17-羟-岩大戟内酯B对U251细胞增殖及凋亡作用的影响

目的:探讨17-羟-岩大戟内酯B(HJB)对人脑胶质瘤细胞U251增殖及凋亡的影响.方法:将U251细胞分为空白对照组,5-氟尿嘧啶组( 80μmol·L-1),HJB组(6.25,12.5,25,50,100,200,400,800μmol· L-).用不同浓度的药物作用24h及药物半数抑制浓度(IC50)浓度作用不同时间(12,24,48,72 h),四甲基偶氮唑蓝(MTT)法检测细胞活性,流式细胞仪Annexin V-FITC/PI检测细胞凋亡率,分光光度法检测半胱氨酸蛋白酶-3(Caspase-3)和半胱氨酸蛋白酶-9(Caspase-9)的相对活性.结果:与空白对照组相比,HJB对U251细胞的增殖有显著抑制作用,并呈浓度依赖及时间依赖性(P＜0.05),作用24 h后IC50为62.236 11μmol·L-1.HJB可诱导U251细胞凋亡,浓度30,60,120μmol· L-1分别处理细胞24 h后,早期凋亡率明显升高(P＜0.05),且呈浓度依赖关系;Caspase-3及Caspase-9的相对活性均升高(P＜0.05),并呈浓度依赖关系.结论:HJB明显抑制体外U251细胞生长并诱导其凋亡,线粒体途径可能是诱导其凋亡的机制之一.     

人参皂苷Rd抑制人脑胶质瘤U251细胞增殖机制研究

目的:体外研究人参皂苷Rd(GS-Rd)抑制人脑胶质瘤U251细胞增殖机制。方法:采用MTT法检测GS-Rd对U251细胞增殖情况的影响;采用流式细胞仪观察GS-Rd对U251细胞周期及凋亡影响;通过实时荧光定量PCR检测GS-Rd对U251细胞相关凋亡基因表达的影响。结果:1)GS-Rd在浓度为20~80μmol/L范围内对U251细胞均有一定的抑制作用,并且抑制强度随药物浓度的增加而增大,呈剂量依赖性;2)GS-Rd各剂量组均可诱导U251细胞凋亡。细胞周期分析显示随着给药浓度增加,越多的U251细胞被阻滞在G1/G0期,使进入S和G2/M期的细胞减少;3)与空白对照组相比,GS-Rd各剂量组Bcl-2 mRNA表达显著降低(P0.05),同时Caspase-3 mRNA表达显著提高(P0.05)。结论:人参皂苷Rd能抑制人脑胶质瘤U251细胞增殖,同时能诱导细胞凋亡,其抑瘤机制可能与下调Bcl-2 mRNA表达和上调Caspase-3 mRNA表达有关。     

麦门冬汤加减联合顺铂对A549细胞化疗增敏的作用机制

目的:通过体外实验观察麦门冬汤加减(modified Maimendong Tang)联合顺铂(cisplatin)对人肺腺癌A549细胞增殖,凋亡及侵袭转移能力及对半胱氨酸蛋白酶-3(Caspase-3),表皮生长因子受体(epidermal growth factor receptor,EGFR)的蛋白表达量的影响,探讨麦门冬汤加减方化疗增敏的作用并研究其相关机制。方法:分别用麦门冬汤加减(15 g·L-1),顺铂(9 mg·L-1),联合药物干预肺腺癌A549细胞,实验分为空白组、麦门冬汤加减组、顺铂组、麦门冬汤加减+顺铂组。利用噻唑蓝(MTT)比色法检测不同质量浓度(0,5,10,15,20,25 g·L-1)麦门冬汤加减和不同质量浓度(0,3,6,9,12,15 mg·L-1)顺铂干预A549细胞24,48,72 h后的增殖能力,检测各组A549细胞的增殖能力;流式细胞术分析各组的凋亡程度及周期的变化;划痕实验和transwell小室实验检测各组的侵袭转移能力;蛋白免疫印迹法检测各组Caspase-3,EGFR蛋白表达的变化情况。结果:与空白组比较,麦门冬汤加减,顺铂干预A549细胞后呈浓度依赖性、时间依赖性抑制细胞的增殖(P0.05);各药物组均能抑制A549细胞增殖能力,减弱划痕愈合能力,减少穿过transwell小室的细胞,促进细胞凋亡,下调Caspase-3,EGFR蛋白表达(P0.05)。与单独给药组比较,麦门冬汤加减与顺铂联合应用后更能明显抑制肺腺癌A549细胞增殖能力和更能诱导A549细胞的凋亡,G0/G1期的细胞增多更明显,S期的细胞明显减少(P0.05);联合用药后,细胞划痕愈合能力明显减弱,穿过transwell小室的细胞明显减少,Caspase-3,EGFR的蛋白表达量下降更明显(P0.05)。结论:麦门冬汤加减与顺铂合用后抑制肺癌细胞A549增殖及侵袭转移能力,诱导细胞凋亡,两者存在协同增敏作用,其相关机制可能与下调Caspase-3,EGFR的蛋白表达相关。     

α-常春藤皂苷抗肿瘤作用机制研究

目的探讨α-常春藤皂苷(BD)对人脑胶质母细胞瘤细胞U251抗肿瘤的作用机制。方法MTT法、集落形成、吉姆萨染色检测不同浓度BD对U251细胞增殖影响;Hochest33342观察细胞凋亡形态变化;流式细胞术检测细胞凋亡;Western Blot检测Bcl-2、Caspase-3蛋白凋亡变化。结果BD可以明显抑制U251的增殖,其抑制作用呈明显的时间、剂量依赖关系。在给药24h后,呈强蓝色荧光,并且细胞在BD18.75,25.00μmol·L-1出现显著凋亡,下调Bcl-2,Caspase-3蛋白表达。结论BD能显著地抑制U251细胞的增殖、诱导细胞凋亡,其作用机制可能与线粒体凋亡有关。     

甘草查尔酮B诱导小鼠黑色素瘤细胞凋亡作用

目的:研究甘草查尔酮B(licochalcone B)诱导小鼠黑色素瘤细胞(B16F0)凋亡作用并初步探讨其机制.方法:取对数生长期B16F0细胞按5 000个/孔接种于96孔板中,MTT染色法检测甘草查尔酮B(5,7.5,10,12.5,15 mg·L-1)作用24 h后,对B16F0细胞的增殖抑制作用;取对数生长期B16F0细胞按1×105个/孔接种于6孔板中,甘草查尔酮B(7.5,15mg·L-1)作用24 h后,Hoeehst 33258染色法观察细胞凋亡形态;取对数生长期B16F0细胞按5×105个/瓶接种于细胞培养瓶中,甘草查尔酮B(5,7.5,10,12.5 mg·L-1)作用24 h后,流式细胞仪检测细胞凋亡率;RT-PCR法检测与凋亡相关基因Bcl-2相关X蛋白(Bax),B淋巴细胞瘤-2(Bcl-2) mRNA表达;荧光法检测半胱氨酸蛋白酶蛋白9(Caspase-9)和半胱胺酸蛋白酶蛋白3(Caspase-3)相对活性.结果:甘草查尔酮B能有效抑制B16F0细胞增殖,作用24 h后对细胞的生长有明显的抑制作用,IC.011.3 mg·L-1,在5～15 mg·L-1表现出明显的剂量依赖,细胞出现明显凋亡特征,随甘草查尔酮B浓度的增加凋亡率逐渐升高;甘草查尔酮B(10,12.5 mg·L-1)能明显下调Bcl-2/Bax,上调Caspase-3,Caspase-9的表达,其中7.5 mg·L-1甘草查尔酮B引起Caspase-9,Caspase-3的活化程度较12.5 mg·L-1高.结论:甘草查尔酮B可能通过激活线粒体调控的凋亡通路诱导B16F0细胞凋亡.     

白藜芦醇抑制人脑胶质瘤U251细胞增殖及诱导其凋亡的实验研究

目的研究白藜芦醇对人脑胶质瘤细胞U251细胞生长抑制及诱导细胞凋亡的作用。方法采用MTT法检测白藜芦醇对U251细胞的增殖活性的影响,采用流式细胞仪检测白藜芦醇对U251细胞早期、晚期凋亡率的影响,用倒置显微镜观察不同浓度的白藜芦醇作用后U251细胞的形态学改变。结果白藜芦醇对U251脑胶质瘤生长有抑制作用,且具时间及剂量依赖性;白藜芦醇能诱导U251细胞早、晚期凋亡,且具时间及剂量依赖性。结论白藜芦醇能抑制U251脑胶质瘤的增殖并能诱导细胞凋亡。     

五味子多糖对人脑胶质瘤U251细胞增殖的抑制作用及机制研究

目的探讨五味子多糖对人脑胶质瘤U251细胞体外生长的抑制作用及诱导细胞凋亡的作用机制。方法实验分为4组,对照组常规培养(不加任何药物)人脑胶质瘤U251细胞,五味子多糖250μg/mL、500μg/mL、800μg/mL组分别加入相应浓度的五味子多糖培养人脑胶质瘤U251细胞。采用MTT法检测各组细胞培养12,24,48 h后生长抑制率;Transwell细胞体外侵袭实验法使细胞穿过小室透膜数量,检测各组细胞迁移能力;流式细胞实验结合AnnexinV-FITC/PI双染色法检测各组细胞培养12,24,48 h后早期凋亡百分比。RT-PCR技术检测500μg/mL五味子多糖作用U251细胞12,24,48 h后bcl-2、bax、caspase-3基因表达水平。结果与对照组比较,不同浓度五味子多糖对U251细胞有显著增殖抑制作用(P均0.05),且抑制作用呈现剂量与时间效应关系;与对照组比较,五味子多糖各组细胞迁移抑制率、细胞早期凋亡率、细胞晚期凋亡率均明显增高(P均0.05),且细胞迁移抑制率和细胞凋亡率随五味子多糖浓度增高而增高(P均0.05)。500μg/mL五味子多糖作用U251细胞12,24,48 h后,Bax、Caspase-3基因表达水平及Bax/Bcl-2比值逐渐增高,Bcl-2基因表达水平逐渐降低,与对照组比较差异均有统计学意义(P均0.05)。结论五味子多糖能显著抑制人脑胶质瘤U251细胞生长,诱导细胞凋亡,降低细胞迁移能力,其促进凋亡作用机制可能与上调Bax、Caspase-3基因表达水平,下调Bcl-2基因表达水平相关。     

17-羟-岩大戟内酯B对K562细胞增殖及凋亡的影响

目的:探讨17-羟-岩大戟内酯B(HJB)对人白血病K562细胞增殖及凋亡的影响.方法:将K562细胞分为3组,分别为:空白对照组,5-氟脲嘧啶组(浓度为100μmol·L-1),HJB组(浓度为6.25,12.5,25,50,100,200,400μmol·L-1).用不同浓度的药物作用24 h和200 μmol·L-1的HJB浓度作用不同时间(12,24,48 h),四甲基偶氮唑蓝(MTT)法检测细胞活性,并与空白对照组和5-氟脲嘧啶组作对比;流式细胞仪Annexin V-FITC/PI检测细胞凋亡率;分光光度法检测半胱氨酸蛋白酶-3(Caspase-3)和半胱氨酸蛋白酶-8(Caspase-8)的相对活性.结果:与空白对照组相比,HJB对K562细胞的增殖有显著性抑制作用,并呈浓度依赖关系及时间依赖关系(P＜0.05),作用24 h后IC50为158.7μmol·L-1.HJB可诱导K562细胞凋亡,用50,100,200 μmol·L-药物分别处理细胞24h后,早期凋亡率较空白组明显升高(P＜0.05),且呈浓度依赖关系;Caspase-3及Caspase8的相对活性均较空白对照组升高(P＜0.05),并呈浓度依赖关系.结论:HJB明显抑制体外K562细胞生长并诱导其发生凋亡,且死亡受体途径可能是诱导其凋亡的一个机制.     

橙皮素通过激活内质网应激C/EBP同源蛋白诱导人神经胶质瘤细胞凋亡实验研究

目的:分析橙皮素(HES)对人神经胶质瘤细胞凋亡的影响及相关分子机制。方法:将人神经胶质瘤U251细胞分为100 μmol/L橙皮素组、200 μmol/L橙皮素组、400 μmol/L橙皮素组、600 μmol/L橙皮素组、800 μmol/L橙皮素组、阴性对照组、4-苯基丁酸(4-PBA)组、橙皮素加4-苯基丁酸组、转染对照组、C/EBP同源蛋白(CHOP)低表达组、橙皮素加转染对照组、橙皮素加CHOP低表达组。采用CCK-8法检测细胞增殖活性,Hoechst 33258染色法和Annexin V/PI双染法检测细胞凋亡率,qRT-PCR法检测CHOP mRNA表达水平,Western blot法检测细胞凋亡蛋白和内质网应激(ERS)蛋白表达水平。结果:HES对胶质瘤U251细胞的增殖抑制作用呈剂量和时间依赖性,与阴性对照组比较,HES可诱导U251细胞凋亡,上调Caspase-3、剪切Caspase-3、多聚ADP核糖聚合酶(PARP)、剪切PARP蛋白以及CHOP、ERS蛋白分子伴侣葡萄糖调节蛋白78、X盒结合蛋白1(XBP-1)、激活转录因子6蛋白表达量和磷酸化真核起始因子2α/eIF2α。4-PBA可逆转HES引起的ERS蛋白和凋亡蛋白表达变化; 干扰CHOP表达可逆转HES对凋亡蛋白的调控作用。结论:HES通过介导ERS途径CHOP诱导胶质瘤细胞凋亡。     

金丝桃苷对耐长春新碱结肠癌HCT8/VCR细胞耐药逆转作用

目的:探讨金丝桃苷对耐长春新碱结肠癌HCT8/VCR细胞的耐药逆转作用及其可能的作用机制。方法:分别以不同质量浓度(2.5~80 mg·L-1)的金丝桃苷及不同质量浓度(1.25~40 mg·L-1)的长春新碱作用于体外培养的HCT8和HCT8/VCR细胞48 h,采用噻唑蓝(MTT)比色法测定细胞生长抑制率,计算各组细胞金丝桃苷和长春新碱的半数抑制浓度(IC50)及金丝桃苷抑制率为5%的药物浓度;采用非毒性剂量金丝桃苷分别与不同质量浓度(1.25~40 mg·L-1)的长春新碱联合作用HCT8/VCR细胞,检测长春新碱的IC50,计算逆转倍数;采用流式细胞仪检测细胞凋亡率及线粒体膜电位变化,比色法检测含半胱氨酸的天冬氨酸蛋白水解酶(Caspase)-3,Caspase-9蛋白活性的变化。结果:金丝桃苷非细胞毒性剂量为0.82mg·L-1。0.82 mg·L-1金丝桃苷可使长春新碱对HCT8/VCR细胞的IC50从65.97 mg·L-1下降至9.94 mg·L-1,逆转倍数为6.63;与单独用长春新碱组比较,长春新碱与金丝桃苷联合用药组细胞凋亡率,Caspase-3,Caspase-9蛋白活性均显著提高(P0.01)。线粒体膜电位检测发现,与单独用长春新碱组及金丝桃苷组比较,长春新碱与金丝桃苷联合用药组低荧光强度相对细胞数所占比率显著提高(P0.01)。结论:长春新碱与金丝桃苷联合应用后可增强Caspase-3,Caspase-9蛋白活性,降低线粒体膜电位,提高HCT8/VCR细胞的凋亡率,从而产生耐药逆转作用。     

Induction of apoptosis in human hepatocarcinoma SMMC-7721 cells in vitro by flavonoids from Astragalus complanatus

Aim of the study

Flavonoids extracted from the seeds of Astragalus complanatus R.Br. reduce the proliferation of many cancer cells. The present study was carried out to evaluate the effects of these flavonoids from Astragalus complanatus (FAC) on human hepatocarcinoma cell viability and apoptosis and to investigate its mechanisms of action in SMMC-7721 cells.

Materials and methods

Cell viability was measured using the MTT assay. To detect apoptotic cells, SMMC-7721 cells treated with FAC were stained with Hoechst 33258 and subjected to agarose gel electrophoresis. Quantitative detection of apoptotic cells was performed by flow cytometry. The effects of FAC on apoptosis and cell cycle regulatory genes and proteins in SMMC-7721 cells were examined using an S series apoptosis and cell cycle gene array and Western blot analysis.

Results

The growth of SMMC-7721 and HepG2 cells was inhibited by treatment with FAC. Cell death induced by FAC was characterized by nuclear condensation and DNA fragmentation. Moreover, the cell cycle was arrested in the G0/G1 and S phases in FAC-treated SMMC-7721 cells. A sub-G1 peak with reduced DNA content was also formed. The activity of caspase-3 was significantly increased following FAC treatment. Microarray data indicated that the expression levels of 76 genes were changed in SMMC-7721 cells treated with FAC: 35 genes were up-regulated and 41 were down-regulated. Western blot analysis showed that caspase-3, caspase-8, Bax, P21, and P27 protein levels in SMMC-7721 cells were increased after 48 h of FAC treatment, while cyclinB1, cyclinD1, CDK1, and CDK4 protein levels were decreased.

Conclusions

These results suggest that FAC may play an important role in tumor growth suppression by inducing apoptosis in human hepatocarcinoma cells via mitochondria-dependent and death receptor-dependent apoptotic pathways.     

Investigation of Ehrlich ascites tumor cell death mechanisms induced by Synadenium umbellatum Pax

Ethnopharmacological relevance

Synadenium umbellatum Pax. is widely found in South America and empirically used in Brazil for the treatment of several diseases, mainly cancer. The aim of the study was to investigate cell death mechanisms induced by Synadenium umbellatum Pax. using Ehrlich ascites tumor (EAT) cells, as well as the myelotoxicity potential of this plant.

Materials and methods

S. umbellatum cytotoxicity was evaluated in EAT cells by trypan blue exclusion and MTT reduction test and the mechanisms involved in EAT cell death were investigated by light and fluorescence microscopy, flow cytometry and immunocytochemistry. Investigation of S. umbellatum myelotoxicity was performed by clonogenic assay of colony forming unit- granulocyte macrophage (CFU-GM).

Results and Conclusion

Our results demonstrated that S. umbellatum decreased the viability of EAT cells using both methods. Morphological analyses revealed that S. umbellatum-treatment induced EAT cell death by apoptotic pathway. We demonstrated the occurrence of reactive oxygen species (ROS) overgeneration, increased intracellular Ca²⁺ concentration, alteration in mitochondrial membrane potential, phosphatydylserine externalization, and activation of caspases 3, 8, and 9. However, S. umbellatum produced myelotoxicity in bone marrow cells in a concentration-dependent manner. In comparison to EAT cells, the effects of S. umbellatum in bone marrow cells were 8-fold lower. Taken together, our results showed that S. umbellatum induced apoptosis in EAT cells at several levels and seems more toxic to tumor cells than to normal bone marrow cells.     

人参皂苷Rg3诱导膀胱癌细胞系EJ的凋亡作用

目的：探讨Rg3抑制膀胱癌细胞的作用及其诱导凋亡的机制。方法：用一定质量浓度的Rg3 处理膀胱癌细胞系EJ细胞,MTT法检测细胞增殖活力和抑制率50%的时候药物的浓度(IC₅₀)；Hoechst33258荧光染色观察凋亡细胞的形态；流式细胞仪分析细胞周期及细胞凋亡率；免疫细胞化学观察caspase-3的表达变化；琼脂糖凝胶电泳测定DNA梯状带。结果：Rg3抑制EJ细胞生长,呈浓度依赖关系,Rg3处理细胞48 h的IC₅₀为125.5 mg·L^-1；经150 mg·L^-1Rg3处理细胞24 h和48 h后,观察到典型的凋亡细胞形态,即染色质凝集、核片段化、凋亡小体、核内致密的颗粒状荧光及caspase-3的表达增加；并呈时效依赖关系；用75 mg·L^-1Rg3处理细胞24,48,150 mg·L^-1的Rg3处理细胞48 h后,Rg3诱导了细胞凋亡和调节细胞周期,S期和G₂/M期的细胞比率增加,G₀/G₁的细胞比率下降；凋亡率从对照组的(1.05±0.17)%分别上升到(8.41±0.98)%,(18.57±2.20)% 和(33.98±1.64)%,琼脂糖凝胶电泳检测出典型的DNA梯形条带,其效应随药物浓度的增加和作用时间的延长而增强。结论：Rg3可通过诱导EJ细胞凋亡而发挥其抑制细胞增殖的作用。     

Hexane extract from Polygonum multiflorum attenuates glutamate-induced apoptosis in primary cultured cortical neurons

Ethnopharmacological relevance

Polygonum multiflorum has traditionally had wide use as an anti-aging treatment in East Asian countries. We investigated the neuroprotective effects of Polygonum multiflorum against glutamate-induced neurotoxicity with a focus on the anti-apoptotic mechanism in primary cultured cortical neurons.

Material and methods

Cell viability, cytotoxicity, morphological, flow cytometry, Western blot, and caspase activity assays were performed for examination of the neuroprotective effects of active hexane extract from Polygonum multiflorum (HEPM).

Results

Pretreatment with HEPM resulted in significantly decreased glutamate-induced neurotoxicity in a concentration-dependent manner and also resulted in drastically inhibited glutamate-induced apoptosis. Treatment with HEPM resulted in decreased expression of glutamate-induced death receptor (DR)4, and enhanced expression of glutamate-attenuated anti-apoptotic proteins, including Bcl-2, XIAP, and cIAP-1, and slightly reduced glutamate-induced cleavage of Bid. In addition, treatment with HEPM resulted in suppressed glutamate-induced activation of caspase-8, caspase-9, and caspase-3, and, subsequently, decreased degradation of poly(ADP-ribose) polymerase, β-catenin, and phospholipase Cγ1 protein, which are downstream targets of activated caspase-3.

Conclusions

The results of this study demonstrated that HEPM exerts a neuroprotective effect against glutamate-induced neurotoxicity via inhibition of apoptosis. This protection may be mediated through suppression of DR4 and up-regulation of Bcl-2, XIAP, and cIAP-1, as well as inhibition of caspase activation, resulting in prevention of apoptosis of cortical neurons.     

Standardized flavonoid-rich fraction of Artemisia princeps Pampanini cv. Sajabal induces apoptosis via mitochondrial pathway in human cervical cancer HeLa cells

Ethnopharmacological relevance

Artemisia princeps Pampanini is widely used in Eastern traditional medicine for the treatment of circulatory disorders, such as, dysmenorrhea, hematuria, hemorrhoids, and inflammation, and is also used to treat chronic conditions, such as, cancers, ulcers, and digestive disorders.

Aim of the study

The purpose of this study is to investigate the effect of a standardized flavonoid-rich fraction of Artemisia princeps Pampanini cv. Sajabal (FRAP) on the induction of apoptosis and the molecular mechanism involved in human cervical cancer HeLa cells.

Materials and methods

Human cervical cancer HeLa cells were treated with FRAP and apoptosis was detected by cell morphologic observation, annexin-V-PI staning and western blot analysis on the expression of protein associated with cell death.

Results

FRAP led to the cleavages of caspase-3, -8, and -9 and the cleavage of poly (ADP-ribose) polymerase (PARP) in HeLa cells. Caspase-3 inhibitor (z-DEVD-fmk), caspase-8 inhibitor (z-IETD-fmk), caspase-9 inhibitor (z-LEHD), and broad caspase inhibitor (z-VAD-fmk) significantly suppressed the FRAP-induced accumulation of annexin V positive cells. Furthermore, it was found that FRAP caused a loss of mitochondrial membrane potential (MMP) and the release of cytochrome c to the cytosol. Furthermore, the overexpression of Bcl-xL significantly prevented FRAP-induced apoptosis, MMP changes, and the activations of caspase-3, -8, and -9. Interestingly, pretreatment with caspase-8 inhibitor significantly reduced the FRAP-induced activation of caspase-3 but not that of caspase-9, whereas the caspase-3 inhibitor, z-DEVD-fmk, markedly attenuated the FRAP-induced activation of caspase-8. In BALB/c^nu/nu mice bearing a HeLa xenograft, FRAP dosed at 25 or 50 mg/kg significantly inhibited tumor growth.

Conclusion

Our results indicate caspase-mediated activation of the mitochondrial death pathway plays a critical role in the FRAP-induced apoptosis of HeLa cells and that FRAP inhibits the in vivo tumor growth of HeLa xenograft mice.     

乌骨藤中白桦酯酸的提取分离及抗肿瘤活性

目的:对乌骨藤中白桦酯酸进行提取分离,并探讨其抗肿瘤活性.方法:采用硅胶柱色谱法、Sephadex LH-20凝胶柱色谱法及半制备高效液相色谱法,对白桦酯酸进行提取分离,并采用结晶紫法,以细胞死亡率为检测指标,观察白桦酯酸在不同质量浓度1-500mg·L-1情况下,对细胞密度为1×104/孔的4种肿瘤细胞分别作用12,24.36,48 h的生长抑制作用.结果:白桦酯酸对人宫颈癌细胞HeLa、人胃癌细胞MGC、人乳腺癌细胞MCF-7具有很好的增殖抑制作用,并呈剂量依赖效应,在质量浓度为500 mg·L-1作用48h时,对Hela细胞及MGC细胞的死亡率分别为77.9％,81.7％,质量浓度为100 mg·L-1作用48 h时,对MCF-7的细胞死亡率为74.1％,但对人乳腺导管癌细胞(ZR株)作用不显著.结论:白桦酯酸对HeLa,MGC,MCF-7肿瘤细胞具有抗肿瘤活性,对ZR株肿瘤细胞作用不明显.     

仙鹤草多糖的提取及其体外抗脑胶质瘤U251活性研究

目的:优化仙鹤草多糖的提取工艺并测定其对脑胶质瘤U251细胞生长的抑制作用.方法:采用正交设计实验方法对影响仙鹤草多糖得率的提取温度、提取时间、料液比等3因素进行优化;采用MTT比色法测定仙鹤草多糖对U251细胞株增殖的抑制率,应用倒置相差显微镜观察仙鹤草多糖对肿瘤细胞形态结构的影响.结果:仙鹤草多糖提取的最佳工艺条件为:提取温度90℃,提取时间3h,料液比1∶20,在此条件下,仙鹤草总多糖得率可达1.85％.仙鹤草总多糖对脑胶质瘤U251细胞株增殖具有明显的体外抑制作用(P＜0.01),且表现出浓度依赖关系,IC50为1.35 g·L-1.经仙鹤草多糖处理后,U251细胞显示典型的凋亡形态变化.结论:优选的提取工艺简便,高效;仙鹤草总多糖的抗肿瘤效果显著,其抗肿瘤机制可能与诱导肿瘤细胞凋亡有关.     

川芎嗪对白血病U937细胞增殖和凋亡的作用及其机制研究

目的:研究川芎嗪(tetramethylpyrazine,TMP)对白血病U937细胞增殖与凋亡的影响,并初步探讨其作用机制。 方法:应用CCK-8法检测TMP对U937细胞的增殖抑制,流式细胞仪检测细胞凋亡及周期分布,采用Real-time PCR法检测bcl-2,P27 mRNA表达,Western blot检测bcl-2,caspase-3,cyclin E1,CDK2,P27的表达。 结果:川芎嗪呈时间剂量依赖的方式抑制U937细胞的增殖,作用48 h的IC₅₀为160 mg·L^-1;并且诱导U937细胞凋亡,阻滞细胞周期于G₀/G₁期;Real-time PCR及Western blot结果显示川芎嗪使U937细胞中凋亡相关分子bcl-2表达下调,caspase-3上调,周期相关蛋白cyclin E1,CDK2表达下调,P27上调。 结论:川芎嗪对白血病U937细胞呈抑制增殖及诱导凋亡的作用,其机制可能是通过影响细胞周期分布,下调bcl-2的表达,最终激活caspase-3,启动凋亡途径,诱导细胞凋亡。