Signaling Pathway In Gastric Cancer Cells Research Articles

FOXN2, identified as a novel biomarker in serum, modulates the transforming growth factor-beta signaling pathway through its interaction with partitioning defective 6 homolog alpha, contributing to the pathogenesis of gastric cancer

Background and Objective Dysregulated expression of Forkhead Box N2 (FOXN2) has been detected in various cancer types. However, the underlying mechanisms by which FOXN2 contributes to the onset and progression of gastric cancer (GC) remain largely unexplored. This study aimed to elucidate the potential role of FOXN2 within GC, its downstream molecular mechanisms, and its feasibility as a novel serum biomarker for GC. Methods Tissue samples from GC patients and corresponding non-cancerous tissues were collected. Peripheral blood samples were obtained from GC patients and healthy controls. The expression of FOXN2 was determined using quantitative real-time PCR, western blotting, and immunohistochemistry. The expression of FOXN2 in GC cells was modulated by transfection with small interfering RNA (siRNA) or the pcDNA 3.1 expression vector. Cell proliferation was assessed using the Cell Counting Kit-8 and 5-ethynyl-2’-deoxyuridine incorporation assays. The migratory and invasive capacities of cells were evaluated by Transwell assays, apoptosis rates were measured by flow cytometry, and the expression of proliferative, apoptotic, and epithelial-mesenchymal transition (EMT) markers were assessed by western blot analysis. Results FOXN2 was found to be overexpressed in the serum, tissues, and cells of GC, correlating with distant metastasis and TNM staging. FOXN2 demonstrated diagnostic value in differentiating GC patients from healthy individuals, with higher levels of FOXN2 being indicative of poorer survival rates. Silencing FOXN2 in vitro inhibited the proliferation, invasion, migration, and EMT of GC cells, while promoting apoptosis. FOXN2 was shown to regulate the transforming growth factor-beta (TGFβ) receptor signaling pathway in GC cells via its interaction with Partitioning Defective 6 Homolog Alpha (PARD6A). Conclusion In summary, our data suggest that FOXN2 acts as an oncogenic factor in GC, modulating the TGFβ pathway by binding to PARD6A, thereby influencing gastric carcinogenesis. This study underscores the functional significance of FOXN2 as a potential serum biomarker and therapeutic target in GC.

CLEC4D as a Novel Prognostic Marker Boosts the Proliferation and Migration of Gastric Cancer via the NF-κB/AKT Signaling Pathway.

The functions of C-type lectin domain family 4 member D (CLEC4D), one member of the C-type lectin/C-type lectin-like domain superfamily, in immunity have been well described, but its roles in cancer biology remain largely unknown. This study aims to explore the role of CLEC4D in gastric cancer (GC). Bioinformatics preliminarily analyzed the expression of CLEC4D in gastric cancer. Immunohistochemical staining was used to detect the expression level and clinical pathological characteristics of CLEC4D in gastric cancer. The biological function of CLEC4D in gastric cancer cell lines was verified through in vitro and in vivo experiments. In this study, CLEC4D expression was found to be markedly increased in gastric cancer (GC) tissues compared with matched normal gastric tissues, and high CLEC4D expression independently predicted unfavorable overall survival in patients with GC. Knockdown of CLEC4D markedly inhibited GC cell proliferation and migration. Mechanistically, CLEC4D knockdown deactivated the Akt and NF-κB signaling pathways in GC cells. Together, these results demonstrate that aberrantly increased CLEC4D expression promotes cancer phenotypes via the Akt and NF-κB signaling pathways in GC cells.

Dual PI3K/mTOR inhibitor PF-04979064 regulates tumor growth in gastric cancer and enhances drug sensitivity of gastric cancer cells to 5-FU

Gastric cancer (GC) is characterized by high tumor heterogeneity, increased surgical difficulty, and limited chemotherapy efficacy, and it is associated with a poor prognosis. The abnormal proliferation of cells involves abnormal activation of the PI3K/AKT/mTOR signaling pathway. Inhibition of this signaling pathway can inhibit tumor cell proliferation and induce cell apoptosis. This study evaluated the effect of PF-04979064, a dual inhibitor of PI3K and mTOR, on human GC cells. PF-04979064 significantly inhibited the proliferation of human gastric adenocarcinoma AGS cells and the undifferentiated GC cell line HGC-27, promoting cell apoptosis. Combination treatment with PF-04979064 and the GC first-line clinical drug 5-FU showed synergistic effects, and PF-04979064 markedly increased the sensitivity of GC cells to chemotherapy drugs. Western blot results showed that PF-04979064 significantly inhibited the PI3K/AKT/mTOR signaling pathway in GC cells, whereas RNA seq results demonstrated substantial alterations in gene expression profiles upon treatment with PF-04979064. This study provides insight into the effects of PF-04979064, thereby establishing a solid foundation for its potential clinical application in the treatment of GC.

POU5F1 promotes the proliferation, migration, and invasion of gastric cancer cells by reducing the ubiquitination level of TRAF6

POU5F1 plays an important role in maintaining the cancer stem cell (CSC) -like properties of gastric cancer (GC) cells. The impact of POU5F1 on the proliferation and metastasis of GC was examined, along with the potential of ATRA as a specific therapeutic agent for GC. The dysregulation of POU5F1 expression in GC tissues was analyzed using public databases and bioinformatics techniques, and the disparity in POU5F1 expression between normal gastric tissues and GC tissues was further assessed through western blot, RT-qPCR, and immunohistochemistry. The present study aimed to investigate the impact of POU5F1 on the proliferation, migration, and invasion of GC cells through both in vivo and in vitro experiments. Additionally, the effects of ATRA on the proliferation, migration, and invasion of GC cells were examined using in vivo and in vitro approaches. Our findings revealed a significant upregulation of POU5F1 in GC tissues, which was found to be associated with a poorer prognosis in patients with GC. Moreover, POU5F1 was observed to enhance the proliferation, migration, and invasion of GC cells in vitro, as well as promote subcutaneous tumor growth and lung metastasis of GC cells in vivo. The overexpression of POU5F1 mechanistically triggers the process of Epithelial-mesenchymal transition (EMT) by down-regulating E-Cadherin and up-regulating N-Cadherin and VIM. POU5F1 hinders the ubiquitination of TRAF6 through negative regulation of TRIM59, thereby facilitating the activation of the NF-κB pathway. Furthermore, the administration of ATRA effectively impedes the proliferation, migration, and invasion of GC cells by suppressing the expression of POU5F1. The upregulation of POU5F1 elicits EMT, fosters the initiation of the NF-κB signaling pathway in GC cells, and stimulates the proliferation, invasion, and metastasis of GC cells. All-trans retinoic acid (ATRA) can impede these POU5F1-induced effects, thereby potentially serving as an adjunctive therapeutic approach for GC.

The ASH1L-AS1-ASH1L axis controls NME1-mediated activation of the RAS signaling in gastric cancer.

Gastric cancer (GC) is one of the most leading cause of malignancies. However, the molecular mechanisms underlying stomach carcinogenesis remain incompletely understood. Dysregulated genetic and epigenetic alternations significantly contribute to GC development. Here, we report that ASH1L and its antisense lncRNA ASH1L-AS1, which are transcribed from the most significant GC-risk signal at 1q22, act as novel oncogenes. The high levels of ASH1L or lncRNA ASH1L-AS1 expression in GC specimens are associated with worse prognosis of patients. In line with this, ASH1L and ASH1L-AS1 are functionally important in promoting GC disease progression. LncRNA ASH1L-AS1 up-regulates ASH1L transcription, increases histone methyltransferase ASH1L expression and elevates genome-wide H3K4me3 modification levels in GC cells. Furthermore, ASH1L-AS1 directly interacts with transcription factor NME1 protein to form the ASH1L-AS1-NME1 ribonucleoprotein, which transcriptionally promotes expression of ASH1L, ASH1L-AS1, KRAS and RAF1, and activates the RAS signaling pathway in GC cells. Taken together, our data demonstrated that the ASH1L-AS1-ASH1L regulatory axis controls histone modification reprogram and activation of the RAS signaling in cancers. Thus, ASH1L-AS1 might be a novel targets of GC therapeutics and diagnosis in the clinic.

SMYD3 drives the proliferation in gastric cancer cells via reducing EMP1 expression in an H4K20me3-dependent manner

Protein lysine methyltransferase SET and MYND domain-containing 3 (SMYD3) is aberrantly expressed in various cancer settings. The mechanisms that SMYD3 activates the expression of critical pro-tumoral genes in an H3K4me3-dependent manner have been well described in previous reports. Besides H3K4me3, H4K20me3 is another catalytic product of SMYD3, however it is a transcriptionally repressive hallmark. Since it is not clear that how SMYD3-elicited transcriptionally repressive program functions in cancer, we used gastric cancer (GC) as a model to investigate the roles of SMYD3-H4K20me3. Herein, online bioinformatics tools, quantitative PCR, western blotting and immunohistochemistry assays demonstrated that SMYD3 expression was markedly increased in GC tissues from our institutional and The Cancer Genome Atlas (TCGA) cohort. Additionally, aberrantly increased SMYD3 expression was closely associated with aggressive clinical characteristics and poor prognosis. Depletion of endogenous SMYD3 expression using shRNAs significantly attenuates the proliferation in GC cells and Akt signaling pathway in vitro and in vivo. Mechanistically, chromatin immunoprecipitation (ChIP) assay showed that SMYD3 epigenetically repressed the expression of epithelial membrane protein 1 (EMP1) in an H4K20me3-dependent manner. Gain-of-function and rescue experiments validated that EMP1 inhibited the propagation of GC cells and reduced p-Akt (S473) level. Based on these data, pharmaceutical inhibition of SMYD3 activity using the small inhibitor BCI-121 deactivated Akt signaling pathway in GC cells and further impaired the cellular viability in vitro and in vivo. Together, these results demonstrate that SMYD3 promotes the proliferation in GC cells and may be a valid target for therapeutic intervention of patients with GC.

N6-methyladenosine modification of CENPF mRNA facilitates gastric cancer metastasis via regulating FAK nuclear export.

N6-methyladenosine (m6 A) modification is the most common modification that occurs in eukaryotes. Although substantial effort has been made in the prevention and treatment of gastric cancer (GC) in recent years, the prognosis of GC patients remains unsatisfactory. The regulatory mechanism between m6 A modification and GC development needs to be elucidated. In this study, we examined m6 A modification and the downstream mechanism in GC. Dot blotting assays, The Cancer Genome Atlas analysis, and quantitative real-time PCR (qRT-PCR) were used to measure the m6 A levels in GC tissues. Methylated RNA-immunoprecipitation sequencing and RNA sequencing were performed to identify the targets of m6 A modification. Western blotting, Transwell, wound healing, and angiogenesis assays were conducted to examine the role of centromere protein F (CENPF) in GC in vitro. Xenograft, immunohistochemistry, and in vivo metastasis experiments were conducted to examine the role of CENPF in GC in vivo. Methylated RNA-immunoprecipitation-qPCR, RNA immunoprecipitation-qPCR and RNA pulldown assays were used to verify the m6 A modification sites of CENPF. Gain/loss-of-function and rescue experiments were conducted to determine the relationship between CENPF and the mitogen-activated protein kinase (MAPK) signaling pathway in GC cells. Coimmunoprecipitation, mass spectrometry, qRT-PCR, and immunofluorescence assays were performed to explore the proteins that interact with CENPF and elucidate the regulatory mechanisms between them. CENPF was upregulated in GC and facilitated the metastasis of GC both in vitro and in vivo. Mechanistically, increased m6 A modification of CENPF was mediated by methyltransferase 3, and this modified molecule could be recognized by heterogeneous nuclear ribonucleoprotein A2/B1 (HNRNPA2B1), thereby promoting its mRNA stability. In addition, the metastatic phenotype of CENPF was dependent on the MAPK signaling pathway. Furthermore, CENPF could bind to FAK and promote its localization in the cytoplasm. Moreover, we discovered that high expression of CENPF was related to lymphatic invasion and overall survival in GC patients. Our findings revealed that increased m6 A modification of CENPF facilitates the metastasis and angiogenesis of GC through the CENPF/FAK/MAPK and epithelial-mesenchymal transition axis. CENPF expression was correlated with the clinical features of GC patients; therefore, CENPF may serve as a prognostic marker of GC.

LncRNA DLEU2 silencing impedes the migration, invasion and EMT in gastric cancer cell by suppressing PI3K/AKT signaling pathway

Context: The high expression of long non-coding RNA deleted in lymphocytic leukaemia 2 (lncRNA DLEU2) has been confirmed in gastric cancer (GC). Objective: However, the detailed mechanism concerning its involvement in GC remained unclear, which we aimed to explore in this study. Materials and methods: LncRNA DLEU2 expression in GC was estimated by bioinformatic analysis, and the relationship between the expression of DLEU2 and the clinicopathological characteristics of patients with GC was performed. qRT-PCR was employed to detect the expression of lncRNA DLEU2 and confirm the transfection efficiency following the knockdown or overexpression of DLEU2. Functional assays, including CCK-8, flow cytometry, scratching test and Transwell assays, were used to determine the role of DLEU2 in tumor phenotypes. The effects of DLEU2 on the PI3K/Akt pathway were detected by western blot. For elucidating the functions of DLEU2/PI3K/Akt axis in GC, we inhibited the PI3K/Akt pathway in rescue experiments, and evaluated the expression levels of epithelial-mesenchymal transition (EMT)-related proteins by western blot. Results: The expression of DLEU2 was aberrantly up-regulated in GC tissues and cells, which was correlated with the degree of tumor differentiation, cancer antigen 19-9 (CA19-9) and Lauren histologic classification of patients with GC. Silencing of DLEU2 induced apoptosis, attenuated viability, migration and invasion as well as inhibited the PI3K/Akt signaling pathway in GC cells. Mechanistically, the DLEU2/PI3K/Akt axis promoted the progression of GC and the EMT by down-regulating the expression of E-Cadherin and up-regulating those of N-Cadherin and Vimentin. Discussion and conclusions: LncRNA DLEU2 promoted the migration, invasion and EMT in GC by activating the PI3K/Akt pathway.

Curcumin inhibits the cancer‑associated fibroblast‑derived chemoresistance of gastric cancer through the suppression of the JAK/STAT3 signaling pathway.

The present study aimed to investigate whether the Janus-activated kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) signaling pathway is a critical mechanism underlying the cancer-associated fibroblast (CAF)-induced chemoresistance of gastric cancer (GC). In addition, the present study tried to suggest a natural product to compromise the effects of CAF on the chemoresistance of GC. The results of cell proliferation assay revealed that the conditioned medium (CM) collected from CAFs further increased resistance to 5-fluorouracil (5-FU) in GC cell lines. Secretome analysis revealed that the levels of several secreted proteins, including C-C motif chemokine ligand 2, C-X-C motif chemokine ligand 1, interleukin (IL)-6 and IL-8, were increased in the CM from CAFs co-cultured with cancer cells compared to CM from cancer cells. Western blot analysis revealed that CAFs activated the JAK/STAT3 signaling pathway in cancer cells. The experimental models revealed that curcumin abrogated the CAF-mediated activation of the JAK/STAT3 signaling pathway in GC cells. In vivo data revealed the synergistic effects of curcumin with 5-FU treatment in xenograft GC tumors. These data strongly suggest that the suppression of the JAK/STAT3 signaling pathway counteracts the CAF-induced chemoresistance of GC cells. It is suggested that curcumin may be a suitable natural product which may be used to overcome chemoresistance by inhibiting the CAF-induced activation of the JAK/STAT3 signaling pathway in GC.

Exploring the Mechanism of Weikang Keli in Inhibiting Gastric Cancer through the MAPK Signaling Pathway: Based on Network Pharmacology and Experimental Verification.

Background With a high incidence and limited treatments, gastric cancer (GC) seriously threatens human health worldwide. Weikang Keli (WK) is a compound prescription summed up from clinical experience. In our previous studies, WK has been proved to exert antitumor effects. However, there are no research studies to discuss and verify its mechanism as a compound. Objective The aim of the study is to explore the potential molecular mechanism of WK in the treatment of GC with the aid of network pharmacology and verify it through experiments. Methods Related databases were used to obtain genes and targets of WK and gastric cancer. A protein-protein interaction (PPI) network is constructed and visualized by Cytoscape 3.7.2. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were used to analyze core targets. The cell viability of MFC and BGC-823 cells was determined by CCK8. Immunofluorescence was used to determine autophagy of GC cells. Moreover, the effect of WK on the MAPK signaling pathway in GC cells and tumor tissues of ICR mice was detected by Western blot. Results A total of 106 cross targets of WK and GC were obtained. According to the enrichment analysis of GO and KEGG, we target the MAPK signaling pathway to discuss the mechanism of WK on GC. Cell experiments proved that WK inhibited the viability of gastric cancer cells in a dose-dependent and time-dependent manner. Autophagosome aggregation and an increase in the expression of an autophagy marker protein LC3-II can also be observed in WK groups. Further animal experiments showed that the tumor inhibition rate of WK showed a dose-effect relationship. Moreover, the expressions of p-JNK, p-p38, and p-ERR1/2 proteins in the MAPK signaling pathway in WK Group were downregulated both in the cell and animal experiments, compared with the blank control group. Conclusion WK showed an explicit antitumor effect on gastric cancer through the MAPK signaling pathway, and the curative effect varies in different concentrations. Besides, in model mice, the antitumor effect of high-dose WK group is close to that of platinum. This study provided a theoretical basis for the application of WK in the clinical treatment of gastric cancer.

Oxysterol binding protein-like 3 (OSBPL3) is a novel driver gene that promotes tumor growth in part through R-Ras/Akt signaling in gastric cancer

Gastric cancer (GC) is one of the most lethal malignant tumors. To improve the prognosis of GC, the identification of novel driver genes as therapeutic targets is in urgent need. Here, we aimed to identify novel driver genes and clarify their roles in gastric cancer. OSBPL3 was identified as a candidate driver gene by in silico analysis of public genomic datasets. OSBPL3 expression was analyzed by RT-qPCR and immunohistochemistry in GC cells and tissues. The biological functions and mechanisms of OSBPL3 in GC were examined in vitro and in vivo using GC cells. The association between OSBPL3 expression and clinical outcome in GC patients was also evaluated. Overexpression of OSBPL3 was detected in GC cells with OSBPL3 DNA copy number gains and promoter hypomethylation. OSBPL3-knockdown reduced GC cell growth in vitro and in vivo by inhibiting cell cycle progression. Moreover, an active Ras pull-down assay and western blotting demonstrated that OSBPL3 activates the R-Ras/Akt signaling pathway in GC cells. In a clinical analysis of two GC datasets, high OSBPL3 expression was predictive of a poor prognosis. Our findings suggest that OSBPL3 is a novel driver gene stimulating the R-Ras/Akt signaling pathway and a potential therapeutic target in GC patients.

FOXC1 Negatively Regulates DKK1 Expression to Promote Gastric Cancer Cell Proliferation Through Activation of Wnt Signaling Pathway.

Gastric cancer (GC), characterized by uncontrolled growth, is a common malignant tumor of the digestive system. The Wnt signaling pathway plays an important role in the tumorigenesis and proliferation of GC. Many studies on this signaling pathway have focused on its intracellular regulatory mechanism, whereas little attention has been given to extracellular regulatory factors. Dickkopf-1 (Dkk1) is a secretory glycoprotein, and it can bind inhibit activation of the Wnt pathway. However, the regulation and mechanism of DKK1 in the proliferation of GC remain unclear. FOXC1 plays an important role in organ development and tumor growth, but its role in GC tumor growth remains unknown. In this study, we found that the FOXC1 is highly expressed in patients with GC and high expression of FOXC1 correlates to poor prognosis. In addition, we found that the Wnt signaling pathway in GC cells with high FOXC1 expression was strongly activated. FOXC1 negatively regulates DKK1 expression by binding to its promoter region, thereby promoting the activation of Wnt pathway. FOXC1 can also form a complex with unphosphorylated β-catenin protein in the cytoplasm and then dissociates from β-catenin in the nucleus, thereby promoting the entry of β-catenin into the nucleus and regulating expression of c-MYC, which promotes the proliferation of GC cells. Our study not only reveals the function and mechanism of FOXC1 in GC, but also provides a potential target for clinic GC treatment.

Glaucocalyxin a prevents hypoxia-induced epithelial-mesenchymal transition in human gastric cancer cells through the PI3K/Akt signaling pathway

Hypoxia is a frequent occurrence in most solid tumors and associated with multiple cancer progression. Glaucocalyxin A (GLA) has been found to exhibit anti-tumor effect in several types of cancer, except gastric cancer (GC). The present study aimed to evaluate the function of GLA in GC and explore the underlying mechanism under hypoxia condition. Our results showed that GLA suppressed cell viability of MGC-803 cells in both normoxic or hypoxic conditions. MGC-803 cells were more sensitive to GLA in hypoxic condition. GLA attenuated hypoxia-induced migration and invasion of GC cells. Western blot assay proved that GLA elevated E-cadherin expression, as well reduced N-cadherin and vimentin expressions in hypoxia-induced GC cells. Moreover, we also found that GLA suppressed the expression of HIF-1α in both mRNA and protein levels. Furthermore, GLA blocked hypoxia-induced activation of PI3K/Akt pathway in GC cells. Notably, insulin like growth factor 1 (IGF-1), an activator of PI3K/Akt pathway, reversed the effects of GLA on cell migration, invasion and EMT in hypoxia-treated MGC-803 cells. In conclusion, these findings demonstrated that GLA exerted inhibitory effects on cell migration, invasion and epithelial to mesenchymal transition (EMT) via the PI3K/Akt signaling pathway in GC cells.

MicroRNA-582 Potentiates Liver and Lung Metastasis of Gastric Carcinoma Cells Through the FOXO3-Mediated PI3K/Akt/Snail Pathway.

BackgroundThe dysregulation of microRNA (miRNAs) is broadly participated in cancer progression, resulting in sustained cell proliferation by directly targeting various targets. This study investigated the expression of miR-582 in GC and its association with liver metastasis.MethodsFirstly, differentially expressed miRNAs in gastric cancer (GC) tissues were predicted by microarray. Then, the relationship between miR-582 and clinical characteristics of GC patients was analyzed. By silencing of miR-582 in GC cells, the change in malignant biological behaviors of GC cells was detected. The upstream lncRNA, downstream targeting genes of miR-582 and the corresponding signaling pathway were predicted by online databases and verified by luciferase reporter assays, RT-qPCR and Western blot analysis. Finally, the effects of miR-582 on the growth and metastasis of GC cells were detected by in vivo tumorigenesis and metastasis tests.ResultsMiR-582 was highly expressed in GC tissues and related to the metastasis of patients with GC. Silencing of miR-582 expression blocked malignant biological behaviors of GC cells in vitro and in vivo. MiR-582 inhibited forkhead box protein O3 (FOXO3) to upregulate the PI3K/AKT/Snail signaling pathway in GC cells. Besides, GATA6-AS1 was found as an upstream lncRNA to modulate the expression of miR-582.ConclusionMiR-582 induced by GATA6-AS1 silencing promotes the growth and metastasis of GC cells by targeting FOXO3 to induce the activation of the PI3K/AKT/Snail signaling pathway. MiR-582 could be a potential molecular therapy target for patients with GC.

KIF2A promotes the progression via AKT signaling pathway and is upregulated by transcription factor ETV4 in human gastric cancer

Kinesin family protein 2A (KIF2A), an M-type nonmotile microtubule depolymerase, plays essential roles in development and progression of various human cancers. However, its exact function and the underlying mechanism in tumorigenesis of gastric cancer (GC) haven’t been fully elucidated. In the present study, KIF2A was overexpressed in human GC and predicted poor prognosis according to the results of GEPIA analysis. KIF2A was also observed to be upregulated in 82 GC samples compared with paired pericarcinoma tissues. Its overexpression was associated with tumor metastasis (P = 0.047) and Ⅲ stage GC (P = 0.0267). The mRNA and protein expression levels of KIF2A were significantly suppressed in KIF2A specific siRNA transfected GC cells compared with the wild-type and negative control (NC) siRNA transfected cells. Furthermore, the effects of KIF2A on the growth, migration, invasion, and apoptosis of GC cell were evaluated in vitro and the underlying mechanisms were explored. It was found that silencing KIF2A effectively induced the apoptosis, and inhibited the proliferation, migration and invasion capacities of GC cells. Western blot analysis demonstrated that silencing of KIF2A significantly decreased the expression levels of AKT, Cyclin D1 and S6K. Moreover, bioinformatics analysis showed that the promoter (from -414 to -407bp) of KIF2A has the ability to bind to transcription factor ETV4, which was confirmed by bi-luciferase reporter assay using 293T cells. The level of ETV4 was upregulated and positively correlated with KIF2A in human GC tissues. Our results also proved that ETV4 upregulated the expression of KIF2A and blocked the decline of proliferation induced by KIF2A knockdown in MKN-45 and AGS cells. In summary, KIF2A is upregulated by transcription factor ETV4, and its knockdown can effectively inhibit the proliferation and induce the apoptosis of GC cells through the AKT signaling pathway in GC cells, implying that the inhibition of KIF2A expression is a potential target for GC therapy.

The miR-370/UQCRC2 axis facilitates tumorigenesis by regulating epithelial-mesenchymal transition in Gastric Cancer.

Ubiquinol-cytochrome c reductase core protein 2 (UQCRC2) is an important mitochondrial complex III subunit. This study investigated the role of UQCRC2 in gastric cancer (GC) and its upstream regulatory microRNAs (miRNAs). UQCRC2 expression levels were lower in GC tissues than non-carcinoma tissues. Furthermore, UQCRC2 levels were negatively correlated with lymph node metastasis, relapse, and tumor grade. Bioinformatics analysis predicted UQCRC2 as the target gene for miR-370, and this was verified in luciferase reporter assays. MiR-370 levels were inversely correlated with UQCRC2 levels in GC. UQCRC2 overexpression suppressed GC cell migration and invasion in vitro and in vivo, whereas up-regulating miR-370 reversed these effects. Western blotting analysis showed that miR-370 targeted UQCRC2 and positively regulated the epithelial-mesenchymal transition (EMT) signaling pathway in GC cells. Therefore, the miR-370/UQCRC2 axis may regulate EMT signaling pathways to affect tumor proliferation and metastasis and is, thus, a potential target for GC treatment.

CYP2E1 changes the biological function of gastric cancer cells via the PI3K/Akt/mTOR signaling pathway.

The present study investigated the role of cytochrome P450 family 2 subfamily E polypeptide 1 (CYP2E1) in the development and progression of gastric cancer (GC). The expression levels of CYP2E1 in MGC-803 GC cells and normal GES-1 cells were investigated via western blotting, and it was identified that the expression of CYP2E1 was different between GES-1 and MGC-803 cells. CYP2E1 was overexpressed in MGC-803 cells using a lentiviral vector GV358. Cell Counting Kit-8, flow cytometry, cell migration and Matrigel invasion assays suggested that overexpression of CYP2E1 promoted the proliferation and invasion, and inhibited the apoptosis of GC cells. The relationship between CYP2E1 expression and key signaling molecules in the PI3K/Akt/mTOR signaling pathway was assessed. Reverse transcription-quantitative PCR analysis showed that mTOR mRNA expression was significantly increased after overexpression of CYP2E1 (P<0.05). Western blotting results showed that overexpression of CYP2E1 upregulated the expression of phosphorylated (p)-Akt, p-mTOR and p-p70 ribosomal protein S6 kinase (P70S6K; Ser371) proteins (P<0.05). To further investigate the relationship between CYP2E1 and the PI3K/Akt/mTOR signaling pathway in GC cells, MGC-803 cells were treated with the PI3K inhibitor LY294002, and changes in the expression levels of PI3K, AKT, mTOR, P70S6K and CYP2E1 were observed. The present results showed that LY294002 downregulated the expression of PI3K, CYP2E1, AKT, mTOR and P70S6K (P<0.05). Therefore, changes in the biological function of GC cells induced by CYP2E1 overexpression may be via the PI3K/Akt/mTOR signaling pathway.

BP‑1‑102 exerts an antitumor effect on the AGS human gastric cancer cell line through modulating the STAT3 and MAPK signaling pathways.

BP-1-102, a novel inhibitor of signal transducer and activator of transcription 3 (STAT3), exhibits significant antitumor effects in several malignancies in vitro and in vivo. However, its role in gastric cancer (GC) remains to be elucidated. In the present study, the effect and potential molecular mechanisms of BP-102 in human GC cell lines were investigated. The results showed that BP-1-02 dose-dependently inhibited the proliferation of AGS cells, whereas it had little effect on HGC-27 cells. Flow cytometric analysis indicated that BP-1-102 induced apoptosis, but had minimal effect on cell cycle distribution. In addition, cells treated with BP-1-102 demonstrated markedly suppressed migration and invasion capacities. Western blot analysis revealed that BP-1-102 inhibited the phosphorylation of STAT3 and its target genes, including c-Myc, cyclin D1 and survivin, in a time- and dose-dependent manner. Furthermore, it was found that BP-1-102 induced the phosphorylation of c-Jun N-terminal kinase and p38 mitogen-activated protein kinase (MAPK) and inhibited the activation of extracellular signal-related kinases. Taken together, these results demonstrated that BP-1-102 may be a potent antitumor agent that acts through modulating the STAT3 and MAPK signaling pathways in GC cells.

Alpha-enolase promotes gastric cancer cell proliferation and metastasis via regulating AKT signaling pathway

Increased aerobic glycolysis is considered as a hallmark of cancer and targeting key glycolytic enzymes will be a promising therapeutic approach in cancer treatment. Alpha-enolase (ENO1), as a prominent glycolytic enzyme, is upregulated in multiple cancers and its overexpression is involved in tumor cell proliferation and metastasis. In the present study, we aimed to investigate the potential role of ENO1 in the development and progression of gastric cancer (GC). Here, we found that ENO1 expression was upregulated in human GC and was associated with Lauren type, lymph node metastasis (LNM) and TNM stage. Knockdown of ENO1 attenuated GC cell proliferation and metastasis and reversed epithelial-mesenchymal transition (EMT) progress in vitro while ENO1 overexpression did the opposite. ENO1 could modulate AKT signaling pathway in GC cells and the enhanced proliferation and migration ability induced by ENO1 overexpression was impaired after incubation with PI3K inhibitor Ly294002 in SGC7901 cells. Our data demonstrated that ENO1 enhances GC cell proliferation and metastasis through the protein kinase B (AKT) signaling pathway, indicating that ENO1/AKT signaling axis may serve as a potential target for treatment of GC.

IL-21R functions as an oncogenic factor and is regulated by the lncRNA MALAT1/miR-125a-3p axis in gastric cancer.

Interleukin-21 receptor (IL-21R) is involved in the immunological regulation of immune cells and tumor progression in multiple malignancies. However, the potential molecular mechanisms through which non-coding RNAs (ncRNAs) modulate IL-21R signaling in gastric cancer (GC) remain elusive. In this study, the expression of IL-21R was detected by RT-qPCR and western blot analysis in GC cell lines. The association between IL-21R expression and clinicopathological characteristics and the prognosis of patients with GC was analyzed by immunohistochemistry and Kaplan-Meier plotter analysis. The biological functions of IL-21R were analyzed by a series of in vitro and in vivo experiments, and its regulation by ncRNAs was predicted by bioinformatics analysis and confirmed by luciferase assays and rescue experiments. As a result, the expression of IL-21R was found to be significantly increased in GC cell lines and tissues as compared with normal tissues, and was associated with tumor size and lymphatic metastasis, acting as an independent prognostic factor of poor survival and recurrence in patients with GC. The knockdown of IL-21R markedly suppressed GC cell proliferation and invasion, and IL-21R expression was further validated to be negatively regulated by miR-125a-3p (miR-125a). The overexpression of IL-21R reversed the tumor suppressive effects of miR-125a in vitro and in vivo. Moreover, lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) acted as a sponge of miR-125a to modulate the IL-21R signaling pathway in GC cells and represented a risk factor for survival and recurrence in patients with GC. Taken together, the findings of this study reveal an oncogenic role for IL-21R in gastric tumorigenesis and verify that its activation is partly due to the dysregulation of the lncRNA MALAT1/miR-125a axis. These findings may provide a potential prognostic marker for patients with GC.