Effects of allicin on both telomerase activity and apoptosis in gastric cancer SGC-7901 cells

AIM: To investigate the effects of allicin on both telomeraseactivity and apoptosis in gastric cancer SGC-7901 cells.METHODS: The gastric cancer SGC-7901 adenocarcinomacells were treated with allicin and the cell cycle, inhibitoryrate, apoptosis, telomerase activity and morphologic changeswere studied by MTT assay, flow cytometry (FCM), TRAP-PCR-ELISA assay, light microscope, electron microscoperespectively. Results were compared with that of AZT (3′-Azido-3′-deoxythymidine).RESULTS: SGC-7901 cells were suppressed after exposureto allicin of 0.016 mg/ml, 0.05 mg/ml, and 0.1 mg/mi for48 h. Compared with the control, the difference wassignificant (P＜0.05). Allicin could induce apoptosis of thecells in a dose-dependent and non-linear manner andincrease the proportion of cells in the G2/M phase. Comparedwith the control, the difference was significant in terms ofthe percentage of cells in the G2/M phase (P＜0.05). Allicincould inhibit telomerase activity in a time-dependent anddose-dependent pattern. After exposure to allicin at 0.016mg/ml for 24 hours, SGC-7901 cells showed typicalmorphologic change.CONCLUSION: Allicin can inhibit telomerase activity andinduce apoptosis of gastric cancer SGC-7901 cells. Allicinmay be more effective than AZT.

Inhibitory effects of apigenin on the growth of gastric carcinoma SGC-7901 cells

AIM: To explore the growth inhibition and apoptosisinducing effect of apigenin on human gastric carcinoma SGC-7901 cells.METHODS: The effects of apigenin on the growth, clone formation and proliferation of human gastric carcinoma SGC-7901 cells were observed by MTT, clone-forming assay,and morphological observation. Fluorescent staining and flow cytometry analysis were used to detect apoptosis of cells.RESULTS: Apigenin obviously inhibited the growth, clone formation and proliferation of SGC-7901 cells in a dosedependent manner. Inhibition of growth was observed on d 1 at the concentration of 80 μmol/L, while after 4 d,the inhibition rate (IR) was 90%. The growth IRs at the concentration of 20, 40, and 80 μmol/L were 38%, 71%,and 99% respectively on the 7th d. After the cells were treated with apigenin for 48 h, the number of clone-forming in control,20, 40, and 80 μmol/L groups was 217±16.9, 170±11.1(P＜0.05), 98±11.1 (P＜0.05), and 25±3.5 (P＜0.05)respectively. Typical morphological changes of apoptosis was found by fluorescent staining. The cell nuclei had lost its smooth boundaries, chromatin was condensed, and cell nuclei were broken. Flow cytometry detected typical apoptosis peak. After the cells were treated with apigenin for 48 h, the apoptosis rates were 5.76%, 19.17%, and 29.30% respectively in 20, 40, and 80 μmol/L groups.CONCLUSION: Apigenin shows obvious inhibition on the growth and clone formation of SGC-7901 cells by inducing apoptosis.

Effects of a Shuangling Fuzheng anticancer preparation on the proliferation of SGC-7901 cells and immune function in a cyclophosphamide-treated murine model

AIM: To study the inhibitory effects of a Shuangling Fuzheng anticancer preparation (SFAP) on the human gastric cancer cell line SGC-7901 in vitro as well as its immune-modulated effects in a cyclophosphamide-treated murine model. METHODS: MTT experiments and immunocytochemistry ABC experiments were performed for detecting the proliferation of SGC-7901 cells in vitro and protein expression of c-myc. The staphylococcal protein A (SPA) rosette test was utilized for measuring the ratio of T-lymphocyte subsets from peripheral blood in a cyclophosphamide-treated murine model. Enzyme- linked immunosorbant assay (ELISA) was performed for measuring the levels of serum sIL-2R in treated mice, while immunoturbidimetry was used for measuring the levels of immunoglobulins (Ig). RESULTS: SFAP (40-640 mg/L, 48 h) inhibited the proliferation of SGC-7901 cells, and a positive correlation was noted between inhibitory effects and dosage. At a dosage of 160-320 mg/L in cultured cells, the expression of c-myc was decreased. SFAP (50-200 mg/kg) increased the percentage of CD3+ and CD4+ T-lymphocytes, the ratio of CD4/CD8, and the contents of Ig such as IgM, IgG or IgA, but decreased the levels of serum sIL-2R in peripheral blood from cyclophosphamide-treated mice. CONCLUSION: SFAP can inhibit the proliferation of SGC-7901 cells via the c-myc gene. In addition, SFAP can modulat the cellular and humoral immunity in cyclophosphamide-induced immunosuppressed mice.

The effects of vitamin E succinate on the expression of c-jun gene and protein in human gastric cancer SGC-7901 cells

AIM：Toinvestigate the effects of vitamin E succinate(VES)on the expression of c-jun gene and protein in human gastric cancer SGC-7901 cells.METHODS:After SGC-7901cells were treated with VESat different doses(5,10,20mg·L^-1)at different time,reverse transcription-PCR technique was used to detect the level of c-jun mRNA;Western Blot was applied to measure the expression of c-jun protein.RESULTS:After the cells were theated with VESat 20mg·L^-1for 3h,the expression rapidly reached its maximun that was3.5times of UT control(P<0.01).The level of c-jun mRNA was also increased following treatment of VESfor 6h.However the expression after treatment of VES at 5mg·L^-1for24h was 1.6tmes compared with UTcontrol(P<0.01),Western blot analysis showed that the level of c-jun protein was obviusly elevated in VES-treated SGC-7901cells at 20mg·L^-1for3h,The expression of c-jun protein was gradually increased after treatment of VES at 20mg·L^-1for3,6,12and24h,respectively,with an evident time-effect relationship.CONCONCLUSION:The levels of c-jun mRNA and protein in VES-treated SGC-7901cells were increased in a dose-and time-dependent manner;the expression of c-jun was prolonged by VES,indicating that c-jun is involvedin VES-induced apoptosis in SGC-7901 cells.

Apoptosis of human gastric cancer SGC-7901 cells induced by mitomycin combined with sulindac

AIM: To investigate the effects of mitomycin (MMC)combined with sulindac on cell viability, apoptotic induction and expression of apoptosis-related gene Bcl-2 and cyclooxygenase-2 (COX-2)in gastric cancer SGC-7901cells.METHODS: Human gastric cancer SGC-7901 cells were divided into three treatment groups,namely sulindac treatment group, MMC treatment group and combined sulindac with MMC treatment group. After being treated with drugs, cell viability was examined by MTr assay.Flow cytometry was used to evaluate the cell cycle distribution and apoptotic rates. Morphology of the cells was observed under light microscope and interactive laser microscope. Expression of COX-2 and Bcl-2 was determined by immunocytochemical method.RESULTS: After exposure for 12 h to three kinds of drugs,gastric cancer SGC-7901 cells presented some morphological features of apoptosis, including cell shrinkage, nuclear condensation, DNA fragmentation and formation of apoptotic bodies. Growth inhibition was more obvious in combined sulindac with MMC treatment group and sulindac treatment group than in MMC treatment group. The apoptotic rates in co-treated cells and MMC-treated cells 24 h after treatment were 12.0% and 7.2%, respectively.After exposure for 24 h to MMC, the expression of COX-2and Bcl-2 protein was up-regulated, COX-2 levels were down-regulated but Bcl-2 gene expression was not changed significantly in combined treatment group.CONCLUSION: MMC-induced apoptosis is reduced by up-regulating the expression of COX-2 and Bcl-2 genes.MMC combined with sulindac can suppress the growth of gastric cancer cells through induction of apoptosis mediated by down-regulation of apoptosis-related Bcl-2and COX-2 gene.

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.

Effects of Leaf Extract of Phyllanthus reticulatus from Guangxi on Human Gastric Cancer SGC-7901 Cells in vitro

[Objectives]To observe the effect of drug-containing serum from different extracts of Phyllanthus reticulatus leaf on the proliferation of human gastric cancer SGC-7901 cells and the effect of in vivo on the life extension rate of mice with H22 ascites tumor,and to investigate the effects of chemical components such as Corilagin,ethyl gallate,ethyl brevifolincarboxylate,and gallic acid on the proliferation of human gastric cancer SGC-7901 cells.[Methods]MTT method was used to observe the inhibitory effect of drug-containing serum of different extracts of P.reticulatus leaf on human gastric cancer SGC-7901 cells in vitro to determine its active site.The active site was used as the research object to establish a Kunming mouse ascites tumor model,to investigate the effect on the life extension rate of mice with H22 ascites tumor,to further separate the monomer components from the effective fraction and investigate its effect on human gastric cancer SGC-7901 cells.[Results]Compared with the 10%blank serum control group,10%drug-containing serum of ethyl acetate and n-butanol in P.reticulatus leaf had significant inhibitory effect on the proliferation of human gastric cancer SGC-7901 cells,and the inhibition rate was 34.99%and 28.68%,respectively(P<0.05).Compared with the blank group,the survival time of the high dose group of ethyl acetate in P.reticulatus leaf was significant(P<0.05).Gallic acid,Corilagin,and Brevifolincarboxylic acid ethyl ester had a significant inhibitory effect on the proliferation of human gastric cancer SGC-7901 cells,with IC 50 of 26.52,70.45,and 158.86μg/mL,respectively.Ethyl gallate had no inhibitory effect on the proliferation of human gastric cancer SGC-7901 cells,and its IC 50 was 251.96μg/mL.[Conclusions]The drug-containing serum of ethyl acetate and n-butanol extract of P.reticulatus can inhibit the proliferation of human gastric cancer SGC-7901 cells.Ethyl acetate of P.reticulatus leaves can increase the life extension rate of mice with H22 ascites tumor.Gallic acid,Corilagin,and Brevifolincarboxylic acid ethyl ester isolated from its active site are the material basis for inhibiting the proliferation of human gastric cancer SGC-7901 cells.

Crebanine N-oxide, a natural aporphine alkaloid isolated from Stephania hainanensis, induces apoptosis and autophagy in human gastric cancer SGC-7901 cells

Objective: To investigate the cytotoxic effects and the potential mechanisms of crebanine N-oxide in SGC-7901 gastric adenocarcinoma cells. Methods: The cytotoxicity of crebanine N-oxide was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay and cellular morphology was observed under a microscope. Cell apoptosis was determined by flow cytometry using propidium iodide staining. The expression levels of apoptotic-related proteins, cleaved caspase-3, cytochrome C, p53 and Bax, and autophagyrelated proteins p62, beclin1 and LC3 were detected by Western blotting assays. Results: Crebanine N-oxide treatment significantly inhibited the proliferation of SGC-7901 cells in a dose-dependent and timedependent manner via induction of G2-phase cell cycle arrest, apoptosis, and autophagy in SGC-7901 cells.Conclusions: Crebanine N-oxide could inhibit the growth of gastric cancer cells by promoting apoptosis and autophagy and could be used as a potential agent for treating gastric cancer.

秦皮乙素对人胃癌SGC-7901细胞增殖、迁移、侵袭和糖酵解的影响

目的探讨秦皮乙素(AES)对胃癌SGC-7901细胞增殖、迁移、侵袭和糖酵解的影响及相关机制。方法采用MTT法检测细胞增殖活性;采用划痕实验和Transwell实验检测细胞迁移和侵袭能力;葡萄糖摄取量测定和乳酸含量测定实验检测细胞糖酵解情况;Western blot法检测迁移、侵袭及糖酵解相关蛋白的表达水平。结果AES能够抑制SGC-7901细胞的增殖活力,且这种抑制效果与AES的剂量成正相关。随着AES剂量的梯度增加,SGC-7901细胞的迁移、侵袭及糖酵解能力逐渐降低(P<0.05)。AES可以下调SGC-7901细胞HIF-1α、MMP-2、MMP-9、GLUT1、LDHA蛋白的表达水平(P<0.05)。结论AES对人胃癌SGC-7901细胞增殖活性及迁移、侵袭能力有抑制作用,通过抑制人胃癌SGC-7901细胞的葡萄糖摄取及乳酸生成降低糖酵解水平。AES可能通过影响缺氧诱导因子HIF-1α抑制SGC-7901细胞迁移、侵袭及有氧糖酵解过程。

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

Objective: To 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.Methods: SGC-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.Results: Xanthotoxin 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.Conclusion: Xanthotoxin 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.

白术水提物通过PI3K-Akt-NF-κB通路抑制胃癌SGC-7901细胞的潜在机制

目的:探讨白术(Atractylodes macrocephala)水提物抑制胃癌SGC-7901细胞活性的潜在机制。方法:分别使用蒸馏水(对照)和白术水提物(白术治疗组)灌胃SD大鼠后,采集静脉血后分离其血清、过滤并分别命名为对照组血清(CON-S)和白术组血清(AM-S)。将胃癌SGC7901细胞分为对照组、10%AM-S组和20%AM-S组,其中两个AM-S组细胞分别在相应浓度的AM-S血清中培养24 h,对照组细胞用正常培养基培养相同时间,收取SGC7901细胞和上清液用于进一步分析。使用MTT法检测各组细胞活力,通过商业试剂盒测定乳酸脱氢酶(LDH)、丙二醛(MDA)和超氧化物歧化酶(SOD)的水平,采用ELISA试剂盒检测各组细胞中IL-6和TNF-α的含量,采用WB法评估各组细胞中PI3K-Akt-NF-κB信号通路相关蛋白的表达。结果:10%AM-S组和20%AM-S组的SGC7901胃癌细胞增殖活力相较于对照组分别降低48.9%和53.25%(P<0.05或P<0.01);胃癌细胞上清液中,相较于对照组,10%AM-S组和20%AM-S组LDH水平分别升高29.25%和123%、SOD活性分别升高18%和54.60%、MDA水平分别降低27.8%和40.0%,IL-6水平分别降低15%和17.5%、TNF-α水平分别降低29.71%和40.16%(P<0.05或P<0.01)。相较于对照组,AM-S组中PI3K-AktNF-κB信号相关蛋白的水平显著下降(P<0.05或P<0.01)。结论:白术水提物可以通过抑制癌细胞增殖活力、促进凋亡、抑制肿瘤微环境中的促炎因子分泌以及改变细胞内的氧化应激水平等方式抑制胃癌,其机制可能是通过抑制PI3K-Akt-NF-κB通路来实现这些抗癌作用的。

miR-497阻断Wnt/β-catenin信号通路抑制SGC-7901人胃癌失巢凋亡抵抗细胞的生长和转移

目的 探讨微小RNA 497(miR-497)在胃癌转移中的作用及机制。方法 SGC-7901胃癌亲本细胞培养在超低黏附环境中,重新贴壁后建立SGC-7901细胞失巢凋亡抵抗模型,集落形成实验、流式细胞术、 TranswellTM实验和划痕愈合实验检测其细胞生物学行为与亲本细胞的差异、荧光定量PCR检测miR-497表达、 Western blot法检测无翅基因/β联蛋白(Wnt/β-catenin)信号通路关键蛋白以及上皮间质转化(EMT)相关蛋白如波形蛋白(vimentin)和上皮钙黏蛋白(E-cadherin)等表达的变化;亲本细胞和凋亡抵抗SGC-7901细胞转染miR-497抑制物(miR-497 inhibitor)或miR-497模拟物(miR-497 mimic), CCK-8法检测其增殖活性、 TranswellTM侵袭实验检测细胞侵袭能力、 TranswellTM迁移实验和划痕愈合实验检测细胞迁移能力、 Western blot法检测Wnt1、 β-catenin、 E-cadherin、 vimentin蛋白表达的变化。通过在失巢凋亡抵抗SGC-7901细胞中转染miR-497 mimic,在裸鼠皮下接种,测量并记录肿瘤组织的体积及质量的变化,Western blot法检测Wnt1、 β-catenin、 E-cadherin、 vimentin蛋白表达的变化。结果 与亲本细胞相比,SGC-7901胃癌失巢凋亡抵抗细胞增殖速度更快、集落形成更强,凋亡率更低,侵袭和迁移能力更强,miR-497表达明显下降。下调miR-497后细胞增殖能力显著增强,侵袭、迁移能力明显增强,Wnt1、 β-catenin蛋白表达量显著增加,vimentin表达显著增加,E-cadherin表达下降,而上调miR-497表达结果相反。miR-497过表达组的肿瘤组织生长速度、肿瘤的体积与质量明显低于对照组;Wnt1、 β-catenin、 vimentin蛋白表达量显著下降,而E-cadherin表达明显上调。结论miR-497在SGC-7901失巢凋亡抵抗细胞中低表达,miR-497通过阻断Wnt/β-catenin信号通路的活化和EMT,抑制胃癌细胞的生长和转移。

RRR-α-tocopheryl succinate inhibits human gastric cancer SGC-7901 cell growth by inducing apoptosis and DNA synthesis arrest

AIM:To investigate the effects of growth inhibition ofhuman gastric cancer SGC-7901 cell with RRR-α-tocopherylsuccinate(VES),a derivative of natural Vitamin E,viainducing apoptosis and DNA synthesis arrest.METHODS:Human gastric cancer SGC-7901 cells wereregularly incubated in the presence of VES at 5,10 and20mg.L^(-1)(VES was dissolved in absolute ethanol anddiluted in RPMI 1640 complete condition mediacorrespondingly to a final concentration of VES and lmL.L^(-1)ethanol),succinic acid and ethanol equivalents asvehicle(VEH)control and condition-media only asuntreated(UT)control.Trypan blue dye exclusionanalysis and MTT assay were applied to detect the cellproliferation.37kBq of tritiated thymidine was added tocells and [~3H]TdR uptake was measured to observe DNAsynthesis.Apoptotic morphology was observed byelectron microscopy and DAPI staining.Flow cytometryand terminal deoxynucleotidyl transferase-mediated dUTPnick end labeling(TUNEL)assay were performed to detectVES-triggered apoptosis.RESULTS:VES inhibited SGC-7901 cell growth in a dose-dependent manner.The growth curve showed suppressionby 24.7%,49.2% and 68.7% following 24h of VEStreatment at 5,10 and 20 mg·L^(-1),respectively,similar tothe findings from MTT assay.DNA synthesis wasevidently reduced by 35%,45% and 98% after 24h VEStreatment at 20 mg·L^(-1)and 48h at 10 and 20 mg·L^(-1),respectively.VES induced SGC-7901 cells to undergoapoptosis with typically apoptotic characteristics,including morphological changes of.chromatincondensation,chromatincrescent formation/margination,nucleus fragmentation and apoptotic body formation,typical apoptotic sub-G1 peak by flow cytometry andincrease of apoptotic cells by TUNEL assay in which 90%of cells underwent apoptosis after 48h of VES treatment at20 mg·L^(-1).CONCLUSION:VES can inhibit human gastric cancer SGC-7901 cell growth by inducing apoptosis and DNA synthesisarrest,inhibition of SGC-7901 cell growth by VES is dose-and time-dependent.Therefore VES can function as apotent chemotherapeutic agent against human gastric carcinogenesis.

Heat shock protein 70 antisense oligonucleotide inhibits cell growth and induces apoptosis in human gastric cancer cell line SGC-7901

AIM: Heat shock protein (HSP)70 is over-expressed in human gastric cancer and plays an important role in the progression of this cancer. We investigated the effects of antisense HSP70 oligomer on human gastric cancer cell line SGC-7901, and its potential role in gene therapy for this cancer.METHODS: Human gastric cancer cell line SGC-7901 was treated in vitro with various concentrations of antisense HSP70 oligonucleotides at different intervals. Growth inhibition was determined as percentage by trypan blue dye exclusion test. Extracted DNA was electrophoresed on agarose gel, and distribution of cell cycle and kinetics of apoptosis induction were analyzed by propidium iodide DNA incorporation using flow cytometry, which was also used to detect the effects of antisense oligomer pretreatment on the subsequent apoptosis induced by heat shock in SGC-7901 cells. Proteins were extracted for simultaneous measurement of HSP70 expression level by SDS-PAGE Western blotting.RESULTS: The number of viable cells decreased in a doseand time-dependent manner, and ladder-like patterns of DNA fragments were observed in SGC-7901 cells treated with antisense HSP70 oligomers at a concentration of 10 μmol/L for 48 h or 8 μmol/L for 72 h, which were consistent with inter-nucleosomal DNA fragmentation. Flow cytometric analysis showed a dose- and time-dependent increase in apoptotic rate by HSP70 antisense oligomers. This response was accompanied with a decrease in the percentage of cells in the G1 and S phases of the cell cycle, suggesting inhibition of cell proliferation. In addition, flow cytometry also showed that pretreatment of SGC-7901 cells with HSP70 antisense oligomers enhanced the subsequent apoptosis induced by heat shock treatment. Western blotting demonstrated that HSP70 antisense oligomers inhibited HSP70 expression, which preceded apoptosis, and HSP70 was undetectable at the concentration of 10 μmol/L for 48 h or 8 μmol/L for 72 h.CONCLUSION: Antisense HSP70 oligomers can abrogate HSP70 expression in SGC-7901 cells, which may in turn induce apoptosis and inhibit cell proliferation, conversely suggesting that HSP70 is required for the proliferation and survival of human gastric cancer cells under normal conditions.

Effect of apoptosis on gastric adenocarcinoma cell line SGC-7901 induced by cis-9,trans-11-conjugated linoleic acid

AIM: To determine the effect of apoptosis on gastric cancer cells (SGC-7901) induced by cis-9, trans-11-conjugated linoleic acid (c9, t11-CLA) and its possible mechanism in the inhibition of cancer cells growth.METHODS: Using cell culture, flow cytometery and immunocytochemical techniques, we examined the cell growth, frequency of apoptosis and distribution of cell cycle,expression of ki67, bcl-2, Fas, and c-myc of SGC-7901 cells which were treated with various c9, t11-CLA concentrations (25,50,100 and 200 μmol@L-1) of c9, t11-CLA for 24h and 48 h,with a negative control (0.1% ethanol).RESULTS: The growth of SGC-7901 cells was inhibited by c9,t11-CLA. Eight days after treatment with various concentrations of c9,t11-CLA, as mentioned above, the inhibition rates were 5.9 %, 20.2 %,75.6 % and 82.4 %, respectively. The frequency of apoptosis on SGC-7901 cells induced by different concentrations of c9, t11-CLA (except for 25 μmol@L-1, 24 h) was significantly greater than that in the negative control (P＜0.01). To further investigate the influence of the cell cycle progression, we found that apoptosis induced by c9, t11-CLA may be involved in blocking the cell cycle of SGC-7901 cells. Immunocytochemical staining demonstrated that SGC-7901 cells preincubated in media supplemented with different c9, t11-CLA concentrations for various time periods significantly decreased the expressions of ki67 (the expression rates were 18.70-3.20 %, at 24 h and 8.10-0.20 % at 48 h, respectively), bd-2 (4.30-0.15 % at 24 h and 8.05 %-0 at 48 h),and c-myc(4.85-2.20 % at 24 h and 4.75-0.30 % at 48 h) as compared with those in the controls (the expressions of ki67, bcl-2, and c-mycwere 15.1% at 24 h and 13.5 % at 48 h, 6.80 % at 24 h and 8.00 % at 48 h,5.50 % at 24 h and 5.30 % at 48 h, respectively) (P＜0.01),whereas the expressions of Fas were increased (0.60-2.75 %,24 h and 0.45-5.95 %, 48 h).CONCLUSION: The growth and proliferation of SGC-7901 cells are inhibited by cg, t11-CLA via blocking the cell cycle,pathways of bcl-2-associated mitochondria with reduced expression of bcl-2 and Fas-associated death domain protein (FADD) with enhanced expression of Fas. But expression of c-myc on SGC-7901 cells is lower than that in negative control, which needs to be studied further.

Inhibitory effects of c9, t11-conjugated linoleic acid on invasion of human gastric carcinoma cell line SGC-7901

AIM: To investigate the effect of c9, t1l-conjugated linoleic acid (c9, t11-CLA) on the invasion of human gastric carcinoma cell line and its possible mechanism of preventing metastasis.METHODS: Using reconstituted basement membrane invasion, chemotaxis, adhesion, PAGE substrate zymography and RT-PCR assays, we analyzed the abilities of invasion,direct migration, adhesion of intracellular matrix, as well as the activity of type IV collagenase and expression of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 mRNA in SGC-7901 cells which were treated with gradually increased concentrations (25, 50, 100 and 200μmol/L) of c9,c11-CLA for 24 h.RESULTS: At the concentrations of 200μmol/L, 100μmol/L and 50μmol/L, c9,tll-CLA suppressed the invasion of SGC-7901 cells into the reconstituted basement membrane by 53.7 %, 40.9 % and 29.3 %, respectively, in comparison with the negative control. Only in the 200 μmol/L c9,tll-CLA group, the chemotaxis of SGC-7901 cells was inhibited by 16.0 % in comparision with the negative control. C9,tll-CLA also could inhibit the adhesion of SGC-7901 cells to laminin, fibronectin and Matrigel, increase the expression of TIMP-1 and TIMP-2 mRNA, and reduce type IV collegenase activities in the serum-free medium supernatant of SGC-7901 cells.CONCLUSION: c9,t11-C:LA can inhibit the invasion of SGC-7901 cells at multiple procedures in tumor metastasis cascade, which may be associated with the induction of TIMP-1 and TIMP-2 mRNA expression.

Tributyrin inhibits human gastric cancer SGC-7901 cell growth by inducing apoptosis and DNA synthesis arrest

AIM: To evaluate the effects of tributyrin, a pro-drug of natural butyrate and a neutral short-chain fatty acid triglyceride, on the growth inhibition of human gastric cancer SGC-7901 cell.METHODS: Human gastric cancer SGC-7901 cells were exposed to tributyrin at 0.5, 1, 2, 5, 10 and 50 mmol·L-^1 for 24-72h. MTT assay was applied to detect the cell proliferation.[^3H]-TdR uptake was measured to determine DNA synthesis.Apoptotic morphology was observed by electron microscopy and Hoechst-33258 staining. Flow cytometry and terminal deoxynudeotidyl transferase-mediated dUTP nick end labeling(TUNEL) assay were performed to detect tributyrin-triggered apoptosis. The expressions of PARP, Bcl-2 and Bax were examined by Western blot assay.RESULTS: Tributyrin could initiate growth inhibition of SGC-7901 cell in a dose-and time-dependent manner. [^3H]-TdR uptake by SGC-7901 cells was reduced to 33.6% after 48h treatment with 2mmol·L^-1 tributyrin, compared with the control (P<0.05). Apoptotic morphology was dell:ted by TUNEL assay. Flow cytometry revealed that tributyrin could induce apoptosis of SGC-7901 cells in dose-dependent manner. After 48 hours incubation with tributyrin at 2mmol·L^-1, the level of Bcl-2 protein was lowered, and the level of Bax protein was increased in SGC-7901, accompanied by PARP cleavage.CONCLUSION: Tributyrin could inhibit the growth of gastric cancer cells effectively in vitro by inhibiting DNA synthesis and inducing apoptosis, which was associated with the downregulated Bcl-2 expression and the up-regulated Bax expression. Therefore, tribublrin might be a promising chemopreventive and chemotherapeutic agent against human gastric carcinogenesis.

Effects of mifepristone on proliferation of human gastric adenocarcinoma cell line SGC-7901 in vitro

AIM: To explore the effects of mifepristone, a progesterone receptor (PR) antagonist, on the proliferation of human gastric adenocarcinoma cell line SGC-7 901 in vitro and the possible mechanisms involved.METHODS: In situ hybridization was used to detect the expression of PR mRNA in SGC-7 901 cells. After treatment with various concentrations of mifepristone (2.5, 5, 10,20μmol/L) at various time intervals, the ultrastructural changes, cell proliferation, cell-cycle phase distribution, and the expression of caspase-3 and Bcl-XL were analyzed using transmission electron microscopy (TEM), tetrazolium blue (MTT) assay, ^3H-TdR incorporation, flow cytometry, and reverse transcription-polymerase chain reaction (RT-PCR).RESULTS: Mifepristone markedly induced apoptosis and inhibited cell proliferation of PR- positive SGC-7 901 cells revealed by TEM, MTT assay and ^3H-TdR incorporation, in a dose- and time-dependent manner. The inhibitory rate was increased from 8.98% to 51.29%. Flow cytometric analysis showed mifepristone dose-dependently decreased cells in S and G2/M phases, increased cells in G0/G1 phase,reduced the proliferative index from 57.75% to 22.83%.In addition, mifepristone up-regulated the expression of caspase-3, and down- regulated the Bcl-XL expression,dose-dependently.CONCLUSION: Mifepristone effectively inhibited the proliferation of PR-positive human gastric adenocarcinoma cell line SGC-7 901 in vilrothrough multiple mechanisms, and may be a beneficial agent against human adenocarcinoma.

Inhibition of β-ionone on SGC-7901 cell proliferation and upregulation of metalloproteinases-1 and -2 expression

AIM:To observe the effect of β-ionone on the proliferation of human gastric adenocarcinoma cell line SGC-7901 and the inhibition of metalloproteinase.METHODS:Using growth inhibition, Zymograms assays and reverse transcription-polymerase-chain reaction (RT-PCR),we examined cell growth rates,activities of matrix metalloproteinases-2 (MMP-2) and-9 (MMP-9),and expression of metalloproteinases-1 (TIMP-1) and-2 (TIMP-2) in SGC-7901 cells after the treatment with β-ionone for 24 h and 48h, respectively.RESULTS:β-ionone had an inhibitory effect on the growth of SGC-7901 cells.Eight days after the treatment with β-ionone at concentrations of 25, 50, 100 and 200μmol/L,the inhibition rates were 25.9%, 28.2%, 74.4% and 90.1%,respectively. The IC50 value of β-ionone for SGC-7901 cells was estimated to be 89μmol/L.The effects of β-ionone on MMP-2 and MMP-9 activities in SGC-7901 cells were not observed. However,the levels of TIMP-1 and TIMP-2 transcripts were elevated in cells treated with β-ionone in a dose-dependent manner.CONCLUSION:β-ionone can inhibit the proliferation of SGC-7901 cells,upregulate the expression of TIMP-1 and TIMP-2 expression, and may influence metastasis of cancer.