Gastric Carcinoma Cell Line MGC-803 Research Articles

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.

Synthesis and anti-tumor activities of novel 7-O-amino acids chrysin derivatives

ObjectiveTo design and synthesize a series of chrysin derivatives and evaluate the antitumor activities with MTT assay, so as to investigate molecular structure-activity relationship with molecular docking. MethodsTarget products were synthesized with high yield by substitution reaction, hydrolysis reaction, esterification reaction, and saponification reaction in sequence, and activities of all compounds were evaluated with human gastric carcinoma cell lines MGC-803 and human breast carcinoma cell lines MCF-7 through standard MTT assay. Molecular docking results were calculated with Surflex Geom X programme of Sybyl X-2.0 version workstation. Results7-O-amino acids chrysin derivatives 6a–6l were synthesized and their inhibitory effects were evaluated by comparing the material chrysin with positive control drug 5-fluorouracil (5-FU). Among these derivatives, compound 5b (IC50 = 24.50 ± 2.26 µmol/L), 5k (IC50 = 24.30 ± 2.19 µmol/L), and 6f (IC50 = 24.61 ± 2.01 µmol/L) showed better inhibitory activities against MGC-803 cell lines, and compound 5g (IC50 = 13.15 ± 1.73 µmol/L) and 5j (IC50 = 12.34 ± 1.25 µmol/L) showed better inhibitory activities against MCF-7 cell lines than chrysin and 5-FU. Molecular docking scores showed a credible consistency compared with MTT results. ConclusionCompounds 5b, 5d, 5g, 5j, 5k, and 6f showed good antiproliferative effects on specific tumor cells, and compound 5g should be researched further when according to molecular docking.

Role of triosephosphate isomerase and downstream functional genes on gastric cancer.

Triosephosphate isomerase (TPI) is highly expressed in many types of human tumors and is involved in migration and invasion of cancer cells. However, TPI clinicopathological significance and malignant function in gastric cancer(GC) have not been well defined. The present study aimed to examine TPI expression in GC tissue and its biological functions. Furthermore, we investigated its downstream genes by gene chip technology. Our results showed that TPI expression was higher in gastric cancer tissues than adjacent tissues, although no statistical differences were found between TPI expression and clinicopathological factors. TPI overexpression in human gastric carcinoma cell line BGC-823 enhanced cell proliferation, invasion and migration, but did not change cell cycle distribution, while TPI knockdown suppressed proliferation, invasion and migration, induced apoptosis and increased G2/M arrest of human gastric carcinoma cell line MGC-803. Since the cell division cycle associated 5 (CDCA5) was identified as the one with the most decreased expression after TPI knockdown, we investigated its role in MGC-803 cells. The results showed that CDCA5 knockdown also inhibited proliferation, migration, induced apoptosis and increased G2/M arrest similarly to TPI knockdown. CDCA5 overexpression promoted MGC-803 cell proliferation, clone formation and migration abilities. These results indicated that TPI expression level might affect GC cell behavior, suggesting that both TPI and CDCA5 might be considered as potential tumor markers related with GC development and might be potential new targets in GC treatment.

MicroRNA-32 promotes gastric cancer cell proliferation and migration by inhibiting gene expression of Kruppel-like factor 4

Objective To investigate the potential role of microRNA (miRNA, miR)-32 in the regulation of gastric carcinoma cell proliferation and invasion, as well as the regulatory mechanism. Methods The level of miR-32 in gastric cancer cells and normal gastric cell line was measured by real-time fluorescent quantitative polymerase chain reaction (FQ-PCR). Gastric carcinoma cell line MGC8-03 cells were divided into four groups: miR-32 overexpression group transfected with miR-32 mimics, scramble group transfected with scramble, lent-shmiR-32 group transfected with lent-shmiR-32 and lent-vector group transfected with lent-vector by lipofectamine 2000 or lentiviral vector. The proliferation ability was measured and compared by xCELLigence. The invasion ability was measured by Transwell. The expression level of Kruppel-like factor 4 (KLF4) protein was detected by Western blotting. Results Real-time PCR results indicated that, compared to the gene expression level in the gastric normal epithelial cell GES-1, miR-32 RNA level in the five gastric cancer cell liness, including AGS, KATO-Ⅲ, MGC8-03, NCI-N87 and SGC-7901, was increased significantly (0.18±0.03 vs. 12.40±1.40, 35.80±2.10, 27.10±3.60, 6.20±1.60 and 8.50±3.50 respectively, P<0.01). The number of MGC8-03 cells in miR-32 overexpression group was significantly increased at 48 or 72 h as compared with scramble group [(160.3±5.4)% vs. (104.2±3.8)% at 48 h, P<0.01; (310.2±5.4)% vs. (107.2±2.9)% at 72 h, P<0.01]. As compared with scramble group, the number of invasion cells in miR-32 overexpression group was significantly increased as well [(327±18) vs. (113±10), P<0.01]. The cell number in lent-shmiR-32 group was less than lent-vector group at 48 or 72 h after culture [(46.5±3.9)% vs. (102.3±2.9)% at 48 h, P<0.01; (46.5±3.9)% vs. (102.3±2.9)% at 72 h, P<0.01]. Transwell results indicated that the number of invasive cells in lent-shmiR-32 group was significantly less than in lent-vector group [(41±9) vs. (99±13), P<0.01]. The expression level of KLF4 mRNA and protein in lent-shmiR-32 group was significantly higher than in lent-vector group [(10.3±1.9) vs. (1.8±0.3), P<0.01; (3.79±0.54) vs. (1.35±0.21), P<0.01]. The expression level of KLF4 protein and mRNA in miR-32 overexpression group was significantly reduced as comparing with scramble group [(0.27±0.05) vs. (1.00±0.14), P<0.01; (1.16±0.13) vs. (3.26±0.65), P<0.01]. Conclusion miR-32 promotes gastric carcinoma cell proliferation and invasion by inhibiting gene expression of KLF4. Key words: MicroRNA-32; Gastric carcinoma; Proliferation; Invasion; Kruppel-like factor 4

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.

Paeoniflorin inhibits human gastric carcinoma cell proliferation through up-regulation of microRNA-124 and suppression of PI3K/Akt and STAT3 signaling.

To examine the potential anti-tumor activity of paeoniflorin in the human gastric carcinoma cell line MGC-803. Cell viability and cytotoxic effects in MGC-803 cells were analyzed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assay, respectively. Cell apoptosis of MGC-803 cells was measured using flow cytometry, DAPI staining assay and caspase-3 activity assay. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to measure the expression of microRNA-124 (miR-124) in response to paeoniflorin. The expression of phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt), phospho-Akt (p-Akt) and phospho-signal transducer and activator of transcription 3 (p-STAT3) were also measured by quantitative RT-PCR and Western blot analysis in normal, miR-124 and anti-miR-124 over-expressing MGC-803 cells, treated with paeoniflorin. Paeoniflorin was found to inhibit MGC-803 cell viability in a dose-dependent manner. Paeoniflorin treatment was associated with the induction of apoptosis and caspase-3 activity in MGC-803 cells. Paeoniflorin treatment significantly increased miR-124 levels and inhibited the expression of PI3K, Akt, p-Akt and p-STAT3 in MGC-803 cells. Interestingly, the over-expression of miR-124 inhibits PI3K/Akt and phospho-STAT3 expressions in MGC-803 cells. PI3K agonist (IGF-1, 1 μg/10 μL) or over-expression of STAT3 reversed the effect of paeoniflorin on the proliferation of MGC-803 cells. Over-expression of anti-miR-124 in MGC-803 cells reversed paeoniflorin-induced up-regulation. In summary, the in vitro data suggest that paeoniflorin is a potential novel therapeutic agent against gastric carcinoma, which inhibits cell viability and induces apoptosis through the up-regulation of miR-124 and suppression of PI3K/Akt and STAT3 signaling.

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.

Synergistic inhibitory effect of berberine and d-limonene on human gastric carcinoma cell line MGC803.

This study aims at evaluating the anticancer effects of berberine hydrochloride (berberine) and d-limonene, alone and in combination, on human gastric carcinoma cell line MGC803 to determine whether berberine and d-limonene work synergistically and elucidate their mechanisms. MGC803 cells were treated with berberine and d-limonene, alone and in combination, for 24-48 h. The inhibitory effects of these drugs on growth were determined by MTT assay. The combination index and drug reduction index were calculated with the Chou-Talalay method based on the median-effect principle. Flow cytometry and laser scanning confocal microscopy were employed to evaluate the effects of both drugs on cell-cycle perturbation and apoptosis, generation of reactive oxygen species (ROS), mitochondrial membrane potential, and expression of Bcl-2 and caspase-3 in MGC803 cells. Berberine or d-limonene alone can inhibit the growth of MGC803 cells in a dose- and time-dependent manner. Berberine and d-limonene at a combination ratio of 1:4 exhibited a synergistic effect on anti-MGC803 cells. The two drugs distinctly induced intracellular ROS generation, reduced the mitochondrial transmembrane potential (ΔΨm), enhanced the expression of caspase-3, and decreased the expression of Bcl-2. The combination of berberine and d-limonene showed more remarkable effects compared with drugs used singly in MGC803 cells. The combination of berberine and d-limonene exerted synergistic anticancer effects on MGC803 cells by cell-cycle arrest, ROS production, and apoptosis induction through the mitochondria-mediated intrinsic pathway.

Preparation of a Novel Organoselenium Compound and Its Anticancer Effects on Cervical Cancer Cell Line HeLa

This study aims at developing new organoselenium compounds with good anticancer ability and low biotoxicity. Sucrose selenious ester (sucrose-Se) was synthesized by the reaction between sucrose and selenium oxychloride. MTT assay showed that sucrose-Se effectively inhibited the proliferation of cervical cancer cell line HeLa in a dose-dependent manner without cytostatic influence on human normal liver cell line HL-7702. Morphological observation and agarose gel electrophoresis demonstrated that sucrose-Se induced apoptosis to HeLa cells. In addition, sucrose-Se was able to inhibit proliferation of bladder carcinoma cell line 5637, human malignant melanoma cell line A375, and gastric carcinoma cell line MGC-803. Median lethal dose of sucrose-Se and sodium selenite was 290.0 and 13.1 ppm, respectively, in the acute toxicity test on mice. In conclusion, sucrose-Se has potential in cancer chemoprevention due its apoptosis induction capacity and low biotoxicity.

ABT-737 Synergizes with Arsenic Trioxide to Induce Apoptosis of Gastric Carcinoma Cells In Vitro and In Vivo

This study investigated the potential synergistic effects of two inducers of apoptosis: the small molecule ABT-737 and arsenic trioxide (ATO). Human gastric carcinoma cell lines SGC-7901 and MGC-803 were used to determine the effects of ABT-737 and ATO (alone or in combination) on cell proliferation and apoptosis in vitro. In vivo effects of these drugs were investigated in SGC-7901 solid tumours, grown in immunodeficient mice. ABT-737 and ATO inhibited proliferation and induced apoptosis in SGC-7901 and MGC-803 cells in concentration- and time-dependent manners, and showed a synergistic effect. ABT-737 disturbed the binding of B cell lymphoma (Bcl)-2 homologous antagonist killer and Bcl-extra large; ATO downregulated myeloid cell leukaemia (Mcl)-1 protein and upregulated Mcl-1short, the short splicing variant. ABT-737 and ATO significantly suppressed SGC-7901 xenograft growth, synergistically inhibited tumour growth and induced apoptosis in vivo. This study provides preclinical evidence that ABT-737 and ATO synergize to induce apoptosis of gastric carcinoma cells, suggesting that further investigation of these agents (as potential treatments for gastric cancer) is warranted.

P-0031 Pathobiological Significance of Arhi Expression in Human Gastric Carcinoma and The Precancerous Lesions as Well as Gastric Cancer Cell Lines

IntroductionAplesia Ras homologue member I (ARHI, DIRAS3) is a maternally imprinted tumor suppressor gene which is frequently lost in breast and ovarian cancers, and results in autophagic cell death of human ovarian cancer cells in vitro. There has been no report in PMC about ARHI in human gastric carcinomas and gastric cancer cell lines so far. MethodsThe ARHI expression in 309 cases of gastric carcinomas (GCs), with corresponding normal gastric mucosa and the precancerous lesions was investigated immunohistochemically, and the prognostic value of ARHI expression was analyzed. ARHI mRNA and protein expressions in gastric cancer cell lines BGC823, MGC803, SGC7901, MKN45, NCI-N87 and normal gastric epithelial cell line GES-1 were also evaluated using quantitative real time PCR(qrtPCR) and immunofluorescence (IF) methods. ResultsThe positive expression of ARHI protein in intestinal metaplasia (76.1%, 86/113), dysplasia (50.0%, 8/16) and gastric carcinoma (29.8%, 92/309) were down-regulated compared with corresponding normal gastric mucosa (87.4%, 270/309), P<0.05. The rates of ARHI up-regulated and down-regulated expression were 9.7% (30) and 67% (207), the median patients survival time of up-regulated group (62.3 months) was longer than that of down-regulated group (36.7 months). The results of qrtPCR showed that mRNA level of ARHI in the gastric carcinoma cell lines BGC-823, MGC-803 SGC-7901, MKN-45, and NCI-N87 are 0.41, 0.41, 1.39, 1.53, 0.88 fold of gastric cell line GES, respectively. ARHI protein expression detected by IF and Western blot in the cell lines mentioned above accord with the ARHI mRNA expression by qrtPCR in the study. ConclusionWe report, for the first time, that tumor suppressor ARHI expression is mainly down regulated in human gastric carcinoma and gastric dysplasia, suggesting ARHI gene plays important roles in gastric carcinogenesis, in which ARHI related autophagy may be involved. Further study is needed in this field.

P-0030 CypA Plays Roles in the Proliferation of Gastric Carcinoma Cells

ABSTRACT Introduction Cyclophilin A (CypA) is a member of the peptidyl-prolyl isomerases, the primary intracellular receptor of the immunosuppressant cyclosporin A (CsA). CypA plays an important role in life activities and participate in a variety of disease processes. Recent evidence points to possible roles for CypA overexpression in tumorigenesis. However gastric carcinoma was rarely involved in CypA research so far. Methods In this research, using immunohistochemistry assay we confirmed the overexpression of CypA in gastric carcinoma tissues at protein level. The mRNA level of CypA in gastric carcinoma cell lines are also detected by Real-Time PCR. Results Compared with normal gastric epithelial cell line GES-1, the mRNA levels of CypA in gastric carcinoma cell lines SGC-7901, MKN-45, BGC-823 and MGC-803 were 1.29, 1.46, 1.54 and 1.55 fold high respectively (Fig.1). To investigate the roles CypA plays in the occurrence and development of gastric carcinoma, we constructed 4 RNA interference vectors: pRNA-CypA shRNA 1-4 and confirmed the positive clone by PCR with pRNA primer, then sequenced the plasmid DNA for additional verification. BGC-823 cells were grown to 70% confluency in 24-well plates and transfected with 0.5ug pRNA-CypA shRNAs using Lipofectamine LTX (Invitrogen). At 48 and 96 hours following transfection the mRNA level of CypA in these cells were detected by Real-Time PCR. The results showed us that after transfection with pRNA-CypA shRNA3, BGC-823 cells yielded ∼80% and ∼30% CypA knockdown at 48h and 96h respectively compared with untreated BGC-823 cells; with pRNA-CypA shRNA2 yielded ∼27% and ∼35% CypA knockdown at 48h and 96h respectively; pRNA-CypA shRNA1 and pRNA-CypA shRNA4 had little RNA interference effects. A transient increase of CypA mRNA level occurred in transfection, and reduced to the normal level at 96h after transfection. We collected the BGC-823 cells at 48h with the best RNAi efficiency by pRNA-CypA shRNA3 plasmid to perform flow cytometric analysis of cell cycle. From the cell cycle distribution, cell populations of S & G2/M phase (M2 & M3) in untreated BGC-823cells, BGC-823cell transfected with pRNA plasmid and CypA knockdown (transfected with pRNA-CypA-shRNA3 plasmid) BGC-823cell were 45.3%, 49.7% and 33.0% respectively. CypA knockdown resulted in an augmentation of cell populations in G0/G1 phase (M1) accompanied with a decrease in S & G2/M phase (M2 & M3). Cell proliferation decreased obviously in CypA knockdown BGC-823 cells, and cell cycle arrested in G0/G1 phase (M1). These results establish the relevance of CypA to gastric carcinoma proliferation in vitro. Conclusion Our results establish the relevance of CypA to gastric carcinoma proliferation in vitro. In further study we will do more experiments to reveal mechanisms how CypA plays roles in occurrence and development of gastric carcinoma and the pathways though which the signals of CypA transfer.

Effects of morphine on PTEN expression and NF-κB activity in human gastric carcinoma cell line MGC-803

Objective To investigate the effects of morphine on PTEN expression and NF-kB activity in human gastric carcinoma cell line MGC-803. Methods The human gastric cancer cell line MGC-803 was purchased from Cell Biology Research Institute, Chinese Academy of Sciences, and cultured in DMEM liquid culture medium. The cells were randomly divided into 2 groups （ n = 6 each） ： control group and morphine group. The ceils was exposed to 0.1 μmol/L morphine in morphine group. The apoptosis was assessed by flow cytometry after being incubated with morphine for 24 h. PTEN expression and NF-kB activity were detected using RT-PCR and Western blot. Results The apoptotic rate was significantly increased, PTEN expression was up-regulated and NF- kB activity was significantly decreased in morphine group compared with control group （ P 〈 0.05）. Conclusion Morphine can promote the apoptosis in human gastric cancer cells by up-regulating PTEN expression and decreasing NF-kB activity. Key words: Morphine ; Stomach neoplasms ; Apoptosis ; PTEN phosphohydrolase ; NF-kappa B

Effects of morphine on biological characters of human gastric carcinoma cell line

Objective To explore the effects of morphine on biological characters of human gastric carcinoma cell line MGC-803. Methods MGC-803 cells were incubated with 0.1,10 or 1000 μmol/L morphine. The viability of cells was determined by MTT assay at 12, 24, 36, 48, 60, 72 h after being incubated with morphine and the proliferation of cells was measured by colony formation assay 7 days later.The cell cycle progression and apoptosis were assessed by flow cytometry. The ultrastructural changes of MGC-803 cells were observed under the transmission electron microscopy. Results The proliferation of MGC-803 cells was inhibited after incubation with morphine. Clones of gastric carcinoma cell line MGC-803 in morphine groups were fewer than those in control group. In morphine groups, the proportion of cells in G2/M was higher than that in control group. In morphine groups, apoptotic rate of MGC-803 cells was higher than in control group. Moreover, apoptotic bodies were observed in morphine groups. Conclusion Morphine can effectively inhibit growth and proliferation of gastric cancer cells and may be used as a potent therapy for gastric cancer. Key words: Morphine; Gastric carcinoma; Cell proliferation

Effect of fentanyl on viability of human gastric carcinoma cell line MGC-803

Objective To investigate the effect of fentanyl on the viability of human gastric cancer cell line MGC-803. Methods The human gastric cancer cell line MGC-803 was purchased from Cell Biology Research Institute, Chinese Academy of Sciences, and cultured in DMEM liquid culture medium. The cells were seeded in 6-well or 96-well plates and divided into 3 groups (n = 60 wells each): group Ⅰ normal control (group C); group Ⅱ and Ⅲ were exposed to fentanyl 0.01 and 1.00 μmol/L respectively (group F1, F2). The viability of the cells was detected by MTT assay after being incubated with fentanyl for 12, 24, 36, 48, 60 and 72 h. The cell cycle progression and apoptosis were assessed by flow cytometry and the ulrastructure of the cells was examined with transmission electron microscope after being incubated with fentanyl for 24 h. The proliferation of the cells was determined by colony formation assay at 7 day of incubation with fentanyl. Results The viability and proliferation of the cells and the proportion of the cells in S phase were significantly lower, while the proportion of the cella in G2/M phase and the apoptotic rate were higher in group F1 and F2 than in group C but no significant difference was found between group F1 and F2. The nuclear evelope was intact, the nucleolus and chromosomes were clearly visible in group C, while in group F1 and F2 fregmentation of nuclear envelope and nucleolus, chromatin condensation and apoptotic bodies were observed in group F2. Conclusion Fentanyl can inhibit the viability of human gastric cancer cells by its pro-apoptosis inducing effect. Key words: Fentanyl; Cell line, tumor; Cell survival

Peroxisome proliferator-activated receptor-γ is essential in the pathogenesis of gastric carcinoma

To investigate whether peroxisome proliferator-activated receptor gamma (PPAR-gamma) is expressed in human gastric carcinoma and whether PPAR-gamma is a potential target for gastric carcinoma therapy. PPAR-gamma protein in gastric carcinoma was examined by immunohistochemistry. In the gastric carcinoma cell line MGC803, PPAR-gamma, survivin, Skp2 and p27 protein and mRNA were examined by Western blotting and real-time reverse transcription-polymerase chain reaction, respectively; proliferation was examined by MTT; apoptosis was examined by chromatin staining with Hoechst 33342 and fluorescence activated cell sorting (FACS). and cell cycle was examined by FACS; the knockdown of PPAR-gamma was done by RNA interference. A high level of expression of PPAR-gamma was observed in human gastric carcinoma and in a human gastric carcinoma cell line MGC803. The PPAR-gamma agonist 15-deoxy-Delta12,14-prostaglandin J(2) (15d-PGJ(2)) inhibited growth, and induced apoptosis and G(1)/G(0) cell cycle arrest in MGC803 cells in a concentration-dependent and time-dependent manner. The effect of 15d-PGJ(2) on MGC803 cells was not reversed by the selective and irreversible antagonist GW9662 for PPAR-gamma. Furthermore, survivin and Skp2 expression were decreased, whereas p27 expression was enhanced following 15d-PGJ(2) treatment in a dose-dependent manner in MGC803 cells. Interestingly, we also found that small interfering RNA for PPAR-gamma inhibited growth and induced apoptosis in MGC803 cells. The inhibition of PPAR-gamma function may be a potentially important and novel modality for treatment and prevention of gastric carcinoma. A PPAR-gamma agonist inhibited growth of human gastric carcinoma MGC803 cells by inducing apoptosis and G(1)/G(0) cell cycle arrest with the involvement of survivin, Skp2 and p27 and not via PPAR-gamma.

Inhibition of Human Gastric Carcinoma Cell Growth in Vitro and in Vivo by Cladosporol Isolated from the Paclitaxel-Producing Strain Alternaria alternata var. monosporus

Cladosporol was isolated from the fermentation broth of Alternaria alternata var. monosporus obtained from the inner bark of the yew tree and mutated for many generations. We investigated the antitumor effects of cladosporol in vitro and in vivo. The growth-inhibitory effects of cladosporol in vitro against six human cancer cell lines were examined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. The results showed that cladosporol selectively killed cancer cells and had a significant inhibitory effect on the human gastric carcinoma cell line MGC-803 in a concentration- and time-dependent manner. In vivo, cladosporol also showed antitumor activity in nude mice bearing MGC-803 gastric cancer xenografts. These findings suggest that cladosporol has potentially useful growth inhibitory effects on human gastric carcinoma cell lines.

Effect of activation of PPARγ on cell cycle progression in human gastric carcinoma cells

Objective To investigate the effect of activation of peroxisome proliferator-activated receptor gamma (PPARγ) on cell cycle arrest of gastric carcinoma cell line MGC803.

Caudal-related homeobox 2 gene expression and its effects on human gastric carcinoma cell line

To investigate the effect of human caudal-related homeobox 2 (Cdx2) gene expression on human gastric carcinoma cell line MGC-803. pCMV-Cdx2-HA eukaryotic expression plasmid was constructed by using DNA recombinant method. The MGC-803 cells were divided into 4 groups: non-transfected, transfected with pCMV-HA, transfected with pCMV-GAPDH-HA, transfected with pCMV-Cdx2-HA. Cdx2 gene and its protein expression was detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot techniques respectively. The effects of Cdx2 overexpression on the growth of MGC-803 cells in vitro was assessed by measuring MTT, flow cytometry and transmission electron microscopy analysis. In MGC-803 cells transfected with pCMV-Cdx2-HA, cell proliferation was significantly suppressed, the cells was ultrastructurally destroyed, cell cycle progression was blocked in G0/G1 and apoptosis rate was higher (P<0.05) in comparison with non-transfected cells or cells transfected with empty vector. It indicated that Cdx2 gene can suppress the growth of gastric carcinoma and may save as a novel therapeutic target.