Lobaplatin inhibits growth of gastric cancer cells by inducing apoptosis

AIM: To assess the anti-cancer effect of lobaplatin on human gastric cancer cells, and to explore the underlying molecular mechanisms.METHODS: The human gastric cancer cell lines MKN-28, AGS and MKN-45 were used. The cytotoxicity of lobaplatin was detected using an MTS cell proliferation assay. Flow cytometry was used to detect cell apoptosis using Annexin V-FITC Apoptosis Detection Kit. The expression of apoptosis-regulated genes was examined at the protein level using Western blot.RESULTS: Lobaplatin inhibited the proliferation of human gastric cancer cells and induced apoptosis, which may be associated with the up-regulation of Bax expression, poly(ADP-ribose) polymerase (PARP) cleavage, p53 expression and the reduction of Bcl-2 expression.CONCLUSION: The cytotoxicity of lobaplatin may be due to its ability of inducing apoptosis of gastric cancer cells, which would support the potential use of lobaplatin for the therapy of gastric cancer.     

Effect of silencing Bcl-2 expression by small interfering RNA on radiosensitivity of gastric cancer BGC823 cells

ObjectiveTo explore the influence of silencing Bcl-2 expression by small interfering RNA (siRNA) on Bcl-2 protein expression, cell apoptosis rate and radiosensitivity of gastric cancer BGC823 cells.MethodssiRNA segment for Bcl-2 gene was designed and synthesized, then was induced into gastric cancer BGC 823 cells by liposome transfection. Bcl-2 protein expression was detected by Western Blotting. After X radiation, flow cytometry and clone forming assay were used to determine the effects of RNA interference on BGC823 cell apoptosis rate and radiosensitivity.ResultAfter the transfection of Bcl-2 siRNA, the positive expression rate of Bcl-2 protein in BGC823 cells was (35.45±2.35)%. Compared with the control group and negative siRNA transfection group, the rate was significantly decreased (P<0.01). The apoptosis rate of BGC823-RNAi cell was (10.81±0.91)%, which was significantly higher than the control group and negative siRNA transfection group (P<0.01). After 48h X radiation, the apoptosis rate of BGC823-RNAi was (28.91±1.40)%, which was significantly higher than the control group and the group without radiation (P<0.01). During clone forming assay D₀, D_q and SF₂ values in Bcl-2 siRNA1 transfection group were all lower than those in the control group. The radiosensitivity ratio was 1.28 (the ratio of D₀) and 1.60 (the ratio of D_q).ConclusionsSpecific siRNA of Bcl-2 gene can effectively inhibit the expression of Bcl-2 gene, enhance the radiosensitivity and apoptosis of gastric cancer BGC823 cells, having good clinical application perspective.     

p53 upregulated by HIF-1α promotes gastric mucosal epithelial cells apoptosis in portal hypertensive gastropathy

BackgroundPortal hypertensive gastropathy (PHG) is a serious complication of liver cirrhosis and a potential cause of gastrointestinal bleeding. Mucosal apoptosis is an essential pathological feature of PHG. However, whether HIF-1α and p53 are involved in mucosal apoptosis and whether HIF-1α induces PHG by mediating p53 remains unclear.MethodsGastric mucosal injury and apoptosis were examined in PHG patients and animal models. The mechanisms of HIF-1α- and p53-mediated apoptosis were analyzed. The GES-1 cell line was used to elucidate the underlying mechanisms using siRNA knockdown of HIF-1α and p53 in a hypoxic environment in vitro.ResultsEpithelial apoptosis, HIF-1α, and p53 were markedly induced in the gastric mucosa of PHG. Apoptosis was attenuated in mice with HIF-1α- and p53-specific inhibitors. Apoptotic signaling factors were markedly induced in the gastric mucosa of PHG. Inhibition of p53 demonstrably attenuated the mucosal apoptosis; however, it did not affect HIF-1α expression. Conversely, targeted deletion of HIF-1α significantly inhibited p53 expression and attenuated the injury and p53-mediated apoptosis. Bax and Bcl-2 expression can be upregulated and downregulated by p53, respectively, to increasecleaved caspase-3 expression, which can be regulated by HIF-1α.ConclusionsThese results indicate that HIF-1α regulates the p53-induced mucosal epithelial apoptotic signaling pathway and that HIF-1α and p53 are potential therapeutic targets for PHG.     

CD74 and macrophage migration inhibitory factor as therapeutic targets in gastric cancer

AIM: To investigate the relationship and molecular features of CD74/macrophage migration inhibitory factor (MIF)/Toll-like receptor 4 (TLR4) in gastric cancer.METHODS: CD74, MIF and TLR4 expression in the paraffin-embedded sections of gastric cancer from 120 patients were detected by immunohistochemical staining. Knock down of CD74 expression in gastric cancer cell line MKN-45 was performed by lentivirus transduction and detected by Western blotting. MKN-45 cell proliferation assay under the stimulants was measured by the cell counting kit 8 (CCK8) assay and MIF concentration in the culture medium was detected by enzyme-linked immunosorbent assay. Surface staining of CD74 in the MKN-45 cell line under the stimulation of lipopolysaccharide (LPS) was measured by flow cytometry. MIF, CD74 and TLR4 co-localization in the MKN-45 cell line was performed by the immunoprecipitation.RESULTS: CD74, MIF and TLR4 were found to be expressed in gastric cancer and increased significantly in the advanced stage, and were also associated with lymph node metastasis. Correlation analysis revealed that CD74 was positively correlated with MIF (r = 0.2367, P < 0.01) and both proteins were also associated with TLR4 (r = 0.4414, r = 0.5001, respectively, P < 0.01). LPS can significantly promote MKN-45 cell proliferation (3.027 ± 0.388 vs 4.201 ± 0.092, P < 0.05), induce MIF production (54.333 ± 2.906 pg/mL vs 29.667 ± 3.180 pg/mL, P < 0.01) and cell surface expression of CD74 (75.6% ± 4.046% vs 9.4% ± 0.964%, P < 0.01) at LPS concentration of 1 μg/mL compared to medium control. Knockdown of CD74 or using anti-CD74 and MIF antagonist ISO-1 significantly reduced LPS-induced MKN-45 cell proliferation (4.201 ± 0.092 vs 3.337 ± 0.087, 4.534 ± 0.222 vs 3.368 ± 0.290, 4.058 ± 0.292 vs 2.934 ± 0.197, respectively, P < 0.01). MIF, CD74 and TLR4 could co-localize in the MKN-45 cell line.CONCLUSION: Upregulation of MIF, CD74 and TLR4 are associated with increasing clinical stage and provide an opportunity as novel gastric cancer chemoprevention and/or treatment strategy.     

Induction of apoptosis by arsenic trioxide and hydroxy camptothecin in gastriccancer cells in vitro

AIM To study the effects of arsenic trioxide and HCPT on different degrees of differentiated gastric cancer cells (SGC-7901, MKN-45, MKN-28)with respect to both cytotoxicity and induction of apoptosis in vitro. ~ODS The cytotoxicity of As2O3 and HCPT on gastric cancer cells was determined by MTTassay. Morphologic changes of apoptosis of gastric cancer cells were observed by light microscopy and transmission electron microscopy. Apoptosis and cell cycle changes of gastric cancer cells induced by HCPT and As2O3 were investigated by TUNEL method and flow cytometry. RESULTS As2O3 and HCPT had remarkable cytotoxic effects on different degrees of differentiated gastric cancer cells. The IC50 of As2O3 on well differentiated gastric cancer cell MKN-28, moderately differentiated gastric cancer cell SGC-7901, and poorly differentiated gastric cancer cell MKN-28 were 8. 91 μmol/L, 10. 57 μmol/L, and 11.65 μmol/L, respectively. The IC50 of HCPT on MKN-28, SGC-7901, and MKN-45 were 9. 35 rg/L, 10. 21 rg/L, and 12. 63 mg/L respectively after 48 h treatment. After 12 h of exposure to both drugs, gastric cancer cells exhibited morphologic features of apoptosis, including cell shrinkage, nuclear condensation,and formation of apoptotic bodies. A typical subdiploid peak before G0/G1 phase was observed by flow cytometry. The apoptotic rates of SGC7901, MKN-45, and MKN-28 were 13. 84%, 22.52%, and 9. 68%, respectively after 48 h exposure to 10 μmol/L As2O3. The apoptotic rates of SGC-7901, MKN-45, and MKN-28 were 21.88%, 12.35%, and 30. 26%, respectively after 48 h exposure to 10 mg/L HCPT. The apoptotic indice were 7% - 15% as assessed by TUNEL method. The effect of As2O3 on SGC-7901 showed remarkable cell cycle specificity, which induced cell death in G1 phase, and blocked G2/M phase. HCPT also showed a remarkable cell cycle specificity, by inducing cell death and apoptosis in G1 phase and arrest of proliferation at S phase. CONCLUSION AS2O3 and HCPT exhibit significant cytotoxicity on gastric cancer cells by induction of apoptosis. As2O3 and HCPT might have a promising prospect in the treatment of gastric cancer, which needs to be further studied.     

Synergistic effect of oxymatrine and angiogenesis inhibitor NM-3 on modulating apoptosis in human gastric cancer cells

AIM: To investigate the synergistic effect of oxymatrine(OM) and angiogenesis inhibitor NM-3 on modulatingapoptosis in human gastric cancer cell lines SGC-7901,MKN-45, MKN-74. METHODS: Human gastric cancer lines SGC-7901,MKN-45, MKN-74 were treated with OM in the absenceand presence of NM-3. The inhibitory rates weredetected by MTT assay. Synergistic effect of OM andNM-3 on the growth of survivin, bcl-2, bax and p53 inSGC-7901 cells were examined by semiquantitative RT-PCR and Western blotting, and their growth inhibitoryeffects were also observed on SGC-7901 tumor xenograftin nude mice.RESULTS: OM combined with NM-3 exhibited asynergistic inhibitory effect on the growth of SGC-7901,MKN-45 and MKN-74 cells in a time-dependent manner.Twenty-four hours after treatment with OM, NM-3 aloneand their combination, mRNA expression of survivin andbcl-2 in SGC-7901 cells decreased, p53 mRNA expressionincreased. OM (4 g/L) combined with NM-3 significantlyincreased the expression of p53 mRNA and decreasedthe expression of survivin and bcl-2 compared witheither agent alone (193% ± 34% vs 129% ± 12%;44% ± 18% vs 92% ± 18%; 36 ± 17% vs 93% ± 23%,P < 0.05). Western blotting showed that the synergisticeffect of OM and NM-3 on protein translation of survivin,bcl-2 and p 53 was in accordance with their mRNAs.Furthermore, OM/NM-3 combination obviously exhibitedantitumor growth effect in xenografted human gastriccancer cells SGC-7901 compared with either agent alone.CONCLUSION: OM combined with NM-3 has synergisticinhibitory effects on human gastric cancer cells in vitro and can suppress the growth of xenografted human gastric cancer cells SGC-7901 in vivo.     

P115 promotes growth of gastric cancer through interaction with macrophage migration inhibitory factor

AIM:To investigate the role of P115 in the proliferation of gastric cancer cells and the mechanism involved.METHODS:The RNA and protein level of P115 and macrophage migration inhibitory factor(MIF)in gastric cancer and normal gastric tissue/cells were measured and the effect of P115 on cell proliferation was assessed.The role of P115 in cell cycle checkpoints was investigated and the related proteins and signaling pathways,such as cyclin D1,Mcm2,p53,PCNA as well as the MAPK signaling pathway were determined.The interaction between P115 and MIF and the effect of P115 on MIF secretion were examined.The data were analyzed via one-way ANOVA comparisons between groups and P<0.05 was considered significant.RESULTS:P115 and MIF were both specifically expressed in gastric cancer tissues compared with normal gastric mucosa(both P<0.01).The mRNA and protein levels of P115 and MIF in gastric cancer cell lines MKN-28 and BGC-823 were higher than in the human gastric epithelial cell line GES-1(both P<0.01).In MKN-28 and BGC-823 cell lines,P115 promoted cell proliferation and G0-G1to S phase transition.In addition,several cell cycle-related regulators,including cyclin D1,Mcm2,PCNA,pERK1/2 and p53 were up-regulated by P115.Furthermore,the interaction between P115 and MIF was confirmed by co-immunoprecipitation assay.ELISA showed that P115 stimulated the secretion of MIF into the culture supernatant(P<0.01)and the compensative expression of MIF in cells was observed by Western blotting.CONCLUSION:P115 promotes proliferation of gastric cancer cells through an interaction with MIF.     

Effect of RNA Interference Inhibiting the Expression of the FUBP1 Gene on Biological Function of Gastric Cancer Cell Line SGC7901

Background: The research aimed to observe the effect of gene silencing on the proliferation, migration, cell cycle, apoptosis, and other biological functions of human gastric cancer cells with RNA interference inhibiting the expression of the far upstream element-binding protein 1 (FUBP1) in the gastric cancer cell line SGC7901.Methods: The shRNA lentivirus vector of the target gene FUBP1 was constructed to transfect the gastric cancer cell line SGC7901. The qRT-PCR and western blot assays were used to detect the expression levels of FUBP1 mRNA and protein in the gastric cancer cells. The CCK-8 assay was used to detect the proliferation of gastric cancer cells. The cell scratch assay and the transwell assays were used to detect the migration of gastric cancer cells. Flow cytometry was used to detect cell cycle distribution and apoptosis.Results: The shRNA lentiviral vector of FUBP1 was successfully transfected into the gastric cancer cell line SGC7901, and could effectively reduce the expression of mRNA and protein of FUBP1. The silencing of FUBP1 could inhibit the gastric cancer cell proliferation and affect the distribution of the cell cycle, resulting in S-phase arrest and cell growth inhibition. However, FUBP1 silencing has no significant effect on cell apoptosis and migration.Conclusions: The expression of FUBP1 can be inhibited specifically and effectively by RNA interference technology, which can significantly affect the biological function of the gastric cancer cell line SGC7901.     

A novel molecular targeting compound as K-samII/FGF-R2 phosphorylation inhibitor, Ki23057, for Scirrhous gastric cancer

BACKGROUND & AIMS: Scirrhous gastric carcinoma carries the highest mortality of all gastric cancers. The poor prognosis is reported to be associated with K-samII amplification, which encodes fibroblast growth factor receptor type 2 (FGF-R2). Ki23057, a newly developed small molecule-acting K-samII/FGF-R2 autophosphorylation inhibitor, is a tyrosine kinase inhibitor that competes with adenosine triphosphate for the binding site. The aim of the current study is to clarify the possibility of molecular target therapy with Ki23057 for treating scirrhous gastric cancer. METHODS: Five human gastric cancer cell lines were used. OCUM-2MD3 and OCUM-8 were derived from scirrhous carcinomas. MKN-7, MKN-45, and MKN-74 cells were derived from nonscirrhous carcinomas. In vitro effects of Ki23057 on cell growth were determined by calculating the number of cancer cells. The influences of Ki23057 on the mitogen-activated protein kinase and phosphatidylinositol 3 kinase signaling pathways and the apoptosis pathway in the gastric cancer cells were also examined. For in vivo experiments, the Ki23057 was administered orally to mouse models of peritoneal dissemination. RESULTS: K-samII amplification was found in OCUM-2MD3 and OCUM-8 cells but not in MKN-7, MKN-45, or MKN-74 cells. Ki23057 significantly inhibited the proliferation of scirrhous cancer cells but not nonscirrhous gastric carcinoma cells. Ki23057 decreased phosphorylation of K-samII/FGF-R2, extracellular signal-regulated kinase, and Akt and increased apoptosis in scirrhous cancer lines. The oral Ki23057 administration significantly (P < .001) prolonged survival of mice with peritoneal dissemination following injection of OCUM-2MD3 scirrhous cancer cells. CONCLUSIONS: A novel K-samII/FGF-R2 phosphorylation inhibitor, Ki23057, appears therapeutically promising in scirrhous gastric carcinoma with K-samII amplification.     

Low-dose oxaliplatin enhances the antitumor efficacy of paclitaxel in human gastric cancer cell lines

BACKGROUND: The enhanced antitumor effect of paclitaxel when used with oxaliplatin in gastric cancer is reported, however the underlying biological mechanism is unknown. METHODS: We tested the cytotoxic activity, apoptosis, and mitotic catastrophe of paclitaxel and oxaliplatin in MKN-28 and MKN-45 gastric cancer cell lines. The modulation of survivin expression was determined by Western blotting. RESULTS: WST-1 assay indicated that paclitaxel plus oxaliplatin showed better cytotoxicity than paclitaxel alone, even when low concentrations of oxaliplatin were used. Flow cytometry analysis revealed significantly greater increases in apoptotic cells after treatment with paclitaxel followed by low-dose oxaliplatin (1 microM) than after any single-reagent regimen in the MKN-45 cell line. In MKN-28, a difference existed only between combination treatment and oxaliplatin treatment. Morphologic examination showed that the cells undergoing mitotic catastrophe were highest in the combination groups in the both cell lines. Downregulation of survivin expression was found by Western blotting with treatment by paclitaxel, oxaliplatin, or their combination. CONCLUSION: Our findings suggest that the mechanism of enhanced cytotoxicity might be through enhanced mitotic catastrophe and apoptosis, which is possibly due to chemotherapy-induced downregulation of surviving. The combination of paclitaxel and low-dose oxaliplatin should be incorporated into the design of a clinical trial.     

15-PGDH抑制剂对人胃癌细胞生长和COX-2表达的影响

背景：15-羟基前列腺素脱氧酶（15-PGDH）是前列腺素生物降解的关键酶,对环氧合酶-2（COX-2）具有生理性拮抗作用,其表达减少和活性降低与多种恶性肿瘤的发生、发展有关。目的：观察15-PGDH选择性抑制剂Cayl0397对人胃癌细胞生长、凋亡和COX-2表达的影响,探讨15．PGDH与COX-2在胃癌中的可能关系以及15-PGDH的抗肿瘤机制。方法：以不同浓度Cay10397干预人胃癌细胞株MKN-28,MTr实验和流式细胞分析检测细胞生长和凋亡情况;RT—PCR和蛋白质印迹法检测凋亡相关基因survivin、bax、bcl—xLmRNA表达以及15-PGDH、COX-2mRNA和蛋白表达。结果：Cayl0397在浓度大于2．5μmol／L、作用时间超过48h的条件下能促进MKN-28细胞增殖（P〈0．05）,但其对MKN-28细胞凋亡无明显影响。经5—20μmol／LCayl0397作用72h的MKN-28细胞,survivin、bcl-xLmRNA表达显著升高（P〈0．05）,baxmRNA以及15-PGDHmRNA和蛋白表达显著降低（P〈0．05）,COX-2mRNA和蛋白表达无明显变化。结论：抑制15-PGDH表达可促进人胃癌细胞增殖,但对COX-2表达无明显影响。15-PGDH可能通过下调抗凋亡基因survivin、bcl-xL表达、上调促凋亡基因bax表达而诱导人胃癌细胞凋亡。     

Antiproliferative and apoptotic effects of Phyla nodiflora extracts on human breast cancer cell line

IntroductionCancer is a disease of gene disorder that occurs in the normal processes of cell division. Undesirable side effects of chemotherapy and surgery have triggered the search of new compounds from plant to fight cancer because they are relatively safer than synthetic drugs. Apoptosis is a process of internally programmed cell death, which is initiated by intrinsic or extrinsic signals. It plays important roles in cancer development and treatment, thus the ability of bioactive compounds to increase the sensitivity of cancerous cells towards cellular damage and activate the apoptotic response is the most desirable. Phylanodiflora has been used as folk medicine for various ailments. It is known to have various biological activities such as antioxidant, antimicrobial, antitumor, anti-inflammatory, antidiabetic, and hepatoprotective and antimelanogenesis effects but their underlying molecular events are largely unknown.ObjectiveTo study the antiproliferative and apoptosis activity of P.nodiflora in MCF7 cells.MethodsThe leaf and stem of this plant was extracted separately using methanol and ethyl acetate. The free radical scavenging activity of the plant extracts was determined using DPPH antioxidant assay, while the proliferation assay was performed using MTT method. DNA fragmentation induced by the plant extracts was evaluated through DNA extraction.Results & DiscussionCompared to stem extracts (1.2134 mg/ml and 0.9877 mg/ml for ethyl acetate and methanol respectively), both leaf extracts exhibited lower EC₅₀ values (0.4271 mg/ml and 0.6177 mg/ml for ethyl acetate and methanol respectively) which indicating higher antioxidant activity. MTT results showed that MCF7 cells were inhibited by all the extracts with IC₅₀ ranging from 90–120 μg/ml. DNA extracted from treated cells showed the formation of DNA laddering suggesting the occurrence of apoptosis.ConclusionThe results suggest that Phyla nodiflora extracts are capable of inhibiting cancer cell growth via apoptosis.     

HTRA1 gene expression in gastric epithelial cells

Objective:To explore HtrA1 gene expression aud its regulation in human gastric cancers.Methods:The HtrA1 mRNA levels were examined by QPCR analysis and coufirmed its expression with Northern blot analysis.The HtrA1 protein levels in all six gastric epithelial cell lines were investigated by Western blot analysis.Gene copy number was accessed and then sequenced the coding region from each mRNA in all six cell lines.The HtrA1 promoter region DNA methylation status was detected by using bisulfite sequeucing analysis.Effect of decitabine and TSA on HTRA1 expression in gastric cancer cell line was determined by RTPCR.Results:HIC analysis indicated that HtrA1 was highly expressed in normal epithelium,but dramatically down-regulated in gastric carcinoma tissues and variably expressed in tumor-adjacent tissues.HtrA1 gene expression was dramatically decreased in gastric carcinoma cells compared to nontumorigenic counterparts.The HtrA1 gene loss in any of the 4 breast cancer cell lines was not detected.Total 14 CpGs in this region were all methylated in gastric cancer cells,whereas two normal cells.GES-1 and HFI-145,were having several unmethylated cytosines in this region.HtrA1 showed as~Mr 44,000,Expression of HtrA1 protein was not observed in any of the four gastric caucer cell lines.BGC-823.MKN-45.SGC-7901and MKN-28.HtrA1 expression was observed in the HF1-145and GES-1 cell lines.Conclusions:The epigenetic silencing for HtrA1gene expression could provide a possible strategy for re-activating Htrt1 gene expression in gastric cancer cells.thus facilitating further investigation of HtrA1's role in chemotherapy.     

Effect of trans-retinoic acid and folic acid on apoptosis in human gastric cancer cell lines MKN-45 and MKN-28

Induction of apoptosis has been implicated as an anticarcinogentic mechanism of both folic acid and retinoic acid. The ability of retinoic acid or folic acid to induce gastric cancer cell apoptosis was investigated in the human gastric cancer cell lines MKN-45 and MKN-28, and DNA fragmentation was studied in situ by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling and DNA agarose gel electrophoresis. The rates of apoptosis in both the poorly differentiated MKN-45 and the well differentiated MKN-28 cell line were less than 5% after treatment with either retinoic or folic acid. Apoptosis may be induced by the administration of retinoic acid or folic acid, and the apoptosis indices of MKN-45 and MKN-28 cells were related to the doses of these drugs. The induction of gastric cancer cell apoptosis may play a role in the anticarcinogenetic effect of retinoic acid and folic acid, both of which are potential agents for the treatment of human gastric cancer. Received Sept. 16, 1997; accepted Mar. 17, 1998     

Gastric cancer cells induce human CD4^＋ Foxp3^＋ regulatory T cells through the production of TGF-β1

AIM: To elucidate the molecular and cellular features responsible for the increase of regulatory T cells (Tregs) in gastric cancer.METHODS: The frequencies of CD4⁺Foxp3⁺ Tregs and the level of transforming growth factor-β1 (TGF-β1) were analyzed from 56 patients with gastric cancer by flow cytometry and enzyme-linked immunosorbent assay respectively. Foxp3 gene expression was analyzed by real-time polymerase chain reaction. The gastric cancer microenvironment was modeled by establishing the co-culture of gastric cancer cell line, MGC-803, with sorting CD4⁺ T cells. The normal gastric mucosa cell line, GES-1, was used as the control. The production of TGF-β1 was detected in supernatant of MGC and GES-1. The carboxyfluorescein diacetatesuccinimidyl ester (CFSE) dilution assay was performed to evaluate the proliferation characteristics of induced Tregs. Neutralizing anti-TGF-β1 antibody was added to the co-culture system for neutralization experiments.RESULTS: The level of serum TGF-β1 in gastric cancer patients (15.1 ± 5.5 ng/mL) was significantly higher than that of the gender- and age-matched healthy controls (10.3 ± 3.4 ng/mL) (P < 0.05). Furthermore, the higher TGF-β1 level correlated with the increased population of CD4⁺Foxp3⁺ Tregs in advanced gastric cancer (r = 0.576, P < 0.05). A significant higher frequency of CD4⁺Foxp3⁺ Tregs was observed in PBMCs cultured with the supernatant of MGC than GES-1 (10.6% ± 0.6% vs 8.7% ± 0.7%, P < 0.05). Moreover, using the purified CD4⁺CD25^- T cells, we confirmed that the increased Tregs were mainly induced from the conversation of CD4⁺CD25^- naive T cells, and induced Tregs were functional and able to suppress the proliferation of effector T cells. Finally, we demonstrated that gastric cancer cells induced the increased CD4⁺Foxp3⁺ Tregs via producing TGF-β1. Gastric cancer cells upregulated the production of TGF-β1 and blockade of TGF-β1 partly abrogated Tregs phenotype.CONCLUSION: Gastric cancer cell can induce Tregs development via producing TGF-β1, by which the existence of cross-talk between the tumor and immune cells might regulate anti-tumor immune responses.     

Heat Shock Protein 27 Expression is Inversely Correlated with Atrophic Gastritis and Intraepithelial Neoplasia

Background

Intestinal-type gastric carcinomas progress through several sequential steps, including atrophic gastritis, intestinal metaplasia, dysplasia, and cancer.

Aim

We investigated heat shock protein 27 (HSP27) expression in gastric neoplasia and background gastric mucosa to assess its involvement in gastric carcinogenesis.

Methods

We used real-time quantitative polymerase chain reaction to examine HSP27 expression in gastric neoplasias and background gastric mucosae of 30 patients with intraepithelial neoplasias and in gastric mucosae of 30 patients without gastric neoplasia. Immunohistochemical staining was performed on 30 advanced gastric cancer tissues.

Results

HSP27 expression was negatively associated with atrophic gastritis. HSP27 expression in the background gastric mucosa of neoplasia-bearing patients was significantly lower than in the mucosa of those without gastric neoplasia. In tumor necrosis factor α-treated gastric cancer cells, HSP27 knockdown increased cell death and accumulation of the reactive oxygen species that link inflammation to cancer. Poorly differentiated tumors most frequently had high HSP27 levels. Dedifferentiation of cancer cells is associated with an epithelial–mesenchymal transition (EMT) signaling pathway. In gastric cancer MKN-1 cells, HSP27 knockdown upregulated E-cadherin and downregulated vimentin and smooth muscle actin, but this did not occur in MKN-74 cells.

Conclusion

HSP27 expression in gastric mucosae is inversely correlated with intraepithelial neoplasia, a probable precursor to gastric cancer, and HSP27 expression in cancer is positively correlated with poor differentiation.     

WASF3 Knockdown Sensitizes Gastric Cancer Cells to Oxaliplatin by Inhibiting ATG12-Mediated Autophagy

BackgroundGastric cancer is one of the most aggressive tumors, usually resulting in metastasis, and therapies for advanced gastric cancer remain limited. Drug resistance is the main reason for chemotherapeutic failure in gastric cancer. Wiskott-Aldrich syndrome protein family member 3 (WASF3) is required for invasion and metastasis of different cancers. However, there has been little study of WASF3 expression involvement in gastric cancer. In this study, we explored the role of WASF3 in the sensitivity of gastric cancer to oxaliplatin, and the underlying mechanisms.MethodsWe silenced WASF3 using WASF3-siRNA in MGC803 cells. Then, CCK-8, flow cytometry and transwell assay were performed to study the effect of WASF3 silencing on proliferation, migration, invasiveness and apoptosis of MGC803 cells. Moreover, we evaluated the potential mechanism in vitro to determine the sensitization to oxaliplatin induced by WASF3.ResultsWASF3 silencing by small interfering RNA inhibited the proliferation, migration and invasiveness of gastric cancer cells. We also observed that WASF3 knockdown promoted cell apoptosis and enhanced oxaliplatin sensitivity. Furthermore, the sensitization to oxaliplatin induced by WASF3 knockdown depended on the inhibition of Atg12-mediated autophagy.ConclusionsOur analysis demonstrates WASF3 targeting is a new potential therapeutic strategy for gastric cancer.