Apoptosis Of MGC-803 Cells Research Articles

Expression and prognostic value of microRNA-26a and microRNA-148a in gastric cancer.

In our previous study, we demonstrated that four microRNAs (miRNAs) (miR-26a, miR-142-3p, miR-148a, and miR-195) that were downregulated in both plasma and tumor tissues were confirmed to be promising non-invasive diagnostic biomarkers for gastric cancer (GC). We used the quantitative reverse transcription polymerase chain reaction to assess the expression levels of the four miRNAs from paraffin-embedded surgical specimens of GC patients. Kaplan-Meier curves and log-rank test were applied to predict the correlation between miRNAs and cumulative overall survival (OS) of patients with GC. Besides, we performed in vitro assays including cell proliferation, migration, invasion and colony formation, and apoptosis. The median of miRNA expression in paraffin-embedded tissues were used as the cutoff value to classify patients into high or low expression groups. Down-regulation of miR-26a and miR-148a was significantly associated with shorter OS of GC patients either in the test set (miR-26a: P = 0.009; miR-148a: P = 0.005) or the validation set (miR-26a: P = 0.011; miR-148a: P = 0.024). When two sets were combined, Cox regression analysis demonstrated that both of miR-26a and miR-148a were independent prognostic factors for predicting OS of patients with GC (miR-26a: HR = 0.76, 95% CI = 0.61-0.94; miR-148a: HR = 0.73, 95% CI = 0.58-0.91). Furthermore, elevated expression of miR-26 significantly suppressed cell proliferation, migration, invasion and colony formation, and induced apoptosis of MGC-803 cells compared with negative control groups (P < 0.05). These findings supported miR-26a and miR-148a could serve as potential prognostic biomarkers for GC.

Crystal structure, cytotoxicity and action mechanism of Zn(II)/Mn(II) complexes with isoquinoline ligands

Four μ2-Cl bridged dinuclear metal complexes with isoquinoline ligands, (MPDQ)2Zn2Cl4 (1) (MPDQ=4.5-methylenedioxy-1-pyridinedihydroisoquinoline), (PYP)2Zn2Cl4 (2) (PYP=5-pyridin-2-yl-[1,3]dioxolo[4,5-g]isoquinoline), (MPDQ)2Mn2Cl4 (3),and (PYP)2Mn2Cl4 (4) were synthesized and characterized. All complexes exhibited strong proliferation inhibition activity against various cancer cells. The underlying molecular mechanisms through which they caused the cancer cell death were also elucidated. Induction of apoptosis in MGC-803 cells by complex 2 was evidenced by annexin V+/PI− detection and DiD/DAPI staining assay. Further investigation revealed that complex 2 was able to induce intrinsic pathway-dependent apoptosis in cancer cells by triggering DNA damage which was caused by the overproduction of reactive oxygen species. Based on these studies, we suggest that Zn(II) complexes containing isoquinoline ligands can be developed as candidates for anti-cancer chemotherapeutics.

Cytotoxic Activities of Fractions of the Willow Bracket Medicinal Mushroom, Phellinus igniarius (Agaricomycetes), and the Induction of Cell Cycle Arrest and Apoptosis in MGC-803 Cells.

Phellinus igniarius, a perennial medicinal mushroom, has been used in China and other countries of East Asia for the treatment of various diseases, including cancer. The purpose of this study is to evaluate the cytotoxic activities of different fractions of an ethanol extract from Ph. igniarius and to elucidate a possible antitumor mechanism. An ethanol extract of Ph. igniarius was partitioned into a petroleum ether fraction, an ethyl acetate fraction (EAF), an n-butanol fraction, and a water-soluble fraction. The cytotoxic activity of all the fractions was initially screened in a brine shrimp lethality test, then evaluated by the Cell Counting Kit-8 assay against 5 human tumor cell lines: MGC-803, BEL-7402, HeLa, MCF-7, and HCT-116. The cell cycle distribution induced by EAF on MGC-803 cells was analyzed by flow cytometry with propidium iodide staining, and apoptosis was determined using flow cytometry with Annexin V/propidium iodide staining. The results of the brine shrimp lethality test and the Cell Counting Kit-8 assay showed that EAF was the most active fraction, displaying strong inhibitory activity against the MGC-803, BEL-7402, and MCF-7 cancer cell lines. Flow cytometry analysis indicated that EAF could induce S-phase cell cycle arrest in MGC-803 cells and cause apoptosis in a concentration-dependent manner. This study demonstrated that EAF, as the most active fraction of Ph. igniarius, exerted antitumor activity by inducing MGC-803 cell apoptosis via S-phase cell cycle arrest.

Design, synthesis and biological evaluation of [1,2,3]triazolo[4,5-d]pyrimidine derivatives possessing a hydrazone moiety as antiproliferative agents

A series of [1,2,3]triazolo[4,5-d]pyrimidine derivatives bearing a hydrazone moiety were designed, synthesized and evaluated for their antiproliferative activity against several cancer cell lines of different origins by MTT assay. Most of the synthesized compounds demonstrated moderate to good activity against the cancer cell lines selected. Especially, compound 43 showed the most potent antiproliferative activity as well as good selectivity between cancer and normal cells (IC50 values of 0.85 μM against MGC-803 and 56.17 μM against GES-1). In addition, compound 43 evidently inhibited the colony formation of MGC-803 cells at 0.8 μM. Further mechanism studies revealed that compound 43 could induce apoptosis of MGC-803 cells probably through the mitochondrial pathway accompanied with decrease of the mitochondrial membrane potential (MMP), activations of caspase-9/3, up-regulation of the expression of Bax, Bak and PUMA, as well as down-regulation of that of Bcl-2 and Mcl-1.

Structurally novel steroidal spirooxindole by241 potently inhibits tumor growth mainly through ROS-mediated mechanisms.

Cancer cells always have increased ROS levels, thus making them more vulnerable to persistent endogenous oxidative stress. The biochemical difference between cancer and normal cells could be exploited to achieve selective cancer cell killing by exogenous ROS-producing agents. Herein we described a structurally novel steroidal spirooxindole by241 and its anticancer efficacy. By241 exhibited potent inhibition against human cancer cells and less toxic to normal cells. By241 concentration-dependently induced apoptosis of MGC-803 and EC9706 cells, accompanied with the mitochondrial dysfunction and increased ROS levels. NAC can completely restore the decreased cell viability of MGC-803 cells caused by by241, suggesting ROS-mediated mechanisms. The expression levels of proteins involved in the mitochondrion-related pathways were detected, showing increased expression of proapoptotic proteins and decreased expression of anti-apoptotic proteins, and activation of caspases-9/-3, but without activating caspase-8 expression. Pretreatment with Z-VAD-FMK partially rescued by241-induced apoptosis of MGC-803 cells. Additionally, by241 inhibited mTOR, activated p53 and its downstream proteins, cleaved MDM2 and PI3K/AKT as well as NF-κB signaling pathway. In vivo experiments showed that by241 did not have significant acute oral toxicity and exerted good anticancer efficacy against MGC-803 bearing mice models. Therefore, by241 may serve as a lead for further development for cancer therapy.

Synthesis and evaluation as potential antitumor agents of novel ursolic acid derivatives

Novel ursolic acid derivatives were synthesized, and their structures were confirmed by MS, IR, 1H NMR and 13C NMR spectral analysis. In vitro antitumor activities of these compounds against MGC-803 (gastric cancer cell) and Bcap-37 (breast cancer cell) human cancer cell lines were evaluated by MTT assay. The pharmacological screening results revealed that many derivatives exhibited moderate to high activities against the tested cell lines, and that most demonstrated more potent inhibitory activities than that of ursolic acid. Preliminarily mechanism study of representative compound 3h were carried out by acridine orange/ethidium bromide staining, Hoechst 33258 staining, terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling assay, and flow cytometry which indicated that compound 3h can induce cell apoptosis of MGC-803 cells, and the apoptosis ratio reached 34.59 % after 36 h treatment at 10 μM.

Investigation of antitumor mechanism of the chiral ruthenium complex Λ-[Ru(phen)2p-MOPIP]2 + in human gastric cancer MGC-803 cells

There has been a vast increase in telomerase inhibition research over the past several years, which was demonstrated as an attractive anti-tumor strategy. Our previous study found that the chiral ruthenium complex, [Ru(phen)2p-MOPIP]2+ (Phen=1,10-phenanthroline, p-MOPIP=2-(4-methoxyphenyl)-imidazo[4,5f] Markman (2003), Janaratne et al. (2007) phenanthroline) (dl-OMe) and its enantiomer Δ/Λ-[Ru(phen)2p-MOPIP]2+ (Δ/Λ-OMe) could bind to and stabilize G-quadruplex DNA structure in telomeres, and inhibit telomerase activity. In this study, cytotoxic activity of these Ru complexes was studied by MTT assay. The anti-tumor mechanisms of Λ-OMe were investigated using TRAP assay, Western blot analysis, flow cytometry, Hochest staining, and RT-PCR. Results showed that among several Ru complexes, Λ-OMe demonstrated a better anti-tumor activity against gastric cancer cell line (MGC-803), and had less effect on normal gastric epithelial cell. Λ-OMe effectively inhibited the cell growth by inhibiting cellular telomerase activity, triggering cell cycle arrest, and inducing apoptosis of MGC-803 cells. The inhibitory effect on telomerase activity was associated with the altered expression of telomere-related proteins TRF1 and TRF2. Cell-cycle arrest was associated with increased levels of P21 mRNA. Apoptosis of MGC-803 cell was triggered by modulating the expression of apoptosis-related genes Bax, Bcl-2, and caspase-3. Overall, the results suggest that Λ-OMe may be a new promising agent for human gastric cancer therapy.

Synthesis and Pharmacological Evaluation of Maleopimaric N-arylimides: Identification of Novel Proapoptotic Agents.

Several N-aryl maleopimaric acid diimides (3a-3d, 4a-4g) were synthesized and evaluated their topoisomerase I inhibitory activities along with cytotoxicities against NCI, MGC-803, Bel-7404 and Hct-116 cell lines. The pharmacological dates revealed that most of structure analogs exhibited moderate to high levels of anticancer activities against the tested cancer cell lines. Compound 4g with phenylalanine substituent exhibited significant cytotoxicity against MGC-803 and Hct-116 cells (IC50 was 9.85±1.24 and 8.47±0.95 µM, respectively). All the synthesized compounds exhibited no cytotoxicity against HUVEC cells. In addition, maleopimaric diimides showed stronger cytotoxicity and topoisomerase I inhibitory activity compared to that of maleopimaric acid. Structure-activity relationship study showed that carboxyl and diimide moieties were important to display Topo I inhibitory activities. Further experiments proved that 4g could induce apoptosis of MGC-803 cells. In addition, the further mechanisms of compound 4g-induced apoptosis in MGC-803 cells demonstrated that compound 4g induced the activations of caspase-4, caspase-8 and caspase-3 for causing cell apoptosis, and altered antiand pro-apoptotic proteins. Moreover, cell cycle analysis indicated that the derivative 4g mainly arrested MGC-803 cells in S stage.

Isobavachalcone induces the apoptosis of gastric cancer cells via inhibition of the Akt and Erk pathways.

In the present study, the MGC803 gastric cancer cell line was used as an experimental model to evaluate the potential role of isobavachalcone (IBC) in cell apoptosis, migration and invasion. The inhibitory effects of IBC on cell proliferation were determined using a methylthiazolyltetrazolium assay. Cellular morphological changes were assessed using Wright-Giemsa staining, and cell apoptosis was evaluated by flow cytometric analysis. The results of the present study demonstrated that IBC inhibited the proliferation of MGC803 cells in a concentration- and time-dependent manner. Furthermore, the wound healing and Matrigel™ Transwell® invasion assays demonstrated that IBC decreased cell migration and invasion in a concentration-dependent manner. Western blotting was used to determine the protein expression levels of caspase-3, B-cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein (Bax), as well as the key protein kinases in the Akt and extracellular signal-regulated kinase (Erk) signaling pathways. During the IBC-induced apoptosis of MGC803 cells, transient activation of phosphorylated (p)-Akt and p-Erk inhibited the activation of Akt and Erk, upregulated Bax expression, downregulated Bcl-2 expression and activated caspase-3. These results suggest that IBC inhibited the growth of MGC803 gastric cancer cells by regulating the protein expression of caspase-3, Bcl-2 and Bax. In addition, inhibition of the Akt and Erk signaling pathways may be important mechanisms underlying the IBC-induced apoptosis of gastric cancer cells.

Harmine Hydrochloride Triggers G2 Phase Arrest and Apoptosis in MGC-803 Cells and SMMC-7721 Cells by Upregulating p21, Activating Caspase-8/Bid, and Downregulating ERK/Bad Pathway.

This study aimed to investigate the effects of harmine hydrochloride (HMH) on digestive tumor cells in vitro and its molecular mechanism. MTT assays showed that HMH inhibited the proliferation of some human cancer cell lines and had no obvious inhibitory effects on human LO2 cells. Flow cytometry assays showed that HMH trigged G2 phase arrest in MGC-803 cells and SMMC-7721 cells, while the expression of cyclin A, cyclin B, p21, Myt1, and p-cdc2 (Tyr15) was upregulated. Flow cytometry assays also showed that the percentages of apoptotic cells were increased, the mitochondrial transmembrane potential (ΔΨm) decreased, and the cleavage of caspase-9, caspase-3, and poly (Adenosine diphosphate ribose) polymerase (PARP) were observed, the expression of Bad increased, phospho-Bad (S112) decreased, pro-caspase-8 was cleaved, and Bid (22 kDa) was cleaved. The expression of p-ERK decreased in both cells. In conclusion, these results demonstrated that HMH upregulates the expression of p21, activates Myt1 and inhibits cdc2 by phospho-cdc2 (Y15), and triggers G2 phase arrest in both MGC-803 cells and SMMC-7721 cells. It can also activate the mitochondria-related cell apoptosis pathway through the caspase-8/Bid pathway, inhibiting the ERK/Bad pathway and promoting apoptosis in both of these two cell types.

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.

Synthesis and biological evaluation of betulonic acid derivatives as antitumor agents

Structural modification was performed at the C-28 position of betulonic acid (BetA). Twenty-five BetA derivatives were synthesized, and evaluated for their antitumor activities against MGC-803, PC3, Bcap-37, A375, and MCF-7 human cancer cell lines by MTT assay. Among the derivatives, most of the derivatives had significant antiproliferative ability (IC50 < 19 μM). Compound 3k, the most active compound, showed IC50 values of 3.6, 5.6, 4.2, 7.8, and 5.2 μM on the five cancer cell lines respectively, and was selected to investigate cell apoptosis by subsequent florescence staining and flow cytometry analysis. The results revealed that compound 3k could induce apoptosis in MGC-803 cell lines, and the apoptosis ratios reached 28.33% after 36 h of treatment at 10 μM. In addition, the study of cancer cell apoptotic signaling pathway indicated that the apoptosis of MGC-803 cells induced by compound 3k could be through the mitochondrial intrinsic pathway.

Synthesis of new 7-O-modified chrysin derivatives and their anti-proliferative and apoptotic effects on human gastric carcinoma MGC-803 cells

Two series of 7-O-modified chrysin derivatives were prepared from 7-O-carboxymethyl chrysin(2a), 7-O-carboxypropylchrysin(2b) and short-chain alcohols by using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride(EDCI), N-hydroxybenzotriazole(HOBt) and 4-dimethylamiopryidine(DMAP) as coupling reagents. Taking cisplatin as a reference substance, their anti-proliferative activities in vitro against human gastric carcinoma MGC-803 cells were evaluated by the standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide( MTT) method. The results showed that among the compounds tested, compound hepty 4-(5-hydroxy-4-oxo-2-phenyl-4H-chromen-7-yloxy) acetate(3f) displayed the most potent growth-inhibitory effect on MGC-803 cells with half maximal inhibitory concentration(IC50) value of 3.23 μmol/L. The preliminary mechanism of inhibitory effect of compound 3f was also detected by flow cytometry(FCM), and the compound exerted anticancer activity via inducing the apoptosis of MGC-803 cells in a dose dependent manner, which suggested that compound 3f would be a potential anti-cancer agent.

Extracts of Celastrus orbiculatus exhibit anti-proliferative and anti-invasive effects on human gastric adenocarcinoma cells.

To assess the effect of Celastrus orbiculatus (COE) on growth, invasion and migration of human gastric cancer MGC-803 cells and to explore the possible mechanism. The effect of COE on cell viability, apoptosis, adhesion, invasion and migration were studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, flow cytometric, cell adhesion and transwell assay, respectively. The activity and expression of matrix metalloproteinase-9 (MMP-9) were determined by gelatin zymography, Western blot and quantitative real-time polymerase chain reaction analysis. Meanwhile, effects of COE on the expression of mitogen-activated protein kinases (MAPKs), serine threonine kinase (Akt), nuclear factor κB (NF-κB) were investigated with Western blot analysis. COE inhibited proliferation and induced apoptosis of MGC-803 cells in a dose-dependent manner. When treated with low-toxic (below 80 μg/mL) doses of COE, cell adhesion, invasion and migration were markedly suppressed. Furthermore, the gelatinolytic activity and expression of MMP-9 were also remarkably suppressed in a dose-dependent manner. In addition, upstream signaling pathways, including the phosphatidylinositol-3 kinase (PI3K)/Akt and NF-κB, were suppressed by COE. Additionally, the PI3K/Akt inhibitor, LY294002, in treating MGC-803 cells potently suppressed cell invasion and migration as well as expression of MMP-9. Similarly, the combined treatment with COE and LY294002 showed a synergistic effect compared with the treatment with COE or LY294002 alone in MGC-803 cells. COE inhibits invasion and migration of MGC-803 cells by reducing MMP-9 expression. It also inhibit PI3K/Akt and NF-κB signaling pathways, which may offer a novel approach for the treatment of human gastric cancer.

Synthesis of novel amino acid derivatives containing chrysin as anti-tumor agents against human gastric carcinoma MGC-803 cells

Two series of amino acid derivatives containing chrysin were prepared from 7-O-carboxymethyl chrysin (4a) and 7-O-carboxypropyl chrysin (4b) and amino acid methyl esters by treatment with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxybenzotriazole as coupling reagents. The anti-proliferative activities of these derivatives in vitro against human gastric carcinoma MGC-803 cells were evaluated by the standard MTT method. The results showed that among these derivatives tested, compound N-[4-(5-hydroxy-4-oxo-2-phenyl-4H-chromen-7-yloxy)butyryl]-l-isoleucine methyl ester (7c) exhibited the most potent inhibitory activity against the growth of MGC-803 cells with IC50 value of 3.78 μmol/L, comparable to the positive control cisplatin. The preliminary apoptotic mechanism of compound 7c was also investigated by flow cytometry (FCM) and Western blot analysis. Results form the FCM assay demonstrated that compound 7c could induce the apoptosis of MGC-803 cells in a dose-dependent manner. And further Western blot assay indicated that 7c could induce the apoptosis through increasing protein expression of Bax and decreasing protein expression of Bcl-xl. In summary, these results suggest that compound 7c may serve as an effective chemotherapeutic candidate.

Structural basis and anticancer properties of ruthenium-based drug complexed with human serum albumin

Ruthenium-based anticancer complexes have become increasingly popular for study over the last two decades. Although ruthenium complexes are currently being investigated in clinical trials, there are still some difficulties with their delivery and associated side effects. Human serum albumin (HSA)-based delivery systems are promising for improving anticancer drug targeting and reducing negative side effects. However, there have been few studies regarding the HSA delivery system for metal-based anticancer compounds and no mention of its structural mechanism. Therefore, we studied the structure and anticancer properties of the ruthenium-based compound [RuCl5(ind)]2− in complex with HSA. The structure revealed that [RuCl5(ind)]2− has two binding sites in HSA. In the IB subdomain, [RuCl5(ind)]2− binds to a new sub-site by coordinating with His-146. In the IIA subdomain, ruthenium (III) of [RuCl5(ind)]2− binds to the hydrophobic cavity and forms coordination bonds by replacing chlorine atoms with the His-242 and Lys-199 residues of HSA. Interestingly, [RuCl5(ind)]2−, together with HSA, can enhance cytotoxicity by two to five times in cancer cells but has no effect on normal cells in vitro. Compared with unbound drug, the HSA–[RuCl5(ind)]2− complex promotes MGC-803 cell apoptosis and also has a stronger capacity for cell cycle arrest at the G2 phase in MGC-803. In conclusion, this study will guide the rational design and development of ruthenium-containing or ruthenium-centered drugs and an HSA delivery system for ruthenium-based drugs.

Silibinin inhibits proliferation, induces apoptosis and causes cell cycle arrest in human gastric cancer MGC803 cells via STAT3 pathway inhibition.

To investigate the effect of silibinin on proliferation and apoptosis in human gastric cancer cell line MGC803 and its possible mechanisms. Human gastric cancer cell line MGC803 cells were treated with various concentration of silibinin. Cellular viability was assessed by CCK-8 assay and apoptosis and cell cycle distribution by flow cytometry. Protein expression and mRNA of STAT3, and cell cycle and apoptosis regulated genes were detected by Western blotting and real-time polymerase chain reaction, respectively. Silibinin inhibits growth of MGC803 cells in a dose- and time-dependent manner. Silibinin effectively induces apoptosis of MGC803 cells and arrests MGC803 cells in the G2/M phase of the cell cycle, while decreasing the protein expression of p-STAT3, and of STAT3 downstream target genes including Mcl-1, Bcl-xL, survivin at both protein and mRNA levels. In addition, silibinin caused an increase in caspase 3 and caspase 9 protein as well as mRNA levels. Silibinin caused G2/M phage arrest accompanied by a decrease in CDK1 and Cyclin B1 at protein and mRNA levels.. These results suggest that silibinin inhibits the proliferation of MGC803 cells, and it induces apoptosis and causes cell cycle arrest by down-regulating CDK1, cyclinB1, survivin, Bcl-xl, Mcl-1 and activating caspase 3 and caspase 9, potentially via the STAT3 pathway.

NG as a novel nitric oxide donor induces apoptosis by increasing reactive oxygen species and inhibiting mitochondrial function in MGC803 cells.

NG, O(2)-(2,4-dinitro-5-{[2-(12-en-28-β-D-galactopyranosyl-oleanolate-3-yl)-oxy-2-oxoethyl] amino} phenyl) 1-(N-hydroxyethylmethylamino) diazen-1-ium-1,2-diolate, was identified in our laboratory as a novel nitric oxide-releasing prodrug with antitumor effects. A previous study showed that NG inhibited cell growth, and induced apoptosis in HepG2 cells. In this study, the inhibitory effects of NG on the viability of MGC803 cells were examined using methylthiazolyl tetrazolium biomide (MTT) assay, neutral red assay and trypan blue exclusion test. The results showed that NG had strong cytotoxicity to induce apoptosis, which was characterized by a significant externalization of phosphatidylserine, nuclear morphological changes and enhanced Bax-to-Bcl-2 ratio. Moreover, the release of cytochrome c (Cyt c) from mitochondria and the activation of caspase-9/3 were also detected, indicating that NG may induce apoptosis through a mitochondrial-mediated pathway. NG induced mitochondrial dysfunction in MGC803 cells by altering membrane potential (△Ψm), the inhibition of complexes I, II and IV consequently decreasing ATP level. Furthermore, the treatment of MGC803 cells with NG caused a marked rise in oxidative stress as characterized by accumulation of reactive oxygen species (ROS), excessive malondialdehyde (MDA) production and a reduction in glutathione hormone (GSH) level and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity. In addition, pretreatment with N-acetylcysteine (NAC), a GSH synthesis precursor, was partially protective against the NG-induced ROS generation and cell apoptosis. In contrast, pretreatment of MGC803 cells with L-buthionine-S, R-sulfoximine (BSO), a GSH synthesis inhibitor, increased the ROS levels, and aggravated cell apoptosis by NG. These results suggest that NG-induced apoptosis in MGC803 cells is mediated, at least in part, by the increase in ROS production, oxidative stress and mitochondrial dysfunction.

DNA binding, cytotoxicity and apoptosis induction activity of a mixed-ligand copper(II) complex with taurine Schiff base and imidazole

A novel binuclear copper(II) complex (complex 1) with taurine Schiff base and imidazole has been synthesized and structurally characterized by single crystal X-ray diffraction, elemental analysis, ESI-MS spectrometry, UV–vis and IR spectroscopy. Single-crystal analysis revealed that 1 displays the sulfonate-bridged dinuclear copper(II) centers. Both copper atoms are five-coordinated and exhibit slightly distorted square pyramidal geometries. Each of copper atom is surrounded by three oxygen atoms and one nitrogen atom from different taurine Schiff base ligands, and one nitrogen atom from one imidazole ligand. The interaction between 1 and calf thymus DNA (CT-DNA) was investigated by UV–vis, fluorescence, circular dichroism (CD) spectra and agarose gel electrophoresis. The experimental results indicated that 1 could bind to CT-DNA via an intercalative mode and show efficient cleavage activity. In addition, 1 showed an antitumor effect on cell cycle and apoptosis. Flow cytometric analysis revealed that MGC-803 cells were arrested in the S phase after treatment with 1. Fluorescence microscopic observation indicated that 1 could induce apoptosis of MGC-803 cells.

Effects of Celecoxib on Cycle Kinetics of Gastric Cancer Cells and Protein Expression of Cytochrome C and Caspase-9

This investigation aimed to determine effects of celecoxib on the cell cycle kinetics of the gastric cancer cell line MGC803 and the mechanisms involved by assessing expression of cytochrome C and caspase-9 at the protein level. Cell proliferation of MGC803 was determined by MTT assay after treatment with celecoxib. Apoptosis was assessed using fluorescence staining and cell cycle kinetics by flow cytometry. Western blotting was used to detect the expression of caspase-9 protein and of cytochrome C protein in cell cytosol and mitochondria. Celecoxib was able to restrain proliferation and induce apoptosis in a dose- and time- dependent manner, inducing G0/G1 cell cycle arrest, release of cytochrome C into the cytosol, and cleavage of pro-caspase-9 into its active form. Celecoxib can induce apoptosis in MGC803 cells through a mechanism involving cell cycle arrest, mitochondrial cytochrome C release and caspase activation.