Proliferation Of MGC-803 Cells Research Articles

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

Pseudolaric acid B-induced apoptosis through p53-dependent pathway in human gastric carcinoma cells

Pseudolaric acid B (PLAB, 1), a natural diterpenoid compound, was isolated from Pseudolarix kaempferi Gordon. It has shown antifungal, antifertility, and antiangiogenic properties in previous studies. Recently, increasing evidence has confirmed that 1 exhibits antitumor effects in several tumor cell lines, but the underlying mechanism has not been fully elucidated. The aim of this study was to investigate the mechanism of PLAB-induced cell apoptosis in MGC803 cells. The results showed that 1 significantly inhibited the proliferation of MGC803 cells at 0.01–10 μM and the IC50 value was 0.91 μM for 48 h. PLAB-induced apoptosis in MGC803 cells was confirmed by DNA fragmentation assay and Hoechst33342/PI staining. PLAB-treated MGC803 cells were arrested at G 2 phase, which was associated with a marked increment of the expression of cyclin-dependent kinase inhibitor p21. The induction of p21 appeared to be transcriptionally up-regulated and was p53-dependent. In addition, PLAB induced Fas/APO-1 and caspase-3 expressions that were also correlated with apoptosis. Meanwhile, 1 decreased the mRNA expression of bcl-2, which is an antiapoptosis factor. In conclusion, 1 induced apoptosis through p53-dependent pathway in human gastric carcinoma cells. These findings suggest that 1 may be a novel promising agent for treating human gastric carcinoma.

The effects of short interfering RNAs on E2F-1 gene expression and biological behaviors of gastric cancer ceIl line MGC803

Objective To investigate the effects of RNA interference(RNAi)targeting E2F-1 on biological behaviors of gastric cancer cell line MGC803.Methods E2F-1-siRNA or negative control-siRNA was transfected into gastric cancer cell line MGC803 cells.Forty-eight h later,the expression of E2F-1 mRNA and protein in gastric cancer cell fine MGC803 was detected by real-time quantitative PCR and Western blot respectivelv.Cell cycle was examined by flow cytometry,and the proliferative rate of MGC803 cells tegted by MTT assay.Results E2F-1-siRNA effectively inhibited the expression of E2F-1 mRNA and Drotein and influenced proliferation of MGC803 cells.As compared with negative control and nontmsfected groups,the expression levels of E2F-1 mRNA and protein were decreased by 84.8%,85.3%(P＜0.05),and 77.2%,79.6%,and proliferation of MGC803 cells was suppressed by 69.0%and 81.6%(P＜0.05)in E2F-1-siRNA transfection group,respectively.E2F-1-siRNA promoted accumulation of more DNA of MGC803 cells at G2/M phase,and the rate of DNA content in G2/M phase in E2F-1-siRNA trailsfection group was(54.98±3.46)%,which was significantly higher than(43.07±3.82)% in negative control group,and(31.47±2.12)%in non-transfection group(P＜0.05).Conclusion E2F-1 gene repression by RNAi can decrease the DNA content in G1 phase of MGC803 cells,which can arrest the cells in G2/M phase and inhibit the proliferation of MGC803 cells. Key words: Gastric carcinoma; Small interfering RNA; Cell cycle; Proliferation

Macrophage migration inhibitory factor regulatesproliferation of gastric cancer cellsvia the PI3K/Akt pathway

To investigate the effects of macrophage migration inhibitory factor (MIF) on proliferation of human gastric cancer MGC-803 cells and expression of cyclin D1 and p27(Kip1) in them, and further determine whether the effects are related to the PI3K/Akt signal transduction pathway. Gastric cancer MGC-803 cells were cultured and then treated with 50 microg/L recombinant human MIF (rhMIF) with and without a PI3K inhibitor, LY294002 (25 micromol/L). MTT assay was used to detect the proliferation of MGC-803 cells. Cell cycle was detected by flow cytometry. Expression of cyclin D1 and p27(Kip1) mRNA was by reverse transcription-polymerase chain reaction. Protein expression of phosphorylated Akt (p-Akt), Akt, cyclin D1 and p27(Kip1) was examined by immunocytochemistry and Western blotting. rhMIF significantly stimulated the proliferation of MGC-803 cells and cell cycle progression from G1 phase to S phase in a concentration- and time-dependent manner. After the MGC-803 cells were treated with rhMIF for 24 h, the expression of cyclin D1 was significantly up-regulated compared with the cells not treated with rhMIF at both mRNA and protein levels (0.97 +/- 0.02 vs 0.74 +/- 0.01, P = 0.002; 0.98 +/- 0.05 vs 0.69 +/- 0.04, P = 0.003). The p27(Kip1) was down-regulated but only statistically significant at the protein level. rhMIF significantly increased the expression of p-Akt, which reached the peak at 30 min, but did not affect the expression of Akt. However, LY294002 inhibited all the effects of rhMIF. Macrophage MIF increases the proliferation of gastric cancer cells, induces the expression of cyclin D1 at the transcriptional level and inhibits the expression of p27(Kip1) at the post-transcriptional level via the PI3K/Akt pathway.

PI3K/Akt is involved in bufalin-induced apoptosis in gastric cancer cells

Bufalin is the active ingredient of the Chinese medicine Chan Su, and it has been reported that bufalin induces apoptosis in some human leukemia and solid cancer cell lines. The exact mechanism of bufalin-induced apoptosis is, however, still not clear. In this study, we demonstrated that bufalin inhibited the proliferation of gastric cancer MGC803 cells in a dose-dependent and time-dependent manner. At a low concentration (20 nmol/l), bufalin induced M-phase cell cycle arrest, whereas at a high concentration (80 nmol/l) it induced apoptosis in MGC803 cells. Bufalin increased the Bax/Bcl-2 ratio and activated caspase-3 during the apoptotic process of MGC803 cells. It should be noted that bufalin transiently activated the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway and then inhibited it completely, and upregulated the Casitas B-lineage lymphoma (Cbl) family of ubiquitin ligases, upstream modulators of PI3K. A combination of bufalin and LY294002, a PI3K-specific inhibitor, enhanced apoptosis, but PD98059, an extracellular-regulated protein kinase-specific inhibitor, had no significant effect on bufalin-induced apoptosis. These results suggested that the PI3K/Akt pathway might play a key role in bufalin-induced apoptosis in gastric cancer MGC803 cells.

Characterization and anti-tumor activity of a polysaccharide from Hedysarum polybotrys Hand.-Mazz

A water-soluble polysaccharide named as HPS-1 was isolated from the roots of Hedysarum polybotrys Hand.-Mazz by hot water extraction, anion-exchange and gel-permeation chromatography and tested for its anti-tumor activity. Its structural characteristics were investigated by FTIR, HPLC, NMR spectroscopy, GLC–MS, methylation analysis, periodate oxidation and Smith degradation. Based on the data obtained, HPS-1 was found to be an α-(1 → 4)- d-glucan, with a single α- d-glucose at the C-6 position every nine residue, on average, along the main chain. The glucan has a weight-average molecular weight of about 9.4 × 10 4 Da. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay revealed that HPS-1 significantly inhibited the proliferation of human hepatocellular carcinoma HEP-G2 cells and human gastric cancer MGC-803 cells in vitro, indicating HPS-1 could have a possible cancer therapeutic potential.

In vitro effects of chitosan nanoparticles on proliferation of human gastric carcinoma cell line MGC803 cells.

To investigate the effects of chitosan nanoparticles on proliferation of human gastric carcinoma cell line MGC803 in vitro and the possible mechanisms involved. Chitosan nanoparticles were characterized by particle size, zeta potential, and morphology. After treatment with various concentrations of chitosan nanoparticles (25, 50, 75, 100 microg/mL) at various time intervals, cell proliferation, ultrastructural changes, DNA fragmentation, mitochondrial membrane potential (MMP), cell cycle phase distribution and apoptotic peaks of MGC803 cells were analyzed by MTT assay, electron microscopy, DNA agarose gel electrophoresis, and flow cytometry. Chitosan nanoparticles exhibited a small particle size as 65 nm and a high surface charge as 52 mV. Chitosan nanoparticles markedly inhibited cell proliferation of MGC803 cells with an IC50 value of 5.3 microg/mL 48 h after treatment. After treatment with chitosan nanoparticles, the typical necrotic cell morphology was observed by electron microscopy, a typical DNA degradation associated with necrosis was determined by DNA agarose electrophoresis. Flow cytometry showed the loss of MMP and occurrence of apoptosis in chitosan nanoparticles-treated cells. Chitosan nanoparticles effectively inhibit the proliferation of human gastric carcinoma cell line MGC803 in vitro through multiple mechanisms, and may be a beneficial agent against human carcinoma.

Inhibitory and apoptosis-inducing effects of CD44 antisense oligodeoxyribonucleotides on human gastric cancer cell line MGC80-3

AIM: To study the role and mechanism of antisense oligodeoxyribonucleotides (ASODN) on proliferation and apoptosis of MGC80-3 cells. METHODS: Flow cytometry was used to detect CD44, Fas expression and apoptosis of MGC80-3 cells. Reverse transcription polymerase chain reaction (RT-PCR) assay was used to examine CD44 mRNA level; MTT assay was used to detect cell proliferation. RESULTS: CD44 mRNA and CD44 protein expression in MGC80-3 cells was blocked and down-regulated after transfected with CD44ASODN (1.6 μmol/L). CD44ASODN inhibited the growth of MGC80-3 cells with depression ratios of 31.0%, 46.3% (P0.01), and 49.6% (P0.01) at 48 h, 72 h, and 96 h respectively in a time-dependant manner. With the existence of hyaluronic acid, CD44ASODN improved Fas expression in MGC80-3 cells from 6.7% to 16.8% (P0.01). At the same time, it enhanced the susceptibility of MGC80-3 cells to Fas mAb and the apoptotic rate of the cells increased from 0% to 26.5% (P0.01). CONCLUSION: CD44ASODN can down-regulate the expression of CD44 mRNA and protein, inhibit MGC80-3 cell pro liferation and promote apoptosis induced by Fas mAb.

Vascular Endothelial Growth Factor: Acting as an Autocrine Growth Factor for Human Gastric Adenocarcinoma Cell MGC803

Vascular endothelial growth factor (VEGF) is known to be a highly specific mitogen for endothelial cells through two high-affinity tyrosine kinase receptors, VEGFR-1 and VEGFR-2, which are almost specifically expressed in endothelial cells. However, recent findings showed that VEGF receptors may also expressed by nonendothelial cells, especially by tumor cells. To further understand the functional expression of VEGF receptors by nonendothelial cells, our preliminary screening detected the expression of VEGFR-2 in 115 different paraffin-embedded cancer specimens including 35 cases of bladder tumor, 30 cases of breast cancer, 25 cases of intestinal cancer, and 25 cases of lung cancer with immunohistochemistry. The results showed that VEGFR-2 was widely expressed in different tumor tissues. By reverse transcription PCR, NCI-H23, NCI-H460, MGC803, MDA-MB-231, 293, and MCF7 cells were evaluated for the mRNA expression of both VEGF and VEGFR-2. The data indicated that all these tumor cell lines expressed detectable amounts of VEGF mRNA, but only 293, MCF7, and MGC803 cells coexpressed VEGFR-2. Immunoblot analysis also demonstrated the expression of VEGFR-2 at protein level. We further demonstrate that exogenous rhVEGF165 could stimulate cell growth in MGC803, a tumor cell line derived from gastric adenocarcinoma, in a dose- and time-dependent manner. Furthermore, the antibodies against rhVEGF165 and VEGFR-2 could block rhVEGF165-mediated proliferation of MGC803 cells. These unexpected results provided direct evidence that VEGF may act as an autocrine growth factor to induce the proliferation of gastric adenocarcinoma cells as well as tumor angiogenic cells, thus suggesting a promising tumor therapeutic application based upon the VEGF system.

10.18632/oncotarget.23613

// Hanyang Liu 1, * , Jun Song 1, * , Yan Zhou 1 , Yu Gong 1 , Liang Cao 1 , Haojun Yang 1 and Liming Tang 1 1 Department of Gastrointestinal Surgery, Nanjing Medical University Affiliated Changzhou No. 2 People’s Hospital, Changzhou, China * Co-first authors and these authors contributed equally to this work Correspondence to: Liming Tang, email: halfmoonstar@foxmail.com Haojun Yang, email: yhjmr@163.com Keywords: methylxanthine derivatives; autophagy; PTEN; PI3K/Akt/mTOR; gastric cancer Received: August 31, 2017 Accepted: November 16, 2017 Published: January 02, 2018 ABSTRACT Methylxanthine derivatives, such as caffeine and theophylline, enhance cell apoptosis and autophagy, and reportedly induce PTEN and inhibit mammalian target of rapamycin (mTOR). This study investigated the impact of caffeine and theophylline on gastric cancer cell apoptosis and autophagy using a gastric cancer cell line (MGC-803) and a nude mouse model. Peritumoral and tumor tissues were collected from five patients diagnosed with gastric carcinoma who underwent laparoscopic radical gastrectomy in our hospital. Autophagy was suppressed in gastric cancer tumors as compared to peritumoral tissues. In vitro , both caffeine and theophylline effectively suppressed MGC-803 cell proliferation and migration, and induced autophagy. To assess PTEN involvement in caffeine- and theophylline-mediated gastric cancer cell death, we transiently transfected MGC-803 cells with siRNA targeting PTEN. PTEN knockdown impaired methylxanthine derivative-mediated inhibition of PI3K/Akt/mTOR signaling. In nude mice treated with caffeine or theophylline, MGC-803 cell tumors injected with siPTEN were larger than those injected with negative control siRNA. These results show that methylxanthine derivatives (caffeine and theophylline) effectively induce gastric cancer cell apoptosis and autophagy via PTEN activation and PI3K/Akt/mTOR pathway suppression, and strongly support use of methylxanthine derivatives as potential anticancer therapeutics.