Growth Of Gastric Cancer Cells Research Articles

Gastric cancer cell-derived exosomal miR-541-5p induces M2 macrophage polarization through DUSP3/JAK2/STAT3 pathway

PurposeExosomal microRNAs have been identified as important mediators of communication between tumor cells and macrophages in the microenvironment. miR-541-5p was reported to be involved in hepatocellular carcinoma progression, but its role in gastric cancer (GC) and in GC cell-macrophage crosstalk is unknown.MethodsCell proliferation, migration and invasion were respectively assessed by CCK-8 assay, scratch and Transwell assays. RT-qPCR was used to detect the level of miR-541-5p, macrophage markers and DUSP3. The percentage of CD11b+CD206+ cell population was analyzed by flow cytometry. Western blotting was employed to evaluate DUSP3-JAK2/STAT3 pathway proteins and exosome markers. The interaction between miR-541-5p and DUSP3 was verified by luciferase assay.ResultsThe results showed that miR-541-5p was upregulated in GC tissues and cells, and stimulated GC cell growth, migration and invasion in vitro. GC cells induce M2 macrophage polarization by secreting the exosomal miR-541-5p. Exosomal miR-541-5p maintained JAK2/STAT3 pathway activation in macrophages by targeting negative regulation of DUSP3. Inhibiting miR-541-5p significantly limited tumor growth in vivo.ConclusionIn conclusion, miR-541-5p promotes GC cell progression. GC cells may induce macrophage M2 polarization through the exosomal miR-541-5p-mediated DUSP3/JAK2/STAT3 pathway. miR-541-5p may be a potential therapeutic target for GC.

RHBDD1 Promotes the Growth and Stemness Characteristics of Gastric Cancer Cells by Activating Wnt/β-catenin Signaling Pathway.

Gastric cancer (GC) is threatening public health, with at least one million new cases reported each year. Rhomboid domain-containing protein 1 (RHBDD1) has been identified to regulate the proliferation, migration, and metastasis of cancer cells. However, the role of RHBDD1 in GC has not been elucidated. This study aimed to investigate the role of RHBDD1 on the growth, metastasis, and stemness characteristics of GC. RHBDD1 expression was analyzed from the TCGA databank. qRT-PCR was conducted to evaluate the transcription level of RHBDD1. Western blots were used to evaluate the protein expression of RHBDD1, CD133, CD44, Nanog, β-catenin and c-myc. Colony formation assay and transwell assay were conducted to evaluate the growth and metastasis of NCI-N87 cells, respectively. Sphere-forming assay was performed to study the stemness characteristics. The nude mice xenotransplantation model and immunohistochemistry (IHC) were performed to evaluate the growth of GC in vivo. Results: RHBDD1 expression is elevated in GC cells and clinical tissues. RHBDD1 expression is positively associated with cell proliferation and metastasis of GC cells. RHBDD1 knockdown suppresses the expression of CD133, CD44 and Nanog and attenuates sphere-forming ability. RHBDD1 activates the Wnt/β-catenin pathway via promoting the expression of β-catenin / c-myc and inducing β-catenin translocation into nuclear. RHBDD1 knockdown inhibits the growth of GC in nude mice xenotransplantation model. RHBDD1 is highly expressed in GC, and its knockdown inhibits the growth, metastasis and stemness characteristics of GC cells through activating the Wnt/β-catenin pathway, suggesting that RHBDD1 has the potential to be a novel therapeutic target for GC treatment.

Discovery of the Natural Bibenzyl Compound Erianin in Dendrobium Inhibiting the Growth and EMT of Gastric Cancer through Downregulating the LKB1-SIK2/3-PARD3 Pathway.

Erianin, a bibenzyl compound found in dendrobium extract, has demonstrated broad anticancer activity. However, its mechanism of action in gastric cancer (GC) remains poorly understood. LKB1 is a tumor-suppressor gene, and its mutation is an important driver of various cancers. Yet some studies have reported contradictory findings. In this study, we combined bioinformatics and in vitro and in vivo experiments to investigate the effect and potential mechanism of Erianin in the treatment of GC. The results show that LKB1 was highly expressed in patients' tumor tissues and GC cells, and it was associated with poor patient prognosis. Erianin could promote GC cell apoptosis and inhibit the scratch repair, migration, invasion, and epithelial-mesenchymal transition (EMT) characteristics. Erianin dose-dependently inhibited the expression of LKB1, SIK2, SIK3, and PARD3 but had no significant effect on SIK1. Erianin also inhibited tumor growth in CDX mice model. Unexpectedly, 5-FU also exhibited a certain inhibitory effect on LKB1. The combination of Erianin and 5-FU significantly improved the anti-tumor efficacy of 5-FU in the growth of GC cells and xenograft mouse models. In summary, Erianin is a potential anti-GC compound that can inhibit GC growth and EMT properties by targeting the LKB1-SIK2/3-PARD3-signaling axis. The synergistic effect of Erianin and 5-FU suggests a promising therapeutic strategy for GC treatment.

Envafolimab Inhibits the Growth of Gastric Cancer Cells with Low PD-L1 Expression through the DDX20/NF-κB/TNF-α Signaling Pathway.

The mechanism of action of envafolimab (also known as KN035), a programmed death ligand 1 (PD-L1) inhibitor, in gastric adenocarcinoma patients with low PD-L1 expression is not well understood. This study aimed to observe the efficacy of envafolimab in gastric adenocarcinoma with low PD-L1 expression and explore the underlying mechanisms. The objective of this study was to explore the underlying mechanism of envafolimab in gastric cancer with low PD-L1 expression. Cytotoxicity and proliferation were evaluated by a CCK8 assay. Transwell assays were used to detect the migration and invasion ability of gastric cancer cells. The effect of envafolimab on the apoptosis of gastric cancer cells was detected by flow cytometry. The effect of envafolimab on gastric cancer cells with low PD-L1 expression was investigated via proteomics and bioinformatics analysis. A total of 19 patients with advanced gastric adenocarcinoma who received envafolimab monotherapy or combination therapy were reviewed. Among them, 4 patients had low PD-L1 expression, the objective response rate (ORR) was 75% (3/4), and the disease control rate (DCR) was 100% (4/4). In vitro experiments showed that envafolimab inhibited the proliferation, invasion, and migration of gastric cancer cells with low expression of PD-L1 and induced cell apoptosis. DDX20 may be the target of envafolimab in gastric cancer cells, and it is related to the NF-κB signaling pathway. Western blot results showed that the protein expressions of DDX20, NF-κB p65, and TNF-α in gastric cancer cells were decreased after adding envafolimab. Furthermore, the DDX20 gene was silenced by small interfering RNA to further study the effect of DDX20 on PDL1 low expression in gastric cancer cells. This study confirmed that envafolimab could inhibit the growth of gastric cancer cells with low PD-L1 expression by down-regulating DDX20 expression and regulating the NFκB/TNF-α signaling pathway.

Gastrokine 1 transferred by gastric cancer exosomes inhibits growth and invasion of gastric cancer cells in vitro and in vivo

AbstractIn gastric cancer, gastrokine 1 (GKN1) is a potential theragnostic marker while the related mechanisms remain elusive. Exosomes mediate intercellular communications via transferring various molecules, yet there are limited research studies on the specific cargos of gastric cancer exosomes and the associated mechanisms in this disease. In the present study, AGS and N87‐C cells were transfected with an overexpressed GKN1 plasmid, followed by extraction of exosomes. The study utilized gastric cancer cell lines and a xenograft mouse model to investigate the functional significance of exosomal GKN1. Cell proliferation, metastasis, and apoptosis were assessed through CCK‐8, Transwell, and flow cytometry assays, respectively. The study further explored the mechanism of exosomal GKN1 and its interaction with the PI3K/AKT/mTOR signaling pathways, including immunofluorescence and western blot analyses. Exosomal GKN1 was observed to suppress cell proliferation and invasion while enhancing apoptosis. This effect was attributed to the modulation of key proteins involved in cellular processes, including Ki‐67, MMP‐9, Bcl‐2, Bax, caspase‐3, and caspase‐9, ultimately impacting the PI3K/AKT/mTOR signaling pathway. The findings suggest that exosomal GKN1 exerts inhibitory effects on gastric cancer cell growth and invasion through the regulation of the PI3K/AKT/mTOR signaling cascade, both in experimental cell cultures and animal models.

Anthocyanins and proanthocyanidins synergistically inhibit the growth of gastric cancer cells in vitro: exploring the potential physiological activity of grape and red wine

Red wine is rich in anthocyanins and procyanidins which possess multiple health-promoting properties. However, the synergistically anticancer effects of them on gastric cancer cells still undefined. The results showed that combination of malvidin-3-O-(6-O-coumaroyl)-glucoside-5-O-glucoside (M35GC) and procyanidin C1 could effectively inhibited the viability of MKN-28 cells with the lowest IC50 value. Mechanistically, M35GC and procyanidin C1 significantly induced cell apoptosis by reducing the ratio of Bcl-2/Bax, blocked cell cycle in G0/G1 phase by decreasing CDK4 protein and decreased glucose consumption and lactate production during aerobic glycolysis through suppressing the expression of HK2 protein in MKN-28 cells. In conclusion, induction of cell apoptosis and cell cycle arrest, as well as the inhibition of HK2 protein that participates in the glycolytic pathway and the suppression of aerobic glycolysis by M35GC and procyanidin C1 contributed to the anti-cancer effects in gastric cancer.

Synthesis and Anti-gastric Cancer Activity by Targeting FGFR1 Pathway of Novel Asymmetric Bis-chalcone Compounds

Backgroup: Bis-chalcone compounds with symmetrical structures, either isolated from natural products or chemically synthesized, have multiple pharmacological activities. Asymmetric Bis-chalcone compounds have not been reported before, which might be attributed to the synthetic challenges involved, and it remains unknown whether these compounds possess any potential pharmacological activities. Aims: The aim of this study is to investigate the synthesis route of asymmetric bis-chalcone compounds and identify potential candidates with efficient anti-tumor activity. Method: The two-step structural optimization of the bis-chalcone compounds was carried out sequentially, guided by the screening of the compounds for their growth inhibitory activity against gastric cancer cells by MTT assay. The QSAR model of compounds was established through random forest (RF) algorithm. The activities of the optimal compound J3 on growth inhibition, apoptosis, and apoptosis-inducing protein expression in gastric cancer cells were investigated sequentially by colony formation assay, flow cytometry, and western blotting. Further, the inhibitory effects of J3 on the FGFR1 signaling pathway were explored by Wester Blotting, siRNA, and MTT assays. Finally, the in vivo anti-tumor activity and mechanism of J3 were studied through nude mouse xenograft assay, western blotting. Result: 27 asymmetric bis-chalcone compounds, including two types (N and J) were sequentially designed and synthesized. Some N-class compounds have good inhibitory activity on the growth of gastric cancer cells. The vast majority of J-class compounds optimized on the basis of N3 exhibit excellent inhibitory activity on gastric cancer cell growth. We established a QSAR model (R2 = 0.851627) by applying random forest algorithms. The optimal compound J3, which has better activity, concentration-dependently inhibited the formation of gastric cancer cell colonies and led to cell apoptosis by inducing the expression of the pro-apoptotic protein cleaved PARP. J3 may exert anti-gastric cancer effects by inhibiting the activation of FGFR1/ERK pathway. Moreover, at a dose of 10 mg/kg/day, J3 inhibited tumor growth in nude mice by nearly 70% in vivo with no significant toxic effect on body weight and organs. Conclusion: In summary, this study outlines a viable method for the synthesis of novel asymmetric bischalcone compounds. Furthermore, the compound J3 demonstrates substantial promise as a potential candidate for an anti-tumor drug.

LncRNA EGOT and tumorigenesis via Hedgehog pathway in gastric cancer.

e16130 Background: Gastric cancer (GC) is one of the mostly terminal malignancies with poor prognosis. Long noncoding RNA EGOT (EGOT) acts as a crucial regulator in the breast cancer. However, the function of EGOT in GC remains unknown. Methods: This work was to explore the clinical value and biological significance of EGOT in GC. EGOT levels in GC tissue and cell were analyzed by qRT–PCR. After knockdown of EGOT, GC cell growth and cycle progression were detected. Results: The expression of EGOTwas observably elevated in GC. Upregulation of EGOT was related with lymphatic metastasis and TNM stage. In addition, knockdown of EGOT by siRNA could significantly inhibit GC cell proliferation and arrest cycle progression in G1 phase. Moreover, EGOT mediated cyclin D1 expression in GC cells which was regulated by Hedgehog pathway. Further, loss of EGOT downregulated Hedgehog signaling pathway in GC cells. Conclusions: EGOT functions as an oncogene in GC, and may be useful as a conceivable diagnostic and prognostic biomarker for GC tumorigenesis.

LncRNA EGOT and tumorigenesis via Hedgehog pathway in gastric cancer.

e16130 Background: Gastric cancer (GC) is one of the mostly terminal malignancies with poor prognosis. Long noncoding RNA EGOT (EGOT) acts as a crucial regulator in the breast cancer. However, the function of EGOT in GC remains unknown. Methods: This work was to explore the clinical value and biological significance of EGOT in GC. EGOT levels in GC tissue and cell were analyzed by qRT–PCR. After knockdown of EGOT, GC cell growth and cycle progression were detected. Results: The expression of EGOTwas observably elevated in GC. Upregulation of EGOT was related with lymphatic metastasis and TNM stage. In addition, knockdown of EGOT by siRNA could significantly inhibit GC cell proliferation and arrest cycle progression in G1 phase. Moreover, EGOT mediated cyclin D1 expression in GC cells which was regulated by Hedgehog pathway. Further, loss of EGOT downregulated Hedgehog signaling pathway in GC cells. Conclusions: EGOT functions as an oncogene in GC, and may be useful as a conceivable diagnostic and prognostic biomarker for GC tumorigenesis.

Naringenin-Loaded Bovine Serum Albumin Nanoparticles Inhibit Reactive Oxygen Species (ROS) to Prevent Ulcer and Gastric Cancer

Gastric cancer is a malignance of digestive system and effective treatment measures are key to treatment of gastric cancer. In this experiment, we assessed the effect of bovine serum albumin nanoparticle (BASNP)-coated naringenin (NGN) on reactive oxygen species (ROS) in gastric cancer. After preparation of NGN-BASNP and animal model of gastric cancer, rats were administered with NGN-BASNP, ROS agonists and ROS inhibitors, when the model group was set. After one week of intervention, gastric ulcers in rats were measured and Hematoxylin-eosin (HE) staining was performed. Transwell chamber was used to detect cell invasion ability, while 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was detected proliferation ability of gastric cancer cells. Real Time Quantitative Polymerase Chain Reaction (RT-qPCR) and Western blot determined TNF-α mRNA expression and ROS. With about 100 nm diameter of NGN-BASNP nanoparticles, the nanoparticles presented in good shape. Compared with lesions in the model group, NGN-BASNP treatment greatly improved the condition, relieving the ulcer and decreasing the ulcer area (P < 0.05). After adding ROS agonist, inhibitory effect of NGN-BASNP intervention was amplified (P < 0.01) when the ROS level in the NGN-BASNP+ROS agonist group was decreased and TNF-α expression decreased. Moreover, NGN-BASNP effectively suppressed gastric cancer cell proliferation and migration but induced apoptosis. NGN-BASNP inhibited the expression of TNF-α mRNA and ROS level in gastric cancer cells, thereby alleviating gastric ulcer and delaying gastric cancer cell growth.

Sulforaphane impaired immune checkpoint blockade therapy through activating ΔNP63α/PD-L1 axis in gastric cancer.

Sulforaphane (SFN) exerts anticancer effect on various cancers including gastric cancer. However, the regulatory effect of SFN on programmed death-ligand 1 (PD-L1) and checkpoint blockade therapy in gastric cancer have not been elucidated. Here we demonstrated that SFN suppressed gastric cancer cell growth both in vitro and in vivo study. SFN upregulated PD-L1 expression through activating ΔNP63α in gastric cancer cells. Further, we found that SFN impaired the anticancer effect of anti-PD-L1 monoclonal antibody (α-PD-L1 mab) on gastric cancer cells. These results uncover a novel PD-L1 regulatory mechanism and the double-edged role of SFN in gastric cancer intervention.

Cystatin SA attenuates gastric cancer cells growth and increases sensitivity to oxaliplatin via PI3K/AKT signaling pathway

PurposeCystatin SA (CST2) belongs to the superfamily of cysteine protease inhibitors. Emerging research indicates that CST2 is often dysregulated across various cancers. Its role and molecular mechanisms in gastric cancer remain underexplored. This study aims to explore the expression and function of CST2 in gastric cancer.MethodsCST2 expression was analyzed and validated through Western blot. CST2 overexpression was induced by lentivirus in GC cells, and the correlation between CST2 expression levels and downstream signaling pathways was assessed. In addition, multiple assays, including cell proliferation, colony formation, wound-healing, and transwell migration/invasion, were considered to ascertain the influence of CST2 overexpression on gastric cancer. The cell cycle and apoptosis were detected by flow cytometry.ResultsCST2 expression at the protein level was decreased to be reduced in both gastric cancer tissues and cell lines, and CST2 expression attenuate gastric cancer growth, an effect restricted to gastric cancer cells and absent in gastric epithelial GES-1 cells. Furthermore, CST2 was demonstrated to improve chemosensitivity to Oxaliplatin in gastric cancer cells through the PI3K/AKT signaling pathway.ConclusionThese findings indicate that CST2 is downregulated at the protein level in gastric cancer tissues and cell lines. Additionally, CST2 was found to attenuate the growth of gastric cancer cells and to enhance sensitivity to Oxaliplatin through the PI3K/AKT signaling pathway, specific to gastric cancer cell lines. CST2 may serve as a tumor suppressor gene increasing sensitivity to Oxaliplatin in gastric cancer.

SNHG15-mediated feedback loop interplays with HNRNPA1/SLC7A11/GPX4 pathway to promote gastric cancer progression.

Dysregulation of long noncoding RNA (lncRNA) expression plays a pivotal role in the initiation and progression of gastric cancer (GC). However, the regulation of lncRNA SNHG15 in GC has not been well studied. Mechanisms for ferroptosis by SNHG15 have not been revealed. Here, we aimed to explore SNHG15-mediated biological functions and underlying molecular mechanisms in GC. The novel SNHG15 was identified by analyzing RNA-sequencing (RNA-seq) data of GC tissues from our cohort and TCGA dataset, and further validated by qRT-PCR in GC cells and tissues. Gain- and loss-of-function assays were performed to examine the role of SNHG15 on GC both invitro and invivo. SNHG15 was highly expressed in GC. The enhanced SNHG15 was positively correlated with malignant stage and poor prognosis in GC patients. Gain- and loss-of-function studies showed that SNHG15 was required to affect GC cell growth, migration and invasion both invitro and invivo. Mechanistically, the oncogenic transcription factors E2F1 and MYC could bind to the SNHG15 promoter and enhance its expression. Meanwhile, SNHG15 increased E2F1 and MYC mRNA expression by sponging miR-24-3p. Notably, SNHG15 could also enhance the stability of SLC7A11 in the cytoplasm by competitively binding HNRNPA1. In addition, SNHG15 inhibited ferroptosis through an HNRNPA1-dependent regulation of SLC7A11/GPX4 axis. Our results support a novel model in which E2F1- and MYC-activated SNHG15 regulates ferroptosis via an HNRNPA1-dependent modulation of the SLC7A11/GPX4 axis, which serves as the critical effectors in GC progression, and provides a new therapeutic direction in the treatment of GC.

CircVDAC3 sequesters microRNA-592 and elevates EIF4E3 expression to inhibit the progression of gastric cancer

BackgroundAccumulating evidence has shown that circular RNAs (circRNAs) are involved in gastric cancer (GC) tumorigenesis. However, specific functional circRNAs in GC remain to be discovered, and their underlying mechanisms remain to be elucidated. MethodsCircRNAs that were differentially expressed between GC tissues and controls were analyzed using a circRNA microarray dataset. The expression of circVDAC3 in GC was determined using quantitative real-time PCR (qRT-PCR), and the structural features of circVDAC3 were validated. Cell function assays and animal experiments were conducted to explore the effects of circVDAC3 on GC. Finally, bioinformatics analysis, fluorescent in situ hybridization, and dual luciferase assays were used to analyze the downstream mechanisms of circVDAC3. ResultsOur results showed that circVDAC3 was downregulated in GC and inhibited the proliferation and metastasis of GC cells. Mechanistically, circVDAC3 acts as a competing endogenous RNA (ceRNA) of miR-592 and deregulates the repression of EIF4E3 by miR-592. EIF4E3 is downregulated in GC and overexpression of miR-592 or knockdown of EIF4E3 in circVDAC3-overexpressing cells weakens the anticancer effect of circVDAC3. ConclusionOur study provides evidence that circVDAC3 affects the growth and metastasis of GC cells via the circVDAC3/miR-592/EIF4E3 axis. Our findings offer valuable insights into the mechanisms underlying GC tumorigenesis and suggest novel therapeutic strategies.

The clinical significance of mitochondrial calcium uniporter in gastric cancer patients and its preliminary exploration of the impact on mitochondrial function and metabolism.

The objective of this study is to elucidate the influence of MCU on the clinical pathological features of GC patients, to investigate the function and mechanism of the mitochondrial calcium uptake transporter MCU in the initiation and progression of GC, and to explore its impact on the metabolic pathways and biosynthesis of mitochondria. The ultimate goal is to identify novel targets and strategies for the clinical management of GC patients. Tumor and adjacent tissue specimens were obtained from 205 patients with gastric cancer, and immunohistochemical tests were performed to assess the expression of MCU and its correlation with clinical pathological characteristics and prognosis. Data from TCGA, GTEx and GEO databases were retrieved for gastric cancer patients, and bioinformatics analysis was utilized to investigate the association between MCU expression and clinical pathological features. Furthermore, we conducted an in-depth analysis of the role of MCU in GC patients. We investigated the correlation between MCU expression in GC and its impact on mitochondrial function, metabolism, biosynthesis, and immune cells. Additionally, we studied the proteins or molecules that interact with MCU. Our research revealed high expression of MCU in the GC tissues. This high expression was associated with poorer T and N staging, and indicated a worse disease-free survival period. MCU expression was positively correlated with mitochondrial function, mitochondrial metabolism, nucleotide, amino acid, and fatty acid synthesis metabolism, and negatively correlated with nicotinate and nicotinamide metabolism. Furthermore, the MCU also regulates the function of the mitochondrial oxidative respiratory chain. The MCU influences the immune cells of GC patients and regulates ROS generation, cell proliferation, apoptosis, and resistance to platinum-based drugs in gastric cancer cells. High expression of MCU in GC indicates poorer clinical outcomes. The expression of the MCU are affected through impacts the function of mitochondria, energy metabolism, and cellular biosynthesis in gastric cancer cells, thereby influencing the growth and metastasis of gastric cancer cells. Therefore, the mitochondrial changes regulated by MCU could be a new focus for research and treatment of GC.

LncRNA RMST is associated with the progression and prognosis of gastric cancer via miR-204-5p

BackgroundExploring novel biomarkers for gastric cancer holds promise for enhancing patients’ therapy and survival rates. lncRNAs and miRNAs have emerged as important biomarkers for various human cancers. However, the role of lncRNA RMST (RMST) in gastric cancer development and the mechanism underlying its function remains unclear.ResultsSignificant upregulation of RMST was observed in gastric cancer tumor tissues. RMST levels showed strong correlation with patients’ lymph node metastasis and TNM stage and serving as a predictor of adverse prognosis RMST negatively regulated miR-204-5p, which in turn mediated the inhibitory effects of RMST knockdown on gastric cancer cell growth and metastasis.ConclusionRMST served as both a prognostic biomarker and tumor promoter by modulating miR-204-5p. Inhibiting RMST could represent a novel and potential therapeutic strategy for gastric cancer.

Integrated enhancer regulatory network by enhancer-promoter looping in gastric cancer.

Enhancer cis-regulatory elements play critical roles in gene regulation at many stages of cell growth. Enhancers in cancer cells also regulate the transcription of oncogenes. In this study, we performed a comprehensive analysis of long-range chromatin interactions, histone modifications, chromatin accessibility and expression in two gastric cancer (GC) cell lines compared to normal gastric epithelial cells. We found that GC-specific enhancers marked by histone modifications can activate a population of genes, including some oncogenes, by interacting with their proximal promoters. In addition, motif analysis of enhancer-promoter interacting enhancers showed that GC-specific transcription factors are enriched. Among them, we found that MYB is crucial for GC cell growth and activated by the enhancer with an enhancer-promoter loop and TCF7upregulation. Clinical GC samples showed epigenetic activation of enhancers at the MYB locus and significant upregulation of TCF7 and MYB, regardless of molecular GC subtype and clinicopathological factors. Single-cell RNA sequencingof gastric mucosa with intestinal metaplasia showed high expression of TCF7 and MYB in intestinal stem cells. When we inactivated the loop-forming enhancer at the MYB locus using CRISPRinterference (dCas9-KRAB), GC cell growth was significantly inhibited. In conclusion, we identified MYB as an oncogene activated by a loop-forming enhancer and contributing to GC cell growth.

YTHDF2 promotes gastric cancer progression and enhances chemoradiotherapy resistance.

The role of YTHDF2 in gastric cancer (GC) is controversial. Due to the limitations of technical difficulty and experimental period, research on completely knocking out YTHDF2 is rare. Therefore, further investigations are still needed to clarify the YTHDF2's clinical significance and biological function in GC. To carry out the investigation, an analysis was performed on the expression levels of YTHDF2 in both publicly available databases and samples obtained from patients with gastric cancer. Based on the complete knockout of YTHDF2 using the CRISPR-Cas9 system, in vivo and in vitro experiments were conducted to analyze the effects of YTHDF2 on tumor formation, radiotherapy and chemoradiotherapy resistance in GC. Our investigation revealed an increase in YTHDF2 levels in GC tissues, which was found to be associated with a negative prognosis. Under hypoxic conditions, high expression of YTHDF2 enhanced the invasion of gastric cancer cells, and high expression of YTHDF2 was associated with HIF-1a. YTHDF2 facilitated gastric cancer cell growth in vitro and in vivo. Moreover, the results of the present study demonstrated that YTHDF2 mediated the expression of CyclinD1 and stability of CyclinD1 mRNA. CyclinD1 knockdown inhibited YTHDF2-mediated GC cell proliferation whereas CyclinD1 overexpression ameliorated YTHDF2 knockdown-induced inhibition of GC progression. Furthermore, YTHDF2 also promoted resistance to DDP and CTX chemotherapy, along with radiotherapy treatment for GC cells. The findings suggested that YTHDF2 expression accelerated GC progression through a potential mechanism involving CyclinD1 expression, and enhanced chemoradiotherapy resistance. This indicated that YTHDF2 could be a promising prognostic biomarker and therapeutic target for individuals diagnosed with GC.

Exosomal circSTRBP from cancer cells facilitates gastric cancer progression via regulating miR-1294/miR-593-3p/E2F2 axis.

CircRNAs represent a new class of non-coding RNAs which show aberrant expression in diverse cancers, such as gastric cancer (GC). circSTRBP, for instance, is suggested to be overexpressed in GC cells and tissues. However, the biological role of circSTRBP in the progression of GC and the potential mechanisms have not been investigated. circSTRBP levels within GC cells and tissues were measured by RT-qPCR. The stability of circSTRBP was assessed by actinomycin D and Ribonuclease R treatment. Cell proliferation, migration, invasion and invitro angiogenic abilities after circSTRBP knockdown were analysed through CCK-8 assay, transwell culture system and the tube formation assay. The interaction of circSTRBP with the predicted target microRNA (miRNA) was examined by RNA immunoprecipitation and luciferase reporter assays. Xenograft tumour model was established to evaluate the role of exosomal circSTRBP in the tumour formation of GC cells. circSTRBP was upregulated in GC cells and tissues, and there was an increased level of circSTRBP in GC-derived exosomes. circSTRBP in the exosomes enhanced GC cell growth and migration invitro, which modulates E2F Transcription Factor 2 (E2F2) expression through targeting miR-1294 and miR-593-3p. Additionally, exosomal circSTRBP promoted the tumour growth of GC cells in the xenograft model. Exosomal circSTRBP is implicated in the progression of GC by modulating the activity of miR-1294/miR-593-3p/E2F2 axis.

Abstract 6003: The TNF-α-induced protein 3-interacting protein1 (TNIP1) suppresses HGF mediated NF-kB pathway activation and growth in gastric cancer cells

Abstract Background: TNF-α-induced protein 3-interacting protein 1 (TNIP1), an integral component in the regulation of immune responses and cellular pathways, is gaining increased attention in the scientific community. Its ability to interact with A20, a crucial ubiquitin-editing enzyme, forms a significant part of the body's mechanism to control inflammation and prevent unregulated immune responses, which are pivotal in the pathogenesis of autoimmune diseases. TNIP1's role extends beyond autoimmunity; it is also implicated in the regulation of cancer cell proliferation and survival, making it a potential target in cancer therapy. However, TNIP1 has not yet been elucidated on the tumorigenesis, proliferation, and invasion of human gastric cancer, and needs to be researched and discovered. In this study, the HGF-mediated association of TNIP1, nuclear factor kappa-B (NF-κB), and matrix metalloproteinase 9 (MMP9) and cancer cell proliferation and invasion were investigated in two types of human gastric cancer cell lines. Methods: In this study, cell culture, cDNA microarray analysis, western blotting, Real-Time Polymerase chain reaction, Zymography, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, TNIP1 knock-down with short hairpin RNA (shRNA), apoptosis, reagents and antibodies, standard two chamber invasion assay. Results: In our study on gastric cancer cells, we found that hepatocyte growth factor (HGF) stimulation altered TNIP1 expression at both mRNA and protein levels, indicating a dynamic interaction between HGF and TNIP1. The use of LY294002, a PI3K/AKT pathway inhibitor, revealed TNIP1's involvement in the NF-kB pathway, showing changes in NFkB and TNIP1 expression post-HGF stimulation. TNIP1-shRNA expressing cells exhibited altered expression of p53, BCL-2, NFkB, and MMP9, markers crucial for tumor progression and metastasis. Notably, TNIP1 knockdown led to increased cell proliferation and enhanced invasion capabilities in gastric cancer cells. Furthermore, TNIP1 knockdown cells showed a significant decrease in apoptosis rates upon HGF treatment, as confirmed by propidium iodide staining and FACS analysis. Conclusions: In conclusion, our results demonstrate that TNIP1 is closely associated with the NF-kB pathway and plays a critical role in modulating tumor invasion and apoptosis in gastric cancer cells. These findings suggest that TNIP1 could be a potential therapeutic target for the treatment of gastric cancer, providing new insights into the mechanisms of tumor progression and the development of targeted therapies. Citation Format: Jiyoon Jung, Sungae Koh, Kyunghee Lee. The TNF-α-induced protein 3-interacting protein1 (TNIP1) suppresses HGF mediated NF-kB pathway activation and growth in gastric cancer cells [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 6003.