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Aim To investigate whether diallyl disul-fide (DADS) augments the sensitivity of DJ-1 (protein/ nucleic acid deglycase) overexpressed human gastric SGC7901 cells to 5-FU (5-fluorouracil). Methods The experimental groups include control group, DADS group, VCR (vincristine) group, VCR + DADS group, DJ-1 group, DJ-1 + DADS group. MTT was used to analyze the effect of DADS on 5 -FU (5 -fluorou- racil) induced proliferation inhibition. Flow cytometry was performed to examine the effect of DADS on cell apoptosis. RT-PCR, Western blot, and immunofluo-rescence were used for determine the effect of DADS on the drug resistance associated gene expression. Results DADS enhanced the proliferation inhibitory effect of 5-FU on DJ-1 overexpressed cells and VCR resistant cells. DADS could induce apoptosis in VCR-resistant cells. DADS downregulated the expression of DJ-1 while inducing apoptosis in DJ-1 overexpressed cells. DJ-1 overexpression upregulated the expression of P-gp (P-glycoprotein), Bcl-2, and XIAP (X-linked inhibitor of apoptosis protein), downregulated the expression of caspase-3. DADS decreased the expression of P-gp, Bcl-2, and XIAP, while increased the expression of caspase-3 in DJ-1 overexpressed cells and VCR-resistant cells. Conclusions DADS can augment the sensitivity of DJ-1 overexpressed cells to 5-FU, which is related to its antagonism against DJ-1 mediated upregula- tion of P-gp, Bcl-2, XIAP, and downregulation of caspase-3.
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ObjectiveTo explore the inhibitory effect of different concentration of baicalin （0， 100， 200， 400 μmol·L-1） on the proliferation of human gastric cancer SGC-7901 cells and the underlying mechanism. MethodSGC-7901 cells were treated with baicalin. Then methyl thiazolyl tetrazolium （MTT） assay was employed to examine the inhibitory effect of baicalin on the cells. At the same time， ferrostatin-1 （Fer-1） was added to observe the viability of cells after baicalin treatment. The expression of ferroptosis-related genes was detected by Real-time polymerase chain reaction （Real-time PCR） and Western blot. The content of malondialdehyde （MDA） and the level of glutathione （GSH） were detected respectively by MTT assay and enzyme-linked immunosorbent assay. The role of tumor protein 53 （p53）/solute carrier family 7 member 11 （SLC7A11） pathway in the regulation of ferroptosis was investigated respectively via overexpression and small interfering RNA （siRNA） methods. ResultCompared with the blank group， baicalin decreased the viability of SGC-7901 （P<0.05， P<0.01） in a dose- and time-dependent manner. The intervention of Fer-1 significantly alleviated the decrease of SGC-7901 cell viability caused by baicalin （P<0.01）. In addition， compared with the baicalin group， Fer-1+baicalin group showed decrease in MDA content and the mRNA and protein levels of prostaglandin-endoperoxide synthase 2 （PTGS2） in the cells （P<0.01）， and increase in GSH activity and mRNA and protein levels of glutathione peroxidase 4 （GPX4） （P<0.01）. The protein level of SLC7A11 in the baicalin group was decreased compared with that in the blank group （P<0.05， P<0.01） in a dose-dependent manner. Compared with the baicalin group， the reactive oxygen species （ROS） level and MDA content in SLC7A11-overexpressing cells were significantly decreased after baicalin treatment （P<0.01）， and the GSH activity was significantly increased （P<0.01）. The fluorescence intensity of p53 in the cells of the baicalin group was increased compared with that of the blank group （P<0.01）. Compared with the baicalin group， the expression level of p53 protein in the cells transfected with p53 siRNA was significantly decreased after baicalin treatment （P<0.01）， and the expression level of SLC7A11 was significantly increased （P<0.01）. ConclusionBaicalin can effectively inhibit the proliferation of SGC-7901 cells by regulating p53/SLC7A11-mediated ferroptosis.
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ObjectiveTo investigate the effect of Draconis Sanguis petroleum ether fraction （DSPEF） on the proliferation， apoptosis， migration， and autophagy of human gastric cancer HGC-27 and MGC-803 cells， and preliminarily elucidate its molecular mechanism. MethodCell counting kit-8 （CCK-8） assay was used to detect the effect of DSPEF at different concentrations （0， 20， 40， 60， 80 mg·L-1） on the proliferation of HGC-27 and MGC-803 cells after 24， 48， 72 h. Hoechst staining and flow cytometry were used to explore the effects of DSPEF at different concentrations on the apoptosis and apoptosis rate of HGC-27 and MGC-803 cells after 48 h treatment， respectively. The wound healing assay and acridine orange staining were used to investigate the effects of DSPEF on the migration and autophagy of HGC-27 and MGC-803 cells， respectively. Western blot was used to detect the expression levels of signaling pathway-related proteins in HGC-27 and MGC-803 cells treated with DSPEF for 48 h. ResultCompared with the control group， DSPEF（30 mg·L-1） inhibited the proliferation and migration of HGC-27 and MGC-803 cells in a concentration- and time-dependent manner （P<0.05）， and induced the apoptosis （P<0.01） and autophagy of HGC-27 and MGC-803 cells. DSPEF （60 mg·L-1） down-regulated the protein levels of phosphorylated mammalian target of rapamycin （p-mTOR） （P<0.05， P<0.01） and down-regulated phospho-signal transducer and activator of transcription 3 （p-STAT3） in HGC-27 and MGC-803 cells （P<0.01）， suggesting that DSPEF presumedly inhibited the proliferation and migration of human gastric cancer HGC-27 and MGC-803 cells and induced their apoptosis and autophagy by inhibiting the mTOR/STAT3 signaling pathway. ConclusionThe down-regulation of the mTOR/STAT3 signaling pathway may be involved in the anti-gastric cancer effect of DSPEF. This study is expected to provide a reference for the investigation of the anti-tumor effect of Draconis Sanguis.
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OBJECTIVE@#To determine the effect of Zanthoxylum piperitum extracet (ZPE) on apoptosis and analyze anticancer substances in ZPE, changes in proteins related to apoptosis, and pathological changes in tumors in mouse.@*METHODS@#Fifteen 4-week-old female BALB/c nu/nu mice were divided into 3 groups depending on ZPE dose, with 5 in each group. AGS gastric carcinoma cells (1 × 10@*RESULTS@#High performance liquid chromatography (HPLC) analysis showed that ZPE contained organic sulfur compounds such as alliin and S-allylcysteine. MTT assay results revealed that ZPE (10-85 µ g/mL) could effectively inhibit the growth of AGS gastric cancer cells at higher concentrations (P<0.05, P<0.01). The annexin V & dead cell staining assay and cell cycle arrest assay confirmed a dose-dependent increase in the apoptosis rate and G@*CONCLUSION@#ZPE decreases AGS cell proliferation and induces apoptosis by inhibiting Akt and MDM2 expression.
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Animals , Female , Mice , Apoptosis , Cell Line, Tumor , Cell Proliferation , Mice, Inbred BALB C , Plant Extracts/therapeutic use , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction , Stomach Neoplasms/drug therapy , Tumor Suppressor Protein p53/metabolism , Zanthoxylum/metabolismABSTRACT
Objective: To investigate the inhibitory effect of usnicoyinamide on the proliferation of gastric cancer cell line SGC-7901 and its mechanism. Methods: SGC-7901 cells were cultured in vitro and divided into two groups: control group and experimental group with different concentrations of usnicoyinamide. The morphology of each group of cells was observed by a microscope; Proliferation of SGC-7901 cells was measured by MTT assay; The mechanism of apoptosis was studied by AnnexinV/PI double staining and DAPI fluorescence staining; Flow cytometry was used to detect the effect of usnicoyinamide on the cell cycle; Effect of usnicoyinamide on invasion and migration of SGC-7901 cells was detected by cell scratch test. Results: After SGC-7901 cells were treated with usnicoyinamide, the cells were wrinkled, deformed and adherent cells fell off; The results of MTT showed that the inhibition of the proliferation of SGC-7901 cells was a significant dose-effect relationship and time-dependent; The results of AnnexinV/PI double staining showed that nicotine increased the late apoptosis rate of SGC-7901 cells, and DAPI staining showed obvious nuclear concentration and nuclear fragmentation of apoptosis. The results of flow cytometry showed that the cell cycle of SGC-7901 cells stagnated in S phase; Scratch test showed that the mobility of SGC-7901 cells was decreased more obviously with the prolongation of time and the increase of concentration. Conclusion: Usnicoyinamide can inhibit the proliferation of gastric cancer cell line SGC-7901, and its mechanism may be achieved by inducing late apoptosis, inducing S phase cell arrest and inhibiting the invasion and migration of SGC-7901 cells.
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Objective The active protein of traditional Chinese medicine has anti-tumor effect, and salvia miltiorrhiza is an important anti-tumor traditional Chinese medicine. Here, the effect of Salvia miltiorrhiza lectin protein (SMLP) on the apoptosis of gastric cancer cells was studied. Methods SMLP expressed and purified from prokaryotic cells was used to treat the gastric cancer cells SGC-7901. The experiment was divided into the control group (untreated) and the SMLP treatment group (final concentration of 10 μmol / L of SMLP was treated for 24 h). Real-time RT-PCR and Western blot were used to detect the changes of apoptosis gene expression. Flow cytometry and Hoechst staining were applied to detect the apoptotic status. Caspase-3 and Caspase-9 activity assay kits were used to detect the apoptotic level. Results The result of RT-PCR showed that the mRNA level of Bax in the SMLP treatment group was significantly higher than in the control group (1.00±0.12 vs 0.67±0.10）(P<0.05). After treatment with SMLP to gastric cancer cells, the activity and expression level of cleaved Caspase-3 and Caspase-9 were increased significantly compared with the control group (P<0.05). The cell nucleus in the control group was bigger and rounder, with smooth surface and uniform staining, whilst in the SMLP-treated group, the cell nucleus became deeper with pyknosis, representing typical morphological characteristics of apoptosis. The early apoptosis level in the control group was 6.55%, and the SMLP treatment group reached 10.18%, showing an increase in the level of apoptosis. Conclusion SMLP expressed and purified in vitro can promote the apoptosis of gastric cancer cells, which is of great significance for further revealing the function of plant lectin and investigating the anti-tumor effect on the protein of traditional Chinese medicine.
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Aim: To investigate the expression and i-dentification of differential miRNAs in human gastric cancer MGC803 cells induced by diallyl disulfide (DADS). Methods: Differential miRNAs expression in human gastric cancer MGC803 cells induced by DADS was detected and identified by miRNA chip and qPCR. Results: MiRNAs chip detection showed upregulation of miR-200b, miR-22, miR-7, miR-143, miR-138, miR-34a and miR-150, and down-regulation of miR-222, miR-21, miR-15b, miR-182 and miR-18a in differential miRNAs of MGC803 cells treated with 3 0 mg · IT-1 DADS at 24 h(P<0.05). And qPCR demonstrated that the expressions of miR-200b, miR-22, miR-7, miR-143, miR-138, miR-34a and miR-150 was up-regulated in MGC803 cells treated with 30 mg · L-1 DADS(P <0. 05). Moreover, qPCR showed that the expressions of miR-200b and miR-22 in various human gastric cancer cells including MGC803, BGC823, MKN28, SGC7901 and HGC27 cells were lower than normal human gastric cancer GES-1 cells (P <0. 05). The expression of miR-200b and miR-22 in gastric cancer tissues was significantly lower than that in normal gastric tissues (P < 0. 05). Conclusions: The expression of down-regulation of 7 miRNA and up-regulation of 5 miRNA in differential miRNAs in MGC803 cells induced by DADS. The expression of down-regulation of miR-200b and miR-22 in gastric cancer tissues and cells. DADS could up-regulate the expression of miR-200b and miR-22 in gastric cancer cells.
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Objective: To explore the effect of Helicobacter pylori virulence factor cytotoxin-associated gene A protein (CagA) on the extracellular regulated protein kinase (ERK) signaling pathway, and to elucidate the carcinogenesis mechanism of CagA. Methods: The pcDNA3. 1/CagA eukaryotic expression vector was constructed, and the gastric cancer AGS cells were divided into blank control group (blank vector transfection), CagA transfection group (GZ7/CagA transfection), and CagA + ERKi group (ERK1/2 inhibitor pretreatment + GZ7/CagA transfection). The expression levels of CagA, phosphorylated ERK (p-ERK), total ERK (T-ERK), B-lymphocytoma-2 (Bcl-2), Bcl-2-related X protein (Bax) and cleaved caspase-3 proteins in the cells in various groups were determined by Western blotting method. The activities of AGS cells in various groups were determined by CCK-8 method, and the apoptotic rates of AGS cells were determined by flow cytometry. Results: Compared with blank control group, the expression levels of CagA, p-ERK, and Bel-2 proteins in CagA transfection group were significantly increased (P<0. 01), and the expression levels of Bax and cleaved caspase-3 proteins were significantly decreased (P<0. 01). Compared with CagA transfection group, the expression levels of p-ERK and Bel-2 proteins in CagA+ERKi group were significantly decreased (P<0. 01), and the expression levels of Bax and cleaved caspase-3 proteins were significantly increased (P<0. 01). Compared with CagA transfection group, the activities of gastric cancer cells in CagA + ERKi group at different time points were significantly decreased (P< 0. 01). Compared with CagA transfection group, the apoptotic rate of gastric cancer cells in CagA + ERKi group was significantly increased (P<0. 05). Conclusion: Helicobacter pylori virulence factor CagA can inhibit the proliferation of gastric cancer cells and promote the apoptosis of gastric cancer cells, and its mechanism may be related to the activation of ERK signaling pathway by CagA.
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Objective To investigate the effect of microRNA-1183 on proliferation and metastasis on gastric cancer cells and to explore the role of microRNA-1183 and CBL-B signaling pathways in this process. Methods MGC803 cells were transfected with a microRNA-1183 mimic. Real-time PCR detected the expression of microRNA-1183 in gastric cancer cell line MGC803. MTT detected the proliferative effect of microRNA-1183 on MGC803 gastric cancer cells. A Transwell assay detected the effect of microRNA-1183 on the metastasis of MGC803 gastric cancer cells. A dual luciferase reporter assay detected the binding ability between microRNA-1183 and CBL-B. The expression of the protein was tested by Western blotting. Results MTT assay results showed that microRNA-1183 promoted the proliferation of MGC803 cells. Transwell assay results revealed that microRNA-1183 promoted the metastasis of MGC803 cells. The results of BLAST contrast analysis show that CBL-B is one of the target genes of microRNA-1183. Western blotting analysis showed that the mimic microRNA-1183 inhibited the expression of CBL-B. A dual luciferase reporter assay showed that CBL-B was the target gene of microRNA-1183. A CBL-B knockdown promoted the proliferation and metastasis of MGC803 cells. microRNA-1183 promoted the proliferation and metastasis of MGC803 cells by inhibiting the expression of CBL-B. Conclusion microRNA-1183 can inhibit the proliferation and metastasis of gastric cancer cell lines by inhibiting the expression of CBL-B.
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Objective To study the effect of annonaceous acetogenins (ACGs) on human gastric cancer cells in vitro. Methods After ACGs were administered to gastric cancer cells in vitro, the cell viability, cell adhesion ability and cell migration ability were assessed by MTT assay, adhesion assay and wound-healing assay, respectively. Results ACGs inhibited the cell viability, adhesion ability and migration ability in a dose-dependent manner in gastric cancer cells. Conclusion ACGs could inhibit cell activities of human gastric cancer cells in viro, and will be developed as a promising anticancer candidate and used in gastric cancer.
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AIM:To explore the effect of poncirin on the growth of AGS gastric cancer cells and the underlying mechanism.METHODS:The effect of poncirin on AGS cell viability was measure by MTT assay.The cell cycle distribution and cell apoptosis were analyzed by flow cytometry.Nuclear staining with DAPI was used to reflect the morphological change of the AGS cells treated with poncirin.The protein levels of extrinsic apoptosis pathway-related proteins such as FasL,caspase-8,caspase-3 and PARP,and mitochondria-mediated intrinsic apoptosis pathway-associated proteins such as Bak,Bcl-xL,Bax and caspase-9 were determined by Western blot.RESULTS:Poncirin inhibited the viability of AGS gastric cancer cells in a time-and concentration-dependent manner (P ＜ 0.05).Poncirin induced accumulation of G1 DNA content and significantly increased total apoptosis in the AGS cells.Nuclear staining showed a dose-dependent increase in the number of apoptotic cells after treated with poncirin.The protein level of FasL was upregulated in a dose-dependent manner by treatment with poncirin.Poncirin significantly activated caspase-8 and caspase-3.Moreover,poncirin significantly induced the cleavage of PARP in a dose-dependent manner (P ＜ 0.05).In addition,the protein levels of Bcl-xL,Bax and Bak were unchanged after treated with different doses of poncirin.Furthermore,caspase-9 was not activated by poncirin treatment in the AGS cells.CONCLUSION:Poncirin has the anti-cancer effect via extrinsic apoptosis pathway to inhibit the growth of AGS gastric cancer cells,possibly making it a therapeutic agent for human gastric cancer treatment.
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AIM:To explore the effect of poncirin on the growth of AGS gastric cancer cells and the underlying mechanism.METHODS:The effect of poncirin on AGS cell viability was measure by MTT assay.The cell cycle distribution and cell apoptosis were analyzed by flow cytometry.Nuclear staining with DAPI was used to reflect the morphological change of the AGS cells treated with poncirin.The protein levels of extrinsic apoptosis pathway-related proteins such as FasL,caspase-8,caspase-3 and PARP,and mitochondria-mediated intrinsic apoptosis pathway-associated proteins such as Bak,Bcl-xL,Bax and caspase-9 were determined by Western blot.RESULTS:Poncirin inhibited the viability of AGS gastric cancer cells in a time-and concentration-dependent manner (P ＜ 0.05).Poncirin induced accumulation of G1 DNA content and significantly increased total apoptosis in the AGS cells.Nuclear staining showed a dose-dependent increase in the number of apoptotic cells after treated with poncirin.The protein level of FasL was upregulated in a dose-dependent manner by treatment with poncirin.Poncirin significantly activated caspase-8 and caspase-3.Moreover,poncirin significantly induced the cleavage of PARP in a dose-dependent manner (P ＜ 0.05).In addition,the protein levels of Bcl-xL,Bax and Bak were unchanged after treated with different doses of poncirin.Furthermore,caspase-9 was not activated by poncirin treatment in the AGS cells.CONCLUSION:Poncirin has the anti-cancer effect via extrinsic apoptosis pathway to inhibit the growth of AGS gastric cancer cells,possibly making it a therapeutic agent for human gastric cancer treatment.
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Aim To investigate the up-regulation of miR-22 through Wnt pathway inhibits the proliferation,migration and invasion in human gastric MGC803 cells induced by diallyl disulfide(DADS).Methods The effects of proliferation,migration,and invasion of gastric cancer cells were evaluated by MTT,wound-healing and invasion assays.Online prediction software was applied to search the target gene of miR-22.Luciferase report gene assay was used to assess the target genes Wnt-1 of miR-22.The expressions of Wnt-1,β-catenin and TCF-4 were tested by qRT-PCR and Western blot,respectively.Results MTT showed that DADS and miR-22 notably decreased the proliferation compared with control group(P<0.05).Wound-healing assay showed that DADS and miR-22 could significantly inhibit the migration of MGC803 cells compared with the control group, especially in miR-22+DADS(P<0.05). Invasion assay showed that DADS and miR-22 could markedly inhibit the invasion of MGC803 cells compared with the control group, especially in miR-22+DADS(P<0.05). Online prediction software to search the target gene exhibited that Wnt-1 may be a target gene of miR-22. Luciferase report gene assay disclosed that Wnt-1 was identified as a direct target of miR-22. Qrt-PCR showed that the expression of Wnt-1 Mrna was respectively down-regulated by DADS and miR-22 compared withcontrol group, especially in miR-22+DADS(P<0.05). Western blot exhibited that DADS and miR-22 obviously suppressed the expressions of Wnt-1, β-catenin and TCF-4 proteins, especially in miR-22+DADS(P<0.05).Conclusion Up-regulation of miR-22 through Wnt pathway can remarkably suppress the proliferation, migration and invasion in MGC803 cells by DADS.
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BACKGROUND: Extensive evidence has accumulated regarding the role of mesenchymal stromal cells (MSCs) in tumor progression, but the exact effects and mechanisms underlying this role remain unclear. We investigated the effects of MSC-associated tumor progression in MSC-sarcoma models and a gastric cancer metastatic model. METHODS: We conducted an in vitro growth kinetics assay and an in vivo tumor progression assay for sarcoma cells and gastric cancer cells in the presence or absence of MSCs. RESULTS: MSC-cocultured human fibrosarcoma cells (HT1080) showed accelerated growth compared with HT1080 alone (79- vs 37-fold change, p<.050). For HT1080, human MSC-coinjected tumors showed significantly greater and highly infiltrative growth compared to those of HT1080 alone (p=.035). For mouse fibrosarcoma cells (WEHI164), mouse MSC-coinjected tumors had greater volume than those of WEHI164 alone (p=.141). For rat sarcoma cells (RR1022), rat MSC-coinjected tumors exhibited greater volume and infiltrative growth than those of RR1022 alone (p=.050). For human gastric cancer cells (5FU), tumors of 5FU alone were compact, nodular in shape, and expansile with good demarcation and no definite lung metastatic nodules, whereas tumors grown in the presence of human MSCs showed highly desmoplastic and infiltrative growth and multiple lung metastasis. CONCLUSIONS: We observed morphological evidence for MSC-associated tumor progression of fibrosarcomas and gastric cancer cells.
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Animals , Humans , Mice , Rats , Fibrosarcoma , Fluorouracil , Kinetics , Lung , Mesenchymal Stem Cells , Neoplasm Metastasis , Sarcoma , Stomach NeoplasmsABSTRACT
10.3969/j.issn.1007-3969.2013.04.003
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Objective: Cell cycle has recently become more appealing as a new target of anti-carcinogen-ic agent. Diallyl disulfide (DADS) inhibits growth and induces call cycle G_2/M arrest in human gastric cancer BGC823 cells. Cell division cycle protein 25C (Cdc25C) and CyclinB1 expression are involved in G_2/M arrest.However, mechanisms of G_2/M arrest are not yet fully understood. The aim of this study was to elucidate the mechanism of cell cycle G_2/M arrest in human gastric cancer BGC823 cells induced by DADS. Methods: The expression of chk1 and Chk2 mRNA associated with cell cycle arrest of BGC823 cells after the induction with DADS for 1 or 2 days was detected by RT-PCR. The protein expression of cycle-related proteins ATM-RAD3-related gene (ATR), checkpoint kinase1 (Chk1), checkpoint kinase 2 (Chk2), P-ATR, P-Chk1 and P-Chk2 was measured by Western blot. Interaction between Chk1/2 and Cdc25C was analyzed by immuno-precipitation. Results: After the cells were treated with 15 mg/L DADS for 1 or 2 days, the expression of Chk1 and Chk2 mRNA was not significantly different from that in untreated cells (P>0.05). Western blot analysis showed that the expression of total Chk1 and Chk2 treated with 15 mg/L DADS was not significantly different from that in untreated cells. But phospho-chk1 showed a significant increase after stimulation with 15 mg/L DADS for 2h to 12h and continued to increase gradually as time went on (P<0.05). Phospho-Chk2 showed a eak expression and a weaker expression after stimulation with DADS, but the changes were not statistically significant (P>0.05). Addition of 15 mg/L DADS to BGC823 cells for 15 rain to 120 min resulted in an increase in phospho-ATR expression, whereas no changes were found in ATR expression (P<0.05). The Chk1 Ab in-creasingly precipitated Cdc25C in BGC823 cells treated with DADS (P<0.05). In contrast, Chk2 Ab failed to change precipitation with Cdc25C by DADS (P>0.05). Conclusion: Activation of chk1 was involved in cell cy-cle G_2/M arrest in BGC823 cells treated with DADS. Cell cycle G_2/M arrest by DADS is associated with phos-phorylation of several cell cycle regulatory proteins including ATR and Chk1 which regulate expression of Cdc25C.
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Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)induces apoptosis in some cancer cells such as breast,prostate,lung,and colon cancer cells,but not normal cells.However,because the effects of TRAIL in gastric cancer cells is unclear,we undertook this study to clarify the effects of TRAIL and its mechanism. To assess the cytotoxicity of TRAIL,two human gastric cancer cell lines,SNU-484 and SNU601,were treated with TRAIL (0-200 ng/mL)in the presence or absence of cycloheximide (1 microgram/mL)for 24 h.Both SNU-484 and SNU-601 were sensitive to TRAIL-induced cell death in a dose-dependent manner.The combination of TRAIL (100 ng/mL)and cycloheximide (1 microgram/mL)for 24 h enhanced cell death and PARP cleavage by promoting activations of caspase-8, caspase-9,and caspase-3,relative to that of TRAIL alone.We further examined the expressions of death receptor 4 (DR4),death receptor 5 (DR5),and FLICE inhibitory protein (FLIP).Although DR4 and DR5 were expressed in both cell lines,the expression of long form (FLIPL )and short form (FLIPS )of FLIP were detected at the low levels. Overexpression of FLIPL or FLIPS in both cell lines rendered the cells resistant to TRAIL.Taken together,our results suggest that FLIP promotes human gastric cancer cell survival against TRAIL-induced apoptosis and is important modulator for TRAIL-induced cell death in human gastric cancer cells.
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Humans , Apoptosis , CASP8 and FADD-Like Apoptosis Regulating Protein , Caspase 8 , Cell Death , Cell Line , Cell Survival , Colonic Neoplasms , Cycloheximide , Necrosis , Receptors, TNF-Related Apoptosis-Inducing Ligand , Stomach NeoplasmsABSTRACT
Objective To observe the effects of VEGF antisense oligonucleotide on growth of micrangium of xenograft in nude mice.Methods VEGF-ASODN was synthesised.After transfection with VEGF-ASODN,RNA copy was detected by real-time PT-PCR,VEGF protein was examined by ELESA,Survival of cells was tested by MTT.Growth of cells was shown by growth curve.After the model of human gastic cancer xenografts in nude mice was developed,model animals were divided randomly into three groups:antisense group、scrambled group and saline group.ResultsVEGF-ASODN can reduce the VEGF mRNA and VEGF protein in cells and supernate remarkably.Survival and growth of cells were suppressed.It can significantly reduce VEGF protein in serum of nude mice.It also reduced the volum and weight of xenografts.Density of micrangium decreased in xenografts.Conclusion VEGF-ASODN can suppress the growth of micrangium in xenografts.
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PURPOSE: Multidrug resistance (MDR) is a phenomenon whereby tumor cell acquire resistance to a broad range of structurally and functionally diverse chemotherapeutic drugs. The most widely implicated mechanism of MDR is that of altered membrane transporter in tumor cells. P-glycoprotein (Pgp), multidrug resistance protein (MRP), and breast cancer-resistance protein (BCRP) are well known membrane transporters, which pump out antitumor agents via an ATP-dependent process, the so called ATP-binding cassette (ABC) superfamily or transporter. This study was undertaken to test the prevalence of each ABC transporter, and which of then exhibit functional activity in various gastric cancer cells. METHODS: The expressions of Pgp, MRP, and BCRP mRNA were determined by RT-PCR assay on 10 gastric cancer cells. The sensitivity to anticancer agents, substrates for each ABC transporter in the gastric cancer cells was determined using the MTT assay. The intracellular accumulation of fluorescent compounds for the functional detection of each ABC transporter was determined using flow cytometry. RESULTS: The Pgp mRNA was expressed at various levels in 9 out of the 10 gastric cancer cells tested, but significantly low. MRP mRNA was constitutively expressed in all the cells. BCRP mRNA was differentially expressed in 5 of the gastric cancer cells. There was no relation between the expressions of Pgp and MRP and the cytotoxicity to each substrate. It was observed that the accumulations of paclitaxel and VP-16 were significantly increased on the additions of PSC833 and probenecid, respectively, in all tested cells. The reversal effect of drug accumulation by each inhibitor was much higher in the MRP than Pgp. With BCRP, the observed cytotoxic effect and amount of mitoxanthrone accumulation were less than in the cells expressing the highest levels of BCRP compared to those that did not. However the mitoxanthrone accumulation was not increased on the addition of FTC in the either cell type. CONCLUSION: This study suggests that of the ABC transporters, MRP has primarily functional activity, whereas that of Pgp is only slight, in the gastric cancer cells. Other possible MDR mechanisms involved will have to be explored in further studies.
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Antineoplastic Agents , ATP-Binding Cassette Transporters , Breast , Drug Resistance, Multiple , Etoposide , Flow Cytometry , Membrane Transport Proteins , Membranes , ATP Binding Cassette Transporter, Subfamily B, Member 1 , Paclitaxel , Prevalence , Probenecid , RNA, Messenger , Stomach NeoplasmsABSTRACT
OBJECTIVE:To study the effects of arsenic trioxide(As 2 O 3 )on the encoding protein expressions of nm23and P53in gastric cancer cells and to study the anti-canecer mechanism of which in the tumor.METHODS:A control group and a test group were set up.The expressions of gene coding proteinum nm23and P53of the gastric cancer cells cultured in vitro by the action of As 2 O 3 were determined by immunohistochemistry method.RESULTS:The expression levels of nm23and P53in gastric cancer cells have been lowered compared with the control group.CONCLUSION:As 2 O 3 can exert its anti-tumor effect by decreasing the expression of gene coding proteinum of nm23and P53.