Human Gastric Carcinoma SGC-7901 Cells Research Articles

Apigenin-induced Apoptosis is Reduced via Endoplasmic Reticulum Stress and ATF6/PERK Signaling in Human Gastric Cancer Cells

Background Apigenin effectively inhibits the growth of human gastric carcinoma SGC-7901 cells and induces apoptosis as well. This study investigated the effects of ATF6 and PERK signaling pathways in unfolded protein response (UPR) and endoplasmic reticulum stress (ERS) on the apoptosis induced by apigenin in human gastric carcinoma SGC-7901 cells. Materials and Methods SGC-7901 cells were cultured with apigenin and tunicamycin for 48 h or with apigenin for 12–48 h. CCK-8 was used to determine cell viability. The mRNA expression level was detected by RT-qPCR. The expression of related proteins was explored by Western blot. The apoptosis rate of cells and cell-cycle arrest were evaluated by flow cytometer. Results The results of CCK-8 confirmed that apigenin could induce apoptosis of SGC-7901 cells. In the apigenin-treated cells group, the protein and mRNA levels of GRP78 and GRP94 dose- and time-dependently increased. Additionally, apigenin-activated UPR components PERK and ATF6. However, apigenin exerted no influence on CHOP expression or JNK activation. Pretreatment with 4-PBA significantly increased the apigenin-triggered apoptosis in SCG-7901 cells ( p < 0.05). Conclusion The results revealed the protective effect of UPR performance on apigenin-triggered apoptosis in SGC-7901 cells.

Two New Seco-Labdane Diterpenoids from the Leaves of Callicarpa nudiflora.

Two new seco-labdane diterpenoids, nudiflopene N (1) and nudiflopene O (2), and four known compounds were isolated from the leaves of Callicarpa nudiflora. The structures of the new compounds were established by 1D-, 2D-NMR, and HR-ESI-MS spectral analyses. Compounds 1–3 showed inhibitory activities on lipopolysaccharide-induced nitric oxide (NO) production in RAW264.7 cells, and new compounds 1–2 exhibited more potent inhibitory activity than compound 3. The cytotoxicity of compounds 1–3 against human hepatocellular carcinoma HepG2 cells and human gastric carcinoma SGC-7901 cells were evaluated, while all of them exhibited no cytotoxicity.

Expression of tight junction transmembrane protein Claudin-1 in gastric carcinoma and effects on tumor cell proliferation, invasion and migration

Abstract Background: Claudin-1 is involved in various cancers, but its expression and role in gastric carcinoma remain unclear. Materials and Methods: Gastric carcinoma and adjacent normal tissues were harvested from 60 patients. Claudin-1 expression was detected by RT-qPCR. The expressions in human gastric carcinoma MKN45, SGC7901 and MKN28 cells and immortalized human gastric epithelium GES-1 cells were determined by RT-qPCR and Western blotting. Claudin-1 was overexpressed in SGC7901 cells by lentiviral transfection, and they were divided into Control (untransfected), normal control (NC) (transfected with lentiviral vector) and Claudin-1 (transfected with Claudin-1 overexpression lentivirus) groups. The proliferation, invasion and migration of gastric carcinoma cells were detected through cell counting kit-8, Transwell and wound healing assays, respectively. The effects of Claudin-1 on the expressions of epithelial-mesenchymal transition (EMT) marker proteins E-cadherin and N-cadherin were detected by Western blotting. Ten 4-week-old male BALB/c nude mice were subcutaneously injected with lentivirus-treated SGC7901 cells to establish the transplanted tumor model, and the effect of overexpression of Claudin-1 was explored. Results: The expression of Claudin-1 in gastric carcinoma tissues was significantly lower than that in adjacent tissues (P<0.05). Overexpression of Claudin-1 significantly inhibited the proliferation, invasion and migration of SGC7901 cells, increased the expression of E-cadherin, and decreased that of N-cadherin (P<0.05). Overexpression of Claudin-1 in the mouse model significantly inhibited the growth of subcutaneous transplanted tumors (P<0.05). Conclusion: Claudin-1 has low expression in gastric carcinoma tissues. Overexpression of Claudin-1 inhibits the proliferation, invasion, migration, and EMT of gastric carcinoma cells, and subcutaneous tumorigenesis in nude mice.

Synthesis and evaluation of iridium(III) complexes on antineoplastic activity against human gastric carcinoma SGC-7901 cells.

The study was intended to determine the antineoplastic effects of two new iridium(III) complexes [Ir(ppy)2(PTTP)](PF6) (1) (ppy = 2-phenylpyridine) and [Ir(piq)2(PTTP)](PF6) (2) (piq = 1-phenylisoquinoline, PTTP = 2-phenoxy-1,4,8,9-tetraazatriphenylene). In MTT assay, the ligand PTTP displayed ineffective inhibition on cell growth in SGC-7901, BEL-7402, HepG2 as well as NIH3T3 cell lines, while complexes 1 and 2 showed high cytotoxic activity on SGC-7901 cells with an IC50 value of 0.5 ± 0.1µM and 4.4 ± 0.6µM, respectively. Cellular uptake, cell cloning experiments, wound healing assay and cell cycle arrest indicated that the two complexes can inhibit the cell proliferation in SGC-7901 and induce cell cycle arrest at G0/G1 phase. Additionally, reactive oxygen species (ROS) and mitochondrial membrane potential suggested that the two complexes induced cell apoptosis through disrupting mitochondrial functions. Further, western blot analysis illustrated that the two complexes caused apoptosis via regulating expression levels of Bcl-2 family proteins. Moreover, complex 1 could suppress tumor growth in vivo with an inhibitory rate of 49.41%. Altogether, these results demonstrated that complexes 1 and 2 exert a potent anticancer effect against SGC-7901 cells via mitochondrial apoptotic pathway and have a potential to be developed as antineoplastic drug candidates for human gastric cancer.

Synthesis, evaluation of biological activity studies of iridium(III) complexes against human gastric carcinoma SGC-7901 cells

Three new iridium(III) complexes [Ir(ppy)2(DBDPPZ)](PF6) (1), [Ir(bzq)2(DBDPPZ)](PF6) (2) and [Ir(piq)2(DBDPPZ)](PF6) (3) were synthesized and characterization. The cytotoxicity in vitro of the complexes against several cancer cells was evaluated by MTT method. The complexes show high anticancer activity against MDA-DB231, SGC-7901, A549 and HeLa cells. In particular, complexes 1, 2 and 3 exhibit very high cytotoxic effect on SGC-7901 cells with a very low IC50 value of 1.53 ± 0.10, 0.17 ± 0.05 and 0.30 ± 0.03 μM, respectively. The cell colonies formation, intracellular ROS, mitochondrial membrane potential, intracellular Ca2+ levels were investigated under fluorescence microscope. Studies show that the complexes can inhibit cell colonies formation, increase intracellular ROS and Ca2+ levels, induce a decrease in the mitochondrial membrane potential. The apoptosis and cell cycle arrest were also studied by flow cytometry. Additionally, the complexes can regulate the expression of caspase 3 and Bcl-2 family proteins. Taken together, the complexes induce apoptosis in SGC-7901 cells through a ROS-mediated mitochondrial dysfunction pathway.

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

Development and evaluation of a new gastroretentive drug delivery system: Nanomicelles-loaded floating mucoadhesive beads

To better treat gastric diseases and lower systemic side effect, it is essential to design new vectors to control drug release in stomach. Aiming to this challenge, we developed a new gastroretentive drug delivery system: nanomicelles-loaded gastroretentive beads. Firstly, the chitosan-coated emodin-loaded nanomicelles were developed and characterized. In vitro cytotoxicity of emodin-loaded nanomicelles, emodin suspensions and blank nanomicelles was evaluated with human gastric carcinoma SGC-7901 cells by MTT, indicating that the blank nanomicelles had null cytotoxicity and emodin-loaded nanomicelles had better antitumor efficacy compared with emodin suspensions. Secondly, nanomicelles-loaded floating mucoadhesive beads (NFM-Beads) were prepared, and the swelling, degradation, mucoadhesion and floating ability in vitro were separately investigated. FT-IR spectroscopy was applied to identify the formation of nanomicelles and NFM-Beads. Emodin release from NFM-Beads in vitro was fitted to anomalous transport mechanism. In vivo gastroretention behavior of NFM-Beads was evaluated by BaSO4-based X-ray imaging exams, showing that NFM-Beads can be retained in rabbit stomach for at least 8 h. Overall, the new NFM-Beads system could be an effective approach to improve the therapeutic potency of drug against gastric cancer.

Dual-Targeted Gold Nanoprism for Recognition of Early Apoptosis, Dual-Model Imaging and Precise Cancer Photothermal Therapy.

Photothermal therapy as novel strategy to convert near-infrared (NIR) light into heat for treatment cancers has attracted great attention and been widely studied. However, side effects and low efficiency remain the main challenge of precise cancer photothermal therapy.Methods: In this study, we have successfully fabricated and characterized the dual-targeted gold nanoprisms, whereby bare gold nanoprisms (Au NPR) were conjugated to a phenanthroline derivatives-functionalized tetraphenylethene (TPE) and further stabilized with target peptide aptamers via Au-S bonds (Au-Apt-TPE). Then, the remaining nitrogen atoms of the Au-Apt-TPE could effectively chelate with Zn2+ ions (Au-Apt-TPE@Zn) for monitoring early stage apoptotic cells.Results: The as-synthesized Au-Apt-TPE@Zn exhibited good monodispersity, size stability and consistent spectral characteristics. TPE synthesized here showed aggregation-induced emission (AIE) characteristics, and zinc conjunction (TPE@Zn) endowed Au-Apt-TPE@Zn with the cell membrane-targeted ability to selectively recognize the membranes of early stage apoptotic cells but not respond to healthy cells, which provided valuable diagnosis information on therapeutic efficacy. Au-Apt-TPE@Zn achieved specifically nuclear-targeted ability by surface decoration of AS1411 DNA aptamer. Au-Apt-TPE@Zn under NIR irradiation showed effective photothermal therapy against SGC-7901 human gastric carcinoma cells growth in vitro by inducing apoptosis through triggering reactive oxygen species (ROS) overproduction and regulating multiple signal crosstalk. In vivo studies revealed that Au-Apt-TPE@Zn under NIR irradiation showed deep penetration and dual-model imaging application (cancer-targeted fluorescence imaging and light-up photoacoustic imaging). Au-Apt-TPE@Zn under NIR irradiation also displayed strong photothermal therapy against gastric carcinoma xenograft growth in vivo by induction of apoptosis. Importantly, analysis of histopathology, hematotoxicity and immunocytotoxicity indicated that Au-Apt-TPE@Zn had less side effect and high biocompatibility.Conclusions: Our findings validated the design of using Au nanoprism with AIE materials and dual-targeted decoration could be an effective strategy in recognition of early apoptosis, dual-model imaging and precise cancer photothermal therapy.

Xanthotoxin induces apoptosis in SGC-7901 cells through death receptor pathway

ObjectiveTo investigate the effects of xanthotoxin from Apiaceae medicinal plants on cell proliferation and apoptosis, and explore its mechanism of action against human gastric carcinoma SGC-7901 cells in vitro. MethodsSGC-7901, HepG-2, MCF-7, and A549 cells were treated with different concentrations of xanthotoxin (10, 20, 60, 80, 100, 120, 140, and 160 µg/mL) for 48 h, and the cell viability (IC50) was determined by MTT assay; Xanthotoxin-induced apoptosis in cells was observed by using Hoechst 33258 Staining Kit and Annexin V-FITC Apoptosis Detection Kit; Flow cytometry was used to detect apoptosis related proteins of Fas/FasL, Bid, and DR5/TRAIL proteins in human gastric carcinoma SGC-7901 cells after being treated by xanthotoxin; The influence of xanthotoxin on Caspase-8 protein expression in the cells was determined by Flouormetric Assay Kit. ResultsXanthotoxin obviously inhibited SGC-7901, HepG-2, MCF-7, and A549 cells proliferation, and its inhibition was in a concentration-dependent manner; flow cytometry results showed that in a certain concentration range, xanthotoxin can increase the expression levels of Fas/FasL and DR5/TRAIL proteins in a concentration-dependence manner. The content of Bid protein in cells was increased, and it showed concentration-dependence. ConclusionXanthotoxin may induce SGC-7901 cells apoptosis in a certain concentration range through the Fas/FasL protein mediated death receptor pathway, or by DR5/TRAIL mediated death receptor pathway, and increase the expression level of death receptor protein, activation Caspase-8, activating downstream effect factor, inducing cell apoptosis, or activate Caspase-8 cutting activate protein Bid, and then enter the mitochondrial pathway, induction of apoptosis.

Integrin-linked kinase silencing induces a S/G2/M phases cell cycle slowing and modulates metastasis-related genes in SGC7901 human gastric carcinoma cells.

Integrin-linked kinase has been implicated in metastasis of human tumors. Recent studies have also shown that the down-regulation of integrin-linked kinase has anti-tumor potential by inhibiting the metastatic potential of several types of cultured human cancer cells. However, the mechanism by which integrin-linked kinase regulates metastasis in human gastric carcinoma is not fully clear. We investigated the effect of integrin-linked kinase deletion on metastasis-associated markers in human gastric carcinoma SGC-7901 cell lines. We generated cell lines depleted for integrin-linked kinase. Cell adhesion and invasion were measured by the MTS assay and transwell assay. The cell cycle was measured by flow cytometry. Expression of metastasis-related genes was assessed by reporter assay, quantitative RT-PCR and western blotting. Our data showed an inhibitory effect on cell adhesion and invasion after silencing of integrin-linked kinase. The cell cycle was slowed in S/G2/M phases. Metastasis-related genes E-cadherin, MMP-2/9 and cystatin B, as well as the signaling molecules p-Akt, NF-κB, and AP-1 activation, were also modulated. Our results indicate that integrin-linked kinase plays an important role in metastasis of human gastric carcinoma cells. Down-regulation of integrin-linked kinase resulted in the impairment of the metastatic potential of gastric tumor cells by regulating metastasis-related gene expression, by inhibiting the Akt pathway as well as the activity of transcription factors. Integrin-linked kinase could be used as a potential therapeutic target.

Resveratrol induced apoptosis in human gastric carcinoma SGC-7901 cells via activation of mitochondrial pathway.

Resveratrol is a natural polyphenolic compound and its anticancer effect has been receiving considerable attention. Previous studies showed that resveratrol could inhibited the growth of human gastric carcinoma cells and apoptosis induction was an important mechanism. However, whether mitochondrial pathway was involved in resveratrol-induced apoptosis in human gastric cancer was not very clear. The cells were examined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, Annexin V/PI staining assay, mitochondrial membrane depolarization, cell morphological assessment, cytochrome c release assay, and Western blotting assay. In this study, we found that resveratrol induced apoptosis in human gastric carcinoma SGC-7901 cells. Cleaved PARP was observed and caspase-3 was activated by resveratrol. Next, the mitochondrial membrane potential of cells dissipated after the cells were treated by resveratrol. Moreover, we found that pro-caspase 9 was downregulated and cytochrome c released from mitochondrial to the cytosol. We also found that the expression ratio of Bax/Bcl-2 was increased in the treated cells. We finally showed that resveratrol inhibited the proliferation of SGC-7901 xerograph in vivo. Collectively, our findings demonstrate that resveratrol triggers apoptosis via mitochondrial pathway in SGC-7901 cells, which provide more basis for resveratrol acting as antitumor agents in cancer therapy.

Establishment of a Model of Microencapsulated SGC7901 Human Gastric Carcinoma Cells Cocultured with Tumor-Associated Macrophages

The important factors of poor survival of gastric cancer (GC) are relapse and metastasis. For further elucidation of the mechanism, a culture system mimicking the microenvironment of the tumor in humans was needed. We established a model of microencapsulated SGC7901 human GC cells and evaluated the effects of coculturing spheres with tumor-associated macrophages (TAMs). SGC7901 cells were encapsulated in alginate-polylysine-sodium alginate (APA) microcapsules using an electrostatic droplet generator. MTT assays showed that the numbers of microencapsulated cells were the highest after culturing for 14 days. Metabolic curves showed consumption of glucose and production of lactic acid by day 20. Immunocytochemistry confirmed that Proliferating Cell Nuclear Antigen (PCNA) and Vascular Endothelial Growth Factor (VEGF) were expressed in microencapsulated SGC7901 cells on days 7 and 14. The expression of PCNA was observed outside spheroids; however, VEGF was found in the entire spheroids. PCNA and VEGF were increased after being cocultured with TAMs. Matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) expressions were detected in the supernatant of microencapsulated cells cocultured with TAMs but not in microencapsulated cells. Our study confirms the successful establishment of the microencapsulated GC cells. TAMs can promote PCNA, VEGF, MMP-2, and MMP-9 expressions of the GC cells.

Toosendanin suppresses oncogenic phenotypes of human gastric carcinoma SGC‑7901 cells partly via miR‑200a‑mediated downregulation of β-catenin pathway.

Aberrant activation of β-catenin signaling due to low expression of miR‑200a is found in gastric carcinoma(GC) tissues promoting GC evolution. Toosendanin(TSN) has exhibited antitumor effects on various human cancer cells, but its influence on GC is largely unidentified. The potential roles of TSN on GC cells were examined and it was found that TSN inhibited growth, migration, invasion and TGF‑β1-induced epithelial-mesenchymal transition (EMT) and induced cell cycle arrest and apoptosis in SGC‑7901 cells which were most sensitive to TSN among various GC cell lines. TSN also inactivated β-catenin pathway in SGC‑7901 cells and the above effects were reversed following induction of β-catenin overexpression. Moreover, TSN facilitated the level of miR‑200a which targets β-catenin and miR‑200a silencing attenuated the antitumor effects of TSN on SGC‑7901 cells. Nonetheless, knockdown of miR‑200a did not relieve the suppressive effects of TSN on p‑AKT, p‑ERK and p‑GSK3β which were upstream regulators of β-catenin. In addition, TSN administration inhibited growth and liver metastasis of orthotopically implanted SGC‑7901 tumors invivo through miR‑200a‑mediated β-catenin pathway. Our data suggest that TSN may suppress oncogenic phenotypes of human GC cells partly via miR‑200a/β-catenin axis. Hence, TSN may have a promising chemotherapeutic activity for GC therapy.

Anticancer and anti-angiogenic activities of extract from Actinidia eriantha Benth root

Ethnopharmacological relevanceThe roots of Actinidia eriantha Benth (AER) are commonly used traditional folk medicine for the treatment of gastric carcinoma, nasopharyngeal carcinoma, and breast carcinoma. Besides, the anti-proliferative and immunomodulatory effects of AER polysaccharides on tumor-bearing mice have been reported previously. Aim of the studyThis work was carried out to investigate the anticancer and anti-angiogenic activities of AER. Materials and methodsThe growth inhibitory effects of ethanol extracts from the leaves (EEL), stems (EES) and roots (EER) of A. eriantha on human gastric carcinoma SGC7901 cells, human nasopharyngeal carcinoma CNE2 cells, human breast carcinoma MCF7 cells and human umbilical vein endothelial cells (HUVECs) were evaluated by MTT assay. The ethyl acetate fraction from EER (EA-EER) was further investigated for the anticancer activity against SGC7901 cells and the anti-angiogenic activity in HUVECs in vitro. The apoptosis in SGC7901 cells and HUVECs was confirmed by DAPI nuclear staining and flow cytometry analysis, the effect on cellular DNA fragmentation was detected in SGC7901 cells. And the cell cycle-arresting activity in HUVECs was determined by flow cytometry. Moreover, the inhibitory effect of EA-EER on cell migration in HUVECs was observed by both wound-healing and Transwell migration assays. RT-PCR and Western-blotting were performed to determine the mRNA and protein expression levels, respectively, including Bax, Bcl-2 and caspase-3 in SGC7901 cells, as well as VEGF-A and VEGFR-2 in HUVECs. Furthermore, the in vivo anti-angiogenic activity of EA-EER was evaluated by using chick embryo chorioallantoic membrane (CAM) assay. Ultimately, the chemical components in EA-EER were isolated and purified by repeated column chromatography followed by structure characterization using 1H and 13C nuclear magnetic resonance and mass spectroscopy. ResultsCompared with EEL and EES, EER displayed the strongest growth inhibitory effect on SGC7901 cells, CNE2 cells and HUVECs. Among the EER fractions, EA-EER exhibited the most potent growth inhibitory activity against SGC7901 cells, CNE2 cells and HUVECs. Moreover, EA-EER induced obvious apoptosis in SGC7901 and HUVECs, and significantly inhibited the proliferation of HUVECs via blockade of cell cycle G1 to S progression. Furthermore, EA-EER suppressed the expression of Bcl-2 and improved the expression Bax and caspase-3 in SGC7901 cells. EA-EER not only inhibited migration of HUVECs, but also down-regulated the expression of VEGF-A and VEGFR-2 in HUVECs. In vivo, EA-EER exposure reduced the formation of blood vessels in chick embryos. A bio-guided isolation of EA-EER led to the isolation of three compounds for the first time, namely (6R, 7E, 9S)-6, 9-hydroxy-megastigman-4, 7-dien-3-one-9-O-β-D-glucopyranoside, Oleanolic acid-23-O-β-D-glucopyranoside, 3β, 23, 24-trihydroxyl-12-oleanen-28-oic acid. ConclusionThe present research demonstrated that the significant anticancer and anti-angiogenic effects of AER, providing the supportive evidence for its traditional use in the treatment for cancer. It was suggested that AER could be use as a potential source of cancer therapeutic drug.

Embelin induces apoptosis of human gastric carcinoma through inhibition of p38MAPK and NF-κB signaling pathways.

Embelin is a small-molecule inhibitor of X‑linked inhibitor of apoptosis protein (XIAP), and it induces apoptosis in tumor cells via the inhibition of XIAP. The aim of the present study was to investigate the anticancer effect of embelin on human gastric carcinoma cells and the mechanisms underlying this effect. Cell proliferation of SGC7901 human gastric carcinoma cells was measured using MTT assay, following treatment with embelin (5, 10and 15µM) on days1,3 and5. Caspase‑3 and nuclear factor (NF)‑κBp65 activation in SGC7901cells were assessed using commercial kits. Cellular and nuclear apoptosis were analyzed with an AnnexinV‑FITC/PI Apoptosis Detection kit and DAPI staining assay, respectively. Phospho(p)‑p38 mitogen‑activated protein kinase (MAPK), p‑inhibitor of NF‑κB (p‑IκBα) and p‑IκB kinaseα/β (p‑IKKα/β) protein expression levels were analyzed with western blot assay. In the present study, treatment with embelin decreased cell proliferation, induced caspase‑3 activation and suppressed NF‑κBp65 activation in SGC7901cells. Furthermore, embelin administration reduced p‑IκBα and p‑IKKα/β protein expression levels. In conclusion, embelin induces cell apoptosis in human gastric carcinoma through activation of p38MAPK and inhibition of the NF‑κB signaling pathways. It was further suggested that embelin may be used as a potential drug for the treatment of gastric carcinoma.

Organic two-photon nanoparticles modulate reactive oxygen species, intracellular calcium concentration, and mitochondrial membrane potential during apoptosis of human gastric carcinoma SGC-7901 cells

To investigate the biocompatibility of human gastric carcinoma cells (SGC-7901) with organic two-photon nanoparticles (NPs). Different concentrations of NPs were incubated with SGC-7901 cells for different times. The levels of cell apoptosis, reactive oxygen species (ROS), intracellular calcium, and mitochondrial membrane potential (MMP) were measured by staining the SGC-7901 cells with Annexin V-FITC/PI, 2',7'-dichlorofluorescin diacetate, Fluo-3 AM, and Rhodamine 123, followed by the flow cytometry assay. NPs at <4µg/ml, did not have any significant effect on apoptosis, necrosis, generation of ROS, increase of intracellular Ca(2+) concentration or decrease of MMP in SGC-7901 cells, but >4µg/ml had a major effects on all the above mentioned parameters. 2,5,2',5'-Tetra(4-N,N-diphenylamine styryl) biphenyl NPs can be used at an appropriate concentration as a safe drug carrier or imaging marker and may serve as an effective tool for developing a photodynamic cancer therapy.

Potent effects of dioscin against gastric cancer in vitro and in vivo

BackgroundWe previously reported the effect of dioscin on human gastric carcinoma SGC-7901 cells, but its effects on other gastric cancers are still unknown. PurposeThe present paper aimed to demonstrate the activity of dioscin against human gastric carcinoma MGC-803 and MKN-45. Study designIn our study, MGC-803 and MKN-45 cells were used to examine the effects of dioscin on human gastric carcinoma in vitro. The effects of dioscin against human gastric carcinoma in vivo were accomplished by the xenografts of MGC-803 cells in BALB/c nude mice. MethodsAO/EB and DAPI staining, TEM, single cell gel electrophoresis and flow cytometry assays were used in cell experiments. Then, an iTRAQ-based proteomics approach, DNA and siRNA transfection experiments were carried out for mechanism investigation. ResultsIn MGC-803 cells, dioscin caused DNA damage and mitochondrial change, induced ROS generation, Ca2+ release and cell apoptosis, and blocked cell cycle at S phase. In vivo results showed that dioscin significantly suppressed the tumor growth of MGC-803 cell xenografts in nude mice. In addition, dioscin markedly inhibited cell migration, caused Cytochrome c release and adjusted mitochondrial signal pathway. Then, an iTRAQ-based proteomics approach was carried out and 121 differentially expressed proteins were found, in which five biomarkers associated with cell cycle, apoptosis and migration were evaluated. Dioscin significantly up-regulated the levels of GALR-2 and RBM-3, and down-regulated CAP-1, Tribbles-2 and CliC-3. Furthermore, overexpressed DNA transfection of CAP-1 enhanced cell migration and invasion, which was decreased by dioscin. SiRNA to Tribbles-2 affected the protein levels of Bcl-2, Bax and MAPKs, suggesting that dioscin decreased Tribbles-2 level leading to cell apoptosis. ConclusionOur works confirmed the activity of dioscin against gastric cancer. In addition, this work also provided that dioscin is a new potent candidate for treating gastric cancer in the future.

Apoptosis of human gastric carcinoma cells induced by Euphorbia esula latex.

To investigate the effect of Euphorbia esula (E. esula) extract in inhibiting proliferation and inducing apoptosis in SGC-7901 cells. E. esula extract at different concentrations was used to inhibit proliferation and induce apoptosis of human gastric carcinoma SGC-7901 cells. Inhibition of proliferation was detected with thiazolyl blue assay, and apoptosis was detected with fluorescence microscopy, transmission electron microscopy, and flow cytometry. The mechanisms were studied by measurement of caspase-3 and caspase-8 activities and Bax and Bcl2 mRNA expression. The thiazolyl blue assay showed that SGC-7901 cell viability and proliferation were inhibited significantly by E. esula extract in a time- and concentration-dependent manner. Fluorescence microscopy revealed that the cell nuclei showed the characteristic changes of apoptosis, such as uneven staining and chromatin marginalization. Some key features of apoptosis were also observed under transmission electron microscopy, which included cellular shrinkage and the foaming or bubbling phenomenon. When the cells were analyzed by flow cytometry, a sub-G1 peak could be seen clearly. Spectrophotometric assay of caspase-3 and caspase-8 activities in the treated cells showed an approximately two-fold increase. Reverse transcription polymerase chain reaction showed that Bax mRNA expression was upregulated, while Bcl2 mRNA expression was downregulated. E. esula extract inhibited proliferation and induced apoptosis in SGC-7901 cells, in a caspase-dependent manner, involving upregulation of Bax and downregulation of Bcl2.

Knockdown of Radixin Suppresses Gastric Cancer Metastasis In Vitro by Up-Regulation of E-Cadherin via NF-κB/Snail Pathway

Background/Aims: Radixin has recently been shown to correlate with the metastasis of gastric cancer, but the pathogenesis is elusive. Adhesion proteins contribute to the regulation of metastasis, and thus this study sought to investigate the role of radixin in the migration, invasion and adhesion of gastric cancer cells, as well as its interaction with adhesion proteins in vitro. Methods: Radixin stable knockdown human gastric carcinoma SGC-7901 cells were constructed. Alterations in the migration, invasion and adhesion ability were examined by matrigel-coated plate and transwell assays. The expression pattern of adhesion proteins, including E-cadherin, β-catenin and claudin-1, was determined by quantitative real-time PCR and western blot. Possible involvement of NF-κB/snail pathway was also evaluated. Results: Stable knockdown of radixin significantly suppressed migration and invasion, but enhanced adhesion in SGC-7901 cells. The expression of E-cadherin was manifestly increased in radixin knockdown cells, whereas the expression of β-catenin and claudin-1 was unchanged. The nuclear exclusion of NF-κB followed by conspicuous reduction of snail expression was involved in the regulation of E-cadherin expression. Conclusions: Radixin knockdown suppresses the metastasis of SGC-7901 cells in vitro by up-regulation of E-cadherin. The NF-κB/snail pathway contributes to the regulation of E-cadherin in response to depletion of radixin.

Chelidonine induces mitotic slippage and apoptotic-like death in SGC-7901 human gastric carcinoma cells.

The aim of the present study was to investigate the effect of chelidonine on mitotic slippage and apoptotic-like death in SGC-7901 human gastric cancer cells. The MTT assay was performed to detect the antiproliferative effect of chelidonine. Following treatment with chelidonine (10 µmol/l), the ultrastructure changes in SGC-7901, MCF-7 and HepG2 cells were observed by transmission electron microscopy. The effects of chelidonine on G2/M phase arrest and apoptosis of SGC-7901 cells were determined by flow cytometry. Indirect immunofluorescence assay and laser scanning confocal microscopy (LSCM) were used to detect the phosphorylation level of histone H3 (Ser10) and microtubule formation was detected using LSCM following immunofluorescent labeling. Subsequent to treatment with chelidonine (10 µmol/l), expression levels of mitotic slippage-associated proteins, including BUB1 mitotic checkpoint serine/threonine kinase B (BubR1), cyclin-dependent kinase 1 (Cdk1) and cyclin B1, and apoptosis-associated protein, caspase-3 were examined by western blotting at 24, 48 and 72 h. The half maximal inhibitory concentration of chelidonine was 23.13 µmol/l over 48 h and chelidonine induced G2/M phase arrest of cells. The phosphorylation of histone H3 at Ser10 was significantly increased following treatment with chelidonine for 24 h, indicating that chelidonine arrested the SGC-7901 cells in the M phase. Chelidonine inhibited microtubule polymerization, destroyed microtubule structures and induced cell cycle arrest in the M phase. Giant cells were observed with multiple micronuclei of varying sizes, which indicated that following a prolonged arrest in the M phase, the cells underwent mitotic catastrophe. Western blotting demonstrated that the protein expression levels of BubR1, cyclin B1 and Cdk1 decreased significantly between 48 and 72 h. Low expression levels of BubR1 and inactivation of the cyclin B1-Cdk1 complex results in the cells being arrested at mitosis and leads to mitotic slippage. In addition, apoptotic morphological changes in multinucleated cells were observed, the apoptosis rates increased gradually with administration of chelidonine in a time-dependent manner and the protein levels of caspase-3 increased significantly between 24 and 72 h. Thus, chelidonine induces mitotic slippage, and apoptotic-like death occurs in SGC-7901 cells undergoing mitotic catastrophe. Gastric cancer is a common malignancy, and ranks second in overall cancer-associated mortalities worldwide. The present study demonstrated that chelidonine induces M phase arrest and mitotic slippage of SGC-7901 human gastric carcinoma cells via downregulating the expression of BubR1, Cdk1 and cyclin B1 proteins. With the prolongation of chelidonine treatment, the giant cells with multiple micronuclei underwent mitotic slippage and were maintained in the G1 phase and did not survive. A number of multinucleated cells underwent apoptosis via a caspase-dependent signaling pathway. The current study proposes that chelidonine induces mitotic slippage and apoptotic-like death of SGC-7901 cells.