Functions Of Gastric Cancer Cells Research Articles

Downregulation of short-stature homeobox protein 2 suppresses gastric cancer cell growth and stemness in vitro and in vivo via inactivating wnt/β-catenin signaling.

Gastric cancer (GC) a prevalent form of cancer globally. Previous research suggests that SHOX2 may have a role in promoting cancer progression. However, the role of SHOX2 in GC is not well understood. Based on data from TCGA_GC data set, SHXO2 levels were examined in normal and GC tissues. Patients in the TCGA_GC cohort were divided into high- and low-SHOX2 level groups for analysis of overall survival (OS), functional enrichment, and immune infiltration. Furthermore, experiments were conducted to investigate the impact of SHOX2 on GC cell function through gain- and loss-of-function experiments. Utilizing data from public databases, SHOX2 mRNA levels were found to be elevated in GC tissues compared to normal control, this finding was confirmed by RT-qPCR, western blot analysis, and immune-histochemical analyses. Elevated SHOX2 levels could serve as an independent indicator of poor prognosis in GC patients. Furthermore, SHOX2 levels had a negative correlation with CD8 T cells and CD4 memory activated T cells, and a positive correlation with of M0 macrophages in GC patients. Functional analyses revealed that SHOX2 deficiency notably suppressed GC cell proliferation, migration, and invasion. Additionally, SHOX2 deficiency was shown to suppress stemness in GC cells in vitro and in vivo via inactivating wnt/β-catenin signaling. Collectively, SHOX2 may serve as a prognostic marker for GC patients, and downregulation of SHOX2 could effectively impede GC cell growth and stemness by inactivating the wnt/β-catenin signaling pathway. These findings underscore the potential of SHOX2 as a promising therapeutic target for GC.

Putative Dual Roles of Bone Morphogenetic Protein 8B (BMP8B) in Disease Progression of Gastric Cancer.

Increased expression of bone morphogenetic protein 8B (BMP8B) in bone marrow and primary tumors of patients with gastric cancer (GC) is associated with disease progression and poor prognosis. However, a reduced expression has also been seen in GCs due to histone acetylation. This study aimed to evaluate BMP8B transcript levels in a large GC cohort and its impact on cellular functions. BMP8B transcripts were determined in 319 gastric tumors and compared with 182 adjacent normal tissues using real time PCR, with a further analysis conducted in the TCGA database. Kaplan-Meier plotter analysis was performed to evaluate the correlation between BMP8B and prognosis of the disease. BMP8B knockdown model was employed to determine the effect of BMP8B on the function of GC cells (HGC27). BMP8B mRNA levels were significantly up-regulated in the GC tissues compared with adjacent normal tissues in both TCGA database and our own database from Beijing Cancer Hospital, and high BMP8B expression was associated with poor prognosis. BMP8B is most likely to be involved in the differentiation of GC. Poorly differentiated GC samples presented a significantly reduced BMP8B expression in relation to well-differentiated and moderately differentiated GC. BMP8B knockdown inhibited proliferation of GC cells, while promoted invasion and migration of cancer cells. BMP8B was reduced in GCs, whereas higher BMP8B expression was associated with poor prognosis. BMP8B knockdown inhibited proliferation of GC cells, and promoted invasion and migration. Our results suggest that BMP8B plays dual roles in GC.

Expression and significant roles of the long non-coding RNA CASC19/miR-491-5p/HMGA2 axis in the development of gastric cancer

BACKGROUND Gastric cancer (GC) is a common malignant tumor, long non-coding RNA and microRNA (miRNA) are important regulators that affect tumor proliferation, metastasis and chemotherapy resistance, and thus participate in tumor progression. CASC19 is a new bio-marker which can promote tumor invasion and metastasis. However, the mechanism by which CASC19 affects the progression of GC through miRNA is not clear. AIM To explore the role of the CASC19/miR-491-5p/HMGA2 regulatory axis in GC. METHODS To explore the expression and prognosis of CASC19 in GC through clinical samples, and investigate the effects of inhibiting CASC19 on the proliferation, migration, invasion and other functions of GC cells through cell counting Kit-8 (CCK-8), ethynyldeoxyuridine, Wound healing assay, Transwell, Western blot and flow cytometry experiments. The effect of miR-491-5p and HMGA2 in GC were also proved. The regulatory relationship between CASC19 and miR-491-5p, miR-491-5p and HMGA2 were validated through Dual-luciferase reporter gene assay and reverse transcription PCR. Then CCK-8, Transwell, Wound healing assay, flow cytometry and animal experiments verify the role of CASC19/miR-491-5p/HMGA2 regulatory axis. RESULTS The expression level of CASC19 is related to the T stage, N stage, and tumor size of patients. Knockdown of the expression of CASC19 can inhibit the ability of proliferation, migration, invasion and EMT conversion of GC cells, and knocking down the expression of CASC19 can promote the apoptosis of GC cells. Increasing the expression of miR-491-5p can inhibit the proliferation of GC cells, miR-491-5p mimics can inhibit EMT conversion, and promote the apoptosis of GC cells, while decreasing the expression of miR-491-5p can promote the proliferation and EMT conversion and inhibit the apoptosis of GC cells. The expression of HMGA2 in GC tissues is higher than that in adjacent tissues. At the same time, the expression level of HMGA2 is related to the N and T stages of the patients. Reducing the level of HMGA2 can promote cell apoptosis and inhibit the proliferation of GC cells. Cell experiments and animal experiments have proved that CASC19 can regulates the expression of HMGA2 through miR-491-5p, thereby affecting the biological functions of GC. CONCLUSION CASC19 regulates the expression of HMGA2 through miR-491-5p to affect the development of GC. This axis may serve as a potential biomarker and therapeutic target of GC.

Retinol Binding Protein 4 Serves as a Potential Tumor Biomarker and Promotes Malignant Behavior in Gastric Cancer.

Gastric cancer (GC) is a highly phenotypically heterogeneous disease and is caused by a combination of factors. Retinol binding protein 4 (RBP4) is a member of a family of lipid transport proteins that are involved in the transport of substances between cells and play a crucial role in a variety of cancers. However, the expression and role of RBP4 in GC remain unknown. In this study, we explored the expression, prognostic significance, immune microenvironment, drug responsiveness and function of associated signaling pathways of RBP4 in GC using web-based bioinformatics tools. Immunohistochemistry and real-time quantitative PCR were utilized to analyze the tissue and cell expression levels of RBP4. CCK-8, colony formation, EDU incorporation, wound healing and transwell assays were applied to demonstrate the effect of RBP4 on GC cell function. Flow cytometric detection of apoptosis after RBP4 knockdown. Nude mice xenograft model elucidates the role of RBP4 for GC in vivo. Related proteins of the RAS signaling pathway were analyzed by employing Western blot assays. RBP4 is highly expressed in GC. RBP4 is closely associated with patient survival and sensitivity to a wide range of antitumor agents. Knockdown of RBP4 promoted apoptosis and inhibited cell proliferation, invasion and migration. RBP4 promotes GC tumorigenesis in vivo. Finally, RBP4 modulates the RAS/RAF/ERK axis. RBP4 may promote gastric carcinogenesis and development through the RAS/RAF/ERK axis and is expected to be a novel target for GC treatment.

Integrating trans-omics, cellular experiments and clinical validation to identify ILF2 as a diagnostic serum biomarker and therapeutic target in gastric cancer.

Gastric cancer (GC) lacks serum biomarkers with clinical diagnostic value. Multi-omics analysis is an important approach to discovering cancer biomarkers. This study aimed to identify and validate serum biomarkers for GC diagnosis by cross-analysis of proteomics and transcriptomics datasets. A cross-omics analysis was performed to identify overlapping differentially expressed genes (DEGs) between our previous aptamer-based GC serum proteomics dataset and the GC tissue RNA-Seq dataset in The Cancer Genome Atlas (TCGA) database, followed by lasso regression and random forest analysis to select key overlapping DEGs as candidate biomarkers for GC. The mRNA levels and diagnostic performance of these candidate biomarkers were analyzed in the original and independent GC datasets to select valuable candidate biomarkers. The valuable candidate biomarkers were subjected to bioinformatics analysis to select those closely associated with the biological behaviors of GC as potential biomarkers. The clinical diagnostic value of the potential biomarkers was validated using serum samples, and their expression levels and functions in GC cells were validated using in vitro cell experiments. Four candidate biomarkers (ILF2, PGM2L1, CHD7, and JCHAIN) were selected. Their mRNA levels differed significantly between tumor and normal tissues and showed different diagnostic performances for GC, with areas under the receiver operating characteristic curve (AUROCs) of 0.629-0.950 in the TCGA dataset and 0.736-0.840 in the Gene Expression Omnibus (GEO) dataset. In the bioinformatics analysis, only ILF2 (interleukin enhancer-binding factor 2) gene levels were associated with immune cell infiltration, some checkpoint gene expression, chemotherapy sensitivity, and immunotherapy response. Serum levels of ILF2 were higher in GC patients than in controls, with an AUROC of 0.944 for the diagnosis of GC, and it was also detected in the supernatants of GC cells. Knockdown of ILF2 by siRNA significantly reduced the proliferation and colony formation of GC cells. Overexpression of ILF2 significantly promotes the proliferation and colony formation of gastric cancer cells. Trans-omics analysis of proteomics and transcriptomics is an efficient approach for discovering serum biomarkers, and ILF2 is a potential diagnostic biomarker and therapeutic target of gastric cancer.

CircTMEM87A promotes the tumorigenesis of gastric cancer by regulating the miR-1276/SLC7A11 axis.

Gastric cancer (GC) is a common malignancy with high incidence and mortality, and its pathogenesis involves the regulation of circular RNAs (circRNAs). However, the molecular mechanism of circTMEM87A in GC malignant progression is uncertain. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the expressions of circTMEM87A, miR-1276, and solute carrier family 7 membrane 11 (SLC7A11). Western blot was applied to detect protein expression levels of EMT-related proteins (vimentin and E-cadherin) and SLC7A11. Cell counting kit-8 assay (CCK8) and thymidine analog 5-ethynyl-2'-deoxyuridine (EdU) were performed to assess cell proliferation. Apoptosis was investigated using flow cytometry. Transwell assay and wound healing assay were carried out to examine the migration of MKN-7 and AGS cells. The Cellular ROS Assay Kit, Iron Assay Kit, and GSH/GSSG Ratio Detection Assay Kit were utilized to monitor lipid ROS level, iron level, and GSH/GSSG ratio, respectively. The interaction between miR-1276 and circTMEM87A or SLC7A11 was investigated using dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. A xenograft mouse model was constructed to explore the function of circTMEM87A in tumor formation in vivo. CircTMEM87A and SLC7A11 were upregulated, while miR-1276 was downregulated in GC tissues and cells. Knockdown of circTMEM87A suppressed the proliferation and migration and promoted apoptosis and ferroptosis of GC cells. CircTMEM87A served as a sponge for miR-1276, and miR-1276 inhibitor relieved the circTMEM87A knockdown-induced effects on GC cell phenotypes. Similarly, SLC7A11, a downstream gene of miR-1276, rescued miR-1276 overexpression-induced effects on GC cell function. Furthermore, circTMEM87A knockdown inhibited GC cell tumor phenotypes in vivo. CircTMEM87A promoted the proliferation and migration and inhibited apoptosis and ferroptosis of GC cells by increasing SLC7A11 expression through binding to miR-1276.

Exosomal circKIAA1797 Regulates Cell Progression and Glycolysis by Targeting miR-4429/PBX3 Pathway in Gastric Cancer.

In recent years, circular RNAs (circRNAs) are extensively studied in the progression of various types of cancer, while the mechanism of circKIAA1797 is rarely studied in gastric cancer (GC). Hence, this research aimed to investigate the expression of exosomal circKIAA1797 and its biological function in GC cells. Exosomes were extracted from the serum of GC patients and identified by transmission electron microscopy (TEM) and nanoparticle tracking analyzer (NTA). CD81, CD63, Bcl-2, Bax, and pre-leukemia transcription factor 3 (PBX3) protein levels were detected using western blot assay. circKIAA1797, microRNA-4429 (miR-4429), and PBX3 mRNA were determined by quantitative real-time PCR (RT-qPCR). Cell proliferation, migration, invasion, and apoptosis were assessed using colony formation assay, 5-Ethynyl-2'-deoxyuridine (EdU) assay, transwell assay, and flow cytometry assay. Glucose consumption and lactate production levels were examined using glycolysis detection kits. The interaction between miR-4429 and circKIAA1797 or PBX3 was identified using dual-luciferase reporter assay, RNA pull-down assay, and RNA immunoprecipitation (RIP) assay. Xenograft mouse model assay was used to investigate the effect of exosomal circKIAA1797 in vivo. It was found that circKIAA1797 was up-regulated in GC tissues and cells, as well as in the exosomes derived from the serum of GC patients. Silencing of exosomal circKIAA1797 could hamper cell progression and glycolytic metabolism of GC. Mechanically, circKIAA1797 acted as a sponge of miR-4429 to regulate PBX3 expression. Moreover, the knockdown of exosomal circKIAA1797 repressed tumor growth in vivo. Our data demonstrated that knockdown of exosomal circKIAA1797 suppressed GC malignant phenotypes by regulating miR-4429/PBX3 axis, which might offer a promising therapeutic strategy for GC treatment.

RNF6 promotes gastric cancer progression by regulating CCNA1/CREBBP transcription

ABSTRACT Ring finger protein 6 (RNF6) is a member of the E3 ubiquitin ligase family. Previous studies have reported the involvement of RNF6 as a ubiquitin ligase in the progression of gastric cancer (GC). However, this study found that RNF6 has a clear localization in the nucleus of GC, indicating a role other than ubiquitin ligase. Further chromatin immunoprecipitation sequencing (ChIP-seq) analysis revealed that RNF6 has DNA binding and transcriptional regulatory effects and is involved in important pathways such as tumor cell cycle and apoptosis. Cyclin A1 (CCNA1) and CREB binding protein (CREBBP) are downstream targets for RNF6 transcription regulation in GC. RNF6 binds to the promoter region of CCNA1/CREBBP and is actively regulating their expression in GC cells. Silencing CCNA1/CREBBP partially reversed the promoting effect of RNF6 overexpression on the biological function of GC cells. Our study suggests that RNF6 promotes the progression of GC by regulating CCNA1/CREBBP transcription.

VEPH1 suppresses the progression of gastric cancer by regulating the Hippo-YAP signalling pathway

BackgroundVentricular zone-expressed PH domain-containing protein homologue 1 (VEPH1) is a recently discovered intracellular adaptor protein that plays an important role in human development. It has been reported that VEPH1 is closely related to the process of cellular malignancy, but its role in gastric cancer has not been elucidated. This study investigated the expression and function of VEPH1 in human gastric cancer (GC). MethodsWe performed qRT‒PCR, Western blotting, and immunostaining assays in GC tissue samples to evaluate VEPH1 expression. Functional experiments were used to measure the malignancy of GC cells. A subcutaneous tumorigenesis model and peritoneal graft tumour model were established in BALB/c mice to determine tumour growth and metastasis in vivo. ResultsVEPH1 expression is decreased in GC and correlates with the overall survival rates of GC patients. VEPH1 inhibits GC cell proliferation, migration, and invasion in vitro and suppresses tumour growth and metastasis in vivo. VEPH1 regulates the function of GC cells by inhibiting the Hippo-YAP signalling pathway, and YAP/TAZ inhibitor-1 treatment reverses the VEPH1 knockdown-mediated increase in the proliferation, migration and invasion of GC cells in vitro. Loss of VEPH1 is associated with increased YAP activity and accelerated epithelial-mesenchymal transition (EMT) in GC. ConclusionVEPH1 inhibited GC cell proliferation, migration, and invasion in vitro and in vivo and exerted its antitumour effects by inhibiting the Hippo-YAP signalling pathway and EMT process in GC.

Overexpression of miR-431-5p impairs mitochondrial function and induces apoptosis in gastric cancer cells via the Bax/Bcl-2/caspase3 pathway

To investigate the expression of microRNA miR-431-5p in gastric cancer (GC) tissues and its effects on apoptosis and mitochondrial function in GC cells. The expression level of miR-431-5p in 50 clinical samples of GC tissues and paired adjacent tissues was detected using real-time fluorescence quantitative PCR, and its correlation with the clinicopathological features of the patients was analyzed. A cultured human GC cell line (MKN-45 cells) were transfected with a miR-431-5p mimic or a negative control sequence, and the cell proliferation, apoptosis, mitochondrial number, mitochondrial potential, mitochondrial permeability transition pore (mPTP), reactive oxygen species (ROS) production and adenosine triphosphate (ATP) content were detected using CCK-8 assay, flow cytometry, fluorescent probe label, or ATP detection kit. The changes in the expression levels of the apoptotic proteins in the cells were detected with Western blotting. The expression level of miR-431-5p was significantly lower in GC tissues than in the adjacent tissues (P < 0.001) and was significantly correlated with tumor differentiation (P=0.0227), T stage (P=0.0184), N stage (P=0.0005), TNM stage (P=0.0414) and vascular invasion (P=0.0107). In MKN-45 cells, overexpression of miR-431-5p obviously inhibited cell proliferation and induced cell apoptosis, causing also mitochondrial function impairment as shown by reduced mitochondrial number, lowered mitochondrial potential, increased mPTP opening, increased ROS production and reduced ATP content. Overexpression of miR-431-5p significantly downregulated the expression of Bcl-2 and increased the expressions of pro-apoptotic proteins p53, Bcl-2 and cleaved caspase-3 protein. The expression of miR-431-5p is down-regulated in GC, which results in mitochondrial function impairment and promotes cell apoptosis by activating the Bax/Bcl-2/caspase3 signaling pathway, suggesting the potential role of miR-431-5p in targeted therapy for GC.

PGAM5 promotes tumorigenesis of gastric cancer cells through PI3K/AKT pathway

PGAM5 has been associated with the development of tumours, however, its function in gastric cancer (GC) remains unexplored. Here, we investigated the role and mechanism of PGAM5 in regulating GC. The results revealed that PGAM5 was upregulated in GC tissues and cell lines, which was correlated with tumour size and TNM stage. Moreover, PGAM5 knockdown inhibited proliferation, migration, and invasion progression, whereas PGAM5 overexpression promoted the function of GC cells in vitro. PGAM5 also promoted the activation of the PI3K/AKT signalling pathway. Furthermore, MK-2206, an AKT inhibitor, reversed the proliferation and activation of the PI3K/AKT signalling pathway induced by PGAM5 knockdown in GC cells. In conclusion, PGAM5 promotes the proliferation of GC by positively regulating the activation of the PI3K/AKT signalling pathway in GC cells.

ZFP36L1 Promotes Gastric Cancer Progression via Regulating JNK and p38 MAPK Signaling Pathways.

The RNA-binding protein Zinc Finger Protein 36 like 1(ZFP36L1) plays an important role in regulating the AU-rich elements (AREs) in the 3' untranslated region (3' UTR) of mRNAs, indicating a potential link between its expression and cancers. However, the role and mechanism of ZFP36L1 in gastric cancer (GC) are unclear. This study aimed to explore the role and mechanism of ZFP36L1 in gastric cancer. GC tissue samples and matched normal gastric tissues were collected, and the ZFP36L1 expression in these samples was evaluated by immunohistochemistry analysis. GC cells with different differentiation were selected for in vitro experiments. The ZFP36L1 expression in GC cells was examined by quantitative real-time polymerase chain reaction (qRTPCR) and Western blot analysis. The viability and invasiveness of GC cells were assayed by 5- Ethynyl-2-deoxyuridine (EdU) and Transwell assays, respectively. Western blot assay was used to detect the expression of epithelial-to-mesenchymal transition (EMT) related proteins and proteins of the c-Jun N-terminal kinase (JNK) and p38 Mitogen-Activated Protein Kinase (MAPK) signaling pathways. ZFP36L1 is overexpressed in GC tissues. Patients with high ZFP36L1 expression have a poor prognosis. Moreover, ZFP36L1 is overexpressed in the cell lines with a high degree of malignancy. ZFP36L1 increases cell proliferation, invasion, and migration in vitro. Furthermore, ZFP36L1 induces EMT. The JNK inhibitor and p38 inhibitor alone or in combination affect the biological function of GC cells. Furthermore, ZFP36L1 promotes GC progression by inhibiting JNK and p38 MAPK signaling pathways. RNA-binding protein ZFP36L1 exerts a role in the occurrence of gastric cancer by the regulation of the JNK and p38 MAPK signaling pathways. The combination of inhibitors of the JNK and p38 MAPK signaling pathways could be a novel treatment strategy for gastric cancer.

The Role of YAP-JNK in the Mitophagy, Migration, and Invasion of Gastric Cancer.

To determine the function of the YAP-JNK-mitophagy signalling pathway in gastric cancer (GC). An observational study. Seventh People's Hospital of Shanghai University of TCM (Traditional Chinese Medicine), between June 2019 and June 2021. Tissues from 30 cases of gastric cancer and corresponding adjacent tissues were collected. RT-qPCR was employed to detect the expression of YAP and JNK in GC samples. MTT, Wound healing and Transwell assays were used to detect changes in GC cell proliferation, migration, and invasion under different stimulation. LC3 immunofluorescence and mitochondrial membrane potential detection were used to analyse the occurrence of mitochondrial autophagy. The expression of YAP and JNK were significantly increased in GC tissues (p=0.024, 0.033). YAP knockdown inhibited GC cell proliferation, migration, and invasion. Further studies showed that YAP affects GC cell function by targeting JNK. In addition, YAP-JNK signalling was found to regulate GC cell proliferation, migration, and invasion mainly through regulating the occurrence of mitophagy. These findings revealed that YAP-JNK promotes the development of GC by targeting mitophagy. Gastric cancer, YAP, JNK, Autophagy.

ZNF655 mediated by LINC01210/miR-124-3p axis promotes the progression of gastric cancer.

Gastric cancer (GC) is a common malignant tumor that usually originates from the epithelium of the gastric mucosa. ZNF655 was a suppressor gene of many cancers. However, the mechanism of ZNF655 in GC remains unknown. Quantitative polymerase chain reaction was used to assess the expression of ZNF655, LINC01210, and miR-124-3p. Western blotting was used to monitor ZNF655 protein expression. MTT, clone formation, transwell, and flow cytometry were all used to investigate the functions of GC cells. The interactions between ZNF655, LINC01210, and miR-124-3p were confirmed using the dual-luciferase reporter gene assay and the RIP assay. ZNF655 was highly expressed in GC cells. ZNF655 knockdown reduced GC cell viability, proliferation, migration, invasion, and induced apoptosis. The level of miR-124-3p was significantly reduced in GC cells. Besides, miR-124-3p targeted ZNF655 and inhibited its expression. MiR-124-3p mimics inhibited GC cell progression, but ZNF655 overexpression reversed these effects. Moreover, LINC01210 was found to be highly expressed in GC cells and to be able to sponge miR-124-3p. Furthermore, inhibiting miR-124-3p or increasing ZNF655 could counteract the effects of LINC01210 knockdown on GC cell development. Finally, ZNF655 promoted GC cell progression and was regulated by the LINC01210/miR-124-3p axis.

Delivery of LINC00589 via mesoporous silica nanoparticles inhibits peritoneal metastasis in gastric cancer

Peritoneal metastasis is one of the common forms of metastasis in gastric cancer (GC). In this study, we identified the expression pattern of LINC00589 in GC patients and investigate the biological function in GC cells. RNA-pulldown assay was performed to explore the underlying molecular mechanism. Further, we utilize polyethyleneimine-modified mesoporous silica nanoparticles (PMSNs) as the nanocarriers for delivery of LINC00589 encoding plasmid and tested its therapeutic potential for GC with peritoneal dissemination. We revealed that LINC00589 was downregulated in GC tissues and suppressed the metastatic ability of GC cells. Mechanistically, LINC00589 exerted tumor suppressive function by promoting hnRNPA1 protein ubiquitination and proteasomal degradation, thus blocking alternative splicing of PKM to PKM2. Furthermore, LINC00589 delivered by PMSNs could suppress the peritoneal metastasis of GC in vivo and in vitro. This work may provide a new treatment option in GC peritoneal metastasis.

Helicobacter pylori CagA Protein Regulating the Biological Characteristics of Gastric Cancer through the miR-155-5p/SMAD2/SP1 axis.

Helicobacter pylori (Hp) is a grade Ι carcinogen of gastric cancer (GC), and its high infection rate seriously affects human health. Cytotoxin-associated gene A (CagA) plays a key role in the carcinogenesis of Hp as one of its main virulence factors. miR-155-5p is abnormally expressed in patients with GC, associated with the occurrence and development of cancer. However, little is known about the association between CagA and miR-155-5p. (1) Background: This study explored the association and mechanism of CagA and miR-155-5p in GC. (2) Methods: The CagA sequence was obtained from the NCBI. After sequence optimization, it was connected to the pcDNA3.1 vector to construct a CagA eukaryotic expression plasmid (pcDNA-CagA). Quantitative real-time polymerase chain reaction (qRT-PCR) was used to investigate the expression of miR-155-5p and CagA in GC cells. The function of CagA on GC cells was detected by CCK8, wound healing, and Transwell assays. Similarly, the function of miR-155-5p was also studied through the above functional experiments after the miR-155-5p overexpression and knockdown models had successfully been constructed. The associations among CagA, miR-155-5p, and SMAD2/SP1 were evaluated using RNA immunoprecipitation (RIP) and rescue experiments. (3) Results: The expression of miR-155-5p was significantly reduced in GC cells, and the expression of miR-155-5p was further reduced after CagA induction. Both overexpressed CagA and knockdown miR-155-5p cell models enhanced malignant transformation, whereas overexpressed miR-155-5p inhibited malignant transformation in vitro. The function of miR-155-5p on GC cells could be influenced by CagA. We also found that the influence of miR-155-5p on SMAD2 and SP1 could be regulated by CagA. (4) Conclusions: CagA potentially regulates the biological function of GC cells through the miR-155-5p/SMAD2/SP1 axis. miR-155-5p could be a therapeutic target for GC related to CagA.

Enhancer of zeste homolog 2 exerts functions in gastric cancer development via modulating microRNA-222-3p methylation and WEE1 expression.

Enhancer of zeste homolog 2 (EZH2) has been studied in gastric cancer (GC), while the role of EZH2 in GC via binding to microRNA (miR)-222-3p remains obscure. This research aims to unravel the regulatory mechanism of EZH2 in GC progression via the modulation of miR-222-3p/WEE1 axis. Initially, EZH2, miR-222-3p, and WEE1 levels in GC cells and tissues were examined. Thereafter, constructs altering EZH2, miR-222-3p, or WEE1 expression were transfected into GC cells to determine the malignant behaviors involved in tumorigenesis of GC cells. Finally, the targeting relations among EZH2, miR-222-3p, and WEE1 were validated. EZH2 and WEE1 were upregulated while miR-222-3p was down-regulated in GC tissues and cells. The decreased EZH2, silenced WEE1, or restored miR-222-3p constrained the malignant behaviors involved in tumorigenesis of GC cells. Deletion of miR-222-3p could reverse the effect of silenced EZH2 on suppressing the biological functions of GC cells. EZH2 could bind to the promoter of miR-222-3p, and there was a targeting relationship between miR-222-3p and WEE1. Our study demonstrates that EZH2 promotes GC development via the modulation of miR-222-3p/WEE1 axis, thus providing promising therapeutic targets for GC therapy.

APY0201 Represses Tumor Growth through Inhibiting Autophagy in Gastric Cancer Cells.

Gastric cancer (GC) is one of the most common cancers globally. There are currently few effective chemotherapeutic drugs available for GC patients. The inhibitors of phosphatidylinositol kinase containing an FYVE finger structure (PIKfyve) have shown significant anticancer effects in several types of cancers, but their effectiveness in GC remains unknown. In this study, we investigate the effect of APY0201, an inhibitor of PIKfyve, on GC tumor growth and its mechanism of action. It was found that APY0201 inhibited GC cell proliferation in in vitro GC cell model, organoid model, and in vivo xenograft tumor model. Through analyzing cell autophagy, we found that APY0201 might block autophagic flux by impairing lysosome degradation function of GC cells, inducing the accumulation of autophagosomes, thus causing the inhibition of GC cell proliferation. We also found that APY0201 induced G1/S phase arrest in GC cells. Importantly, APY0201 was also effective in inducing repression of autophagy and cell cycle arrest in the mouse tumor xenograft. Our results suggest that APY0201 could be a new promising therapeutic option for GC.

Circ_0006089 promotes gastric cancer growth, metastasis, glycolysis, and angiogenesis by regulating miR-361-3p/TGFB1.

Circular RNA (circRNA) participates in a variety of pathophysiological processes, including the development of gastric cancer (GC). However, the role of circ_0006089 in GC progression and its underlying molecular mechanism need to be further revealed. Quantitative real‐time PCR was utilized for detecting circ_0006089, microRNA (miR)‐361‐3p and transforming growth factor‐β1 (TGFB1) expression. The interaction between miR‐361‐3p and circ_0006089 or TGFB1 was confirmed using a dual‐luciferase reporter assay and an RNA immunoprecipitation (RIP) assay. Cell proliferation, metastasis, apoptosis, and angiogenesis were determined using colony formation assay, EdU assay, transwell assay, flow cytometry, and tube formation assay. Cell glycolysis was evaluated by detecting glucose consumption, lactate production, and ATP levels. In addition, western blot (WB) analysis was used to measure protein expression. Xenograft tumor models were used to assess the effect of circ_0006089 knockdown on GC tumorigenesis. circ_0006089 had been found to be upregulated in GC tissues and cells, and it could act as an miR‐361‐3p sponge. circ_0006089 knockdown suppressed GC proliferation, metastasis, glycolysis, angiogenesis, and increased apoptosis, while this effect could be revoked by miR‐361‐3p inhibitor. TGFB1 was targeted by miR‐361‐3p, and its overexpression reversed the effects of miR‐361‐3p on GC cell function. Also, circ_0006089 promoted TGFB1 expression via sponging miR‐361‐3p. Animal experiments showed that silenced circ_0006089 inhibited GC tumorigenesis through the miR‐361‐3p/TGFB1 pathway. Our results revealed that the circ_0006089/miR‐361‐3p/TGFB1 axis contributed to GC progression, confirming that circ_0006089 might be a potential therapeutic target for GC.

Long non-coding RNA DEPDC1-AS1 promotes proliferation and migration of human gastric cancer cells HGC-27 via the human antigen R-F11R pathway.

ObjectiveLong non-coding (lnc) RNAs are critical regulators in carcinogenesis. The novel lncRNA DEPDC1 antisense RNA 1 (DEPDC1-AS1) was recently associated with poor prognosis in triple-negative breast cancer and lung adenocarcinoma. However, its role in regulating the malignant progression of gastric cancer (GC) and its molecular mechanism are unclear. We herein explored the functions of DEPDC1-AS1 in GC progression.MethodsDEPDC1-AS1 expression and prognosis in GC tissues were examined by bioinformatics analysis and quantitative reverse transcription polymerase chain reaction. The DEPDC1-AS1 function in GC cells was explored by the cell counting kit-8 assay, colony formation assay, Transwell assay, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling, 5-ethynyl-2′-deoxyuridine-incorporation, and the xenograft tumor model. The DEPDC1-AS1 and human antigen (Hu)R interaction was determined by RNA pull-down and RNA immunoprecipitation.ResultsDEPDC1-AS1 was overexpressed in GC tissues and cell lines, and associated with a worse prognosis in GC patients. In vitro and in vivo assays showed that DEPDC1-AS1 promoted HGC-27 cell proliferation and migration. Mechanistically, DEPDC1-AS1 served as a scaffold by combining with HuR to target the specific mRNA F11R.ConclusionDEPDC1-AS1 plays a crucial role in GC development and progression and is a potential biomarker for the early detection or prognosis of GC.