Recent knowledge of the relationship between Helicobacter pylori and gastric cancer and recent progress of gastroendoscopic diagnosis and treatment for gastric cancer

Study on the correlation between Helicobacter Pylori and biological characteristics of early Gastric Cancer

Objective: Retrospective analysis was used to determine the population diagnosed with EGC, and HP infection was used as the cut-off point to further evaluate the correlation between helicobacter pylori (HP) infection and tumor biological characteristics of early gastric cancer (EGC). Methods: All cases were collected from patients diagnosed with EGC through endoscopic surgery or surgical procedures from January 2009 to October 2018. General information, tumor site, tumor pathology, HER2 immunohistochemical results, and degree of HP infection were collected for retrospective analysis. Results: A total of 111 cases were collected in this study. Among the HP negative group, there were statistically significant differences in tumor sites between the uninfected group and the previously infected group (P<0.05).There were significant differences in monocyte infiltration and neutrophil infiltration between the positive and negative groups (P<0.05).The differentiated adenocarcinoma in the positive group was significantly lower than that in the negative group. The incidence rate of Mixed type cancer was significantly higher than that in the positive group (P<0.01). In the positive group of HP, there was a statistically significant difference in HER2 between the unsterilized group and the previously sterilized group (P<0.05).There was a statistically significant difference in HER2 between the HP positive group and the HP negative group (P<0.01). HP infection was significantly correlated with HER2 index and presented a positive correlation (P=0.014). Conclusion: HP infection is related to the tumor site and mucosal inflammatory infiltration of EGC. The malignant degree of EGC complicated with HP infection is higher, and most of them are mixed type. The degree of HP infection was positively correlated with the degree of invasion and malignancy of ECG. Furthermore, the tumor indicator HER2 is closely related to HP infection, and the detection of HP combined with HER2 is of great significance in the discovery of EGC and the evaluation of its malignancy.

Antiproliferative Benzoindazolequinones as Potential Cyclooxygenase-2 Inhibitors

Quinones and nitrogen heterocyclic moieties have been recognized as important pharmacophores in the development of antitumor agents. This study aimed to establish whether there was any correlation between the in silico predicted parameters and the in vitro antiproliferative activity of a family of benzoindazolequinones (BIZQs), and to evaluate overexpressed proteins in human cancer cells as potential biomolecular targets of these compounds. For this purpose, this study was carried out using KATO-III and MCF-7 cell lines as in vitro models. Docking results showed that these BIZQs present better binding energies (ΔG_bin) values for cyclooxygenase-2 (COX-2) than for other cancer-related proteins. The predicted ∆G_bin values of these BIZQs, classified in three series, positively correlated with IC₅₀ measured in both cell lines (KATO-III: 0.72, 0.41, and 0.90; MCF-7: 0.79, 0.55, and 0.87 for Series I, II, and III, respectively). The results also indicated that compounds 2a, 2c, 6g, and 6k are the most prominent BIZQs, because they showed better IC₅₀ and ∆G_bin values than the other derivatives. In silico drug absorption, distribution, metabolism, and excretion (ADME) properties of the three series were also analyzed and showed that several BIZQs could be selected as potential candidates for cancer pre-clinical assays.

Association of host immunity with Helicobacter pylori infection in recurrent gastric cancer

Background

Helicobacter pylori infection is associated with the incidence of gastric cancer. Endoscopic resection has been developed as a proper technique to treat early stage of gastric cancer. However, some patients develop recurrent gastric cancer within 5 years after endoscopic treatment. The aim of the present study is to explore a biomarker for detecting people who has high risk of gastric cancer recurrence.

Methods

We analyzed the Interleukin-10 (IL-10) single nucleotide polymorphism (SNP) and IgG subclass responses to the bacteria in patients with early gastric cancer and recurrent gastric cancer.

Results

Patients with hetero-type in the 1082 SNP and CC genotype in the 592 SNP were at high risk of recurrence of gastric cancer. In patients with genotype carrying high risk of recurrence, IgG1 level tended to be higher than that in patients with other genotypes.

Conclusions

Dominance of T helper 2 (Th2) immunity controlled by IL-10 cytokine may be associated with H. pylori-associated gastric cancer recurrence.

Helicobacter pylori Infection in Children and Adolescents

About one-third of all children worldwide is infected with H. pylori and its prevalence is low in developed and high in developing countries. H. pylori is mainly acquired during childhood and transmission of the bacterium commonly proceeds from person to person, especially among family members. The most frequent transmission route is from the mother to children. Various gastrointestinal and extra-gastrointestinal diseases are reported to be associated with H. pylori in children and adolescents, but the strongest recommendation for testing and treating is introduced only with children and adolescents having peptic ulcer disease. Iron deficiency anemia and chronic immune thrombocytopenic purpura are also considered for testing and treating, but the effectiveness is somewhat controversial. Invasive diagnosis is recommended, whereas none of the available diagnostic tests have 100% accuracy for reliable diagnosis, and therefore at least two or more tests should be performed. Urea breath test is the most reliable among the non-invasive tests. Because the number of antibiotics-resistant H. pylori strains is increasing, it is desirable to conduct a drug susceptibility test before treatment and to select the corresponding regime. H. pylori has been proven to be a major cause of gastric cancer and 'screen-and-treat' strategies are recommended in communities at high risk of gastric cancer. However, the application to children and adolescents is controversial. An effective vaccine is desirable, but not yet available. Screen-and-treat for adolescents has started in a few areas in Japan, where conditions are well established. New prevention strategies for gastric cancer are awaited worldwide.

Effects of taxol resistance gene 1 on the cisplatin response in gastric cancer

Cisplatin is used to treat multiple types of solid tumor, including gastric cancer. Although cisplatin initially exhibits good efficacy, therapeutic failure often occurs owing to the development of chemoresistance. To the best of our knowledge, the underlying mechanism of cisplatin resistance remains unknown. The aim of the present study was to assess whether taxol resistance gene 1 (TXR1) has a role in cisplatin response in gastric cancer. The expression of TXR1 in fresh-frozen tissues of patients with gastric cancer who were sensitive or resistance to cisplatin was assessed. The level of TXR1 expression was significantly higher in cisplatin-resistant specimens than that in cisplatin-sensitive specimens. Next, the gastric cancer SGC-7901 cell line was exposed to cisplatin to establish a cisplatin-resistance subline, termed SGC-7901/DDP, which exhibited a 6-fold increases in the level of resistance. TXR1 expression was elevated in SGC-7901/DDP cells. Overexpression of TXR1 induced cisplatin resistance in SGC-7901 cells. Downregulation of TXR1 reversed the drug resistance caused by elevation of TXR1 expression in SGC-7901/DDP cells. Animal experiments proved the effect of TXR1 in inducing cisplatin resistance in vivo. Further investigation revealed that TXR1 regulated cisplatin resistance via apoptosis. In conclusion, TXR1 is worthy of further in-depth study as a potential therapeutic target in patients with gastric cancer.

MiR-122-5p inhibits cell migration and invasion in gastric cancer by down-regulating DUSP4

OBJECTIVE

To explore the relationship between miR-122-5p and DUSP4 and their effects on gastric cancer (GC) cell mobility and invasiveness.

METHODS

Abnormally expressed miRNAs and mRNAs were analyzed using microarrays. The miR-122-5p and DUSP4 mRNA expression levels in GC tissues and cells were determined by RT-qPCR. The target relationship between miR-122-5p and DUSP4 was validated by dual luciferase reporter assay. GC cell mobility and invasiveness were respectively observed by wound healing assay and transwell invasion assay. Western blot and immunohistochemistry were used for detection of the expressions of DUSP4 protein and MMP2 and MMP9 proteins related to cell invasion and migration. The migration and invasion abilities of gastric cancer cells in vivo were evaluated according to the number of lung metastatic nodules in mice.

RESULTS

The expression of miR-122-5p in GC tissues and cells was significantly down-regulated, whereas DUSP4 expression was up-regulated. Bioinformatics prediction strategies and dual luciferase reporter assay verified the binding sites of miR-122-5p on 3'UTR of DUSP4 and the target relationship between miR-122-5p and DUSP4. Overexpression of miR-122-5p and knockdown of DUSP4 in BGC-823 cells observantly suppressed GC cell mobility and invasiveness, whereas downregulation of miR-122-5p expression promoted cell metastasis. MiR-122-5p inhibited GC cell mobility and invasiveness and pulmonary tumor metastasis via downregulation of DUSP4.

CONCLUSION

MiR-122-5p restrained migration and invasion abilities of GC cells by repressing DUSP4.

MicroRNA-28 promotes cell proliferation and invasion in gastric cancer via the PTEN/PI3K/AKT signalling pathway

Gastric cancer is the fourth most common malignant disease and second leading cause of cancer‑associated mortalities worldwide. Previous studies revealed aberrantly expressed microRNAs (miRNAs) in various types of human cancer; these miRNAs play important roles in tumourigenesis and tumour development. miRNAs present a considerable potential for novel therapeutic approaches for treating human cancer. Therefore, the investigation of novel miRNAs involved in gastric cancer progression provides an opportunity to improve the prognosis of patients with gastric cancer. miRNA‑28 (miR‑28) has been investigated with regards to its expression and biological functions in many types of human cancer. However, previous studies have not discussed the expression patterns, roles and associated molecular mechanisms of miR‑28 in gastric cancer. In the present study, miR‑28 expression was identified to be upregulated in gastric cancer tissues and cell lines. miR‑28 inhibition functionally inhibited cell proliferation and invasion in gastric cancer in vitro. Using bioinformatics analysis, luciferase reporter assay, reverse transcription‑quantitative polymerase chain reaction and western blot analysis, phosphatase and tensin homolog (PTEN) was mechanically identified as a direct target of miR‑28 in gastric cancer. PTEN was downregulated in gastric cancer and negatively correlated with miR‑28 levels. Inhibition of PTEN restored the biological effects of miR‑28 downregulation on the proliferation and invasion of gastric cancer cells. Notably, the downregulation of miR‑28 results in the regulation of the phosphatidylinositol 3‑kinase/protein kinase B signaling pathway in gastric cancer. These results suggested that miR‑28 may be targeted for the development of novel treatments for gastric cancer in the future.

MicroRNA-197 inhibits gastric cancer progression by directly targeting metadherin

Gastric cancer is the fifth most frequent malignancy and the fourth most common cause of cancer‑associated mortality worldwide. MicroRNAs (miRNAs) are a group of small RNAs that regulate several cellular processes. In particular, a large number of miRNAs are involved in gastric cancer formation and progression. Thus, miRNAs may be considered as effective diagnostic biomarkers and therapeutic methods for gastric cancer. The aim of the current study was to detect miRNA (miR)‑197 expression in gastric cancer and to investigate its biological role and associated mechanism in gastric cancer. In the present study, miR‑197 expression was demonstrated to be considerably downregulated in gastric cancer tissues and cell lines. Its low expression level was associated with tumour size, invasive depth, tumour‑node‑metastasis staging and lymph node metastasis. High expression of miR‑197 inhibited tumour cell proliferation and invasion in vitro. Subsequently, metadherin (MTDH) was identified as a direct target gene of miR‑197 in gastric cancer, and this was confirmed by bioinformatics analysis, Dual‑luciferase reporter assay, reverse transcription quantitative polymerase chain reaction and western blot analysis. MTDH expression was upregulated in gastric cancer and was inversely correlated with miR‑197 expression levels. In addition, MTDH overexpression prevented the proliferation and inhibited invasion induced by miR‑197 overexpression. In addition, miR‑197 was demonstrated to regulate the phosphatase and tensin homolog (PTEN)/AKT signalling pathway in gastric cancer. The results of the present study suggested that miR‑197 serves a tumour‑suppressing role in human gastric carcinogenesis and progression by regulating the MTDH/PTEN/AKT signalling pathway. The miR‑197/MTDH axis may provide a novel effective therapeutic target for patients with gastric cancer.

Reduction of miR‑132‑3p contributes to gastric cancer proliferation by targeting MUC13

Abnormal expression of epidermal growth factor receptor (EGFR) signaling and microRNAs (miRNAs) has been widely seen in gastric cancer. The present study focused on the miRNAs that regulate human epidermal growth factor receptor (HER) activation through mucin 13 (MUC13). The protein level of MUC13 was demonstrated to be significantly increased in gastric cancer tissues compared with normal tissues by western blot analysis and immunohistochemistry. TargetScan bioinformatic predictions indicated that miRNA (miR)-212-3p and miR-132-3p may bind to the 3′-untranslated region of MUC13. Further investigation revealed that miR-132-3p was significantly decreased in gastric cancer tissues compared with normal tissues, whereas miR-212-3p expression was unaffected. Luciferase assays and western blot confirmed MUC13 as a target gene of miR-132-3p. Inhibition of miR-132-3p enhanced gastric cancer cell migration through activation of HER2, extracellular signal-regulated kinase (ERK) and Akt serine/threonine kinase (Akt) signaling, which was a similar effect to that of MUC13 overexpression. In summary, reduction of miR-132-3p may contribute to gastric cancer proliferation by targeting MUC13.

Gastric cancer burden of last 40 years in North China (Hebei Province): A population-based study

Gastric cancer (GC) is the second leading cause of cancer death in China. It is well known that Cixian in Hebei Province is one of the highest risk areas of GC in China and worldwide. This study aims to accurate assessment of GC burden and trend in high-risk area (Hebei Province) from 1973 to 2013. The authors analyzed GC data from 21 population-based cancer registries which represented 15.25% of the entire population of Hebei Province. The collected data were stratified by 5-year age groups, gender, and area. Mortality of GC was extracted from national death surveys from 1973 to 1975, 1990 to 1992, 2004 to 2005, and 2011 to 2013. Trend analysis (1988-2013) in a high-risk area (Cixian) used the Joinpoint Model. The age-period-cohort model was used to estimate the effects of age, period, and birth cohort in GC incidence in Cixian from 1988 to 2013. The crude incidence of GC in 2011 to 2013 was 40.37/100,000 (57.53/100,000 in males and 22.55/100,000 in females). The corresponding age-standardized rate by world age-standard population was 32.18/100,000 (48.87/100,000 in males and 17.53/100,000 in females), which was 2.66-fold (2.81-fold in male and 2.34-fold in female) higher than that in the world (12.1/100,000, 17.4/100,000 in males and 7.5/100,000 in females). Males in rural areas had the highest incidence, with an age-standardized rate of 70.51/100,000. Gastric cardia cancer was primary anatomical subsite which accounting for 59.59% in GC, followed by gastric corpus (13.92%), gastric antrum (11.43%), gastric fundus (4.99%), and overlapping lesion of gastric (4.17%). The age-standardized rate of mortality from GC displayed a significant downward trend (P = 0.019) in Hebei Province from the 1990s (31.44/100,000) to the 2010s (24.63/100,000). In Cixian, the incidence of GC rose from 1988 (38.25/100,000) to 2009 (65.11/100,000). Cixian, where population-based screening of upper gastrointestinal cancer was performed, experienced the increasing rate of GC from 2000 (37.59/100,000) to 2009 (65.11/100,000) and then had a sharp decrease from 2009 to 2013 (55.30/100,000), with annual percentage change of -6.69%. Gastric cardia cancer had an increasing trend from 1988 (6.88/100,000) to 2013 (26.56/100,000). Both age and birth cohort effects played important roles in these changes. In conclusion, males in rural areas had the highest risk of GC. GC mortality rate decreased from the 1990s in Hebei Province. Endoscopic screening project for GC is an effective method of controlling the disease.

Association between the expression of T-cadherin and vascular endothelial growth factor and the prognosis of patients with gastric cancer

T-cadherin has been identified as a tumor-suppressor gene in several types of cancer. The present study aimed to investigate the association of the expression of T-cadherin with angiogenesis, and to evaluate its prognostic value for patients with primary gastric cancer. Gastric cancer tissues and matched adjacent tissues from 166 patients receiving surgical resection were included in the present study. The expression of T-cadherin was detected using immunohistochemistry, western blotting and reverse transcription-quantitative polymerase chain reaction. The expression of vascular epidermal growth factor (VEGF) was detected using immunohistochemistry, and its association with the expression of T-cadherin was analyzed. In addition, the association between the expression of T-cadherin and clinicopathological features were analyzed. The mRNA and protein expression levels of T-cadherin were significantly lower in the gastric cancer tissue compared with the corresponding adjacent normal tissue (P<0.05). The expression of VEGF was not associated with the expression of T-cadherin in the gastric cancer tissue. The decreased protein expression of T-cadherin correlated with smoking, larger tumor size (diameter, >4 cm), lymph node metastasis and a higher tumor-lymph node-metastasis stage (P<0.05 or P<0.01). However, the expression of T-cadherin was not correlated with gender, age, alcohol intake, Helecobacter pylori infection or differentiation (P>0.05). The multivariate analysis demonstrated that the expression of T-cadherin was an independent prognostic factor for the overall survival rate of patients with gastric cancer. This data suggested that the downregulation of T-cadherin may contribute to gastric cancer progression, representing a useful biomarker for predicting the biological behavior and prognosis of gastric cancer. However, no significant association was observed between the expression of VEGF and T-cadherin.

Occurrence of Helicobacter pylori and Epstein-Barr virus infection in endoscopic and gastric cancer patients from Northern Brazil

BACKGROUND

Helicobacter pylori (HP) and Epstein-Barr virus (EBV) have been associated with cancer development. We evaluated the prevalence of HP, HP CagA+ and EBV infection in gastric cancer (GC) samples from adults and in gastric tissues from patients who underwent upper endoscopy (UE).

METHODS

Samples from UE and GC were collected to investigate the presence of HP infection and the HP virulence factor CagA by a urease test and PCR. The presence of EBV was detected by Eber-1 in situ hybridization.

RESULTS

In UE, 85.5% of juvenile patients showed some degree of gastritis (45.3% of patients with mild gastritis and 54.7% with moderate/severe gastritis) and patients with mild gastritis were younger than patients with moderate/severe gastritis. Among adults, 48.7% presented mild gastritis and 51.3% moderate/severe gastritis. HP infection was detected in 0% of normal mucosa, 58.5% of juvenile gastritis patients, 69.2% of adult gastritis patients and 88% of GC patients. In these same groups, HP CagA+ was detected in 0%, 37.7%, 61.5% and 67.2% of tissue samples, respectively. In juvenile patients, HP infection was more common in those with gastritis than in normal samples (p = 0.004). The patients with either HP or HP CagA+ were older than patients without these pathogens (p < 0.05). In juvenile patients, HP infection was more frequent in cases of moderate/severe gastritis than in cases of mild gastritis (p = 0.026). Moreover, in patients with GC, HP infection was more frequent in males than in females (p = 0.023). GC patients with HP CagA+ were older than patients with HP CagA- (p = 0.027). HP CagA+ was more common in intestinal-type than diffuse-type GC (p = 0.012). HP CagA+ was also associated with lymph-node (p = 0.024) and distal (p = 0.005) metastasis. No association between EBV infection and HP infection or any clinicopathological variable was detected.

CONCLUSIONS

Our results suggest that HP is involved in the pathophysiology of severe gastric lesions and in the development of GC, particularly when CagA+ is present. EBV was not the primary pathogenic factor in our samples.

Gastric cancer: prevention, screening and early diagnosis

Gastric cancer continues to be an important healthcare problem from a global perspective. Most of the cases in the Western world are diagnosed at late stages when the treatment is largely ineffective. Helicobacter pylori (H. pylori) infection is a well-established carcinogen for gastric cancer. While lifestyle factors are important, the efficacy of interventions in their modification, as in the use of antioxidant supplements, is unconvincing. No organized screening programs can be found outside Asia (Japan and South Korea). Although several screening approaches have been proposed, including indirect atrophy detection by measuring pepsinogen in the circulation, none of them have so far been implemented, and more study data is required to justify any implementation. Mass eradication of H. pylori in high-risk areas tends to be cost-effective, but its adverse effects and resistance remain a concern. Searches for new screening biomarkers, including microRNA and cancer-autoantibody panels, as well as detection of volatile organic compounds in the breath, are in progress. Endoscopy with a proper biopsy follow-up remains the standard for early detection of cancer and related premalignant lesions. At the same time, new advanced high-resolution endoscopic technologies are showing promising results with respect to diagnosing mucosal lesions visually and targeting each biopsy. New histological risk stratifications (classifications), including OLGA and OLGIM, have recently been developed. This review addresses the current means for gastric cancer primary and secondary prevention, the available and emerging methods for screening, and new developments in endoscopic detection of early lesions of the stomach.

Expression of the EGF family in gastric cancer: downregulation of HER4 and its activating ligand NRG4

Gastric cancer is a major cause of cancer-related deaths in both men and women. The epidermal growth factor receptors are EGFR, HER2, HER3 and HER4. Of the four epidermal growth factor receptors, EGFR and HER2 are well-known oncogenes involved in gastric cancer. Little, however, is known about the role played by HER3 and HER4 in this disease. We obtained paired samples from the tumor and the adjacent normal tissue from the same patient undergoing surgery for gastric cancer. Using RT-qPCR, we quantified the mRNA expression of the four receptors including the HER4 splicing isoforms and all the ligands activating these receptors. Using immunohistochemistry, the protein expression of HER4 was also quantified. We found that HER2 mRNA expression was upregulated in the tumor tissue compared to the matched normal tissue (p = 0.0520). All ligands with affinity for EGFR were upregulated, whereas the expression of EGFR was unchanged. Interestingly, we found the mRNA expression of HER4 (p = 0.0002) and its ligand NRG4 (p = 0.0009) to be downregulated in the tumor tissue compared to the matched normal tissue. HER4 downregulation was demonstrated for all the alternatively spliced isoforms of this receptor. These results support the involvement of EGFR and HER2 in gastric cancer and suggest an interesting association of reduced HER4 expression with development of gastric cancer.

Helicobacter pylori: evidence-based review with a focus on immigrant populations

Helicobacter pylori has been causally linked to a number of diseases, including peptic ulcer disease, gastric adenocarcinoma, mucosa-associated lymphoid tissue lymphoma, and dyspepsia. It is the most prevalent bacterial pathogen in humans, and while the overall prevalence in the United States is about 30 %, the distribution is heterogeneous amongst different ethnic groups. Recent immigrants from high prevalence areas such as Korea, Japan, and China bear an increased burden of its disease and complications. There is clear evidence that treatment of H. pylori resolves peptic ulcer disease, and increasing evidence for protection against development of gastric adenocarcinoma. However, H. pylori treatment failure is common and alternative regimens may be necessary. The following case-based review will highlight these issues, including the epidemiology of H. pylori in the immigrant population, an approach to dyspepsia, and the role of H. pylori in gastric adenocarcinoma.

Current progress toward eradicating Helicobacter pylori in East Asian countries: Differences in the 2013 revised guidelines between China, Japan, and South Korea

New 2013 guidelines on Helicobacter pylori (H. pylori) infection have been published in China, Japan, and South Korea. Like the previous ones, these new guidelines differ between the three countries with regard to the indications for H. pylori eradication, diagnostic methods, and treatment regimens. The most profound change among all of the guidelines is that the Japanese national health insurance system now covers the expenses for all infected subjects up to second-line treatment. This makes the Japanese indications for eradication much wider than those in China and South Korea. With regard to the diagnosis, a serum H. pylori antibody test is not recommended in China, whereas it is considered to be the most reliable method in Japan. A decrease relative to the initial antibody titer of more than 50% after 6-12 mo is considered to be the most accurate method for determining successful eradication in Japan. In contrast, only the urea breath test is recommended after eradication in China, while either noninvasive or invasive methods (except the bacterial culture) are recommended in South Korea. Due to the increased rate of antibiotics resistance, first-line treatment is omitted in China and South Korea in cases of clarithromycin resistance. Notably, the Japanese regimen consists of a lower dose of antibiotics for a shorter duration (7 d) than in the other countries. There is neither 14 d nor bismuth-based regimen in the first-line and second-line treatment in Japan. Such differences among countries might be due to differences in the approvals granted by the governments and national health insurance system in each country. Further studies are required to achieve the best results in the diagnosis and treatment of H. pylori infection based on cost-effectiveness in East Asian countries.

Current evidence of effects of Helicobacter pylori eradication on prevention of gastric cancer

Gastric cancer is the second most common cause of cancer death worldwide and is usually detected at a late stage, except in Korea and Japan where early screening is in effect. Results from animal and epidemiological studies suggest that Helicobacter pylori infection, and subsequent gastritis, promote development of gastric cancer in the infected mucosa. Relatively effective treatment regimens are available to treat H. pylori infection, and in general, mass eradication of the organism is not currently recommended as a gastric cancer prevention strategy. However, regional guidelines vary regarding the indications and recommendations for H. pylori treatment for gastric cancer prevention. In this review, we discuss the results from intervention studies, provide insight regarding current guideline recommendations, and discuss future study directions.

Caffeic acid phenethyl ester (CAPE), an active component of propolis, inhibits Helicobacter pylori peptide deformylase activity

Helicobacter pylori (H. pylori) is a major causative factor for gastrointestinal illnesses, H. pylori peptide deformylase (HpPDF) catalyzes the removal of formyl group from the N-terminus of nascent polypeptide chains, which is essential for H. pylori survival and is considered as a promising drug target for anti-H. pylori therapy. Propolis, a natural antibiotic from honeybees, is reported to have an inhibitory effect on the growth of H. pylori in vitro. In addition, previous studies suggest that the main active constituents in the propolis are phenolic compounds. Therefore, we evaluated a collection of phenolic compounds derived from propolis for enzyme inhibition against HpPDF. Our study results show that Caffeic acid phenethyl ester (CAPE), one of the main medicinal components of propolis, is a competitive inhibitor against HpPDF, with an IC50 value of 4.02 μM. Furthermore, absorption spectra and crystal structural characterization revealed that different from most well known PDF inhibitors, CAPE block the substrate entrance, preventing substrate from approaching the active site, but CAPE does not have chelate interaction with HpPDF and does not disrupt the metal-dependent catalysis. Our study provides valuable information for understanding the potential anti-H. pylori mechanism of propolis, and CAPE could be served as a lead compound for further anti-H. pylori drug discovery.

Symptom-histopathology relation in upper GI endoscopy

OBJECTIVE

The purpose of this article is to examine the correlation between information obtained from patients before endoscopy and histopathological findings.

MATERIAL AND METHODS

One thousand, five hundred and thirty-six patients underwent upper GI endoscopy between January 2011-September 2012, without distinction of age and sex were included in the study. Patients with alarm symptoms, dyspepsia, epigastric pain, gastroesophageal reflux were recorded. Tissue samples taken for histopathological examination and H. pylori screening were evaluated by Giemsa stain. The information given by the patients and histopathological findings were comparatively evaluated.

RESULTS

Six hundred and twenty-four patients (40.6%) were male and 912 (59.4%) were female. Mean age was 45 years (18-90). H. pylori was positive in 416 patients with dyspepsia (58.8%), 172 patients with epigastric pain (54.4%), 52 patients with GER symptoms (28.3%) and 128 patients with alarm symptoms (50.8%). Four patients with dyspepsia (0.6%) and 20 patients with alarm symptoms (7.9%) were diagnosed with stomach cancer.

CONCLUSION

The main factor should be considered as the presence of at least one of the alarm symptoms when planning an upper GI endoscopy in a patient. In the presence of at least one of the alarm symptoms, an upper GI endoscopy should be performed regardless of age. Under the age of 50 and for patients without alarm symptoms, medical treatment can be tried before performing upper GI endoscopy. Patients with GER symptoms but not diagnosed as reflux esophagitis, should be treated long-term even when symptoms decline with initial treatment.

Recent development of gastric cancer prevention

A mass screening program using photofluorography has been used as a secondary prophylaxis of gastric cancer in Japan. However, we are at a turning point for reconsidering the strategy of gastric cancer prevention because of various problems with photofluorography. The shift from current secondary prophylaxis to primary prophylaxis is now required. After a Japanese multicenter randomized controlled trial showed that Helicobacter pylori eradication reduced the incidence of metachronous gastric cancer after endoscopic resection of early gastric cancer, primary prophylaxis of gastric cancer has gained greater attention. The combination of H. pylori eradication as a primary prophylaxis and screening as a secondary prophylaxis is necessary for the elimination of gastric cancer in Japan. The strategy of test, treat and screening for H. pylori infection is effective in reducing the incidence and mortality of gastric cancer in communities with a high incidence of gastric cancer. We have proposed a program of risk stratification based on the presence of H. pylori infection with or without atrophic gastritis followed by targeted interventions.

Molecular assessment of c-H-ras p21 expression in Helicobacter pylori-mediated gastric carcinogenesis

Helicobacter pylori (H. pylori) infection plays a significant role in causing gastric cancer; the exact molecular mechanisms of gastric carcinogenesis have not yet been fully determined. Therefore, this study was planned to examine the role of c-H-ras p21 expression in H. pylori infection at different stages of disease progression from precursor lesions to gastric carcinoma. This study was carried out in 200 patients, consisting of normal gastric mucosa (n = 20), mucosa with chronic gastritis (n = 63), intestinal metaplasia (n = 20), dysplasia (n = 11), and gastric adenocarcinoma (n = 86), in which the H. pylori status have been analysed. The expression of c-H-ras p21 was studied at mRNA as well as protein level using RT-PCR and western blotting, respectively. The localization of c-H-ras p21 was also studied semiquantitatively by immunohistochemistry. The RT-PCR and western blotting results of c-H-ras p21 mRNA and protein expressions were significantly increased in chronic gastritis, intestinal metaplasia, dysplasia, and gastric adenocarcinoma patients, respectively. Immunohistochemical study also showed the increased expression of c-H-ras p21 in the similar way. Overexpression of c-H-ras p21 might be due to H-ras mutation at codon 12 of ras gene family in H. pylori infection. The rate of expression of ras p21 was higher in the H. pylori-infected precursor lesions, chronic gastritis 49/56 (87.5%), intestinal metaplasia 16/17 (94%), and dysplasia 9/11(82%) whereas in the case of H. pylori negative cases these groups, show 12.5, 5.9, and 18.2%, respectively. The data suggested that H. pylori infection may increase the expression of c-H-ras p21 early in the process of gastric carcinogenesis.

Gastric diseases in Mongolian gerbils infected with different strains of Helicobacter pylori

Helicobacter pylori (H.pylori) is a bacterium responsible for one of the most widespread infections found in humans. It colonizes the gastric mucosa and can result in chronic gastritis and gastric cancer. The incidence of spontaneous gastric gastritis is low in Mongolian gerbils, and spontaneous H.pylori infection can not be detected in this animal. Since H.pylori-related gastric diseases in Mongolian gerbils are very similar to those in humans, they have been considered as ideal animals to establish H.pylori infection models. However, different strains of H.pylori may induce different types of pathologic changes in Mongolian gerbils. Clarification of the pathogenic mechanisms of different strains of H.pylori may provide a theoretical basis for screening appropriate H.pylori strains and directing individualized treatment in patients with H.pylori-related gastric diseases. In this paper, we review the recent progress in research of gastric diseases in Mongolian gerbils infected with different strains of H.pylori.