response upon pioglitazone treatment was 53%. Seventy-nine percent of pioglitazone and 75% of metformin treated patients had adverse events. Pioglitazone reduced molecular-PAK biomarkers of proliferation (Ki67 and CyclinD1), and metformin had the opposite effect. Conclusions: PAK signaling in T2DM likely involves Wnt and G-protein signaling, which may be altered by the anti-diabetic drugs metformin and pioglitazone. Apart from the therapeutic limitations of adverse events, pioglitazone may be promising in chemoprevention. However long-term multi-centered studies, which initiate pioglitazone treatment early will be required to fully assess the full potential of these drugs.

Identification of PMN-released mutagenic factors in a co-culture model for colitis-associated cancer.

Microsatellite instability (MSI) is present in ulcerative colitis (UC) and colitis-associated colorectal cancers (CAC). Certain factors released by polymorphonuclear cells (PMNs) may drive mucosal frameshift mutations resulting in MSI and cancer. Here, we applied a co-culture system with PMNs and colon epithelial cells to identify such culprit factors. Subjecting HCT116 + chr3 and human colonic epithelial cells (HCEC)-1CT MSI-reporter cell lines harboring mono-, di- or tetranucleotide DNA repeats linked to enhanced green fluorescent protein (EGFP) to activated PMNs induced frameshift mutations within all repeats, as quantified by flow cytometry. Activated PMNs released superoxide and hydrogen peroxide (H2O2), as measured by lucigenin-amplified chemiluminescence and fluorometry, respectively. Catalase, which scavenges H2O2, reduced such PMN-induced MSI. The NADPH-oxidase inhibitor apocynin, which blocks the oxidative burst in PMNs, similarly inhibited PMN-induced MSI. A bead-based multiplex assay revealed that PMNs release a wide range of cytokines such as interleukin (IL)-8, IL-6 and tumor necrosis factor-α (TNF-α). In vitro, these cytokines increased MSI in colon epithelial cells, and the Janus kinase (JAK) inhibitor tofacitinib abolished IL-6-induced or PMN-induced MSI. Intracellular reactive oxygen species (ROS) formation, as measured by 2',7'-dichlorofluorescein diacetate (DCFDA) assay, was induced upon cytokine treatment. DNA oxidation upon IL-6 was present, as detected by formamidopyrimidine glycosylase (FPG)-modified comet assay. In conclusion, activated PMNs induce frameshift mutations in colon epithelial cells resulting in MSI. Both oxidative burst with release of ROS and PMN-secreted cytokines, such as IL-8, IL-6 or TNF-α, contribute to MSI. ROS scavengers and/or specific inhibitors of cytokine signaling may delay or prevent cancer development in the setting of colitis.

Fungal Rhinosinusitis: Microbiological and Histopathological Perspective.

INTRODUCTION: On the basis of histopathology Fungal Rhinosinusitis (FRS) is categorized into non-invasive (allergic fungal rhinosinusitis, fungal ball) and invasive (acute invasive, chronic invasive and granulomatous invasive fungal sinusitis). This differentiation helps to decide the treatment. Role of latest molecular methods such as PCR and conventional methods such as KOH microscopy and culture also needs to be evaluated. Therefore, in this study we planned to categorise fungal rhinosinusitis on the basis of histopathology and compare it with other methods such as PCR, culture and KOH microscopy. AIM: To analyse fungal rhinosinusitis cases by both histopathologically and microbiologically. MATERIALS AND METHODS: A total of 76 clinically suspected fungal rhinosinusitis cases were included in the study. The tissue of suspected cases were processed and examined by KOH microscopy, histopathologically, culture and PCR. Histopathological examination was done by PAS, GMS and H&E stain. RESULTS: FRS was diagnosed in 37 (48.68%) cases out of 76 clinically suspected cases of FRS. In which 17 (22.3%) cases were positive by direct microscopy, 21 (27.6%) by culture, 27 (35.5%) by PCR and 14 (18.42%) by histopathology. Approximately 14 cases of FRS were classified according to histopathology; 10 (71.3%) as non-invasive FRS. Out of these 10, 9 (64.2%) were classified as AFRS and 1 (7.14%) as fungal ball. Only 4 cases (28.5%) were diagnosed with invasive FRS. Out of these 4 cases, 2 (14.2%) were of chronic invasive fungal rhinosinusitis, 1 (7.14%) was of granulomatous invasive fungal rhinosinusitis and 1 (7.14%) was of acute fulminant invasive fungal rhinosinusitis. Allergic Fungal Rhinosinusitis (AFRS) is the most common type of FRS. Aspergillus flavus was found to be the most common fungi causing FRS. CONCLUSION: Diagnosis should not be based on the single method. It should be done by both histopathological and microbiological methods, especially for those cases which are difficult to diagnose.

Study on MICs of Tigecycline in Clinical Isolates of Carbapenem Resistant Enterobacteriaceae (CRE) at a Tertiary Care Centre in North India.

INTRODUCTION: Members of family Enterobacteriaceae are the most common Gram-negative bacteria isolated from clinical samples. Those Enterobacteriaceae which have acquired resistance to all ß-lactams antibiotics including the carbapenems are considered as Carbapenem Resistant Enterobacteriaceae (CRE). These CRE isolates are often resistant to most other classes of antimicrobials as well, making their treatment a great challenge. Tigecycline is one of the last resort antimicrobials against such multidrug resistant bacteria. Decreased tigecycline susceptibility mediated by efflux pump systems is being reported in clinical strains of Enterobacteriaceae. Minimum Inhibitory Concentration (MIC) data would prove useful in managing infections by these multidrug resistant bacteria and optimizing use of tigecycline. AIM: To evaluate the MIC values of tigecycline against carbapenem resistant Escherichia coli and Klebsiella pneumoniae isolates. MATERIALS AND METHODS: This prospective study was carried out from January 2015 to December 2015 at the Department of Microbiology, Era's Lucknow Medical College and Hospital (ELMCH), Lucknow, Uttar Pradesh, India. Antimicrobial susceptibility by disk diffusion (Kirby-bauer) was done for 491 E. coli and K. pneumoniae strains isolated from 1606 samples collected from patients admitted in various wards and ICUs. Imipenem, meropenem and ertapenem 10 µg disks were used for testing of sensitivity to carbapenems. In all isolates, Tigecycline 15 µg (Hi-Media) disk was used to screen for tigecycline resistance. In CRE isolates, MICs of tigecycline were determined by E-test (Ezy MIC TM TG strips, Hi Media) and interpreted using European Committee on Antimicrobial Susceptibility Testing (EUCAST) 2016 guidelines. RESULTS: Out of 491 isolates tested, 186 (37.9%) were found to be CRE showing resistance to at least one of the three carbapenems tested and these included 99 E.coli and 87 K. pneumoniae. Sensitivity pattern of these two bacterial isolates shows a high level of resistance to most classes of antimicrobials. MIC testing for tigecycline was carried out in 144 CRE isolates and tigecycline resistance (MIC >2 µg/ml) was seen in 12 (8.3%) isolates (eight K.pneumoniae and four E. coli). Eight other isolates were found to have MIC of 2 µg/ml and thus the overall prevalence of isolates with decreased susceptibility was 20 (13.9%). CONCLUSION: A high prevalence of carbapenem resistance coupled with high tigecycline MICs in clinical isolates of E.coli and K. pneumoniae highlights the judicious use of a combination of antimicrobials. Routine in vitro sensitivity testing to evaluate the clinical utility of tigecycline against such resistant Enterobacteriaceae is warranted.

HuR Small-Molecule Inhibitor Elicits Differential Effects in Adenomatosis Polyposis and Colorectal Carcinogenesis.

HuR is an RNA-binding protein implicated in immune homeostasis and various cancers, including colorectal cancer. HuR binding to AU-rich elements within the 3' untranslated region of mRNAs encoding oncogenes, growth factors, and various cytokines leads message stability and translation. In this study, we evaluated HuR as a small-molecule target for preventing colorectal cancer in high-risk groups such as those with familial adenomatosis polyposis (FAP) or inflammatory bowel disease (IBD). In human specimens, levels of cytoplasmic HuR were increased in colonic epithelial cells from patients with IBD, IBD-cancer, FAP-adenoma, and colorectal cancer, but not in patients with IBD-dysplasia. Intraperitoneal injection of the HuR small-molecule inhibitor MS-444 in AOM/DSS mice, a model of IBD and inflammatory colon cancer, augmented DSS-induced weight loss and increased tumor multiplicity, size, and invasiveness. MS-444 treatment also abrogated tumor cell apoptosis and depleted tumor-associated eosinophils, accompanied by a decrease in IL18 and eotaxin-1. In contrast, HuR inhibition in APCMin mice, a model of FAP and colon cancer, diminished the number of small intestinal tumors generated. In this setting, fecal microbiota, evaluated by 16S rRNA gene amplicon sequencing, shifted to a state of reduced bacterial diversity, with an increased representation of Prevotella, Akkermansia, and Lachnospiraceae Taken together, our results indicate that HuR activation is an early event in FAP-adenoma but is not present in IBD-dysplasia. Furthermore, our results offer a preclinical proof of concept for HuR inhibition as an effective means of FAP chemoprevention, with caution advised in the setting of IBD. Cancer Res; 77(9); 2424-38. ©2017 AACR.

Comparative evaluation of pan-fungal real-time PCR, galactomannan and (1-3)-ß-D-glucan assay for invasive fungal infection in paediatric cancer patients.

Limited specific data and investigations are available for the diagnosis of Invasive Fungal Infection (IFI) in paediatrics cancer patients. Three non-invasive tests; Platelia Aspergillus EIA for galactomannan (GM), ß-D-glucan (BDG) assay and pan-fungal real-time PCR for fungal DNA in blood were evaluated. One hundred twenty-five paediatrics cancer patients at the high risk of IFI were enrolled. Single blood and serum samples were evaluated by all the three methods. Patients were classified into 10 proven, 52 probable and 63 no IFI cases in accordance with EORTC MSG 2008 revised guidelines. The sensitivity, specificity, PPV and NPV of all the three tests in proven, probable and no IFIs cases were analysed singly and in combination. The sensitivity, specificity, PPV and NPV of GM, BDG and pan-fungal real-time PCR were: 87%, 61%, 81%, 69.5% for GM, 88%, 59.5%, 81%, 71.4% for BDG and 89%, 69.2%, 85%, 67.5% for PCR (95% CI). Among different combinations, best combination was found to be GM and PCR with sensitivity, specificity, PPV and NPV of 98.2%, 89.3%, 97.1% and 90% respectively. Single samples must be evaluated by combination of tests.

PAK1 promotes intestinal tumor initiation.

p21-activated kinase 1 (PAK1) is a serine/threonine kinase that is overexpressed in colorectal cancer. PAK1 is a target of mesalamine [5-aminosylicylic acid (5-ASA)], a common drug for the treatment of ulcerative colitis with prospective chemopreventive properties. Here, we investigated whether PAK1 deletion impedes tumorigenesis in murine intestinal cancer models. Ten-week-old APC(min) or APC(min)/PAK1(-/-) mice were monitored for 8 weeks, euthanized, and assessed for tumor number and size. Six- to 8-week-old PAK1(-/-) and wild-type (WT) mice received one 10 mg/kg intraperitoneal injection of azoxymethane (AOM) and four cycles of 1.7% dextran sodium sulfate (DSS) for 4 days followed by 14 days of regular water. Mice also received 5-ASA via diet. Tumor incidence and size was assessed via colonoscopy and pathology. Molecular targets of PAK1 and 5-ASA were evaluated via immunohistochemistry (IHC) in both models. PAK1 deletion reduced tumor multiplicity and tumor burden but did not alter average tumor size in APC(min) mice. IHC revealed that PAK1 deletion reduced p-AKT, ß-catenin, and c-Myc expression in APC(min) adenomas. Colonoscopy and pathologic analysis revealed that PAK1 deletion reduced tumor multiplicity without affecting tumor size in AOM/DSS-treated mice. 5-ASA treatment and PAK1 deletion impeded tumor multiplicity and dysplastic lesions in AOM/DSS mice. IHC further revealed that 5-ASA blocked ß-catenin signaling via inhibition of PAK1/p-AKT. These data indicate that PAK1 contributes to initiation of intestinal carcinogenesis.

IL10R2 Overexpression Promotes IL22/STAT3 Signaling in Colorectal Carcinogenesis.

The mucosal immune response in the setting of intestinal inflammation contributes to colorectal cancer. IL10 signaling has a central role in gut homeostasis and is impaired in inflammatory bowel disease (IBD). Out of two IL10 receptor subunits, IL10R1 and IL10R2, the latter is shared among the IL10 family of cytokines and activates STAT signaling. STAT3 is oncogenic in colorectal cancer; however, knowledge about IL10 signaling upstream of STAT3 in colorectal cancer is lacking. Here, expression of IL10 signaling genes was examined in matched pairs from normal and tumor tissue from colorectal cancer patients showing overexpression (mRNA, protein) of IL10R2 and STAT3 but not IL10R1. IL10R2 overexpression was related to microsatellite stability. Transient overexpression of IL10R2 in HT29 cells increased proliferation upon ligand activation (IL10 and IL22). IL22, and not IL10, phosphorylated STAT3 along with increased phosphorylation of AKT and ERK. A significantly higher expression of IL22R1 and IL10R2 was also confirmed in a separate cohort of colorectal cancer samples. IL22 expression was elevated in gut mucosa from patients with IBD and colitis-associated cancer, which also exhibited increased expression of IL22R1 but not its coreceptor IL10R2. Overall, these data indicate that overexpression of IL10R2 and STAT3 contributes to colorectal carcinogenesis in microsatellite-stable tumors through IL22/STAT3 signaling.

PAK1 modulates a PPARγ/NF-κB cascade in intestinal inflammation.

P21-activated kinases (PAKs) are multifunctional effectors of Rho GTPases with both kinase and scaffolding activity. Here, we investigated the effects of inflammation on PAK1 signaling and its role in colitis-driven carcinogenesis. PAK1 and p-PAK1 (Thr423) were assessed by immunohistochemistry, immunofluorescence, and Western blot. C57BL6/J wildtype mice were treated with a single intraperitoneal TNFα injection. Small intestinal organoids from these mice and from PAK1-KO mice were cultured with TNFα. NF-κB and PPARγ were analyzed upon PAK1 overexpression and silencing for transcriptional/translational regulation. PAK1 expression and activation was increased on the luminal intestinal epithelial surface in inflammatory bowel disease and colitis-associated cancer. PAK1 was phosphorylated upon treatment with IFNγ, IL-1ß, and TNFα. In vivo, mice administered with TNFα showed increased p-PAK1 in intestinal villi, which was associated with nuclear p65 and NF-κB activation. p65 nuclear translocation downstream of TNFα was strongly inhibited in PAK1-KO small intestinal organoids. PAK1 overexpression induced a PAK1-p65 interaction as visualized by co-immunoprecipitation, nuclear translocation, and increased NF-κB transactivation, all of which were impeded by kinase-dead PAK1. Moreover, PAK1 overexpression downregulated PPARγ and mesalamine recovered PPARγ through PAK1 inhibition. On the other hand PAK1 silencing inhibited NF-κB, which was recovered using BADGE, a PPARγ antagonist. Altogether these data demonstrate that PAK1 overexpression and activation in inflammation and colitis-associated cancer promote NF-κB activity via suppression of PPARγ in intestinal epithelial cells.