Epithelial-mesenchymal Transition In Gastric Cancer Cells Research Articles

PXMP4 promotes gastric cancer cell epithelial-mesenchymal transition via the PI3K/AKT signaling pathway.

Peroxisomal membrane protein 4 (PXMP4), a member of the peroxisome membrane protein PXMP2/4 family, participates in the progression of several malignant cancers. Nevertheless, the effect of PXMP4 in the development of gastric cancer (GC) is still unknown. As a result, the focus of this investigation was to elucidate the potential mechanisms of PXMP4 in GC. Firstly, bioinformatics analysis results showed higher expression of PXMP4 in GC tissues. Secondly, clinical analysis of 57 patients with GC revealed correlations between PXMP4 expression and differentiation, depth of invasion, as well as TNM stage. Furthermore, individuals with elevated PXMP4 expression in GC exhibited an unfavorable prognosis. In vitro data showed the involvement of knockdown/overexpression of PXMP4 in the proliferation, invasion, and migration of GC cells, and triggering the epithelial-mesenchymal transition (EMT) of GC cells through the activation of the PI3K/AKT signaling pathway. LY294002, a PI3K/AKT inhibitor, inhibited the expression of PI3K/AKT-related proteins but did not affect the expression of PXMP4. These findings indicate that PXMP4 potentially functions as an upstream molecule in the PI3K/AKT pathway, governing the EMT process in GC.

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.

[Overexpression of BZW1 promotes invasion and metastasis of gastric cancer cells by regulating Wnt/β-catenin signaling and promoting epithelial-mesenchymal transition].

To investigate the expression level of basic leucine zipper and W2 domain-containing protein 1 (BZW1) in gastric cancer, its impact on patient prognosis and the underlying mechanisms. TIMER, UALCAN and Kaplan-Meier Plotter databases were used for analyzing BZW1 expression level gastric cancer tissues and its correlation with tumor grade and stage and the patients' prognosis. We further analyzed BZW1 expressions, disease progression, and postoperative 5-year survival in 102 patients undergoing radical surgery for gastric cancer at our hospital between January, 2014 and December, 2016. Gastric cancer MGC803 cells were examined for changes in migration, invasion, and epithelial-mesenchymal transition (EMT) following lentivirus-mediated BZW1 overexpression or knockdown. The protein and mRNA expressions of BZW1 in gastric cancer tissues were 3.30 and 6.54 times of those in adjacent tissues, respectively (P < 0.01). BZW1 expression in gastric cancer tissues were positively correlated with peripheral blood CEA and CA199 levels (P < 0.01). A high BZW1 expression was an independent risk factor for 5-year survival of gastric cancer patients after radical surgery (P < 0.05, HR=2.070, 95%CI: 1.021-4.196). At the cut-off value of 3.61, BZW1 expression had a sensitivity of 75.56% and a specificity of 71.93% for predicting postoperative 5-year mortality (P < 0.01). In MGC803 cells, BZW1 overexpression obviously promoted cell migration and invasion (P < 0.05), enhanced cellular expressions of N-cadherin and vimentin (P < 0.05) and inhibited the expression of E-cadherin (P < 0.05). Enrichment analysis suggested the involvement of BZW1 in the Wnt/β-catenin signaling pathway. Western blotting confirmed that BZW1 overexpression promoted while BZW1 knockdown inhibited the expressions of Wnt3a, β-catenin and C-myc in MGC803 cells (P < 0.05). BZW1 is highly expressed in gastric cancer tissues to affect the patient prognosis possibly by activation the Wnt/β-catenin signaling pathway to promote EMT of gastric cancer cells.

Overexpression of FERM Domain Containing Kindlin 2 (FERMT2) in Fibroblasts Correlates with EMT and Immunosuppression in Gastric Cancer.

The mesenchymal feature, dominated by epithelial mesenchymal transition (EMT) and stromal cell activation, is one of the main reasons for the aggressive nature of tumors, yet it remains poorly understood. In gastric cancer (GC), the fermitin family homolog-2 (FERMT2) is involved in macrophage signaling, promoting migration and invasion. However, the function of FERMT2 in fibroblasts remains unclear. Here, we demonstrated that downregulation of FERMT2 expression can block EMT in GC cells by inhibiting fibroblast activation in vitro. Furthermore, we found that, in addition to the known pathways, fibroblast-derived FERMT2 promotes M2-like macrophage growth and that in human GC samples, there is a strong positive correlation between FERMT2 and CD163 and CD206 levels. Notably, high FERMT2 expression was significantly associated with poor clinical outcomes and was upregulated in patients with advanced disease. Taken together, our results provide evidence that the fibroblast-FERMT2-EMT-M2 macrophage axis plays a critical role in the GC mesenchymal phenotype and may be a promising target for the treatment of advanced GC.

Leaf Extract from European Olive (Olea europaea L.) Post-Transcriptionally Suppresses the Epithelial-Mesenchymal Transition and Sensitizes Gastric Cancer Cells to Chemotherapy.

The overall survival of patients with the advanced and recurrent gastric cancer (GC) remains unfavorable. In particular, this is due to cancer spreading and resistance to chemotherapy associated with the epithelial-mesenchymal transition (EMT) of tumor cells. EMT can be identified by the transcriptome profiling of GC for EMT markers. Indeed, analysis of the TCGA and GTEx databases (n = 408) and a cohort of GC patients (n = 43) revealed that expression of the CDH2 gene was significantly decreased in the tumors vs. non-tumor tissues and correlated with the overall survival of GC patients. Expression of the EMT-promoting transcription factors SNAIL and ZEB1 was significantly increased in GC. These data suggest that targeting the EMT might be an attractive therapeutic approach for patients with GC. Previously, we demonstrated a potent anti-cancer activity of the olive leaf extract (OLE). However, its effect on the EMT regulation in GC remained unknown. Here, we showed that OLE efficiently potentiated the inhibitory effect of the chemotherapeutic agents 5-fluorouracil (5-FU) and cisplatin (Cis) on the EMT and their pro-apoptotic activity, as was demonstrated by changes in the expression of the EMT markers (E- and N-cadherins, vimentin, claudin-1) in GC cells treated with the aforementioned chemotherapeutic agents in the presence of OLE. Thus, culturing GC cells with 5-FU + OLE or Cis + OLE attenuated the invasive properties of cancer cells. Importantly, upregulation of expression of the apoptotic markers (PARP cleaved form) and increase in the number of cells undergoing apoptosis (annexin V-positive) were observed for GC cells treated with a combination of OLE and 5-FU or Cis. Collectively, our data illustrate that OLE efficiently interferes with the EMT in GC cells and potentiates the pro-apoptotic activity of certain chemotherapeutic agents used for GC therapy.

Tumor-Derived Exosomal LINC01480 Upregulates VCAM1 Expression by Acting as a Competitive Endogenous RNA of miR-204-5p to Promote Gastric Cancer Progression.

Exosomes are a type of cell-derived vesicles that range in size from 30 to 100 nm. They are widely present in various organisms and participate in diverse biological processes, playing crucial roles in tumorigenesis and progression. This study aimed to investigate whether LINC01480 in tumor-derived exosomes is involved in the molecular mechanism of gastric cancer by competitively upregulating the VCAM1 expression through binding miR-204-5p. The study analyzed transcriptome data related to gastric cancer from the cancer genome atlas database and constructed a risk-scoring model for epithelial-mesenchymal transition (EMT)-related lncRNAs to identify eight EMT-related lncRNAs associated with prognosis. EMT-related mRNAs positively correlated with LINC01480 were screened in the ExoRBase database. In vitro cell experiments showed that exosomal LINC01480 can promote the proliferation, migration, invasion, and EMT of gastric cancer cells by upregulating VCAM1 expression through competitive binding with miR-204-5p. In vivo experiments on nude mice showed that exosomal LINC01480 promotes the development of gastric cancer. These results suggest that exosomal LINC01480 could be a potential therapeutic target for gastric cancer.

KLF5‑mediated expression of CARD11 promotes the progression of gastric cancer.

Caspase recruitment domain-containing protein 11 (CARD11) has been reported as functioning in multiple types of cancers. In the present study, the role and mechanism of CARD11 in gastric cancer was investigated. First, CARD11 expression in gastric cancer tissues and the association of CARD11 with overall survival were analyzed by the encyclopedia of RNA interactomes database. CARD11 expression in gastric cancer cells was detected by western blotting and reverse transcription-quantitative PCR analyses. After CARD11 silencing, cell proliferation was evaluated by Cell Counting Kit-8 assay, 5-ethynyl-2'-deoxyuridine staining and flow cytometry analysis. Wound healing and Transwell assays were used to measure the capacities of cell migration and invasion. Additionally, the expression levels of epithelial-mesenchymal transition (EMT)-related proteins and mTOR-related proteins were detected by western blot analysis. HumanTFDB predicted the binding of the transcription factor Krüppel-like factor 5 (KLF5) to the CARD11 promoter, which was confirmed by dual luciferase reporter and chromatin immunoprecipitation assays. To explore the regulatory effects between KLF5 and CARD11, KLF5 was overexpressed to perform the rescue experiments in gastric cancer cells with CARD11 silencing. Results revealed that CARD11 was highly expressed in gastric cancer and was associated with poor prognosis. CARD11 interference inhibited the proliferation of gastric cancer cells and induced cell cycle arrest. Additionally, CARD11 silencing suppressed the migration, invasion and EMT of gastric cancer cells, accompanied by upregulated E-cadherin expression and downregulated N-cadherin and vimentin expression. Moreover, the transcription factor KLF5 positively regulated the transcription of CARD11 in gastric cancer. KLF5 overexpression reversed the effects of interference of CARD11 expression in gastric cancer cells to promote their proliferation, migration, invasion and EMT. KLF5 overexpression also led to a reduction in cell cycle arrest. Finally, interference of CARD11 expression suppressed the mTOR pathway, which was activated by KLF5. In conclusion, KLF5-mediated CARD11 promoted the proliferation, migration and invasion of gastric cancer cells.

Function of hsa_circ_0006646 as a competing endogenous RNA to promote progression in gastric cancer by regulating the miR-665-HMGB1 axis.

Mounting evidences indicate that circular RNAs (circRNAs) are a novel class of non-coding RNAs and play vital roles in the tumorigenesis and aggressiveness including gastric cancer (GC). Nevertheless, the precise functions and underlying mechanisms of circRNAs in GC remain largely unknown. The Gene Expression Omnibus (GEO) data set GSE163416 was analyzed to screen the key circRNAs in GC. hsa_circ_0006646 was chosen for further study. GC tissues and matched adjacent normal gastric mucosal epithelial tissues were obtained from the Fourth Hospital of Hebei Medical University. The expressions of hsa_circ_0006646 was detected using quantitative real-time polymerase chain reaction (qRT-PCR). hsa_circ_0006646 was knocked down to identify its effects on GC cells. Bioinformatics algorithms were analyzed to predict the microRNA (miRNAs) potentially sponged by hsa_circ_0006646 and its target genes. Fluorescence in situ hybridization (FISH) was conducted to determine the subcellular location of hsa_circ_0006646 and the predicted miRNA. Then, qRT-PCR, luciferase reporter assay, radioimmunoprecipitation assay, Western blotting, and miRNA rescue experiments were used to confirm the hsa_circ_0006646-related regulatory axis in GC. Cell Counting Kit-8 (CCK-8), colony formation, wound healing, and Transwell experiments were performed to determine the effect of the hsa_circ_0006646-related regulatory axis on GC cells' malignant behaviors in vitro. The xenograft tumor mouse model was established to evaluate the effect of hsa_circ_0006646 in vivo. hsa_circ_0006646 exhibited a high expression in GC tissues as compared to corresponding adjacent normal gastric mucosal epithelial tissues and its high expression was positively correlated with TNM stage, lymph node invasion and poor prognosis (P<0.05). Knockdown of hsa_circ_0006646 suppressed the proliferation, colony formation, migration, and invasion in GC cells (all P<0.05). hsa_circ_0006646 upregulated high mobility group box 1 (HMGB1) by sponging miR-665 in GC cells (P<0.05). The hsa_circ_0006646-miR-665-HMGB1 axis promoted malignant behaviors and epithelial-mesenchymal transition (EMT) in GC cells by activating the Wnt/β-catenin pathway (P<0.05). The existence of hsa_circ_0006646-miR-665-HMGB1 axis was confirmed in GC specimens (P<0.05). Consequently, down-regulated hsa_circ_0006646 inhibited the progression and EMT of GC cells in vivo (P<0.05). For the first time, we demonstrated that hsa_circ_0006646-miR-665-HMGB1 axis exerted its tumor-promoting effects in GC, which suggested that hsa_circ_0006646 could be potentially targeted for GC treatment.

KLF3 Transcription Activates WNT1 and Promotes the Growth and Metastasis of Gastric Cancer via Activation of the WNT/β-Catenin Signaling Pathway

The transcription factor Krüppel-like factor (KLF) 3 is one of the members of the KLF family, which plays an important role in tumor progression. Nevertheless, the role of KLF3 in the growth and metastasis of gastric cancer (GC) still needs to be elucidated. Bioinformatics analysis showed that KLF3 was overexpressed in patients with GC, and the high expression of KLF3 was correlated with poor survival. KLF3 was also overexpressed in GC clinical samples and cell lines. In vitro functional role of KLF3 in GC cells was explored by a gain-of-function and loss-of-function assay. Overexpressed KLF3 promoted the cell proliferation, migration, invasion, and epithelial-mesenchymal transition of GC cells, whereas suppressed KLF3 inhibited these biological behaviors. The clinical samples and bioinformatics analysis showed that WNT1 was also highly expressed in GC tumor tissues and positively correlated with KLF3 expression. The luciferase reporter assay and chromatin immunoprecipitation result confirmed that KLF3 could directly bind to the WNT1 promoter to increase the transcriptional activity of WNT1, thus regulating its expression. Overexpressed KLF3 enhanced the protein expression level of p-GSK3β(Ser9) and β-catenin, the key elements in the WNT/β-catenin signaling pathway. Repression of KLF3 decreased the level of p-GSK3β(Ser9) and β-catenin. Immunofluorescence images showed that KLF3 promoted nuclear β-catenin accumulation. Inhibition of WNT1 attenuated the proliferation, migration, and invasiveness of KLF3-overexpressing GC cells. Moreover, the xenograft mouse model confirmed that KLF3 promotes GC tumor growth and metastasis in vivo. Our results demonstrated that KLF3 activates the WNT/β-catenin signaling pathway via WNT1 to promote GC tumor growth and metastasis, indicating that repression of KLF3 may act as a potential therapeutic target for patients with GC.

HKDC1 upregulation promotes glycolysis and disease progression, and confers chemoresistance onto gastric cancer.

There is increasing evidence that hexokinase is involved in cell proliferation and migration. However, the function of the hexokinase domain containing protein-1 (HKDC1) in gastric cancer (GC) remains unclear. Immunohistochemistry analysis and big data mining were used to evaluate the correlation between HKDC1 expression and clinical features in GC. In addition, the biological function and molecular mechanism of HKDC1 in GC were studied by in vitro and in vivo assays. Our study indicated that HKDC1 expression was upregulated in GC tissues compared with adjacent nontumor tissues. High expression of HKDC1 was associated with worse prognosis. Functional experiments demonstrated that HKDC1 upregulation promoted glycolysis, cell proliferation, and tumorigenesis. In addition, HKDC1 could enhance GC invasion and metastasis by inducing epithelial-mesenchymal transition (EMT). Abrogation of HKDC1 could effectively attenuate its oncogenic and metastatic function. Moreover, HKDC1 promoted GC proliferation and migration in vivo. HKDC1 overexpression conferred chemoresistance to cisplatin, oxaliplatin, and 5-fluorouracil (5-Fu) onto GC cells. Furthermore, nuclear factor kappa-B (NF-κB) inhibitor PS-341 could attenuate tumorigenesis, metastasis, and drug resistance ability induced by HKDC1 overexpression in GC cells. Our results highlight a critical role of HKDC1 in promoting glycolysis, tumorigenesis, and EMT of GC cells via activating the NF-κB pathway. In addition, HKDC1-mediated drug resistance was associated with DNA damage repair, which further activated NF-κB signaling. HKDC1 upregulation may be used as a potential indicator for choosing an effective chemotherapy regimen for GC patients undergoing chemotherapy.

ISLR interacts with MGAT5 to promote the malignant progression of human gastric cancer AGS cells.

Gastric cancer is a common malignant tumor with high morbidity and mortality. The present study aimed to investigate the role of the immunoglobulin superfamily containing leucine-rich repeat (ISLR) gene in gastric cancer and examine whether ISLR could interact with N-acetylglucosaminyltransferase V (MGAT5) to affect the malignant progression of gastric cancer. The expression of ISLR and MGAT5 in human normal gastric epithelial cells and human gastric cancer cells, and the transfection efficiency of ISLR interference plasmids and MGAT5 overexpression plasmids were all detected by reverse transcription-quantitative PCR (RT-qPCR) and western blot. The viability, proliferation, migration and invasion, and epithelial-mesenchymal transition (EMT) of gastric cancer cells after indicated transfection were detected by Cell counting kit-8 (CCK-8) assay, 5-ethynyl-2'-deoxyuridine (EdU) staining, wound healing assay, and transwell assay. The interaction between ISLR and MGAT5 was confirmed by co-immunoprecipitation. The expression of proteins related to migration, invasion, and EMT was detected by immunofluorescence and western blot. As a result, ISLR was highly expressed in gastric cancer and was associated with poor prognosis. Interference with ISLR inhibited the viability, proliferation, migration, invasion, and EMT of gastric cancer cells. ISLR interacted with MGAT5 in gastric cancer cells. MGAT5 overexpression weakened the effects of ISLR knockdown on suppressing the viability, proliferation, migration, invasion, and EMT of gastric cancer cells. ISLR interacted with MGAT5 to promote the malignant progression of gastric cancer.

Zinc Finger Protein 479 Promotes Metastasis and Epithelial-Mesenchymal Transition in Gastric Cancer via MEK/ERK/DNMT1 Signaling Pathway

The carcinogenic function of zinc finger protein 479 (ZNF479) has been found in a few sorts of cancer. However, the part of ZNF479 in gastric cancer remains vague. In this study, the effect of ZNF479 on gastric cancer cell survival, metastasis and epithelial mesenchymal transition (EMT) was investigated using the Cell Counting Kit-8 (CCK-8), flow cytometry, and transwell assays. Immunofluorescence assay and Western blot was carried out to evaluate the levels of cell cycle, EMT, and MEK/ERK/DNMT1 pathway-related proteins. A lung metastasis cancer mice model was constructed to evaluate the function of ZNF479 on tumor metastasis in vivo. We noticed that overexpression of ZNF479 promoted cell growth, cell cycle progression, invasion and EMT of gastric cancer cells, whereas ZNF479 knockdown appeared the inverse comes about. Moreover, downregulation of ZNF479 hindered tumor metastasis in mice. Advanced investigation implied that ZNF479 was engaged in the regulation of gastric cancer progression by affecting the MEK/ERK/DNMT1 pathway for that the MEK-specific inhibitor PD98059 reversed the impact of ZNF479 overexpression on gastric cancer cells and repressed MEK/ERK/DNMT1 signal. In conclusion, ZNF479 promotes gastric cancer cells by activating the MEK/ERK/DNMT1 pathway, ZNF479 may give a new and viable gene target for gastric cancer intercession.

[CircPCSK5 is highly expressed in gastric cancer and promotes cancer cell proliferation, invasion and epithelial-mesenchymal transition].

To investigate the expression of circPCSK5 in gastric cancer (GC) and its role in regulation of the proliferation, invasion and epithelial-mesenchymal transition (EMT) of GC cells. High-throughput sequencing was performed in 3 pairs of GC and adjacent gastric mucosa tissues to obtain the differential expression profile of circRNA. The expression of circPCSK5 was detected in 62 patients undergoing radical surgery for GC using RT-qPCR, and the correlation between circPCSK5 expression level and clinicopathological data of the patients was analyzed. The overall survival and disease-free survival of the patients were assessed with Kaplan-Meier survival analysis, and the independent risk factors affecting the patients' prognosis were analyzed using Cox proportional hazards regression model. The stability and subcellular localization of circPCSK5 were assessed using RNase R and actinomycin D assays, fluorescence in situ hybridization and nucleocytoplasmic separation assay. CCK-8 assay, EdU assay and Transwell assay were employed to examine the changes in proliferation, migration and invasion of GC cells with circPCSK5 knockdown or overexpression; Western blotting and RT-qPCR assays were used to detect the expression levels of EMT markers in the transfected cells. The expression of circPCSK5 was significantly upregulated in GC tissues and cells (P < 0.001, P < 0.01). The expression level of circPCSK5 was positively correlated with tumor size, vascular invasion, lymph node metastasis and AJCC stage of GC (P < 0.05). The overall survival and disease-free survival were significantly lower in GC patients with high circPCSK5 expression than in those with low circPCSK5 expression (P < 0.001). High circPCSK5 expression was an independent risk factor for a poor prognosis of GC patients (P < 0.05). Knockdown of circPCSK5 significantly inhibited the proliferation, migration and invasion of HGC27 cells (P < 0.01), increased the expressions of E-cadherin, and decreased the expression of N-cadherin and vimentin (P < 0.01). CircPCSK5 overexpression promoted the proliferation, migration and invasion of MKN45 cells (P < 0.01), reduced E-cadherin expression and increased N-cadherin and vimentin expressions (P < 0.01). CircPCSK5 is highly expressed in GC and promotes the proliferation, invasion and EMT of GC cells, suggesting its potential as a prognostic biomarker and therapeutic target for GC.

Wilms tumor 1 associated protein promotes epithelial mesenchymal transition of gastric cancer cells by accelerating TGF-β and enhances chemoradiotherapy resistance.

Wilms tumor 1 associated protein (WTAP) is a key RNA n6-methyladenosine (m6A) methylase, which predicts the occurrence of many diseases, such as liver fibrosis formation, coordinating cancer stem cell function, and promoting tumor development. Gastric cancer (GC) is one of the most common malignant tumors worldwide. However, the role of WTAP in GC development and drug resistance remains unclear. Biological methods and data analysis were used to investigate the expression of WTAP in gastric carcinoma tissue. The expression of transforming growth factor-beta (TGF-β) and epithelial mesenchymal transition (EMT) in GC cells were detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot (WB) with WTAP overexpression cell lines and WTAP knockout cell lines. Gradient concentrations of cisplatin (DDP), gradient cyclophosphamide (CTX), or radiation X-rays were added to WTAP overexpression cell lines and WTAP knockdown cell lines to observe the change of cell viability after radiotherapy and chemotherapy treatment. The expression of WTAP in gastric carcinoma tissue significantly increased as determined by bioinformatics analysis, and a high expression of WTAP was closely associated with poor prognosis of gastric cancer patients. Overexpression of WTAP promoted migration and EMT of GC cells and promoted the expression of TGF-β and the stability of mRNA. WTAP knockdown inhibited migration of GC cells and decreased TGF-β expression and stability of mRNA. In addition, WTAP promoted multiple chemotherapy resistance and radiotherapy resistance in GC. WTAP is a potential predictive biomarker for GC. Our findings revealed a novel mechanism by which WTAP regulates chemoradiotherapy resistance, extending the understanding of the m6A machinery in TGF-β induced EMT and metastasis in GC.

CEACAM5 targeted by miR-498 promotes cell proliferation, migration and epithelial to mesenchymal transition in gastric cancer

ObjectiveRecent studies have shown that carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) may serve as an independent predictor of advanced gastric cancer (GC). The purpose of this research is to explore the patterns of expression, functions, and upstream regulatory pathway of CEACAM5 in GC. MethodsThe levels of miR-498 and CEACAM5 expression in GC cells and tissues were measured via qRT-PCR. Wound-healing, CCK-8, and western blotting experiments were conducted for the evaluation of GC cell migration, proliferation, and epithelial-mesenchymal transition (EMT), respectively. The targeting relationship between miR-498 and CEACAM5 was validated via pull-down and luciferase reporter assays. Xenograft tumor mouse models were established to observe CEACAM5’s influence on the growth of tumors in vivo. ResultsElevated levels of CEACAM5 were detected among the GC cells and tissues. The results of the in vitro experiments revealed that the knockdown of CEACAM5 in GC cells significantly inhibited their proliferation, migration, and EMT. Moreover, CEACAM5 inhibition effectively hampered GC cell growth within the nude mice. Moreover, miR-498 directly targeted CEACAM5. MiR-498 downregulation had been observed among the cells and tissues of GC. The stimulation of GC cell proliferation, migration, and EMT, which had been engendered by CEACAM5 overexpression, was reversible through the overexpression of miR-498. ConclusionThe outcomes of this research suggest that miR-498 is capable of repressing the proliferation, migration, and EMT of GC cells through CEACAM5 downregulation.

Resveratrol inhibits TGF-β1-induced EMT in gastric cancer cells through Hippo-YAP signaling pathway.

To investigate the effects of resveratrol (RSVL) on epithelial-mesenchymal transition (EMT) and biological behaviors of gastric cancer cells. SGC-7901 cells were treated with RSVL, followed by TGF-β1 treatment for induction of EMT. Cell proliferation was tested by MTT assay, migration and invasion by Transwell and scratch assays, and Hippo-YAP signaling pathway activation by immunofluorescence. The RNA and protein expressions of E-cadherin, Vimentin, N-cadherin, and Snail were detected by qPCR and Western blot. A tumor model was constructed to examine the effect of RSVL on gastric tumor growth. RSVL inhibited the migration, invasion, and growth of gastric cancer cells in concentration- and time-dependent manners. RSVL inhibited TGF-β1-induced EMT of gastric cancer cells, which might relate to inactivation of the Hippo-YAP pathway. In the mouse tumor model, RSVL inhibited the EMT process by suppressing the Hippo-YAP pathway. RSVL inhibited EMT of gastric cancer cells probably by weakening the Hippo-YAP signaling pathway.

MicroRNA-15b-5p encapsulated by M2 macrophage-derived extracellular vesicles promotes gastric cancer metastasis by targeting BRMS1 and suppressing DAPK1 transcription

BackgroundExtracellular vesicles (EVs) derived from tumor-associated macrophages are implicated in the progression and metastasis of gastric cancer (GC) via the transfer of molecular cargo RNAs. We aimed to decipher the impact of microRNA (miR)-15b-5p transferred by M2 macrophage-derived EVs in the metastasis of GC.MethodsExpression of miR-15b-5p was assessed and the downstream genes of miR-15b-5p were analyzed. GC cells were subjected to gain- and loss-of function experiments for miR-15b-5p, BRMS1, and DAPK1. M2 macrophage-derived EVs were extracted, identified, and subjected to co-culture with GC cells and their biological behaviors were analyzed. A lung metastasis model in nude mice was established to determine the effects of miR-15b-5p on tumor metastasis in vivo.ResultsmiR-15b-5p was upregulated in GC tissues and cells as well as in M2 macrophage-derived EVs. miR-15b-5p promoted the proliferative and invasive potentials, and epithelial-mesenchymal transition (EMT) of GC cells. M2 macrophage-derived EVs could transfer miR-15b-5p into GC cells where it targeted BRMS1 by binding to its 3’UTR. BRMS1 was enriched in the DAPK1 promoter region and promoted its transcription, thereby arresting the proliferative and invasive potentials, and EMT of GC cells. In vivo experiments demonstrated that orthotopic implantation of miR-15b-5p overexpressing GC cells in nude mice displayed led to enhanced tumor metastasis by inhibiting the BRMS1/DAPK1 axis.ConclusionsOverall, miR-15b-5p delivered by M2 macrophage-derived EVs constitutes a molecular mechanism implicated in the metastasis of GC, and may thus be considered as a novel therapeutic target for its treatment.

Overexpression of Tetraspanin31 contributes to malignant potential and poor outcomes in gastric cancer.

Tetraspanin has important functions in many cancers by aggregating with various proteins that interact with intracellular signaling proteins. The molecular function of Tetraspanin31 (TSPAN31), located in the 12q14 amplified region in various cancers, remains unclear in gastric cancer (GC). We tested whether TSPAN31 acts as a cancer‐promoting gene through its activation or overexpression in GC. We analyzed seven GC cell lines and 189 primary tumors, which were curatively resected in our hospital between 2011 and 2013. Overexpression of the TSPAN31 protein was frequently detected in three GC cell lines (42.9%) and 62 primary GC specimens (32.8%). Overexpression of TSPAN31 was significantly correlated with lymphatic invasion, venous invasion, more advanced pT and pN stages, and a higher recurrence rate. Moreover, TSPAN31 positivity was an independent factor predicting worse patient outcomes (p = 0.0283, hazard ratio 3.97). Ectopic overexpression of TSPAN31 facilitated cell proliferation of GC cells, and knockdown of TSPAN31 inhibited cell proliferation, migration, invasion, and epithelial–mesenchymal transition of GC cells through the PI3K‐Akt pathway and increased cell apoptosis in a TP53 mutation‐independent manner. In vivo analysis also revealed knockdown of TSPAN31 suppressed tumor progression. In addition, knockdown of TSPAN31 improved chemosensitivity to cisplatin through the suppression of ABCC2. These findings suggest that TSPAN31 plays a crucial role in tumor‐malignant potential through overexpression, highlighting its utility as a prognostic factor and a potential therapeutic target in GC.

MiR-137 Modulates Human Gastric Cancer Cell Proliferation, Apoptosis, and Migration by Targeting EZH2

Gastric cancer (GC) is a malignancy of the digestive tract with rapid progress, poor prognosis, and low survival rate. The aberrant expression of microRNA (miRNA) is closely related to the tumorigenesis and progression of GC. The purpose of this study was to investigate the effects of miR-137 on the proliferation, apoptosis, and migration of GC cells. Bioinformatics analysis revealed that EZH2 expression in GC based on The Cancer Genome Atlas (TCGA) dataset was dramatically increased, miR-137 expression was down-regulated, and miR-137 was remarkably negatively correlated with EZH2 in GC. Next, it was found that EZH2 expression was significantly increasing and miR-137 was significantly decreasing by quantitative polymerase chain reaction (qRT-PCR) in GC clinical specimens. In addition, miR-137 expression in GC cell lines was significantly lower than that in normal gastric parietal cells. TargetScan and star-Base were employed to predict that EZH2 was a potential target of miR-137, and subsequent luciferase reports confirmed this prediction. Western blot assay demonstrated that up-regulation of miR-137 decreased EZH2 expression in BGC-823 cells, whereas silenced miR-137 enhanced EZH2 expression in SGC-7901 cells. The gain/loss-of-function indicates that miR-137 regulates the proliferation, apoptosis, migration and epithelial-mesenchymal transition of GC cells. In conclusion, our findings indicate that miR-137 restrains migration and proliferation and induces apoptosis partially through negatively regulating the expression of EZH2 in GC cells.

Effects of SDF-1/CXCR7 on the Migration, Invasion and Epithelial-Mesenchymal Transition of Gastric Cancer Cells.

We found that SDF-1/CXCR7 axis played an important role in the growth and proliferation of gastric cancer in the previous studies. The objectives of this study were to explore the effects of SDF-1/CXCR7 on the metastatic ability of gastric cancer cells and the possible mechanisms. CXCR7 expression in SGC-7901 gastric cancer cells was stably knocked down via lentiviral vectors. The cell migration and invasion abilities were detected by transwell migration and invasion assays. The expressions of matrix metalloproteinase 2 (MMP-2), MMP-9, vascular endothelial growth factor (VEGF), epithelial-mesenchymal transition (EMT) markers and Akt phosphorylation were detected with real-time PCR and/or western blot. We found that SDF-1 markedly enhanced the migration and invasion abilities of SGC-7901 gastric cancer cells; CXCR7 knockdown inhibited these effects. SDF-1/CXCR7 increased the expressions of MMP-2, MMP-9 and VEGF. SDF-1/CXCR7 also downregulated E-cadherin expression but upregulated N-cadherin, vimentin and Snail expressions, suggesting that SDF-1/CXCR7 could promote the development of EMT in gastric cancer cells. Furthermore, SDF-1/CXCR7 could promote Akt phosphorylation. Our results indicated that SDF-1/CXCR7 enhanced the migration, invasion and EMT of gastric cancer cells and thus CXCR7 supression may be a strategy for inhibiting gastric cancer metastasis.