Invasion Of Human Gastric Cancer Cells Research Articles

Resveratrol inhibits the proliferation, invasion, and migration, and induces the apoptosis of human gastric cancer cells through the MALAT1/miR-383-5p/DDIT4 signaling pathway.

We aimed to study the effects and potential mechanism of resveratrol (RS) in gastric cancer (GC). The human GC cell line SGC7901 was treated with different concentrations of RS (0, 1, 5 µM) for 24 hours. The messenger ribonucleic acid or protein expressions levels of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), micro ribonucleic acid-383-5p (miR-383-5p), and DNA damage-inducible transcript 4 (DDIT4) in GC cells were determined by Western blot and quantitative real-time polymerase chain assays. Cells were then transfected with miR-383-5p inhibitor (inhibitor), inhibitor negative control (NC), MALAT1-interfering RNA (si-MALAT1), si-DDIT4 and negative interference control (si-NC). The Cell Counting Kit-8 method, scratch assay, and transwell assay were performed to evaluate cell proliferation, migration, and invasion. Additionally, flow cytometry was used to examine apoptosis, and the target relationship was examined by a luciferase-reporter gene analysis. RS treatment downregulated the expression of MALAT1, repressed cell proliferation, inhibited cell migration and invasion (all P<0.05), and induced apoptosis (P<0.05) in GC cells. When the cells were treated with RS and inhibited the expression of MALAT1 meanwhile, the above anti-cancer effects were more significant (all P<0.05). Target prediction and the luciferase-reporter gene analysis showed that MALAT1 targeted miR-383-5p (P<0.05). When suppressing the expression of MALAT1 and miR-383-5p, the anti-cancer effects caused by the silencing of MALAT1 were absent (all P<0.05). We also found that miR-383-5p targeted DDIT4 protein. When the expression of miR-383-5p and DDIT4 in the GC cells was inhibited, the promoting cancer effects caused by the inhibition of miR-383-5p were reversed (all P<0.05). This study found that RS inhibited the proliferation, migration, and invasion of human GC cells through the metastasis-associated lung adenocarcinoma transcript 1 (MALAT1)/miR-383-5p/DDIT4 pathway and induced apoptosis.

SIRT2 Promotes the Migration and Invasion of Gastric Cancer through RAS/ERK/JNK/MMP-9 Pathway by Increasing PEPCK1-Related Metabolism

Metastasis is the most important feature of gastric cancer (GC) and the most widely recognized reason for GC-related deaths. Unfortunately, the underlying mechanism behind this metastasis remains unknown. Mounting evidence suggests the dynamic regulatory role of sirtuin2 (SIRT2), a histone deacetylase (HDAC), in cell migration and invasion. The present study aims to evaluate the biological function of SIRT2 in GC and identify the target of SIRT2 as well as evaluate its therapeutic efficacy. We found that SIRT2 was upregulated in GC tissues compared to adjacent normal tissues, and this was correlated with reduced patient survival. Although CCK8 and colony-formation assays showed that SIRT2 overexpression marginally promoted proliferation in GC cell lines, SIRT2 knockdown or treatment with SirReal2 decreased the migration and invasion of GC cells. We demonstrated both in vitro and in vivo that SirReal2 could inhibit the deacetylation activity of SIRT2 and its downstream target PEPCK1, which is related to mitochondrial metabolism and RAS/ERK/JNK/MMP-9 pathway. Taken together, these results demonstrate for the first time that SirReal2 selectively targets SIRT2 and decreases migration as well as invasion in human GC cells. SirReal2 therefore shows promise as a new drug candidate for GC therapy.

Melanoma differentiation-associated gene-7 suppresses human gastric cancer cell invasion and migration.

Gastric cancer is one of the most common types of cancer in the world. Patients with gastric cancer often respond poorly to conventional chemotherapies, therefore more comprehensive therapy is required. Melanoma differentiation-associated gene-7 (MDA-7), also termed interleukin-24, is a potent tumor suppressor gene. Numerous studies have demonstrated that MDA-7 suppresses the growth and induces the apoptosis of cancer cells. In the present study, the MDA-7 gene was transfected into human gastric cancer AGS cells using adenovirus. Transwell and wound healing assays were performed to evaluate AGS cell invasion and migration, respectively. Western blotting was used to detect the expression of epithelial (E)-cadherin, cluster of differentiation (CD)44 and matrix metalloproteinase (MMP)-2 and MMP-9 proteins. A recombinant virus package was successfully constructed, and it was verified using western blotting that exogenous MDA-7 was highly expressed in the AGS cells. MDA-7 overexpression inhibited invasion and migration, decreased CD44, MMP-2 and MMP-9 expression, and increased epithelial (E-)cadherin expression in the AGS cells. Results of the present study revealed that MDA-7 inhibits gastric cancer invasion and metastasis by inhibiting CD44, MMP-2 and MMP-9 expression and by promoting E-cadherin expression.

MiR-182-5p improves the viability, mitosis, migration, and invasion ability of human gastric cancer cells by down-regulating RAB27A.

We investigated the effect of miR-182-5p on the viability, proliferation, invasion, and migration ability of human gastric cells by regulating the expression of RAB27A. Real-time PCR assay was used to detect the expression of miR-182-5 and RAB27A in human gastric carcinoma tissues, para-carcinoma tissues, and different cell lines. Western blotting was also used to determine the RAB27A expression in both tissues and cell lines. We chose the HGC-27 cell line as experiment subject as it demonstrated the highest miR-182-5p level. HGC-27 cells were transfected with different vectors and the cell viability, mitosis, invasion, and migration ability were measured through MTT assay, flow cytometry (FCM) analysis, Transwell assay, and wound healing assay. In comparison with the normal tissues, miR-182-5p is expressed at a higher level in gastric cancer (GC) tissues, while RAB27A is expressed at a lower level in cancerous tissues. The down-regulation of miR-182-5p and up-regulation of RAB27A can significantly decrease the viability, migration, invasion, and mitosis of HGC-27 cells. The target relationship between miR-182-5p and RAb27A was confirmed through a dual-luciferase reporter gene assay and Western blot assay. miR-182-5p enhances the viability, mitosis, migration, and invasion of human GC cells by down-regulating RAB27A.

Regulation of Gastric Carcinogenesis by InflammatoryCytokines.

Chronic inflammation caused by infection with Helicobacter pylori and autoimmune gastritis increases an individual’s risk of developing gastric cancer. More than 90% of gastric cancers are adenocarcinomas, which originate from epithelial cells in the chronically inflamed gastric mucosa. However, only a small subset of chronic gastritis patients develops gastric cancer, implying a role for genetic and environmental factors in cancer development. A number of DNA polymorphisms that increase gastric cancer risk have mapped to genes encoding cytokines. Many different cytokines secreted by immune cells and epithelial cells during chronic gastritis have been identified, but a better understanding of how cytokines regulate the severity of gastritis, epithelial cell changes, and neoplastic transformation is needed. This review summarizes studies in both human and mouse models, describing a number of different findings that implicate various cytokines in regulating the development of gastric cancer.

MiRNA-532-5p functions as an oncogenic microRNA in human gastric cancer by directly targeting RUNX3.

Accumulating data reveal that microRNAs are involved in gastric carcinogenesis. To date, no information was reported about the function and regulatory mechanism of miR-532-5p in human gastric cancer (GC). Thus, our study aims to determine the role and regulation of miR-532-5p in GC. Here, we found that transient and stable overexpression of miR-532-5p dramatically increased the potential of colony formation and migration of GC cells, decreased the percentage of cells in G1 phase and cell apoptosis in vitro, and increased the weight of mice lungs and number of lung xenografts in vivo. Gain-of-function, loss-of-function and luciferase activity assays demonstrated that miR-532-5p negatively regulated the expression of RUNX3 and its targets directly. We also found that miR-532-5p level was negatively correlated with RUNX3 gene expression in various GC cell lines. Our results indicate that miR-532-5p functions as an oncogenic miRNA by promoting cell growth, migration and invasion in human GC cells.

Interleukin-32 Increases Human Gastric Cancer Cell Invasion Associated with Tumor Progression and Metastasis

The proinflammatory cytokine interleukin-32 (IL-32) is a novel tumor marker highly expressed in various human carcinomas, including gastric cancer. However, its effects on prognosis of patients with gastric cancer and cancer metastasis are virtually unknown at present. The main aim of this study was to explore the clinical significance of IL-32 in gastric cancer and further elucidate the molecular mechanisms underlying IL-32-mediated migration and invasion. Gastric cancer cells with ectopic expression or silencing of IL-32 were examined to identify downstream molecules and establish their effects on cell motility, invasion, and lung metastasis in vivo. IL-32 was significantly upregulated in gastric cancer and positively correlated with aggressiveness of cancer and poor prognosis. Ectopic expression of IL-32 induced elongated morphology and increased cell migration and invasion via induction of IL-8, VEGF, matrix metalloproteinase 2 (MMP2), and MMP9 expression via phosphor-AKT/phospho-glycogen synthase kinase 3β/active β-catenin as well as hypoxia-inducible factor 1α (HIF-1α) signaling pathways. Conversely, depletion of IL-32 in gastric cancer cells reversed these effects and decreased lung colonization in vivo. Examination of gene expression datasets in oncomine and staining of gastric cancer specimens demonstrated the clinical significance of IL-32 and its downstream molecules by providing information on their coexpression patterns. IL-32 contributes to gastric cancer progression by increasing the metastatic potential resulting from AKT, β-catenin, and HIF-1α activation. Our results clearly suggest that IL-32 is an important mediator for gastric cancer metastasis and independent prognostic predictor of gastric cancer.

MiR-1303 Targets Claudin-18 Gene to Modulate Proliferation and Invasion of Gastric Cancer Cells

MicroRNAs have emerged as important gene regulators and are recognized as important molecules in carcinogenesis. However, the effects of microRNA-1303 (miR-1303) on gastric cancer (GC) cells and the upstream regulation of GC-associated claudin-18 gene (CLDN18) remain unclear. miR-1303 may be involved in the tumorigenesis of GC by targeting CLDN18. The purpose of this study was to explore the effect of miR-1303 targeting of CLDN18 on the proliferation, migration and invasion of human GC cells. The expression of miR-1303 and claudin-18 in GC tissues and gastric cancer cell lines were detected by qRT-PCR and western blotting, respectively. CCK8 and colony formation assays were performed to study the influence of miR-1303 on the proliferation of the GC cell lines. Transwell and wound-healing assays were carried out to investigate the effect of miR-1303 on the invasion and migration of GC cell lines. Luciferase reporter assays, restore assays and western blotting were used to demonstrate whether CLDN18 is a direct target of miR-1303. miR-1303 was significantly overexpressed whereas claudin-18 was downregulated in GC tissues and cell lines, which was significantly associated with tumor size, location invasion, histologic type and tumor-node-metastasis stage. Cell proliferation rates were reduced, and cell invasion and migratory ability was significantly restricted in miR-1303 inhibitor-transfected groups. miR-1303 could bind to the putative binding sites in CLDN18 mRNA 3'-UTR and visibly lower the expression of claudin-18. The introduction of claudin-18 without 3'-UTR restored the miR-1303 promoting migration function. Downregulation of miR-1303 can inhibit proliferation, migration and invasion of GC cells by targeting CLDN18.

Inhibition of AGS human gastric cancer cell invasion and proliferation by Capsosiphon fulvescens glycoprotein

Seaweeds are increasingly being used as foodstuffs and therapeutics. Capsosiphon fulvescens (C. fulvescens) is a green sea alga which has demonstrated anti-tumor activity in various cancer cell lines. In cancer cells, homeostasis is not maintained, enabling mutations to develop and growth to continue unchecked. Overexpression of matrix metalloproteinase (MMP) and tight junction (TJ) proteins is important for cancer cell proliferation, invasion and metastasis. In addition, these proteins are closely associated with cell membrane permeability. In the current study, C. fulvescens glycoprotein (Cf-GP) was found to inhibit TJ proteins and invasion of AGS human gastric cancer cells. Cf-GP-mediated inhibition of cell proliferation and invasion was confirmed, as well as changes in TJ protein levels. In addition, MMP-2 and −9 activities were inhibited, as indicated by increased transepithelial electrical resistance. Inhibition of MMP protein expression was also found to correlate with tissue inhibitor of metalloproteinase 1 and Cf-GP treatment, as revealed by western blot analysis and RT-PCR. In conclusion, these results indicate that Cf-GP inhibits cancer cell invasion and therefore demonstrates a potential therapeutic strategy to decrease cancer metastasis.

Icariin exterts negative effects on human gastric cancer cell invasion and migration by vasodilator-stimulated phosphoprotein via Rac1 pathway

Cellular movement is mainly orchestrated by actin-dependent cytoskeleton in which Rho GTPase Rac1 or vasodilator-stimulated phosphoprotein (VASP) closely collaborates. In the present in vitro study, we investigated the inhibitory effect and underlying molecular mechanism of icariin, a pure extract of the traditional Chinese medicine Herba epimedii, on the invasive and migration properties of human gastric cancer cell line BGC-823. At 50% growth-inhibiting concentration, icariin significantly suppressed tumor cells migration and invasion, which were traceable to down-regulation of Rac1 and VASP. Together with icariin, the selected siRNA targeting Rac1 or VASP reinforced these inhibitory effects. Rac1-siRNA-dependent down-regulation of Rac1 led to a large drop in VASP expression, whereas VASP-siRNA led to a slight fall in Rac1 expression, implying that the amount of Rac1 may influence VASP expression level. Moreover, transfection with Rac1 plasmids pcDNA3-EGFP-Rac1-Q61L led to the enhancement in expression level of both Rac1 and VASP. These results indicate that icariin exerts negative effects on tumor cell invasion and migration via the Rac1-dependent VASP pathway and may be a potential anti-cancer drug.

Protein Kinase C: A Novel Target for Inhibiting Gastric Cancer Cell Invasion

Gastric adenocarcinoma is a common neoplasm worldwide. Patients with completely resected disease often have locoregional recurrence, and adjuvant chemotherapy has failed to reduce the common occurrence of metastases. Protein kinase C (PKC) is thought to be important in tumor cell invasion, but its relationship to gastric cancer cell invasion, and thus metastases, remains unexplored. We recently identified and established invasive and noninvasive human gastric adenocarcinoma cell lines, which can now be used to test agents for inhibition of tumor cell invasion by inhibition of PKC activity. The objectives were (a) to test threo-dihydrosphingosine (SPC100221), a specific inhibitor of PKC at its regulatory site, and staurosporine, a potent but nonspecific inhibitor of PKC at its catalytic site, for their effects on gastric cancer cell invasion in vitro and (b) to determine whether the expression of PKC isoforms can distinguish invasive from noninvasive gastric cancer cells. Gastric cancer cell invasion through Matrigel-coated Nuclepore filters in the Boyden chamber assay was analyzed in the presence of graded concentrations of SPC100221 and staurosporine. The invasive SK-GT-1 and SK-GT-5 cell lines and the noninvasive SK-GT-2 and SK-GT-4 cell lines were used. PKC isoform expression was determined by reverse transcription of messenger RNAs to complementary DNA and subsequent amplification by the polymerase chain reaction. The effects of staurosporine and SPC100221 on tumor cell invasion were tested at drug concentrations that did not inhibit cell proliferation, as evidenced by [3H]thymidine uptake. Staurosporine and SPC100221 at subtoxic doses inhibited human gastric cancer cell invasion by 50% at 5 x 10(-9) M and 2 x 10(-7) M, respectively. The expression of PKC beta was observed in the invasive but not the noninvasive gastric cancer cells. Both types of cells, however, expressed the PKC alpha and PKC gamma isoforms. Gastric cancer cell invasion can be inhibited by PKC inhibitors, and expression of PKC beta may be a marker of invasiveness in gastric cancer. PKC appears to represent a new target for inhibition of gastric cancer cell invasion, and SPC100221, in view of its PKC specificity, may provide a model for future drug development in this area. Moreover, PKC beta may have a fundamental role in the development of invasive potential in gastric cancer.