Gastric Stem Cells Research Articles

Stem Cell Biomarkers and Tumorigenesis in Gastric Cancer.

Stomach cancer has a high mortality, which is partially caused by an absence of suitable biomarkers to allow detection of the initiation stages of cancer progression. Thus, identification of critical biomarkers associated with gastric cancer (GC) is required to advance its clinical diagnoses and treatment. Recent studies using tracing models for lineage analysis of GC stem cells indicate that the cell fate decision of the gastric stem cells might be an important issue for stem cell plasticity. They include leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5+), Cholecystokinin receptor 2 (Cckr2+), and axis inhibition protein 2 (Axin2+) as the stem cell markers in the antrum, Trefoil Factor 2 (TFF2+), Mist1+ stem cells, and Troy+ chief cells in the corpus. By contrast, Estrogen receptor 1 (eR1), Leucine-rich repeats and immunoglobulin-like domains 1 (Lrig1), SRY (sex determining region Y)-box 2 (Sox2), and B lymphoma Mo-MLV insertion region 1 homolog (Bmi1) are rich in both the antrum and corpus regions. These markers might help to identify the cell-lineage identity and analyze the plasticity of each stem cell population. Thus, identification of marker genes for the development of GC and its environment is critical for the clinical application of cancer stem cells in the prevention of stomach cancers.

Distinct Wnt Signaling Thresholds Required for Polyposis in the Proximal and Distal Stomach

ObjectiveThe Wnt pathway is critical for gastrointestinal stem cell proliferation. Patients with Familial Adenomatous Polyposis (FAP) have germline mutations in the adenomatous polyposis coli (APC)gene, resulting in dysregulated Wnt signaling and a polyposis syndrome with stark regional differences in disease severity. In the stomach, the proximal corpus contains numerous polyps, while few polyps are located in the distal antrum. Here, we tested the hypothesis that there are regional differences in sensitivity to Wnt signaling along the gastric proximal‐distal axis, and that a ‘just‐right’ level of Wnt signaling is required for gastric polyposis.MethodsTo model gastric polyp formation in FAP patients, we used mice with an inducible Apcloss‐of‐function mutation. Gastric tissue responses were studied one month after maximal Wnt activation in homozygous Sox2‐CreERT2; Apc580flox/flox(APC‐/‐) and submaximal Wnt activation in heterozygous Sox2‐CreERT2; Apc580flox/+ (APC+/‐) mice. To gain insight into regional differences in Wnt response, RNA sequencing was performed on corpus and antral organoids treated with the Wnt inhibitor XAV939.ResultsIn the distal stomach, we observed hyperproliferation and tissue expansion in homozygous APC‐/‐ mice with no change in heterozygous APC+/‐mice. In contrast, the proximal stomach did not show an effect in homozygous APC‐/‐ mice but showed a modest increase in proliferation in heterozygous mice. PCR analysis of APC‐/‐ tissue confirmed APC gene deletion in the antrum, but not corpus, suggesting regional differences in maintenance of homozygous mutant stem cells. Following acute Wnt inhibition, corpus and antral organoids shared many Wnt‐regulated genes. However, Gene Ontology Enrichment analysis showed genes associated with cell differentiation, cell population proliferation, and cell cycle regulation were upregulated in antral organoids but downregulated in corpus organoids. KEGG analysis indicated downregulation of gastric cancer genes in both tissue organoids; however, only antral organoids showed downregulation of signaling pathways regulating pluripotency.ConclusionThe corpus and antrum exhibit differences in the Wnt signaling threshold required to initiate polyposis. Whereas submaximal levels of Wnt signaling are sufficient to initiate growth in the corpus, maximal levels are needed for antral hyperproliferation. Notably, ‘high‐Wnt’ stem cells are retained in the antrum and lost from the corpus, suggesting regional differences in Wnt regulation of gastric stem cells. Our findings in mouse highlight how heterozygous APC mutations may be sufficient for proximal stomach polyposis—a clinically relevant observation, as the vast majority of FAP patient gastric polyps are benign sessile growths located in the proximal stomach, with less frequent antral adenomatous polyps more closely associated with gastric cancer.

The Target of Chemoprevention for Gastric Cancer

Gastric Cancer (GC) is the fifth leading cancer in the world and the third leading cause of cancer-related death. The 5-year survival rate of advanced gastric cancer is less than 30%, it is very important to prevent gastric cancer. Current methods to prevent gastric cancer are eradication of H. pylori, early endoscopic diagnosis and early treatment. Chemoprevention of cancer is using of natural, synthetic, or biological substances to prevent, or reverse the development of cancer, thereby reducing the incidence and mortality of cancer. We will discuss the target of chemoprevention for gastric cancer based on the clue of regeneration of gastric mucosal epithelium from the perspectives of gastric stem cell proliferation and differentiation.

Inhibition of CCCTC Binding Factor-Programmed Cell Death Ligand 1 Axis Suppresses Emergence of Chemoresistance Induced by Gastric Cancer-Derived Mesenchymal Stem Cells.

BackgroundGastric cancer (GC) is the third leading cause of cancer-associated deaths worldwide. Stromal cells, especially mesenchymal stem cells (MSCs), play significant roles in the development of therapy resistance depending on their paracrine function. The PD-1/PD-L1 crosstalk between cancer and immune cells has been well studied. Emerging evidence suggests that PD-L1 also contributes to tumor resistance to therapy.MethodsCell survival and apoptosis were assessed using CCK-8, colony formation, and flow cytometry assays. Protein alterations were analyzed via Western blot. Gene knockdown and overexpression were achieved with siRNA/shRNA and lentiviral infection, respectively. Drug effects on tumors in vivo were assessed with xenografts in nude mice. In addition, GC patient samples after chemotherapy treatment were collected to observe the relationship between chemotherapy effect and CTCF or PD-L1.ResultsIn response to 5-fluorouracil or paclitaxel treatment, GCMSC-CM enhanced the cell viability and decreased the apoptosis rate. Furthermore, blocking PD-L1 or CTCF in GC cells prevented GCMSC-induced drug resistance accompanied by a decline in cell stemness. Consistent with these in vitro observations, mice treated with GCMSC-CM showed a lower sensitivity to 5-fluorouracil. In addition, high expression of CTCF and PD-L1 was associated with poor chemotherapy progression in the clinic.ConclusionStudy results demonstrate a mechanism where GCMSC-CM promotes GC chemoresistance by upregulating CTCF-PD-L1 and provide strong evidence in support of targeting CTCF-PD-L1 signaling as a strategy to prevent resistance in the clinic.

SLC26A9 deficiency causes gastric intraepithelial neoplasia in mice and aggressive gastric cancer in humans

BackgroundSolute carrier family 26 member (SLC26A9) is a Cl− uniporter with very high expression levels in the gastric mucosa. Here, we describe morphological and molecular alterations in gastric mucosa of slc26a9−/− mice and in selective parietal cell-deleted slc26a9fl/fl/Atp4b-Cre mice and correlate SLC26A9 expression levels with morphological and clinical parameters in a cohort of gastric cancer (GC) patients.MethodsThe expression patterns of genes related to transport and enzymatic function, proliferation, apoptosis, inflammation, barrier integrity, metaplasia and neoplasia development were studied by immunohistochemistry (IHC), quantitative RT-PCR, in situ hybridization and RNA microarray analysis. SLC26A9 expression and cellular/clinical phenotypes were studied in primary human GC tissues and GC cell lines.ResultsWe found that both complete and parietal cell-selective Slc26a9 deletion in mice caused spontaneous development of gastric premalignant and malignant lesions. Dysregulated differentiation of gastric stem cells in an inflammatory environment, activated Wnt signaling, cellular hyperproliferation, apoptosis inhibition and metaplasia were observed. Analysis of human gastric precancerous and cancerous tissues revealed that SLC26A9 expression progressively decreased from atrophic gastritis to GC, and that downregulation of SLC26A9 was correlated with patient survival. Exogenous expression of SLC26A9 in GC cells induced upregulation of the Cl−/HCO3− exchanger AE2, G2/M cell cycle arrest and apoptosis and suppressed their proliferation, migration and invasion.ConclusionsOur data indicate that SLC26A9 deletion in parietal cells is sufficient to trigger gastric metaplasia and the development of neoplastic lesions. In addition, we found that SLC26A9 expression decreases during human gastric carcinogenesis, and that exogenous SLC26A9 expression in GC cells reduces their malignant behavior.Graphical abstract

BMP feed-forward loop promotes terminal differentiation in gastric glands and is interrupted by H. pylori-driven inflammation

Helicobacter pylori causes gastric inflammation, gland hyperplasia and is linked to gastric cancer. Here, we studied the interplay between gastric epithelial stem cells and their stromal niche under homeostasis and upon H. pylori infection. We find that gastric epithelial stem cell differentiation is orchestrated by subsets of stromal cells that either produce BMP inhibitors in the gland base, or BMP ligands at the surface. Exposure to BMP ligands promotes a feed-forward loop by inducing Bmp2 expression in the epithelial cells themselves, enforcing rapid lineage commitment to terminally differentiated mucous pit cells. H. pylori leads to a loss of stromal and epithelial Bmp2 expression and increases expression of BMP inhibitors, promoting self-renewal of stem cells and accumulation of gland base cells, which we mechanistically link to IFN-γ signaling. Mice that lack IFN-γ signaling show no alterations of BMP gradient upon infection, while exposure to IFN-γ resembles H. pylori-driven mucosal responses.

Homeostasis and Cancer Initiation: Organoids as Models to Study the Initiation of Gastric Cancer.

Gastric cancer represents a significant disease burden worldwide. The factors that initiate cancer are not well understood. Chronic inflammation such as that triggered by H. pylori infection is the most significant cause of gastric cancer. In recent years, organoid cultures developed from human and animal adult stem cells have facilitated great advances in our understanding of gastric homeostasis. Organoid models are now being exploited to investigate the role of host genetics and bacterial factors on proliferation and DNA damage in gastric stem cells. The impact of a chronic inflammatory state on gastric stem cells and the stroma has been less well addressed. This review discusses what we have learned from the use of organoid models to investigate cancer initiation, and highlights questions on the contribution of the microbiota, chronic inflammatory milieu, and stromal cells that can now be addressed by more complex coculture models.

Inhibition of Musashi-1 enhances chemotherapeutic sensitivity in gastric cancer patient-derived xenografts.

Musashi-1 (MSI1), a neural RNA-binding protein, is considered a gastric and intestinal stem cell marker. Although the function of MSI1 in gastric cancer has attracted increasing interest, it is not known whether MSI1 can be used as a biomarker to monitor gastric cancer development and response to treatment. Here, the role of MSI1 in the chemotherapeutic sensitivity of gastric cancer was investigated. Patients with high MSI1 levels had poor outcomes, implicating the gene in the development and progression of the disease. We overexpressed and silenced MSI1 in the human gastric cancer cell lines MKN45 and HGC27, finding that knockdown reduced proliferation, invasion, and migration, while promoting apoptosis. A patient-derived xenograft gastric cancer model was constructed in which mice received chemical drugs, si-MSI1, or a drug-si-MSI1 combination. It was found that blocking MSI1 expression reduced gastric cancer drug tolerance. The combination treatment with si-MSI1 was superior to 5F-dUMP and cisplatin, either separately or in combination, indicating that including si-MSI1 was better than drug therapy alone. Transcriptome sequencing analysis showed that MSI1 altered cell cycle regulation and growth signal transduction, including that of blood vessel epicardial substance (BVES). These results suggest that MSI1 reduces the tolerance of gastric cancer to chemical drugs through modulation of MSI1/BVES signaling.

Gastric Organoids: Progress and Remaining Challenges.

The stomach is a complex and physiologically necessary organ, yet large differences in physiology between mouse and human stomachs have impeded translation of physiological discoveries and drug screens performed using murine gastric tissues. Gastric cancer (GC) is a global health threat, with a high mortality rate and limited treatment options. The heterogeneous nature of GC makes it poorly suited for current “one size fits all” standard treatments. In this review, we discuss the rapidly evolving field of gastric organoids, with a focus on studies expanding cultures from primary human tissues and describing the benefits of mouse organoid models. We introduce the differing methods for culturing healthy gastric tissue from adult tissues or pluripotent stem cells, discuss the promise these systems have for preclinical drug screens, and highlight applications of organoids for precision medicine. Finally, we discuss the limitations of these models and look to the future to present potential ways gastric organoids will advance treatment options for patients with GC.

Delta-like 1-Expressing Cells at the Gland Base Promote Proliferation of Gastric Antral Stem Cells in Mouse.

Background & AimsNotch pathway signaling maintains gastric epithelial cell homeostasis by regulating stem cell proliferation and differentiation. We previously identified NOTCH1 and NOTCH2 as the key Notch receptors controlling gastric stem cell function. Here, we identify the niche cells and critical Notch ligand responsible for regulating stem cell proliferation in the distal mouse stomach.MethodsExpression of Notch ligands in the gastric antrum was determined by quantitative reverse-transcriptase polymerase chain reaction and cellular localization was determined by in situ hybridization and immunostaining. The contribution of specific Notch ligands to regulate epithelial cell proliferation in adult mice was determined by inducible gene deletion, or by pharmacologic inhibition using antibodies directed against specific Notch ligands. Mouse gastric organoid cultures were used to confirm that Notch ligand signaling was epithelial specific.ResultsDelta-like 1 (DLL1) and Jagged 1 (JAG1) were the most abundantly expressed Notch ligands in the adult mouse stomach, with DLL1 restricted to the antral gland base and JAG1 localized to the upper gland region. Inhibition of DLL1 alone or in combination with other Notch ligands significantly reduced epithelial cell proliferation and the growth of gastric antral organoids, while inhibition of the other Notch ligands, DLL4, JAG1, and JAG2, did not affect proliferation or organoid growth. Similarly, DLL1, and not DLL4, regulated proliferation of LGR5+ antral stem cells, which express the NOTCH1 receptor.ConclusionsDLL1 is the key Notch ligand regulating epithelial cell proliferation in the gastric antrum. We propose that DLL1-expressing cells at the gland base are Notch niche cells that signal to adjacent LGR5+ antral stem cells to regulate stem cell proliferation and epithelial homeostasis.

Gastric Cancer Mesenchymal Stem Cells Inhibit NK Cell Function through mTOR Signalling to Promote Tumour Growth.

The dysfunction of natural killer (NK) cells has been increasingly reported in malignancies, especially in solid tumours. Mesenchymal stem cells (MSCs) exhibit pleiotropic functions that include mediating immune cell exhaustion which is implicated in cancer progression. However, the association of MSCs derived from gastric cancer (gastric cancer mesenchymal stem cells: GCMSCs) with the dysfunction of NK cells remains poorly understood. In this study, we demonstrated that GCMSCs effectively contributed to the exhaustion of NK cells through the release of soluble factors. Furthermore, passivation of the antitumour effect in NK cells was closely associated with their dysfunctional state. The GCMSC-conditioned medium prevented the frequency and effector function of infiltrating NK cells in tumour-bearing mouse models, thus promoting tumour growth. Mechanistically, mammalian target of rapamycin (mTOR) signalling, a critical regulator of cellular metabolism that mediates the function of immune cells, was inhibited in NK cells treated with GCMSCs. However, the checkpoint receptor PD-1 was still present at minimal levels with or without GCMSCs. The study results revealed that GCMSCs contributed to dysfunctional NK cells involved at least partially in the inhibition of mTOR signalling, suggesting potential directions for NK cell-based cancer immunotherapy.

Modulation of Stem Cell Progeny by Probiotics during Regeneration of Gastric Mucosal Erosions.

Simple SummaryThe wall of the stomach is easily damaged by different factors leading to serious diseases such as ulcers and cancer. In this study, the effects of a mixture of different types of beneficial bacteria (De Simone Formulation) were investigated in a mouse model of stomach wall damages induced by single or multiple doses of acetylsalicylic acid. Control mice received water. The stomachs of all mice were processed for microscopic examination and labeling of dividing stem cells and stomach cell lineages secreting mucus, acid, pepsin, and hormones. The results reveal beneficial effects for the multiple bacterial strain of De Simone Formulation given before or after the induction of stomach erosions. The regeneration of the stomach wall was associated with an increase in stem cell proliferation and enhanced production of protective factors such as mucus, and restoration of the aggressive factors produced by acid and pepsin secreting cell lineages. Therefore, the protective and therapeutic effects of the multi-strain healthy bacteria against stomach erosions involve modulation of not only dividing stem cells but also the multiple secretory cell lineages of the stomach.Patients with gastric mucosal erosions are predisposed to chronic gastritis, ulcer or even cancer. The repair of mucosal erosions involves several events including proliferation of gastric epithelial stem cells. The aim of this study was to investigate the effects of the probiotic mixture of De Simone Formulation on gastric epithelial stem cell lineages in mouse models of gastric mucosal erosions. Gastric erosions were induced by a single oral gavage of 80% ethanol containing 15 mg/mL acetylsalicylic acid (5 mL/kg) following a daily dose of probiotic mixture (5 mg/day/mouse) for 10 days. In another protocol, erosions were induced by a daily gavage of acetylsalicylic acid (400 mg/kg/day/mouse) for 5 days before or after daily administration of probiotic mixture for 5 days. Control mice received water gavage for 10 days. All mice were injected with bromodeoxyuridine two hours before sacrifice to label S-phase cells. The stomachs of all mice were processed for histological examination, lectin binding, and immunohistochemical analysis. The results reveal that mice that received probiotics before or after the induction of erosion showed a decrease in erosion index with an increase in gastric epithelial stem/progenitor cell proliferation and enhanced production of mucus, trefoil factors, and ghrelin by mucous and enteroendocrine cell lineages. These mice also showed restoration of the amount of H+,K+-ATPase and pepsinogen involved in the production of the harsh acidic environment by parietal and chief cell lineages. In conclusion, this study demonstrates the beneficial effects of probiotics against gastric mucosal erosion and highlights the involvement and modulation of proliferative stem cells and their multiple glandular epithelial cell lineages.

Gastric Stem Cells Are Targeted in Upper Gastrointestinal GVHD

Introduction: Graft-versus-host disease (GVHD) is the major obstacle to perform allogeneic hematopoietic stem cell transplantation (SCT). We previously demonstrated that intestinal stem cells (ISCs) were targeted in lower gastrointestinal (GI) GVHD (Takashima et al, J Exp Med. 2011). However, it remains to be investigated whether gastric stem cells (GSCs) could be targeted in upper GI GVHD. We evaluated if leucine-rich repeat-containing G protein-coupled receptor (Lgr) 5+ GSCs, which replenish antrum and pyloric epithelium, could be damaged in GVHD. Wnt agonist R-Spondin 1 (R-Spo1), which binds to Lgr5, protects ISCs and ameliorates GVHD. We also evaluated if R-Spo1 could protect Lgr5+GSCs against GVHD.Methods: B6D2F1 mice (H-2b/d) were transplanted with 5 × 106 splenocytes plus 5 × 106 bone marrow cells from allogeneic B6 (H-2b) or syngeneic B6D2F1 donors following lethal X-ray total body irradiation on day 0 and histological evaluation of the pylorus and antrum of stomach and flow cytometric analysis of infiltrating donor T cells in the stomach were performed on day +7 after SCT. Recipients of SCT were intravenously injected with 100 μg/day of R-Spo1 from days -3 to -1 and days +1 to +3 after SCT, or naïve mice were injected with 200 µg/day of R-Spo1 for six days.Results: We investigated the fate of GSCs after SCT in Lgr5-creERT2 / eGFP B6D2F1 recipients. Immunofluorescent studies demonstrated development of gastric GVHD with significant donor T-cell infiltration in the lamina propria of gastric mucosa and cleaved-caspase-3+ apoptotic epithelial cells in the stomach of allogeneic animals, but not in syngeneic controls (Figure A). Numbers of Lgr5+ GSCs were significantly decreased in allogeneic recipients compared to those in syngeneic controls on day +7, suggesting that gastric GVHD targets Lgr5+ GSCs (Figure B). We then evaluated effects of R-Spo1 on GSCs. When injected to naïve B6D2F1 mice for 6 days, R-Spo1 significantly prolonged the crypt depth with an increase in numbers of Ki-67+ proliferating epithelial cells in the stomach. Fate mapping analysis using Lgr5-creERT2/eGFP × Rosa26Tomato mice, in which Lgr5+ GSCs and their progenies are labeled with tdTomato and Lgr5+ GSCs are labeled with eGFP, showed that R-Spo1 did not increase eGFP+ GSCs but significantly increased Ki67+ cells and tdTomato+ epithelial cells. These data suggested that R-Spo1 stimulated differentiation of Lgr5+ GSCs into mucosal epithelial cells. We then tested if GVHD prophylaxis with R-Spo1 protects GSCs and ameliorates gastric GVHD after allogeneic SCT. Immunofluorescent analysis showed that brief administration of R-Spo1 significantly suppressed infiltration of donor T-cells and epithelial apoptosis, and protected GSCs from GVHD 7 days after allogeneic SCT (Figure A, B).Conclusion: Lgr5+ GSCs are targeted in upper GI GVHD and R-Spo1 protects GSCs against GVHD after allogeneic SCT.Figure: After allogeneic SCT, cleaved-caspase-3+ apoptotic epithelium was significantly increased (A), and number of Lgr5+ GSCs was significantly decreased on day +7 (B). R-Spo1 inhibited epithelial apoptosis (A) and Lgr5+ GSC loss (B). [Display omitted] DisclosuresTeshima:Astellas: Research Funding; Kyowa-Hakko Kirin: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfeizer: Research Funding; Chugai: Research Funding; Bristol-Myers Squibb: Research Funding.

3,3'-Diindolylmethane Promotes Gastric Cancer Progression via β-TrCP-Mediated NF-κB Activation in Gastric Cancer-Derived MSCs.

Gastric cancer is a malignant tumor characterized by high morbidity and invasion. Surgery combined with chemo-radiotherapy is the most common treatment for gastric cancer, while multiple drug resistance always results in treatment failure. Once the anti-tumor drugs enter the tumor foci, tumor cells as well as those found in the microenvironment are affected. However, the effects of drugs on tumor microenvironment (TME) are easily overlooked. In this study, we investigated the effects of the anti-cancer drug 3,3’-diindolylmethane (DIM) on gastric cancer-derived mesenchymal stem cells (GC-MSCs) and their subsequent impact on cancer progression. Surprisingly, we found that the therapeutic concentration of DIM upregulated the expression level of tumor-related factors such as CCL-2, IL-6, and IL-8 in GC-MSCs. The conditioned medium of DIM-treated GC-MSCs promoted the proliferation, invasion, and migration of gastric cancer cells in vitro and tumor growth in vivo. Mechanistically, DIM enhanced the expression of β-TrCP, an E3 ubiquitin ligase leading to IκBα degradation and NF-κB activation in GC-MSCs. The β-TrCP knockdown partially eliminated positive results caused by DIM. Our results showed that the therapeutic dosage of DIM induced cell death in cancer cells, while enhancing MSC paracrine functions in the stroma to offset the original DIM effect on cancer cells. These findings provide a new mechanism of anti-cancer drug resistance and remind us to adjust the chemotherapeutic scheme by combining the anti-cancer drug with an appropriate signaling pathway inhibitor to block the side effects of drug on targeted TME cells.

G6PD-NF-κB-HGF Signal in Gastric Cancer-Associated Mesenchymal Stem Cells Promotes the Proliferation and Metastasis of Gastric Cancer Cells by Upregulating the Expression of HK2.

Background: Tumor-associated stromal cells have been widely recognized for their tumor-promoting capability involving paracrine signaling. However, the underlying mechanism and the effects of the molecules in the glycolysis pathway in gastric cancer-associated mesenchymal stem cells (GCMSCs) and gastric cancer cells on tumor progression remain unclear.Methods: The expression of hepatocyte growth factor (HGF) in GCMSCs and bone marrow mesenchymal stem cells (BMMSCs) was detected by enzyme-linked immunosorbent assay (ELISA). The effect of HGF derived from GCMSCs on the proliferation, metastasis, and HK2 expression of gastric cancer cells was evaluated in vitro and in vivo. The effects of G6PD on the production of HGF in mesenchymal stem cells (MSCs) were analyzed by immunoblotting.Results: HGF derived from GCMSCs promoted glycolysis, proliferation, and metastasis of gastric cancer by upregulating c-Myc-HK2 signal. The progression of the disease induced by GCMSCs decelerated in the absence of HK2. The expression of G6PD activated NF-κB signaling and stimulated the production of HGF in GCMSCs. Blocking HGF derived from GCMSCs decreased proliferation, metastasis, and angiogenesis of gastric cancer cells in vivo.Conclusions: GCMSCs highly expressed G6PD and facilitated the progression of gastric cancer through the G6PD-NF-κB-HGF axis coordinates. Blocking HGF derived from GCMSCs is a potential new therapeutic target for the treatment of gastric cancer.

Most colitis associated carcinomas lack expression of LGR5: a preliminary study with implications for unique pathways of carcinogenesis compared to sporadic colorectal carcinoma

BackgroundLeucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5), a component of the Wnt receptor complex, is thought to lineage label gastric and intestinal stem cells. LGR5 expression is increased in colorectal carcinoma (CRC) compared to normal tissue. Colitis associated colorectal adenocarcinoma (CAC) often shows distinct morphologic and molecular phenotypes compared to sporadic cases. However, the expression profile of LGR5, and by extension the potential role of an intestinal stem cell phenotype, has not been well described in a series of human CAC.MethodRNA in situ hybridization (ISH) for LGR5 expression on 30 CACs (12 cases with conventional morphology and 18 cases with non-conventional type morphology) from 29 inflammatory bowel disease (IBD) patients was performed and compared the expression profile to a control group of 10 sporadic CRCs. Immunohistochemistry for beta-catenin and SATB2 was performed on the 30 CACs.ResultLGR5 was positive in 30% (9/30) of CAC cases and 90% (9/10) of sporadic CRCs (p = 0.002). A large majority (89%) of LGR5 positive CACs were of the conventional histologic type, and conventional type CAC showed a significantly higher LGR5 score (median 3.0; interquartile range 1.75–3.25) than non-conventional type CAC (median 1.5; interquartile range 1.00–2.00) (p = 0.034). CAC with conventional morphology did have a lower level of LGR5 expression than sporadic CRC. Sporadic CRCs showed a significantly higher LGR5 level score than non-conventional type CACs (p < 0.001). Nuclear translocation of beta-catenin was strongly associated with LGR5 expression (p = 0.003), however no significant association was identified between SATB2 expression and LGR5 expression status in CACs.ConclusionThese findings suggest that the wider spectrum of tumor morphology in CAC may be associated with absence of a LGR5-expressing intestinal stem cell phenotype.

Gastric cancer mesenchymal stem cells inhibit natural killer cell function by up-regulating FBP1.

IntroductionThe dysfunction of natural killer (NK) cells has been widely reported in malignancies, including in solid tumours. Gastric cancer mesenchymal stem cells (GCMSCs) are one of the vital elements of stromal cells in the tumour environment (TME) which possess immunosuppressive activity. This study aimed to determine whether GCMSCs are involved in the inhibition of NK cell immune function and explore its underlying mechanism.Material and methodsCD107a and perforin expression of GCMSCs conditioned medium (GCMSCs-CM)-primed NK cells were detected by flow cytometry. To determine NK cell cytotoxicity, the CytoTox96 Non-Radioactive Cytotoxicity Assay kit was used. Glucose uptake and lactate production assay were performed to evaluate the metabolism state of NK cells treated with GCMSCs-CM. The expression of FBP1 in NK cells was analysed by immunoblotting.ResultsGCMSCs inhibited the degranulation capacity, perforin production and cytotoxicity of NK cells. GCMSCs-CM restrained NK cell glucose uptake and lactate production, thus weakening their glycolytic metabolism. FBP1 expression of NK cells was upregulated in the presence of GCMSCs-CM. Using FBP1 inhibitor could reverse the dysfunctional state of NK cells.ConclusionsThis study indicated that GCMSCs could exert immunosuppressive effects on NK cells by up-regulating FBP1 expression, opening up new avenues for NK cell-based GC immunotherapy.

Experimental Study on the Combined Killing Effect of DC and CIK Cells on Gastric Cancer Stem Cells

Background: Gastric cancer is one of the most fatal malignant tumors in China. Gastric cancer stem cells are the key factors of tumor recurrence and metastasis. In recent years, immunotherapy for gastric cancer stem cells has become a research hotspot. Objective: to preliminarily verify the combined killing effect of DC and CIK cells on gastric cancer stem cells. To evaluate the effect of DC-CIK cells as a potential therapeutic agents for gastric cancer. Methods: Based on human gastric cancer cell line SGC7901, gastric cancer stem cells were isolated and cultured by immunomagnetic beads. The cytotoxicity of DC-CIK effector cells to gastric cancer stem cells was investigated by ⁵¹Cr killing test. The cell cycle and apoptosis of tumor stem cells were detected by flow cytometry. Then the comparisions of the cytotoxicity activity between DC-CIK and CIK only was conducted. Results: the gastric cancer stem cells isolated and cultured by CD44 and CD133 immunomagnetic beads sorting method met the research requirements. ⁵¹Cr cell killing test results showed that the killing rate of DC-CIK combined as effector cells on gastric cancer SGC7901 stem cell line was significantly higher than those of the control group (P<0.05). After DC-CIK effector cells treatment, the apoptosis rate of tumor stem cells increased significantly. Conclusion: preliminary in vitro experiments show that DC-CIK cells combined as effector cells have obvious killing effect on gastric cancer stem cells, which could has potential clinical application value for controlling recurrence and metastasis of gastric cancer after surgery, radiotherapy and chemotherapy.

Ki-67 Immunohistochemical Evaluation of Changes in Gastric Stem Cell Population with Age

Digestive diseases resulting from atrophy and metaplasia become more common as people get older, resulting in anatomical and functional abnormalities in the gastrointestinal system. The integrity and health of all parts of the digestive system depend largely on the presence of an adequate stem cell population. The study aimed to analyze the gastric stem cell population of different ages, using Ki-67 immunohistochemistry. Twenty-one adult male albino rats were distributed into 3 age groups, each

Wnt Signaling Shapes the Histologic Variation in Diffuse Gastric Cancer

Diffuse-type gastric cancer (GC) is currently subdivided into signet-ring cell carcinoma (SRCC) and non-SRCC, referred to as poorly cohesive carcinoma not otherwise specified (PCC-NOS). Although these subtypes are considered to be independent, they often coexist in the same tumors, raising a question of whether they clonally differ or not. To tackle this question, we established an experimental platform for human diffuse GC that enables accurate modeling of histologic subtypes. Seven patient-derived diffuse GC organoid lines were established, characterized by histopathologic analysis, in situ hybridization, and gene expression analysis. For genetic modeling of diffuse GC, we knocked out CDH1 and/or TP53 in human normal gastric organoids. Green fluorescent protein-labeled GC organoids were xenotransplanted into immune-deficient mice for invivo assessment. PCC-NOS organoids transformed into SRCC-like structures on removal of Wnt and R-spondin from the culture medium. This morphologic change paralleled downregulation of Wnt-target and gastric stem cell genes, including LGR5, and elevation of differentiation markers, such as KRT20 and MUCs. The association between Wnt target gene expression and histologic subtypes was confirmed in 3 patient-derived GC tissues. Invivo, single clone-derived organoids formed tumors that comprised 2 distinct histologic compartments, each corresponding to SRCC and PCC-NOS. The transition from PCC-NOS to SRCC histology reflected the abundance of surrounding R-spondin-expressing fibroblasts. SRCC and PCC-NOS were clonally identical, and their morphology was regulated by extracellular Wnt and R-spondin expression. Our results decoded how genetic mutations and the tumor environment shape pathohistologic and biologic phenotypes in human diffuse GCs.