Epistatic SNP interaction of ERCC6 with ERCC8 and their joint protein expression contribute to gastric cancer/atrophic gastritis risk.
ABSTRACT: Excision repair cross-complementing group 6 and 8 (ERCC6 and ERCC8) are two indispensable genes for the initiation of transcription-coupled nucleotide excision repair pathway. This study aimed to evaluate the interactions between single nucleotide polymorphisms of ERCC6 (rs1917799) and ERCC8 (rs158572 and rs158916) in gastric cancer and its precancerous diseases. Besides, protein level analysis were performed to compare ERCC6 and ERCC8 expression in different stages of gastric diseases, and to correlate SNPs jointly with gene expression. Sequenom MassARRAY platform method was used to detect polymorphisms of ERCC6 and ERCC8 in 1916 subjects. In situ ERCC6 and ERCC8 protein expression were detected by immunohistochemistry in 109 chronic superficial gastritis, 109 chronic atrophic gastritis and 109 gastric cancer cases. Our results demonstrated pairwise epistatic interactions between ERCC6 and ERCC8 SNPs that ERCC6 rs1917799-ERCC8 rs158572 combination was associated with decreased risk of chronic atrophic gastritis and increased risk of gastric cancer. ERCC6 rs1917799 also showed a significant interaction with ERCC8 rs158916 to reduce gastric cancer risk. The expressions of ERCC6, ERCC8 and ERCC6-ERCC8 combination have similarities that higher positivity was observed in chronic superficial gastritis compared with chronic atrophic gastritis and gastric cancer. As for the effects of ERCC6 and ERCC8 SNPs on the protein expression, single SNP had no correlation with corresponding gene expression, whereas the ERCC6 rs1917799-ERCC8 rs158572 pair had significant influence on ERCC6 and ERCC6-ERCC8 expression. In conclusion, ERCC6 rs1917799, ERCC8 rs158572 and rs158916 demonstrated pairwise epistatic interactions to associate with chronic atrophic gastritis and gastric cancer risk. The ERCC6 rs1917799-ERCC8 rs158572 pair significantly influence ERCC6 and ERCC6-ERCC8 expression.
Project description:<h4>Background</h4>Excision repair cross-complementing group 6 and 8 (ERCC6 and ERCC8) have been implicated in ailments such as genetic diseases and cancers. However, the relationship between individual and joint expressions of ERCC6/ERCC8 and clinicopathological parameters as well as prognosis of gastric cancer (GC) still remains unclear.<h4>Methods</h4>In this study, protein expressions of ERCC6, ERCC8 and ERCC6-ERCC8 were detected by immunohistochemistry (IHC) in 109 paired GC and para-cancerous normal tissue samples. The mRNA expression was detected in 36 pairs of tissue samples. IHC results and RNA-seq data extracted from The Cancer Genome Atlas (TCGA) were used to explore the clinical value of ERCC6 and ERCC8 expression in GC. We further conducted protein-protein interaction analysis, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, gene set enrichment analysis, and gene-gene interaction analysis to explore the function and regulation networks of ERCC6 and ERCC8 in GC.<h4>Results</h4>Individual and joint ERCC6/ERCC8 expression were significantly higher in adjacent normal mucosa compared with GC tissues. ERCC6 mRNA expression showed no difference in GC and paired tissues, while ERCC8 mRNA was significantly decreased in GC tissues. Protein expression of ERCC6, ERCC8, double negative ERCC6-ERCC8 and double positive ERCC6-ERCC8 and overexpressed ERCC6 mRNA were related to better clinicopathologic parameters, while overexpressed ERCC8 mRNA suggested worse parameters. Univariate survival analysis indicated that the OS was longer when ERCC6 protein expression and ERCC8 mRNA expression increased, and double negative ERCC6-ERCC8 expression was associated with a short OS. Bioinformatics analyses showed ERCC6 and ERCC8 were associated with nucleotide excision repair (NER) pathway, and six and ten gene sets were figured out to be related with ERCC6 and ERCC8, respectively. KEGG pathway showed that ERCC6/ERCC8 related gene sets were mainly involved in the regulation of PI3K/AKT/mTOR pathway. Direct physical interactions were found between ERCC6 and ERCC8.<h4>Conclusions</h4>Individual and joint expressions of ERCC6/ERCC8 were associated with clinical features of GC. Protein expression of ERCC6, ERCC6-ERCC8, and mRNA expression of ERCC8 were related to prognosis of GC. ERCC6 and ERCC8 primarily function in the NER pathway, and may regulate GC progression through the regulation of PI3K/AKT/mTOR pathway.
Project description:<h4>Background</h4>The aim of this study was to investigate the interaction effects of pri-let-7a-1 rs10739971 with pepsinogen C (PGC) and excision repair cross complementing group 6 (ERCC6) gene polymorphisms and its association with the risks of gastric cancer and atrophic gastritis. We hoped to identify miRNA polymorphism or a combination of several polymorphisms that could serve as biomarkers for predicting the risk of gastric cancer and its precancerous diseases.<h4>Methods</h4>Sequenom MassARRAY platform method was used to detect polymorphisms of pri-let-7a-1 rs10739971 G ? A, PGC rs4711690 C ? G, PGC rs6458238 G ? A, PGC rs9471643 G ? C, and ERCC6 rs1917799 in 471 gastric cancer patients, 645 atrophic gastritis patients and 717 controls.<h4>Results</h4>An interaction effect of pri-let-7a-1 rs10739971 polymorphism with ERCC6 rs1917799 polymorphism was observed for the risk of gastric cancer (P interaction?=?0.026); and interaction effects of pri-let-7a-1 rs10739971 polymorphism with PGC rs6458238 polymorphism (P interaction?=?0.012) and PGC rs9471643 polymorphism (P interaction?=?0.039) were observed for the risk of atrophic gastritis.<h4>Conclusion</h4>The combination of pri-let-7a-1 rs10739971 polymorphism and ERCC6 and PGC polymorphisms could provide a greater prediction potential than a single polymorphism on its own. Large-scale studies and molecular mechanism research are needed to confirm our findings.
Project description:Gastric cancer is an important health problem because it is difficult to diagnose and treat in advanced stage. This makes that the prognosis of gastric cancer patients remains scarce. Currently it is known that the cause of gastric cancer is attributed to chronic infection with Helicobacter pylori. Its persistent infection leads to development of chronic atrophic gastritis that is considered as a predecessor stage of intestinal-type gastric cancer. The understanding of the alteration of molecular mechanisms during the early stages of the development of gastric cancer, and the identification of their potential biomarkers can allow a rapid diagnosis that leads to an improvement diagnosis and increase the patient’s prognosis. We analyzed gene expression profiles of patients with chronic atrophic gastritis and gastric cancer through microarray analysis, functional enrichment analysis and validation of gene expression by quantitative PCR. Gene expression profiles in patients with chronic atrophic gastritis showed molecular changes of the gastric mucosa, which leads to intestinal metaplasia and subsequently, gastric cancer. In gastric cancer the gene expression profile showed the stage of tumor progression, the product of these genes are potential biomarkers of early stages of cancer that can be potential therapeutic targets. Accordingly, the transcriptome analysis revealed several gene groups are related to development of chronic atrophic gastritis, some of which were inhibited in gastric cancer patients. The increased expression of CLDN1, CLDN7, OLFM4, c-Myc and MMP-9 genes in chronic atrophic gastritis and gastric cancer point outs to their use as promising biomarkers for the early diagnosis of gastric cancer. Overall design: RNA from 11 biopsies from patients with follicular gastritis, chronic atrophic gastritis and gastric cancer were analized by microarrays. Gene Set Enrichment Analysis, and differential expression analysis with subsequent funtional annotation was performed for each group of histological lesions.
Project description:<h4>Background</h4>Chronic inflammation plays a causal role in gastric tumor initiation. The identification of predictive biomarkers from gastric inflammation to tumorigenesis will help us to distinguish gastric cancer from atrophic gastritis and establish the diagnosis of early-stage gastric cancer. Phospholipase C epsilon 1 (PLC?1) is reported to play a vital role in inflammation and tumorigenesis. This study was aimed to investigate the clinical significance of PLC?1 in the initiation and progression of gastric cancer.<h4>Methodology/principal findings</h4>Firstly, the mRNA and protein expression of PLC?1 were analyzed by reverse transcription-PCR and Western blotting in normal gastric mucous epithelial cell line GES-1 and gastric cancer cell lines AGS, SGC7901, and MGC803. The results showed both mRNA and protein levels of PLC?1 were up-regulated in gastric cancer cells compared with normal gastric mucous epithelial cells. Secondly, this result was confirmed by immunohistochemical detection in a tissue microarray including 74 paired gastric cancer and adjacent normal tissues. Thirdly, an independence immunohistochemical analysis of 799 chronic atrophic gastritis tissue specimens demonstrated that PLC?1 expression in atrophic gastritis tissues were down-regulated since PLC?1 expression was negative in 524 (65.6%) atrophic gastritis. In addition, matched clinical tissues from atrophic severe gastritis and gastric cancer patients were used to further confirm the previous results by analyzing mRNA and protein levels expression of PLC?1 in clinical samples.<h4>Conclusions/significances</h4>Our results suggested that PLC?1 protein may be a potential biomarker to distinguish gastric cancer from inflammation lesion, and could have great potential in applications such as diagnosis and pre-warning of early-stage gastric cancer.
Project description:Intestinal-type gastric cancer is preceded by premalignant lesions including chronic atrophic gastritis and intestinal metaplasia. In this study, we performed a scRNA-seq survey of 56,440 cells from thirteen gastric antral mucosa biopsies from nine patients with Non-atrophic gastritis (NAG), CAG, IM or early gastric cancer (EGC), and constructed a single-cell transcriptome atlas for gastric premalignant and early-malignant lesions. The thirteen biopsies, including three wild superficial gastritis (NAG) ones, three CAG ones, six IM ones and one EGC , spanned the cascade from gastritis to early gastric cancer.For each biopsy, we isolated single cells without prior selection for cell types and utilized the 10x Chromium platform to generate RNA-seq data. After removing low-quality cells (Methods), a total of 32, 332 cells that passed the quality control were retained for subsequent analysis, which yielded a median of 1941 detected genes per cell. Overall design: a scRNA-seq survey of 56,440 cells from thirteen gastric antral mucosa biopsies from nine patients with Non-atrophic gastritis (NAG), Chronic atrophic gastritis (CAG), Intestinal metaplasia (IM) or early gastric cancer (EGC), using 10X genomics.
Project description:Indonesia is a big country with multiethnic populations whose gastric cancer risks have not been elucidated. We performed a nationwide survey and obtained histological specimens from 1053 individuals in 19 cities across the country. We examined the gastric mucosa, the topography, the atrophic gastritis risk factors, and the gastric cancer risk scores. Almost half (46.1%) of the patients with dyspeptic symptoms had histological abnormalities; chronic (36.3%) and atrophic gastritis (28.9%) being the most frequent. Individuals of the Timor ethnicity had the highest prevalence of acute (52.6%) and chronic gastritis (68.4%), even those negative for H. pylori. Our topographic analysis showed the majority of patients had predominantly antral acute and chronic gastritis. A multivariate logistic regression model showed age (Odds ratio [OR], 1.107), Timor ethnicity (OR, 8.531), and H. pylori infection (OR, 22.643) as independent risk factors for presence of atrophic gastritis. In addition, the gastric cancer risk score was highest in those from Timor, Papuan, and Bugis ethnic populations. Overall, Indonesia is a low-risk gastric cancer country. However, several ethnic groups displayed severe gastric mucosa symptoms suggesting policy makers should focus on those ethnic groups to perform gastric cancer screenings and to eradicate H. pylori.
Project description:Prevalence of chronic gastritis has markedly declined in developed populations during the past decades. However, chronic gastritis is still one of the most common serious pandemic infections with such severe killing sequelae as peptic ulcer or gastric cancer. Globally, on average, even more than half of people may have a chronic gastritis at present. Helicobacter pylori infection in childhood is the main cause of chronic gastritis, which microbial origin is the key for the understanding of the bizarre epidemiology and course of the disease. A life-long and aggressive inflammation in gastritis results in destruction (atrophic gastritis) of stomach mucosa with time (years and decades). The progressive worsening of atrophic gastritis results subsequently in dysfunctions of stomach mucosa. Atrophic gastritis will finally end up in a permanently acid-free stomach in the most extreme cases. Severe atrophic gastritis and acid-free stomach are the highest independent risk conditions for gastric cancer known so far. In addition to the risks of malignancy and peptic ulcer, acid-free stomach and severe forms of atrophic gastritis may associate with failures in absorption of essential vitamins, like vitamin B12, micronutrients (like iron, calcium, magnesium and zinc), diet and medicines.
Project description:<h4>Background</h4>Infection with Helicobacter pylori is considered a potential risk of developing gastric cancer in association with contributing host genetic factor. IL-1? and IL-1RN polymorphisms appear to maintain and promote Helicobacter pylori infection and to stimulate neoplastic growth of the gastric mucosa.<h4>Objective and methods</h4>In order to elucidate the effect of these polymorphisms in combination with gastric cancer in a population from northwestern Algeria, a case-control study was carried out on 79 patients infected with H. pylori with chronic atrophic gastritis and/or gastric carcinoma, and 32 subjects were recruited as case-control. IL-1?-31 bi-allelic and IL-1?-511 bi-allelic polymorphisms and IL-1RN penta-allelic were genotyped.<h4>Results</h4>IL-1?-31C was associated with an increased risk of developing gastric carcinoma (OR=4.614 [1.43-14.81], p=0.01). However, IL-1RN2 heterozygous allele type was significantly associated with chronic atrophic gastritis (OR=4.2 [1.23-3.61], p=0.022). IL-1?-511T was associated with an increased risk of development of chronic atrophic gastritis (OR=4.286 [1.54-11.89], p=0.005).<h4>Conclusion</h4>IL-1? and IL-1RN polymorphisms associated with H. pylori infection contribute to the development of chronic atrophic gastritis and gastric carcinomas in an Algerian population. The alleles IL-1?-31C and IL-1RN were associated with an increased risk of developing gastric carcinoma, and IL-1?-511T with an increased risk of developing chronic atrophic gastritis with no significant association of developing gastric carcinoma.
Project description:<h4>Background</h4>Pepsinogen C (PGC) plays an important role in sustaining the cellular differentiation during the process of gastric carcinogenesis. This study aimed to assess the role of PGC tagSNPs and their interactions with Helicobacter pylori (H. pylori) in the development of gastric cancer and its precursor, atrophic gastritis.<h4>Methods</h4>Four PGC tagSNPs (rs6941539, rs6912200, rs3789210 and rs6939861) were genotyped by Sequenom MassARRAY platform in a total of 2311 subjects consisting of 642 gastric cancer, 774 atrophic gastritis, and 895 healthy control subjects. The mRNA and protein expression levels of PGC in gastric tissues and in serum were respectively measured by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), immunohistochemistry, and Eenzyme-linked immunoabsorbent assay (ELISA).<h4>Results</h4>We found associations between PGC rs3789210 CG/GG genotypes and reduced gastric cancer risk and between PGC rs6939861 A variant allele and increased risks of both gastric cancer and atrophic gastritis. As for the haplotypes of PGC rs6941539-rs6912200-rs3789210-rs6939861 loci, the TTCA and TTGG haplotypes were respectively associated with increased and reduced risks of both gastric cancer and atrophic gastritis; additionally, the CTCA haplotype was associated with increased atrophic gastritis risk. Very interestingly, rs6912200 CT/TT genotypes had a positive interaction with H. pylori, synergistically elevating the gastric cancer risk. Moreover, healthy subjects who carried rs6912200 CT, TT and CT/TT variant genotypes had lower histological and serum expression levels of PGC protein.<h4>Conclusions</h4>Our findings highlight an important role of PGC rs3789210 and rs6939861 in altering susceptibility to atrophic gastritis and/or gastric cancer. Moreover, people who carry rs6912200 variant genotypes exhibit higher gastric cancer risk in case of getting H. pylori infection, which strongly suggest a necessity of preventing and/or eliminating H. pylori infection in those individuals.
Project description:We examined the development of gastric cancer risk screening, from rat pepsinogen studies in an experimental rat gastric carcinogenesis model induced with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and human pepsinogen studies in the 1970s and 1980s to the recent "ABC method" for human gastric cancer risk screening. First, decreased expression or absence of a major pepsinogen isozyme, PG1, was observed in the rat gastric mucosa from the early stages of gastric carcinogenesis to adenocarcinomas following treatment with MNNG. In the 1980s, decreases in PGI in the human gastric mucosa and serum were identified as markers of atrophic gastritis. In the 1990s, other researchers revealed that chronic infection with Helicobacter pylori (Hp) causes atrophic gastritis and later gastric cancer. In the 2000s, a gastric cancer risk screening method combining assays to detect serum anti-Hp IgG antibody and serum PGI and PGII levels, the "ABC method", was established. Eradication of Hp and endoscopic follow-up examination after the ABC method are recommended to prevent gastric cancer.