Gastric Carcinoma Cell Line SGC-7901 Research Articles

Helicobacter pylori promotes gastric cancer progression by upregulating semaphorin 5A expression via ERK/MMP9 signaling

Helicobacter pylori (H. pylori) infection is the strongest risk factor for the occurrence and development of gastric carcinoma. However, the molecular mechanism underlying H. pylori-induced pathogenesis has not yet been fully characterized. Here, we explored whether H. pylori upregulates semaphorin 5A to promote gastric cancer progression via the extracellular regulated protein kinases/matrix metalloproteinase (ERK/MMP9) signaling pathway. In this study, H. pylori upregulated semaphorin 5A expression in vitro and in vivo. Using the human gastric carcinoma cell lines SGC7901, SGC7901-siScrambled, and SGC7901-siSema 5A, our studies showed that H. pylori increased the proliferation, growth, migration, and invasiveness of gastric cancer cells via its effects on semaphorin 5A and that H. pylori increased the expression of MMP9 in gastric cancer cells via the semaphorin 5A-mediated ERK signaling pathway. Further analysis revealed that the ERK inhibitor PD98059 and MMP9 antibody (Ab) attenuated H. pylori-induced gastric cancer cell invasion and metastasis in vitro through a semaphorin 5A-dependent mechanism. In conclusion, H. pylori could promote gastric cancer progression in a semaphorin 5A-dependent manner via the ERK/MMP9 signaling pathway. Semaphorin 5A and its related signaling molecules potentially represent latent targets for H. pylori-related gastric cancer therapy.

Pyruvate Kinase M2 Knockdown Suppresses Migration, Invasion, and Epithelial-Mesenchymal Transition of Gastric Carcinoma via Hypoxia-Inducible Factor Alpha/B-Cell Lymphoma 6 Pathway.

Gastric carcinoma is a common malignant cancer. Pyruvate kinase M2 (PKM2) is highly expressed in cancers, including gastric carcinoma. However, its function and molecular mechanism in gastric carcinoma remains unclear. Here, we aimed to explore the function and the underlying mechanism of PKM2 on malignant phenotypes in gastric carcinoma. In this study, the mRNA levels and protein levels of PKM2 in gastric carcinoma cell lines and normal gastric mucosa epithelial cell lines were detected using quantitative real-time PCR and western blot, respectively. PKM2 was downregulated by siRNA transfection. HIF-1α or BCL-6 was upregulated by corresponding overexpression plasmid. Cell viability was detected using CCK-8 assay. Cell invasion and migration were determined using transwell assay. Higher expression of PKM2 was observed in human gastric carcinoma cell lines MKN-45 and SGC-7901 than in the normal gastric mucosa epithelial cell line GES-1. PKM2 knockdown suppressed cancer cell invasion and migration and inhibited the epithelial-mesenchymal transition (EMT) phenotype by inhibiting E-cadherin and promoting vimentin and N-cadherin expression. Also, we observed that PKM2 knockdown suppressed the hypoxia-inducible factor alpha (HIF-1α) and B-cell lymphoma 6 (BCL-6) signaling pathway. HIF-1α overexpression reversed the function of PKM2 silencing on cell invasion, migration, EMT, and BCL-6 expression. BCL-6 overexpression also reversed the function of PKM2 silencing on cell invasion, migration, and EMT but did not affect HIF-1α expression. Taken together, data from our study suggest that PKM2 knockdown impeded cell migration, invasion, and EMT of gastric carcinoma cells via the HIF-1α/BCL-6 pathway.

Formononetin exhibits anticancer activity in gastric carcinoma cell and regulating miR-542-5p.

Formononetin exhibits anti-neoplastic activities in specific types of cancers, such as colon carcinoma and breast cancer. Nevertheless, its role in suppressing gastric carcinoma (GC) growth and metastatic-associated phenotypes has not been fully understood. Here, we demonstrated that formononetin decreased the viability of GC cell line SGC-7901 and MGC-803. Furthermore, formononetin suppressed the migration and invasion abilities of GC cells. Consistent with the results in vitro, the anticancer effect of formononetin was verified using xenograft model. The expression of microRNA-542-5p (miR-542-5p), acted as an oncogene in many cancers, was identified to be upregulated in GC. Importantly, miR-542-5p might involve in formononetin exhibits anticancer activity in GC cells. Taken together, these results indicate that formononetin inhibits the growth and aggressiveness of GC cells in vitro and in vivo.

LncRNA HOTTIP promotes proliferation and inhibits apoptosis of gastric carcinoma cells via adsorbing miR-615-3p.

To explore the role of long-noncoding ribonucleic acid HOXA transcript at the distal tip (lncRNA HOTTIP) in the proliferation and apoptosis of gastric carcinoma cells. The expressions of lncRNA HOTTIP in gastric carcinoma cell lines MGC-803, HGC-27, SNU-1, and SGC-7901 and normal gastric mucosa cell line RGM-1 were detected by real-time fluorescence quantitative polymerase chain reaction (PCR) and compared. The effects of lncRNA HOTTIP on proliferation and apoptosis of gastric carcinoma cells were detected by cell counting kit-8 (CCK-8), colony formation assay, and flow cytometry, respectively. StarBase v2.0 website was adopted to predict the relationship between lncRNA HOTTIP and target miRNAs. Dual-Luciferase reporter assay was performed to verify the sponge effect of lncRNA HOTTIP on miR-615-3p. CCK-8 experiment was conducted to detect its effect on proliferation of gastric carcinoma cells after co-silencing lncRNA HOTTIP and miR-615-3p. LncRNA HOTTIP was highly expressed in gastric carcinoma cell lines MGC-803, HGC-27, SNU-1, and SGC-7901 than in normal gastric mucosa cell line RGM-1. After knockdown of lncRNA HOTTIP, the proliferation function of gastric carcinoma cells was markedly weakened, and the proportion of apoptotic cells increased. LncRNA HOTTIP was able to adsorb miR-615-3p via a sponge effect. Notably, knockdown of miR-615-3p restored the effect of silenced lncRNA HOTTIP on the proliferation function of gastric carcinoma cells. LncRNA HOTTIP is highly expressed in gastric carcinoma cells. It affects cell proliferation and apoptosis in gastric carcinoma by adsorbing miR-615-3p via a sponge effect.

The modification of ferroptosis and abnormal lipometabolism through overexpression and knockdown of potential prognostic biomarker perilipin2 in gastric carcinoma.

To investigate the biological relationship, mechanism between perilipin2 and the occurrence, advancement of gastric carcinoma, and explore the mechanism of lipid metabolism disorder leading to gastric neoplasm, and propose that perilipin2 is presumably considered as a potential molecular biomarker of gastric carcinoma. RNA-seq was applied to analyze perilipin2 and differentially expressed genes modulated by perilipin2 in neoplastic tissues of both perilipin2 overexpression and knockdown groups in vivo. The mechanism was discovered and confirmed by Rt-qPCR, immunoblotting, immunohistochemistry, staining and microassay, respectively. Cellular function experiments were performed by flow cytometry, CCK8, clonogenic assay, etc. RESULTS: Overexpression and knockdown of perilipin2 augmented the proliferation and apoptosis of gastric carcinoma cell lines SGC7901 and MGC803, respectively. The neoplastic cells with perilipin2-overexpression obtained more conspicuously rapid growth than knockdown group in vivo, and perilipin2 affected the proliferation and apoptosis of gastric carcinoma cells by modulating the related genes:acyl-coa synthetase long-chain family member 3, arachidonate 15-lipoxygenase, microtubule associated protein 1 light chain 3 alpha, pr/set domain 11 and importin 7 that were participated in Ferroptosis pathway. Moreover, RNA-seq indicated perilipin2 was an indispensable gene and protein in the suppression of Ferroptosis caused by abnormal lipometabolism in gastric carcinoma. Our study expounded the facilitation of perilipin2 in regulating the proliferation and apoptosis of gastric carcinoma cells by modification in Ferroptosis pathway, and we interpreted that the mechanism of gastric neoplasm caused by obesity, we also discovered that pr/set domain 11 and importin 7 are novel transcription factors relevant to gastric carcinoma. Furthermore, perilipin2probably serves not only as a diagnostic biomarker, but also a new therapeutic target.

Two new 8-isopentenyl isoflavane derivatives from Astragalus dolichochaete diels

Astragali Radix (Huangqi) is one of the well-known traditional Chinese medicines and has been used in China for more than two thousand years. As a close species, Astragalus dolichochaete Diels was found to possess cytotoxicity during our preliminary study of Astragalus plants from Yunnan Province, China. To better understand the chemical foundation of the cytotoxicity, the major constituents of A. dolichochaete were studied. As a result, two new 8-isopentenyl isoflavane derivatives, dolichochaeteins A and B (1 and 2), together with ten known constituents were isolated, and their structures were elucidated by means of spectroscopy, mainly 1D and 2D NMR techniques. The cytotoxic activities were evaluated for the raw extract, ethyl acetate fraction, compound 2 and glyasperin H (3) against human gastric carcinoma cell line SGC-7901, human hepatoma cell line SMMC-7721 and human leukemic cell line K562. All the samples exhibited significant cytotoxicity.

Up-regulation of miRNA-105 inhibits the progression of gastric carcinoma by directly targeting SOX9.

MicroRNAs (miRNAs) are involved in the tumorigenesis and progression of multiple tumor types and function as either tumor suppressor genes or oncogenes. This study was designed to investigate the functional behaviors and regulatory mechanisms of miR-105 in the progression of gastric carcinoma. 24 pairs of patients with gastric carcinoma were enrolled in this study. The levels of miR-105 in gastric carcinoma tissues and cells were determined using quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) assay. The biological functions of miR-105 in gastric carcinoma cell were detected by colony formation, transwell invasion and wound-healing assay. Luciferase activity assay and immunoblotting assay were applied to validate the direct target of miR-105. The expression of SRY-Box 9 (SOX9) was detected using immunofluorescence staining assay. Furthermore, the role of miR-105 on the growth of gastric carcinoma cell was examined in the established xenograft model. The role of miR-105 in the metastasis of gastric carcinoma cell in vivo, an experimental metastasis assay was performed. Herein, we proved that miR-105 was down-regulated in gastric carcinoma specimens as well as gastric cancer cells. Up-regulation of miR-105 suppressed the colony formation and aggressiveness traits of gastric carcinoma cell lines BGC823 and SGC7901 in vitro. Furthermore, over-expression of miR-105 inhibited the tumor growth as well as lung metastasis of gastric carcinoma cell in vivo. Further investigation identified SOX9 was the target gene of miR-105 in gastric cancer and its expression was negatively associated with the expression of miR-105 in gastric carcinoma tissues. Finally, overexpression of SOX9 partially reversed the influence of miR-105 on the growth and aggressiveness of gastric carcinoma cell. These results revealed the crucial role of miR-105 in the progression and metastasis of gastric carcinoma, which indicated the potential application of miR-105 in the treatment of gastric carcinoma.

Effect of trametes robiniophila on the apoptosis of human gastric carcinoma MKN-45 and SGC-7901 cells and the expressions of matrix metalloproteinase 2 and matrix metalloproteinase 9

Objective To analyze the effect of trametes robiniophila on the apoptosis and the expressions of invasion and metastasis related matrix metalloproteinase 2 (MMP-2) and MMP-9 in human gastric carcinoma poorly differentiated cell line MKN-45 and medium differentiated cell line SGC-7901. Methods Human gastric carcinoma cell lines MKN-45 and SGC-7901 incubated with trametes robiniophila at the different concentrations [0 (the negative control group), 5, 10, and 20 mg/ml] for 24 h. When bifluorescently stained with acridine orange-ethidium bromide (AO-EB), morphology was observed by using microscopy. Flow cytometry was used to test the apoptosis ratio after 24, 48, and 72 h. Reverse transcription polymerase chain reaction (RT-PCR) was applied to analyze the expressions of mRNA of MMP-2 and MMP-9 after 24 h, and the absorbance values of the bands after gel electrophoresis were used as their expression levels. Results Under the fluorescence microscope, the cells of the negative control group were green (normal cells), and the membrane was even in size and integrity. The proportion of apoptotic and necrotic cells was increased with the concentration enrichment of trametes robiniophila. The apoptotic cells were yellow, and their cell membrane lost integrity. Apoptotic bodies were found in cancer cells, and cell membrane showed bud projection. The nuclei of the apoptotic cells showed brightly condensed chromatin or fragmented. Chromatin was strongly stained and located in karyotheca. The necrotic cells were dyed red with integrity of size. The apoptotic ratio of MKN-45 cell line induced by trametes robiniophila after 24 h was (6.5±0.8)%, (14.6±1.0)%, (18.0±1.1)%, and (23.1±1.2)%, respectively (F = 333.972, P < 0.01) in negative control group and 5, 10, and 20 mg/ml trametes robiniophila group. After 48 h, the apoptotic ratio was (7.3±1.2)%, (18.3±1.6)%, (24.5±1.3)%, and (27.2±1.7)%, respectively (F = 528.432, P=0.001); after 72 h, the apoptotic ratio was (7.5±0.9)%, (50.2±1.6)%, (58.0±1.9)%, and (69.0±1.4)%, respectively(F = 3 814.238, P < 0.01). After SGC-7901 cell line induced by trametes robiniophila for 24 h, the apoptotic ratio was (12.9±1.0)%, (19.4±1.2)%, (22.0±1.7)%, and (23.0±1.9)%, respectively (F = 120.190, P < 0.01) in negative control group and 5, 10, and 20 mg/ml trametes robiniophila group. For 48 h, the apoptotic ratio was(10.2±1.3)%, (40.9±1.4)%, (51.6±1.9)%, and (66.2±1.9)%, respectively (F = 1 281.342, P < 0.01). For 72 h, the apoptotic ratio was (27.4±1.8)%, (49.7±1.4)%, (65.1±1.4)%, and (69.0±2.0)%, respectively (F = 1 112.767, P < 0.01). The induction of apoptosis showed time and dose dependence (both P < 0.01). There was a trendency that the apoptotic ratio of SGC-7901 cell line was higher than that of the MKN-45 cell line at the same condition. RT-PCR showed that mRNA relative expression level of MMP-2 was 0.64±0.02, 0.49±0.01, 0.36±0.02, and 0.32±0.01, respectively (F = 274.321, P < 0.01) of negative control group and 5, 10, and 20 mg/ml trametes extract group after the effect of trametes extract on gastric cancer MKN-45 cell line. The relative expression level of MMP-9 in MKN-45 cell line was 0.71±0.01, 0.54±0.02, 0.47±0.02, and 0.39±0.02, respectively (F = 203.948, P < 0.01). The expression level of MMP-2 in SGC-7901 cell line was 0.64±0.01, 0.42±0.02, 0.34±0.20, and 0.29±0.01, respectively (F = 305.877, P < 0.01), while the mRNA expression level of MMP-9 was 0.65±0.15, 0.47±0.01, 0.44±0.01, and 0.39±0.02, respectively (F = 265.259, P < 0.01). Compared with the negative control group, the expression levels of MMP-2 and MMP-9 of the two cell lines were both decreased, after incubated with trametes robiniophila at the different concentrations (all P < 0.05), and with the addition of concentration, the expression levels of MMP-2 and MMP-9 were decreased. Conclusion Trametes robiniophila can induce the apoptosis of human gastric carcinoma cell lines MKN-45 and SGC-7901 in vitro and can inhibit the expressions of MMP-2 and MMP-9 and the effect of trametes robiniophila may be related with the differentiation degree. Key words: Stomach neoplasms; Apoptosis; Neoplasm invasiveness; Neoplasm metastasis; Trametes robiniophila

Polyacetylenes from the Roots of Swietenia macrophylla King.

A phytochemical investigation of the roots of Swietenia macrophylla led to the isolation of seven polyacetylenes, including five new compounds (1–5) and two known ones (6–7). Their structures were elucidated by extensive spectroscopic analysis and detailed comparison with reported data. All the isolates were tested for their cytotoxicity against the human hepatocellular carcinoma cell line BEL-7402, human myeloid leukemia cell line K562, and human gastric carcinoma cell line SGC-7901. Compounds 1 and 6 showed moderate cytotoxicity against the above three human cancer cell lines with IC50 values ranging from 14.3 to 45.4 μM. Compound 4 displayed cytotoxicity against the K562 and SGC-7901 cancer cell lines with IC50 values of 26.2 ± 0.4 and 21.9 ± 0.3 μM, respectively.

Cytotoxic Tricycloalternarene Compounds from Endophyte Alternaria sp. W-1 Associated with Laminaria japonica.

The chemical investigation of the culture filtrate of endophyte Alternaria sp. W-1 associated with Laminaria japonica provided a new tricycloalternarene compound, 2H-(2E)-tricycloalternarene 12a (1), together with five known analogs: (2E)-tricycloalternarene 12a (2), tricycloalternarene 3a (3), tricycloalternarene F (4), 15-hydroxyl tricycloalternarene 5b (5), and ACTG-Toxin D (6). In vitro cytotoxicity against the human hepatocellular carcinoma cell line SMMC-7721 and the human gastric carcinoma cell line SGC-7901 was evaluated by the MTT method. Compounds 1, 3, and 4 inhibited the growth of SMMC-7721 cells with IC50 values of 49.7 ± 1.1, 45.8 ± 4.6, and 80.3 ± 3.8 μg/mL, respectively, while the IC50 value of the positive control cisplatin was 6.5 ± 0.5 μg/mL. Compounds 3 and 6 also showed moderate anti-proliferation activity against SGC-7901 cells with IC50 values of 53.2 ± 2.9 and 35.1 ± 0.8 μg/mL, respectively, while the IC50 value of cisplatin was 4.5 ± 0.6 μg/mL. Further studies revealed that the in vitro anticancer activity of compound 3 to SMMC-7721 cells was related to G1 phase cell cycle arrest and cell apoptosis, and the induced apoptosis was involved in both the mitochondrial pathway and the death receptor pathway. This is the first report on the anticancer mechanism of tricycloalternarene compounds.

CD44V6 regulates gastric carcinoma occurrence and development through up-regulating VEGF expression.

Gastric carcinoma (GC) is one of the most common malignant tumors around the world. It is featured as high morbidity, poor prognosis, and short survival, thus seriously threats to the quality of life. The mechanism of GC is still unclear, leading to a difficulty in the treatment. CD44V6 plays an important role in tumorigenesis and progression, while its role in GC still needs further elucidation. GC tissue and para-carcinoma tissue were collected from patients in different tumor-mode-metastasis (TNM) stages. CD44V6 and vascular endothelial growth factor (VEGF) expressions were detected by real-time PCR and Western blot. Their correlations with the clinicopathological characteristics of GC were analyzed. GC cell line SGC-7901 was cultured in vitro and divided into control, scramble group, and CD44V6 small interfering RNA (siRNA) group. Cell proliferation was assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Cell apoptosis was evaluated by caspase 3 activity assay. CD44V6 and VEGF protein expressions significantly increased in GC tissue compared with adjacent normal control (p < 0.05). CD44V6 expression was correlated with differentiation, lymph node metastasis, and TNM staging (p < 0.05). CD44V6 was positively correlated with VEGF (p < 0.05). CD44V6 siRNA reduced CD44V6 and VEGF expressions in SGC-7901, inhibited cell proliferation, and enhanced caspase 3 activity compared with control (p < 0.05). CD44V6 participates in GC occurrence and development by up-regulating VEGF expression. Targeting CD44V6 regulates GC progression through inhibiting VEGF expression, promoting cell apoptosis, and restraining cell proliferation.

Gastrin induces multidrug resistance via the degradation of p27Kip1 in the gastric carcinoma cell line SGC7901.

Multidrug resistance (MDR) is one of the major reasons for the failure of chemotherapy-based gastric carcinoma (GC) treatments, hence, biologically based therapies are urgently needed. Gastrin (GAS), a key gastrointestinal(GI) hormone, was found to be involved in tumor formation, progression, and metastasis. In this study, quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemical staining analysis revealed a high level of expression of GAS in drug-insensitive GC tissues (P<0.01) and similar results were revealed in GC cell lines SGC7901 and its multidrug-resistant variants SGC7901/VCR and SGC7901/ADR. We constructed a eukaryotic expression vector pCDNA3.1(+)/GAS for GAS overexpression and recombinant lentiviral vectors for specific siRNA (siGAS). Transfection of pCDNA3.1(+)/GAS increased (P<0.05) while transfection of siGAS (P<0.05) and co-treated with paclitaxel(TAX) and vincristine (VCR) combination (TAX-VCR) decreased (P<0.01) the cell viability of SGC7901, SGC7901/VCR and SGC7901/ADR. Apoptosis rates of SGC7901/VCR and SGC7901/ADR were reduced by pCDNA3.1(+)/GAS and increased by siGAS (P<0.05). The apoptosis rates of SGC7901/VCR, SGC7901/ADR and SGC7901 were all upregulated (P<0.01) when cells were co-treated with a combination of siGAS and TAX-VCR. Additionally, siGAS significantly downregulated the expression of Bcl-2 and multidrug-resistant associate protein (MRP1) and P-glycoprotein (Pgp) (P<0.05) in SGC7901/VCR and SGC7901/ADR cells. Moreover, GAS overexpression in SGC7901 cells significantly inhibited p27Kip1 expression but increased phosphorylation levels of p27Kip1 on Thr(187) and Ser(10) sites (P<0.05), as well as increasing nuclear accumulation of S-phase kinase-associated protein 2 (Skp2) and cytoplasmic accumulation of the Kip1 ubiquitination-promoting complex (KPC) (P<0.05). Silencing of Skp2 blocked the promoting effects of pCDNA3.1(+)/GAS on viability, the expression of MRP1 and Pgp and the inhibitory effects of pCDNA3.1(+)/GAS on apoptosis. In conclusion, we suggest that GAS contributes to the emergence of MDR of SGC7901 cells via the degradation of p27Kip1.

Propofol inhibits the growth and survival of gastric cancer cells in vitro through the upregulation of ING3.

Propofol is one of the most extensively used intravenous anesthetic agents and it can influence the biological behavior of gastric cancer. However, the underlying mechanism is poorly understood. In the present study, we found that propofol significantly inhibited cell proliferation, invasion and migration, and also promoted apoptosis in gastric carcinoma cell lines SGC-7901 and MGC-803, as detected using MTT, colony formation and flow cytometry assays, respectively. Moreover, propofol (10 and 20µM) markedly upregulated the expression of inhibitor of growth3 (ING3), which was lower in SGC-7901 and MGC-803 cells compared with that noted in normal human gastric epithelial cell lines GES-1 and HFE145. Furthermore, we transfected SGC-7901 and MGC-803 cells with ING3 overexpression vectors or ING3 small interference RNA (siING3), respectively, to assess the role of ING3 in propofol-induced antitumor activity. The siING3 transfection reversed the effects of propofol on the biological behavior of gastric cancer cells, while transfection of ING3 promoted the effects of propofol. In conclusion, our results indicate that propofol exerts an inhibitory effect on the growth and survival of gastric cancer cells by interfering with ING3 degradation.

Topsensterols A-C, Cytotoxic Polyhydroxylated Sterol Derivatives from a Marine Sponge Topsentia sp.

Three new polyhydroxylated sterol derivatives topsensterols A–C (1–3) have been isolated from a marine sponge Topsentia sp. collected from the South China Sea. Their structures were elucidated by detailed analysis of the spectroscopic data, especially the NOESY spectra. Topsensterols A–C (l–3) possess novel 2β,3α,4β,6α-tetrahydroxy-14α-methyl Δ9(11) steroidal nuclei with unusual side chains. Compound 2 exhibited cytotoxicity against human gastric carcinoma cell line SGC-7901 with an IC50 value of 8.0 μM. Compound 3 displayed cytotoxicity against human erythroleukemia cell line K562 with an IC50 value of 6.0 μM.

Construction of a metabolomics profile of arsenic trioxide effect in gastric carcinoma cell line SGC7901.

Arsenic trioxide (ATO) is highly effective for treating acute promyelocytic leukemia. It also holds the promise for treating solid tumors, including gastric carcinoma. However, the molecular mechanism of the effectiveness of ATO to solid tumor is still poorly understood. In this study, we chosed gastric carcinoma as an example and tried to reveal the antitumor mechanism through metabolomics. Gastric carcinoma cell line SGC7901 was treated with ATO for 6, 12, and 24 h. The global metabolite profiles were monitored by metabolomics analysis using gas chromatography (GC)/mass spectrometry (MS) and liquid chromatography/MS/MS. A total of 281 certified metabolites were reliably detected. Bioinformatics analysis showed that glycerophospholipid synthesis, one-carbon synthesis, and glutathione synthesis were affected dramatically. Other cellular functions/pathways that had been affected included inflammatory response, nicotinamide adenine dinucleotide (NAD(+)), and polyamine biosynthesis pathway. The metabolomics data from this study, in combination with previous transcriptomics and proteomics data, could serve as valuable resources for the understanding of the specific antitumor mechanism of ATO treatment.

Protective Macroautophagy Is Involved in Vitamin E Succinate Effects on Human Gastric Carcinoma Cell Line SGC-7901 by Inhibiting mTOR Axis Phosphorylation.

Vitamin E succinate (VES), a potential cancer therapeutic agent, potently induces apoptosis and inhibits the growth of various cancer cells. Autophagy has been supposed to promote cancer cell survival or trigger cell death, depending on particular cancer types and tumor microenvironments. The role of autophagy in the growth suppressive effect of VES on gastric cancer cell is basically unknown. We aimed to determine whether and how autophagy affected the VES-induced inhibition of SGC-7901 human gastric carcinoma cell growth. SGC-7901 cells were treated with VES or pre-treated with autophagy inhibitor, chloroquine (CQ) and 3-methyladenine (3-MA). Electron microscopy, fluorescence microscopy and Western blot were used to study whether VES induced autophagy reaction in SGC-7901 cells. Western blot evaluated the activities of the mammalian target of rapamycin (mTOR) axis. Then we used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry to detect the level of cell viability and apoptosis. Collectively, our data indeed strongly support our hypothesis that VES treatment produced cytological variations that depict autophagy, increased the amount of intracellular green fluorescent protein—microtubule associated protein 1 light chain 3 (GFP-LC3) punctate fluorescence and the number of autophagic vacuoles. It altered the expression of endogenous autophagy marker LC3. VES activated the suppression of mTOR through inhibiting upstream regulators p38 MAPK and Akt. mTOR suppression consequently inhibited the activation of mTOR downstream targets p70S6K and 4E-BP-1. The activation of the upstream mTOR inhibitor AMPK had been up-regulated by VES. The results showed that pre-treatment SGC-7901 with autophagy inhibitors before VES treatment could increase the capacity of VES to reduce cell viability and to provoke apoptosis. In conclusion, VES-induced autophagy participates in SGC-7901 cell protection by inhibiting mTOR axis phosphorylation. Our findings not only strengthen our understanding of the roles of autophagy in cancer biology, but may also be useful for developing new treatments for gastric cancer patients.

Lentivirus- mediated over- expression of ADP ribosylation factor guanylate kinase 1 accelerates proliferation and migration of gastric carcinoma SGC7901 cells

Objective To construct a stable over- expression lentivirus- mediated vector and transfect it into human gastric cancer cell line SGC7901 for investigating its effects on proliferation and migration of GC7901 cells. Methods ADP ribosylation factor guanylate kinase 1(ASAP1) gene coding region was cloned into lentivirus vector.Lentivirus particles were infected into the human gastric carcinoma cell line SGC7901 to upregulate the expression of ASAP1 gene.The up- regulated efficiency of targeting ASAP1 gene at mRNA level was detected by real- time quantitative polymerase chain reaction(Real- time PCR), the effect on proliferation of mesenchmal stem cells was assayed by 3-(4,5- dimethylthiazol- 2- yl)- 2, 5- diphenyltetrazolium bromide assay, and the migration ability was detected by Transwell motility assay. Results The lentiviral vector targeting ASAP1 gene was constructed successfully,and a stable human gastric cancer cell line SGC7901 line that up- regulated ASAP1 was established.Real- time quantitative PCR and Western blotting results showed that the expression of ASAP1 gene was efficiently up- regulated by infecting LV- ASAP1- GFP(P<0.01).255.4% of control group on mRNA expression and 290.2% of control group on protein expression.The 3-(4, 5- dimethylthiazol- 2- yl)- 2,5- diphenyltetrazolium bromide assay and growth curve showed that the over- expression of the ASAP1 gene successfully increased the proliferative capability of SGC7901 cells,with optical density values reaching 130.1%,136.0% and 149.1% of control group at 1,2,3 d respectively.The Transwell assay also showed similar increasing results on the migration ability(P<0.01). Conclusion The lenvivirus- mediated over- expression of the ASAP1 gene increases the proliferation and migration abilities of human gastric cancer cell line GC7901. Key words: Gastric carcinoma; ADP ribosylation factor guanylate kinase 1

The effect of zebularine on E-cadherin mRNA expression in SGC-7901 cell line

Objective To study the effect of DNA methylation inhibitor zebularine on the proliferation, migration and the expression of E- cadherin in human gastric carcinoma cell line SGC-7901. Methods Methyl thiazol tetrazolium(MTT)and the wound healing assays were used to evaluate the effect of zebularine on proliferation and migration of SGC-7901 cells. The mRNA expression of E- cadherin was detected by real- time quantitative polymerase chain reaction(Real- time PCR). Results (1)zebularine at a final concentration of 100μmol/L significantly inhibited the proliferation (0.50±0.01 vs.0.45±0.02)and migration capacity[(47.45±10.05)% vs.(88.23±5.45)%] of SGC- 7901 cells after 24 h(P< 0.05).(2)Zebularine significantly increased the mRNA expression of E- cadherin in SGC- 7901 cells after 24 h(1.02±0.10 vs.4.25±0.56,P< 0.05). Conclusion DNA methylation inhibitor zebularine can effectively decrease the proliferation and migration of SGC-7901 cells, and significantly increase the mRNA expression of E-cadherin at a final concentration of 100μmol/L after 24 h. Key words: Zebularine; E-cadherin; Gastric carcinoma

SMYD3 overexpression was a risk factor in the biological behavior and prognosis of gastric carcinoma.

SET and MYND domain-containing protein 3 (SMYD3), a histone methyltransferase, plays a key function in the progression of human cancer. However, the role of SMYD3 in gastric carcinoma carcinogenesis has yet to be elucidated. This study aimed to determine the relationships of SMYD3 expression with clinicopathological characteristics and prognosis in gastric carcinoma. The expression of SMYD3 was detected by real-time quantitative reverse transcription PCR and Western blot in gastric carcinoma (GC) cell lines, normal gastric mucosa cell line, GC tissues, and adjacent non-tumor tissues. SMYD3 expression in tissue sections of 180 gastric carcinoma samples were evaluated using immunohistochemistry. The staining results were compared with clinicopathological characteristics and to the outcome of patients. The expression levels of SMYD3 messenger RNA (mRNA) and protein in GC tissues were both higher than those in adjacent non-tumor tissues (p < 0.05). SMYD3 mRNA and protein expression levels were higher in GC cell lines MKN28, SGC7901, and MGC803 than normal gastric mucosa cell line GES-1. SMYD3 expression in gastric carcinoma was significantly correlated with primary tumor size (p < 0.001), lymph node metastasis (p < 0.001), and TNM stage (p = 0.011). Degree of differentiation [hazard ratio (HR) = 5.113; p = 0.006], serosal invasion (HR = 2.074; p = 0.024), lymph node metastasis (HR = 1.354; p < 0.001), and SMYD3 expression (HR = 0.564; p = 0.004) were identified as the independent factors of the overall survival (OS) in all enrolled GC patients. For patients with positive lymph node metastasis, degree of differentiation (HR = 5.974; p = 0.015), lymph node metastasis (HR = 1.257; p < 0.001), and SMYD3 expression (HR = 0.529; p = 0.004) were the independent prognostic factors of the OS. SMYD3 performed an important function in the aggressiveness of gastric carcinoma and may act as a promising target for prognostic prediction.

The role of B7-H1 in gastric carcinoma: clinical significance and related mechanism.

The aim of this study was to investigate the role of co-stimulatory molecule B7-H1 in gastric carcinoma, to assess its clinical significance, and to explore related mechanism. Expression of B7-H1 and interferon gamma (IFN-γ) was evaluated by immunohistochemistry in 205 gastric carcinoma tissues and nonmalignant para-carcinoma tissues and 30 normal tissues. Expression data were correlated with clinicopathologic features of the patients. Furthermore, gastric carcinoma cell line SGC7901, MGC803, and AGS were employed to assess the expression of B7-H1 under the stimulation of IFN-γ. There was no detectable or weak amount of B7-H1 in normal tissue, while 43 % (88/205) of gastric carcinoma tissues and nonmalignant para-carcinoma tissues were confirmed with B7-H1 positive (p < 0.01). High B7-H1 expression was significantly associated with the age (p < 0.01), alcohol (p < 0.05), carcinoma location (p < 0.01), and differentiation (p < 0.05). Moreover, IFN-γ and CD3(+) T cells infiltration were found in carcinoma tissues, but not in normal tissues. In addition, the expression of B7-H1 was also found in gastric carcinoma cell lines (SGC7901, MGC803 and AGS), and IFN-γ could increase its expression. Our data suggest that B7-H1 may represent a new early diagnostic marker for patients with well-differentiated gastric carcinoma. Furthermore, given its immune-inhibitory function, B7-H1 may represent a potential target in the treatment of gastric carcinoma.