Co-expression of heat shock protein 70 and glucose-regulated protein 94 in human gastric carcinoma cell line BGC-823

AIM:To investigate the co-expression and significance of heat shock protein 70 (HSP70) and glucose-regulated protein 94 (grp94) in human gastric carcinoma cell line BGC-823. METHODS: The expression and localization of HSP70 and grp94 in human gastric carcinoma cell line BGC-823 were determined by immunocytochemistry and indirect immunofluorescence cytochemical staining. Flow cytometry was used to analyze the correlation between expression of HSP70, grp94 and cell cycle in BGC-823 cell line. RESULTS: Gastric cancer cell line BGC-823 expressed high level of HSP70 and grp94. The positive rate of HSP70 and grp94 was 84.9±4.94% and 79.6±5.16%, respectively. Both of them were stained in cell plasma. There was a significant difference compared with control group (1.9±0.94%, P<0.01). During the cell cycle, HSP70 and grp94 were continuously expressed in BGC-823. CONCLUSION: HSP70 and grp94 are highly expressed in human gastric carcinoma BGC-823 cells through the whole cell cycle. There is no relationship between expression of HSP70, grp94 and cell cycle.     

Anticancer effect and apoptosis induction of gambogic acid in human gastric cancer line BGC-823

AIM: To investigate the anticancer effect of a traditional Chinese medicine gambogic acid (GA) in human gastric cancer line BGC-823 and further study the mechanism of apoptosis induction of GA. METHODS: Low differential human gastric cancer line BGC-823 were treated with GA at different doses and different times, the inhibitory rates were detected by MTT assay. Apoptosis induced by GA in BGC-823 cells was observed by Annexin-V/PI doubling staining flow cytometry assay. And T/C (%) was chosen to detect the inhibition of GA on human gastric adenocarcinoma BGC-823 nude mice xenografts. Apoptosis on nude mice xenografts was observed by Annexin-V/PI doubling staining flow cytometry assay and DNA fragmentation assay. To further determine the molecular mechanism of apoptosis induced by GA, the changes on the expression of bcl-2 and bax genes were detected by RT-PCR. RESULTS: After incubation with GA, low differential human gastric cancer line BGC-823 was dramatically inhibited in a dose-dependent manner. After these cells were exposed to GA for 24, 48 and 72 h, the IC50 value was 1.02±0.05, 1.41±0.20 and 1.14±0.19 μmol/L, respectively. Apoptosis in BGC-823 cells induced by GA was observed by Annexin V/PI doubling staining flow cytometry assay. The apoptotic population of BGC-823 cells was about 12.96% and 24.58%, respectively, when cells were incubated with 1.2 μmol/L GA for 48 and 72 h. T/C (%) of human gastric carcinoma adenocarcinoma BGC-823 nude mice xenografts was 44.3, when the nude mice were treated with GA (8 mg/kg). Meanwhile, apoptosis induced by GA was observed in human gastric carcinoma adenocarcinoma BGC-823 nude mice xenografts. The increase of bax gene and the decrease of bc1-2 gene expressions were found by RT-PCR. CONCLUSION: The inhibition of GA on human gastric cancer line BGC-823 was confirmed. This effect connects with the inducing apoptosis in BGC-823 cells and the molecular mechanism might be related to the reduction of expression of apoptosis-regulated gene bcl-2, and the improvement of the expression of apoptosis-regulated gene bax. The result was also confirmed in vivo.     

ERK on apoptosis of gastric cancer cells induced by microRNA-433

<正>Objective To investigate the role of ERK in the apoptosis of gastric cancer cells induced by miR-433.Methods Lentivirus was used to transfect BGC-823 gastric cancer cell line to over-express miR-433. The blank control group (BGC-823), negative control group(BGC-823+miR-433 negative control) and experimental group (miR-433+miR-433, BGC-823-pMD18-T-     

Gastric cancer cell lines induced by trichostatin A

AIM： To explore the effect of trichostatin A （TSA） on apoptosis and acetylated histone H3 levels in gastric cancer cell lines BGC-823 and SGC-7901. METHODS： The effect of TSA on growth inhibition and apoptosis was examined by MTT, fluorescence microscopy and PI single-labeled flow cytometry. The acetylated histone H3 level was detected by Western blot. RESULTS： TSA induced apoptosis in gastric cancer cell lines BGC-823 and SGC-7901 was in a dose and time-dependent manner. Apoptotic cells varied significantly between TSA treated groups （37.5 ng/mL 72 h for BGC-823 cell line and 75 ng/mL 72 h for SGC-7901 cell line） and control group （0.85 ± 0.14 vs 1.14 ± 0.07, P = 0.02; 0.94 ± 0.07 vs 1.15 ± 0.06, P = 0.02）. Morphologic changes of apoptosis, including nuclear chromatin condensation and fluorescence strength, were observed under fluorescence microscopy. TSA treatment in BGC-823 and SGC-7901 cell lines obviously induced cell apoptosis, which was demonstrated by the increased percentage of sub-G1 phase cells, the reduction of Gl-phase cells and the increase of apoptosis rates in flow cytometric analysis. The result of Western blot showed that the expression of acetylated histone H3 increased in BGC-823 and SGC-7901 TSA treatment groups as compared with the control group.CONCLUSION： TSA can induce cell apoptosis in BGC-823 and SGC-7901 cell lines. The expression of acetylated histone H3 might be correlated with apoptosis.     

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.     

Effects of human microRNA-181a-5p on proliferation and migration of gastric cancer cells

<正>Objective To preliminarily explore the effects of human microRNA-181a on migration of gastric cancer cells and its mechanism.Methods The expression of miRNA-181a-5p in gastric cancer cell line GC9811 and peritoneal high metastasis gastric cancer cell line GC9811-P were tested by quantitative real-time polymerase chain reaction(qRT-PCR).GC9811 cell line was transfected     

Paeonol inhibits tumor growth in gastric cancer in vitro and in vivo

AIM:To investigate the anti-tumor effects of paeonol in gastric cancer cell proliferation and apoptosis in vitro and in vivo.METHODS:Murine gastric cancer cell line mouse forestomach carcinoma(MFC) or human gastric cancer cell line SGC-7901 was cultured in the presence or absence of paeonol.Cell proliferation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay,and cell cycle and apoptosis by flow cytometry and TUNEL staining.Tumor growth after subcutaneous implantation of MF...     

Baicalin induces apoptosis of gastric cancer MGC-803 and BGC-823 cells through death receptor pathway

<正>Objective To investigate the effects of baicalin on the proliferation and apoptosis of human gastric cancer BGC-823 and MGC-803 cells and to explore the possible molecular mechanism.Methods The proliferation of MGC-803 and BGC-823 cells after treatment with 10,20,40,80,160 and 320μmol/L baicalin for 24,48,72 and96 h,respectively was detected by MTT assay.After     

In vitro effects of recombinant human growth hormone on growth of human gastric cancer cell line BGC823 cells

AIM:To study the effects of recombinant human growthhormone (rhGH) on growth of human gastric cancer cellline in vitro.METHODS:Experiment was divided into control group,rhGH group,oxaliplatin (L-OHP) group and rhGH L-OHPgroup.Cell inhibitory rate,cell cycle,cell proliferation index(PI) and DNA inhibitory rate of human gastric cancer lineBGC823,at different concentrations of rhGH treatment werestudied by cell culture,MTT assay and flow cytometry.RESULTS:The distinctly accelerated effects of rhGH onmultiplication of BGC823 cell line were not found in vitro.There was no statistical significance between rhGH groupand control group,or between rhGH L-OHP group and L-OHP group (P>0.05).The cell growth curve did not rise.Cell inhibitory rate and cells arrested in G_0-G_1 phase wereobviously increased.Meanwhile,cells in S phase and PIwere distinctly decreased and DNA inhibitory rate wasobviously increased in rhGH L-OHP group in comparisonwith control group and rhGH group,respectively (P<0.01).Cell inhibitory rate showed an increasing trend and PIshowed a decreasing trend in rhGH L-OHP group comparedwith L-OHP group.CONCLUSION:In vitro rhGH does not accelerate themultiplication of human gastric cancer cells.It may increasethe therapeutic efficacy when it is used in combination withanticancer drugs.     

Moleucle action mechunisms of NM-3 on human gastric cancer SGC-7901 Cells in vivo or in vitro

AIM: To study the moleucle action mechunisms of NM-3 on the growth of human gastric cancer SGC-7901 cells in vivo or in vitro.METHODS: 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 deoxyuridine triphosphate-fluorescene nick end labeling (TUNEL)method and flow cytometry analysis.RESULTS: 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-3treatment 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 % VS11.86±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-L. 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.CONCLUSION: 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.     

β-elemene enhances the radiosensitivity of gastric cancer cells by inhibiting Pak1 activation

AIM:To explore the potential of β-elemene as a radiosensitizer for gastric cancer cells and the underlying mechanisms.METHODS:SGC7901,MKN45,MKN28,N87,and AGS human gastric cancer cell lines were used to screen for radioresistant gastric cancer cell lines. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium(MTT) assay was used to determine the effects of β-elemene and IPA-3 on cell viability in MKN45 and SGC7901 gastric cancer cell lines. A clonogenic survival assay and annexin V-FITC/PI apoptosis detection assay were used to evaluate cellular radiosensitivity and radiation-induced cell death,respectively. A proteomic method,isobaric tags for relative and absolute quantitation(i TRAQ),was employed to screen the proteins regulated by β-elemene pretreatment prior to ionizing radiation(IR) in SGC7901 gastric cancer cell line. IPA-3 was used as a specific small molecule inhibitor of p21-activated protein kinase 1(Pak1) to target Pak1 signaling. Protein levels of PAK1IP1(p21-activated protein kinase-interacting protein 1),total Pak1(t-Pak1),phospho-Pak1(T423),phospho-ERK1/2( Thr202/Tyr204),and cleaved caspase-3(17 k Da) were assessed by western blotting.RESULTS:MKN45 and SGC7901 gastric cancer cell lines were relatively more resistant to IR. β-elemene pretreatment decreased clonogenic survival following IR in MKN45 and SGC7901 gastric cancer cell lines. Additionally,β-elemene pretreatment prior to IR increased radiation-induced cell death compared with IR alone in MKN45(10.4% ± 0.9% vs 34.8% ± 2.8%,P 0.05) and SGC7901(11.6% ± 0.9% vs 46.7% ± 5.2%,P 0.05) human gastric cancer cell lines,respectively,consistent with the level of cleaved caspase-3(17 k Da). Through i TRAQ analysis and western blot validation,we found that β-elemene upregulated PAK1IP1 and downregulated phospho-Pak1(T423) and phosphoERK1/2 in SGC7901 gastric cancer cells. IR increased the level of phospho-Pak1(T423). Pretreatment with β-elemene decreased radiation-induced Pak1 and ERK1/2 phosphorylation. Inhibition of Pak1 using IPA-3 decreased clonogenic survival following IR. In addition,IPA-3 increased radiation-induced cell death in MKN45(13.4% ± 0.3% vs 26.6% ± 1.0%,P 0.05) and SGC7901(16.0% ± 0.6% vs 37.3% ± 1.7%,P 0.05) gastric cancer cell lines,respectively,consistent with the level of cleaved caspase-3(17 k Da). Western blotting showed that IPA-3 decreased radiation-induced Pak1 and ERK1/2 phosphorylation.CONCLUSION:This is the first demonstration that β-elemene enhances radiosensitivity of gastric cancer cells,and that the mechanism involves inhibition of Pak1 signaling.     

Hypermethylation and aberrant expression of Wnt antagonist secreted frizzled-related protein 1 in gastric cancer

AIM： To identify the methylation of secreted frizzled-related protein 1 （SFRP1） in gastric cancer and to investigate the aberrant expression of SFRP1 and its correlation with the clinical pathological features of patients.
METHODS： We determined SFRP1 methylation and SFRP1 mRNA expression in 3 gastric cancer cell lines SGC-7901, BGC-823, HGC-27, from 52 primary gastric cancer specimens and matched tumor adjacent tissue specimens by methylation-specific （MSP） PCR and RT-PCR respectively. Fisher＇s exact test was used to analyze the statistical association between clinical pathological data and aberrant expression of SFRP1.
RESULTS： In 3 cancer cell lines, BGC-823 and HGC-27 had methylated SFRP1 and lost SFRP1 mRNA expression. After treatment of BGC-823 and HGC-27 with the demethylating agent, 5-aza-2′-deoxycytidine, SFRP1 was re-expressed. In 52 primary gastric cancer specimens and matched tumor adjacent tissue specimens, hypermethylation of SFRP1 was detected in 23 （44%） and 8 （15%） specimens respectively （x^2= 10.34, P 〈 0.01）. Loss of SFRP1 expression was detected in 17（33%） and 6 （12%） specimens respectively （x^2= 6.75, P 〈 0.01）. There was a significant correlation between SFRP1 hypermethylation and SFRP1 expression loss. SFRP1 expression was also correlated significantly with tumor stage and lymph node status, but not with patient sex, age and histological type.
CONCLUSION： SFRP1 inactivation is a common and early event caused mainly by hypermethylation in gastric cancer. SFRP1 expression loss may be correlated with tumor metastasis in primary gastric cancer.