Anouk Dev

STAT3-Driven Upregulation of TLR2 Promotes Gastric Tumorigenesis Independent of Tumor Inflammation

Gastric cancer (GC) is associated with chronic inflammation; however, the molecular mechanisms promoting tumorigenesis remain ill defined. Using a GC mouse model driven by hyperactivation of the signal transducer and activator of transcription (STAT)3 oncogene, we show that STAT3 directly upregulates the epithelial expression of the inflammatory mediator Toll-like receptor (TLR)2 in gastric tumors. Genetic and therapeutic targeting of TLR2 inhibited gastric tumorigenesis, but not inflammation, characterized by reduced proliferation and increased apoptosis of the gastric epithelium. Increased STAT3 pathway activation and TLR2 expression were also associated with poor GC patient survival. Collectively, our data reveal an unexpected role for TLR2 in the oncogenic function of STAT3 that may represent a therapeutic target in GC.

Effect of donor age on survival of liver transplant recipients with hepatitis C virus infection.

Background. Chronic hepatitis C virus (HCV) infection is the most common indication for orthotopic liver transplantation (OLT) in the United States. Recent studies from selected centers have suggested that older donor age is associated with worse outcomes after transplantation for HCV. Methods. We analyzed the United Network for Organ Sharing Liver Transplant Registry database from April 1987 to March 2003 to examine predictors of death or retransplantation in patients with HCV. Univariate models for each predictor were evaluated. Factors significant in the univariate model were used to develop a multivariable model. Results. Of 6,956 patients meeting the inclusion/exclusion criteria, 1,527 (22.0%) died or received retransplants during the first year after transplant. Recipients with graft failure were older, had greater serum creatinine levels, and were more likely to require mechanical ventilation and hemodialysis before transplant. Donors of patients with graft failure were older and more likely to have diabetes mellitus. In the multivariable regression model, predictors of graft failure at 1 year were donor age, recipient age, recipient creatinine greater than 2 mg/dL, and the requirement for mechanical ventilation for the recipient. Conclusions. Both older donor age and older recipient age plus markers of severity of disease, including requirement for mechanical ventilation and renal insufficiency, are negatively associated with survival after liver transplantation. These factors should be considered when assessing OLT recipient and donor candidacy in patients with HCV.

Serum proteomic analysis focused on fibrosis in patients with hepatitis C virus infection

BackgroundDespite its widespread use to assess fibrosis, liver biopsy has several important drawbacks, including that is it semi-quantitative, invasive, and limited by sampling and observer variability. Non-invasive serum biomarkers may more accurately reflect the fibrogenetic process. To identify potential biomarkers of fibrosis, we compared serum protein expression profiles in patients with chronic hepatitis C (CHC) virus infection and fibrosis.MethodsTwenty-one patients with no or mild fibrosis (METAVIR stage F0, F1) and 23 with advanced fibrosis (F3, F4) were retrospectively identified from a pedigreed database of 1600 CHC patients. All samples were carefully phenotyped and matched for age, gender, race, body mass index, genotype, duration of infection, alcohol use, and viral load. Expression profiling was performed in a blinded fashion using a 2D polyacrylamide gel electrophoresis/LC-MS/MS platform. Partial least squares discriminant analysis and likelihood ratio statistics were used to rank individual differences in protein expression between the 2 groups.ResultsSeven individual protein spots were identified as either significantly increased (α2-macroglobulin, haptoglobin, albumin) or decreased (complement C-4, serum retinol binding protein, apolipoprotein A-1, and two isoforms of apolipoprotein A-IV) with advanced fibrosis. Three individual proteins, haptoglobin, apolipoprotein A-1, and α2-macroglobulin, are included in existing non-invasive serum marker panels.ConclusionBiomarkers identified through expression profiling may facilitate the development of more accurate marker algorithms to better quantitate hepatic fibrosis and monitor disease progression.

Correlation of FIBROSpect II with histologic and morphometric evaluation of liver fibrosis in chronic hepatitis C

BACKGROUND & AIMS Accurate disease staging in chronic hepatitis C (CHC) infection helps guide treatment and may provide prognostic information. Liver biopsies are invasive, costly, and associated with morbidity. We hypothesized that a noninvasive test of liver fibrosis can accurately stage liver fibrosis. We prospectively evaluated the FIBROSpect II (FSII) biomarker panel versus pathology assessment and a quantitative measure of fibrosis. METHODS Liver biopsy specimens and serum were obtained from 252 CHC patients, including 50 posttransplant, from 3 tertiary centers. Biopsy specimens were scored centrally and independently at each site, along with central quantification of fibrosis by digitized morphometry. Serum tests were performed blinded to clinical or histologic evaluation. RESULTS The mean biopsy specimen length was 1.95 +/- 0.87 cm; prevalence of stage F2 through F4 fibrosis was 77%. Agreement between central and site readings for individual stages was modest (k = 0.674), with concordant readings in 106 of 248 (43%) biopsy specimens. The area under the receiver operating characteristic curve for FSII and morphometry for stages F2 through F4 for concordant biopsy specimens were 0.823 and 0.728, respectively. Sensitivity and specificity for FSII were 83.5% and 66.7%, respectively, with an accuracy of 80.2%. The aspartate aminotransferase to platelet ratio index sensitivity and specificity for predicting F2 through F4 were 30.4% and 100%, respectively, the indeterminate rate was 40.4%, and the accuracy rate was 48.4%. The accuracy of FSII in concordant biopsy specimens in the posttransplant cohort was 73%. CONCLUSIONS Serum biomarkers can differentiate mild from moderate-to-severe fibrosis. This prospective study validates the performance characteristics of FSII in CHC patients and a posttransplant cohort. Assessing the diagnostic utility of biomarkers is limited by variability in methods to quantify fibrosis and poor interobserver agreement for histologic staging.

IL28B genotype is not useful for predicting treatment outcome in Asian chronic hepatitis B patients treated with pegylated interferon-α.

IL28B genotype predicts response to pegylated interferon (peg‐IFN)‐based therapy in chronic hepatitis C. However, the utility of IL28B genotyping in chronic hepatitis B (CHB) cohorts treated with peg‐IFN is unclear. It was investigated whether IL28B genotype is associated with peg‐IFN treatment outcomes in a predominantly Asian CHB cohort.

Ethnic and cultural determinants influence risk assessment for hepatitis C acquisition

Background and Aim:  In the developed world hepatitis C virus (HCV) infection is predominantly associated with sharing contaminated equipment between injecting drug users (IDU). In developing countries inadequately sterilized medical equipment, transmission of infected blood and cultural practices have been implicated. Accurate risk factor assessment is essential for education targeted at risk reduction in culturally diverse populations.

Nucleotide Oligomerization Domain 1 Enhances IFN-γ Signaling in Gastric Epithelial Cells during Helicobacter pylori Infection and Exacerbates Disease Severity

Virulent Helicobacter pylori strains that specifically activate signaling in epithelial cells via the innate immune molecule, nucleotide oligomerization domain 1 (NOD1), are more frequently associated with IFN-γ–dependent inflammation and with severe clinical outcomes (i.e., gastric cancer and peptic ulceration). In cell culture models, we showed that H. pylori activation of the NOD1 pathway caused enhanced proinflammatory signaling in epithelial cells in response to IFN-γ stimulation through the direct effects of H. pylori on two components of the IFN-γ signaling pathway, STAT1 and IFN regulatory factor 1 (IRF1). Specifically, H. pylori activation of the NOD1 pathway was shown to increase the levels of STAT1-Tyr701/Ser727 phosphorylation and IRF1 expression/synthesis in cells, resulting in enhanced production of the NOD1- and IFN-γ–regulated chemokines, IL-8– and IFN-γ–induced protein 10, respectively. Consistent with the notion that heightened proinflammatory signaling in epithelial cells may have an impact on disease severity, we observed significantly increased expression levels of NOD1, CXCL8, IRF1, and CXCL10 in human gastric biopsies displaying severe gastritis, when compared with those without gastritis (p < 0.05, p < 0.001, p < 0.01, and p < 0.05, respectively). Interestingly, NOD1, CXCL8, and IRF1 expression levels were also significantly upregulated in gastric tumor tissues, when compared with paired nontumor samples (p < 0.0001, p < 0.05, and p < 0.05, respectively). Thus, we propose that cross-talk between NOD1 and IFN-γ signaling pathways contribute to H. pylori–induced inflammatory responses, potentially revealing a novel mechanism whereby virulent H. pylori strains promote more severe disease.

Novel population-based study finding higher than reported hepatocellular carcinoma incidence suggests an updated approach is needed

Hepatocellular carcinoma (HCC) incidence is rising rapidly in many developed countries. Primary epidemiological data have invariably been derived from cancer registries that are heterogeneous in data quality and registration methodology; many registries have not adopted current clinical diagnostic criteria for HCC and still rely on histology for classification. We performed the first population‐based study in Australia using current diagnostic criteria, hypothesizing that HCC incidence may be higher than reported. Incident cases of HCC (defined by American Association for the Study of Liver Diseases diagnostic criteria or histology) were prospectively identified over a 12‐month period (2012‐2013) from the population of Melbourne, Australia. Cases were captured from multiple sources: admissions to any of Melbournes seven tertiary hospitals; attendances at outpatients; and radiology, pathology, and pharmacy services. Our cohort was compared to the Victorian Cancer Registry (VCR) cohort (mandatory notified cases) for the same population and period, and incidence rates were compared for both cohorts. There were 272 incident cases (79% male; median age: 65 years) identified. Cirrhosis was present in 83% of patients, with hepatitis C virus infection (41%), alcohol (39%), and hepatitis B virus infection (22%) the commonest etiologies present. Age‐standardized HCC incidence (per 100,000, Australian Standard Population) was 10.3 (95% confidence interval [CI]: 9.0‐11.7) for males and 2.3 (95% CI: 1.8 to 3.0) for females. The VCR reported significantly lower rates of HCC: 5.3 (95% CI: 4.4 to 6.4) and 1.0 (95% CI: 0.7 to 1.5) per 100,000 males and females respectively (P < 0.0001). Conclusions: HCC incidence in Melbourne is 2‐fold higher than reported by cancer registry data owing to under‐reporting of clinical diagnoses. Adoption of current diagnostic criteria and additional capture sources will improve registry completeness. Chronic viral hepatitis and alcohol remain leading causes of cirrhosis and HCC. (Hepatology 2016;63:1205–1212)

The molecular pathogenesis of STAT3-driven gastric tumourigenesis in mice is independent of IL-17

Chronic activation of the gastric mucosal adaptive immune response is a characteristic trait of gastric cancer. It has recently emerged that a new class of T helper (Th) cells, defined by their ability to produce interleukin (IL)‐17A (Th17), is associated with a host of inflammatory responses, including gastritis. However, the role of these Th17 cells in the pathogenesis of gastric cancer is less clear. To formally address this, we employed gp130F/F mice, which spontaneously develop gastric inflammation‐associated tumours akin to human intestinal‐type gastric cancer. At the molecular level, these tumours demonstrate hyper‐activation of the latent transcription factor signal transducer and activator of transcription (STAT)3 via the IL‐6 cytokine family member, IL‐11. In gp130F/F mice, the generation of Th17 cells, as well as the gastric expression of IL‐17a and other Th17‐related factors (Rorγt, IL‐23), were augmented compared to wild‐type gp130+/+ mice. Consistent with a role for IL‐6 and STAT3 in regulating IL‐17A, increased Th17 generation and gastric expression of Th17‐related factors in gp130F/F mice were reduced to wild‐type levels in gp130F/F:Stat3−/+ mice displaying normalized STAT3 activity, and also in gp130F/F:IL‐6−/− mice. Importantly, genetic ablation of IL‐17A in gp130F/F:IL‐17a−/− mice did not suppress the initiation and growth of gastric tumours. Furthermore, IL‐17A and RORC gene expression was strongly increased in human gastric biopsies from patients with gastritis, but not gastric cancer. Collectively, our data suggest that increased expression of Th17‐related factors does not correlate with the molecular pathogenesis of gastric tumourigenesis. # Copyright

Efficacy and tolerability of pegylated interferon-α-2a in chronic hepatitis B: A multicenter clinical experience

Background and Aim:  Pegylated interferon‐α (PEG‐IFN) provides potential advantages over nucleos(t)ide analogues in the treatment of chronic hepatitis B (CHB) given its finite course, durability and lack of drug resistance. Much of the evidence is derived from controlled studies and it is unclear whether these results can be replicated in an everyday, non‐controlled setting. The aim of this study was to examine the efficacy and tolerability of PEG‐IFN‐α2A in CHB patients in a clinical setting.