The publication data currently available has been vetted by Vanderbilt faculty, staff, administrators and trainees. The data itself is retrieved directly from NCBI's PubMed and is automatically updated on a weekly basis to ensure accuracy and completeness.
If you have any questions or comments, please contact us.
Individuals with sporadic colorectal cancer (CRC) frequently harbor abnormalities in the composition of the gut microbiome; however, the microbiota associated with precancerous lesions in hereditary CRC remains largely unknown. We studied colonic mucosa of patients with familial adenomatous polyposis (FAP), who develop benign precursor lesions (polyps) early in life. We identified patchy bacterial biofilms composed predominately of and Genes for colibactin () and toxin (), encoding secreted oncotoxins, were highly enriched in FAP patients' colonic mucosa compared to healthy individuals. Tumor-prone mice cocolonized with (expressing colibactin), and enterotoxigenic showed increased interleukin-17 in the colon and DNA damage in colonic epithelium with faster tumor onset and greater mortality, compared to mice with either bacterial strain alone. These data suggest an unexpected link between early neoplasia of the colon and tumorigenic bacteria.
Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.
OBJECTIVE - To evaluate the long-term effect of cumulative time exposed to infection on the progression of gastric lesions.
DESIGN - 795 adults with precancerous gastric lesions were randomised to receive anti- treatment at baseline. Gastric biopsies were obtained at baseline and at 3, 6, 12 and 16 years. A total of 456 individuals attended the 16-year visit. Cumulative time of exposure was calculated as the number of years infected during follow-up. Multivariable logistic regression models were used to estimate the risk of progression to a more advanced diagnosis (versus no change/regression) as well as gastric cancer risk by intestinal metaplasia (IM) subtype. For a more detailed analysis of progression, we also used a histopathology score assessing both severity and extension of the gastric lesions (range 1-6). The score difference between baseline and 16 years was modelled by generalised linear models.
RESULTS - Individuals who were continuously infected with for 16 years had a higher probability of progression to a more advanced diagnosis than those who cleared the infection and remained negative after baseline (p=0.001). Incomplete-type IM was associated with higher risk of progression to cancer than complete-type (OR, 11.3; 95% CI 1.4 to 91.4). The average histopathology score increased by 0.20 units/year (95% CI 0.12 to 0.28) among individuals continuously infected with . The effect of cumulative time of infection on progression in the histopathology score was significantly higher for individuals with atrophy (without IM) than for individuals with IM (p<0.001).
CONCLUSIONS - Long-term exposure to infection was associated with progression of precancerous lesions. Individuals infected with with these lesions may benefit from eradication, particularly those with atrophic gastritis without IM. Incomplete-type IM may be a useful marker for the identification of individuals at higher risk for cancer.
© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.
Helicobacter pylori infection triggers a cascade of inflammatory stages that may lead to the appearance of non-atrophic gastritis, multifocal atrophic, intestinal metaplasia, dysplasia, and cancer. Deleted in malignant brain tumors 1 (DMBT1) belongs to the group of secreted scavenger receptor cysteine-rich proteins and is considered to be involved in host defense by binding to pathogens. Initial studies showed its deletion and loss of expression in a variety of tumors but the role of this gene in tumor development is not completely understood. Here, we examined the role of DMBT1 in gastric precancerous lesions in Caucasian, African American and Hispanic individuals as well as in the development of gastric pathology in a mouse model of H. pylori infection. We found that in 3 different populations, mucosal DMBT1 expression was significantly increased (2.5 fold) in individuals with dysplasia compared to multifocal atrophic gastritis without intestinal metaplasia; the increase was also observed in individuals with advanced gastritis and positive H. pylori infection. In our animal model, H. pylori infection of Dmbt1-/- mice resulted in significantly higher levels of gastritis, more extensive mucous metaplasia and reduced Il33 expression levels in the gastric mucosa compared to H. pylori-infected wild type mice. Our data in the animal model suggest that in response to H. pylori infection DMBT1 may mediate mucosal protection reducing the risk of developing gastric precancerous lesions. However, the increased expression in human gastric precancerous lesions points to a more complex role of DMBT1 in gastric carcinogenesis.
Dysregulation of the oncogenic transcription factor MYC induces B-cell transformation and is a driver for B-cell non-Hodgkin lymphoma (B-NHL). MYC overexpression in B-NHL is associated with more aggressive phenotypes and poor prognosis. Although genomic studies suggest a link between MYC overexpression and B-cell receptor (BCR) signaling molecules in B-NHL, signaling pathways essential to Myc-mediated B-cell transformation have not been fully elucidated. We utilized intracellular phospho-flow cytometry to investigate the relationship between Myc and BCR signaling in pre-malignant B cells. Utilizing the Eμ-myc mouse model, where Myc is overexpressed specifically in B cells, both basal and stimulated BCR signaling were increased in precancerous B lymphocytes from Eμ-myc mice compared with wild-type littermates. B cells overexpressing Myc displayed constitutively higher levels of activated CD79α, Btk, Plcγ2 and Erk1/2. Notably, Myc-overexpressing B cells maintained elevated BCR signaling despite treatment with ibrutinib, a Bruton's tyrosine kinase inhibitor. Furthermore, PI3K/Akt pathway signaling was also increased in Eμ-myc B cells, and this increase was partially suppressed with ibrutinib. In addition, experiments with Btk-null B cells revealed off-target effects of ibrutinib on BCR signaling. Our data show that in pre-malignant B cells, Myc overexpression is sufficient to activate BCR and PI3K/Akt signaling pathways and further enhances signaling following BCR ligation. Therefore, our results indicate that precancerous B cells have already acquired enhanced survival and growth capabilities before transformation, and that elevated MYC levels confer resistance to pharmacologic inhibitors of BCR signaling, which has significant implications for B-NHL treatment.
Epidermal growth factor receptor (EGFR) signaling is a known mediator of colorectal carcinogenesis. Studies have focused on the role of EGFR signaling in epithelial cells, although the exact nature of the role of EGFR in colorectal carcinogenesis remains a topic of debate. Here, we present evidence that EGFR signaling in myeloid cells, specifically macrophages, is critical for colon tumorigenesis in the azoxymethane-dextran sodium sulfate (AOM-DSS) model of colitis-associated carcinogenesis (CAC). In a human tissue microarray, colonic macrophages demonstrated robust EGFR activation in the pre-cancerous stages of colitis and dysplasia. Utilizing the AOM-DSS model, mice with a myeloid-specific deletion of Egfr had significantly decreased tumor multiplicity and burden, protection from high-grade dysplasia and significantly reduced colitis. Intriguingly, mice with gastrointestinal epithelial cell-specific Egfr deletion demonstrated no differences in tumorigenesis in the AOM-DSS model. The alterations in tumorigenesis in myeloid-specific Egfr knockout mice were accompanied by decreased macrophage, neutrophil and T-cell infiltration. Pro-tumorigenic M2 macrophage activation was diminished in myeloid-specific Egfr-deficient mice, as marked by decreased Arg1 and Il10 mRNA expression and decreased interleukin (IL)-4, IL10 and IL-13 protein levels. Surprisingly, diminished M1 macrophage activation was also detectable, as marked by significantly reduced Nos2 and Il1b mRNA levels and decreased interferon (IFN)-γ, tumor necrosis factor (TNF)-α and IL-1β protein levels. The alterations in M1 and M2 macrophage activation were confirmed in bone marrow-derived macrophages from mice with the myeloid-specific Egfr knockout. The combined effect of restrained M1 and M2 macrophage activation resulted in decreased production of pro-angiogenic factors, CXCL1 and vascular endothelial growth factor (VEGF), and reduced CD31 blood vessels, which likely contributed to protection from tumorigenesis. These data reveal that EGFR signaling in macrophages, but not in colonic epithelial cells, has a significant role in CAC. EGFR signaling in macrophages may prove to be an effective biomarker of CAC or target for chemoprevention in patients with inflammatory bowel disease.
Infection with Helicobacter pylori (H. pylori) leads to inflammatory events that can promote gastric cancer development. Immune cells transition from the circulation into the infected mucosa through the interaction of their receptors and ligands in the endothelial compartment. CD44 expression is increased in advanced gastric lesions. However, the association of this molecule with the progression of these lesions over time has not been investigated. In addition, there is a lack of understanding of the CD44-dependent cellular processes that lead to gastritis, and possibly to gastric cancer. Here we studied H. pylori-positive subjects with gastric lesions that ranged from multifocal atrophic gastritis to dysplasia to determine gene expression changes associated with disease progression over a period of 6 years. We report that CD44 expression is significantly increased in individuals whose gastric lesions progressed along the gastric precancerous cascade. We also show that CD44-/- mice develop less severe and less extensive H. pylori-induced metaplasia, and show fewer infiltrating Gr1+ cells compared to wild type mice. We present data suggesting that CD44 is associated with disease progression. Mechanisms associated with these effects include induction of interferon gamma responses.
Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
Colonization of the human stomach by Helicobacter pylori and its role in causing gastric cancer is one of the richest examples of a complex relationship among human cells, microbes, and their environment. It is also a puzzle of enormous medical importance given the incidence and lethality of gastric cancer worldwide. We review recent findings that have changed how we view these relationships and affected the direction of gastric cancer research. For example, recent data have indicated that subtle mismatches between host and microbe genetic traits greatly affect the risk of gastric cancer. The ability of H pylori and its oncoprotein CagA to reprogram epithelial cells and activate properties of stemness show the sophisticated relationship between H pylori and progenitor cells in the gastric mucosa. The observation that cell-associated H pylori can colonize the gastric glands and directly affect precursor and stem cells supports these observations. The ability to mimic these interactions in human gastric organoid cultures as well as animal models will allow investigators to more fully unravel the extent of H pylori control on the renewing gastric epithelium. Finally, our realization that external environmental factors, such as dietary components and essential micronutrients, as well as the gastrointestinal microbiota, can change the balance between H pylori's activity as a commensal or a pathogen has provided direction to studies aimed at defining the full carcinogenic potential of this organism.
Copyright © 2016. Published by Elsevier Inc.
BACKGROUND - Development of the intestinal subtype of gastric adenocarcinoma is marked by a progression of histopathologic lesions. Residents of the Andean regions of Colombia are at high risk for gastric cancer.
METHODS - A cohort of 976 Colombian subjects was followed over 16 years examining effects of Helicobacter pylori eradication and treatment with antioxidants on progression of lesions. We performed methylation analysis of DNA from baseline antral biopsies from 104 subjects for whom follow-up data were available for at least 12 years. Methylation was quantitated for AMPH, CDKN2A, CDH1, EN1, EMX1, NKX6-1, PCDH10, RPRM, RSPO2, SORCS3, ZIC1, and ZNF610 genes, using Pyrosequencing.
RESULTS - Levels of DNA methylation were associated with baseline diagnosis for AMPH, EMX1, RPRM, RSPO2, SORCS3, and ZNF610. After adjusting for baseline diagnosis and H. pylori infection, methylation levels of AMPH, PCDH10, RSPO2, and ZNF610 had progression coefficients that increased and P values that decreased over 6, 12, and 16 years. Methylation for SORCS3 was associated with progression at all 3 time points but without the continual strengthening of the effect. Scores for mononuclear leukocytes, polymorphonuclear leukocytes, or intraepithelial lymphocytes were unrelated to progression.
CONCLUSIONS - Methylation levels of AMPH, PCDH10, RSPO2, SORCS3, and ZNF610 predict progression of gastric lesions independent of the effect of duration of H. pylori infection, baseline diagnosis, gender of the patient, or scores for mononuclear leukocytes, polymorphonuclear leukocytes, or intraepithelial lymphocytes.
IMPACT - DNA methylation levels in AMPH, PCDH10, RSPO2, SORCS3, and ZNF610 may contribute to identification of persons with gastric lesions likely to progress.
©2015 American Association for Cancer Research.
BACKGROUND - Human papillomavirus (HPV) testing in urine offers a convenient approach for cervical cancer screening but has previously suffered from limited clinical sensitivity.
OBJECTIVES - We evaluated clinical performance of the prototype Trovagene HPV test, a novel polymerase chain reaction assay that targets the E1 region of the HPV genome and detects and amplifies short fragments of cell-free HPV DNA in urine.
STUDY DESIGN - We conducted a pilot study among 72 women referred to colposcopy following abnormal screening. Participants provided a urine sample prior to clinician-collected cervical sampling and colposcopically-directed punch biopsy. Trovagene HPV test results on urine samples were compared with cervical and urine testing by Linear Array HPV Genotyping Test (LA-HPV) for detection of histologically-confirmed cervical precancerous lesions.
RESULTS - There was high concordance between urine samples tested by the Trovagene HPV test and corresponding cervical (87.5%) and urine (81.9%) samples tested by LA-HPV. The Trovagene HPV test had high sensitivity (92.3% for detecting CIN2/3, and 100% for CIN3), comparable to LA-HPV testing on cervical samples (96.0% and 100%, respectively), and higher than LA-HPV testing on urine samples (80.8% and 90.0%, respectively). In this referral population, the specificity of the Trovagene urine HPV test was non-significantly lower (29% for CIN2/3 and 25% for CIN3) than corresponding estimates of LA-HPV testing on cervical (36% and 28%, respectively) and urine (42% and 38%, respectively) samples.
CONCLUSIONS - This pilot study suggests that the Trovagene HPV test has high sensitivity for urine-based detection of cervical precancer and merits evaluation in larger studies.
Published by Elsevier B.V.
Helicobacter pylori is the strongest risk factor for the development of gastric cancer. Although the specific mechanisms by which this pathogen induces carcinogenesis have not been fully elucidated, high-expression interleukin (IL)-1β alleles are associated with increased gastric cancer risk among H. pylori-infected persons. In addition, loss of matrix metalloproteinase 7 (MMP7) increases mucosal inflammation in mouse models of epithelial injury, and we have shown that gastric inflammation is increased in H. pylori-infected MMP7(-/-) C57BL/6 mice. In this report, we define mechanisms that underpin such responses and extend these results into a genetic model of MMP7 deficiency and gastric cancer. Wild-type (WT) or MMP7(-/-) C57BL/6 mice were challenged with broth alone as an uninfected control or the H. pylori strain PMSS1. All H. pylori-challenged mice were successfully colonized. As expected, H. pylori-infected MMP7(-/-) C57BL/6 mice exhibited a significant increase in gastric inflammation compared with uninfected or infected WT C57BL/6 animals. Loss of MMP7 resulted in M1 macrophage polarization within H. pylori-infected stomachs, as assessed by Luminex technology and immunohistochemistry, and macrophages isolated from infected MMP7-deficient mice expressed significantly higher levels of the M1 macrophage marker IL-1β compared with macrophages isolated from WT mice. To extend these findings into a model of gastric cancer, hypergastrinemic WT INS-GAS or MMP7(-/-) INS-GAS mice were challenged with H. pylori strain PMSS1. Consistent with findings in the C57BL/6 model, H. pylori-infected MMP7-deficient INS-GAS mice exhibited a significant increase in gastric inflammation compared with either uninfected or infected WT INS-GAS mice. In addition, the incidence of gastric hyperplasia and dysplasia was significantly increased in H. pylori-infected MMP7(-/-) INS-GAS mice compared with infected WT INS-GAS mice, and loss of MMP7 promoted M1 macrophage polarization. These results suggest that MMP7 exerts a restrictive role on H. pylori-induced gastric injury and the development of premalignant lesions by suppressing M1 macrophage polarization.