Water-soluble Yb3+, Er3+ codoped NaYF4 nanoparticles induced SGC-7901 cell apoptosis through mitochondrial dysfunction and ROS-mediated ER stress.

BACKGROUND: Nanoparticles are potential luminescent probes; among them, upconversion nanoparticles (UCNP) are currently being developed as fluorescent probes for biomedical applications. However, the molecular mechanisms of UCNP in human gastric cell lines remain poorly understood. Here, we aimed to examine UCNP cytotoxicity to SGC-7901 cells and explore its underlying mechanisms. METHODS: The effects of 50-400 µg/mL UCNP on human gastric adenocarcinoma (SGC-7901) cells were investigated. Flow cytometry was used to evaluate reactive oxygen species (ROS), mitochondrial membrane potential (ΔΨm), intracellular Ca2+ levels, and apoptosis. Activated caspase-3 and nine activities were measured; meanwhile, cytochrome C (Cyt C) in the cytosol and B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X protein (Bax), protein kinase B (Akt), phosphorylated-Akt (p-Akt), 78 kDa glucose-regulated protein (GRP78), 94 kDa glucose-regulated protein (GRP94), calpain-1, and calpain-2 protein levels were also detected. RESULTS: UCNP inhibited the viability of SGC-7901 cells in a concentration- and time-dependent manner and increased the proportion of cell apoptosis. Exposure to UCNP enhanced the ratio of Bax/Bcl-2, elevated the level of ROS, decreased ΔΨm, increased intracellular Ca2+ and Cyt C protein levels, decreased the levels of phosphorylated Akt, increased the activity of caspase-3 and caspase-9, and upregulated the protein expression of GRP-78, GRP-94, calpain-1 and calpain-2 in SGC-7901 cells. CONCLUSION: UCNP induced SGC-7901 cell apoptosis by promoting mitochondrial dysfunction and ROS-mediated endoplasmic reticulum (ER) stress, initiating the caspase-9/caspase-3 cascade.

[Effects of Betulinic acid on apoptosis in human gastric cancer SGC-7901 cells].

Objective: To investigate the effects of betulinic acid on apoptosis of human gastric cancer SGC-7901 cells. Methods: The human gastric cancer SGC-7901cells were divided in to 4 groups, and each group was set with 3 replicates. The SGC-7901cells in control group were not treated with betulinic acid; the other 3 experimental groups were treated with betulinic acid at the concentrations of 10, 20 and 30 mg/L, respectively; each group was incubated in a 5% carbon dioxide incubator for 48 h. Laser confocal microscope was used to observe morphological changes of SGC-7901 cells; Flow cytometry was applied to determine apoptosis rate and mitochondrial membrane potential. The mRNA and protein levels of Bcl-2, Bax and Caspase-3 were also detected by qRT-PCR and western blot respectively. Results: Compared with the control group, SGC-7901 cells in the treated group at final concentrations of 10, 20 and 30 mg/L shrinked, appeared apoptosis body along with nuclear splitting. The percentage of cells in early and advanced period of apoptosis were markedly increased (P＜0.05 or P＜0.01), mitochondrial membrane potential was obviously reduced (P＜0.05 or P＜0.01). qRT-PCR and western blot analysis showed that the mRNA and protein expressions of Bax and Caspase-3 were increased significantly (P＜0.01), while the expressions of Bcl-2 were decreased significantly (P＜0.01). Conclusion: Within a certain range of concentrations, betulinic acid induces cell apoptosis by regulating the expression of Bcl-2, Bax and Caspase-3 in human gastric cancer.

Screening and preliminary analysis of differentially expressed miRNAs in gastric cancer cell-derived exosomes induced by Helicobacter pylori / 中华微生物学和免疫学杂志

Objective:To investigate the differentially expressed microRNAs (miRNAs) in human gastric carcinoma SGC-7901 cell-derived exosomes induced by Helicobacter pylori ( H. pylori), providing new clues for further elucidating the carcinogenic mechanism of H. pylori. Methods:Ultracentrifugation and exosome extraction kit were used to extract the exosomes released by the H. pylori-stimulated and negative control group, and transmission electron microscope(TEM), nanoparticle tracking analysis(NTA) and Western blot experiments were employed to identify exosomes. Then, exosomes were labeled with the fluorescent dye PKH67 and co-cultured with THP-1-derived macrophages. The internalization of exosomes by macrophages was observed by laser confocal fluorescent microscopy. Additionally, miRNA microarray chips were performed to detect the differentially expressed miRNAs of exosomes from the two groups of cells. Real-time fluorescence quantitative PCR (qRT-PCR) was used to verify the expression of four differentially expressed miRNAs. Furthermore, the target genes and their functions as well as the possible signal pathways involved of partial differentially expressed miRNAs were predicted and analyzed by bioinformatics software. Differentially expressed miR-382-5p was labeled by Cy3 to observe whether it could be transferred to macrophages through exosomes. The expression of phenotype molecule CD206 and the cytokines TNF-α, IL-6 and IL-10 in miR-382-5p mimic-transfected macrophages were analyzed by qRT-PCR and ELISA, and the proportion of cells expressing CD206 and HLA-DR was analyzed by flow cytometry. Results:The extracted exosomes were consistent with exosome morphology and highly expressed the surface marker proteins CD9, CD63 and TSG101. After co-culturing with THP-1 derived macrophages for 12 h, the exosomes could be internalized by macrophages. Compared with the control group, there were 130 up-regulated miRNAs and 111 down-regulated miRNAs in the H. pylori-stimulated group. Bioinformatic analysis showed that the potential target genes of partial differentially expressed miRNAs were mainly involved in the regulation of PI3K-AKT, NF-κB, JAK-STAT, stem cell pluripotency and other inflammation and tumor-related pathways. miR-382-5p could be transferred to macrophages through exosomes, and induced the expression of M2-type phenotype molecule CD206 and cytokines IL-10 in macrophages, while inhibited the expression of TNF-α and IL-6 and increased the proportion of CD206 high HLA-DR low cells. Conclusions:H. pylori treatment caused a significant change in the expression level of exosome miRNAs in SGC-7901 cells. Bioinformatics analysis demonstrated that the prospective targets of these differentially expressed miRNAs might play an important role in the regulation of inflammation and tumor-related signaling pathways. miR-382-5p might induce the M2-type polarization of macrophages.

Gamma linolenic acid suppresses hypoxia-induced gastric cancer cell growth and epithelial-mesenchymal transition by inhibiting the Wnt/b-catenin signaling pathway.

INTRODUCTION: Gastric cancer is one of the most common malignancies in China and the fifth most common cancer in the world. Gamma linolenic acid (GLA) was reported to have anti-inflammatory and anti-cancer effects. The purpose of this research was to investigate the effect and mechanism of GLA on gastric cancer cell growth under hypoxic conditions. MATERIAL AND METHODS: The hypoxia models of SGC-7901 and MGC-803 cells were established, and then were exposed to different concentrations of 50, 100 or 200 µM GLA. MTT assay, colony formation assay, wound healing assay and transwell assay were used to investigate the effects of GLA treatment on gastric cancer cell growth under hypoxia (1% O2). The expression of apoptosis- and epithelial-mesenchymal transition (EMT)-related proteins was detected by qPCR and western blot. RESULTS: GLA treatment significantly decreased viability and inhibited colony formation (p < 0.05, p < 0.01) of SGC-7901 and MGC-803 cells under hypoxia. Western blotting analysis showed that GLA treatment decreased the expression of proliferating cell nuclear antigen (PCNA), microchromosome maintenance complex component 2 (MCM-2) and anti-apoptotic protein Bcl-2, while increased the expression of pro-apoptotic proteins (Bax and Cleaved Caspase-3) (p < 0.05 and p < 0.01). In addition, Wound healing analysis and Transwell assays showed that GLA treatment inhibited the migration and invasion of SGC-7901 and MGC-803 cells in a dose-dependent manner (p < 0.01). Western blotting analysis showed that GLA treatment increased the expression of epithelial marker proteins (g-catenin and E-cadherin), while decreased the expression of stromal and extracellular matrix marker proteins (fibronectin, Snail and b-catenin) (p < 0.01). Further analyses showed that GLA treatment decreased the expression of b-catenin in Wnt/b-catenin pathway (p < 0.01). Moreover, exogenous Wnt3a reversed the inhibitory effect of GLA on b-catenin expression, and further reversed the inhibitory effect of GLA on gastric cancer cell growth and EMT markers (p < 0.05, p < 0.01). CONCLUSION: These findings suggest that GLA should be tested in animal models and in clinical studies as a potentially effective bioactive phytochemical substance for the treatment of gastric cancer.

miR-454 promotes survival and induces oxaliplatin resistance in gastric carcinoma cells by targeting CYLD.

MicroRNA-454 (miR-454), is involved in the progression of various types of cancers. The present study aimed to evaluate the effect of miR-454 on the progression of gastric cancer. SGC-7901 cells overexpressing or silencing miR454 were constructed via transfection and the survival rate of the cells was determined. The relationship between miR-454 and cylindromatosis (CYLD) was explored and the influence of miR-454 on oxaliplatin resistance was investigated in SGC-7901 cells. It was determined that overexpression of miR-454 increased the number of colonies and reduced apoptosis rate of SGC-7901 cells. The CYLD gene was identified as a direct target of miR-454. miR-454 overexpression downregulated the expression of CYLD, leading to an increase in SGC-7901 cell proliferation. Finally, miR-454 was also demonstrated to induce resistance to oxaliplatin in gastric cancer cells. In conclusion, the present in vitro findings suggested that miR-454 might be a novel therapeutic target for gastric cancer.

[Effect of betulinic acid on proliferation of human gastric cancer SGC-7901 cells].

Objective: Human gastric cancer SGC-7901 cells were treated with betulinic acid(BA)at the concentrations of 0, 10, 20, and 30 µg/ml, and treated with conventional chemotherapeutic drug 5-Fu as a positive control to explore its effect on cell proliferation. Trypan blue and GIEMSA staining method were used to investigate the effect of BA on cell growth inhibition and clone formation. EdU method and flow cytometry were used to explore the proliferation and cell cycle of SGC-7901 cells after treated with BA, respectively. qRT-PCR and Western blot were also applied to determine the mRNA and protein levels of cyclin D1 and cyclin B1. Results: The cell growth inhibition rate was increased after treated with different concentrations of BA in SGC-7901 cells(P＜0.05). After treated for 48 h, BA decreased the clone information and cell proliferation of SGC-7901 cells markedly in dose-and time-dependent manners (P＜0.01). Flow cytometry analysis showed that BA obviously increased the proportion of SGC-7901 cells in G1 phase but decreased the proportion of those in S phase. qRT-PCR and Western blot analysis showed that the mRNA and protein levels of cyclin D1 and cyclin B1 were significantly downregulated by BA at different concentrations(P＜0.01). Compared with the 5-Fu control group, when the concentration of BA was 20 µg/ml and 30 µg/ml, the cell proliferation ability was significantly decreased, the cell cycle was inhibited, and the expression of cyclin was reduced (all P＜0.05). Conclusion: The betulinic acid regulates the proliferation of SGC-7901 cells by inhibiting the expressions of cyclin D1 and cyclin B1, which leads to cell cycle arrest and proliferative inhibition.

3-(3-Methoxyphenyl)-6-(3-amino-4-methoxyphenyl)-7H-[1,2,4] triazolo [3,4-b][1,3,4] thiadiazine, a novel tubulin inhibitor, evokes G2/M cell cycle arrest and apoptosis in SGC-7901 and HeLa cells.

Gastric cancer and cervical cancer are two major malignant tumors that threaten human health. The novel chemotherapeutic drugs are needed urgently to treat gastric cancer and cervical cancer with high anticancer activity and metabolic stability. Previously we have reported the synthesis, characterization and identification of a novel combretastatin A-4 analog, 3-(3-methoxyphenyl)-6-(3-amino-4- methoxyphenyl) -7H-[1,2,4]triazolo[3,4-b][1,3,4] thiadiazine (XSD-7). In this study, we sought to investigate its anticancer mechanisms in a human gastric cancer cell line (SGC-7901 cells) and human cervical carcinoma cell line (HeLa cells). The 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay showed that XSD-7 induced cytotoxicity in SGC-7901 and HeLa cells with inhibitory concentration 50 values of 0.11 ± 0.03 and 0.12 ± 0.05 µM, respectively. Immunofluorescence studies proved that XSD-7 inhibited microtubule polymerization during cell division in SGC-7901 and HeLa cells. Then, these cells were arrested at G2/M cell cycle and subsequently progressed into apoptosis. In further study, mitochondrial membrane potential analysis and Western blot analysis demonstrated that XSD-7 treatment-induced SGC-7901 cell apoptosis via both the mitochondria-mediated pathway and the death receptor-mediated pathway. In contrast, XSD-7 induced apoptosis in HeLa cells mainly via the mitochondria-mediated pathway. Hence, our data indicate that XSD-7 exerted antiproliferative activity by disrupting microtubule dynamics, leading to cell cycle arrest, and eventually inducing cell apoptosis. XSD-7 with novel structure has the potential to be developed for therapeutic treatment of gastric cancer and cervical cancer.

Gambogic acid suppresses invasion in human gastric carcinoma SGC-7901 cells by modulating inhibitor of nuclear factor kappa-B kinase α/p65 signaling pathway in vitro / 解剖学报

Objective To investigate the effect of gambogic acid (GA) on invasion in human gastric carcinoma SGC-7901 cells and its possible mechanism. Methods Cell counting kit-8(CCK-8) assay was performed to detect the effects of GA, inhibitor of nuclear factor kappa-B kinase( IKK) 16 and 5-fluorouracil (5-FU) on cell activity of GES-1 and SGC-7901 cells. Cell invasion was assessed with Transwell invasion assay. Western blotting was used to analyze the protein levels of vimentin, matrix metalloproteinase 2 ( MMP-2) and MMP-9 and protein phosphorylation of IKKα and p65. Results The cell activity was significantly decreased in SGC-7901 cells treated with GA in a dose-dependent manner with a half inhibiton concentration(IC50) value of 1. 89 μmol/L. But GA had no significant influence on cell viability of GES-1 cells. Meanwhile, 5-FU reduced the cell activity of GES-1 and SGC-7901 cells with IC50values of 7.36 μmol/L and 199.57 μmol/L respectively. Low-dose GA and IKK 16 impaired separately the ability of invasion in SGC-7901 cells, and down-regulated the protein levels of MMP-2, MMP-9 and vimentin, and inhibited phosphorylation of IKKot and p65, while a stronger inhibition was showed when the combination of GA and IKK16 was used. Conclusion Low-dose GA might inhibit invasion of SGC-7901 cells via IKKot/p65 signaling pathway.

Crebanine N-oxide, a natural aporphine alkaloid isolated from Stephania hainanensis, induces apoptosis and autophagy in human gastric cancer SGC-7901 cells

Objective: To investigate the cytotoxic effects and the potential mechanisms of crebanine N-oxide in SGC-7901 gastric adenocarcinoma cells. Methods: The cytotoxicity of crebanine N-oxide was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay and cellular morphology was observed under a microscope. Cell apoptosis was determined by flow cytometry using propidium iodide staining. The expression levels of apoptotic-related proteins, cleaved caspase-3, cytochrome C, p53 and Bax, and autophagyrelated proteins p62, beclin1 and LC3 were detected by Western blotting assays. Results: Crebanine N-oxide treatment significantly inhibited the proliferation of SGC-7901 cells in a dose-dependent and timedependent manner via induction of G2-phase cell cycle arrest, apoptosis, and autophagy in SGC-7901 cells. Conclusions: Crebanine N-oxide could inhibit the growth of gastric cancer cells by promoting apoptosis and autophagy and could be used as a potential agent for treating gastric cancer.

Crebanine N-oxide, a natural aporphine alkaloid isolated from Stephania hainanensis, induces apoptosis and autophagy in human gastric cancer SGC-7901 cells

Objective: To investigate the cytotoxic effects and the potential mechanisms of crebanine N-oxide in SGC-7901 gastric adenocarcinoma cells. Methods: The cytotoxicity of crebanine N-oxide was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay and cellular morphology was observed under a microscope. Cell apoptosis was determined by flow cytometry using propidium iodide staining. The expression levels of apoptotic-related proteins, cleaved caspase-3, cytochrome C, p53 and Bax, and autophagy-related proteins p62, beclin1 and LC3 were detected by Western blotting assays. Results: Crebanine N-oxide treatment significantly inhibited the proliferation of SGC-7901 cells in a dose-dependent and time-dependent manner via induction of G

[Mechanism of ß-carboline alkaloids inhibiting migration and invasion of SGC-7901 cells].

To explore the mechanism of ß-carboline alkaloids inhibiting the migration and invasion of SGC-7901 cells and its correlation with FAK gene expression,CCK-8 method was used to determine the inhibitory rate of ß-carboline alkaloids on the proliferation of gastric cancer SGC-7901 cells under different concentrations.The effect of ß-carboline alkaloids on the migration and invasion of SGC-7901 cells was used by Transwell compartment.Detection of mRNA and protein expression of FAK genes were used by qRT-PCR and Western blot.Then si-FAK-1051 recombinant plasmid was transfected into SGC-7901 cells.FAK gene silencing effect was identified by qRT-PCR and Western blot technique again.Finally,the effects of FAK gene silencing on proliferation and migration of gastric cancer SGC-7901 cells were detected by CCK-8 kit and Transwell chamber assay respectively.With the increase of the concentration ofß-carboline alkaloids,the inhibitory rate of SGC-7901 cells in human gastric cancer cells increased gradually,with IC5013.364 mg·L-1.The number of SGC-7901 cells of Transwell compartment in the positive experimental group(5-FU,5 mg·L-1) and the ß-carboline alkaloids group decreased significantly(P<0.01) and the number of SGC-7901 cells in the ß-carboline alkaloids group was significantly lower than that in the positive experimental group(P<0.01).Compared with the blank control group,the mRNA and protein expression level of FAK genes in the positive experimental group was significantly lower than that in the experimental group of ß-carboline alkaloids(P<0.05).After transfection of si-FAK-1051 into gastric cancer SGC-7901 cells,the expression of mRNA and protein of FAK gene was significantly down regulated(P<0.05).SGC-7901 cell proliferation and cell migration ability also decreased significantly(P<0.05).ß-carboline alkaloids are more effective than 5-FU in inhibiting migration and invasion of gastric cancer SGC-7901 cells,and the mechanism may be related to the inhibition of mRNA and protein expression of FAK gene by ß-carboline alkaloids.

Wogonin affects proliferation and the energy metabolism of SGC-7901 and A549 cells.

Many studies have focused on the identification of therapeutic targets for the treatment of certain types of cancer. Wogonin is a natural flavonoid compound that exhibits a potent anti-cancer effect. The underlying mechanism of wogonin may therefore reveal an effective way to identify novel therapeutic targets. In the current study, growth curves and MTT assays were performed to determine the effects of wogonin in human gastric cancer cells (SGC-7901) and human lung adenocarcinoma cells (A549), respectively. Changes in morphology were observed using hematoxylin and eosin (H&E) staining. The activities of key enzymes in the glycolysis and tricarboxylic acid cycle were measured using spectrophotometry. Western blot analysis was performed to determine the expression levels of hypoxia inducible factor-1α (HIF-1α) and monocarboxylate transporter-4 (MCT-4). Wogonin inhibited cell proliferation in a time- and dose-dependent manner in SGC-7901 and A549 cells. H&E staining suggested that wogonin induced cell morphology changes. In SGC-7901 cells, lactate dehydrogenase (LDH) and succinate dehydrogenase (SDH) activities and adenosine triphosphate (ATP) generation were decreased significantly by wogonin treatment compared with the untreated control. In A549 cells, wogonin significantly reduced LDH activity, but exhibited no significant effects on kinase activities or ATP generation. Furthermore, wogonin significantly decreased HIF-1α and MCT-4 protein expression in SGC-7901 cells, but not in A549 cells. The results demonstrated that wogonin inhibited the energy metabolism, cell proliferation and angiogenesis in SGC-7901 and A549 cells by negatively regulating HIF-1α and MCT-4 expression. The differential regulatory roles of wogonin in metabolism-associated enzymes in human gastric cancer and lung adenocarcinoma cells indicated its various antitumor mechanisms. The different metabolic regulatory mechanisms exhibited by wogonin in different tumor tissues should therefore be considered for antitumor therapy.

Ethanolic extract of Cordyceps cicadae exerts antitumor effect on human gastric cancer SGC-7901 cells by inducing apoptosis, cell cycle arrest and endoplasmic reticulum stress.

ETHNOPHARMACOLOGICAL RELEVANCE: Cordyceps cicadae (Miq.) Massee is a traditional Chinese medicine that has been used for approximately 1600 years in China. C. cicadae, a member of the Cordyceps genus, exerts a therapeutic effect on many diseases, such as cancer. OBJECTIVE: This study aimed to evaluate the antineoplasmic activity of C. cicadae and to identify its molecular mechanism of cell death. MATERIALS AND METHODS: The toxicity of the ethanolic extract of C. cicadae (EEC) against different cancer cell lines was determined through MTT assay. Human gastric cancer SGC-7901 cells were treated with EEC for 48 h. Cell morphology was examined by using an Olympus phase-contrast microscope. The cell apoptosis was quantified through Annexin V-FITC/PI staining. Cells were stained with PI and then subjected to flow cytometry for the investigation of cell cycle status. Cells were subjected to mitochondrial membrane potential (MMP) assay after incubation with JC-1 probes and to intracellular Ca2+ measurement through flow cytometry after incubation with Fluo-3 AM fluorescent probes. Western blot analysis was conducted to quantify the expression of proteins related to apoptosis, cell cycle and endoplasmic reticulum stress. High-performance liquid chromatography (HPLC) analysis was performed to analyse the biological activity components of EEC. RESULTS: EEC suppressed the proliferation of SGC-7901 cells and induced the development of abnormal morphological features in a dose-dependent manner. Flow cytometry results indicated that EEC treatment caused cell apoptosis and arrested the cell cycle in the S phase. In addition, EEC treatment triggered MMP depolarization and Ca2+ overloading in the cytosol of SGC-7901 cells. Western blot analysis demonstrated that EEC increased Bax, AIF, caspase-8, caspase-6 and caspase-3 activities and decreased Bcl-2 activity. The release of cytochrome c from mitochondria was associated with mitochondrial dysfunction, which was caused by the activation of the cell surface receptor Fas and the cleavage of PARP. EEC-induced S phase arrest was associated with the up-regulation of E2F1, cyclin A2, cyclin E and p53 expression levels and the down-regulation of CDK2 expression. In addition, EEC increased the expression of endoplasmic reticulum stress-related proteins, such as calpain-1, caspase-12 and caspase-9. HPLC assay results suggested that EEC contained adenine, uridine, adenosine and N6-(2-Hydroxyethyl)-adenosine. CONCLUSION: EEC inhibited the proliferation of SGC-7901 cells by inducing caspase-dependent apoptosis, arresting the cell cycle in the S phase and increasing endoplasmic reticulum stress. This study revealed that C. cicadae is a potential natural source of anticancer drugs.

HOXB9 inhibits proliferation in gastric carcinoma cells via suppression of phosphorylated-Akt and NF-κB-dependent Snail expression.

BACKGROUND: HOXB9 is a homeobox transcription factor which plays an important role in carcinoma development. This protein has been shown to inhibit cancer cell proliferation. However, the mechanisms that underpin HOXB9-mediated inhibition of cellular proliferation remain to be elucidated. METHODS: In this study, two gastric cancer cell lines, SGC7901 and MKN45, were transfected with plasmids pLVX-HOXB9 and shHOXB9. These transfections resulted in the over-expression of the HOXB9 gene in the SGC7901/HOXB9 cells and knockdown of the HOXB9 gene in the MKN45/shHOXB9 cells. RESULTS: Over-expression of the HOXB9 gene in the SGC7901/HOXB9 cells caused an increase in the apoptotic rate and a concomitant reduction in metastatic ability compared with the knocked-down MKN45/shHOXB9 cells. Moreover, a reduction in the expression of the phosphorylated-Akt protein was observed in the SGC7901/HOXB9 cells, while an increase in expression of the same protein was observed in the MKN45/shHOXB9 cells. We also observed that HOXB9 mediated a reduction in both NF-κB and N-cadherin and Snail protein expression. Conversely, HOXB9 caused an increase in the expression of E-cadherin. CONCLUSIONS: In summary, this study reports that HOXB9 can suppress both phosphorylated-Akt expression and NF-κB activity. The latter phenomenon affects Snail protein expression and the inhibition of gastric carcinoma proliferation.

Inhibitory effect of lumbrokinase on proliferation and induction on apoptosis of gastric cancer sgc7901 cells / 吉林大学学报(医学版)

Objective: To investigate the regulatory effect of lumbrukinase CI.RK) on the gastric cancer SGC7901 Cells, and to clarify its mechanism Methods: The SGC7901 cells in the logarithmic growth phase were selected and divided into control group and 2, 4 , 8 U • ml. I.RK groups. MTT assay was used to detect the inhibitory rates of proliferation of SGC7901 cells in various groups in vitro at different time (24, 48 and 72 h). Cell scratch assay was used to detect the migration abilities of the SGC7901 cells in vitro in various groups. Flow cytometry was used to determine the apoptotic rates of SGC7901 cells and the pencentages of cells at different cell cycles in various groups. The expression levels of Bcl-2, Rax, and caspase-3 in the SGC790I cells in various groups were detected by Western blotting method. Results: The results of MTT assay showed that compared with control group, the inhibitory rates of SGC7901 cells in different doses of I.RK groups after treated for 24, 48 and 72 h were increased ( P<0.01). The cell scratch assay results showed that compared with control group, the migration distances of SGC790I cells in 4 and 8 U • mL"1 I.RK groups were increased significantly ( P

Inhibitory effect of lumbrokinase on proliferation and induction on apoptosis of gastric cancer SGC7901 cells / 吉林大学学报(医学版)

Objective:To investigate the regulatory effect of lumbrukinase (LBK) on the gastric cancer SGC7901cells, and to clarify its mechanism.Methods:The SGC7901cells in the logarithmic growth phase were selected and divided into control group and 2, 4, 8U·mL-1 LBK groups.MTT assay was used to detect the inhibitory rates of proliferation of SGC7901cells in various groups in vitro at different time (24, 48and 72h) .Cell scratch assay was used to detect the migration abilities of the SGC7901cells in vitro in various groups.Flow cytometry was used to determine the apoptotic rates of SGC7901cells and the pencentages of cells at different cell cycles in various groups.The expression levels of Bcl-2, Bax, and caspase-3in the SGC7901cells in various groups were detected by Western blotting method.Results:The results of MTT assay showed that compared with control group, the inhibitory rates of SGC7901cells in different doses of LBK groups after treated for 24, 48and 72hwere increased (P＜0.01) .The cell scratch assay results showed that compared with control group, the migration distances of SGC7901cells in4and 8U·mL-1 LBK groups were increased significantly (P＜0.01) .The flow cytometry results showed that compared with control group, the apoptotic rates of SGC7901cells in 4and 8U·mL-1 LBK groups were increased significantly (P＜0.01) ;the percentages of cells in G1and S phases were decreased (P＜0.01) ;the percentages of cells in G2phase were increased (P＜0.01) .The results of Western blotting method showed that compared with control group, the Bcl-2protein expression level in the SGC7901cells in 8U·mL-1 LBK group was decreased (P＜0.05) ;the Bax and caspase-3protein expression levels were increased (P＜0.05) .Conclusion:LBK can inhibit the proliferation and migration abilities of SGC7901cells in vitro and induce the apoptosis;its mechanism is achieved through the regulation of expression levels of Bcl-2, Bax, and caspase-3proteins.

Mechanism of β-carboline alkaloids inhibiting migration and invasion of SGC-7901 cells / 中国中药杂志

To explore the mechanism of β-carboline alkaloids inhibiting the migration and invasion of SGC-7901 cells and its correlation with FAK gene expression,CCK-8 method was used to determine the inhibitory rate of β-carboline alkaloids on the proliferation of gastric cancer SGC-7901 cells under different concentrations.The effect of β-carboline alkaloids on the migration and invasion of SGC-7901 cells was used by Transwell compartment.Detection of mRNA and protein expression of FAK genes were used by qRT-PCR and Western blot.Then si-FAK-1051 recombinant plasmid was transfected into SGC-7901 cells.FAK gene silencing effect was identified by qRT-PCR and Western blot technique again.Finally,the effects of FAK gene silencing on proliferation and migration of gastric cancer SGC-7901 cells were detected by CCK-8 kit and Transwell chamber assay respectively.With the increase of the concentration ofβ-carboline alkaloids,the inhibitory rate of SGC-7901 cells in human gastric cancer cells increased gradually,with IC5013.364 mg·L-1.The number of SGC-7901 cells of Transwell compartment in the positive experimental group(5-FU,5 mg·L-1) and the β-carboline alkaloids group decreased significantly(P<0.01) and the number of SGC-7901 cells in the β-carboline alkaloids group was significantly lower than that in the positive experimental group(P<0.01).Compared with the blank control group,the mRNA and protein expression level of FAK genes in the positive experimental group was significantly lower than that in the experimental group of β-carboline alkaloids(P<0.05).After transfection of si-FAK-1051 into gastric cancer SGC-7901 cells,the expression of mRNA and protein of FAK gene was significantly down regulated(P<0.05).SGC-7901 cell proliferation and cell migration ability also decreased significantly(P<0.05).β-carboline alkaloids are more effective than 5-FU in inhibiting migration and invasion of gastric cancer SGC-7901 cells,and the mechanism may be related to the inhibition of mRNA and protein expression of FAK gene by β-carboline alkaloids.

Resveratrol induces apoptosis in SGC-7901 gastric cancer cells.

The aim of the present study was to investigate the effect of resveratrol on apoptosis in SGC-7901 gastric cancer cells and its molecular mechanisms of action. Following resveratrol treatment, the inhibition rate of SGC-7901 cells was determined using an MTT assay. The morphological changes in apoptosis were observed by fluorescence microscopy based on acridine orange/ethidium bromide double staining. Furthermore, cell cycle and apoptosis were detected using flow cytometry, and the expression levels of nuclear factor κB (NF-κB) as well as apoptosis-associated proteins [B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), cleaved caspase-3 and cleaved caspase-8] were analyzed by western blotting. The results of the present study indicated that resveratrol was able to significantly inhibit the viability of SGC-7901 cells in a dose- and time-dependent manner. When treated with 200 µM resveratrol, the inhibition rate of SGC-7901 cells reached ~50%. In the presence of resveratrol, the proportion of apoptotic cells was also increased in a dose-dependent manner. Flow cytometry revealed that resveratrol induced S-phase arrest of SGC-7901 cells. When treated with 50, 200 and 400 µM resveratrol, the proportions of SGC-7901 cells in the S-phase were respectively increased to 33.8±2.42, 60.01±2.43 and 56.05±2.67%, compared with 25.62±3.29% for the control group cells in S-phase. Additionally, the levels of the pro-apoptotic proteins Bax, cleaved caspase-3 and cleaved caspase-8 were upregulated in a dose-dependent manner, whereas the level of the anti-apoptotic protein Bcl-2 was downregulated dose-dependently. Importantly, the activation of NF-κB (p65) was evidently decreased following treatment with resveratrol compared with in the control group. In conclusion, the results of the present study revealed that resveratrol was able to inhibit viability and induce apoptosis in SGC-7901 cells by suppressing NF-κB activation. Therefore, resveratrol may be considered as a potential drug candidate for the treatment of gastric cancer.

Xanthohumol induces apoptosis via caspase activation, regulation of Bcl-2, and inhibition of PI3K/Akt/mTOR-kinase in human gastric cancer cells.

We assessed the effect of xanthohumol (XN) on gastric cancer (GC) in vitro and in vivo. XN reduced the viability of SGC-7901, SNU216, and SNU668 cells, but not GES-1 non-tumorigenic human gastric epithelial cells. XN induced apoptosis in SGC-7901 cells in a concentration-dependent manner by enhancing the numbers of late and early apoptotic cells. XN also downregulated the anti-apoptotic proteins Bcl-XL and Bcl-2 and upregulated the pro-apoptotic proteins Bax, Bid, PARP, and caspase-3. XN induced phosphorylation of PI3K, Akt, and mTOR in SGC7901 cells. Also, XN reduced the tumour volume and weight by inhibiting the phosphorylation of Akt and mTOR. XN-treated tumours had significantly fewer proliferating cells and more apoptotic cells compared with the control. Our data indicate that XN induces apoptosis of human GC cells in vivo. Thus, XN may have potential as an anti-GC agent.

Autophagy plays a protective role against apoptosis induced by toxicarioside N via the Akt/mTOR pathway in human gastric cancer SGC-7901 cells.

Toxicarioside N (Tox N), a natural product extract from Antiaris toxicaria, has been reported to induce apoptosis in human gastric cancer cells. However, the mechanism and actual role of autophagy in Tox N-induced apoptosis of human gastric cancer cells remains poorly understood. In the current study, we demonstrated that Tox N could induce autophagy by inhibiting the Akt/mTOR signaling pathway in SGC-7901 cells. Moreover, we found that the inhibition of autophagy by 3-methyladenine, an autophagy inhibitor, enhanced Tox N-induced apoptotic cell death. However, the stimulation of autophagy by rapamycin, an autophagy activator, remarkably suppressed Tox N-induced apoptosis, suggesting that autophagy plays a protective role in Tox N-induced apoptosis. Thus, the results from this study suggested that Tox N combination with an autophagy inhibitor might be a promising strategy to enhance the anticancer activity of Tox N for the treatment of human gastric cancer.