志苓胶囊通过激活caspase-3抑制K562细胞增殖和诱导细胞凋亡

目的研究志苓胶囊(ZLJN,抗癌复方Ⅱ号)对人慢性髓系白血病K562细胞株增殖及凋亡的影响。方法将志苓胶囊按其不同中西药成分比例配制成中药、西药和复方组,与K562细胞共培养后,采用MTT法、集落形成实验分别检测细胞存活率和集落形成率;Annexin V-FITC/PI标记法、DNA倍体分析及DNA片段化分析检测细胞凋亡;流式细胞仪检测caspase-3活性;Western blot法检测caspase-3酶原(pro-caspase-3)表达。结果不同药物组与K562细胞共培养后,细胞生长受抑制,集落形成率降低。Annexin V-FITC/PI法检测到早期凋亡细胞;DNA倍体分析可见亚二倍体峰(凋亡峰);琼脂糖电泳见典型的DNA梯状带。流式细胞检测caspase-3活性增强,Western blot检测pro-caspase-3表达减弱。结论志苓胶囊可有效抑制K562细胞增殖,诱导其凋亡,其作用机制可能与caspase-3活性增强有关。     

地塞米松衍生物对K562细胞增殖的抑制作用及机制

目的：研究地塞米松衍生物对K562细胞的增殖抑制作用，并对其作用机制进行初步的探讨。方法：以地塞米松为原料合成并纯化得到新的衍生物。用不同浓度的地塞米松衍生物对K562细胞进行处理，通过MTT比色法检测细胞增殖抑制率，电镜法观察细胞凋亡的形态学变化，免疫细胞化学法测定细胞Bcl-2，Fas表达，比色法检测Caspase-3的活性变化。结果：地基米松衍生物能抑制K562细胞的增殖，使Bcl-2表达降低，Fas表达上调，Caspase-3活性增强，诱导K562细胞凋亡。结论：地塞米松衍生物可能通过诱导K562细胞凋亡而抑制细胞增殖。其诱导细胞凋亡的机制可能与抑制Bcl-2蛋白的表达，上调Fas受体，进而激活细胞内的Caspase-3有关。     

维生素E琥珀酸酯诱导耐药白血病K562／ADM细胞凋亡

目的：研究维生素E琥珀酸酯(Vitamin E succinate，VES）对多药耐药白血病K562／ADM细胞的诱导凋亡作用及分子机制。方珐：以体外培养的K562／ADM细胞为研究对象，采用噻唑蓝(Methyl thiazolyl tetrazolium，MTT）比色法检测细胞增殖活性，Wright-Giemsa染色、DNA凝胶电泳和流式细胞术(Flow cytometry，FCM）检测细胞凋亡；FCM测定细胞Fas，Bcl-2、P53蛋白表达水平。结果：VES可显著抑制K562／ADM细胞的生长及增殖；光镜下可见K562／ADM细胞呈典型凋亡的形态学改变；DNA凝胶电沫显示典型的凋亡DNA梯形条带，FCM细胞周期分析显示G1期阻滞，亚G1期细胞比例增高；Fas蛋白表达明显上调，Bcl-2蛋白表达下调，p53蛋白表达无明显变化。结论：VES可诱导K562／ADM细胞凋亡，作用机制可能与其上调Fas表达和下调Bcl-2表达有关。     

锰超氧化物岐化酶模拟化合物诱导K562细胞凋亡的机制研究

目的观察锰超氧化物岐化酶模拟化合物(mimics of manganese superoxide dismutase,MnSODm)对人白血病K562细胞凋亡诱导作用,并探讨其分子机制。方法以人白血病K562细胞为靶细胞,四氮唑蓝比色法(MTT法)测定细胞增殖活性;Annexin V/PI双标记和细胞形态学法检测细胞凋亡;RT-PCR检测bcl-2和bax基因mRNA的表达水平;流式细胞术(FCM)测定Bcl-2和Bax蛋白表达水平、线粒体跨膜电位(Δψm)、细胞色素C(Cyt C)释放和Caspase-3活性变化。结果0.5~10mg·mL-1MnSODm明显抑制K562细胞增殖(P<0.01),Annexin V/PI染色显示凋亡细胞明显增多,光学显微镜和透射电镜观察呈现典型的凋亡形态改变;bcl-2基因mRNA和蛋白表达下调,bax基因mRNA和蛋白表达上调,线粒体Δψm降低,Cyt C释放增多,Caspase-3活性增强。结论MnSODm调控Bax/Bcl-2表达,通过线粒体途径诱导K562细胞凋亡。     

二甲氧雌二醇对白血病细胞K562增殖、凋亡的作用及其机制

目的：研究二甲氧雌二醇（2-ME）对人白血病细胞l（562细胞的增殖、凋亡的作用及其机制。方法：分别以不同浓度的2-ME处理白血病细胞K562,通过MTT法检测K562细胞活力,应用AnnexinV和PI双染的流式细胞术检测K562细胞凋亡率,应用凝胶蛋白电泳迁移率分析法EMSA检测K562细胞核内NF．KB蛋白的结合活性变化情况。结果：随着2-ME浓度的升高,各项指标与对照组相比较的差异均有统计学意义（P〈0．01）;K562细胞增殖明显受到抑制;细胞凋亡率明显增加,且当2·ME浓度为8μmol·L-1时,细胞凋亡率达64．3％;同时K562细胞核内NF—kappaB的DNA结合活性明显降低。结论：2-ME可显著抑制人白血病细胞K562增殖并诱导其凋亡;2-ME诱导K562细胞凋亡的机制与NF—kappaB蛋白信号通路有关。     

分枝石蕊多糖诱导人白血病K562细胞凋亡

目的：研究分枝石蕊多糖（CFP-1）是否能诱导K562细胞凋亡。方法：抑制细胞增殖的测定采用MTT法;用荧光显微镜和透射电镜观察细胞的形态学变化;采用琼脂糖凝胶电泳法观测DNA碎片;用流式细胞仪检测凋亡细胞数。结果：CFP-1（50-800mg/L）明显抑制K562细胞增殖,并且呈浓度依赖性,K562细胞与CFP-1300mg/L共同培养5d后,观察到典型的凋亡形态变化,电泳呈现梯形条带。结论：CFP-1诱导人白血病K562细胞凋亡。     

辣椒素经内质网应激反应途径诱导K562/ADM耐药细胞凋亡

目的：研究辣椒素（capsaicin）是否经内质网途径诱导耐药性白血病K562/ADM细胞凋亡。方法：以耐药性白血病K562/ADM细胞为靶细胞,采用MTT比色法测定细胞增殖活性;细胞形态学和AnnexinV/PI双染色法检测细胞凋亡,电镜观察凋亡细胞内质网形态结构变化;实时定量RT-PCR检测GRP78mRNA的表达;Western blot法检测GRP78蛋白的表达。结果：不同浓度的辣椒素显著抑制K562/ADM细胞的增殖活性,20、50μmol/L辣椒素诱导后K562/ADM细胞出现典型的凋亡形态学改变,细胞凋亡率明显增高,分别为39.67%和41.78%。辣椒素诱导凋亡过程中,K562/ADM细胞出现内质网明显扩张和脱颗粒现象,GRP78mRNA的表达增高,GRP78蛋白的表达量分别增高1.5和2.2倍,随时间延长有所降低。结论：辣椒素可能通过内质网应激反应性途径诱导K562/ADM细胞发生凋亡。     

锰超氧化物歧化酶模拟化合物通过Fas途径诱导白血病K562细胞凋亡

目的：探讨锰超氧化物歧化酶模拟化合物（mi mics of manganese superoxide dismutase,MnSODm）对人白血病K562细胞的凋亡诱导效应及作用机制。方法：应用MTT比色法、An-nexin V/PI双标记和细胞形态学法观察细胞凋亡;流式细胞术（FCM）测定Fas蛋白表达水平;RT-PCR检测Caspase-3mRNA的表达水平,比色法测定Caspase-3活性变化。结果：MnSODm作用后K562细胞的增殖受到抑制,Annexin V/PI染色显示凋亡细胞明显增多,透射电镜观察呈现典型的凋亡形态改变。同时,Fas蛋白表达水平显著增高,Caspase-3mRNA表达水平明显升高,活性显著增强。结论：MnSODm可能通过Fas途径诱导白血病K562细胞凋亡。     

硝普钠抑制K562细胞增殖并诱导细胞凋亡的实验研究

目的：观察外源性一氧化氮(NO)供体硝普钠对K562细胞增殖抑制及诱导细胞凋亡作用：方法：将不同浓度的硝普钠与K562细胞在体外培养，观察其作用时间效应和剂量效应；用活细胞计数、MTT法观察硝普钠对K562细胞增殖的抑制作用；用DNA凝胶电泳、DNA含量及细胞周期分析、Annexin—V／PI双标记和DNA片段原位末端标记法等分析细胞凋亡。同时设高铁氰化钾(PFC)对照组和空白对照组。结果：NO能抑制K562细胞生长，并在一定的剂量范围内呈现作用时间和剂量的量效关系．大部分细胞阻滞于G0／G1期；K562细胞与硝普钠作用后出现典型的细胞形态改变，DNA片断化，亚G1峰检出并显著增加，Annexin V／PI和DNA片段原位末端标记表达增加等均证实NO能诱导K562细胞凋亡。而对照组并无此类变化。结论：NO通过阻滞G0／G1期细胞显著抑制K562细胞的增殖，并有很强的致凋亡作用。     

一种海洋来源的ETP类化合物HDN-1诱导K562细胞凋亡作用及机制初探

目的 探讨南极土壤来源真菌的次级代谢产物HDN-1对人慢性粒细胞白血病K562细胞的增殖抑制,诱导凋亡作用及其机制。方法 采用MTT法检测HDN-1对K562细胞的增殖抑制作用;DNA结合染料Hoechst 33342染色,Western Blotting以及DNA琼脂糖凝胶电泳检测细胞凋亡以及凋亡相关蛋白的变化。结果 HDN-1能显著抑制K562细胞的增殖,并呈剂量-时间依赖性;HDN-1作用后,细胞核形态发生明显变化并且出现了基因组DNA的梯状剪切条带;Caspase-9、8、3逐渐被激活,Caspase3的作用底物PARP被活化裂解出现89KD的剪切条带,并且Caspase蛋白的激活可被特异性抑制剂所阻断;抑凋亡蛋白Bcl-2,Mcl-1的表达降低,促凋亡蛋白Bax的表达量增高。另外,融合蛋白Bcr-Abl的表达被HDN-1抑制并呈剂量依赖性。结论 来源于南极土壤来源真菌的次级代谢产物HDN-1可能是通过抑制Bcr-Abl融合蛋白的表达进而诱导K562细胞凋亡,并且凋亡是通过Caspase依赖的线粒体途径和死亡受体途径共同介导发生的。     

Diosgenin-3-O-alpha-L-rhamnopyranosyl-(1 --> 4)-beta-D-glucopyranoside obtained as a new anticancer agent from Dioscorea futschauensis induces apoptosis on human colon carcinoma HCT-15 cells via mitochondria-controlled apoptotic pathway

Diosgenin-3-O-alpha-L-rhamnopyranosyl-(1 --> 4)-beta-D-glucopyranoside (DRG) is a well-known pentacyclic triterpene glycoside newly isolated from the rhizomes of Dioscorea futschauensis R. Kunth (Dioscoreaceae) by our group. In the present work, the inhibitory effect of DRG on the cell proliferation of human cancer cell lines was examined to reveal for the first time that DRG shows stronger anticancer activity than that of the positive control cisplatin. DRG inhibited the proliferation of human cancer cells, A431, A2780, A549, K562, and HCT-15, with IC50 (micromol L(-1)) values of 9.33 +/- 0.22, 18.7 +/- 0.16, 9.98 +/- 0.38, 6.44 +/- 0.10, and 5.86 +/- 0.14 respectively. It was then found, by morphological observation, "DNA ladder" detection and flow cytometric analysis, that DRG exerts its anticancer effect through inducing apoptosis on HCT-15 cells. Furthermore, it has been demonstrated that DRG triggers a mitochondria-controlled apoptotic pathway to induce apoptosis on HCT-15 cells, which involves the reduction of the mitochondrial potential (deltapsim), the release of cytochrome c from mitochondria into the cytosol, and the down-regulation of the ratio of Bcl-2/Bax expression level. The present results reasonably suggest that regulating the balance of Bcl-2/Bax expression level plays a key role in the DRG-induced apoptosis. Such findings provide novel knowledge to elucidate the biological properties of DRG, even though DRG was discovered early in the late 1960s. These results suggest that DRG may be a good candidate as a chemotherapeutic agent to treat human colon carcinoma.     

Possible participation of chloride ion channels in ATP release from cancer cells in suspension

1. Cancer cells must detach from the primary focus to initiate the process of metastasis. Previously, we demonstrated that intracellular Ca(2+) levels are increased in endothelial cells in the presence of cancer cells and that ATP derived from these cells causes this increase. The present study clarifies the mechanism of ATP release from cancer cells by investigating the effects of Cl(-) channel inhibitors and other drugs on ATP release from human fibrosarcoma cells (HT-1080 cells). 2. Levels of extracellular ATP and its metabolites were measured using high-performance liquid chromatography (HPLC) with fluorescent detection. 3. Significantly more extracellular ATP was released by suspended than by adherent HT-1080 cells. The Cl(-) channel inhibitors 5-nitro-2-(3-phenylpropylamino) benzoic acid (100 micromol/L), gadolinium (100 micromol/L) and niflumic acid (100 micromol/L) all significantly inhibited ATP release from HT-1080 cells (1 x 10(3) /mL) to 39.7 +/- 6.5, 28.5 +/- 2.5 and 82.5 +/- 4.1% of control, respectively. 4. Neither of the p-glycoprotein inhibitors (i.e. 50 micromol/L quinidine and 90 micromol/L verapamil) had any effect on ATP release from HT-1080 cells. The gap junction hemichannel inhibitor Gap26 (300 micromol/L) slightly, but significantly, decreased ATP release by approximately 20%. The gap junction inhibitor 18-alpha-glycyrrhetinic acid (10 micromol/L) tended to inhibit ATP release from HT-1080 cells, but the difference did not reach statistical significance. 5. These findings indicate that Cl(-) channels play the most important role in ATP release from detached cancer cells and that gap junction hemichannels are also associated with ATP release.     

As2S2诱导K562细胞凋亡及其机制

目的:探索As_2S_2对K562细胞的作用及其机制.方法:As_2S_2对K562细胞的生长抑制作用用细胞计数法;细胞凋亡的检测用流式细胞分析、基因组DNA电泳、细胞形态学观察等方法;Western-blot方法用于蛋白表达的检测;基因表达的变化用半定量RT-PCR方法.结果:As_2S_2浓度在1-5μmol/L作用24-72 h即可抑制K562细胞生长,大于3μmol/L时可诱导K562细胞凋亡.As_2S_2能降低K562细胞中Bcr-Abl蛋白水平及 c-abl和 Bcr-Abl PTK活性,但不调变bcr-abl基因表达水平.As_2S_2也能诱导慢性粒细胞性白血病(CML)患者单个核细胞凋亡,且Ph~ 单个核细胞比Ph~- 单个核细胞对As_2S_2诱导的凋亡更敏感.结论:As_2S_2可通过降低Bcr-Abl蛋白含量而诱导CML细胞凋亡.As_2S_2可能为治疗CML的有效药物.     

二氢青蒿素抑制K562细胞血管内皮生长因子的表达

目的通过观察二氢青蒿素抑制K562细胞血管内皮生长因子(VEGF)的表达，探讨青蒿素类药物在抑制血液肿瘤血管新生方面的作用。方法运用MTT法、免疫组化分析和Western blotting分析等探讨了二氢青蒿素对K562细胞增殖以及VEGF表达方面的影响，并进一步对药物预处理后肿瘤细胞的条件培养基在促内皮细胞增殖以及促鸡胚绒毛尿囊膜(CAM)血管新生的作用进行评定。结果二氢青蒿素能有效抑制K562细胞的增殖，并显著下调K562细胞VEGF蛋白和mRNA的表达。同时,药物预处理细胞的条件培养基，其促内皮细胞增殖和促CAM血管新生的能力都有所下降，并呈药物浓度依赖性。结论二氢青蒿素能显著下调K562细胞VEGF的表达，并能抑制由其诱导的血管新生作用。     

丹皮酚诱导K_(562)细胞凋亡的研究

目的　探讨丹皮酚 (Paeonol,Pae)对K562 细胞增殖和凋亡的影响。方法　采用MTT法检测丹皮酚对体外培养的K562 细胞的增殖抑制作用 ,通过HE染色和流式细胞仪定性和定量分析Pae的诱导凋亡作用。结果　Pae在 7 81～2 5 0mg·L-1浓度范围内对K562 细胞的增殖均有抑制作用 ,呈现明显的剂量依赖效应关系。HE染色光镜下可见典型的肿瘤细胞凋亡改变。Pae在 7 81、15 6 3、31 2 5、6 2 5及12 5mg·L-1浓度下作用 2 4h均可诱导K562 细胞凋亡 ,其凋亡率分别为 10 0 1%、 12 4 6 %、 17 10 %、 2 9 18%和34 16 % ,有明显的剂量效应关系 ,Pae 6 2 5、2 5、10 0mg·L-13种浓度分别作用于K562 细胞 6、12及 2 4h。发现以上各种浓度在 6h即可诱导细胞凋亡 ,作用时间越长 ,凋亡率越高 ,有明显的时间效应关系。结论　Pae能抑制K562 细胞增殖和诱导凋亡     

洛美利嗪逆转K562/ADM细胞多药耐药性

目的研究洛美利嗪(lomerizine,Lom)逆转K562/ADM细胞多药耐药性的作用及机制。方法MTT法检测细胞毒作用,流式细胞仪研究Lom对ADM和长春新碱(vincristine,VCR)的K562/ADM细胞凋亡诱导作用的影响及对罗丹明123(rhodamine 123,Rh123)外排和P-糖蛋白(P-glycoprotein,P-gp)表达的作用。结果Lom明显提高ADM对K562/ADM多药耐药细胞的细胞毒作用及ADM和VCR的凋亡诱导作用,3,10和30 μmol·L^-1 Lom使K562/ADM对ADM的IC₅₀值由79.03 μmol·L^-1分别降至28.14,8.16和3.16 μmol·L^-1。Lom增加胞内ADM的蓄积浓度并抑制Rh123外排;但作用72 h后对K562/ADM细胞P-gp表达无影响。结论Lom通过抑制P-gp的活性逆转K562/ADM细胞的多药耐药性。     

冬凌草甲素对K562细胞端粒酶活性调控及细胞周期的影响

目的研究冬凌草甲素(ORI)对K562细胞端粒酶活性及其细胞周期的影响。方法免疫细胞化学法测定K562细胞中hTERT和C-myc蛋白的表达；TRAP-PCR-ELISA法检测了端粒酶活性变化；流式细胞仪测定细胞周期各时相百分比。结果用3.43 μmol·L^-1 ORI作用于Ｋ562细胞48 h后，hTERT和C-myc蛋白的表达降低；在一定的浓度范围内，ORI可下调K562细胞端粒酶活性。同时细胞周期各时相分布发生变化，G₀/G₁期或G₂/M期细胞增多，S期细胞减少。结论ORI可下调K562细胞的端粒酶活性，其机制可能与其细胞周期阻滞作用及抑制hTERT和C-myc蛋白的表达有关。     

Molecular mechanisms in C-Phycocyanin induced apoptosis in human chronic myeloid leukemia cell line-K562

C-Phycocyanin (C-PC), the major light harvesting biliprotein from Spirulina platensis is of greater importance because of its various biological and pharmacological properties. It is a water soluble, non-toxic fluorescent protein pigment with potent anti-oxidant, anti-inflammatory and anti-cancer properties. In the present study the effect of highly purified C-PC was tested on growth and multiplication of human chronic myeloid leukemia cell line (K562). The results indicate significant decrease (49%) in the proliferation of K562 cells treated with 50 microM C-PC up to 48 h. Further studies involving fluorescence and electron microscope revealed characteristic apoptotic features like cell shrinkage, membrane blebbing and nuclear condensation. Agarose electrophoresis of genomic DNA of cells treated with C-PC showed fragmentation pattern typical for apoptotic cells. Flow cytometric analysis of cells treated with 25 and 50 microM C-PC for 48 h showed 14.11 and 20.93% cells in sub-G0/G1 phase, respectively. C-PC treatment of K562 cells also resulted in release of cytochrome c into the cytosol and poly(ADP) ribose polymerase (PARP) cleavage. These studies also showed down regulation of anti-apoptotic Bcl-2 but without any changes in pro-apoptotic Bax and thereby tilting the Bcl-2/Bax ratio towards apoptosis. These effects of C-PC appear to be mediated through entry of C-PC into the cytosol by an unknown mechanism. The present study thus demonstrates that C-PC induces apoptosis in K562 cells by cytochrome c release from mitochondria into the cytosol, PARP cleavage and down regulation of Bcl-2.     

Astilbic acid induced COLO 205 cell apoptosis by regulating Bcl-2 and Bax expression and activating caspase-3

AIM: To investigate the effect of astilbic acid (3β, 6β-dihydroxyolean-12-en-27-oic acid, AA) on human colorectal carcinoma COLO 205 cell proliferation and apoptosis. METHODS: Proliferation of COLO 205 cells was measued by MTT assay. Content of DNA in COLO 205 cell was measued by modified diphenylamine assay. AA-induced morphological changes was observed with fluorescence microscope and transmission electron microscope. DNA fragmentation was visualized by agarose gel electrophoresis. Apoptosis rate and cell cycle distribution were determined by flow cytometric analysis. Expressions of Bcl-2 and Bax proteins were visioned by immunohistochemical analysis. The change of relative mitochondral transmembrane potential (MTP) in COLO 205 cell was analyzed with FCM after rhodamine 123 staining. RESULTS: The IC50 (96 h) of AA for inhibiting COLO 205 cell proliferation was 61.56 0.34 μmol/L. AA induced a marked concentration- and time-dependent inhibition of COLO 205 cell proliferation and reduced the DNA content in COLO 205 cell. Cells treated with AA 64 μmol/L showed typical morphological changes of apoptosis and DNA “ladder“ pattern. The cell cycle was arrested in G0/G1 phase, and the apoptosis rate was 28.25 % for COLO 205 cells treated with AA 64 μmol/L for 48 h. Meanwhile the expression of Bcl-2 protein was decreased while that of Bax was increased and relative MTP was decreased as well. DEVD-CHO1 μmol/L could increase the viability of COLO 205 cells treated with AA for 48 h. CONCLUSION: AA showed potent inhibitory activity on COLO 205 cells proliferation, and could induce COLO 205 cells apoptosis through disturbing DNA replication, down-regulating Bcl-2 expression, and up-regulating Bax expression, lowering relative MTP, and activating caspase-3 pathway.     

二氢青蒿素下调粒系白血病细胞转铁蛋白受体表达

通过建立常铁HL60和K562细胞以及富铁K562细胞体外模型，研究二氢青蒿素对粒系白血病细胞转铁蛋白受体(transferrin receptor，TfR)的调控作用。采用流式细胞术检测二氢青蒿素对粒系白血病细胞TfR密度的调控作用，Western blotting和RT-PCR法检测二氢青蒿素对粒系白血病细胞TfR表达的调控作用，原子吸收分光光度法检测二氢青蒿素对常铁和富铁K562细胞铁含量的影响，以及MTT法和台盼蓝拒染法分析二氢青蒿素对粒系白血病细胞增殖的作用。结果显示，二氢青蒿素能显著降低常铁HL60和K562细胞TfR的密度和下调TfR蛋白的表达，且呈浓度和时间依赖性，并能有效地抑制细胞增殖，IC₅₀值分别为1.74和11.33 μmol·L^-1。二氢青蒿素对富铁K562细胞的TfR蛋白和mRNA表达能进一步增强下调作用，与常铁培养组比较，10 μmol·L^-1二氢青蒿素对富铁K562细胞TfR蛋白和TfR mRNA表达量分别下调了28.1%(P<0.01)和26.2%(P<0.05)，并能显著下降富铁K562细胞铁的含量(P<0.05)，更有效地抑制富铁K562细胞增殖。由此可见，二氢青蒿素能下调粒系白血病细胞TfR密度以及TfR蛋白和mRNA的表达，有效抑制常铁HL60和K562细胞的增殖，对富铁K562细胞增殖的抑制作用能进一步增强。