Gastric Mucosal Epithelial Cells Research Articles

IL-1R2 expression in human gastric cancer and its clinical significance.

Background: Interleukin-1 receptor type II (IL-1R2), also known as CD121b, is a member of the IL-1 receptor family. IL-1R2 acts as negative regulator of the IL-1 system, modulating IL-1 availability for the signaling receptor. IL-1R2 is abnormally expressed in many human inflammatory diseases and cancers, and has important clinical significance. The present study was designed to investigate IL-1R2 expression in human gastric cancer (GC) tissues and the associated clinical implications. Methods: Immunohistochemistry was used to identify the clinical significance and prognostic value of IL-1R2 expression in GC tissues. We investigated IL-1R2 expression in GC tissues, cells, and serum using real-time PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) assays. Results: IL-1R2 was highly expressed in GC tissues, and the overall survival in patients with advanced GC and high IL-1R2 expression was significantly poorer than that in patients with advanced GC and low IL-1R2 expression. Moreover, IL-1R2 mRNA levels in GC tissues and most GC cells were higher than those in para-cancer tissues and GES1 human gastric mucosal epithelial cells. The level of plasma-soluble IL-1R2 in GC patients was higher than that of the healthy control group. Conclusion: Increased IL-1R2 levels are involved in the initiation and progression of human GC, and IL-1R2 might be employed to develop immunotherapeutic approaches targeting GC.

Assessing the Regulatory Functions of LncRNA SNHG11 in Gastric Cancer Cell Proliferation and Migration.

The aim of this study was to assess the regulatory functions of SNHG11 in gastric cancer (GC) cell proliferation and migration. Dual-luciferase reporter assay and bioinformatics prediction [starBase (http://starbase.sysu.edu.cn/) and TargetScan (http://www.targetscan.org)] indicated that SNHG11 functions as a miR-184 sponge that can directly act on CDC25A. Compared with normal healthy gastric tissue and mucosal epithelial cell GES-1, SNHG11 and CDC25A expressions were dramatically increased in GC samples and cell lines, whereas microRNA-184 (miR-184) levels were reduced. SNHG11 silencing led to increased miR-184 and reduced CDC25A, whereas miR-184 downregulation recovered the expression of CDC25A. Additionally, miR-184 upregulation also played a role in regulating CDC25A ablation. Then, SNHG11 was silenced or miR-184 was upregulated in two GC cells (SGC-7901 and MKN-28). SNHG11 silencing and miR-184 upregulation caused a notable decrease in GC cell growth and proliferation and increased the apoptotic level of GC cells. Furthermore, SNHG11 silencing and miR-184 upregulation contributed to a decreased migration capacity of GC cells. Downregulated miR-184 expression in SNHG11 silenced GC cells showed that miR-184 inhibition reversed the effect of SNHG11 silencing on the growth, proliferation, apoptosis, and migration of GC cells. Moreover, in vivo xenograft experiments demonstrated that SNHG11 knockdown can inhibit tumor growth. These observations confirmed that SNHG11 acts as an oncogene, whereas miR-194 served as a tumor suppressor in GC development. SNHG11 may provide a new biomarker for GC diagnosis, treatment, and prognosis.

Up-regulation of DGAT1 in cancer tissues and tumor-infiltrating macrophages influenced survival of patients with gastric cancer

BackgroundDiacylglycerol-acyltransferase 1 (DGAT1) plays an important role in the energy storage and is involved in cancer progression. A growing number of evidences showed that elevated expression of DGAT1 in cancer tissue indicated a poor outcome in cancer patients. However, the relationship between DGAT1 and gastric cancer is still unclear. Thus, Transcriptomic analysis and in vitro experiments were performed to investigate the role of DGAT1 in gastric cancer, as well as the potential therapy target in gastric cancer treatment.MethodsWe screened the public cancer datasets to identify the expression and function of DGAT1 in gastric cancer and tumor infiltrating lymphocytes. Then we testified the DGAT1 expression and function after sodium oleate treatment in AGS and MKN45 cell line. Finally, we analyzed ration of apoptosis, necrosis in gastric cancer cells by using flow cytometry after administration of DGAT1 inhibitor.ResultsOur results showed a highly expression of DGAT1 in gastric cancer tissues (n = 5, p = 0.0004), and tumor-infiltrating macrophages with elevated DGAT1 expression is associated with poor overall survival in gastric cancer patients. In addition, gastric cell lines AGS (n = 3, p < 0.05) and MKN45 (n = 3, p < 0.01) expressed higher level of DGAT1 than human gastric mucosal epithelial cell line GES-1. Administration of DGAT1 inhibitor effectively suppressed functional factors expression and induced cell death in MKN45.ConclusionThe findings of this research provide an in-depth insight into the potential role and influences involved in DGAT1 in the gastric cancer patients. And higher expression of DGAT1 leads to lower overall survival (OS) rate in patients with poorly differentiated gastric cancer. Our findings suggest a potential role for DGAT1 in the gastric cancer progression and inhibiting DGAT1 might be a promising strategy in gastric cancer treatment.

Knockdown of RIPK2 Inhibits Proliferation and Migration, and Induces Apoptosis via the NF-κB Signaling Pathway in Gastric Cancer.

RIPK2 is a 62 kDa protein and a member of the receptor interacting protein kinases (RIPK) family. It was previously demonstrated that RIPK2 might play a role in promoting malignant tumor progression; however, the precise function of RIPK2 in the onset and progression of gastric cancer (GC) remains unclear. In the current study, we investigated the role of RIPK2 in GC. First, we explored the expression levels of RIPK2 in multiple cancers, including GC, using a bioinformatics approach. We constructed the RIPK2-associated protein-protein interaction network using the search tool for the retrieval of interacting genes/proteins for gene ontology and Kyoto encyclopedia of genes and genomes analysis. Next, we compared the RIPK2 expression levels between GC cells and normal gastric mucosal epithelial cell (GES-1) using reverse transcription quantitative PCR analysis. We downregulated the expression of RIPK2 in GC cells to determine the effects of RIPK2 on cell growth, migration, and apoptosis. Finally, we used western blotting to investigate the RIPK2 downstream signaling pathway involved in the regulation of GC progression. Our results showed that RIPK2 was overexpressed in various tumor tissues, including GC, compared to non-cancer tissues. Moreover, RIPK2 expression was significantly upregulated in all four GC cell lines (MGC-803,SGC-7901, HGC-27 and AGS) comparing the GES-1 cells. Silencing of RIPK2 suppressed GC cell growth by inhibiting migration, and inducing apoptosis through the nuclear factor-κB (NF-κB) signaling pathway. In summary, we demonstrate that RIPK2 plays an important role in modulating GC cell proliferation, migration, and apoptosis through the NF-κB signaling pathway. Therefore, RIPK2 functions as a potential oncogene. We believe that RIPK2 can be used as a candidate biomarker, as well as a diagnostic tool, and the therapeutic target for GC.

Panax Notoginseng Saponin Attenuates Gastric Mucosal Epithelial Cell Injury Induced by Dual Antiplatelet Drugs through COX and PI3K/Akt/ VEGF-GSK-3β-RhoA Network Pathway.

To elucidate the underlying mechanism of Panax notoginseng saponin (PNS) on gastric epithelial cell injury and barrier dysfunction induced by dual antiplatelet (DA). Human gastric mucosal epithelial cell (GES-1) was cultured and divided into 4 groups: a control, a DA, a PNS+DA and a LY294002+PNS+DA group. GES-1 apoptosis was detected by flow cytometry, cell permeability were detected using Transwell, level of prostaglandins E2 (PGE2), 6-keto-prostaglandin F1α (6-keto-PGF1α) and vascular endothelial growth factor (VEGF) in supernatant were measured by enzyme linked immunosorbent assay (ELISA), expression of phosphatidylinositide 3-kinase (PI3K), phosphorylated-PI3K (p-PI3K), Akt, phosphorylated-Akt (p-Akt), cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), glycogen synthase kinase-3β (GSK-3β) and Ras homolog gene family member A (RhoA) were measured by Western-blot. DA induced apoptosis and hyper-permeability in GES-1, reduced supernatant level of PGE2, 6-keto-PGF1α and VEGF (P<0.05). Addition of PNS reduced the apoptosis of GES-1 caused by DA, restored the concentration of PGE2, 6-keto-PGF1α and VEGF (P<0.05). In addition, PNS attenuated the alteration of COX-1 and COX-2 expression induced by DA, up-regulated p-PI3K/p-Akt, down-regulated RhoA and GSK-3β. LY294002 mitigated the effects of PNS on cell apoptosis, cell permeability, VEGF concentration, and expression of RhoA and GSK-3β significantly. PNS attenuates the suppression on COX/PG pathway from DA, alleviates DA-induced GES-1 apoptosis and barrier dysfunction through PI3K/Akt/ VEGF-GSK-3β-RhoA network pathway.

Circ_0044516 functions in the progression of gastric cancer by modulating MicroRNA-149-5p/HuR axis.

Circular RNAs (circRNAs) have emerged as a multifunctional class of RNAs, while there is limited knowledge on their functions in the development of cancers. Herein, we performed the current study to probe into the regulatory mechanism of circ_0044516 in malignant behaviors of gastric cancer (GC) cells with the involvement of microRNA (miR)-149-5p/human antigen R (HuR) axis. Firstly, the expression levels of circ_0044516 in GC cell lines and normal gastric mucosal epithelial cells were determined by qRT-PCR, and GC cell lines with the highest expression of circ_0044516 were screened for further cell experiments. Subsequently, the biological functions of silenced circ_0044516 in GC were identified by CCK-8, colony formation, and transwell assays. Xenograft mouse models were established for in vivo verification. Furthermore, luciferase reporter, RIP, RNA pull-down assay and rescue experiments were performed to explore the sponge regulatory mechanism of circ_0044516. circ_0044516 was suggested to be highly expressed in GC cell lines, and circ_0044516 could promote GC cell proliferation, migration and invasion, as well as in vivo tumor growth. In addition, silenced circ-0044516 reversed the promotive roles in cell viability caused by overexpressed HuR. Furthermore, circ_0044516 mainly localized in the cytoplasm, which may act as a miR-149-5p sponge to modulate HuR expression, thereby playing an essential role in GC development. This study suggests that circ_0044516 may promote HuR expression through sponging miR-149-5p, thereby playing a part in GC progression.

Titanium implants modified by laser microtexturing enhance the bioactivity of gastric epithelial cells and fibroblast cells.

The clinical application of anastomotic instruments improves the efficiency of the digestive tract surgery. However, the stapler with titanium nails implanted is still controversial in terms of anastomotic complications, and further improvement and optimization are needed. The purpose of this study was to explore the optimal microtextured parameters that could enhance the bioactivity of titanium implants in vitro. Laser microtexturing technology was used to construct the groove-type microstructural surfaces with different parameters, and human gastric mucosal epithelial cells (GES-1 cells) and mouse fibroblasts (3T3 cells) were cultured on the surface of the titanium plates in vitro. The data of cell adhesion, cell proliferation and cell activity were obtained and statistically analyzed. The textured titanium plates meet the expected design. GES-1 and 3T3 cell adhesion were better in the surface of titanium plates in microstructural group than that in the polished group. GES-1 and 3T3 cells also showed higher proliferative activity in the microstructural group compared with the polished group. The laser textured titanium plates have good groove-type microstructure, which increase the surface roughness, change the surface wettability, promote the adhesion, proliferating and orderly growth of GES-1 and 3T3 cells, and show good biological properties.

Inhibition of Glutamine Uptake Improves the Efficacy of Cetuximab on Gastric Cancer.

Treatment for advanced gastric cancer is challenging. Epidermal growth factor receptor (EGFR) contributes to the proliferation and development of gastric cancer (GC), and its overexpression is associated with unfavorable prognosis in GC. Cetuximab, a monoclonal antibody targeting EGFR, failed to improve the overall survival of gastric cancer patients indicated in phase III randomized trials. Glutamine is a vital nutrient for tumor growth and its metabolism contributes to therapeutic resistance, making glutamine uptake an attractive target for cancer treatment. The aim of the present study was to investigate whether intervention of glutamine uptake could improve the effect of cetuximab on GC. The results of MTT assay showed that by glutamine deprivation or inhibition of glutamine uptake, the viability of gastric carcinoma cells was inhibited more severely than that of human immortal gastric mucosa epithelial cells (GES-1). The expression of the key glutamine transporter alanine-serine-cysteine (ASC) transporter 2 (ASCT2; SLC1A5) was significantly higher in gastric carcinoma tissues and various gastric carcinoma cell lines than in normal gastric tissues and cells, as shown by immunohistochemistry and western blotting, while silencing ASCT2 significantly inhibited the viability and proliferation of gastric carcinoma cells. Consistent with previous studies, it was shown herein by MTT and EdU assays that cetuximab had a weak inhibitory effect on the cell viability of gastric carcinoma cells. However, inhibiting glutamine uptake by blockade of ASCT2 with l-γ-glutamyl-p-nitroanilide (GPNA) significantly enhanced the inhibitory effect of cetuximab on suppressing the proliferation of gastric cancer both in vitro and in vivo. Moreover, combining cetuximab and GPNA induced cell apoptosis considerably in gastric carcinoma cells, as shown by flow cytometry, and had a higher depressing effect on gastric cancer proliferation both in vitro and in vivo, as compared to either treatment alone. The present study suggested that inhibition of glutamine uptake may be a promising strategy for improving the inhibitory efficacy of cetuximab on advanced gastric cancer.

Knockdown of lncRNA SNHG4 suppresses gastric cancer cell proliferation and metastasis by targeting miR-204-5p.

Long non-coding RNAs (lncRNAs) have been identified as critical regulators in gastric cancer (GC) progression. However, whether lncRNA small nucleolar host gene 4 (SNHG4) functions in GC development remains unknown. In this study, the bio-functional role of SNHG4 and its potential mechanism on GC progression were systematically dissected. To investigate the role of SNHG4 in GC, we silenced SNHG4 using short hairpin RNAs (shRNAs) to perform loss-of-function assays. The results showed that SNHG4 expression in GC cells was at a higher level compared to normal gastric mucosal epithelial cells. Knockdown of SNHG4 dramatically suppressed proliferation, migration and invasion, and blocked cell cycle progression of GC cells. Moreover, knockdown of SNHG4 upregulated microRNA-204-5p (miR-204-5p) expression, whereas downregulated ribonucleotide reductase subunit M2 (RRM2) expression in GC cells. Dual-luciferase reporter assay results showed that miR-204-5p was a direct target of SNHG4. Additionally, knockdown of SNHG4 suppressed GC tumorigenesis in xenograft mouse models. Taken together, these data demonstrated that knockdown of SNHG4 suppressed GC development by targeting miR-204-5p.

Effects of miR-362 in Regulating the Proliferation, Invasion and Apoptosis of Gastric Cancer by Inhibiting the Expression of Tumor-Promoting Factor PRDM2

Purpose - The high expression of positive regulatory domain zinc finger protein2 (PRDM2) is an important factor in inducing the formation and progression of gastric cancer. The current study was performed to explore the effect of micro-RNA-362 (miR-362) targeting PRDM2 on the proliferation and apoptosis of gastric cancer cells. Methods - The expression of miR-362 in gastric adenocarcinoma and normal gastric mucosa was detected by real-time fluorescence quantitative PCR (qPCR), and the expression of PRDM2 in gastric adenocarcinoma was detected by im-munohistochemical method. Gastric cancer cell line MGC-803 and human normal gastric mucosal epithelial cell line (GES-1) were selected for study. Blank control group, empty vector transfection group, miR-362 transfection group, and miR-362 and PRDM2 co-transfection group were established. CCK-8 assay was utilized to detect cell activity, flow cytometry was used to detect cell cycle and apoptosis, and invasion capability of cells was observed through transwell experiment. The expression of Cyclin D1 and Caspases-3 was detected by western blot method. Results - The expression of miR-362 in gastric adenocarcinoma was significantly lower than that in normal gastric mucosa. The expression of miR-362 in gastric adenocarcinoma was significantly different in the maximum diameter, depth of invasion, and different TNM stages. The expression of miR-362 was linked to prognosis. In addition, there was a negative correlation between miR-362 and PRDM2. The expression of miR-362 in gastric cancer cell line MGC-803 was significantly lower than that in GES-1. Compared with the blank control group and empty vector transfection group, the proliferation level of gastric cancer cells in miR-362 transfection group was remarkably decreased, the cells in S phase and G2/M phase were significantly decreased, the capability for invasion was evidently decreased, while the apoptosis was significantly increased. The expression of Caspases-3 increased significantly and the expression of Cyclin D1 decreased significantly. MiR-362 and PRDM2 co-transfection groups could reverse the abovementioned expression levels. Conclusion - MiR-362 can regulate the proliferation, invasion and apoptosis of gastric cancer by inhibiting the expression of tumor-promoting factor PRDM2. The expression of miR-362 in gastric adenocarcinoma is significantly decreased, which can regulate the formation and development of gastric adenocarcinoma by promoting the expression of PRDM2. Moreover, low expression of miR-362 in gastric adenocarcinoma is an important risk factor for tumor progression and poor prognosis.

Screening and analysis of xanthine oxidase inhibitors in jute leaves and their protective effects against hydrogen peroxide-induced oxidative stress in cells

AbstractJute (Corchorus capsularis L.) is an annual herb of the bast fiber plant and has great potentials in food and medicinal usages because of its various bioactivities. In this study, ultrafiltration coupled with high-performance liquid chromatography-mass spectrometry was established for screening xanthine oxidase inhibitors from the jute leaves extract. Under the optimum screening conditions, three inhibitors were successfully screened and identified as chlorogenic acid, echinacoside, and isorhamnetin-rutinoside with UV and MS data. The fluorescent quenching analysis showed that three inhibitors quenched the fluorescence intensities of enzyme with different binding capacities. For further exploring the bioactivity of three inhibitors, the protective effects on hydrogen peroxide-induced oxidative stress was investigated using human normal liver cell (LO2), human gastric mucosal epithelial cell (GES-1), and human umbilical vein endothelial cell (HUVEC). As a result, they exhibited protective effects on three injured cells in dose-dependent manners without cytotoxicity. To evaluate the difference among different jute species obtained in our laboratories, the amounts of three compounds in ten samples were assessed and analyzed. The results showed that it could be divided into three groups. The jute leaves showed nutrient and medical potentials and deserved further research on pharmaceutical and biochemical utilization in future.

Pyruvate Kinase M2 Knockdown Suppresses Migration, Invasion, and Epithelial-Mesenchymal Transition of Gastric Carcinoma via Hypoxia-Inducible Factor Alpha/B-Cell Lymphoma 6 Pathway.

Gastric carcinoma is a common malignant cancer. Pyruvate kinase M2 (PKM2) is highly expressed in cancers, including gastric carcinoma. However, its function and molecular mechanism in gastric carcinoma remains unclear. Here, we aimed to explore the function and the underlying mechanism of PKM2 on malignant phenotypes in gastric carcinoma. In this study, the mRNA levels and protein levels of PKM2 in gastric carcinoma cell lines and normal gastric mucosa epithelial cell lines were detected using quantitative real-time PCR and western blot, respectively. PKM2 was downregulated by siRNA transfection. HIF-1α or BCL-6 was upregulated by corresponding overexpression plasmid. Cell viability was detected using CCK-8 assay. Cell invasion and migration were determined using transwell assay. Higher expression of PKM2 was observed in human gastric carcinoma cell lines MKN-45 and SGC-7901 than in the normal gastric mucosa epithelial cell line GES-1. PKM2 knockdown suppressed cancer cell invasion and migration and inhibited the epithelial-mesenchymal transition (EMT) phenotype by inhibiting E-cadherin and promoting vimentin and N-cadherin expression. Also, we observed that PKM2 knockdown suppressed the hypoxia-inducible factor alpha (HIF-1α) and B-cell lymphoma 6 (BCL-6) signaling pathway. HIF-1α overexpression reversed the function of PKM2 silencing on cell invasion, migration, EMT, and BCL-6 expression. BCL-6 overexpression also reversed the function of PKM2 silencing on cell invasion, migration, and EMT but did not affect HIF-1α expression. Taken together, data from our study suggest that PKM2 knockdown impeded cell migration, invasion, and EMT of gastric carcinoma cells via the HIF-1α/BCL-6 pathway.

Prognostic Value of Autophagy-related Proteins in Human Gastric Cancer

PurposeAutophagy-related proteins (ATG) play a crucial role in autophagy. Recently, the functions of autophagy in cancer have been gathering attention. However, the prognostic value of ATGs in gastric cancer (GC) has not been explored.MethodsThe Kaplan–Meier plotter (KM plotter) online database was used to examine the value of ATGs gene expression levels in overall survival (OS) prediction in GC patients with different clinical stage, differentiation, gender, HER2 status, and therapeutic strategy. In vitro experiments applied VE-822, an effective GC treatment, to assess cell migration and proliferation in gastric mucosa epithelial cells, and real-time PCR was used to measure alterations of autophagy-related gene expression.ResultsHigh ATG3, ATG4C, ATG5, and ATG10 mRNA levels were associated with good OS, while increased ATG4B, ATG7, ATG12, ATG16L1, and TECPR1 mRNA levels related to unfavorable OS in patients with GC. ATG12 overexpression had different effects on OS due to high levels of heterogeneity. High ATG12 expression was correlated with good OS in female patients with GC and with bad OS for male patients. Additionally, the increased ATG12 expression was more likely to get a satisfactory OS in patients who underwent surgery alone but was associated with poor OS for patients treated with 5-FU adjuvant. In addition, elevated TECPR1 expression was related to favorable OS for patients with poorly differentiated type, while for patients with moderate differentiation, it was relevant to poor OS. The in vitro experiments showed that berzosertib could significantly inhibit the migration and proliferation of human gastric mucosa epithelial cells, and further real-time PCR assessment of ATG expressions partially coincided with the bioinformation analysis above.ConclusionThese results indicate that individual ATGs have unique prognostic significance interpreted using Kaplan–Meier plotter analysis and in vitro experiments, and this may help guide clinical therapeutic strategy and promote OS by individualizing therapy for GC patients.

Crocin reverses 1-methyl-3-nitroso-1-nitroguanidine (MNNG)-induced malignant transformation in GES-1 cells through the Nrf2/Hippo signaling pathway.

Crocin, an active constituent of saffron, has anticancer activity. In this study, we investigated the relationship of Crocin with human gastric epithelial cells induced by 1-methyl-3-nitroso-1-nitroguanidine (MNNG), and explored the underlying mechanism. In vivo, the animal growth and atypical hyperplasia were observed in Sprague-Dawley rats. A cell model was established by treating the human gastric mucosa epithelial cell line GES-1 with MNNG. The effects of Crocin on proliferation, cell cycle, apoptosis, and epithelial-mesenchymal transition (EMT) in GES-1 cells were analyzed using Cell Counting Kit-8, colony formation, flow cytometry, and Transwell assay, respectively. Western blot was used to explore the potential mechanism.. The gastric mucosa of animal model deteriorated obviously, the weight growth rate slowed down, and the atypical hyperplasia of gastric mucosa increased. The GES-1 cells had characteristics of malignant cells such as proliferation, apoptosis, and metastasis ability. It was found that Crocin suppressed the cell proliferation, increased apoptosis, and blocked the cycle arrest in G0/G1 phase simultaneously. Furthermore, Crocin negatively regulated the invasion ability of MNNG-treated GES-1 cells and EMT process. Crocin also increased the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1), decreased TAZ in MNNG-treated GES-1 cells. Interestingly, Crocin regulated the expression of TAZ and yes-associated protein (YAP) by increasing Nrf2 level, as well as their upstream targets, mercaptopyruvate sulfurtransferase (MST) and large tumor suppressor (LATS). Crocin protected against MNNG-induced malignant transformation through the Nrf2/Hippo signaling pathway, which might be a drug candidate for clinical gastric cancer management.

MiR-212 as potential biomarker suppresses the proliferation of gastric cancer via targeting SOX4.

BackgroundCirculating microRNAs that post‐transcriptionally regulate gene expressions have been reported as promising biomarkers in cancer monitoring. This study was to identify the potential role of circulating miR‐212 in gastric cancer and whether it could serve as a novel biomarker for gastric cancer.MethodsWe detected the serum levels of miR‐212 in 100 health people and 110 gastric cancer patients and analyzed the relationships of the serum level of miR‐212 with gastric cancer. We detected the expression of miR‐212 in human gastric mucosal epithelial cell line (GES‐1) and human gastric cancer cell lines (NCI‐N87 and SNU‐16) using qRT‐PCR. Then, we detected the role of 5‐aza‐deoxycytidine on the epigenetic regulation of miR‐212 in human gastric cancer cell lines. Furthermore, luciferase reporter assay was used to detect binding activity of miR‐212 on SOX4 mRNA, and their functions on the cell proliferation and apoptosis.ResultsThe expression of miR‐212 was higher in health people than that in gastric cancer patients, higher in gastric mucosal epithelial cell line than that in gastric cancer cells. miR‐212 can be a circulating biomarker and an independent prognostic factor of gastric cancer. Moreover, miR‐212 can directly regulate the 3′UTR of SOX4 mRNA to suppress p53 and Bax, resulting gastric cancer cells proliferation inhibition and apoptosis induction.ConclusionOur study demonstrated that miR‐212 was epigenetically downregulated in gastric cancer, and resulting low level of miR‐212 can be a potential circulating biomarker and poor prognosis predicator of gastric cancer.

Research strategy thoughts about acupuncture-moxibustion treatment of chronic atrophic gastritis by suppressing apoptosis via circular RNA

Chronic atrophic gastritis (CAG) is a common digestive disease in clinic. Previous experimental and clinical studies have shown that acupuncture has a positive effect for CAG. Apoptosis of gastric mucosal tissue has been shown to play an important role in the process of gastric atrophy and possibly further carcinogenesis in CAG, and the circular RNA (circRNA), a novel class of non-coding RNA, has been confirmed to play a regulatory role in the downstream pathway of apoptosis by many stu-dies. Accumulated findings of experimental studies showed that acupuncture and moxibustion interventions could suppress apoptosis of the cultured human gastric mucosal epithelial cells and lower apoptotic index of gastric mucosal cells in CAG rats. Therefore, circRNA is likely to mediate the inhibitory effect of acupuncture and moxibustion on apoptosis of gastric mucosal epithelial cells in CAG. In this paper, we systematically summarized 1) the regulation of circRNA on apoptosis, 2) the apoptosis and pathological mechanism of CAG, 3) the effect of acupuncture on apoptosis, and proposed that circRNA is highly likely to be involved in the positive effect of acupuncture and moxibustion interventions for CAG. It is recommended that researches should further reveal the scientific basis of acupuncture and moxibustion therapies in the treatment of CAG by exploring the role of related circRNAs and their downstream target proteins in the gastric mucosal tissues.

Abstract 5183: The preclinical characterization of TST001, a novel humanized anti-claudin18.2 mAb with enhanced binding affinity and anti-tumor activity

Abstract Claudin-18 isoform 2 (CLDN18.2) is a member of the human claudin family of tetraspan membrane proteins that are crucial structural and functional components of tight junctions. Unlike other family members, CLDN18.2 expression is strictly limited to differentiated epithelial cells of gastric mucosa. Interestingly CLDN18.2 was ectopically expressed at a significant level in multiple tumor types including gastric, esophageal, pancreatic and lung cancers, which makes it as an attractive anti-cancer target. TST001 is a novel humanized IgG1 monoclonal antibody, which specifically binds to cells expressing human CLDN18.2 with high affinity but not to the closely related Claudin 18.1. TST001 can compete with IMAB362, the clinical stage anti-CLDN18.2 mAb, for its binding to CLDN18.2 yet engages distinct epitope for binding. By reducing fucosylation during cell culture process, TST001 has further enhanced binding affinity to FcγRIIIa, which translates into more potent ADCC activity. Indeed, TST001 showed sub-nanomolar ADCC activity against gastric cancer cells expressing medium to low CLDN18.2 in the presence of human PBMC and NK cells, which is significantly more potent than IMAB362. TST001 also showed more potent CDC and ADCP activities against CLDN18.2 expressing cells than IMAB362. In both Sprague Dawley Rat and Cynomolgus Monkey, the systemic exposure of TST001 increased proportionally in a dose-dependent manner. In gastric cancer cell line and patient derived xenograft tumor models, TST001 showed more potent anti-tumor activity as compared with IMAB362. Furthermore, the combination of TST001 with chemo agents resulted in synergistic anti-tumor effect in these tumor models. In addition, we have also generated and characterized an antibody that is suitable for IHC based detection and is selective to CLDN18.2 over CLDN18.1. Altogether, these preclinical findings warrant further clinical evaluation of TST001 in patients with CLDN18.2 positive tumors. Citation Format: Fei Teng, Yi Gu, Hui Chai, Huanhuan Guo, Hongjun Li, Xiwen Wu, Xinlai Yao, Fei Xu, Lei Shi, Zhenzhi Yan, Xiaoli Zi, Zheng Dai, Timethy Liao, Lisa Zheng, Francis Fan, Zhen Li, Jerry Yang, Xueming Qian. The preclinical characterization of TST001, a novel humanized anti-claudin18.2 mAb with enhanced binding affinity and anti-tumor activity [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5183.

A low toxic CRM1 degrader: Synthesis and anti-proliferation on MGC803 and HGC27.

Chromosome region maintenance 1 (CRM1) is the sole nuclear exporter of several tumor suppressor, a growth regulatory protein as an attractive cancer drug target. In the present work, a novel CRM1 degrader was discovered from newly synthesized α, β-unsaturated-δ-lactone based on a natural product Goniothalamin. It induces apoptosis of both MGC803 and HGC27cell lines via degrading CRM1. Selective inhibition was observed for the proliferation of gastric cancer cell lines MGC803, HGC27 comparing to Human Gastric Mucosal Epithelial Cell Line (GES1). For the first time, CRM1 inhibitor or degrader inducing apoptosis in gastric carcinoma was investigated.

Expression of thioredoxin reductase 1 (TrxR1) in gastric cancer and its effect on the growth of gastric cancer cells

To investigate the relationship between the expression of thioredoxin reductase 1 (TrxR1) in gastric cancer tissues and the survival time of patients with gastric cancer and its effect on the growth of gastric cancer cells. The expression level of TrxR1 mRNA in gastric cancer tissues and adjacent tissues of 76 patients was determined by real-time PCR assays, and the relationship between the mRNA expression level of TrxR1 and the clinicopathological characteristics and prognosis of gastric cancer patients was analyzed. Three gastric cancer tissues and adjacent tissues were randomly selected, and the expression of TrxR1 protein was detected by immunohistochemistry and Western blot. The expression levels of TrxR1 in human gastric cancer cells line and gastric mucosa epithelial cells were determined by Western blot and quantitative real-time PCR assays. Then, AGS cells were transfected with siRNA sequences to silence the expression of TrxR1. AGS cells were divided into 3 groups according to different processing negative control group: transfected with NC-siRNA, TRXR1 siRNA interference group 1: transfected with TRXR1-siRNA1, TRXR1 siRNA interference 2 group: transfected with TRXR1-siRNA2. The expression of TrxR1 mRNA in AGS cells of each group was detected by Real-time PCR. The proliferation of AGS cells was determined by MTT and colony formation assays following TrxR1 silencing. TrxR1 mRNA and protein expression levels in gastric cancer tissues were significantly up-regulated compared with adjacent tissues, and were mainly located in the cytoplasm. High expression of TrxR1 was associated with TNM stage and lymph node metastasis, and the overall survival time of patients with high expression of TrxR1 was shorter than those with low expression level. TrxR1 mRNA and protein in AGS cells of TRXR1-siRNA1 group and AGS cells of TRXR1-siRNA2 group were significantly reduced compared with NC-siRNA group (P＜0.05). And AGS cell clone formation and proliferation ability were decreased. The high expression of TrxR1 in gastric cancer tissues indicates poor prognosis of patients, and the silencing of TrxR1 can inhibit the proliferation of gastric cancer cells.

Hedgehog signaling activation required for glypican-6-mediated regulation of invasion, migration, and epithelial-mesenchymal transition of gastric cancer cells.

Gastric cancer (GC) is the fifth most common cancer worldwide and one of the most aggressive cancers in China. Glypican 6 is highly expressed in gastric adenocarcinoma and may act as a diagnostic and prognostic marker; however, the functional importance and molecular mechanism of glypican 6 in GC remains unclear. In the current study, we aimed to reveal the function and mechanism of glypican 6 in two GC cell lines: MKN-45 and SGC-7901. We found higher expression of glypican 6 in MKN-45 and SGC-7901 cells than in cells from the normal gastric mucosa epithelial cell line GES-1. Glypican 6 knockdown suppressed MKN-45 and SGC-7901 cell proliferation. A Transwell assay confirmed that glypican 6 silencing inhibited the migration and invasiveness of MKN-45 and SGC-7901 cells. Epithelial-to-mesenchymal transition (EMT) markers were determined by western blotting, and the results showed reduced Vimentin expression and elevated E-cadherin expression in glypican 6 short interfering RNA (siRNA) transfected MKN-45 and SGC-7901 cells. However, glypican 6 overexpression in GES-1 cells showed no significant promotion on GES-1 cells proliferation and migration. Further studies confirmed that glypican 6 siRNA regulated Hedgehog and Gli1 signaling and participated in the function of glypican 6 on MKN-45 and SGC-7901 cell migration and invasion. Our findings suggest that decreased glypican 6 expression inhibits the migration and invasion ability of GC cells.