Normal Stomach Research Articles

385. TRANSLATING MOLECULAR-TARGETING FLUORESCENT PROBES IN OESOPHAGEAL CANCER PRE-CLINICAL MODELS

Abstract Background Intra-operative molecular imaging (IMI) is an emerging field that utilises tumour-targeting fluorescent probes to improve oncological outcomes. A novel class of probe known as quenched activity-based probes (qABP), developed to measure enzyme activity in-vitro, has been repurposed to target tumour-expressed proteases known as cathepsins. Unlike other tumour-targeting probes, fluorescence is inhibited up until the qABP covalently bonds to cathepsins, releasing an inhibitory quencher which results in fluorescence. This may improve the contrast between normal tissue and tumour. Our laboratory group sought to obtain pre-clinical evidence to eventually translate qABP’s into the operating room for oesophageal, junctional and gastric cancer. Methods Cathepsin activity was screened in cell lines from the normal oesophagus, Barrett’s metaplasia, oesophageal adenocarcinoma (OAC), squamous cell carcinoma (SCC) and gastric adenocarcinoma (GAC) with two qABP’s known as BMV109 and VGT309. We additionally screened patient biopsies from oesophageal, junctional and gastric cancers. Cell line and tissue samples were analysed using in-gel fluorescence (Amersham Typhoon®) and Western blot. In-vivo, cell line xenografts were established in NSG mice using subcutaneous and orthotopic models. Tumour-bearing mice were then injected with VGT-309 and then imaged at specific timepoints using the IVIS® spectrum imager. Results Cathepsin activity was found in all oesophago-gastric cell lines and selectivity proven with a cathepsin inhibitor. Matched biopsies were collected from patients prior before and after neoadjuvant chemo-radiotherapy. Baseline tumour biopsies exhibited significantly higher cathepsin activity than normal biopsies, with these differences preserved in biopsies collected after chemo-radiotherapy (p <0.001). In-vivo, OAC and GAC xenografts were identified in NSG mice as early as 12 hours post injection of VGT-309, exhibiting a 2.5-fold increase in fluorescence compared to normal background stomach. Bio-distribution analysis demonstrated that VGT-309 accumulated in liver and kidney, but less so in the murine oesophagus and stomach. Conclusion Translating qABP’s into the operating room has the potential to detect early cancers in Barrett’s metaplasia, reduce positive margin rates and identify lymph node metastasis. Our research group continues to investigate qABP’s, including determining their sensitivity to detect lymph node metastasis with the aim of translating this technology into a phase 1 clinical trial.

Phase-contrast visualization of human tissues using superimposed wavefront imaging of diffraction-enhanced x-rays.

Phase-contrast computed tomography (CT) using high-brilliance, synchrotron-generated x-rays enable three-dimensional (3D) visualization of microanatomical structures within biological specimens, offering exceptionally high-contrast images of soft tissues. Traditional methods for phase-contrast CT; however, necessitate a gap between the subject and the x-ray camera, compromising spatial resolution due to penumbral blurring. Our newly developed technique, Superimposed Wavefront Imaging of Diffraction-enhanced x-rays (SWIDeX), leverages a Laue-case Si angle analyzer affixed to a scintillator to convert x-rays to visible light, capturing second-order differential phase contrast images and effectively eliminating the distance to the x-ray camera. This innovation achieves superior spatial resolution over conventional methods. In this paper, the imaging principle and CT reconstruction algorithm based on SWIDeX are presented in detail and compared with conventional analyzer-based imaging (ABI). It also shows the physical setup of SWIDeX that provides the resolution preserving second-order differential images for reconstruction. We compare the spatial resolution and the sensitivity of SWIDeX to conventional ABI. To demonstrate high-spatial resolution achievable by SWIDeX, the internal structures of four human tissues-ductal carcinoma in situ, normal stomach, normal pancreas, and intraductal papillary mucinous neoplasm of the pancreas-were visualized using an imaging system configured at the Photon Factory's BL14B beamline under the High Energy Accelerator Research Organization (KEK). Each tissue was thinly sliced after imaging, stained with hematoxylin and eosin (H&E) for conventional microscope-based pathology. A comparison of SWIDeX-CT and pathological images visually demonstrates the effectiveness of SWIDeX-CT for biological tissue imaging. SWIDeX could generate clearer 3D images than existing analyzer-based phase-contrast methods and accurately delineate tissue structures, as validated against histopathological images. SWIDeX can visualize important 3D structures in biological soft tissue with high spatial resolution and can be an important tool for providing information between the disparate scales of clinical and pathological imaging.

Cytotoxicity assessment of Cu0.5Zn0.5Fe2O4 nanoparticles prepared via rapid combustion-calcination process on SGC-7901 and HGC-27 gastric cancer cells

Currently, ferrite magnetic nanoparticles are widely utilized in the biomedical domain, encompassing antibacterial, catalytic, imaging, and drug delivery among other fields. In this study, Cu0.5Zn0.5Fe2O4 nanoparticles were synthesized via the rapid combustion-calcination process. By incorporating inorganic metal elements with specific functionalities, the limitations of iron oxide could be overcome, enabling targeted roles in various applications. The morphology, phase composition, and magnetic properties were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). The impact of anhydrous ethanol quantity, calcination temperature, and duration on the magnetic properties and grain size of the nanomaterials was investigated. Cu0.5Zn0.5Fe2O4 nanoparticles were evaluated for their inhibitory effects on human gastric cancer cells (SGC-7901 and HGC-27) under different preparation conditions. The results of the MTT assay revealed a concentration - and time-dependent inhibition of tumor cell proliferation by Cu0.5Zn0.5Fe2O4 nanoparticles. Nanoparticles exhibiting a magnetic energy of 20.23 emu/g and an average particle size of 51.6 nm, synthesized using 20 mL of anhydrous ethanol, calcination temperature of 400 °C, and a calcination duration of 2.0 h, displayed significant inhibitory effects on tumor cells. Furthermore, The nanoparticles not only showed low toxicity to human normal stomach cells GES-1, but also enhanced the inhibitory effect on tumor cells under the action of an external magnetic field.

Development of a Neopentyl 211At-Labeled Activated Ester Providing In Vivo Stable 211At-Labeled Antibodies for Targeted Alpha Therapy.

In this study we developed a neopentyl 211At-labeled activated ester that incorporates a triazole spacer and applied it to the synthesis of an 211At-labeled cetuximab. The activated ester was synthesized via the nucleophilic 211At-astatination of a neopentyl sulfonate carrying two long alkyl chains that serve as a lipid tag, which was followed by the hydrolysis of an acetal. Additionally, we developed a novel Resin-Assisted Purification and Deprotection (RAPD) protocol involving a solid-phase extraction of the protected 211At-labeled compound from the mixture of the labeling reaction, hydrolysis of the acetal on the resin, and finally an elution of the 211At-labeled activator from the resin. This method allows the synthesis of an 211At-labeled activated ester with high purity through a simplified procedure that circumvents the need for HPLC purification. Using this 211At-labeled activated ester, we efficiently synthesized 211At-labeled cetuximab in 27±1 % radiochemical yield with 95 % radiochemical purity. This 211At-activated ester demonstrated high reactivity, and enabled the completion of the reaction with the antibody within 10 min. In comparative biodistribution studies between 211At-labeled cetuximab and the corresponding 125I-labeled cetuximab in normal mice, both the thyroid and stomach showed radioactivity levels that were less than 1.0 % of the injected dose.

Establishment of a Novel Cancer-Specific Anti-HER2 Monoclonal Antibody H2Mab-250/H2CasMab-2 for Breast Cancers.

Overexpression of human epidermal growth factor receptor 2 (HER2) in breast and gastric cancers is an important target for monoclonal antibody (mAb) therapy. All therapeutic mAbs, including anti-HER2 mAbs, exhibit adverse effects probably due to the recognition of antigens expressed in normal cells. Therefore, tumor-selective or specific mAbs can be beneficial in reducing the adverse effects. In this study, we established a novel cancer-specific anti-HER2 monoclonal antibody, named H2Mab-250/H2CasMab-2 (IgG1, kappa). H2Mab-250 reacted with HER2-positive breast cancer BT-474 and SK-BR-3 cells. Importantly, H2Mab-250 did not react with nontransformed normal epithelial cells (HaCaT and MCF 10A) and immortalized normal epithelial cells in flow cytometry. In contrast, most anti-HER2 mAbs, such as H2Mab-119 and trastuzumab reacted with both cancer and normal epithelial cells. Immunohistochemical analysis demonstrated that H2Mab-250 possesses much higher reactivity to the HER2-positive breast cancer tissues compared with H2Mab-119, and did not react with normal tissues, including heart, breast, stomach, lung, colon, kidney, and esophagus. The epitope mapping demonstrated that the Trp614 of HER2 domain IV mainly contributes to the recognition by H2Mab-250. H2Mab-250 could contribute to the development of chimeric antigen receptor-T or antibody-drug conjugates without adverse effects for breast cancer therapy.

Abstract 5583: Helicobacter pylori induces the wee1, promoting immune suppressive in human gastric adenocarcinoma

Abstract Background: Gastric cancer (GC) is the fourth most common cause of cancer-related death worldwide. GC has a dismal 5-year survival rate of about 32%. Helicobacter pylori (H. pylori) infection is the strongest risk factor for gastric carcinogenesis. 75-90% of gastric cancer patients exhibit positive H. pylori serology. WEE1 is a nuclear kinase that regulates cell cycle progression by inhibiting cyclin-dependent kinases. Methods & Results: Analysis of non-cancer normal stomach tissue (n=360) and human GC samples (n=1221) identified that WEE1 mRNA was significantly overexpressed in GC. Using immunohistochemistry (IHC) staining in 41 normal and 44 GC human samples, the data indicated that WEE1 protein was significantly overexpressed in GC. Western blot and immunofluorescence (IF) staining confirmed that H. pylori infection induces WEE1 overexpression in GC cells with an unexpected cytosolic localization of WEE1 in GC cells. Tff1 knockout GC mouse model (Tff1-/-) was infected with mouse-adapted H. pylori strain PMSS1. Western blot and immunohistochemistry data demonstrated that H. pylori infection induced WEE1 expression in Tff1 -/- HGD/cancer mouse gastric tissues compared to control Tff1 -/- mouse stomach. To study how H. pylori infection induces WEE1 in GC, analysis from miRTAR, Target Scan, and miRDB demonstrated that WEE1 is predicted to be targeted by miR-497-5p. Using qRT-PCR analysis, we assessed 30 normal and 30 GC human tissue samples, revealing a pronounced downregulation of miR-497-5p in GC specimens. Western blot analysis confirmed that the restoration of miR-497-5p in GC cells markedly reduced WEE1 protein expression. Interestingly, H. pylori infection further decreased miR-497-5p levels in GC cells, upregulating WEE1 protein expression. Since the miR-497-5P host gene promoter region contains CpG islands, we confirmed that treatment with 5 Azacytidine (demethylating agent) or DNMT1 knockdown induced expression of miR-497-5p with decreased WEE1 level in GC cells. Furthermore, our preliminary results indicate that aberrant WEE1 overexpression in GC demonstrates a significant positive correlation with immune-suppression gene signatures, underscoring its predictive value for unfavorable patient survival outcomes in GC. Using the TFF1 knockout mouse GC model, we found that WEE1 inhibition notably decreases the number and activation of CD4+ and CD8+ T cells in neoplastic gastric tissues. These findings also indicate a crucial relationship between WEE1 and the immunosuppressive microenvironment in GC, establishing WEE1 as a promising therapeutic target to enhance therapeutic efficacy and overcome immunotherapy resistance in GC. Conclusions: Our findings demonstrated a novel mechanism in which H. pylori activates the WEE1 in GC, promoting an immune suppressive microenvironment. WEE1 inhibition with immunotherapy could be a promising therapeutic method for GC patients. Citation Format: Md Obaidul Islam, Krishnapriya Thangaretnam, Heng Lu, Dunfa Peng, Nadeem Sidiq Bhat, Mohammed Soutto, Wael El-Rifai, Zheng Chen. Helicobacter pylori induces the wee1, promoting immune suppressive in human gastric adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5583.

Abstract 3034: Krüppel-like factors in regulation of gastric cancer progression

Abstract Introduction: Gastric cancer (GC) is the third leading cause of cancer-associated mortality and the fifth most frequently diagnosed cancer worldwide. The development and progression of GC is a complicated multistage process subjected to dynamic changes in gene regulation. Investigating the effects of these changes is therefore critical for improving our knowledge about GC initiation and progression. Krüppel-like factors (KLFs) are evolutionarily conserved zinc finger-containing transcription factors with altered expressions and diverse regulatory functions in GC. We previously reported that there is loss of KLF4 in GC. Here we report that KLF4 is a crucial regulator of KLF5 expression and vice versa and together they regulate GC cell behavior. Methods: The Cancer Genome Atlas (TCGA) and pan cancer data of differential expressions of KLFs in GC was analyzed. TCGA RNAseq and clinical data for the differential expression status of KLF genes in normal and cancerous tissues and the clinicopathological association was accessed from the UALCAN web portal. The expressions of KLF4 and KLF5 in human normal stomach and GC and orthotopic xenografts were detected by immunohistochemistry (IHC). KLF4, KLF5 cross regulation was evaluated by gene manipulation of each gene individually and checking the expression of the other factor in GC cells. The effect of KLFs on GC cell proliferation, migration, and invasion was determined by Ki67 staining of tissues, PrestoBlue cell viability assay, scratch wound and transwell cell invasion assays. Results and Conclusion: Our results indicated that not only KLF4 and KLF5 have contrasting expressions and effects in GC but also these two factors cross regulate each other. While lower expressions of KLF4 was found in human GC and orthotopic xenografts, increased expression of KLF5 was found in both human GC tissue and orthotopic xenografts. KLF4 silencing and CRISPR/Cas9 knockdown in human GC cells resulted in increased expression of KLF5 which was associated with increased GC cell proliferation and invasiveness. Interestingly, KLF5 knockdown by CRISPR/Cas9 in human GC cells on the other hand resulted in increased expression of KLF4, which was associated with decreased GC cell growth. Our data therefore suggests that the differential expressions of KLF4 and KLF5 might serve as valuable prognostic markers in GC. Citation Format: Sooraj Kakkat, Prabhat Suman, Sandeep Goswami, Sujit Basu, Martin J. Heslin, Elba A. Turbat-Herrera, Veronica Ramirez Alcantara, Chandrani Sarkar, Debanjan Chakroborty. Krüppel-like factors in regulation of gastric cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3034.

Tubulointerstitial nephritis antigen-like 1 from cancer-associated fibroblasts contribute to the progression of diffuse-type gastric cancers through the interaction with integrin β1

BackgroundTumor cells of diffuse-type gastric cancer (DGC) are discohesive and infiltrate into the stroma as single cells or small subgroups, so the stroma significantly impacts DGC progression. Cancer-associated fibroblasts (CAFs) are major components of the tumor stroma. Here, we identified CAF-specific secreted molecules and investigated the mechanism underlying CAF-induced DGC progression.MethodsWe conducted transcriptome analysis for paired normal fibroblast (NF)-CAF isolated from DGC patient tissues and proteomics for conditioned media (CM) of fibroblasts. The effects of fibroblasts on cancer cells were examined by transwell migration and soft agar assays, western blotting, and in vivo. We confirmed the effect of blocking tubulointerstitial nephritis antigen-like 1 (TINAGL1) in CAFs using siRNA or shRNA. We evaluated the expression of TINAGL1 protein in frozen tissues of DGC and paired normal stomach and mRNA in formalin-fixed, paraffin-embedded (FFPE) tissue using RNA in-situ hybridization (RNA-ISH).ResultsCAFs more highly expressed TINAGL1 than NFs. The co-culture of CAFs increased migration and tumorigenesis of DGC. Moreover, CAFs enhanced the phosphorylation of focal adhesion kinase (FAK) and mesenchymal marker expression in DGC cells. In an animal study, DGC tumors co-injected with CAFs showed aggressive phenotypes, including lymph node metastasis. However, increased phosphorylation of FAK and migration were reduced by blocking TINAGL1 in CAFs. In the tissues of DGC patients, TINAGL1 was higher in cancer than paired normal tissues and detected with collagen type I alpha 1 chain (COL1A1) in the same spot. Furthermore, high TINAGL1 expression was significantly correlated with poor prognosis in several public databases and our patient cohort diagnosed with DGC.ConclusionsThese results indicate that TINAGL1 secreted by CAFs induces phosphorylation of FAK in DGC cells and promotes tumor progression. Thus, targeting TINAGL1 in CAFs can be a novel therapeutic strategy for DGC.

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.

Asialoglycoprotein Receptor 2 Expression in Patients With Locally Advanced Gastric Cancer After Curative Resection.

The asialoglycoprotein receptor 2 gene (ASGR2) encodes a subunit of the asialoglycoprotein receptor, a transmembrane protein, which has recently been reported to be involved in gastric cancer (GC) progression. This study aimed to investigate the clinical significance of ASGR2 expression in GC tissues of patients with locally advanced gastric cancer (LAGC) after curative resection. ASGR2 expression was measured in GC tissues and adjacent normal gastric mucosa in 253 patients with pStage II/III GC who underwent curative resection, by using quantitative polymerase chain reaction. We compared the expression levels in GC tissues and adjacent normal stomach mucosa, and evaluated the relationship of its expression in GC tissues with clinicopathological factors and overall survival (OS). ASGR2 expression was significantly associated with lymph node metastasis and venous invasion. The high ASGR2-expression group demonstrated significantly lower survival than the low expression group (5-year survival 55.5% vs. 72.6%; p=0.009). Furthermore, in multivariate analysis, high ASGR2 expression was an independent factor for poor OS (hazard ratio=2.030; 95% confidence interval=1.318-3.127; p=0.001). ASGR2 expression in GC tissues may be a useful prognostic marker in patients with LAGC after curative resection.

Dynamic tuft cell expansion during gastric metaplasia and dysplasia.

Tuft cells are chemosensory cells associated with luminal homeostasis, immune response, and tumorigenesis in the gastrointestinal tract. We aimed to elucidate alterations in tuft cell populations during gastric atrophy and tumorigenesis in humans with correlative comparison to relevant mouse models. Tuft cell distribution was determined in human stomachs from organ donors and in gastric pathologies including Ménétrier's disease, Helicobacter pylori gastritis, intestinal metaplasia (IM), and gastric tumors. Tuft cell populations were examined in Lrig1-KrasG12D , Mist1-KrasG12D , and MT-TGFα mice. Tuft cells were evenly distributed throughout the entire normal human stomach, primarily concentrated in the isthmal region in the fundus. Ménétrier's disease stomach showed increased tuft cells. Similarly, Lrig1-Kras mice and mice overexpressing TGFα showed marked foveolar hyperplasia and expanded tuft cell populations. Human stomach with IM or dysplasia also showed increased tuft cell numbers. Similarly, Mist1-Kras mice had increased numbers of tuft cells during metaplasia and dysplasia development. In human gastric cancers, tuft cells were rarely observed, but showed positive associations with well-differentiated lesions. In mouse gastric cancer xenografts, tuft cells were restricted to dysplastic well-differentiated mucinous cysts and were lost in less differentiated cancers. Taken together, tuft cell populations increased in atrophic human gastric pathologies, metaplasia, and dysplasia, but were decreased in gastric cancers. Similar findings were observed in mouse models, suggesting that, while tuft cells are associated with precancerous pathologies, their loss is most associated with the progression to invasive cancer.

Remodeling of the gastric environment in Helicobacter pylori-induced atrophic gastritis.

Helicobacter pylori colonization of the human stomach is a strong risk factor for gastric cancer. To investigate H. pylori-induced gastric molecular alterations, we used a Mongolian gerbil model of gastric carcinogenesis. Histologic evaluation revealed varying levels of atrophic gastritis (a premalignant condition characterized by parietal and chief cell loss) in H. pylori-infected animals, and transcriptional profiling revealed a loss of markers for these cell types. We then assessed the spatial distribution and relative abundance of proteins in the gastric tissues using imaging mass spectrometry and liquid chromatography with tandem mass spectrometry. We detected striking differences in the protein content of corpus and antrum tissues. Four hundred ninety-two proteins were preferentially localized to the corpus in uninfected animals. The abundance of 91 of these proteins was reduced in H. pylori-infected corpus tissues exhibiting atrophic gastritis compared with infected corpus tissues exhibiting non-atrophic gastritis or uninfected corpus tissues; these included numerous proteins with metabolic functions. Fifty proteins localized to the corpus in uninfected animals were diffusely delocalized throughout the stomach in infected tissues with atrophic gastritis; these included numerous proteins with roles in protein processing. The corresponding alterations were not detected in animals infected with a H. pylori ∆cagT mutant (lacking Cag type IV secretion system activity). These results indicate that H. pylori can cause loss of proteins normally localized to the gastric corpus as well as diffuse delocalization of corpus-specific proteins, resulting in marked changes in the normal gastric molecular partitioning into distinct corpus and antrum regions.IMPORTANCEA normal stomach is organized into distinct regions known as the corpus and antrum, which have different functions, cell types, and gland architectures. Previous studies have primarily used histologic methods to differentiate these regions and detect H. pylori-induced alterations leading to stomach cancer. In this study, we investigated H. pylori-induced gastric molecular alterations in a Mongolian gerbil model of carcinogenesis. We report the detection of numerous proteins that are preferentially localized to the gastric corpus but not the antrum in a normal stomach. We show that stomachs with H. pylori-induced atrophic gastritis (a precancerous condition characterized by the loss of specialized cell types) exhibit marked changes in the abundance and localization of proteins normally localized to the gastric corpus. These results provide new insights into H. pylori-induced gastric molecular alterations that are associated with the development of stomach cancer.

Marked intestinal trans-differentiation by autoimmune gastritis along with ectopic pancreatic and pulmonary trans-differentiation

BackgroundAutoimmune gastritis (AIG) is a prevalent chronic inflammatory disease with oncogenic potential that causes destruction of parietal cells and severe mucosal atrophy. We aimed to explore the distinctive gene expression profiles, activated signaling pathways, and their underlying mechanisms.MethodsA comprehensive gene expression analysis was conducted using biopsy specimens from AIG, Helicobacter pylori-associated gastritis (HPG), and non-inflammatory normal stomachs. Gastric cancer cell lines were cultured under acidic (pH 6.5) conditions to evaluate changes in gene expression.ResultsGastric mucosa with AIG had a unique gene expression profile compared with that with HPG and normal mucosa, such as extensively low expression of ATP4A and high expression of GAST and PAPPA2, which are involved in neuroendocrine tumorigenesis. Additionally, the mucosa with AIG and HPG showed the downregulation of stomach-specific genes and upregulation of small intestine-specific genes; however, intestinal trans-differentiation was much more prominent in AIG samples, likely in a CDX-dependent manner. Furthermore, AIG induced ectopic expression of pancreatic digestion-related genes, PNLIP, CEL, CTRB1, and CTRC; and a master regulator gene of the lung, NKX2-1/TTF1 with alveolar fluid secretion-related genes, SFTPB and SFTPC. Mechanistically, acidic conditions led to the downregulation of master regulator and stemness control genes of small intestine, suggesting that increased environmental pH may cause abnormal intestinal differentiation in the stomach.ConclusionsAIG induces diverse trans-differentiation in the gastric mucosa, characterized by the transactivation of genes specific to the small intestine, pancreas, and lung. Increased environmental pH owing to AIG may cause abnormal differentiation of the gastric mucosa.

Long non-coding RNA NRAV in the 12q24.31 risk locus drives gastric cancer development through glucose metabolism reprogramming.

Long non-coding RNAs (lncRNAs) serve as vital candidates to mediate cancer risk. Here, we aimed to identify the risk single-nucleotide polymorphisms (SNPs)-induced lncRNAs and to investigate their roles in gastric cancer (GC) development. Through integrating the differential expression analysis of lncRNAs in GC tissues and expression quantitative trait loci analysis in normal stomach tissues and GC tissues, as well as genetic association analysis based on GC genome-wide association studies and an independent validation study, we identified four lncRNA-related SNPs consistently associated with GC risk, including SNHG7 [odds ratio (OR) = 1.16, 95% confidence interval (CI): 1.09-1.23], NRAV (OR = 1.11, 95% CI: 1.05-1.17), LINC01082 (OR = 1.16, 95% CI: 1.08-1.22) and FENDRR (OR = 1.16, 95% CI: 1.07-1.25). We further found that a functional SNP rs6489786 at 12q24.31 increases binding of MEOX1 or MEOX2 at a distal enhancer and results in up-regulation of NRAV. The functional assays revealed that NRAV accelerates GC cell proliferation while inhibits GC cell apoptosis. Mechanistically, NRAV decreases the expression of key subunit genes through the electron transport chain, thereby driving the glucose metabolism reprogramming from aerobic respiration to glycolysis. These findings suggest that regulating lncRNA expression is a crucial mechanism for risk-associated variants in promoting GC development.

Elevated expression of Axin2 in intestinal metaplasia and gastric cancers.

The Wnt signaling pathway regulates crucial cellular processes, including stem cell development and tissue repair. Dysregulation of this pathway, particularly β-catenin stabilization, is linked to colorectal carcinoma and other tumors. Axin2, a critical component in the pathway, plays a role in β-catenin regulation. This study examines Axin2 expression in normal gastric mucosa and various gastric pathologies. Formalin-fixed and paraffin-embedded tissue samples from normal stomach, gastritis, intestinal metaplasia (IM), and gastric carcinoma were collected. Axin2 and β-catenin expression were evaluated using RNA in situ hybridization and immunohistochemistry, respectively. Histo-scores (H-scores) were calculated to quantify expression levels of Axin2. Associations between Axin2 expression and clinicopathological variables were examined. Axin2 expression was examined in normal stomach, gastritis, and IM tissues. Axin2 expression was mainly observed in the surface and isthmus areas in the normal stomach and gastritis, whereas Axin2 expression was markedly higher at the bases of IM. Axin2 H-scores were significantly elevated in IM (mean ± standard deviation [SD], 87.0 ± 38.9) compared to normal (mean ± SD, 18.0 ± 4.5) and gastritis tissues (mean ± SD, 33.0 ± 18.6). In total, 30% of gastric carcinomas showed higher Axin2 expression. Axin2 expression did not have significant associations with age, sex, Lauren classification, histological differentiation, invasion depth, and lymph node metastasis. However, a strong positive correlation was observed between Axin2 and nuclear β-catenin in gastric carcinomas (p < .001). Axin2 expression was significantly increased in IM compared to normal and gastritis cases. In addition, Axin2 showed a strong positive association with nuclear β-catenin expression in gastric carcinomas, demonstrating a close relationship with abnormal Wnt/β-catenin signaling pathway.

Multi-cancer analysis reveals universal association of oncogenic LBH expression with DNA hypomethylation and WNT-Integrin signaling pathways

Limb-Bud and Heart (LBH) is a developmental transcription co-factor deregulated in cancer, with reported oncogenic and tumor suppressive effects. However, LBH expression in most cancer types remains unknown, impeding understanding of its mechanistic function Here, we performed systematic bioinformatic and TMA analysis for LBH in >20 different cancer types. LBH was overexpressed in most cancers compared to normal tissues (>1.5-fold; p < 0.05), including colon-rectal, pancreatic, esophageal, liver, stomach, bladder, kidney, prostate, testicular, brain, head & neck cancers, and sarcoma, correlating with poor prognosis. The cancer types showing LBH downregulation were lung, melanoma, ovarian, cervical, and uterine cancer, while both LBH over- and under-expression were observed in hematopoietic malignancies. In cancers with LBH overexpression, the LBH locus was frequently hypomethylated, identifying DNA hypomethylation as a potential mechanism for LBH dysregulation. Pathway analysis identified a universal, prognostically significant correlation between LBH overexpression and the WNT-Integrin signaling pathways. Validation of the clinical association of LBH with WNT activation in gastrointestinal cancer cell lines, and in colorectal patient samples by IHC uncovered that LBH is specifically expressed in tumor cells with nuclear beta-catenin at the invasive front. Collectively, these data reveal a high degree of LBH dysregulation in cancer and establish LBH as pan-cancer biomarker for detecting WNT hyperactivation in clinical specimens.

3D Chromatin Architecture Re-Wiring at the CDH3/CDH1 Loci Contributes to E-Cadherin to P-Cadherin Expression Switch in Gastric Cancer.

Cadherins are cell-cell adhesion molecules, fundamental for cell architecture and polarity. E-cadherin to P-cadherin switch can rescue adherens junctions in epithelial tumours. Herein, we disclose a mechanism for E-cadherin to P-cadherin switch in gastric cancers. CDH1 and CDH3 mRNA expression was obtained from 42 gastric tumours' RNA-seq data. CRISPR-Cas9 was used to knock out CDH1 and a putative regulatory element. CDH1-depleted and parental cells were submitted to proteomics and enrichment GO terms analysis; ATAC-seq/4C-seq with a CDH1 promoter viewpoint to assess chromatin accessibility and conformation; and RT-PCR/flow cytometry to assess CDH1/E-cadherin and CDH3/P-cadherin expression. In 42% of gastric tumours analysed, CDH1 to CDH3 switch was observed. CDH1 knockout triggered CDH1/E-cadherin complete loss and CDH3/P-cadherin expression increase at plasma membrane. This switch, likely rescuing adherens junctions, increased cell migration/proliferation, commonly observed in aggressive tumours. E- to P-cadherin switch accompanied increased CDH1 promoter interactions with CDH3-eQTL, absent in normal stomach and parental cells. CDH3-eQTL deletion promotes CDH3/CDH1 reduced expression. These data provide evidence that loss of CDH1/E-cadherin expression alters the CDH3 locus chromatin conformation, allowing a CDH1 promoter interaction with a CDH3-eQTL, and promoting CDH3/P-cadherin expression. These data highlight a novel mechanism triggering E- to P-cadherin switch in gastric cancer.

Combined loss of CDH1 and downstream regulatory sequences drive early-onset diffuse gastric cancer and increase penetrance of hereditary diffuse gastric cancer

BackgroundGermline CDH1 pathogenic or likely pathogenic variants cause hereditary diffuse gastric cancer (HDGC). Once a genetic cause is identified, stomachs’ and breasts’ surveillance and/or prophylactic surgery is offered to asymptomatic CDH1 carriers, which is life-saving. Herein, we characterized an inherited mechanism responsible for extremely early-onset gastric cancer and atypical HDGC high penetrance.MethodsWhole-exome sequencing (WES) re-analysis was performed in an unsolved HDGC family. Accessible chromatin and CDH1 promoter interactors were evaluated in normal stomach by ATAC-seq and 4C-seq, and functional analysis was performed using CRISPR-Cas9, RNA-seq and pathway analysis.ResultsWe identified a germline heterozygous 23 Kb CDH1-TANGO6 deletion in a family with eight diffuse gastric cancers, six before age 30. Atypical HDGC high penetrance and young cancer-onset argued towards a role for the deleted region downstream of CDH1, which we proved to present accessible chromatin, and CDH1 promoter interactors in normal stomach. CRISPR-Cas9 edited cells mimicking the CDH1-TANGO6 deletion display the strongest CDH1 mRNA downregulation, more impacted adhesion-associated, type-I interferon immune-associated and oncogenic signalling pathways, compared to wild-type or CDH1-deleted cells. This finding solved an 18-year family odyssey and engaged carrier family members in a cancer prevention pathway of care.ConclusionIn this work, we demonstrated that regulatory elements lying down-stream of CDH1 are part of a chromatin network that control CDH1 expression and influence cell transcriptome and associated signalling pathways, likely explaining high disease penetrance and very young cancer-onset. This study highlights the importance of incorporating scientific–technological updates and clinical guidelines in routine diagnosis, given their impact in timely genetic diagnosis and disease prevention.Graphical abstract

Diagnostic performance of the normal range of gastrin calculated using strict criteria based on a combination of serum markers and pathological evaluation for detecting gastritis: a retrospective study

BackgroundThe ABC method, which combines the pepsinogen method and anti-Helicobacter pylori antibody titers, has been used for risk screening for gastric cancer in Japan. However, it has been reported that there are cases of gastritis and carcinogenesis risk even in group A, which is considered to be a low-risk group based on the ABC method. Currently, in group A, endoscopic examination is needed to strictly discriminate “patients without gastritis” (defined as true A patients) from those “with gastritis.” A simple and minimally invasive diagnostic criterion for gastritis using serological markers is desirable. In this study, we aimed to identify the normal serum gastrin concentrations in normal stomach cases based on pathological diagnosis and investigate the usefulness of serum gastrin concentrations in diagnosing gastritis.MethodsPatients who underwent endoscopy and blood tests at Hiroshima University Hospital were enrolled in the study and categorized into the “pathologically-evaluated group” and “endoscopically-evaluated group,” according to the evaluation method of atrophic gastritis. Initially, we measured serum gastrin concentrations in the normal stomach cases in the pathologically-evaluated group and calculated the normal range of serum gastrin concentrations. We used the upper limit of this normal range of serum gastrin concentrations and performed a validation study to determine its usefulness as a diagnostic marker for distinguishing between cases of gastritis and true A in the endoscopically-evaluated group.ResultsThe 95th percentile of serum gastrin concentrations in pathologically-evaluated normal stomach cases was 34.12–126.03 pg/mL. Using the upper limit of this normal range of serum gastrin concentrations, the sensitivity, specificity, positive predictive value, and negative predictive value for gastritis were 52.8%, 92.6%, 97.0%, and 31.0%, respectively. Additionally, the receiver operating characteristic (ROC) curve for the endoscopically-evaluated group showed an area under the ROC curve of 0.80.ConclusionThe gastrin cut-off value of 126 pg/mL has a good positive predictive value (97.0%) for detecting gastritis positing its use as a marker for cases requiring endoscopy. However, the identification of patients with gastritis having normal serum gastrin concentrations due to insufficient sensitivity remains a challenge for the future.

O095 hCNT (human concentrative nucleoside transporter) and hENT (human equilibrative nucleoside transporter) in human gastric cancer and response to chemotherapies

Abstract Introduction hCNT (Human Concentrative Nucleoside Transporter, also known as SLC28A1) and hENT (Human Equilibrative Nucleoside Transporter, SLC29A1) belong to the large solute carrier (SLC) family, a large membrane transport molecule group for the influx and efflux across cell membrane of various solutes including some of the anticancer drugs. hCNT and hENT are suggested to be involved in the transportation of certain chemotherapeutic drugs. The present study investigated the role of both transporters in gastric cancer and the response of gastric cancer cell and patients to chemotherapeutic drugs. Methods The expression levels of hCNT and hENT gene transcripts and proteins were determined in two independent gastric cancer cohorts and assessed against patient's responses to neoadjuvent chemotherapies. Their value in assessing patient's survival, clinical and pathological indicators was also assessed. Results Gastric tumour tissues expressed significantly higher levels of hCNT and hENT than normal stomach tissues (p=0.022 and p=0.0071, respectively for hCNT and hENT). Expression levels of the hCNT and hENT gene transcripts presented significant correlation with the overall survival (OS) (Hazard Ration (HR)=2.885, p&amp;lt;0.001 for hCNT; HR=2.078, p&amp;lt;0.001 for hENT) and disease-free survival of the patients (HR=2.434, p=0.004 for hCNT; HR=2.072, p&amp;lt;0.001). Patients with high levels of hCNT in their gastric tumours were more resisted to neoadjuvant therapies (HR=3.437, p=0.013, by ROC model), although the same was not seen with hENT. Conclusion hCNT and hENT have significant prognostic factors for patients with gastric cancer and theranostic factor for response to neoadjuvant therapies.