Cellular origin of gastric cancer

Simulation of Swanson's literature-based discovery: anandamide treatment inhibits growth of gastric cancer cells in vitro and in silico

Swanson's literature-based discovery focus on resurrecting previously published but neglected knowledge. In this study, we propose a two-step model of the discovery process and generate a hypothesis between anandamide and gastric cancer. Further, the potential relationship was confirmed by follow-up experimentation. The anandamide treatment resulted in cell cycle redistribution of gastric cancer cells. Most importantly, the variation of cell cycle was mediated by some genes from the B-terms of the closed discovery, indicating the potential role of the B-terms. Swanson's literature-based discovery not only collates data for possible interactions, but also provides the potential to observe the larger background behind these direct links and is an invaluable discovery tool for investigators.

Helicobacter pylori CagA: From Pathogenic Mechanisms to Its Use as an Anti-Cancer Vaccine

Helicobacter pylori colonizes the gastric mucosa of more than 50% of the human population, causing chronic inflammation, which however is largely asymptomatic. Nevertheless, H. pylori-infected subjects can develop chronic gastritis, peptic ulcer, gastric mucosa-associated lymphoid tissue lymphoma, and gastric cancer. Chronic exposure to the pathogen and its ability to induce epithelial to mesenchymal transition (EMT) through the injection of cytotoxin-associated gene A into gastric epithelial cells may be key triggers of carcinogenesis. By deregulating cell-cell and cell-matrix interactions as well as DNA methylation, histone modifications, expression of micro RNAs, and resistance to apoptosis, EMT can actively contribute to early stages of the cancer formation. Host response to the infection significantly contributes to disease development and the concomitance of particular genotypes of both pathogen and host may turn into the most severe outcomes. T regulatory cells (Treg) have been recently demonstrated to play an important role in H. pylori-related disease development and at the same time the Treg-induced tolerance has been proposed as a possible mechanism that leads to less severe disease. Efficacy of antibiotic therapies of H. pylori infection has significantly dropped. Unfortunately, no vaccine against H. pylori is currently licensed, and protective immunity mechanisms against H. pylori are only partially understood. In spite of promising results obtained in animal models of infection with a number of vaccine candidates, few clinical trials have been conducted so far and with no satisfactory outcomes. However, prophylactic vaccination may be the only means to efficiently prevent H. pylori-associated cancers.

Far upstream element-binding protein 1 (FUBP1) is overexpressed in human gastric cancer tissue compared to non-cancerous tissue

BACKGROUND

The aim of this study was to investigate the role of far upstream element-binding protein 1 (FUBP1) in gastric cancer development.

PATIENTS AND METHODS

Using immunohistochemistry, we detected FUBP1 expression in 18 chronic superficial gastritis patients, 33 chronic atrophic gastritis patients, 21 moderate and severe gastric dysplasia patients, and 31 gastric cancer patients. FUBP1 mRNA expression in gastric cancer tissue and paraneoplastic tissue was measured with fluorescent quantitative reverse transcription polymerase chain reaction.

RESULTS

The FUBP1 expression rates in the chronic atrophic gastritis, moderate and severe dysplasia, and gastric cancer patients were 51.51% (17/33), 76.19% (16/21), and 90.32% (28/31), respectively; these were higher than the expression rate of the chronic superficial gastritis patients (11.11%, 2/18). FUBP1 expression in the gastric cancer patients was significantly higher than that in the chronic atrophic gastritis patients. The relative amount (0.2593 ± 0.1209) of FUBP1 mRNA in the gastric cancer tissue was higher than that in paraneoplastic tissue (0.1969 ± 0.0211) (p < 0.05). There was a statistically significant correlation between overall survival rates and age, sex, lymph node metastasis, and distant metastasis (p < 0.05).

CONCLUSION

FUBP1 expression differs among gastric tissues. There is a correlation between overall survival rates and age, sex, lymph node metastasis, and distant metastasis.

Gastric cancer stem cells: a novel therapeutic target

Gastric cancer remains one of the leading causes of global cancer mortality. Multipotent gastric stem cells have been identified in both mouse and human stomachs, and they play an essential role in the self-renewal and homeostasis of gastric mucosa. There are several environmental and genetic factors known to promote gastric cancer. In recent years, numerous in vitro and in vivo studies suggest that gastric cancer may originate from normal stem cells or bone marrow-derived mesenchymal cells, and that gastric tumors contain cancer stem cells. Cancer stem cells are believed to share a common microenvironment with normal niche, which play an important role in gastric cancer and tumor growth. This mini-review presents a brief overview of the recent developments in gastric cancer stem cell research. The knowledge gained by studying cancer stem cells in gastric mucosa will support the development of novel therapeutic strategies for gastric cancer.

Precancerous lesions in the stomach: from biology to clinical patient management

Gastric cancer is the final step in a multi-stage cascade triggered by long-standing inflammatory conditions (particularly Helicobacter pylori infection) resulting in atrophic gastritis and intestinal metaplasia: these lesions represent the cancerization field in which (intestinal-type) gastric cancer develops. Intraepithelial neoplasia is consistently recognized as the phenotypic bridge between atrophic/metaplastic lesions and invasive cancer. This paper addresses the epidemiology, pathology, molecular profiling, and clinical management of advanced precancerous gastric lesions.

Helicobacter pylori infection induced gastric cancer; advance in gastric stem cell research and the remaining challenges

Helicobacter pylori infection is the major cause of gastric cancer, which remains an important health care challenge. Recent investigation in gastric stem cell or progenitor cell biology has uncovered valuable information in understanding the gastric gland renewal and maintenance of homeostasis, they also provide clues for further defining the mechanisms by which gastric cancer may originate and progress. Lgr5, Villin-promoter, TFF2-mRNA and Mist have recently been identified as gastric stem/progenitor cell markers; their identification enriched our understanding on the gastric stem cell pathobiology during chronic inflammation and metaplasia. In addition, advance in gastric cancer stem cell markers such as CD44, CD90, CD133, Musashi-1 reveal novel information on tumor cell behavior and disease progression implicated for therapeutics. However, two critical questions remain to be of considerable challenges for future exploration; one is how H. pylori or chronic inflammation affects gastric stem cell or their progenitors, which give rise to mucus-, acid-, pepsinogen-, and hormone-secreting cell lineages. Another one is how bacterial infection or inflammation induces oncogenic transformation and propagates into tumors. Focus on the interactions of H. pylori with gastric stem/progenitor cells and their microenvironment will be instrumental to decipher the initiation and origin of gastric cancer. Future studies in these areas will be critical to uncover molecular mechanisms of chronic inflammation-mediated oncogenic transformation and provide options for cancer prevention and intervention. We review recent progress and discuss future research directions in these important research fields.

Influence of behavior factors on the development, prevention and management of gastric cancer

Gastric cancer is the fourth most common malignancy worldwide and is globally the second leading cause of cancer-related deaths each year. Among the risk factors are genetic factors, environmental factors and other factors. Helicobacter pylori (H. pylori) has been found to be the major carcinogen in gastric cancer development. Approximately 65%-80% of non-cardia gastric adenocarcinoma is attributable to H. pylori infection. One percent of patients infected with H. pylori will develop gastric cancer. American and European guidelines on the management of H. pylori infection recommend H. pylori eradication in all patients with atrophy and/or intestinal metaplasia. In the Asian Pacific Gastric Cancer Consensus, it was suggested for the first time that it is time for population-based screening and treatment of H. pylori infection in regions where gastric cancer incidence is above 20/100 000 per year. Although the incidence of gastric cancer is declining, its mortality rate is high. Many risk factors have been confirmed and have taken basic precautions. H. pylori eradication treatment reduced but did not completely eliminate the risk factors for gastric cancer. With further research, the role of behavioral factors in the development of gastric cancer has become increasingly prominent. Elucidation of the role of behavioral factors in the development of gastric cancer can help us better prevent and manage this disease.

Gastric cancer, Helicobacter pylori infection and other risk factors

Gastric cancer incidence is declining. However, it is too early to consider this neoplastic disease as rare and the worldwide mortality rate still remains high. Several risk factors have been identified for non-cardia gastric cancer and primary prevention is feasible since most of the risk factors can be removed. Helicobacter pylori eradication treatment reduces but does not abolish gastric cancer risk. Indeed, gastric cancer is a multifactorial disease and removing one factor does not therefore prevent all cases. Endoscopic surveillance is still needed, especially in subjects at higher risk. The definition of high-risk patients will be the future challenge as well as identifying the best surveillance strategy for such patients.

Helicobacter pylori infection, oncogenic pathways and epigenetic mechanisms in gastric carcinogenesis

Chronic colonization of the human stomach by Helicobacter pylori, a Gram-negative bacterium, is the major cause of chronic gastritis, peptic ulcers and gastric cancer. Recent progress has elucidated important bacterial and host factors that are responsible for H. pylori-induced gastric inflammation and gastric malignancy. H. pylori cytotoxin-associated antigen A is the major oncogenic factor injected into host cells from bacteria and it disrupts epithelial cell functions. Together with H. pylori cag pathogenicity island, it causes general inflammatory stress within gastric mucosa and activates multiple oncogenic pathways in epithelial cells. A growing list of these pathways includes NF-kappaB, activator protein-1, PI3K, signal transducers and activators of transcription 3, Wnt/beta-catenin and cyclooxygenase 2. H. pylori induces epigenetic alterations, such as DNA methylation and histone modification, which play critical roles in oncogenic transformation. In addition, investigations into gastric stem cell or progenitor cell biology have shed light on the mechanisms through which gastric cancer may originate. Continued investigation in these areas will yield novel insights and help to elucidate the mechanisms of bacteria-induced carcinogenesis.

Upper gastrointestinal carcinogenesis: H. pylori and stem cell cross-talk

Chronic inflammation of the gastric epithelium has been associated with the pathogenesis of gastric cancer, as it was postulated by Corea's model of gastric carcinogenesis. Helicobacter pylori (Hp) regulates this inflammatory process and promotes gastric carcinogenesis through induction of gene mutations and protein modulation. Recent data raise the cancer stem cell hypothesis, which implies a central role of multipotent cancer cells in oncogenesis of various solid tumors. This review provides a synopsis of gastric cancer initiation and promotion through Hp and stem cell signaling pathways. The expanding research field of Hp-related cancer stem cell biology may offer novel implications for future treatment of upper gastrointestinal cancer.

Molecular Genetics of Gastric Adenocarcinoma

Gastric carcinoma is the second leading cause of cancer deaths in the world. Its aetiology is closely linked to the bacterial pathogen Helicobacter pylori which is believed to induce a state of chronic inflammation that predisposes to a cascade of molecular and cellular alterations leading to carcinogenesis. Although the exact process of gastric carcinogenesis has yet to be elucidated fully, the interaction of the genetic factors with environmental factors is likely to be a significant consideration. Numerous genes and molecular pathways have been discovered to be associated with gastric adenocarcinoma and more importantly, it is now becoming possible to use some of these as means of prognostication and targeted therapy. This review will outline our current understanding of the aetiology and molecular genetics of gastric adenocarcinoma and its current clinical applications.

Diet synergistically affects helicobacter pylori-induced gastric carcinogenesis in nonhuman primates

BACKGROUND & AIMS

Gastric cancer results from a combination of Helicobacter pylori (H pylori) infection, exposure to dietary carcinogens, and predisposing genetic make-up. Because the role of these factors in gastric carcinogenesis cannot be determined readily in human beings, the present study examined the role of an oral carcinogen and H pylori infection in rhesus monkeys.

METHODS

Gastroscopies were performed in 23 monkeys assigned to 4 groups: controls; nitrosating carcinogen ethyl-nitro-nitrosoguanidine administration alone; inoculation of a virulent H pylori strain alone (H); and ethyl-nitro-nitrosoguanidine in combination with H pylori (EH). Follow-up gastroscopies and biopsies were performed at 3-month intervals for 5 years for pathologic and molecular studies.

RESULTS

Postinoculation, H and EH groups showed persistent infection and antral gastritis. Starting at 2 and 5 years, respectively, gastric intestinal metaplasia and intraepithelial neoplasia developed in 3 EH monkeys but in no other groups. Transcriptional analysis of biopsy specimens at 5 years revealed group-specific expression profiles, with striking changes in EH monkeys, plus a neoplasia-specific expression profile characterized by changes in multiple cancer-associated genes. Importantly, this neoplastic profile was evident in nonneoplastic mucosa, suggesting that the identified genes may represent markers preceding cancer.

CONCLUSIONS

Gastric intraglandular neoplasia is induced in primates when H pylori infection is associated with consumption of a carcinogen similar to the nitrosamines found in pickled vegetables, suggesting that H pylori and the carcinogen synergistically induce gastric neoplasia in primates.