Gallic acid inhibits cell viability and induces apoptosis in human monocytic cell line U937

In the present study, we investigated the effects of gallic acid (GA) (3,4,5-trihydroxybenzoic acid), a polyhydroxyphenolic compound, isolated from Rhus chinensis, on the human monocytic lymphoma cell line U937. In vitro experiments showed that treating U937 cells with various amounts of GA inhibited cell viability and induced apoptosis in a dose-dependent manner. In order to understand the mechanism by which GA induces apoptosis, we examined the gene expression of p53, nuclear factor κB (NF-κB), and inhibitor of NF-κB (I-κB) after treating the cells with GA and found that expression levels of the genes for p53 and NF-κB increased and that for I-κB decreased. The results obtained from western blotting with U937 cells showed up-regulation of NF-κB protein and down-regulation of proliferating cell nuclear antigen and I-κB protein. These results demonstrate that GA efficiently induces apoptosis in U937 cells and that GA is a potential chemotherapeutic agent against lymphoma.     

Docosahexaenoic acid enhances the antioxidant response of human fibroblasts by upregulating gamma-glutamyl-cysteinyl ligase and glutathione reductase

The chemopreventive effects of dietary n-3 PUFA in various pathologies has so far remained controversial, and we were interested in studying their potential influence on cell redox status. DHA (22 : 6n-3), a typical highly unsaturated n-3 PUFA, was used at 30 micromol/l in a model of human fibroblast cell culture. A dose-response effect, roughly linear, was checked for DHA between 0 and 60 micromol/l, and was accompanied by a large increase in intracellular GSH content. A time course study of this effect shows that, after a short fall, as soon as 4 h after the beginning of the experiment, the large increase in the GSH content was associated with elevated catalytic activities of gamma-glutamyl-cysteinyl ligase, glutathione reductase and glutathione S-transferase. This coordinated response is characteristic of an antioxidant response and was confirmed by the induction of expression of mRNA for gamma-glutamyl-cysteinyl ligase, glutathione reductase and haem-oxygenase. This large increase in the GSH content contributes to decreasing the reactive oxygen species level, as assessed by the decreased accumulation of dichlorofluorescein inside cells. To our knowledge, this is the first report on a specific and potent effect of DHA for decreasing the oxidative stress of human fibroblasts.     

Docosahexaenoic acid and vitamin E can reduce human monocytic U937 cell apoptosis induced by tumor necrosis factor

The effects of polyunsaturated fatty acids and vitamin E on tumor necrosis factor (TNF)-induced apoptosis of human monocytic U937 cells was explored to assess to what extent these nutrients could attenuate apoptosis. Preincubation of U937 cells with arachidonic acid for 24 h did not affect TNF-induced apoptosis. Eicosapentaenoic acid slightly but significantly reduced the proportion of apoptotic cells only when apoptosis was induced by TNF without cycloheximide (CHI). In contrast, preincubation with docosahexaenoic acid (DHA) greatly (40 approximately 70%) attenuated apoptosis induced by stimulation with either TNF or TNF + CHI for 3 h. The inhibition of apoptosis was accompanied by enrichment of DHA in membrane phospholipids, indicating that DHA probably exerted its inhibitory activity after being incorporated into the phospholipids. Vitamin E also played a role as a partial inhibitor of apoptosis 3 h after TNF addition. This vitamin could further reduce the apoptosis of DHA-treated cells, and such an additive effect was obvious when apoptosis was induced at a low frequency. Longer-range stimulation of U937 cells with TNF showed that inhibition of apoptosis by preincubating cells with either DHA or vitamin E was not significant 9 h after TNF addition, but that preincubation with both DHA and vitamin E could reduce the proportion of apoptotic cells even at this time point. Our findings suggested that ingestion of nutrients such as DHA and vitamin E might exert beneficial effects on organ dysfunction associated with various TNF-related diseases.     

小蘗碱诱导人宫颈癌Hela细胞株凋亡的作用

目的:探讨中药黄连素对子宫颈癌Hela细胞株的增殖抑制和诱导凋亡的作用。方法:以不同浓度的黄连素(10、20、40、80μmol/L),分12、24、48、72h四个时间点处理Hela细胞,光镜观察细胞形态变化;用四甲基偶氮唑蓝(MTT)法测定细胞增殖抑制率;用透射电子显微镜及琼脂糖凝胶电泳检测凋亡发生情况。结果:黄连素可抑制Hela细胞增殖,作用呈明显的时效和量效关系,差异有统计学意义(P<0.01);黄连素可诱导Hela细胞凋亡,透射电子显微镜下可见凋亡细胞;琼脂糖凝胶电泳出现细胞凋亡典型的DNA"梯状"条带。结论:黄连素体外对Hela细胞具有增殖抑制作用和促进凋亡作用。     

Docosahexaenoic acid inhibits adipocyte differentiation and induces apoptosis in 3T3-L1 preadipocytes

Docosahexaenoic acid (DHA, C22:6), a (n-3) fatty acid in fish oil, has been shown to decrease body fat and fat accumulation in rodents. We investigated the direct effect of DHA on cell growth, differentiation, apoptosis, and lipolysis using 3T3-L1 adipocytes. Cells were treated with 25-200 mumol/L DHA containing 0.2 mmol/L alpha-tocopherol or bovine serum albumin vehicle as a control. Proliferation of preconfluent preadipocytes was not affected by the DHA treatment. When added to postconfluent preadipocytes, all concentrations of DHA inhibited differentiation-associated mitotic clonal expansion (P < 0.01). Postconfluent preadipocytes demonstrated apoptosis after 48 h with 100 mumol/L DHA and after 24 and 48 h with 200 mumol/L DHA (P < 0.01). Differentiation was examined by Oil Red O staining and glycerol-3-phosphate dehydrogenase (GPDH) activity after DHA treatment for 6 d. DHA decreased mean droplet size and percent lipid area in a dose-dependent manner (P < 0.01). GPDH activity was also decreased by DHA treatment (P < 0.01). In fully differentiated adipocytes, DHA increased basal lipolysis compared with the control (P < 0.01). These results demonstrate that DHA may exert its antiobesity effect by inhibiting differentiation to adipocytes, inducing apoptosis in postconfluent preadipocytes and promoting lipolysis.     

Deoxycholic acid can induce apoptosis in the human colon cancer cell line HCT116 in the absence of Bax

In the human colon cancer cells HCT116, deoxycholic acid (DCA) induces apoptosis via the mitochondrial pathway by triggering the release of mitochondrial factors such as cytochrome c. To elucidate if Bax, a proapoptotic member of the Bcl-2 family known to trigger cytochrome c release in response to various types of apoptotic stimuli, is involved in DCA-induced apoptosis in HCT116 cells, we analyzed DCA-induced apoptosis in Bax-knockout (Bax(-/-)) HCT116 cells. Cytochrome c release and caspase-9 activation were detectable after 5 min in both Bax(-/-) and Bax(+/-) HCT116 cells. Caspase-3 and caspase-8 activation was observed after 15 and 30 min, respectively. Bax(-/-) cells were protected from apoptosis by treating them with ursodeoxycholic acid for 12 h prior to DCA treatment. These results are consistent with our previous observations that were obtained by using wild-type HCT116 cells and suggest that Bax is not indispensable for DCA-induced apoptosis in HCT116 cells.     

硒与氟对人肝细胞凋亡和脂质过氧化的影响

目的　研究硒、氟对离体培养的人肝细胞凋亡和脂质过氧化的影响。方法　体外培养的人肝细胞分别接触一定剂量的氟和 /或硒 1 2h后 ,检测肝细胞凋亡小体百分率、细胞周期构成比、还原型谷胱甘肽 (GSH)含量和脂质过氧化物 (LPO)的水平以及培养液中LPO和乳酸脱氢酶 (LDH)、丙氨酸转氨酶 (ALT)和天冬氨酸转氨酶 (AST)的活性。结果　加氟组肝细胞凋亡小体百分率 (1 5 557±2 0 56) % ,S期细胞数 (4 82 3± 0 454) % ,肝组织和培养液中LPO水平 [分别为 (2 884± 0 589)和 (3 547± 0 561 )nmol/LMDA/mg prot) ,培养液中AST和LDH含量 (分别为 91 1± 36 4和 1 4 0 4± 7 6U/L) ,均明显高于对照组 [分别为 (1 0 31 3± 1 0 2 3) % ,(3 2 53± 0 743) % ,(1 473± 0 40 1 )nmol/LMDA/mg ,(1 694± 0 443)nmol/LMDA/mg,(54 5± 3 2 )U/L和 (1 2 6 4± 2 6)U/L] ,而氟组肝组织GSH含量则明显低于对照组 [分别为 (4 2 2 5± 0 781 ) μg/mg和 (7 595± 1 0 4 2 ) μg/mg) ;硒可通过升高GSH含量 ,降低LPO、AST、LDH水平和凋亡小体百分率而拮抗氟产生的毒性作用。结论　一定剂量的硒可拮抗氟所诱导的肝细胞凋亡和脂质过氧化     

Ascorbic acid enhances radiation-induced apoptosis in an HL60 human leukemia cell line

This study was conducted to examine the utility of the combined use of ascorbic acid (AsA) and radiation in clinical applications. We investigated cell survival, DNA fragmentation, and caspase activation after X-ray irradiation and AsA treatment of human leukemia HL60 cells. The number of living cells decreased after combined X-ray irradiation and AsA treatment (2 Gy + 5 mM) in comparison with that after X-ray irradiation (2 Gy) or AsA treatment (5 mM) alone. DNA fragmentation was more in the cells subjected to combined X-ray irradiation and AsA treatment than in those subjected to X-ray irradiation alone. Caspase-3, caspase-8, and caspase-9 were highly activated following combined X-ray irradiation and AsA treatment, but caspase-8 activity was not markedly increased after X-ray irradiation alone. Bax levels in the mitochondrial membrane fractions were increased after AsA treatment alone and after combined X-ray irradiation and AsA treatment. However, there was no apparent increase in the Bax levels after X-ray irradiation treatment alone. Thus, this study confirmed that supplementing X-ray irradiation with AsA treatment results in increased apoptosis in HL60 cells. With regard to the apoptosis-inducing factors, we hypothesized that Bax and caspase-8 were activated after combined X-ray irradiation and AsA treatment compared with either treatment alone.     

ω-3多不饱和脂肪酸廿烷五烯酸单剂以及联合卡铂对人肺腺癌A-549细胞系增殖和凋亡的影响

目的观察廿烷五烯酸（EPA）单剂以及与卡铂联合应用对人肺腺癌A-549细胞系增殖和凋亡的影响。方法分别用100μg／ml卡铂、80μg／mlEPA以及100μg／ml卡铂联合80μg／mlEPA孵育A-549细胞48h后,采用MTr法检测药物对h-549细胞增殖的抑制率,HE染色观察细胞形态学,流式细胞术定量分析细胞凋亡率。结果100μg／ml卡铂联合80μg／mlEPA对A-549细胞系的增殖抑制率为85．20％±5．00％,显著高于80μg／mlEPA（32．85％±3．00％,P=0．0001）或100μg／ml卡铂（53．25％±3．00％,P=0．0013）单独的作用。HE染色显示：药物干预后部分A-549细胞出现凋亡形态学改变。卡铂联合EPA组A-549细胞凋亡率为17．05％4-4．00％,显著高于单用卡铂组（9．49％±1．00％,P20．0252）。结论EPA可能具有增强卡铂抑制人肺腺癌A-549细胞系增殖、促进A-549细胞系凋亡的作用。     

Incorporation of branched-chain fatty acid into cellular lipids and caspase-independent apoptosis in human breast cancer cell line,SKBR-3

Background  

13-Methyltetradecanoic acid (13-MTD), an iso-C15 branched- chain saturated fatty acid, has been shown to induce apoptotic cell death of numerous human cancer cells. However, the mechanism for the induction of apoptosis has not been fully understood. This study described the incorporation of 13-MTD into cellular lipid of SKBR-3 breast cancer cells and apoptosis related event to gain more insight into the mechanism action of this fatty acid.     

二十碳五烯酸联合依托泊苷对人肺腺癌A-549细胞增殖和凋亡的影响

目的 研究二十碳五烯酸(EPA)联合依托泊苷对人肺腺癌A-549细胞株增殖与凋亡的影响.方法 分别用终浓度为40 μg/ml EPA、10 μg/ml依托泊苷、40 μg/ml EPA+ 10μg/ml依托泊苷、20μg/ml依托泊苷、40 μg/ml EPA+ 20μg/ml依托泊苷孵育A-549细胞,采用MTT法、膜联蛋白V-异硫氰酸荧光素/碘化丙锭双染法、吖啶橙/溴化乙锭双染法及流式细胞术研究细胞增殖抑制率、细胞形态学及凋亡情况.结果 EPA联合依托泊苷对A-549细胞的增殖抑制率显著高于依托泊苷单独的作用(P均＜0.05).细胞荧光染色显示:EPA联合依托白苷组的凋亡细胞数量多于依托泊苷单独作用组.EPA联合依托泊苷组的S期及G2/M期细胞显著多于依托泊苷单独作用的细胞(P均＜0.05).结论 EPA可能具有增强依托泊苷抑制人肺腺癌A-549细胞增殖、促进A-549细胞凋亡的作用.     

Apoptosis in human pancreatic cancer cells induced by eicosapentaenoic acid

OBJECTIVES: Clinical studies have shown that administration of eicosapentaenoic acid (EPA) to patients who have unresectable pancreatic cancer induces marked attenuation of cachexia. However, the exact mechanisms of the beneficial effect of EPA on pancreatic cancer are unknown. This examined the effect of EPA on proliferation of human pancreatic cancer cell lines and sought to clarify its mechanisms. METHODS: The effects of EPA on proliferation of three human pancreatic cancer cell lines (SW1990, AsPC-1, and PANC-1) were assessed. Induction of apoptosis and expressions of apoptosis-related proteins were measured. The effect of EPA on cyclo-oxygenase-2 expression in these cell lines was determined. RESULTS: EPA inhibited proliferation of all three human pancreatic cancer cell lines in a dose-dependent fashion. Simultaneously, EPA treatment induced apoptosis and this was associated with caspase-3 activation. EPA treatment was also associated with a decrease in intracellular levels of cyclo-oxygenase-2 protein. CONCLUSION: We have demonstrated that EPA inhibits human pancreatic cancer cell growth due at least in part to the induction of apoptotic cell death. Such apoptosis is associated with activation of caspase-3 and suppression of cyclo-oxygenase-2 expression. Greater understanding of the molecular events associated with the biological activity of EPA should enhance the therapeutic potential of administration of EPA to patients who have pancreatic cancer.     

氟对肾脂质过氧化和细胞凋亡时间与剂量效应的研究

目的阐明饮水氟含量与肾脏脂质过氧化和细胞凋亡的时间效应和剂量效应关系,初步探讨二者在氟中毒肾损伤发生、发展过程中的作用。方法在饮水中加入不同剂量的氟化钠喂饲大鼠60、90、120 d后,检测肾脏细胞中MDA含量及细胞凋亡水平。结果 90 d高氟组和120 d中、高氟组MDA含量较相同时间对照组显著升高,且氟致肾脏中MDA含量增高呈明显剂量-效应和时间-效应关系;不同染毒时间下,低、中、高剂量氟诱导肾脏细胞凋亡与相同时间对照组比较差异无统计学意义。同一剂量下,不同剂量组间肾脏中MDA含量和细胞凋亡水平未见显著性差异。结论过量氟可导致机体脂质过氧化作用增强,在120 d染氟周期,一定剂量氟不能诱导肾脏发生病理性凋亡,因此,脂质过氧化是氟中毒肾损伤的始动环节,且氟致肾脏损害很可能是继发于氟作用于DNA损伤检查点中的关键分子来达成。     

紫杉醇诱导胰腺癌细胞凋亡Survivin表达的变化及意义

目的 研究紫杉醇(PA)体外化疗对胰腺癌细胞凋亡抑制蛋白Survivin基因表达的影响.方法 培养人胰腺癌细胞株SW1990,加入低浓度的PA,用流式细胞仪分别检测加药前和加药后24、48 h的细胞凋亡率,用逆转录-聚合酶链反应(RT-PCR)和免疫印迹技术(Western blot)检测Survivin mRNA和蛋白的表达.结果 SW1990细胞给予低浓度的PA后,加药前和加药后24、48 h的细胞凋亡率分别为(2.59±0.35)%、(14.75±1.29)%、(22.65±2.80)%;其Survivin mRNA的表达则分别比加药前提高了1.1倍和2.9倍;Survivin蛋白的表达分别增加了1.3倍和3.6倍.结论 应用PA化疗可促使胰腺癌细胞内Survivin表达的增加,抵抗化疗诱导的细胞凋亡.     

紫杉醇诱导胰腺癌细胞凋亡Survivin表达的变化及意义

目的研究紫杉醇（PA）体外化疗对胰腺癌细胞凋亡抑制蛋白Survivin基因表达的影响。方法培养人胰腺癌细胞株SW1990，加入低浓度的PA，用流式细胞仪分别检测加药前和加药后24、48h的细胞凋亡率，用逆转录-聚合酶链反应（RT-PCR）和免疫印迹技术（Western blot）检测Survivin mRNA和蛋白的表达。结果SW1990细胞给予低浓度的PA后，加药前和加药后24、48h的细胞凋亡率分别为（2．59±0．35）％、（14．75±1．29）％、（22．65±2．80）％；其Survivin mRNA的表达则分别比加药前提高了1．1倍和2．9倍；Survivin蛋白的表达分别增加了1．3倍和3．6倍。结论应用PA化疗可促使胰腺癌细胞内Survivin表达的增加，抵抗化疗诱导的细胞凋亡。     

正己烷致大鼠过氧化损伤及肝细胞凋亡的实验研究

目的研究正己烷(n-hexane)对大鼠的脂质过氧化损伤和肝细胞凋亡的影响。方法40只雄性SD大鼠随机分成5组,即阴性对照组、染毒组(75、150、300 mg/kg)和阳性对照组(环磷酰胺),每组8只。经腹腔注射染毒4周后,检测肝组织匀浆超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)的活力,血清还原型谷胱甘肽(GSH)和丙二醛(MDA)含量;用流式细胞仪检测肝细胞凋亡情况。结果随着染毒剂量的增加,肝组织匀浆中SOD、GSH-Px活力、血清GSH含量降低,而血清MDA含量增大,组间比较差异有统计学意义(P<0.05或P<0.01),流式细胞仪检测结果显示,肝细胞凋亡率(AV /PI-)组间比较差异有统计学意义(P<0.01),与染毒剂量作相关分析,相关系数为0.913,无明显的相关性(P>0.05)。结论正己烷可引起或增强机体氧自由基反应,导致脂质过氧化损伤,引起肝细胞凋亡和坏死。     

氟致雄性SD大鼠肝脏脂质过氧化及细胞凋亡的时间与剂量效应研究

目的探讨不同染氟剂量和不同染氟时间对雄性SD大鼠肝脏脂质过氧化和细胞凋亡的影响。方法 SPF级健康雄性SD大鼠60只,随机分为3批(分别染氟60、90、120 d),每批再随机分为对照组、低、中和高氟组,每组5只,分别自由饮用浓度为0、10、50、100 mg/L的氟化钠水溶液。染氟到期后,采用硫代巴比妥酸(TBA)法和流式细胞技术(FCM)分别检测实验动物肝脏MDA含量及细胞凋亡水平。结果与对照组相比,染氟时间相同时,60、90和120 d中氟组和高氟组大鼠肝脏MDA含量均显著升高(P0.05),肝脏MDA含量与染氟剂量之间的Pearson相关系数r1依次为0.98、0.99、0.98(P0.01),呈高度正相关;染氟剂量相同时,大鼠肝脏MDA含量与染氟时间之间的Pearson相关系数r2分别为0.98、0.95、0.89(P0.05),呈正相关。与对照组比较,染氟时间相同时,60 d高氟组和90 d低、中、高氟组肝脏细胞凋亡率明显升高(P0.05),肝脏细胞凋亡率与染氟剂量之间的Pearson相关系数r1分别为0.97、0.81、0.94(P0.05),肝脏细胞凋亡率随染氟剂量增加有逐渐升高趋势;同一染氟剂量下,肝脏细胞凋亡率与染氟时间之间的Pearson相关系数r2分别为-0.71、-0.81、-0.97(P0.05),随染氟时间的延长,肝脏细胞凋亡率呈逐步下降趋势。结论氟致雄性SD大鼠肝脏的脂质过氧化较为稳定;而所致的肝脏细胞凋亡改变较为复杂,可能受较多的因素调控。     

化疗诱导胰腺癌细胞凋亡survivin mRNA表达的变化的研究

目的研究紫杉醇体外化疗对胰腺癌细胞凋亡抑制蛋白Survivin基因表达的影响。方法培养人胰腺癌细胞株SW1990,加入不同浓度的紫杉醇(PA),在各时间段MTT法测细胞抑制率,根据结果选择低浓度的PA,分别在加药后24 h、48 h、72h用流式细胞仪检测细胞凋亡率和PT-PCR检测survivin mRNA表达。结果SW1990胰腺癌的抑制率随着紫杉醇的药物浓度和作用时间的增加而增高。给予低浓度的PA诱导后,在加药后24 h、48 h和72 h胰腺癌细胞凋亡率分别是(14.73±1.09)%,(18.36±0.86)%,(23.85±0.96)%;其survivin mRNA则分别提高了1.1倍、2.6倍和4.1倍。结论紫杉醇化疗可促使胰腺癌细胞内Survivin的表达增加,抵抗化疗诱导的细胞凋亡。