线粒体途径在肿瘤坏死因子凋亡诱导配体诱导结肠癌细胞凋亡中的调节作用

目的探讨线粒体途径在肿瘤坏死因子凋亡诱导配体(TRAIL)诱导结肠癌细胞凋亡过程中的调节作用,为临床合理用药提供理论指导。方法采用流式细胞仪技术、荧光显色技术和Western印迹技术检测TRAIL处理结肠癌细胞SW1116后,在不同时间细胞凋亡情况、线粒体完整性改变(ΔΨm、cardiolipin情况)以及线粒体下游通路细胞色素C和Caspase-9的表达情况。结果TRAIL诱发结肠癌细胞凋亡,于4 h达凋亡高峰,凋亡指数为32．98%；在4 h出现线粒体ΔΨm下降和cardiolipin丢失增加,造成其内膜损伤；细胞色素C表达及Caspase-9酶活性随时间的延长而增加,24 h酶活性达到最大峰值为(48．12±2．21)μmol·L~(-1)·h~(-1)·mg~(-1)蛋白。TRAIL诱导的线粒体损伤可被Caspase抑制剂Z-VAD．fmk所抑制。结论线粒体途径参与TRAIL诱导结肠癌细胞的凋亡过程,以Caspase依赖方式引发线粒体ΔΨm和cardiolipin丢失,造成内膜损伤,导致细胞色素C释放和Caspase-9激活,诱发凋亡。     

染料木黄酮诱导前列腺癌DU-145细胞凋亡的研究

【摘要】〓目的〓探讨染料木黄酮诱导前列腺癌细胞系DU-145细胞凋亡的作用。方法〓在Caspase抑制剂Z-VAD存在或不存在的情况下,以染料木黄酮作用于前列腺癌DU-145细胞,采用MTT法检测细胞存活率、Annexin V-FITC/PI双染法流式细胞术检测细胞凋亡、PI染色法流式细胞术检测细胞周期、JC-1染色法流式细胞术测定细胞线粒体膜电位(△ψm),比色检测试剂盒测定caspase-8活性。结果〓染料木黄酮能明显降低前列腺癌DU-145细胞的存活率、诱导癌细胞凋亡、降低△ψm及提高caspase-8活性(全部P<0.05)。Z-VAD能够逆转Gen抗前列腺癌的效应。结论〓染料木黄酮使细胞阻滞于G0和G1,分别通过凋亡信号通路的外源性和内源性途径,诱导前列腺癌细胞凋亡。     

肿瘤坏死因子凋亡诱导配体诱导膀胱癌EJ细胞凋亡的研究

目的 探讨肿瘤坏死因子凋亡诱导配体(TRAIL)诱导膀胱癌细胞凋亡的效应。方法 10～100μg／L梯度浓度的TRAIL与培养的EJ细胞共孵育4～24h。采用Annexin V染色，DNA云梯实验和流式细胞技术检测诱导后EJ细胞凋亡发生的时期和程度。结果 TRAIL诱导4h即后可观察到早期细胞凋亡发生，8h后即可检测DNA片段化，24h后凋亡细胞最多达到66．29％。结论 TRAIL能够迅速诱导EJ细胞凋亡，可能成为膀胱癌治疗的新方法。     

白藜芦醇促进膀胱癌细胞对TRAIL凋亡诱导作用的研究

目的探讨白藜芦醇对膀胱癌细胞的作用及其与TRAIL联合对膀胱癌细胞的凋亡诱导作用及其可能的机制。方法MTT法检测白藜芦醇或/和TRAIL对膀胱癌细胞5637和T24体外生长能力的影响。流式细胞术测定白藜芦醇和/或TRAIL对细胞凋亡和线粒体跨膜电位的影响。Western blot检测白藜芦醇对死亡受体(DR)4、5与细胞凋亡相关蛋白表达水平的变化。结果 MTT证实白藜芦醇可抑制膀胱癌细胞体外生长能力,且呈剂量与时间依赖性。单独应用TRAIL未能抑制膀胱癌细胞的生长,但与白藜芦醇联合应用时可显著抑制细胞的增殖速度。白藜芦醇能够诱导膀胱癌细胞发生凋亡,而TRAIL则不能诱导细胞凋亡,但联合应用白藜芦醇和TRAIL可诱导膀胱癌细胞发生显著的凋亡。此外,在白藜芦醇或联合应用白藜芦醇与TRAIL可诱导肿瘤细胞丢失线粒体膜电位(ΔΨm),而单独应用TRAIL则未能诱导线粒体膜电位的丢失。Western blot结果表明,白藜芦醇可上调DR4和DR5的表达,并下调Bcl-2与survivin的表达。结论白藜芦醇可抑制膀胱癌5637和T24细胞增殖并诱导细胞凋亡。此外,白藜芦醇可以提高膀胱癌细胞对TRAIL诱导的细胞凋亡作用。单独应用白藜芦醇或与TRAIL联合应用可能成为临床膀胱癌治疗的新策略。     

西罗莫司诱导人肝癌细胞株BEL-7402凋亡及其机制

目的探讨西罗莫司（SRL）在体外诱导人肝癌细胞株BEL-7402的凋亡作用及其机制。方法以不同浓度的SRL（5、10、20、30、40和50nmol／L）作用于体外培养的人肝癌细胞株BEL-7402，应用流式细胞仪检测培养24、48和72h时的细胞凋亡情况；Hoechst 33258荧光染色法观察细胞凋亡时的形态学变化；Western Blot法观察BEL-7402细胞中Caspase-3、Bcl-2、Bcl-xl和Bax基因的表达变化；采用Caspase-3试剂盒检测Caspase-3酶的活性；JCl染色法检测细胞线粒体膜电位（△ψbm）。结果SRL可诱导BEL-7402细胞凋亡，并与药物浓度和作用时间呈正相关。SRL作用BEL-7402细胞后48h，在Hoechst33258荧光染色图片上可见核浓缩及核碎裂等典型的细胞凋亡特征，凋亡过程中线粒体膜电位下降及Caspase-3酶原蛋白激活，伴有Bcl-2、Bcl-xl蛋白表达的降低和Bax蛋白上调。结论SRL能使抗凋亡蛋白Bcl-2、gcl-xl表达降低，促凋亡蛋白Bax表达上调，线粒体膜电位下降，激活Caspase-3酶原蛋白，从而诱导细胞凋亡。     

肿瘤坏死因子相关凋亡诱导配体诱导前列腺癌细胞凋亡的研究

目的 研究肿瘤坏死因子相关凋亡诱导配体(TRAIL)对前列腺癌细胞的凋亡诱导作用。方法 10μg/L-100μg/L的TRAIL处理培养的PC-3M细胞4～24h后，采用Annexin-V荧光染色、透射电镜、原位末端转移酶标记技术(TUNEL)检测肿瘤细胞凋亡；流式细胞术和MTT比色检测凋亡率、细胞生长抑制率与TRAIL的时间、浓度依赖关系。结果10μg/L～100μg/L TRAIL作用4～24h，肿瘤细胞出现典型的凋亡形态学改变，随着TRAIL浓度的增加或药物作用时间的延长，肿瘤细胞凋亡率也增加，为13．8％～79．6％，同时细胞生长抑制率出现明显增加，药物作用8h为7．5％～37．9％，12h为16．7％～87．9％，24h为39．7％～97．6％。结论 TRAIL能够迅速和显著地诱导PC-3M细胞凋亡，可能成为晚期前列腺癌治疗的新方法。     

肿瘤坏死因子相关凋亡诱导配体诱导结肠癌HCT-116细胞凋亡和炎性反应相关基因表达的研究

目的探讨肿瘤坏死因子相关凋亡诱导配体（TRAIL）对结肠癌细胞凋亡和炎性反应相关基因表达的影响。方法HCT-116细胞经10μg／L和100μg／L重组人类TRAIL蛋白处理后,应用荧光实时定量PCR和试剂盒测定凋亡相关基因（Bcl-2、Bad、caspase-3和-8）和炎性反应相关基因（TNF—α,IL-1β,COX-2）的表达水平。结果经10μg几和100μg／L重组人类TRAIL蛋白孵育处理24h后．HCT-116细胞的凋亡率分别为27．4％和45．9％。同时抗凋亡基因Bcl-2、促凋亡基因Bad以及凋亡指示基因caspase-3和caspase-8的表达均显著上调。且100μg／L组的上调幅度均高于10μg／L组（P〈0．05）。TRAIL蛋白处理后,炎性反应相关基因TNF-α,IL-1β,COX-2的表达亦显著上升．且100μg／L处理组的上升幅度均高于10μg／L组（P〈0．05）。结论TRAIL重组蛋白能够诱导结肠癌细胞凋亡以及炎性反应的发生。     

南瓜蛋白诱导人胰腺癌细胞凋亡的线粒体机制

目的 探讨南瓜蛋白(CUS)诱导人胰腺癌细胞(PANC)-1凋亡的线粒体机制.方法 0、2.5、10.0、40.0 mg/L的CUS处理胰腺癌PANC-1 72 h,荧光显微镜和流式细胞仪观察线粒体膜电位(△Ψm)的变化,Western blot检测胞质细胞色素C(Cyt-C)的含量变化和细胞半胱氨酰天冬氨酸特异性蛋白酶-9(Caspase-9)和Caspase-3、B细胞淋巴瘤/白血病-2(bcl-2)和B细胞淋巴瘤/白血病-2相关X蛋白(bax)蛋白的表达水平.结果 0、2.5、10.0、40.0 mg/L CUS处理PANC-1 72 h后,△Ψm逐渐下降,分别为167.23±8.27、123.56±7.26、83.25±5.36和40.45±5.87,差异有统计学意义(P＜0.05);Western blot结果显示线粒体Cyt-C释放到细胞质的量逐渐增加,灰度值分别为0.29±0.05、1.69±0.35、1.87±0.40、2.47±0.32(P＜0.05);Caspase-9、Caspase-3和bax蛋白的表达逐渐增强,且其作用呈剂量依赖性(Caspase-9灰度值分别为0.15±0.03、0.19±0.05、0.49±0.09、0.89±0.08,P＜0.05;Caspase-3灰度值分别为0.88±0.08、1.81±0.19、2.36±0.38、2.92±0.24,P ＜0.05;bax灰度值分别为0.79±0.18、1.66±0.31、2.61±0.41、3.67±0.24,P＜0.05);而bcl-2蛋白表达无明显变化(bcl-2灰度值分别为0.88±0.08、0.82±0.18、0.84±0.04、0.82±0.13,P＞0.05).结论 线粒体途径在CUS诱导胰腺癌细胞凋亡中起重要作用,其机制可能是CUS通过激活促凋亡蛋白bax表达增加,降低△Ψm,促进线粒体Cyt-C的释放,从而激活Caspase系列酶,诱导胰腺癌细胞凋亡.     

靶向抑制XIAP基因后结肠癌细胞对凋亡诱导配体耐药性的变化

目的 观察应用短发夹RNA(shRNA)干扰质粒靶向抑制X连锁凋亡抑制蛋白(XIAP)基因后,结肠癌细胞SW1116对肿瘤坏死因子相关的凋亡诱导配体(TRAIL)耐药性的变化.方法 采用脂质体包裹方法,将干扰质粒转染结肠癌细胞SW1116,48 h后检测转染前后XIAP蛋白表达和结肠癌细胞生长活性的变化;应用TRAIL药物25、50、100、200 μg/L梯度浓度作用于结肠癌细胞,24 h后噻唑蓝(MTT)比色法检测抑制XIAP表达后结肠癌细胞对TRAIL敏感性的变化,并利用蛋白印迹方法检测细胞内凋亡相关因子Caspase-3活性的改变.结果 转染干扰质粒后XIAP的表达能够得到有效抑制(抑制率60%),细胞的生长活性得到抑制(抑制率24%),结肠癌细胞对TRAIL的耐药得到逆转,对TRAIL的敏感性显著提高,在200μg/L浓度下细胞生长抑制率可达64%,肿瘤细胞内的Caspase-3的表达活性得到提高.结论 靶向抑制XIAP基因的表达能够恢复和增强结肠癌细胞对TRAIL的敏感性.     

肿瘤相关凋亡诱导配体、Survivin、Caspase-3和NF-κB在大肠癌中的表达

肿瘤相关凋亡诱导配体（TRAIL）与FasL有较高的同源性，其选择性地诱导肿瘤细胞发生凋亡，从而使正常细胞逃逸其杀伤作用。有研究结果表明，许多肿瘤对TRAIL并不敏感．Sunivin、NF-κB和Caspase．3是TRAIL诱导细胞凋亡通路中三个关键性的影响因子。我们通过其在大肠癌中的表达的研究以期阐明TRAIL的效能与Survivin、Caspase．3和NF-κB表达的关系。     

Osteocyte apoptosis

Apoptotic death of osteocytes was recognized over 15 years ago, but its significance for bone homeostasis has remained elusive. A new paradigm has emerged that invokes osteocyte apoptosis as a critical event in the recruitment of osteoclasts to a specific site in response to skeletal unloading, fatigue damage, estrogen deficiency and perhaps in other states where bone must be removed. This is accomplished by yet to be defined signals emanating from dying osteocytes, which stimulate neighboring viable osteocytes to produce osteoclastogenic cytokines. The osteocyte apoptosis caused by chronic glucocorticoid administration does not increase osteoclasts; however, it does negatively impact maintenance of bone hydration, vascularity, and strength.This article is part of a Special Issue entitled "The Osteocyte".     

Malnutrition-induced macrophage apoptosis

BACKGROUND: Human and murine studies suggest protein-calorie malnutrition (PCM) results in significant host immunosuppression resulting in increased morbidity and mortality. Apoptosis has been implicated as an important mediator in the immunosuppression observed in several disease states. This study was designed to characterize macrophage apoptosis in a murine model of PCM and investigate components that regulate the apoptotic process, such as protein kinase C (PKC) and Bcl-2 activity. METHODS: Swiss-Webster mice (n = 50) were randomly assigned to receive either a control (24% protein) or a PCM diet (0% protein) for 7 days. Peritoneal macrophages were harvested and detection of apoptosis was performed by terminal deoxy-transferase-mediated deoxyuridine triphosphate (dUTP) nick-end labeling (TUNEL) and propidium iodide DNA staining under baseline and pro-apoptotic conditions. Pro-apoptotic conditions included cells treated with tumor necrosis factor-alpha (TNF-alpha) (10 ng/mL), interferon-gamma (IFN-gamma) (10 ng/mL), and a combination of both agents. In addition, levels of PKC activity and expression of Bcl-2 and p53 protein were measured. RESULTS: Peritoneal macrophages from PCM mice had a significantly greater amount of apoptosis at baseline and under stimulated conditions compared with controls. Levels of PCM apoptosis were elevated at baseline by TUNEL staining compared with macrophages from the control group (16.5% +/- 1.4%, versus 4.5% +/- 1.1%, P <.01). In addition, peritoneal macrophages from the malnourished animals were significantly more susceptible to the apoptotic effect of TNF-alpha and the effects of INF-gamma (27.3% +/- 2.1% and 31% +/- 1.4%) compared with control mice (5.5% +/- 0.7% and 7.2% +/- 0.5%, P <.01), respectively. Again, an increase in the baseline apoptosis rate was demonstrated in peritoneal macrophages from PCM mice compared with control fed mice (13.2% +/- 4.4% versus 4.3% +/- 3.1%, P <.01) as measured by propidium iodide staining. The combination of agents, TNF-alpha and INF-gamma, resulted in an additive apoptotic effect in the malnourished host compared with the control animals (43.4% +/- 4.7% versus 10.5% +/- 2.2%, P <.01), respectively. Furthermore, there was a significant decrease in the mean total PKC activity in the malnourished macrophages compared with results in controls (110,000 +/- 8000 versus 60,000 +/- 4000 cpm, P <.01). Similar changes were also observed in PKC cytosolic and membrane activity between both groups. In addition, Bcl-2 protein expression was significantly decreased in PCM animals compared with control animals. CONCLUSIONS: Thus, peritoneal macrophages from PCM mice exhibit significantly greater levels of apoptosis at baseline and when stimulated with pro-apoptotic agents compared with controls. The propensity of macrophages from PCM mice to undergo apoptosis may be attributable in part to decreased PKC activity and Bcl-2 protein expression. These findings may help to explain the associated immune dysfunction observed in malnutrition.     

Expression of apoptosis regulatory genes in chronic cyclosporine nephrotoxicity favors apoptosis

Expression of apoptosis regulatory genes in chronic cyclosporine nephrotoxicity favors apoptosis. BACKGROUND: Chronic cyclosporine (CsA) nephrotoxicity is characterized by interstitial fibrosis, tubular dropout, and loss of cellularity in areas of fibrosis. Apoptosis was found to play a role in CsA-induced fibrosis. We evaluated the role of the death genes p53, Bax, and Fas-L (ligand), survival gene Bcl-2, interleukin-converting enzyme (ICE), and caspase-3. METHODS: Salt-depleted rats were administered CsA 15 mg/kg/day or vehicle (VH) and were sacrificed at 7 or 28 days. Apoptosis was detected by TdT-mediated dUTP-biotin nick end labeling assay. p53 and Bax expressions were evaluated by Northern and Western blot analysis. Fas-L and Bcl-2 expressions were evaluated by immunofluorescence. In addition to ICE mRNA, caspase-3 enzymatic activity was assayed. RESULTS: Although no differences were seen at one week, apoptosis-positive cells increased with CsA at four weeks (P < 0.05) and correlated with tubular atrophy and interstitial fibrosis (r = 0.8, P < 0.05). CsA induced the expression of p53 (P < 0.05) and Bax (P < 0.01) and decreased that of Bcl-2 (P < 0.05). CsA up-regulated Fas-L expression (P < 0.001). ICE mRNA and caspase-3 activity were also increased (P < 0.01). The changes occurred as early as one week and remained statistically significant at four weeks. CONCLUSIONS: Specific apoptotic genes are increased in chronic CsA nephrotoxicity. The balance favors the induction of apoptosis. Increased apoptosis could explain the tubular dropout and loss of cellularity with fibrosis. This then may impair the ability of the tubulointerstitium to remodel. Apoptosis could also contribute to some of CsA immunosuppressive effects on activated lymphocytes.     

Colon cancer and apoptosis

BACKGROUND: The implementation of new therapeutic options for the management of metastatic colon cancer mandates a revisit to apoptosis and its role in colon cancer tumorigenesis with an emphasis on the mechanisms leading to chemotherapeutic resistance and immune system evasion of colon cancer cells. DATA SOURCES: Literature regarding molecular apoptosis mechanisms and the role of apoptosis in colon cancer progression are reviewed by this article. CONCLUSION: Programmed cell death has rapidly emerged as a potential target for cancer treatment at various stages of tumor progression. Chemoprevention, immuno-regulation, and metastasis are prospective targets by which apoptotic mechanisms could be utilized in the prevention and management of tumorigenesis. Understanding how defects in the death receptor pathway of apoptosis permit colon cancer cells to escape the immune system would allow for treatment options whereby the body's immune system could again recognize and eliminate unwanted cells.     

Androgen-mediated resistance to apoptosis

BACKGROUND: Previous studies demonstrate that androgen is capable of exerting a protective effect in the androgen-sensitive human prostate cancer cell line LNCaP. Limited studies, however, have addressed the underlying mechanisms involved, in particular the effects of androgen on both pro- and anti-apoptotic gene expression. METHODS: We investigated the effects of androgen on apoptotic sensitivity and the expression of the caspases and specific members of the Bcl-2 family in the LNCaP cell line. The effects of androgen on NF-kappaB activation were also investigated by using a gel mobility shift assay. RESULTS: 5alpha-Dihydrotestosterone (5-alphaDHT) conferred resistance to radiation (5 Gy) and etoposide-induced apoptosis in the LNCaP cell line. This finding was associated with a time-dependent decrease in the expression of the caspases and pro-apoptotic Bcl-2 family members. 5-alphaDHT did not confer protection against apoptosis in the LNCaP line transfected with the IkappaB super repressor of NF-kappaB, nor in the androgen insensitive PC-3 and DU-145 cell lines. CONCLUSION: The ability of 5-alphaDHT to raise the apoptotic threshold in the LNCaP cell line by altering specific pro-apoptotic gene expression suggests that androgen may serve as a general survival signal against diverse pathways that ultimately signal for apoptosis. We hypothesize that NF-kappaB serves as an important mediator in androgen survival signaling.     

The X-linked inhibitor of apoptosis protein inhibits taxol-induced apoptosis in LNCaP cells

To clarify the roles of the X-linked inhibitor of apoptosis protein (XIAP), we investigated the effects of XIAP overexpression on taxol-induced cell growth arrest and apoptosis in the prostate cancer cell line (LNCaP). After the transfection of XIAP cDNA into LNCaP cells, we established clonal cell lines that overexpressed XIAP and examined the taxol effects on growth and apoptosis by 2-(4-lodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt and flow cytometric analysis. The effects of XIAP overexpression on caspase-3 were examined by immunoblot analysis and activity assay. The interaction between XIAP and caspase-3 in LNCaP cells was examined by cotransfection with myc-XIAP and caspase-3-HA cDNAs followed by immunoprecipitation and immunoblot analysis. Large amounts of XIAP were expressed in the established cell lines. Although the growth rates were reduced in a dose- and time-dependent manner by taxol, these effects were significantly decreased in XIAP stably overexpressing cell lines. In addition, we found that taxol treatment induced the cleavage of pro-caspase-3, followed by apoptosis, and that the overexpression of XIAP inhibited apoptosis by attenuating the cleavage of pro-caspase-3 and caspase-3 activity. Interestingly, XIAP bound to pro-caspase-3 in LNCaP cells transiently cotransfected with myc-XIAP and caspase-3-HA cDNAs, and this interaction was inhibited by taxol treatment. These results suggest that the overexpression of XIAP inhibits taxol-induced apoptosis through the decrease of caspase-3 activity and inhibition of the processing of pro-caspase-3.     

p53正向细胞凋亡调控因子基因表达改变对关节软骨细胞凋亡的影响

目的 观察p53正向细胞凋亡调控因子基因(PUMA)的表达对关节软骨细胞凋亡的影响.方法 通过白细胞介素(IL)-1β干预建立小鼠骨关节炎模型,再采用小分子RNA干扰片段对小鼠软骨细胞中的PUMA进行抑制,转染前后分别检测PUMA蛋白的表达及细胞凋亡.结果 空转染对照组PUMA蛋白表达量为空白对照组的6.11倍,空转染对照组分别为两个实验组的2.02倍和3.30倍.染色显示细胞凋亡率在空白对照组为3.6％,空转染对照组29.6％,两个实验组分别为9.0％和13.2％,实验组和空转染对照组的差异有统计学意义(P＜0.01),抑制PUMA表达后细胞凋亡明显减少.结论 骨关节炎小鼠软骨细胞中PUMA基因表达增加,提示PUMA基因参与了骨关节炎软骨细胞凋亡.     

前列腺癌细胞凋亡通路基因表达与凋亡反应性的关系

目的　探讨凋亡通路基因表达改变与前列腺癌细胞凋亡反应性的关系。　方法　凋亡诱导剂鬼臼乙叉甙分别作用前列腺癌激素敏感与不敏感细胞LNCaP和PC 3,Hoechst 332 5 8染色检测凋亡发生率。收集LNCaP和PC 3细胞后提取总RNA ,合成cDNA探针并以生物素标记 ,在凋亡通路特异基因寡核苷酸片段cDNA膜上进行杂交反应 ,检测基因mRNA表达。　结果　鬼臼乙叉甙能诱导两种细胞凋亡 ,但PC 3细胞的凋亡反应性小于LNCaP细胞。与LNCaP细胞比较 ,PC 3细胞显著下调的基因为Bcl1 0、CIDE A、GADD4 5a和RIP2 ,以及Caspase 4、5和 6 ,显著上调的基因为TRAF4。两种细胞均强烈表达Caspase 1 4和TNFR2。　结论　凋亡通路基因表达改变与前列腺癌细胞凋亡反应性不同有关 ,在前列腺癌激素敏感性转化中可能有重要作用