Human Gastric Cancer SGC-7901 Cells Research Articles

Upregulation of periostin prevents P53-mediated apoptosis in SGC-7901 gastric cancer cells

Periostin is frequently upregulated in human cancers including gastric cancer and implicated in cancer cell proliferation, invasion, and epithelial-mesenchymal transition. This study was undertaken to investigate the effects of periostin overexpression on the chemosensitivity of gastric cancer cells. We constructed a stable cell line overexpressing periostin in SGC-7901 human gastric cancer cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay revealed that periostin had no influence on the proliferation of SGC-7901 cells. Compared to empty vector-transfected cells, overexpression of periostin rendered SGC-7901 cells more resistant to cisplatin or 5-fluorouracil (5-FU)-induced apoptosis, accompanying with less release of cytochrome c from mitochondria and diminished cleavage of caspase-3 and poly (ADP-ribose) polymerase. Periostin-overexpressing cells treated with cisplatin or 5-FU showed significantly (p<0.05) decreased expression of Bax and p53 proteins and increased expression of Bcl-2 protein, when compared to drug-treated mock counterparts. Restoration of p53 expression by delivering wild-type p53 gene resulted in a marked increase in drug-induced apoptosis in periostin-overexpressing SGC-7901 cells. Periostin overexpression elevated the phosphorylation of Akt. Pretreatment of periostin-overexpressing cells with an Akt inhibitor, MK-2206, partially rescued periostin-mediated inhibition of p53 expression and drug resistance. Taken together, our data indicate that periostin confers protection against cisplatin or 5-FU-induced apoptosis in SGC-7901 cells, likely through modulating the Akt/p53 pathway, and thus represents a potential therapeutic target in gastric cancer.

Effects of berberine on the proliferation and the protein expression of Bcl-2, Bax on human gastric carcinoma SGC-7901 cells

Berberine (BBR) is widely used to treat diarrhea and inflammation, and its antitumor activity has been vastly reported recently. However, its antitumor mechanism remained unclear. In the present study, the effects of Berberine on human gastric cancer SGC-7901 cells in vitroand its mechanism were investigated. Cisplatin (DDP) was used as positive control. The inhibition of drugs on SGC-7901 was evaluated with MTT assay. The level of Bcl-2 and Bax in the cells treated with different concentrations of Berberine were detected with Western blotting. MTT assay indicated significantly inhibitory effect of Berberine on SGC-7901 cells in a dose- and time-dependent manner. Annexin V-FITC and propidium iodide (PI) staining showed that BBR had a positive effect on apoptosis of SGC-7901 cells. After 2.5 μg/ml of BBR treating SGC-7901 cells for 48 h, the cells apoptosis rate (24.32 ± 0.71%) had statistical significance as compared with the negative group (2.77 ± 0.39%) (P = 0.000). Berberine up-regulated the levels of Bax, but down-regulated the level of Bcl-2 protein by Western blot. These results indicated that BBR exhibited potential anticancer activity against human gastric cancer SGC-7901 cells through induction of apoptosis and the imbalance of the ratio of Bcl-2/Bax. Key words: Human gastric carcinoma SGC-7901, berberine, Bcl-2, Bax.

Biological role of β-arrestin1 in human gastric cancer BGC-823 cells

Objective To investigate the effects of β-arrestinl on proliferation, migration, invasion and apoptosis of human gastric cancer BGC-823 cell line. Methods The expression of β- arrestinl in human gastric epithelial cell line GES, human gastric cancer cell line BGC-823, MKN-28 and SGC-7901 was detected by realtime-polymerase chain reaction （PCR） and Western blot. The stable β-arrestinl and negative control interfered BGC-823 cell line were established by RNA interference technology. The cell proliferation, migration, invasion and cell apoptosis of β-arrestinl stable interfered BGC-823 cell line was examined by cell counting, scratch test, Transwell chamber test and flow cytometry assays. The data were analyzed by t test. Results The expression of β- arrestinl in cell line GES, MKN-28, SGC-7901 and BGC-823 was 0. 001 ± 0. 001, 0. 002±0. 000, 0. 003± 0. 002 and 0. 005 ± 0. 000 respectively. The inhibition ratio of proliferation in β-arrestinl interfered BGC-823 cells and negative control cells were -30.2% and 100.0%. The invasion ability was also inhibited, the number of migratory cells was 126. 25±3.24 and 213. 50±6.27 （t=0. 000, P〈0.01）, and the apoptosis rate was （41. 350±1. 053）% and （11. 497±0. 589）% （t=0. 015, P〈0.05）. Conclusions β-arrestinl is highly expressed in gastric carcinoma, and the expression increased along with the malignancy degree. The cell proliferation, migration and invasion is inhibited by interference of β-arrestinl in BGC-823 cells, while the cell apoptosis is promoted. Key words: β-arrestinl; Stomach neoplasms; RNA interference; Tumor cells, cultured

Antitumor activity of Xiaoaiping injection on human gastric cancer SGC-7901 cells

Xiaoaiping, extracted from Marsdenia tenacissima (Asclepiadaceae), is a Chinese medicine used to treat cough and asthma. Previous studies have shown that its active ingredients possess anti-inflammatory and anticancer effects. The aim of this study was to investigate the antitumor activities of Xiaoaiping through apoptosis induction in human gastric cancer SGC-7901 cells. The MTT assay was used to assess the cell growth and cell viability. SGC-7901 cells were treated with Xiaoaiping injection [(20–40) mg·mL−1] for 24 and 48 h. The apoptotic cells and the cell cycle distribution were analyzed by flow cytometry. The in vivo activity of Xiaoaiping was determined by the growth inhibition of the established tumor xenografts in nude mice. Caspase-3 activity, Bax and Bcl-2 proteins in tumor tissue were measured by immunohistochemistry and apoptosis was assayed by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) method. Xiaoaiping inhibited SGC-7901 cell growth in a time and dose dependent-manner and the estimated IC50 was (38.20 ± 0.27) mg·mL−1 after 24 h of treatment. The body weight and the tumor volume were significantly reduced in nude mice bearing human gastric tumor treated with Xiaoaiping. The inhibition rate of tumor growth in the mid-dose (200 mg·kg−1) group and high dose (400 mg·kg−1) group were 61.19% and 69.07%, respectively. Immunohistochemical staining showed an increase in caspase-3 and Bax expression whereas Bcl-2 expression decreased gradually. Xiaoaiping exerted potent antitumor activity in vitro and in vivo against human SGC-7901 cells; induced apoptosis and G1 cell cycle arrest. These results suggest that Xiaoaiping is a promising antitumor agent for the treatment of human gastric cancer.

RKIP and 14-3-3ε Exert an Opposite Effect on Human Gastric Cancer Cells SGC7901 by Regulating the ERK/MAPK Pathway Differently

Raf-1 kinase inhibitor protein (RKIP) inhibits Raf (a key element in the ERK/MAPK pathway) and is regarded as anti-tumoral. In contrast, 14-3-3 is considered protumoral. However, the pathogenetic role of RKIP and 14-3-3ε in gastric cancer is unclear. The purpose of this study was to examine the influence of 14-3-3ε and RKIP on SGC7901, the regulation of the ERK/MAKP pathway by both, and the interaction between the two proteins. RKIP and 14-3-3ε genes were introduced into SGC7901 cells using gene cloning technique, then, the bioactivities including the proliferation, migration and invasion of the cells were assessed by MTT and migration assays. ERK/MAKP pathway's activity was examined using real-time quantitative RT-PCR, western blot, immunoprecipitation and 3D-immunolocalization techniques. Our results showed that RKIP inhibited SGC7901 cells' bioactivities whereas 14-3-3ε upregulated them through the involvement of the ERK/MAPK pathway. RKIP inactivated this pathway, but 14-3-3ε activated it. RKIP and 14-3-3ε were co-localized in the cells and interacted with each other; this attributed to their opposite influence on the ERK/MAPK pathway and the cells bioactivities. The ERK/MAPK pathway is involved in the pathogenesis of gastric cancer; RKIP and 14-3-3ε exert an opposite effect on this pathway and the cells possibly via both direct and indirect reactions with the elements in this pathway. The interaction between RKIP and 14-3-3ε may also contribute to their pathogenetic roles in gastric cancer.

Lentivirus-mediated siRNA targeting VEGF inhibits gastric cancer growth in vivo

Vascular endothelial growth factor (VEGF), a crucial promoter of blood vessel growth, not only stimulates endothelial cell proliferation, migration and survival, but also increases vascular permeability. The promotion of angiogenesis is a well-known prerequisite for tumor growth, invasion and metastasis. Evidence has shown that VEGF is overexpressed in many types of tumor tissues. Small interfering RNA (siRNA) targeting VEGF may effectively suppress cell proliferation and induce apoptosis in tumor cells. In this study, we aimed to evaluate whether lentivirus-mediated siRNA targeting VEGF inhibits gastric cancer growth in vivo. The transfection of VEGF siRNA into SGC7901 human gastric cancer cells downregulated the expression of VEGF and Bcl-2, but upregulated the expression of p21. In a nude mouse model of subcutaneous xenografts, 24 days after VEGF siRNA treatment, the tumor volume and weight were significantly smaller in the VEGF siRNA group compared to the control scrambled siRNA group. Furthermore, the expression of VEGF, sirtuin 1 (SIRT1), survivin and Bcl-2 was downregulated, whereas the expression of p53 and p21 was upregulated in the tumor cells, indicating that VEGF siRNA induced apoptosis in gastric cancer cells by inhibiting SIRT1 expression, leading to p53 transcriptional upregulation and the activation of downstream p21, while suppressing Bcl-2 and survivin expression. Our results demonstrate that lentivirus-mediated siRNA targeting VEGF offers a potential strategy to prevent the growth of gastric cancer.

Inhibitory Effects of Ethyl Pyruvate on Invasion and Metastasis of Human Gastric Cancer SGC-7901 Cells viaDownregulation of Akt Pathway

Inhibitory Effects of Ethyl Pyruvate on Invasion and Metastasis of Human Gastric Cancer SGC-7901 Cells viaDownregulation of Akt Pathway

Dihydroartemisinin induces apoptosis of human gastric cancer cells through mitochondrial pathway

Objective To investigate the molecular mechanism of induction of apoptosis by dihydroartemisinin ( DHA ) in human gastric cancer SGC7901 cells in vitro. Methods Cultured SGC7901 cells were treated with DHA at different concentrations (6.25,12.5,25.0,50.0,and 100.0 μmoL/L)for different durations (24,48,and 72 h),and then the proliferation of cells was assayed by using MTT.SGC7901 cells were treated with DHA at different concentrations for 24 h,and the cell apoptosis rate was analyzed by using flow cytometry ( FCM ).The activities of Caspase-3 and Caspase-9 were assessed by colorimetric assay.The change of mitochondrial trans-membrane potential (△Ψm) was measured by JC-1 staining.The expression levels of bcl-2 and bax were detected by using Western blotting.Western blotting was also used to reveal the amount of Cyto C in cytosol.Results Various concentrations of DHA inhibited the growth of SGC7901 cells in a dose- and time-dependent manner.After SGC7901 cells were treated with DHA for 24 h,as compared with control group ( 1.88 ±0.25),the cell apoptosis rate [(4.21 ±0.83)％,( 6.92 ± 1.26 ) ％,( 9.78 ±2.55 ) ％,( 13.93 ± 2.94)％,(16.02±3.83)％] were increased significantly and the activities of Caspase-3 (0.094 ± 0.008,0.196±0.014,0.288±0.017,0.326 ± 0.024,0.491 ±0.042) and Caspase-9 (0.082 ±0.008,0.154 ±0.010,0.176 ±0.012,0.217 ±0.015,0.268 ±0.024)were increased dose-dependently ( P＜0.05 ). As compared with control group ( 100 ),△Ψm (74.18 ±7.84,70.08 ±6.53,58.66 ± 2.38,48.79 ± 1.31,31.24 ± 0.73 ) was declined significantly ( P ＜ 0.05 ).Western blotting showed that DHA increased bax expression and decreased bcl-2 expression ( P ＜ 0.05 ).The ratio of bcl-2/bax (2.37 ±0.24,1.51 ±0.21,0.82 ±0.16,0.64 ±0.14,0.37 ±0.07) was decreased as compared with control group (3.11±0.28).Western blotting also revealed that the amount of Cyto C (0.21 ± 0.05,0.25 ± 0.06,0.38 ± 0.08,0.39 ± 0.09 ) was increased in cytosol as compared with control group (0.18 ± 0.04 ) ( P ＜ 0.05 ).Conclusion DH A induces the apoptosis of human gastric cancer SGC7901 cells dose-dependently,which is probably mediated by the mitochondrial apoptosis pathway. Key words: Dihydroartemisinin; Gastric cancer; Apoptosis; Mitochondria

Expression and Yes-Associated Protein in Gastric Adenocarcinoma and Inhibitory Effects of its Knockdown on Gastric Cancer Cell Proliferation and Metastasis

Yes-associated protein (YAP) has been implicated as an oncogene in multiple human cancers. In the present study, human gastric adenocarcinoma tissues of different grades (N=78) were collected and the mRNA and protein expression of YAP and phosphorylated YAP (p-YAP) in gastric adenocarcinomas were evaluated using immunohistochemistry, Real-time PCR and Western blot assays. Then, human gastric cancer SGC-7901 cells were stably transfected with lentivirus-mediated YAP small hairpin RNA (shRNA). The expression levels of YAP, proliferating cell nuclear antigen (PCNA) and metalloproteinase-2 (MMP-2) were detected and the effects of shRNA-mediated knockdown of YAP on cell proliferation and metastasis were assessed in gastric cancer cells. As a result, the expression of YAP was observed in 69.23 percent gastric adenocarcinoma tissues, elevating with the ascending order of tumor malignancy. Knockdown of YAP could down-regulated the expression of PCNA and MMP-2, and inhibit the proliferation and metastasis of gastric cancer cells. In conclusion, YAP is strongly expressed in gastric adenocarcinomas, and knockdown of YAP may inhibit gastric cancer cell proliferation and metastasis through down-regulation of PCNA and MMP-2 expression, suggesting that YAP represents an important therapeutic target in human gastric cancer.

Exression and PI3K/AKT Pathway in Gastric Cancer and its Blockade Suppresses Tumor Growth and Metastasis

Phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway plays a crucial role in the formation and progression of many malignancies, and has been shown to be an important therapeutic target for cancer. In the present study, human gastric adenocarcinoma tissues of different grades (N=45) were collected. The protein expression of PI3Kp85α and phosphorylated AKT (p-AKT) was evaluated immunohistochemically in the biopsy samples. PI3K/AKT pathway was blocked by constructed recombinant small hairpin RNA adenovirus vector rAd5-PI3Kp85α (rAd5-P) used to transfect into human gastric cancer SGC-7901cell line. The transfection efficiency of rAd5-P in SGC-7901 cells was observed under fluorescent microscope. The expression of PI3Kp85α, p-AKT, Ki-67 and matrix metallopeptidase-2 (MMP-2) was detected by real-time PCR and Western blot assays. Cell proliferative activities and metastatic capabilities were determined by MTT and Transwell assays. As a consequence, the protein expression of PI3Kp85α and p-AKT was respectively observed in 80.0% and 82.2% gastric adenocarcinoma tissues, elevating with the ascending order of tumor malignancy. Targeted blockade of PI3K pathway decreased the expression of PI3Kp85α, p-AKT, Ki-67 and MMP-2, and inhibited the proliferative activities and metastatic capabilities of gastric cancer cells. In conclusion, PI3Kp85α and p-AKT were strongly expressed in gastric adenocarcinoma tissues, and targeted blockade of PI3K pathway may inhibit gastric cancer growth and metastasis through down-regulation of Ki-67 and MMP-2 expression. PI3K/AKT pathway may represent an important therapeutic target for gastric cancer.

Inhibition of human gastric carcinoma cell growth in vitro by a polysaccharide from Aster tataricus

A water-soluble polysaccharide (WATP), with a molecular weight of 6.3×104Da, was isolated from Aster tataricus. According to gas chromatography (GC) analysis, WATP was composed of galactose, glucose, fucose, rhamnose, arabinose and mannose with molar ratios of 2.1:1.3:0.9:0.5:0.3:0.6. The effects of WATP on cell proliferation and apoptosis in human gastric cancer SGC-7901 cells were examined. MTT assay showed that WATP had a perfectly tumor growth inhibitory activity on SGC-7901 cells, but no cytotoxicity on SGC-7901 and primary human polymorphonuclear (PMN) cells analyzed using LDH assay. Flow cytometry analysis indicated that WATP could significantly induce apoptosis of SGC-7901 cells. Furthermore using Rh123 and Fluo-3 as fluorescent probes, respectively, it was found that mitochondrial transmembrane potential (ΔΨm) of treatment groups was significantly lower than that in un-treatment group and the concentration of calcium in cells exposed to WATP for 24h was increased in a dose dependent manner compared with unexposed group. These results suggest that WATP induces apoptosis of SGC-7901 cells through calcium- and ΔΨm-dependent pathways, indicating that it is potentially useful as a natural anti-cancer agent.

Effect of the parvovirus H-1 non-structural protein NS1 on the tumorigenicity of human gastric cancer cells

To investigate the in vivo oncosuppressive effect of the non-structural protein NS1 of parvovirus H-1 on human gastric cancer cell lines. Recombinant plasmid pcDNA3.1-NS1 containing the complete NS1 gene of parvovirus H-1 was constructed and characterized by restriction enzyme digestion and sequence analysis. The human gastric cancer cell lines MKN28, SGC7901 and MKN45 were stably transfected with empty or recombinant plasmids. NS1 gene transcription and protein expression in the latter transfectants were verified by reverse transcriptase polymerase chain reaction and Western blot, respectively. The oncosuppressive effect of the parvoviral protein NS1 on the gastric cancer cell lines was tested by comparing the tumorigenicity of empty and recombinant vector-transfected cells in nude mice. Well differentiated gastric cancer cells (MKN28) transfected with either empty plasmid or pcDNA3.1-NS1 were tumorigenic in nude mice. Moderately (SGC7901) and poorly (MKN45) differentiated gastric cancer cells transfected with empty plasmid were also tumorigenic, but no tumor resulted from the injection when they were transfected with pcDNA3.1-NS1. This NS1-associated suppression of SGC7901 and MKN45 tumors correlated with the decreased percentage of CD44 positive cells. NS1 expression in poorly differentiated gastric cancer cells prevents them from forming tumors, perhaps by impairing the stem-like phenotype. The parvoviral NS1 protein warrants further investigation for its therapeutic potential against cancer.

Construction of a novel vector expressing the fusion suicide gene yCDglyTK and hTERT-shRNA and its antitumor effects

This study aimed to construct a novel recombinant expression vector, pcDNA3.1(-)hTERT-shRNA/yCDglyTK. Its bioactivity and antitumor effects were investigated in the SGC7901 human gastric cancer cell line. Interfering RNA (RNAi) targeting human telomerase reverse transcriptase (hTERT) was applied to construct the pYr1.1-hTERT-shRNA vector. The shRNA expression cassette (including U6 promoter) was subcloned into the pcDNA3.1(-) CV-yCDglyTK vector to build a new vector, pcDNA3.1(-) hTERT-shRNA/yCDglyTK, which was identified by restriction enzyme digestion and gene sequencing. All the plasmids were delivered into SGC7901 cells using calcium phosphate nanoparticles (CPNPs). Expression of yCDglyTK and hTERT was detected by immunofluorescence, real-time PCR and western blot analysis. MTT assays were applied to measure the cytotoxic effect of the plasmids with 5-fluorocytosine (5-FC). Cell apoptosis was detected by flow cytometry. Restriction enzyme digestion and gene sequencing confirmed that the recombinant vector pcDNA3.1(-)hTERT-shRNA/yCDglyTK had been successfully constructed. Immunofluorescence, real-time PCR and western blot analysis showed that yCDglyTK was expressed, and that hTERT expression was inhibited in cells transfected with the recombinant vector. The cells transfected with the recombinant vector were the most sensitive to 5-FC and the apoptosis rates of the cells were also increased. The pcDNA3.1(-)hTERTshRNA/yCDglyTK vector was constructed successfully; it was confirmed that targeting hTERT through RNAi could synergize with suicide gene therapy.

Crosstalk between endoplasmic reticulum stress and oxidative stress in apoptosis induced by α-tocopheryl succinate in human gastric carcinoma cells

α-Tocopheryl succinate (α-TOS) has been shown to be a potent apoptosis inducer and growth inhibitor in a variety of cancer cells. Our previous studies showed the important role of endoplasmic reticulum (ER) stress and reactive oxygen species (ROS) generation in the apoptosis induced by α-TOS. However, the relationship of oxidative stress with ER stress is still controversial. The objective of the present study was to investigate the interplay between the two stress responses induced by α-TOS in SGC-7901 human gastric cancer cells. In response to α-TOS, cytological changes typical of apoptosis, induction of glucose-regulated protein 78 (GRP78) and CCAAT/enhancer-binding protein (C/EBP) homologous protein transcription factor (CHOP), and activation of caspase-4 were observed. And the antioxidant N-acetyl-l-cysteine inhibited induction of both GRP78 and CHOP by α-TOS transcriptionally and translationally. Furthermore, knocking down CHOP by RNA interference decreased ROS generation, increased glutathione level and induced glutathione peroxidase mRNA expression in α-TOS-treated cells, whereas catalase and superoxide dismutases mRNA expression were not altered. The results imply that α-TOS induces ER stress response through ROS production, while CHOP perturbs the redox state of SGC-7901 cells treated with α-TOS.

Effect of ADM on Proliferation and Apoptosis of Human Gastric Cancer Cell SGC-7901

To observe the effect of ADM on cells apoptosis of SGC-7901 cells. The SGC-7901 cells were treated by ADM. And the inhibitory ratio of cells was measured by trypan blue stain assay, the IC50 value was calculated. Cells apoptosis were detected by DNA agarose gel electrophoresis.The cell cycles were analyzed by flow cytometry system after treatment with ADM. Morphologic changes were observed using phase-contrast microscopy . The SGC-7901 cells proliferation were remarkably inhibited by ADM. The IC50 values were 5.7 μg / mL. The typical DNA ladder on agarose gel electrophoresis for analysis of cellular apoptosis were significantly appeared. ADM could restrain the SGC-7901 cells proliferation, and to cause the morphologic changes of apoptosis. Apoptosis peaks appeared with flow cytometry analysis.

TNF-α Expression in the UCB-MSCs as Stable Source Inhibits Gastric Cancers Growth in Nude Mice

Mesenchymal stem cells (MSCs) are potentially vehicles for therapy of malignant diseases. In our study, we investigated whether UCB-MSCs are capable to carry TNF-α to target tumor cells in vivo. The human gastric cancer cells SGC-7901 were subcutaneously injected into the abdomen near groins of 15 nude mice to establish experiment tumor models. MSC-TNF-α demonstrated a strong suppressive effect on the tumor growth compared with MSC and NaCl. Thus, MSC-TNF-α can obviously inhibit Gastric cancers growth in nude mice, indicating that UCB-MSCs may have the potential to become a prevention approach against gastric cancer.

Galectin-1 is up-regulated by RASSF1A gene in human gastric carcinoma cell line SGC7901

We have previously shown that overexpression of RASSF1A inhibits the growth of human gastric cancer SGC7901 cells, but the underlying mechanism remains unknown. In this study, the differential protein expression by RASSF1A gene in human gastric cancer cell line SGC7901 was determined by 2-D gel electrophoresis combined with matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) and bioinformatics. Differential expression analysis of the protein profiles by RASSF1A gene identified a total of 35 protein spots, of which 10 were up-regulated and 25 were down-regulated. Eight proteins were identified by MALDI-TOF MS: Galectin-1, TRP-14, ACBP, PSMB5, PSMB4, TIM, vimentin, CD79α. RASSF1A up-regulated the mRNA expression of Galectin-1, TRP-14, ABCP in SGC7901. RASSF1A also led to an increased expression of Galectin-1 protein in SGC7901 confirmed by western blotting and immunocytochemistry analysis. RASSF1A inhibited the activity of NF-κB in SGC7901 cells. These data indicated that Galectin-1 may be playing a role in RASSF1A signaling in SGC7901.

Resveratrol induces gastric cancer cell apoptosis via reactive oxygen species, but independent of sirtuin1

The currently available chemotherapeutic regimens against gastric cancer are not very effective, leading to high recurrence and poor survival. Resveratrol is a naturally occurring polyphenol with potent apoptosis-inducing activity. However, the mechanism underlying its actions remains unknown. In the present study, human gastric adenocarcinoma SGC7901 cells were treated with resveratrol (0, 25, 50, 100 and 200μmol/L) for 48h, and cellular apoptosis DNA damage were determined. In certain experiments, cells were incubated with superoxide dismutase (100U/mL), catalase (300U/mL) or sirtinol (10μmol/L) to determine the role of reactive oxygen species (ROS) and sirtuin1 in resveratrol-induced cellular apoptosis. Treatment with resveratrol (50-200μmol/L) for 48h significantly induced apoptosis and DNA damage in human gastric cancer SGC7901 cells. This was due to the increased generation of ROS following resveratrol treatment because incubation of cells with superoxide dismutase (100U/mL) or catalase (300U/mL) attenuated resveratrol-induced cellular apoptosis. Interestingly, treatment with resveratrol (25-200 μmol/L) did not affect the level and activity of sirtuin1, whereas the sirtuin1 inhibitor sirtinol (10μmol/L) significantly reduced sirtuin1 activity. Furthermore, treatment with sirtinol (10μmol/L) did not have any effect on apoptosis induced by resveratrol. These data provide evidence that resveratrol induces apoptosis via ROS, but independent of sirtuin1, in the human gastric cancer cell line SGC7901.

Novel 3-(1-(2-(2,7a-dihydrobenzo[d]thiazol-2-ylthio)acetyl)-5-substitutedphenyl-4,5-dihydro-1H-pyrazol-3-yl)-Coumarins: Synthesis and Anticancer Activity

Seven novel 3-(1-(2-(2,7a-dihydrobenzo[d]thiazol-2-ylthio)acetyl)-5-substituted-phenyl-4,5-dihydro-1Hpyrazol- 3-yl)-2H-chromen-2-one derivatives were synthesized and characterized by 1H NMR and 13 C NMR. All of the compounds have been screened for their anticancer activity. The bioassay tests show that compound 4g exhibited potentially high activity against human gastric cancer cell SGC-7901 with IC50 value of 6.99±1.10 μg/mL. Docking simulation was performed to position compound 4g into the telomerase (3DU6) active site to determine the probable binding model. Keywords: Coumarins, Dihydropyrazole, Molecular Docking, Anticancer activity, Telomerase, chromosomal integrity, 3DU6, gastric SGC-7901, dihydropyrazole heterocycle, Claisen-Schmidt, mother liquor, column chromatography, Cytotoxic Assay, Colorless crystals

Silencing of EphA2 inhibits invasion of human gastric cancer SGC-7901 cells in vitro and in vivo

Receptor tyrosine kinases (RTKs), the common products of transforming oncogenes, have been widely used as indicators in the genesis and progression of human tumors. Until now, the erythropoietin-producing human hepatocellular (Eph) receptors have been recognized as the largest family of RTKs. EphA2, one member of Eph receptors, locates on human chromosome 1p36.1 which is a hot region for cancer research. It has been reported that high EphA2 expression levels were correlated with the tumor metastasis and poor prognosis. Increased expression of EphA2 can promote tumor growth and enhance the metastatic potential. To further define the function of EphA2 in malignant invasion, we employed the small interference RNA (siRNA) technique to knockdown gene expression of EphA2 in the gastric cancer SGC-7901 cell. Our results showed that the expression of double stranded RNA led to the efficient and specific inhibition of endogenous EphA2 expression in SGC-7901 cells. Silencing of EphA2 expression inhibited cell proliferation, caused cell cycle arrest, and decreased cell invasion in vitro. In addition, intratumoral injection EphA2 siRNA plasmid suppressed the growth of SGC-7901 cells xenografts in nude mice. Furthermore, knockdown of EphA2 expression reduced the expression of matrix metalloproteinase-9 (MMP-9) in vitro and in vivo. In conclusion, our findings demonstrate that silencing of EphA2 inhibits gastric cancer SGC-7901 cell proliferation, invasion and MMP-9 expression, which indicate that the specific inhibition of EphA2 may be a potential approach for gastric cancer therapy.