Normal Gastric Mucosal Cells Research Articles

MiR-449a/b negatively regulates E2F1 to suppress proliferation of gastric cancer cells

To investigate the possible role of miR-449a/b in the occurrence of gastric cancer. The expression of miR-449a/b and E2F1 mRNA in gastric cancer cells BGC-823 and gastric mucosal cells GES-1 were detected with qRT-PCR. miR-449a/b mimics or a negative control was transiently transfected into BGC-823 cells, and the changes in cell proliferation, apoptosis, and migration ability were assessed using CCK-8 assay, flow cytometry, and scratch wound healing assay, respectively. Western blotting was used to observe the effects of miR-449a/b upregulation on its target gene expression. The effects of transfection with an E2F1-over-expressing plasmid or an empty plasmid were analyzed on the expression level of miR-449a/b in BGC-823 cells using qRT-PCR and digital PCR. The gastric cancer cell line BGC-823 showed significantly a lowered expression of miR-449a/b compared with the normal gastric mucosal cell line GES-1 (P < 0.01). Overexpression of miR-449a/b obviously inhibited the proliferation and migration and promoted apoptosis of BGC-823 cells (P < 0.05). Overexpression E2F1 in the cells resulted in significantly up-regulated expression of miR-449a/b (P < 0.001). Upregulation of miR-449a/b caused significant down-regulation of its direct target genes CDK4 and CDK6 and also of the expression of E2F1 protein via the CDKs-pRb-E2F1 signaling pathway. The low expression of miR-449a/b and the high expression of E2F1 are both involved in the occurrence and progression of gastric cancer, and miR-449a/b negatively regulates E2F1 to inhibit the proliferation of gastric cancer cells.

Effects of ginsenoside Rg5 on cell cycle and invasion of gastric cancer

To investigate the effects of ginsenoside Rg5 on the proliferation, cycle and invasion of gastric carcinoma cell lines, providing experimental evidence for the anti-tumor mechanism of ginsenoside Rg5. In this experimental study, the human immortalized normal gastric mucosa cell GES-1 and gastric adenocarcinoma cell lines AGS and MKN-45 were treated with Rg3 and Rg5 at the concentrations of 10, 20, 30, 40 and 50 μmol/L for 24 h, 3 parallel holes were set for each group. A cell viability test, cell cycle analysis, transwell assay, ELISA and immunoblotting were performed. The viabilities of AGS and MKN-45 were suppressed by Rg3 and Rg5 in a concentration-dependent manner. The activity of Rg5 against gastric cancer cells was stronger than that of Rg3, and its toxicity to GES-1 was lower than that of Rg3. After the treatment of 20 μmol/L of Rg5 for 24 h, Rg5 could generate cell cycle S phase arresting by decreasing the CyclinA1/cyclin-dependent kinase 2 (CDK2)/proliferating cell nuclear antigen (PCNA) complex production and increasing the P21CIPI. Rg5 inhibited the migration of MNK-45 cells by reducing the expressions of MMP2 and MMP9. WB results showed that Rg5 inhibited the proliferation and migration of gastric cancer mainly by inhibiting the expression of Notch1 protein to regulate its downstream cycle and invasion related proteins. These results suggest that Rg5 exhibits stronger anti-cancer activity than Rg3 in gastric cancer cells, and has higher anti-gastric cancer cell activity than Rg3 and inhibits cell proliferation and migration by regulating the Notch1 pathway.

LETM1 Promotes Gastric Cancer Cell Proliferation, Migration, and Invasion via the PI3K/Akt Signaling Pathway.

PurposeGlobally, there is a high incidence of gastric cancer (GC). Leucine zipper-EF-hand containing transmembrane protein 1 (LETM1) is reported to play a vital role in several human malignancies. However, there is limited understanding of the role of LETM1 in GC. This study aims to investigate the effects of LETM1 on proliferation, migration, and invasion of GC cells.Materials and MethodsThe expression levels of LETM1 in the normal gastric mucosal epithelial cells (GES-1) and GC cells were analyzed by quantitative real-time polymerase chain reaction and western blotting. CCK-8, wound healing, and Transwell invasion assays were performed to evaluate the effect of LETM1 knockdown or overexpression on the proliferation, migration, and invasion of the GC cells, respectively. Additionally, the effect of LETM1 knockdown or overexpression on GC cell apoptosis was determined by flow cytometry. Furthermore, the effect of LETM1 knockdown or overexpression on the expression levels of PI3K/Akt signaling pathway-related proteins was evaluated by western blotting.ResultsThe GC cells exhibited markedly higher mRNA and protein expression levels of LETM1 than the GES-1 cells. Additionally, the knockdown of LETM1 remarkably suppressed the GC cell proliferation, migration, and invasion, and promoted the apoptosis of GC cells, which were reversed upon LETM1 overexpression. Furthermore, the western blotting analysis indicated that LETM1 facilitates GC progression via the PI3K/Akt signaling pathway.ConclusionsLETM1 acts as an oncogenic gene to promote GC cell proliferation, migration, and invasion via the PI3K/Akt signaling pathway. Therefore, LETM1 may be a potential target for GC diagnosis and treatment.

Physiological Significance of Ion Transporters and Channels in the Stomach and Pathophysiological Relevance in Gastric Cancer

Gastric cancer (GC) is a highly invasive and fatal malignant disease that accounts for 5.7% of new global cancer cases and is the third leading cause of cancer-related death. Acid/base homeostasis is critical for organisms because protein and enzyme function, cellular structure, and plasma membrane permeability change with pH. Various ion transporters are expressed in normal gastric mucosal epithelial cells and regulate gastric acid secretion, ion transport, and fluid absorption, thereby stabilizing the differentiation and homeostasis of gastric mucosal epithelial cells. Ion transporter dysfunction results in disordered ion transport, mucosa barrier dysfunction, and acid/base disturbances, causing gastric acid-related diseases such as chronic atrophic gastritis (CAG) and GC. This review summarizes the physiological functions of multiple ion transporters and channels in the stomach, including Cl− channels, Cl−/HCO3− exchangers, sodium/hydrogen exchangers (NHEs), and potassium (K+) channels, and their pathophysiological relevance in GC.

SNHG7 accelerates cell migration and invasion through regulating miR-34a-Snail-EMT axis in gastric cancer

ABSTRACT Small nucleolar RNA host gene 7 (SNHG7) is a newly recognized oncogenic Long non-coding RNA (lncRNA) in most human cancers. In gastric cancer, SNHG7 has been suggested to enhance cell proliferation and suppressed apoptosis through down-regulating P15 and P16 expression, but the effect of SNHG7 on gastric cancer cell migration and invasion was still unknown. In our study, we aimed to estimate the relationship between SNHG7 expression and clinical and pathological characteristics, and explore the effect of SNHG7 on gastric cancer cell migration and invasion. In our study, the levels of SNHG7 expression in gastric cancer tissues and cell lines were severally higher than in normal adjacent tissues and gastric mucosal epithelial cells. Moreover, high SNHG7 expression was positively correlated with TNM stage, depth of invasion, lymph-node metastasis and distant metastasis in gastric cancer patients. Furthermore, the multivariate Cox proportional hazard analysis further showed high SNHG7 expression was an independent poor prognostic factor for overall survival in gastric cancer patients. The studies in vitro revealed that SNHG7 directly binds to miR-34a and negatively regulates miR-34a expression, and SNHG7 enhances gastric cancer cell migration and invasion through suppressing miR-34a-Snail-EMT axis. In conclusion, SNHG7 functions as oncogenic lncRNA in gastric cancer and may be a potential therapeutic target for gastric cancer patients. Abbreviations: lncRNA: Long non-coding RNA; SNHG7: Small nucleolar RNA host gene 7; EMT: Epithelial mesenchymal transition; TNM: Tumor-Lymph Node-Metastasis.

Gramicidin inhibits human gastric cancer cell proliferation, cell cycle and induced apoptosis

BackgroundGastric cancer is a common malignant tumor with high morbidity and mortality worldwide, which seriously affects human health. Gramicidin is a short peptide antibiotic which could be used for treating infection induced by bacteria or fungi. However, the anti-cancer effect of gramicidin on gastric cancer cells and its underlying mechanism remains largely unknown.ResultsGastric cancer cells SGC-7901, BGC-823 and normal gastric mucosal cells GES-1 were treated with different concentrations of gramicidin respectively. The results of CCK-8 experiment revealed cellular toxicity of gramicidin to cancer cells while cell colony formation assay showed that gramicidin significantly inhibited the proliferation of gastric cancer cells, but had little effect on normal gastric mucosal cells. In addition, the wound healing assay showed that gramicidin inhibited the migration of SGC-7901 cell. Meanwhile, apoptosis and cell cycle analysis revealed that gramicidin induced cell apoptosis with G2/M cell cycle inhibition. Furthermore, western blot analysis demonstrated that gramicidin down-regulated the expression of cyclinD1 and Bcl-2 as well as the FoxO1 phosphorylation.ConclusionsThe current study illustrated the anti-tumor activity of gramicidin on gastric cancer cells, providing a possibility for gramicidin to be applied in clinical practice for the treatment of gastric cancer.

Oncogenic USP22 supports gastric cancer growth and metastasis by activating c-Myc/NAMPT/SIRT1-dependent FOXO1 and YAP signaling.

In this study, we investigated the role of ubiquitin-specific protease 22 (USP22) in the growth and progression of gastric cancer (GC). USP22 mRNA and protein levels were significantly higher in GC tissue samples and GC cell lines than in adjacent noncancerous tissue samples and a normal gastric mucosal epithelial cell line (GES1), respectively. USP22 knockdown significantly decreased in vitro survival, proliferation, migration, and invasiveness of GC cells compared with the controls. Western blot analysis of control and USP22-silenced GC cells showed that USP22 modulates the c-Myc/NAMPT/SIRT1-dependent FOXO1 and YAP signaling pathways. Subcutanenous injection of USP22-silenced GC cells into SCID mice generated significantly smaller xenograft tumors than did control cells. Moreover, USP22-silenced GC cells showed less lung metastasis than the controls following tail vein injection in SCID mice. In addition, high USP22 expression correlated positively with tumor size, advanced stage and metastasis, and correlated negatively with tumor differentiation and prognosis in GC patients. These results show that USP22 regulates growth and progression of GC via the c-Myc/NAMPT/SIRT1-dependent FOXO1 and YAP signaling pathways.

MicroRNA-320a suppresses tumor progression by targeting PBX3 in gastric cancer and is downregulated by DNA methylation.

BACKGROUNDEctopic expression of miRNAs promotes tumor development and progression. miRNA (miR)-320a is downregulated in many cancers, including gastric cancer (GC). However, the mechanism underlying its downregulation and the role of miR-320a in GC are unknown.AIMTo determine expression and biological functions of miR-320a in GC and investigate the underlying molecular mechanisms.METHODSQuantitative real-time polymerase chain reaction (PCR) was used to determine expression of miR-320a in GC cell lines and tissues. TargetScanHuman7.1, miRDB, and microRNA.org were used to predict the possible targets of miR-320a, and a dual luciferase assay was used to confirm the findings. Western blotting was used to detect the protein levels of pre-B-cell leukemia homeobox 3 (PBX3) in GC cells and tissue samples. Cell Counting Kit-8 proliferation, Transwell, wound healing, and apoptosis assays were performed to analyze the biological functions of miR-320a in GC cells. Methylation-specific PCR was used to analyze the methylation level of the miR-320a promoter CpG islands. 5-Aza-2’-deoxycytidine (5-Aza-CdR) and trichostatin A (TSA) were used to treat GC cells.RESULTSmiR-320a expression was lower in GC cell lines and tissues than in the normal gastric mucosa cell line GES-1 and matched adjacent normal tissues. miR-320a overexpression suppressed GC cell proliferation, invasion and migration, and induced apoptosis. PBX3 was a target of miR-320a in GC. The methylation level of the miR-320a promoter CpG islands was elevated and this was partly reversed by 5-Aza-CdR and TSA.CONCLUSIONmiR-320a acts as a tumor suppressor and inhibits malignant behavior of GC cells, partly by targeting PBX3. DNA methylation is an important mechanism associated with low expression of miR-320a.

Long non-coding RNA LUCAT1 promotes proliferation and invasion in gastric cancer by regulating miR-134-5p/YWHAZ axis

PurposeThe aim of this study was to research the function of lncRNA LUCAT1 in gastric cancer. MethodsHuman gastric cancer tissues and paracancer tissues were obtained from 98 patients undergoing surgical resection in our hospital. The human gastric cancer cell lines (HGC27, BGC823, MGC803, SGC7901 and AGS), and normal gastric mucosal cell line GSE1 were used to research the role of lncRNA LUCAT1. ShRNAs specifically targeting lncRNA LUCAT1, miR-134-5p mimic, miR-134-5p inhibitor and their related controls were transfected into cells. Quantitative real-time PCR was used to detect the expression of lncRNA LUCAT1, miR-134-5p and YWHAZ. The cell proliferation of SGC7901 cells was determined by CCK8 kit. Colony formation assay was undertaken. Cell apoptosis assay was processed using the Annexin V-FITC / propidium iodide (annxinV/PI) apoptosis detection kit. Migration and invasion were detected by transwell assay. Tumor xenograft model was conducted to calculate the size and weight of the tumors. Luciferase reporter assay was used to confirm the interactions among lncRNA LUCAT1, miR-134-5p and YWHAZ. ResultsLncRNA LUCAT1 was confirmed to be highly expressed in gastric cancer. Patients with high LUCAT1 level displayed short overall survival and disease-free survival periods. LUCAT1 knockdown or miR-134-5p overexpression decreased the proliferation, colony formation, migration and invasion of SGC7901 cells. ConclusionsLncRNA LUCAT1 could promote proliferation and invasion of gastric cancer by regulating miR-134-5p/YWHAZ axis.

Long non-coding RNA CASC19 is associated with the progression and prognosis of advanced gastric cancer.

Evidence indicates that aberrantly expressed long non-coding RNAs (lncRNAs) are involved in the development and progression of advanced gastric cancer (AGC). Using RNA sequencing data and clinical information obtained from The Cancer Gene Atlas, we combined differential lncRNA expression profiling and weighted gene co-expression network analysis to identify key lncRNAs associated with AGC progression and prognosis. Cancer susceptibility 19 (CASC19) was the top hub lncRNA among the lncRNAs included in the gene module most significantly correlated with AGC’s pathological variables. CASC19 was upregulated in AGC clinical samples and was significantly associated with higher pathologic TNM stage, pathologic T stage, lymph node metastasis, and poor overall survival. Multivariable Cox analysis confirmed that CASC19 overexpression is an independent prognostic factor for overall survival. Furthermore, quantitative real-time PCR assay confirmed that CASC19 expression in four human gastric cancer cells (AGS, BGC-823, MGC-803, and HGC-27) was significantly upregulated compared with human normal gastric mucosal epithelial cell line (GES-1). Functionally, CASC19 knockdown inhibited GC cell proliferation and migration in vitro. These findings suggest that CASC19 may be a novel prognostic biomarker and a potential therapeutic target for AGC.

Effect of peroxiredoxin 1 on apoptosis and autophagy of human gastric cancer cells and possible mechanism

Objective To investigate the effect and molecular mechanism of peroxiredoxin 1 (PRDX1) in human gastric cancer cell lines. Methods The expression of PRDX1 was detected in gastric cancer cell lines SGC7901, AGS and the normal gastric mucosa cell line GES-1 with real-time quantitative polymerase chain reaction (Real-time PCR). Small interfering RNA to PRDX1 was synthetized for the transfection with lentivirus vector of LV-PRDX1-small interfering RNA (siRNA), which was transfected into AGS. Methyl thiazol tetrazolium (MTT) assay was used to test activity of cells. Flow cytometry (FCM) was used to detect the apoptosis rate and mitochondrial trans-membrane potential. Real-time PCR and Western blotting were used to detect the expression of mRNAs and proteins associated with apoptosis and autophagy. Results The expression of PRDX1 mRNA (1.049±0.124, 1.597±0.103) and proteins (0.873±0.135, 1.083±0.204) in SGC7901, AGS cells was significantly higher than that in GES-1 cells (mRNA: 0.451±0.060, and protein: 0.305±0.022), and the difference was significant (F=200.162, 48.432, P 0.05), and the expression of Beclin-1 and LC-3Ⅱ/LC-3Ⅰ increased significantly (F=30.332, 24.260, P<0.01). Conclusion PRDX1 was up-regulated in gastric cancer cells, and inhibition of PRDX1 can regulate apoptosis and autophagy via regulating apoptosis and autophagy associated genes. Key words: Gastric cancer; Peroxiredoxin1; Autophagy; Target gene

Overexpression of lncRNA AFAP1-AS1 promotes cell proliferation and invasion in gastric cancer.

Long non-coding RNA (lncRNA) actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1) has been revealed to be associated with certain types of cancer. However, whether the lncRNA AFAP1-AS1 is involved in the development and progression of gastric cancer (GC) remains unknown. The present study investigated the clinical significance and biological functions of AFAP1-AS1 in GC. The expression levels of lncRNA AFAP1-AS1 in 52 patients with GC, and in 1 normal gastric mucosal cell line and 3 GC cell lines, were evaluated by reverse transcription quantitative polymerase chain reaction analysis. Small interfering RNAs were used to suppress AFAP1-AS1 expression in GC cell lines. The results indicated that AFAP1-AS1 expression levels were significantly increased in GC tissues and cell lines compared with the corresponding noncancerous tissues and normal gastric cells. In addition, the patients with GC with increased AFAP1-AS1 expression exhibited an advanced clinical stage and an association with the occurrence of lymph node metastasis compared with those with decreased AFAP1-AS1 expression. In vitro assays demonstrated that knockdown of AFAP1-AS1 decreased levels of cell proliferation and migration. In addition, the results of flow cytometry demonstrated that knockdown of AFAP1-AS1 caused cell cycle arrest. In conclusion, AFAP1-AS1 is a novel molecule involved in GC progression, which may be a potential prognostic biomarker and target for therapeutic intervention.

MiR-503 suppresses cell proliferation and invasion of gastric cancer by targeting HMGA2 and inactivating WNT signaling pathway

BackgroundAbnormal expression of microRNAs (miRNAs) is related to human carcinogenesis. Although previous studies have shown that miR-503 expression in gastric cancer (GC) is downregulated, however, the underlying molecular mechanism for miR-503 involved in gastric cancer development is still largely unknown.MethodsThe relative expression of miR-503 in GC tissues and adjacent normal tissues was examined using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) analyses. In vitro, cell proliferation and invasion were evaluated by using CCK8, cell colony and transwell invasion assays. In vivo, xenograft tumor model was constructed to assess miR-503 expression whether affects tumor growth or not. Luciferase reporter assay, qRT-PCR and western blot assay were used to demonstrate HMGA2 is a target of miR-503.ResultsWe demonstrated that miR-503 expression was significantly downregulated in GC tissues and cell lines compared to adjacent normal tissues and normal gastric mucosa cell lines, respectively. Lower miR-503 expression associated with tumor size, lymph node metastasis, and predicted a poor overall survival (OS) time in GC patients. Subsequently, in vitro, gain-function and loss-function assays confirmed that miR-503 overexpression significantly suppressed GC cell proliferation, colony formation and cell invasion, while decreased miR-503 expression had an adverse effect in GC cells. Furthermore, we found that miR-503 specifically targeted the 3′-UTR regions of HMGA2 mRNA and suppressed its protein expression. Overexpression of HMGA2 could reverse the miR-503 mediated inhibition of GC cell proliferation and invasion. In vivo, miR-503 overexpression dramatically reduced tumor growth. Moreover, we demonstrated that miR-503 suppressed WNT/β-catenin signaling by elevating GSK-3β and p-β-catenin expression, but decreased p-GSK-3β and β-catenin expression in GC cells.ConclusionThese results provide that miR-503 expression acts as a predictor for GC prognosis and may have a potential application in GC therapy.

Relationship between microRNA-27a and efficacy of neoadjuvant chemotherapy in gastric cancer and its mechanism in gastric cancer cell growth and metastasis.

Objective: The aim of the present study is to investigate the relationship between microRNA-27a (miR-27a) and the efficacy of neoadjuvant chemotherapy in gastric cancer (GC) and its mechanism in the growth and metastasis of GC cells.Methods: The expression of miR-27a in serum of 74 GC patients received neoadjuvant chemotherapy was detected by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Clinical value and prognosis of miR-27a expression in predicting the efficacy of neoadjuvant chemotherapy in GC were evaluated. Besides, GC cells with low miR-27a expression were transfected with miR-27a mimics, and cells with high miR-27a expression were transfected with miR-27a inhibitors and secreted frizzled-related protein 1 (SFRP1) siRNA. A series of experiments were applied for the determination of cell viability, invasion and migration of GC cells.Results: After neoadjuvant chemotherapy, the expression of miR-27a in serum of GC patients decreased significantly. Additionally, the expression of miR-27a in GC cell line was significantly higher than that in normal gastric mucosa cell line. Meanwhile, after down-regulating the expression of miR-27a in GC cells, the mRNA and protein expression of SFRP1 increased, the proliferation rate of cells slowed down, and the ability of invasion and migration decreased. Furthermore, combined with low expression of miR-27a and SFRP1, the proliferation rate of GC cells increased and the ability of invasion and migration increased.Conclusion: Collectively, our study highlights that the high expression of miR-27a indicates the poor efficacy and prognosis of neoadjuvant chemotherapy in GC patients. Down-regulation of miR-27a can inhibit the growth and metastasis of GC cells via up-regulation of SFRP1.

Synthesis and antiproliferative activity of novel 4-azasteroidal-17-hydrazone derivatives

A new series of 4-azasteroidal-17-hydrazone derivatives have been synthesized from androstenedione. Their structures were characterized by analysis and spectroscopic data. The antiproliferative activity of synthesized compounds against three cancer cells (human lung adenocarcinoma, human oesophageal cervical cancer, human gastric adenocarcinoma) and a normal cell line (human gastric mucosal) was investigated. The studies show that the compound bearing a naphthyl group displayed the same antiproliferative activity in vitro against tested cells as cis-platin did (a positive control). Most of the compounds show very weak toxicity towards normal human gastric mucosal cell line.

Mitochondria in gastric epithelial cells are the key targets for NSAIDs-induced injury and NGF cytoprotection.

Gastric epithelial cells are important components of mucosal protection and targets of nonsteroidal anti-inflammatory drugs (NSAIDs)-induced injury. Diclofenac (DFN) is one of the most widely used NSAIDs; however, even its short-term use can induce gastric erosions and ulcers. Nerve growth factor (NGF) has been reported to act not only on neuronal cells but also on endothelial cells; however, its action on gastric epithelial cells is unknown. This study was aimed to determine, whether NGF can protect gastric epithelial cells against DFN-induced injury, and to determine the underlying molecular mechanisms with a focus on mitochondria, survivin, and insulin-like growth factor 1 (IGF-1). Cultured normal rat gastric mucosal epithelial cells 1 (RGM1) were treated with phosphate-buffered saline (PBS; control), NGF (100 ng/mL) and/or DFN (0.25-1.00 mM) for 4 hours. We examined: (1) cell injury by confocal microscopy; (2) cell death/survival using Calcein AM live cell tracking dye; (3) mitochondrial structure and membrane potential function using MitoTracker in live cells; and (4) expression of NGF, its receptor - tropomyosin receptor kinase A (TrkA), survivin and IGF-1 by immunostaining. DFN treatment of RGM1 cells for 4 hours caused extensive cell injury, mitochondrial disintegration, reduced cell viability (from 94 ± 3% in controls to 14 ± 4% in 0.5 mM DFN-treated cells; P < 0.001), and expression of survivin and IGF-1. NGF treatment significantly increased survivin and IGF-1 expression by 41% and 75%, respectively versus PBS controls. Pretreatment with NGF before DFN treatment reduced mitochondrial damage and cell death by 73% and 82%, respectively versus treatment with DFN alone (all P < 0.001). This study also showed the presence of high-affinity TrkA receptors in the plasma membrane and mitochondria of RGM1 cells indicating novel actions of NGF.

Long Noncoding RNA (lncRNA) MIR22HG Suppresses Gastric Cancer Progression through Attenuating NOTCH2 Signaling.

BackgroundLong noncoding RNAs (lncRNAs) are important regulators in human disease, including cancers. LncRNA MIR22HG has been shown to inhibit the progression of endometrial carcinoma, lung cancer, and hepatocellular carcinoma. Its role in gastric cancer is unclear. This study investigated MIR22HG effects on gastric cancer.Material/MethodsGastric cancer tissues (n=43) and adjacent normal tissues (n=21) were collected. Patients’ 5-year overall survival rate was analyzed. Human normal gastric mucosal cell line (GES-1) and gastric cancer cell lines (MKN-45, AGS, SGC-7901) were cultured. AGS and MKN-45 cells were transfected by pcDNA3 empty vector, pcDNA3-MIR22HG overexpression vector, MIR22HG siRNA and its negative control, NOTCH2 siRNA and its negative control, respectively. Proliferation was explored by CCK-8 assay. Migration and invasion were explored by Transwell. qRT-PCR and western blot were used to investigate mRNA and proteins expression, respectively.ResultsMIR22HG expression was decreased in gastric cancer tissues and cells (P<0.05). Low MIR22HG expression indicated lower 5-year overall survival rate (P<0.05). Upregulation of MIR22HG inhibited AGS and MKN-45 cell proliferation, migration and invasion (all P<0.05). Downregulation of MIR22HG elevated AGS and MKN-45 cell proliferation, migration, and invasion (all P<0.05). MIR22HG negatively regulated NOTCH2 signaling. Silencing MIR22HG elevated HEY1 and nucleus NOTCH2 expression. Silencing of NOTCH2 suppressed AGS and MKN-45 cells proliferation, migration and invasion (all P<0.05).ConclusionsLncRNA MIR22HG suppressed gastric cancer progression through attenuating NOTCH2 signaling.

Functional characterization of a potent anti-tumor polysaccharide in a mouse model of gastric cancer

AimsNatural polysaccharides are emerging as a new class of immunomodulatory agents due to their potent immunostimulatory effects and suitable biocompatibility. The aim of this study was to identify potent and selective anticancer activity of a bioactive polysaccharide. Materials and methodsIn vitro, viability assay was performed to screen 16 of bioactive polysaccharides in a panel of normal and cancer cell lines. Foci formation, soft agar, BrdU incorporation, cell cycle analyses, and β-galactosidase staining were performed to validate the screening results. In vivo, both murine gastric cancer syngeneic and a human gastric tumor xenografts models were applied. Tumor histology, immunohistochemical staining, cytokine array and flow cytometry analyses were assayed. Key findingsBSP (bamboo shaving polysaccharides) was identified as the most selective polysaccharide for inhibiting the growth of six gastric cancer cell lines while having no toxic effect on normal gastric mucosal cells. Similarly, BSP had more potent killing effect on a subset of human stomach cancer cells than liver or lung cancer cells. In vivo, BSP significantly inhibited tumor growth and prolonged the survival of mice bearing a gastric tumor; these effects are mediated by tumor cell apoptosis and remodeling of the tumor microenvironment by boosting both immune cell subpopulations and cytokine production in murine gastric cancer syngeneic model. A significant decrease of F4/80-positive tumor-associated macrophages was also observed. SignificanceThe findings of this study suggest that the potent and selective anti-tumor activity of bioactive polysaccharides such as BSP warrants clinical testing for the treatment of gastric cancer.

LncRNA LOC554202 promotes proliferation and migration of gastric cancer cells through regulating p21 and E-cadherin.

To explore whether long noncoding RNA (lncRNA) LOC554202 could regulate proliferative and migratory abilities of gastric cancer (GC) cells. Expression level of LOC554202 in GC cell lines HGC-27 and MGC-803, as well as normal gastric mucosal cell line GES-1 was detected by quantitative real-time polymerase chain reaction (qRT-PCR). LOC554202 knockdown or overexpression in HGC-27 and MGC-803 cells was achieved by transfection of LOC554202-siRNA or pcDNA-LOC554202, respectively. Cell cycle in GC cells was accessed by flow cytometry. Migratory ability of GC cells was determined by wound healing assay and transwell assay. Finally, protein expressions of p21 and E-cadherin in GC cells were detected by Western blot. LOC554202 expression was higher in GC cells than that of gastric mucosal cells (p<0.01). Overexpression of LOC554202 in MGC-803 cells enhanced proliferative and migratory abilities, but decreased protein expressions of p21 and E-cadherin (p<0.01). On the contrary, LOC554202 overexpression in HGC-27 cells decreased proliferative and migratory abilities, but increased protein expressions of p21 and E-cadherin (p<0.01). LncRNA LOC554202 is highly expressed in GC cells. It could promote proliferative and migratory abilities by downregulating expression levels of p21 and E-cadherin in GC cells.

Effect of microRNA-1 on the expression of angiogenesis-related factors in gastric cancer cells

Objective To observe the role of microRNA (miRNA, miR)-1 in the development of gastric cancer. Methods Real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) was used to detect the expression of miR-1 in human gastric cancer cell lines SGC7901 and BGC823. The plasmid expressing miR-1 was transfected into gastric cancer cells by transient transfection to detect the effect of miR-1 on the proliferation of gastric cancer cells. The effects of over-expressed miR-1 on angiogenesis-related factors vascular endothelial growth factor (VEGF)-A and EDN-1 in gastric cancer cells were detected by Western blotting. Double-reporter assay was used to analyze miR-1 interaction with VEGF-A and EDN1 3’untranslated regions (3’UTR). Results Compared with normal gastric mucosal epithelial cells, miR-1 was down-regulated in gastric cancer cells (P=0.000), and miR-1 inhibited VEGF-A and EDN-1 in proteins levels by binding to specific sites of VEGF-A and EDN-1 3’UTR, thereby inhibiting the proliferation of gastric cancer cells. Conclusion miR-1 inhibits tumors by inhibiting angiogenesis-related factors in human gastric cancer. Key words: Gastric cancer; MicroRNA-1; Vascular endothelial growth factor