Human Gastric Cell Line SGC-7901 Research Articles

Characterization of a Flavonoid 3'/5'/7-O-Methyltransferase from Citrus reticulata and Evaluation of the In Vitro Cytotoxicity of Its Methylated Products.

O-methylation of flavonoids is an important modification reaction that occurs in plants. O-methylation contributes to the structural diversity of flavonoids, which have several biological and pharmacological functions. In this study, an O-methyltransferase gene (CrOMT2) was isolated from the fruit peel of Citrus reticulata, which encoding a multifunctional O-methyltransferase and could effectively catalyze the methylation of 3’-, 5’-, and 7-OH of flavonoids with vicinal hydroxyl substitutions. Substrate preference assays indicated that this recombinant enzyme favored polymethoxylated flavones (PMF)-type substrates in vitro, thereby providing biochemical evidence for the potential role of the enzyme in plants. Additionally, the cytotoxicity of the methylated products from the enzymatic catalytic reaction was evaluated in vitro using human gastric cell lines SGC-7901 and BGC-823. The results showed that the in vitro cytotoxicity of the flavonoids with the unsaturated C2-C3 bond was increased after being methylated at position 3’. These combined results provide biochemical insight regarding CrOMT2 in vitro and indicate the in vitro cytotoxicity of the products methylated by its catalytic reaction.

Recombinant Adenovirus KGHV500 and CIK Cells Codeliver Anti-p21-Ras scFv for the Treatment of Gastric Cancer with Wild-Type Ras Overexpression

The development of gastric cancer is frequently related to the overexpression of wild-type p21 proteins, but it is rarely related to mutated Ras proteins. We previously constructed a broad-spectrum anti-p21-Ras single-chain variable fragment antibody (scFv), which was carried by the oncolytic adenovirus KGHV500. Here we explored the antitumor effects of this recombinant oncolytic adenovirus carried by cytokine-induced killer (CIK) cells on human gastric SGC7901 cells that overexpress wild-type Ras. The MTT assay, scratch test, Transwell assay, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay were performed in vitro to investigate the proliferation, migration, invasiveness, and cell apoptosis rate, respectively, of the human gastric cell line SGC7901 treated with KGHV500 adenovirus. Then, the tumor-targeting ability and systemic safety of KGHV500 adenovirus delivered by CIK cells were explored in vivo. We found that KGHV500 adenovirus could significantly inhibit proliferation, migration, and invasiveness and promote cell apoptosis in SGC7901 cells in vitro. In vivo studies showed that CIK cells could successfully deliver KGHV500 adenovirus to the tumor site; the two vectors synergistically killed tumor cells, and the treatment was relatively safe for normal tissues. In conclusion, this therapeutic strategy of recombinant adenovirus KGHV500 delivered by CIK cells offers a positive prospect for the targeted therapy of Ras-related cancers.

CLIC1 Promotes the Progression of Gastric Cancer by Regulating the MAPK/AKT Pathways

Background/Aims: Chloride intracellular channel 1 (CLIC1), which is a member of the chloride channel protein family, is associated with various human tumors. Recent studies have shown that CLIC1 is involved in the occurrence and development of gastric cancer (GC). However, the exact mechanism remains unclear in GC. Methods: Effects of CLIC1 on the progression of GC in vivo and in vitro and the potential underlying mechanisms have been investigated by analysing 54 patients with GC, as well as human gastric cell lines SGC-7901 and MGC-803, utilizing proteomics, RT-PCR, Western blotting, flow cytometry, Cell invasion and migration assays and xenograft tumor models. Results: Our study shows that CLIC1 knockdown by targeted-siRNA markedly inhibits GC cell invasion and migration and induces apoptosis in vitro. In total, 54 differentially expressed proteins were identified in GC cells SGC-7901 after CLIC1 silencing by isobaric tags for relative isotope labeled and absolute quantitation (iTRAQ) technology, including integrin α1 (ITGα1) and ITGα3. The expression levels of ITGα3, ITGαv, ITGβ1 and Bcl-2 mRNA and protein were decreased significantly in GC cells after CLIC1 knockdown; ITGα1 and Fas were upregulated, but the level of survivin was not significantly different. GC growth and metabolism were decreased in vivo after CLIC1 silencing, but apoptosis was markedly increased. Further study showed that the expression levels of ITGα3, ITGαv and ITGβ1, as well as AKT-phosphorylation, ERK-phosphorylation and p38-phosphorylation, were reduced in vivo after CLIC1 knockdown, while ITGα1 was upregulated. Conclusions: We speculate that CLIC1 may play an important role in the progression of GC, and its mechanism may be related to the regulation of integrin family proteins, which leads to the sequential regulation of the PI3K/AKT, MAPK/ERK and MAPK/p38 pathways.

Hypoxia regulates CD44 expression via hypoxia-inducible factor-1α in human gastric cancer cells.

Hypoxia induces proliferation and invasion in cancer cells via hypoxia-inducible factor (HIF)-1α. The cell adhesion molecule cluster of differentiation (CD) 44 has been associated with increased cell invasion and metastasis. Whether hypoxia regulates the expression of CD44 in gastric cancer cells remains to be established. In the current study, the effects of hypoxia on HIF-1α and CD44 expression levels in human gastric cell lines SGC-7901 and BGC-823 were evaluated. The cells were cultured in 1% O2 for 1 week and then treated with 20 nM rapamycin for 72 h. Cell viability was evaluated using the Cell Counting kit-8 assay, and cell invasion was detected by the Transwell invasion assay. The protein and messenger (m) RNA expression levels of HIF-1α and CD44 were detected using western blotting and reverse transcription-quantitative polymerase chain reaction, respectively. The results revealed that cell viability and invasion increased under hypoxic conditions, but decreased following rapamycin treatment in SGC-7901 and BGC-823 cells. Hypoxia also increased the protein and mRNA expression levels of HIF-1α and CD44 in these two cell lines. However, this hypoxia-induced increase in HIF-1α and CD44 protein and mRNA expression levels was inhibited by rapamycin. These findings suggest that hypoxia induced the proliferation and invasion of SGC-7901 and BGC-823 cells. Furthermore, CD44 expression levels were potentially associated with HIF-1α expression levels. Therefore, in gastric cancer cells, hypoxia may regulate CD44 expression via HIF-1α in order to promote cell proliferation and invasion.

Effect of Tissue Factor on Invasion Inhibition and Apoptosis Inducing Effect of Oxaliplatin in Human Gastric Cancer Cell

Tissue factor (TF) is expressed abnormally in certain types of tumor cells, closely related to invasion and metastasis. The aim of this study was to construct a human gastric cancer cell line SGC7901 stably-transfected with human TF, and observe effects on oxaliplatin-dependent inhibition of invasion and the apoptosis induction. The target gene TF was obtained from human placenta by nested PCR and introduced into the human gastric cell line SGC7901 through transfection mediated by lipofectamine. Stably-transfected cells were screened using G418. Examples successfully transfected with TF-pcDNA3 recombinant (experimental group), and empty vector pcDNA3 (control group) were incubated with oxaliplatin. Transwell chambers were used to show change in invasive ability. Caspase-3 activity was detected using a colorimetric method and annexin-V/PI double- staining was applied to detect apoptosis. We generated the human gastric cancer cell line SGC7901/TF successfully, expressing TF stably and efficiently. Compared with the control group, invasion increased, whereas caspase-3 activity and apoptosis rate were decreased in the experimental group. TF can enhance the invasive capacity of gastric cancer cells in vitro. Its increased expression may reduce invasion inhibition and apoptosis-inducing effects of oxaliplatin and therefore may warrant targeting for improved chemotherapy.

Effect of allitridi on inducing mitotic arrest in human gastric cell line SGC-7901 and its possible mechanism

Objective To learn the effect of allitridi on inducing mitotic arrest in human gastric cell line SGC-7901 and its possible mechanisms.

Clinical and experimental study of oxaliplatin in treating human gastric carcinoma.

To evaluate the therapeutic effectiveness of oxaliplatin on human gastric carcinoma and to explore its mechanisms. Twenty-two cases of stage IV gastric carcinoma received 4-6 (mean 4.6) cycles of first line combined chemotherapy with oxaliplatin (oxaliplatin 85 mg/m(2), iv, gtt, 1 h, d 1; leukovorin 200 mg/m(2), iv, gtt, 1 h, d 1 and d 2; 5-FU 300 mg/m(2),iv, d 1 and d 2, 5-FU, continuous iv, gtt, 48 h; 1 cycle/2 wk). Response rate, progression-free survival (PFS), total survival time, toxic side effects were evaluated. The inhibitory effect of oxaliplatin on human gastric cell line SGC-7901 was detected and IC(50) was calculated by MTT. Transmission electron microscopy, flow cytometry and TUNEL were performed to evaluate the apoptosis of cell line induced by the drug. The expression of Caspase-3 m-RNA was detected by RT-PCR. AC-DEVD-CHO, a Caspase-3 specific inhibitor, was used to elucidate the role of activated Caspase-3 in the process of apoptosis induced by oxaliplatin. Total response (complete and partial) occurred in 9 (40.9%) patients. Mean PFS was 4.2 mo and mean total survival time was 7.2 mo. Cumulative neurotoxicity (all grade I-II), vomiting and diarrhea, myelosuppression appeared in 93.5%, 20%, 32.9% patients, respectively. IC(50) was calculated to be 0.71 mg/L by MTT assay. A maximal inhibitory rate reached 85.3%. Apoptosis index was elevated after incubated with 1 mmol/L oxaliplatin for 30 min, but without statistic significance (P>0.05). However it could be detected at a much higher degree both by flowcytometry and by TUNEL with a statistical significance (68.47+/-7.92% and 8.23+/-2.67%, respectively, P<0.05) after incubated with 1 mmol/L oxaliplatin for 2 d. By means of RT-PCR, we detected an enhancement of Caspase-3 m-RNA expression induced by oxaliplatin which was also in positive correlation with the apoptotic level. AC-DEVD-CHO, a Caspase-3 specific inhibitor, could significantly inhibit and delay apoptosis induced by oxaliplatin. Oxaliplatin is effective and well-tolerated in patients with advanced gastric carcinoma. Oxaliplatin could significantly inhibit the growth of human gastric cell line SGC-7901. The induction of Caspase-3 m-RNA expression, activation of Caspase-3 and promotion of apoptosis may be some of the therapeutic mechanisms of oxaliplatin on gastric carcinoma. Annexin-V-fluorescein labeling flow cytometry is much more sensitive than TUNEL in detecting early stage apoptosis.

Clinical efficacy and mechanism of oxaliplatin in treating human gastric carcinoma

AIM: To evaluate the therapeutic effect of oxaliplatin on human gastric carcinoma and to explore the mechanisms. METHODS: 22 cases of stage gastric carcinoma patients received 4-6 (mean 4.6) cycles of first line combined chemotherapy with oxaliplatin (oxaliplatin 85 mg/m 2 , ivgtt, 1 h, d 1; leukovorin 200 mg/m 2 , iv, gtt, 1 h, d 1-5; 5-FU 300 mg/m 2 ,iv, d 1-2; 5-FU, continuously iv, gtt, 48 h; 1 cycle/2w). Response rate, progression-free survival (PFS), total survival time, toxic side effects were evaluated. The inhibitory effect of oxaliplatin on human gastric cell line SGC-7901 was calculated by MTT and IC50 was measured. Flow cytometry and TUNEL were applied to evaluate the apoptosis of cell line induced by the drug. The expression of caspase-3 mRNA was detected by RT-PCR. RESULTS: Total response (complete and partial) occurred in 9 (40.9 %) patients. Mean PFS was 4.2 months and mean total survival time was 7.2 months. Cumulative neurotoxicity (all grade - ), vomiting and diarrhea, myelosuppression appeared in 93.5 %, 20 %, 32.9 % of the patients, respectively. Apoptosis index was elevated after incubating with 1 mmol/L oxaliplatin for 30 min, but without statistic significance (P >0.05), but was much higher both by flowcytometry and TUNEL with statistical significance (P <0.05) after incubating with 1 mmol/L oxaliplatin for 2 days. Caspase-3 mRNA expression was elevated in oxaliplatin treated cells and correlated with apoptosis induced by the drug. CONCLUSION: Oxaliplatin is effective and well-tolerated on human advanced gastric carcinoma. Oxaliplatin could significantly inhibit the growth of human gastric cell line SGC-7901, inducing caspase-3 mRNA expression and cell apoptosis

Molecule action mechanisms of NM-3 on human gastric cancer SGC-7901 cellsin vivoorin vitro

To study the molecule action mechanisms of NM-3 on the growth of human gastric cancer SGC-7901 cells in vivo or in vitro. SGC-7901 from human non-differentiated gastric cancer cell line was cultured with NM-3 at 100 mg/ml for 24 h. We observed its inhibitory rate and the density of micro-vascular growth in grafted mice with human gastric cancer SGC-7901. The apoptosis of human gastric cancer SGC-7901 was revealed in NM-3 treatment group by using terminal deoxynucleotidyl transferase-mediated deoxy-uridine triphosphate-fluorescene nick end labeling (TUNEL) method and flow cytometry analysis. The growth of SGC-7901 cells was markedly inhibited compared with control growp, which was smaller than that in normal saline control group (4.17 g+/-0.22 g vs 9.45 g+/-1.38 g, P<0.01). The level of apoptosis of human gastric cell line SGC-7901 was obviously increased in NM-3 treatment group at 1 mg.L(-1) for 24 h. NM-3 inducing apoptotic index in NM-3 plus carboplatin group was 3.5 times that of carboplatin control group (TUNEL: 27.98+/-6.12% vs 12.94+/-2.12%, FACScan: 26.86+/-5.69% vs 11.86+/-1.09%, P<0.01). Western blot analysis showed that the apoptotic index of human gastric cancer was elevated for 12, 24 and 36 h with an evident time-effect relationship in groups at 100 mg.L(-1). NM-3 enhanced the inhibitive effects and sensitivity of chemotherapy for human gastric cancer in nude mice. These results suggested that NM-3 played a key inhibitive role in the growth of grafted human gastric cancer in nude mice. NM-3 can inhibit the growth of human gastric cancer cell line SGC-7901, and enhance the sensitivity of carboplatin on SGC-7901 and induced its apoptosis.