Gastric Mucosa Tissues Research Articles

Methionine restriction promotes cisplatin sensitivity of gastric cancer resistant cells by down-regulating circ-CDK13 level

BackgroundMethionine restriction (MR) is a research direction in the treatment of gastric cancer (GC). The aim of this study was to investigate the molecular mechanism of MR on enhancing cisplatin (DDP) sensitivity of drug-resistant GC cells. MethodsTwenty pairs of GC tissues and adjacent normal gastric mucosa tissues were collected. DDP-resistant cell lines (KATO/DDP and MKN45/DDP), mouse model of GC and GC patient-derived organoid (PDO) models were established. Lentivirus-mediated METase overexpression was used for MR. Cell viability and apoptosis were detected by MTT assay and flow cytometry. Western blotting was used to detect multi-drug resistance-1 (MDR1), MDR-associated protein 1 (MRP1) eukaryotic initiation factor 4A-Ⅲ (EIF4A3), and METase protein expressions. The levels of circRNAs were detected by qRT-PCR. Tumor volume and weight were measured. The proliferation of tumor cells was detected by immunohistochemical staining. ResultsThe differentially expressed circRNAs of GC were screened in Gene Expression Omnibus database. MR in KATO/DDP and MKN45/DDP cells significantly down-regulated circ-CDK13 level. Overexpression of circ-CDK13 significantly inhibited apoptosis of sensitive cells (KATO III and MKN45). Interference with circ-CDK13 significantly promoted apoptosis of drug-resistant cells (KATO/DDP and MKN45/DDP). MR enhanced the DDP sensitivity of GC resistant cells, GC PDO and GC mice by down-regulating circ-CDK13. EIF4A3 binds to the downstream flanking sequence of circ-CDK13, and interference with EIF4A3 reduces circ-CDK13 levels, but does not affect CDK13. The expressions of circ-CDK13 and EIF4A3 in GC clinical samples were increased and positively correlated. Simultaneously overexpression of METase and EIF4A3 in resistant cells inhibited apoptosis, and further interference with circ-CDK13 reversed this effect. ConclusionMR inhibits circ-CDK13 level by down-regulating EIF4A3, thereby increasing the sensitivity of GC drug-resistant cells to DDP.

Jianpi-Huatan-Huoxue-Anshen formula ameliorates gastrointestinal inflammation and microecological imbalance in chemotherapy-treated mice transplanted with H22 hepatocellular carcinoma.

Jianpi-Huatan-Huoxue-Anshen formula [Tzu-Chi cancer-antagonizing & life-protecting II decoction (TCCL)] is a Chinese medical formula that has been clinically shown to reduce the gastrointestinal side effects of chemotherapy in cancer patients and improve their quality of life. However, its effect and mechanism on the intestinal microecology after chemotherapy are not yet clear. To discover the potential mechanisms of TCCL on gastrointestinal inflammation and microecological imbalance in chemotherapy-treated mice transplanted with hepatocellular carcinoma (HCC). Ninety-six mice were inoculated subcutaneously with HCC cells. One week later, the mice received a large dose of 5-fluorouracil by intraperitoneal injection to establish a HCC chemotherapy model. Thirty-six mice were randomly selected before administration, and feces, ileal tissue, and ileal contents were collected from each mouse. The remaining mice were randomized into normal saline, continuous chemotherapy, Yangzheng Xiaoji capsules-treated, and three TCCL-treated groups. After treatment, feces, tumors, liver, spleen, thymus, stomach, jejunum, ileum, and colon tissues, and ileal contents were collected. Morphological changes, serum levels of IL-1β, IL-6, IL-8, IL-10, IL-22, TNF-α, and TGF-β, intestinal SIgA, and protein and mRNA expression of ZO-1, NF-κB, Occludin, MUC-2, Claudin-1, and IκB-α in colon tissues were documented. The effect of TCCL on the abundance and diversity of intestinal flora was analyzed using 16S rDNA sequencing. TCCL treatment improved thymus and spleen weight, thymus and spleen indexes, and body weight, decreased tumor volumes and tumor tissue cell density, and alleviated injury to gastric, ileal, and colonic mucosal tissues. Among proteins and genes associated with inflammation, IL-10, TGF-β, SIgA, ZO-1, MUC-2, and Occludin were upregulated, whereas NF-κB, IL-1β, IL-6, TNF-α, IL-22, IL-8, and IκB-α were downregulated. Additionally, TCCL increased the proportions of fecal Actinobacteria, AF12, Adlercreutzia, Clostridium, Coriobacteriaceae, and Paraprevotella in the intermediate stage of treatment, decreased the proportions of Mucipirillum, Odoribacter, RF32, YS2, and Rikenellaceae but increased the proportions of p_Deferribacteres and Lactobacillus at the end of treatment. Studies on ileal mucosal microbiota showed similar findings. Moreover, TCCL improved community richness, evenness, and the diversity of fecal and ileal mucosal flora. TCCL relieves pathological changes in tumor tissue and chemotherapy-induced gastrointestinal injury, potentially by reducing the release of pro-inflammatory factors to repair the gastrointestinal mucosa, enhancing intestinal barrier function, and maintaining gastrointestinal microecological balance. Hence, TCCL is a very effective adjuvant to chemotherapy.

Clinical Analysis of Multidrug Resistance-Related Protein Expression in Gastric Cancer Cells

Objective: This study aims to clinically analyze the expression of multidrug resistance-related proteins in gastric cancer cells. Methods: In this study, archival paraffin blocks from 50 surgical specimens of gastric cancer collected in our hospital between 2021 and 2022 were included. Each specimen included tumor lesion tissue and normal gastric mucosa tissue located more than 5 cm away from the cancer. Immunohistochemistry was performed to detect P-glycoprotein (P-gp), glutathione S-transferase pi (GST-π), and B-cell lymphoma-extra-large (Bcl-xL) expression, and the relevant data were collected and analyzed. Results: The positive expression rates and high expression levels of P-gp, GST-π, and Bcl-xL in gastric cancer tissues were significantly higher than in normal gastric mucosa tissues (p < 0.05). The expression of multidrug resistance proteins (P-gp, GST-π, Bcl-xL) in gastric cancer was not associated with patient clinical characteristics (tumor clinical stage, depth of invasion, and lymph node metastasis) (p > 0.05); Bcl-xL expression level was positively correlated with tumor differentiation degree (p < 0.05). Conclusion: The results of this study reveal the expression patterns of multidrug resistance-related proteins in gastric cancer tissues and shed light on the relationship between the expression of these proteins and multidrug resistance in gastric cancer.

Polypoid heterotopic gastric mucosa: in terminal ileum causing extensive lower gastrointestinal bleeding without Meckel’s diverticulum: a case report

BackgroundHeterotopic gastric mucosa (HGM) can be located in various parts of the gastrointestinal tract. As a rare anomaly in the small intestine, it can become complicated by intussusception, obstruction, gastrointestinal bleeding, and even peritonitis, leading to death.Case presentationThis case report focuses on a 12-year-old Middle Eastern boy who presented with hematochezia and abdominal pain for a couple of days. A tagged Red blood cell (RBC) scan and Technetium scan revealed gastrointestinal bleeding at the lower abdomen, highly suggestive of the diagnosis of Meckel’s diverticulum. Subsequently, exploratory laparotomy revealed contiguous and scattered mucosal lesions with multiple polyps of various sizes in the terminal ileum. Meckel’s diverticulum was absent, and the patient was treated with resection and primary anastomosis. The resected tissue revealed extensive ectopic gastric mucosa and polypoid tissues. The patient recovered uneventfully and was discharged four days after the surgery. The symptoms did not recur within six months after his surgery.ConclusionOur case demonstrated that despite the rarity of multiple polypoid gastric heterotopias in the terminal ileum, it should be considered as one of the differential diagnoses of gastrointestinal tract bleeding.

Potential mechanism of sea cucumber gut peptides in protecting ethanol-induced gastric mucosal injury

Alcoholic gastric injury is a prevalent condition that can result in gastric ulcers. This research delves into the protective effects of sea cucumber gut peptides, Val-Thr-Pro-Tyr (VTPY) and Val-Leu-Leu-Tyr (VLLY), on ethanol-induced gastric injury. These peptides significantly alleviate the pathological symptoms of gastric tissue affected by ethanol, reducing ulcer area and index, epithelial cell loss, submucosal edema, and inflammatory infiltration. High doses of VTPY and VLLY resulted in a significant decrease in ulcer index, with reductions from 5.38 to 2.63 and 1.13, respectively (P < 0.05). Moreover, the levels of P–NF-κB/p65 expression decreased by 33.47% and 54.27%, while myeloperoxidase (MPO) activity decreased by 42.98% and 55.33%, respectively. These treatments also effectively suppressed inflammatory cytokine expression and inhibited macrophage infiltration, ultimately alleviating the inflammatory response in gastric mucosal tissue. They also enhance mitochondrial function by regulating factors associated with mitochondrial dynamics and increasing succinate dehydrogenase (SDH) activity. Furthermore, they alleviate endoplasmic reticulum stress by reducing the immunoglobulin heavy chain-binding protein (Bip), phosphorylated eukaryotic translation initiation factor 2 alpha (P-eIF2α), and activating transcription factor 4 (ATF4) expression levels. Ultimately, high doses of VTPY and VLLY increased the B-cell lymphoma-extra large to B-cell lymphoma-2 associated death promoter ratio (Bcl-XL/Bad ratio) by 138.68% and 247.99%, respectively, while the expression level of cleaved-caspase 3 decreased by 35.26% and 48.22%, thereby preventing the activation of the apoptotic pathway. Sea cucumber gut peptides VTPY and VLLY exhibit effective anti-inflammatory and anti-apoptotic properties, along with anti-endoplasmic reticulum stress effects, by inhibiting the ATF4/Bcl-2 signaling pathway, thus effectively shielding against ethanol-induced gastric damage. VLLY appears to be more potent in this aspect.

Mechanism of Weiwei granules in the treatment of chronic active Helicobacter pylori gastritis with atrophy based on the TLR4/NF-κB/COX-2 inflammatory signaling pathway.

Our paper aimed to elucidate the mechanism of Weiwei granules in the treatment of Helicobacter pylori (Hp)-positive chronic atrophic gastritis (CAG) based on the TLR4/NF-κB/COX-2 inflammatory signaling pathway. Hp-positive CAG patients were randomized into the control group (treated with quadruple therapy) or the observation group (treated with Weiwei granules based on the control group). The clinical efficacy, Hp clearance rate, and efficacy of traditional Chinese medicine (TCM) symptoms were compared between the two groups after six months of treatment. The scores of various histopathology variables, serum levels of inflammatory factors (interleukin-6 [IL-6], interleukin-8 [IL-8], and tumor necrosis factor-alpha [TNF-α]), gastrin-17 (G-17) and motilin (MTL), pepsinogen (PG) I and PG II, as well as serum levels of gastrointestinal hormone endothelin (ET), epidermal growth factor (EGF), and calcitonin gene-related peptide (CGRP), were compared between the two groups before and after treatment. TLR4, NF-κB, and COX-2 mRNA levels were compared in gastric mucosal tissues before and after treatment in the two groups. After treatment, the clinical efficacy, Hp clearance rate, and efficacy of TCM symptoms of patients in the observation group were higher than those in the control group. After treatment, the scores of various histopathology variables, serum levels of inflammatory factors (IL-6, IL-8, and TNF-α), gastrointestinal hormones (ET and EGF), and the expression levels of TLR4, NF-κB, and COX-2 mRNA in the gastric mucosal tissues were lower and G-17, MTL, CGRP, and PG I levels were higher in the observation group than in the control group. Weiwei granules can effectively improve Hp-positive CAG patients and reduce the expression levels of TLR4, NF-κB, and COX-2.

The demethylase ALKBH5 mediates ZKSCAN3 expression through the m6A modification to activate VEGFA transcription and thus participates in MNNG-induced gastric cancer progression

N-Nitroso compounds (NOCs) are recognized as important factors that promote gastric cancer development, but the specific effects and potential mechanisms by which NOC exposure promotes gastric cancer are still poorly understood. In this study, we explored the effects and potential molecular mechanisms of NOCs on the promotion of gastric cancer using methylnitronitrosoguanidine (MNNG), a classical direct carcinogen of NOC. The results of in vivo and in vitro experiments showed that chronic and low-concentration MNNG exposure significantly promoted the malignant progression of tumors, including cell migration, cell invasion, vasculogenic mimicry (VM) formation, cell spheroid formation, stem cell-like marker expression, and gastric cancer growth and metastasis. Mechanistically, we revealed that demethylase ALKBH5 regulated the level of the N6‑methyladenosine (m6A) modification in the 3′UTR and CDS region of the ZKSCAN3 mRNA to promote ZKSCAN3 expression, mediated the binding of ZKSCAN3 to the VEGFA promoter region to regulate VEGFA transcription, and participated in MNNG-induced gastric cancer cell migration, invasion, VM formation, cell spheroid formation, stem cell-like marker expression and ultimately gastric cancer progression. In addition, our study revealed that ALKBH5-ZKSCAN3-VEGFA signaling was significantly activated during MNNG-induced gastric carcinogenesis, and further studies in gastric cancer patients showed that ALKBH5, ZKSCAN3, and VEGFA expression were upregulated in cancers compared with paired gastric mucosal tissues, that ALKBH5, ZKSCAN3, and VEGFA could serve as important biomarkers for determining patient prognosis, and that the molecular combination showed greater prognostic value. These findings provide a theoretical basis for developing gastric cancer interventions for NOCs and for determining gastric cancer progression.

Helicobacter pylori disrupts gastric mucosal homeostasis by stimulating macrophages to secrete CCL3

BackgroundHelicobacter pylori (H. pylori) is the predominant etiological agent of gastritis and disrupts the integrity of the gastric mucosal barrier through various pathogenic mechanisms. After H. pylori invades the gastric mucosa, it interacts with immune cells in the lamina propria. Macrophages are central players in the inflammatory response, and H. pylori stimulates them to secrete a variety of inflammatory factors, leading to the chronic damage of the gastric mucosa. Therefore, the study aims to explore the mechanism of gastric mucosal injury caused by inflammatory factors secreted by macrophages, which may provide a new mechanism for the development of H. pylori-related gastritis.MethodsThe expression and secretion of CCL3 from H. pylori infected macrophages were detected by RT-qPCR, Western blot and ELISA. The effect of H. pylori-infected macrophage culture medium and CCL3 on gastric epithelial cells tight junctions were analyzed by Western blot, immunofluorescence and transepithelial electrical resistance. EdU and apoptotic flow cytometry assays were used to detect cell proliferation and apoptosis levels. Dual-luciferase reporter assays and chromatin immunoprecipitation assays were used to study CCL3 transcription factors. Finally, gastric mucosal tissue inflammation and CCL3 expression were analyzed by hematoxylin and eosin staining and immunohistochemistry.ResultsAfter H. pylori infection, CCL3 expressed and secreted from macrophages were increased. H. pylori-infected macrophage culture medium and CCL3 disrupted gastric epithelial cells tight junctions, while CCL3 neutralizing antibody and receptor inhibitor of CCL3 improved the disruption of tight junctions between cells. In addition, H. pylori-infected macrophage culture medium and CCL3 recombinant proteins stimulated P38 phosphorylation, and P38 phosphorylation inhibitor improved the disruption of tight junctions between cells. Besides, it was identified that STAT1 was a transcription factor of CCL3 and H. pylori stimulated macrophage to secret CCL3 through the JAK1-STAT1 pathway. Finally, after mice were injected with murine CCL3 recombinant protein, the gastric mucosal injury and inflammation were aggravated, and the phosphorylation level of P38 was increased.ConclusionsIn summary, our findings demonstrate that H. pylori infection stimulates macrophages to secrete CCL3 via the JAK1-STAT1 pathway. Subsequently, CCL3 damages gastric epithelial tight junctions through the phosphorylation of P38. This may be a novel mechanism of gastric mucosal injury in H. pylori-associated gastritis.

Exploration of lncRNA/circRNA-miRNA-mRNA network in patients with chronic atrophic gastritis in Tibetan plateau areas based on DNBSEQ-G99 RNA sequencing

A higher incidence of chronic atrophic gastritis (CAG) is generally considered as a precancerous lesion in gastric cancer (GC). The aim of this study was to identify potential molecules involved in the pathogenesis of CAG in the Tibetan plateau, hoping to help the diagnosis and management of the disease. Atrophic and non-atrophic gastric mucosal tissue samples were collected from seven patients with chronic gastritis (CG). Differentially expressed lncRNAs, circRNAs, miRNAs, and mRNAs between CAG and chronic non-atrophic gastritis (CNAG) groups were identified based on DNBSEQ-G99 RNA sequencing. Subsequently, competitive endogenous RNA (ceRNA) regulatory networks (lncRNA/circRNA-miRNA-mRNA networks) were constructed. Two datasets (GSE153224 and GSE163416), involving data from non-Tibetan plateau areas, were used to further screen out Tibetan plateau key mRNAs, followed by the common genes of Tibetan plateau key and ferroptosis-related mRNAs were also identified. Functional enrichment analyses were performed to investigate the biological functions of Tibetan plateau mRNAs in the CAG. A total of seven lncRNA-miRNA-mRNA relationship pairs and 424 circRNA-miRNA-mRNA relationship pairs were identified in this study. The relationship pairs of hsa_circ_0082984-hsa-miR-204-5p-CACNG8, lncRNA DRAIC/has_circ_0008561-hsa-miR-34a-5p-AR/GXYLT2, lncRNA GAS1RR/RGMB-AS1/hsa_circ_0008561-hsa-miR-3614-5p-TMEM216/SUSD5, and LINC00941/hsa_circ_0082984-hsa-miR-873-3p-TMC5 can be involved in the pathogenesis of CAG. Additionally, eight common genes of Tibetan plateau key and ferroptosis-related differentially expressed mRNAs (DEmRNAs) (CBS, SLC2A4, STAT3, ALOX15B, ATF3, IDO1, NOX4, and SOCS1) were identified in CAG. The common genes of Tibetan plateau key and ferroptosis-related DEmRNAs can play a role in the JAK-STAT signaling pathway. This study identified important molecular biomarkers that may be involved in regulating the pathological mechanisms of CAG in the Tibetan plateau, which provides potential research directions for future research.

Mitochondrial dysfunction induced by HIF-1α under hypoxia contributes to the development of gastric mucosal lesions.

Hypoxia is an important characteristic of gastric mucosal diseases, and hypoxia-inducible factor-1α (HIF-1α) contributes to microenvironment disturbance and metabolic spectrum abnormalities. However, the underlying mechanism of HIF-1α and its association with mitochondrial dysfunction in gastric mucosal lesions under hypoxia have not been fully clarified. To evaluate the effects of hypoxia-induced HIF-1α on the development of gastric mucosal lesions. Portal hypertensive gastropathy (PHG) and gastric cancer (GC) were selected as representative diseases of benign and malignant gastric lesions, respectively. Gastric tissues from patients diagnosed with the above diseases were collected. Portal hypertension (PHT)-induced mouse models in METTL3 mutant or NLRP3-deficient littermates were established, and nude mouse gastric graft tumour models with relevant inhibitors were generated. The mechanisms underlying hypoxic condition, mitochondrial dysfunction and metabolic alterations in gastric mucosal lesions were further analysed. HIF-1α, which can mediate mitochondrial dysfunction via upregulation of METTL3/IGF2BP3-dependent dynamin-related protein 1 (Drp1) N6-methyladenosine modification to increase mitochondrial reactive oxygen species (mtROS) production, was elevated under hypoxic conditions in human and mouse portal hypertensive gastric mucosa and GC tissues. While blocking HIF-1α with PX-478, inhibiting Drp1-dependent mitochondrial fission via mitochondrial division inhibitor 1 (Mdivi-1) treatment or METTL3 mutation alleviated this process. Furthermore, HIF-1α influenced energy metabolism by enhancing glycolysis via lactate dehydrogenase A. In addition, HIF-1α-induced Drp1-dependent mitochondrial fission also enhanced glycolysis. Drp1-dependent mitochondrial fission and enhanced glycolysis were associated with alterations in antioxidant enzyme activity and dysfunction of the mitochondrial electron transport chain, resulting in massive mtROS production, which was needed for activation of NLRP3 inflammasome to aggravate the development of the PHG and GC. Under hypoxic conditions, HIF-1α enhances mitochondrial dysfunction via Drp1-dependent mitochondrial fission and influences the metabolic profile by altering glycolysis to increase mtROS production, which can trigger NLRP3 inflammasome activation and mucosal microenvironment alterations to contribute to the development of benign and malignant gastric mucosal lesions.

Construction of Magnolol Nanoparticles for Alleviation of Ethanol-Induced Acute Gastric Injury.

Ethanol (EtOH) has been identified as a potential pathogenic factor in gastric ulcer development primarily due to its association with gastric injury and excessive production of reactive oxygen species. Magnolol (Mag), the principal active compound in Magnolia officinalis extract, is well studied for its notable anti-inflammatory and antioxidant properties. However, its limited solubility, propensity for agglomeration, and low absorption and utilization rates significantly restrict its therapeutic use. This study aims to overcome these challenges by developing a Mag nanoparticle system targeting the treatment and prevention of EtOH-induced gastric ulcers in mice. Utilizing a click chemistry approach, we successfully synthesized this system by reacting thiolated bovine serum albumin (BSA·SH) with Mag. The in vitro analysis revealed effective uptake of the BSA·SH-Mag nanoparticle system by human gastric epithelial cells (GES-1), showcasing its antioxidant and anti-inflammatory capabilities. Additionally, BSA·SH-Mag exhibited gradual disintegration and release in simulated gastric fluid, resulting in a notable reduction of oxidative stress in gastric tissues and mucosal tissue repair and effectively reducing inflammatory expression. Furthermore, BSA·SH-Mag attenuated EtOH-induced gastric inflammation by decreasing the level of NOX4 protein expression and augmenting the level of Nrf2 protein expression. In conclusion, our findings indicate that BSA·SH-Mag represents a promising candidate as an oral therapeutic for gastric ulcer treatment.

Dark horse target Claudin18.2 opens new battlefield for pancreatic cancer.

Pancreatic cancer is one of the deadliest malignant tumors, which is a serious threat to human health and life, and it is expected that pancreatic cancer may be the second leading cause of cancer death in developed countries by 2030. Claudin18.2 is a tight junction protein expressed in normal gastric mucosal tissues, which is involved in the formation of tight junctions between cells and affects the permeability of paracellular cells. Claudin18.2 is highly expressed in pancreatic cancer and is associated with the initiation, progression, metastasis and prognosis of cancer, so it is considered a potential therapeutic target. Up to now, a number of clinical trials for Claudin18.2 are underway, including solid tumors such as pancreatic cancers and gastric cancers, and the results of these trials have not yet been officially announced. This manuscript briefly describes the Claudia protein, the dual roles of Cluadin18 in cancers, and summarizes the ongoing clinical trials targeting Claudin18.2 with a view to integrating the research progress of Claudin18.2 targeted therapy. In addition, this manuscript introduces the clinical research progress of Claudin18.2 positive pancreatic cancer, including monoclonal antibodies, bispecific antibodies, antibody-drug conjugates, CAR-T cell therapy, and hope to provide feasible ideas for the clinical treatment of Claudin18.2 positive pancreatic cancer.

Investigating Associations between HLA-DR Genotype, H. pylori Infection, and Anti-CagA IgA Seropositivity in a Turkish Gastritis Cohort.

Helicobacter pylori (H. pylori) is associated with gastric inflammation and mucosal antibodies against its cytotoxin-associated gene A (CagA) are protective. Vaccine-elicited immunity against H. pylori requires MHC class II expression, indicating that CD4+ T cells are protective. We hypothesized that the HLA-DR genotypes in human populations include protective alleles that more effectively bind immunogenic CagA peptide fragments and susceptible alleles with an impaired capacity to present CagA peptides. We recruited patients (n = 170) admitted for gastroendoscopy procedures and performed high-resolution HLA-DRB1 typing. Serum anti-CagA IgA levels were analyzed by ELISA (23.2% positive) and H. pylori classified as positive or negative in gastric mucosal tissue slides (72.9% positive). Pearson Chi-square analysis revealed that H. pylori infection was significantly increased in DRB1*11:04-positive individuals (p = 0.027). Anti-CagA IgA was significantly decreased in DRB1*11:04 positive individuals (p = 0.041). In contrast, anti-CagA IgA was significantly increased in DRB1*03:01 positive individuals (p = 0.030). For these HLA-DRB1 alleles of interest, we utilized two in silico prediction methods to compare their capacity to present CagA peptides. Both methods predicted increased numbers of peptides for DRB1*03:01 than DRB1*11:04. In addition, both alleles preferred distinctively different CagA 15mer peptide sequences for high affinity binding. These observations suggest that DRB1*11:04 is a susceptible genotype with impaired CagA immunity, whereas DRB1*03:01 is a protective genotype that promotes enhanced CagA immunity.

Abstract B036: Mutational landscape and genetic feature of gastric adenocarcinoma in multiple Chinese ethnicities

Abstract Gastric cancer is a heterogeneous malignancy and the fifth most common cancer worldwide, with 44% of cases occurring in China. Elucidation of genetic subtypes may improve gastric cancer treatment planning. Matched tumour and peritumoural (non-malignant gastric mucosa) tissue samples were collected from 306 Chinese patients and subjected to whole-exome sequencing (WES). The results were used to produce a Chinese Gastric Cancer Genome Atlas (CGCGA). Patients from nine Chinese ethnic groups (Han, Zhuang, Hui, Uygur, Yi, Tibetan, Mongolian, Bai, and Kazakh), representing 95% of the Chinese population were included. Systematic comparison of CGCGA data with TCGA (The Cancer Genome Atlas) data, in which 437 gastric cancer cases are represented, showed that genomic alteration signatures in the present cohort differed markedly from those reported for Western cohorts. TP53 and FAT1 deletions were more frequent (35% vs. 0%) while ARID1A deletions (13% vs. 25%), MYC oncogene amplifications (53% vs. 70%), and SMAD4 deletions (34% vs. 46%) were less frequent in our CGCGA data than in the TCGA data. TRIM49B mutation was associated with worse survival. Thus, TRIM49B was identified as a novel oncogene. The Zhuang ethnic group had a much higher tumour mutation burden (TMB) than the other ethnic groups. Typically, tumours from Han group had microsatellite stability, whereas those from the other groups had microsatellite instability (MSI). We further propose a molecular classification of four gastric cancer subtypes that are associated with distinct survival outcomes: TP53 mutation positive (TP53+)/TTN_missense+; TP53+/TTN_missense–; TP53–/TTN_missense+, and TP53–/TTN_missense–. Our study established a comprehensive gastric cancer genome atlas in China and underscored the importance of considering population context in genomic mapping and rational treatment options for the disease. Citation Format: Liang Zong. Mutational landscape and genetic feature of gastric adenocarcinoma in multiple Chinese ethnicities [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Translating Cancer Evolution and Data Science: The Next Frontier; 2023 Dec 3-6; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_2):Abstract nr B036.

Meckel’s diverticulum mimicking acute appendicitis in children: a retrospective cohort study

BackgroundThe aims of this study were to summarize the clinical presentation and histological results of 20 cases of complicated Meckel diverticulum (MD) who were presumed to have acute appendicitis before surgery, as well as to improve the diagnosis and treatment of complicated MD in children.Materials and methodsWe retrospectively reviewed the records of 20 complicated MD admitted to our institution who were preoperatively diagnosed with acute appendicitis from January 2012 to January 2019. Patients were divided into the perforated MD group and the Meckel’s diverticulitis group. Patient demographics, clinical manifestations, laboratory data, auxiliary examinations, surgical methods, and the result of heterotopic tissue were recorded.ResultsA total of 20 cases of complicated MD (perforated or diverticulitis) were identified. Children were aged from 3 to 13 years, with a mean age of 7.75 years (median 7.75; range, 1–13 years). Perforated Meckel’s diverticulum occurred in 5 of 20 (25%) cases. For perforated MD versus diverticulitis, no significant differences were found between age, time to intervention, length of hospital stay, and distance from the ileo-cecal valve. Heterotopic tissue was confirmed on histopathology in 75% of all patients, including 10 cases of gastric mucosa, 3 cases of coexistent gastric mucosa and pancreatic tissue, and 2 cases of pancreatic tissue. All patients underwent diverticulectomy or partial ileal resection under laparoscopy or laparotomy; two cases combined with appendectomy owing to slight inflammation of the appendix.ConclusionsThe most common presentation of symptomatic MD is painless rectal bleeding; however, it can present symptoms of acute abdomen mimicking acute appendicitis. The key point of diverticulectomy is to remove the ectopic mucosa completely.

Dysbiosis in gastric mucosal microbiota associated with gastric carcinogenesis.

381 Background: Gastric microbiota, including H. pylori, may play a role in the development of gastric cancer. This study aimed to investigate the gastric microbiota throughout the stages of gastric carcinogenesis, encompassing atrophic gastritis, gastric dysplasia, and gastric adenocarcinoma. Methods: From December 2021 to August 2023, we collected gastric mucosal tissue samples from patients with atrophic gastritis, gastric dysplasia, and early gastric cancer. Subsequently, we conducted 16S rRNA gene profiling through next-generation sequencing. We compared alpha-diversity and beta-diversity within each group and analyzed the taxonomic composition. Results: This study included a total of 98 patients, comprising 16 with atrophic gastritis, 23 with low-grade dysplasia, 15 with high-grade dysplasia, and 44 with early gastric cancer. The H. pylori infection status was comparable across all groups. While there was a difference in alpha diversity between tumor lesions and normal stomach lesions, it did not reach statistical significance. Notably, Phyllobacterium was dominant in early gastric cancer, Prevotella in high-grade dysplasia, and Kocura in low-grade dysplasia. Furthermore, within the early gastric cancer group, Bacillus was widely distributed in cases of undifferentiated type adenocarcinoma. Conclusions: The analysis of microbiota collected from Korean stomach tissue revealed distinct microbial distributions across the various stages of gastric carcinogenesis.

IL-33 Accelerates Chronic Atrophic Gastritis through AMPK-ULK1 Axis Mediated Autolysosomal Degradation of GKN1.

Chronic atrophic gastritis (CAG) is a complex disease characterized by atrophy and inflammation in gastric mucosal tissue, especially with high expression of interleukins. However, the interaction and mechanisms between interleukins and gastric mucosal epithelial cells in CAG remain largely elusive. Here, we elucidate that IL-33 stands out as the predominant inflammatory factor in CAG, and its expression is induced by H. pylori and MNNG through the ROS-STAT3 signaling pathway. Furthermore, our findings reveal that the IL-33/ST2 axis is intricately involved in the progression of CAG. Utilizing phosphoproteomics mass spectrometry, we demonstrate that IL-33 enhances autophagy in gastric epithelial cells through the phosphorylation of AMPK-ULK1 axis. Notably, inhibiting autophagy alleviates CAG severity, while augmentation of autophagy exacerbates the disease. Additionally, ROS scavenging emerges as a promising strategy to ameliorate CAG by reducing IL-33 expression and inhibiting autophagy. Intriguingly, IL-33 stimulation promotes GKN1 degradation through the autolysosomal pathway. Clinically, the combined measurement of IL-33 and GKN1 in serum shows potential as diagnostic markers. Our findings unveil an IL-33-AMPK-ULK1 regulatory mechanism governing GKN1 protein stability in CAG, presenting potential therapeutic targets for its treatment.

Mucosal Immunity Related to CD8+ T Lymphocytes in Children with Helicobacter pylori Gastritis.

We investigated the role of CD8+T cells as host immune factors in pediatric patients with Helicobacter pylori gastritis. Gastric mucosal tissue and blood samples were collected from 39 children, including 11 children with H. pylori infection and 28 children as controls. Anti-CD8 and anti-T-bet antibodies were used for immunohistochemistry of the gastric mucosa. For the cell surface and intracellular staining, peripheral blood mononuclear cells were stained with anti-IL7Rα, anti-CX3CR1, anti-CD8, anti-T-bet, and anti-IFN-γ antibodies. Cytokines of sera such as tumor necrosis factor alpha (TNF-α) and CX3CL1 were analyzed using enzyme- linked immunosorbent assay (ELISA). In the immunohistochemistry of gastric mucosa, the frequency of CD8+ and T-bet+ T cells cells was higher in the H. pylori-positive group than in the control group (26.9± 7.8% vs. 16.9±3.3%, p<0.001; 5.0±2.5% vs. 2.2±0.7%, p=0.001). Between the control and H. pylori-positive groups, the frequency of IL-7RαlowCX3CR1+ CD8+ and T-bet+ INF-γ+ CD8+ T cells were not significantly different between surface and intracellular staining, respectively (40.4±24.0% vs. 38.2±17.8%, p=0.914; 40.4±24.0% vs. 38.2±17.8%, p=0.914). In the ELISA, no significant differences in TNF-α and CX3CL1 concentrations were observed between the control and H. pylori-positive groups (34.3±12.1 pg/mL vs. 47.0±22.6 pg/mL, p=0.114/0.5± 0.1 pg/mL vs. 0.5±0.1 pg/mL, p=0.188). CD8+ T and Th1 cells, which secrete IFN-γ, might play important roles in the mucosal immunity of the stomach in children with H. pylori infection.

Investigating associations between HLA DQA1 ~ DQB1 haplotypes, H. pylori infection, metaplasia, and anti-CagA IgA seropositivity in a Turkish gastritis cohort.

Helicobacter pylori was reported as an important cause of gastritis, and gastric ulcers and CagA oncoprotein-producing H. pylori subgroups were blamed to increase the severity of gastritis. Disparities were reported in that the presence of serum anti-CagA IgA was not parallel with CagA-positive H. pylori cohabitation. We hypothesized that the HLA-DQA1 ~ DQB1 haplotypes in human populations include protective haplotypes that more effectively present immunogenic CagA peptides and susceptible haplotypes with an impaired capacity to present CagA peptides. We recruited patients (n = 201) admitted for gastroendoscopy procedures and performed high-resolution HLA-DQA1 and DQB1 typing. Serum anti-CagA IgA levels were analyzed by ELISA (23.0% positive), and H. pylori was classified as positive or negative in gastric mucosal tissue slides (72.6% positive). The HLA DQA1*05:05 allele (29.1%) and HLA DQB1*03:01 allele (32.8%) were found at the highest frequency among gastritis patients of Turkish descent. In HLA DQA1*05:05 ~ DQB1*03:01 double homozygous (7.3%) and heterozygous (40.7%) haplotype carriers, the presence of anti-CagA IgA decreased dramatically, the presence of H. pylori increased, and the presence of metaplasia followed a decreasing trend. The DQ protein encoded by HLA DQA1*05:05-DQ*03:01 showed a low binding affinity to the CagA peptide when binding capacity was analyzed by the NetMHCIIPan 4.0 prediction method. In conclusion, HLA DQA1 ~ DQB1 polymorphisms are crucial as host defense mechanisms against CagA H. pylori since antigen binding capacity plays a crucial role in anti-CagA IgA production.

Effect of IL-10-producing B cells in peripheral blood and tumor tissue on gastric cancer

BackgroundInterleukin (IL)-10-producing B (B10) cells are generated in response to signals from the tumor microenvironment and promote tumor growth by interacting with B10 cells. We investigated the distributions of immune cells in peripheral blood and tumor tissue samples from patients with gastric cancer (GC).MethodsPatients with GC who underwent radical gastrectomy in Seoul St. Mary’s Hospital between August 2020 and May 2021 were enrolled in this study. Forty-two samples of peripheral blood were collected, and a pair of gastric mucosal samples (normal and cancerous mucosa; did not influence tumor diagnosis or staging) was collected from each patient after surgery. B10 cells in peripheral blood and cancer mucosa samples were investigated by flow cytometry and immunofluorescence. AGS cells, gastric cancer cell line, were cultured with IL-10 and measured cell death and cytokine secretion. Also, AGS cells were co-cultured with CD19 + B cells and measured cytokine secretion.ResultsThe population of B10 cells was significantly larger in the blood of patients with GC compared with controls. In confocal images of gastric mucosal tissues, cancerous mucosa contained more B10 cells than normal mucosa. The population of B10 cells in cancerous mucosa increased with cancer stage. When AGS cells were cultured under cell-death conditions, cellular necrosis was significantly decreased, and proliferation was increased, for 1 day after IL-10 stimulation. Tumor necrosis factor (TNF)-α, IL-8, IL-1β, and vascular endothelial growth factor secretion by cancer cells was significantly increased by coculture of AGS cells with GC-derived CD19+ B cells.ConclusionsB cells may be one of the populations that promote carcinogenesis by inducing the production of inflammatory mediators, such as IL-10, in GC. Targeting B10 cells activity could improve the outcomes of antitumor immunotherapy.DziBRYVf4qaf1RtDpaCYhWVideo