食欲素功能研究及在肿瘤治疗方面应用的前景

目的 阐述食欲素的生理功能以及与瘦素和恶性肿瘤的相关性,对其在肿瘤治疗等方面的应用前景进行展望。 方 法 回顾和研究近几年来国内外发表的有关食欲素的生理作用,与瘦素和恶性肿瘤相关性的中英文相关文献。 结果 食欲素 不仅可参与调节能量代谢和摄食行为,还在睡眠 - 觉醒周期、应激、药物成瘾复吸、胰岛素分泌、胃酸分泌等方面有着非 常重要的作用,且已有文献证实食欲素可影响恶性肿瘤患者的食欲和促进恶性肿瘤细胞的凋亡。 结论 食欲素在开发治疗糖 尿病、药物成瘾和嗜睡症的新型药物及改善恶性肿瘤患者食欲和促进恶性肿瘤细胞凋亡方面具有应用前景。     

雷公藤甲素调节PI3K/Akt信号通路抑制结肠癌增殖并诱导凋亡的实验研究

目的 探讨雷公藤甲素抑制结肠癌增殖增殖、诱导凋亡的机制.方法 稳定培养结肠癌HT29细胞,分别加入含25、50、100、200、400、600 mg/L雷公藤甲素的培养基进行干预,采用CCK-8法、流式细胞术、细胞集落形成实验检测雷公藤甲素对HT29细胞增殖和凋亡的影响.构建裸鼠结肠癌移植瘤模型,将30只裸鼠随机分为对...     

冬凌草甲素诱导结肠癌细胞凋亡的机制研究

目的:观察冬凌草甲素(oridonin)对人结肠癌细胞HCT-116和HT-29的凋亡抑制作用,同时探讨其诱导结肠癌细胞凋亡作用的机制.方法:应用Cell-counting kit-8检测冬凌草甲素对HCT-116和HT-29细胞的生长抑制作用及对细胞活力的影响;采用烟酸己可碱(hoechst)33342和碘化丙啶(propidium lodine,PI)荧光染色法,观察冬凌草甲素诱导结肠癌HCT-116和HT-29细胞凋亡的形态学变化;采用总NO检测试剂盒与活性氧(reactive oxygen species,ROS)检测试剂盒检测冬凌草甲素处理HCT-116和HT-29细胞时,细胞内NO与ROS水平的变化;同时应用ROS阻断剂N-乙酰基半胱氨酸(N-acetyl-cysteine,NAC)预处理HCT-116、HT-29细胞后再加入冬凌草甲素,观察细胞凋亡情况.结果:冬凌草甲素可明显抑制HCT-116和HT-29细胞的增殖、降低细胞活力;Hoechst 33342和PI双荧光染色发现冬凌草甲素可诱导HCT-116和HT-29细胞的凋亡.虽然冬凌草甲素不能改变HCT-116、HT-29细胞内的NO水平,但是可提高HCT-11和HT-29细胞内ROS水平;ROS阻断剂NAC可阻断冬凌草甲素诱导HCT-116和HT-29细胞凋亡. 结论:冬凌草甲素通过提高ROS水平诱导HCT-116和HT-29细胞的凋亡.     

冬凌草甲素诱导结肠癌细胞凋亡的实验研究

目的　观察冬凌草甲素体外诱导人结肠癌HCT8细胞凋亡的作用。方法　利用光镜及流式细胞仪观察不同浓度冬凌草甲素诱导结肠癌HCT8细胞凋亡的作用。结果　冬凌草甲素可诱导HCT8细胞凋亡 ,且凋亡率随着浓度的增加而增加。结论　冬凌草甲素对HCT8细胞株具有体外抗肿瘤作用 ,其作用机制与诱导凋亡有关     

冬凌草甲素诱导结肠癌细胞凋亡的实验研究

目的 观察冬凌草甲素体外诱导人结肠癌HCT8细胞凋亡的作用。方法 利用光镜及流式细胞仪观察不同浓度冬凌草甲素诱导结肠癌HCT8细胞凋亡的作用。结果 冬凌草甲素可诱导HCT8细胞凋亡，且凋亡率随着浓度的增加而增加。结论 冬凌草甲素对HCT8细胞株具有体外抗肿瘤作用，其作用机制与诱导凋亡有关。     

逆转录病毒介导的凋亡素基因诱导人结肠癌细胞Lovo的凋亡

目的 构建强力霉素诱导型重组凋亡素基因逆转录病毒载体,观察强力霉素诱导凋亡素基因表达的情况及对人结肠癌细胞的影响。方法 构建重组逆转录病毒表达载体pRevTRE-VP3。调节载体pRevTet-on和表达载体pRevTRE-VP3分别转染PT67包装细胞后,收集包装好的病毒依次感染人结肠癌细胞系Lovo,用抗生素筛选出抗性细胞株Lovo/on-vp3。通过向培养液中加入或去除强力霉素调控凋亡素基因在Lovo/on-vp3细胞中的表达,Annexin V-FITC/PI双染色后,以流式细胞仪检测细胞凋亡率。结果 经酶切和测序鉴定,重组逆转录病毒载体pRevTRE-VP3构建成功,并添加了kozak序列。筛选出可经四环素调控凋亡素基因表达的人结肠癌细胞株Lovo/on-vp3,经PCR和RT-PCR证实凋亡素基因已整合入细胞DNA,并得到了表达;Lovo/on-vp3细胞在1mg/L强力霉素培养环境中培养24h、48h和72h凋亡率明显高于无强力霉素环境中相同时间点的细胞凋亡率,两者差异有显著性。结论 凋亡素基因经RevTet系统导入人结肠癌细胞Lovo后,在强力霉素诱导下可表达凋亡素蛋白并诱导Lovo细胞凋亡。并随诱导时间延长凋亡素蛋白表达增加、细胞凋亡增多。     

芹菜素对人结肠癌细胞SW480增殖抑制作用的实验研究

目的:观察芹菜素对体外培养的人结肠癌SW480细胞的增殖抑制作用.方法:观察不同浓度[(10、30、60、90)μmol/L]的芹菜素在(24、48、72)h对人结肠癌SW480细胞增殖的影响:光学显微镜和电子显微镜观察芹菜素处理后人结肠癌SW480细胞形态结构的变化;运用四唑盐比色法(MTY)检测芹菜素对人结肠癌SW480细胞生长的影响.结果:经芹菜素处理的人结肠癌SW480细胞数量减少,部分细胞体积缩小,细胞膜完整,胞浆浓缩,核染色质固缩,细胞核碎裂,形成凋亡小体;MTT法检测显示芹菜素对人结肠癌SW480细胞的增殖有抑制作用,其抑制作用随着作用浓度的增加和作用时间的延长而增强.结论:芹菜素对人结肠癌SW480细胞的增殖有抑制作用,是一种高效低毒的药物.     

藏红花素诱导宫颈癌HeLa细胞凋亡及其作用机制

目的:研究藏红花素对HeLa细胞的促凋亡作用和机制.方法:设置0、02、0.4及0.8 mmol/L 4个浓度梯度,MTT法分析不同浓度藏红花素对HeLa细胞增殖的影响;设置空白阴性对照及秋水仙素(10 μg/L)阳性对照,向HeLa细胞培养物分别加入0.4和0.8 mmol/L的藏红花素,培养48 h后用PI/AnnexinⅤ双染法分析其凋亡情况;1.6 mmol/L藏红花素作用于HeLa细胞72 h后,蛋白质印迹法检测Caspase-3的切割.结果:MTT实验分析显示,在0、0.2、0.4及0.8 mmol/L浓度下HeLa细胞存活率分别为1、0.964、0.796和0.586.藏红花素显著地抑制HeLa细胞生长,P<0.05;各浓度组间均差异有统计学意义,P<0.05.PI/Annexin V双染法、流式细胞仪检测显示,阴性对照组、10μg/L秋水仙素阳性对照组、0.4及0.8 mmol/L藏红花素处理组的细胞凋亡率分别为3.64%、15.99%、4.86%和9.28%,藏红花素促进HeLa细胞凋亡.蛋白质印迹法检测显示,藏红花素促进HeLa细胞Caspase-3切割.结论:藏红花素可明显地抑制HeLa细胞生长,并通过增加HeLa细胞Caspase-3切割促进其凋亡.     

糖化重组生存素腺病毒疫苗抗肿瘤作用的实验研究

背景与目的：生存素在调控细胞凋亡和有丝分裂过程中起着重要作用,在正常分化的组织中不表达或表达极低,而在胚胎组织和大部分肿瘤组织中广泛表达,而这一特点为恶性肿瘤的基因治疗提供了很好的靶标.本研究制备糖化重组生存素腺病毒疫苗,观察其抗肿瘤作用并探讨其作用机制.方法：将重组生存素腺病毒和甘露聚糖在氧化条件下偶联,同时建立小鼠结肠癌和Lewis肺癌模型,以糖化重组生存素腺病毒疫苗治疗荷瘤小鼠,观察肿瘤体积和小鼠生存时间.对小鼠肿瘤组织作TUNEL染色观察肿瘤细胞凋亡.为了检测疫苗的保护作用,预先以糖化重组生存素腺病毒疫苗免疫接种小鼠,或合用抗CD4、CD8和NK单克隆抗体阻断相应的淋巴细胞亚群,再接种肿瘤,观察小鼠肿瘤生长情况.结果：糖化重组生存素腺病毒疫苗治疗组小鼠肿瘤生长受到明显抑制,无明显不良反应发生,小鼠的生存时间明显延长,肿瘤细胞凋亡明显增加.同时,糖化重组生存素腺病毒疫苗能诱导小鼠产生抗肿瘤免疫,这一免疫反应依赖于CD4和CD8淋巴细胞,也部分依赖于NK细胞.结论：糖化重组生存素腺病毒疫苗能诱导机体产生特异性的主动免疫反应,诱导肿瘤细胞凋亡,具有明确的抗肿瘤作用,值得进一步研究.     

凋亡素诱导人成骨肉瘤细胞多药耐药株凋亡的研究

目的:研究凋亡素对人成骨肉瘤细胞0S-732多药耐药株R-OS-732的作用.方法:凋亡素基因VP3经酶切后克隆入质粒pIRES1,获得重组质粒pIRVP3,通过脂质体法pIRVP3转染R-0S-732细胞,RT-PCR检测凋亡素在细胞中的表达;光镜及电镜下观察瘤细胞;提取瘤细胞基因组DNA进行琼脂糖凝胶电泳;流式细胞仪检测凋亡率.结果:凋亡素基因已在转录水平表达;光镜及电镜下两组细胞形态变化明显;电泳见转染组DNA呈梯状条带,对照组为单一条带;转染组凋亡率明显高于空白对照组(P＜0.01).结论:凋亡素可有效诱导R-OS-732细胞凋亡.     

Aberrant expression of OX1 receptors for orexins in colon cancers and liver metastases: an openable gate to apoptosis

Resistance to apoptosis is a recurrent theme in colon cancer. We have shown previously that the 7-transmembrane spanning receptor OX1R for orexins promotes robust apoptosis in the human colon cancer cell line HT29 through an entirely novel mechanism involving phosphorylation of tyrosine-based motifs in OX1R. Here, we investigated the status of OX1R in a large series of human colorectal tumors and hepatic metastases. All primary colorectal tumors regardless of their localization and Duke's stages and all hepatic metastases tested expressed OX1R mRNA and/or protein. In sharp contrast, adjacent normal colonocytes or hepatocytes as well as control normal tissues were negative. Next, we showed that nine human colon cancer cell lines established from primary tumors or metastases expressed OX1R mRNA and underwent important apoptosis on orexin-A challenge. Most interestingly, orexin-A also promoted robust apoptosis in cells that are resistant to the most commonly used drug in colon cancer chemotherapy, 5-fluorouracil. When human colon cancer cells were xenografted in nude mice, orexin-A administered at day 0 strongly slowed the tumor growth and even reversed the development of established tumors when administered 7 days after cell inoculation. Orexin-A also acts by promoting tumor apoptosis in vivo because caspase-3 is activated in tumors on orexin treatment of nude mice. These findings support that OX1R is an Achilles heel of colon cancers, even after metastasis or chemoresistance. They suggest that OX1R agonists might be novel candidates for colon cancer therapy.     

Stat3信号转导通路调控Caspase-3表达促进结肠癌细胞凋亡的机制

目的本研究探讨Stat3/Caspase-3信号转导通路调控结肠癌细胞凋亡的作用机制。方法用阳离子脂质体介导Stat3反义寡核苷酸转染人结肠癌HT29细胞,MTT法检测细胞增殖状态;流式细胞术检测细胞周期与凋亡;Westernblot检测Stat3、p-Stat3、Caspase-3与Bcl-2凋亡家族成员Bcl-2和Bcl-xL的表达。结果转染Stat3反义寡核苷酸后HT29细胞增殖受抑制,凋亡细胞增多,Stat3,p-Stat3与Caspase-3表达下降,Bcl-2与Bcl-xL变化不明显。结论阻断Stat3通路可以抑制靶基因Caspase-3表达并诱导结肠癌细胞凋亡。     

Ku70乙酰化修饰介导曲古霉素A（TSA）促结肠癌细胞凋亡的作用机制研究

目的:探讨Ku70乙酰化修饰介导曲古霉素A（TSA）促结肠癌细胞凋亡的作用和机制。方法:选取结肠癌HCT116细胞和SW620细胞,体外培养并采用浓度梯度TSA处理。MTT法观察TSA对细胞的IC50和活力的影响;Western blot和免疫荧光染色观察TSA对结肠癌HCT116细胞和SW620细胞中Ku70、acetyl-Ku70蛋白水平及胞内分布的影响;流式细胞术检测TSA对结肠癌HCT116细胞和SW620细胞凋亡的影响;Western blot检测TSA对结肠癌HCT116细胞和SW620细胞中凋亡相关蛋白Caspase-3、Bax和Bcl-2表达的影响。结果:MTT结果显示TSA可浓度依赖性抑制结肠癌HCT116细胞和SW620细胞活力且其IC50值分别为1.023 μmol/L和1.076 μmol/L（P<0.05）;Western blot和免疫荧光染色结果显示TSA可显著上调结肠癌HCT116细胞和SW620细胞中acetyl-Ku70的蛋白水平并促进其核转入（P<0.05）;流式细胞术结果表明TSA可促进结肠癌HCT116细胞和SW620细胞凋亡（P<0.05）;此外,Western blot结果显示TSA可明显上调结肠癌HCT116细胞和SW620细胞中凋亡蛋白Caspase-3和Bax的表达,下调抗凋亡蛋白Bcl-2的表达（P<0.05）。结论:结肠癌HCT116细胞和SW620细胞中,TSA可能通过增强Ku70乙酰化并促进其核转入,发挥促凋亡作用,为以Ku70翻译后修饰调控为靶点的肿瘤治疗提供新策略和理论依据。     

15-hydroxy-eicosatetraenoic acid arrests growth of colorectal cancer cells via a peroxisome proliferator-activated receptor gamma-dependent pathway

Peroxisome proliferator-activated receptor gamma (PPARgamma) inhibits cell growth via promoting apoptosis. Human colorectal cancer tissues had abundant PPARgamma but the incidence of apoptosis was very low, suggesting a defect in the PPARgamma pathway. Here, we found that 15-hydroxy-eicosatetraenoic acid (15S-HETE), an endogenous ligand for PPARgamma, was significantly decreased in the serum of patients with colorectal cancer. Treatment of colon cancer cells with 15S-HETE inhibited cell proliferation and induced apoptosis, which was preceded by an increase in TGF-beta-inducible early gene (TIEG) and a decrease in Bcl-2. The action of 15S-HETE could be blocked when PPARgamma was suppressed. Overexpression of Bcl-2 prevented the apoptosis. The levels of TIEG and 15-lipoxygenase (15-LOX), the enzyme responsible for 15S-HETE production, was decreased in colorectal cancer. Therefore, colorectal cancer is associated with decreased 15S-HETE. Treatment of colon cancer cells with 15S-HETE inhibits cell proliferation and induces apoptosis in a PPARgamma-dependent pathway involving augmentation of TIEG and reduction of Bcl-2 expression.     

Cisplatin-induced CD95 redistribution into membrane lipid rafts of HT29 human colon cancer cells

We have shown previously that the death receptor CD95 could contribute to anticancer drug-induced apoptosis of colon cancer cells. In addition, anticancer drugs cooperate with CD95 cognate ligand or agonistic antibodies to trigger cancer cell apoptosis. In the present study, we show that the anticancer drug cisplatin induces clustering of CD95 at the surface of the human colon cancer cell line HT29, an event inhibited by the inhibitor of acid sphingomyelinase (aSMase) imipramine. The cholesterol sequestering agent nystatin also prevents cisplatin-induced CD95 clustering and decreases HT29 cell sensitivity to cisplatin-induced apoptosis and the synergy between cisplatin and anti-CD95 agonistic antibodies. CD95, together with the adaptor molecule Fas-associated death domain and procaspase-8, is redistributed into cholesterol- and sphingolipid-enriched cell fractions after cisplatin treatment, suggesting plasma membrane raft involvement. Interestingly, nystatin prevents the translocation of the aSMase to the extracellular surface of plasma membrane and the production of ceramide, suggesting that these early events require raft integrity. In addition, nystatin prevents cisplatin-induced transient increase in plasma membrane fluidity that could be required for CD95 translocation. Together, these results demonstrate that cisplatin activates aSMase and induces ceramide production, which triggers the redistribution of CD95 into the plasma membrane rafts. Such redistribution contributes to cell death and sensitizes tumor cells to CD95-mediated apoptosis.     

Induction of apoptosis in colon cancer cells by cyclooxygenase-2 inhibitor NS398 through a cytochrome c-dependent pathway.

Nonsteroidal anti-inflammatory drugs (NSAIDs) have shown cancer preventive activity in patients who took them frequently. These drugs can induce tumor cells to undergo apoptosis in vitro. NS398, a cyclooxygenase-2 (COX-2)-selective inhibitor, has been reported to cause apoptosis in cancer cell lines. Therefore, we examined its effect on 15 human colon cancer cell lines and investigated its mechanism of action. NS398 decreased cell viability in all of the cell lines. Tumor cells that expressed COX-2 were shown to be more sensitive to NS398 treatment. In three selected colon cancer cell lines, NS398-induced apoptosis was mediated by the release of cytochrome c from mitochondria and, consequently, by the activation of caspase-9 and caspase-3 and by the cleavage of poly(ADP-ribose) polymerase. In contrast, caspase-8 was not involved in NS398-induced apoptosis, which suggested that the cytochrome c pathway may play an important role in NS398-induced apoptosis in colon cancer cell lines. Therefore, the combination of NS398 with apoptosis-inducing drugs through cytochrome c-independent pathways may be warranted.     

microRNA-224对缺氧诱导结肠癌细胞凋亡的影响

目的:通过结肠癌细胞实验检测microRNA-224在结肠癌发生发展过程中的作用。方法:建立缺氧导致结肠癌细胞凋亡的模型,细胞计数盒(Cell Counting Kit-8,CCK-8)法检测结肠癌细胞活力;Annexin/PI流式细胞术检测结肠癌细胞凋亡率的变化。Annexin/PI流式细胞术检测转染microRNA-224后结肠癌细胞凋亡的变化。蛋白免疫印迹检测转染microRNA-224后凋亡蛋白Caspase-3的变化。结果:凋亡率在缺氧的结肠癌细胞组高于正常结肠癌细胞组(P<0.05);缺氧诱导凋亡组转染microRNA-224后凋亡率低于空质粒对照组(P<0.05);在缺氧诱导凋亡组中转染microRNA-224,凋亡相关蛋白Caspase-3 的表达低于对照组(P<0.05)。结论:microRNA-224可抑制结肠癌细胞凋亡,结肠癌细胞的凋亡失衡在结肠癌的发生发展过程中具有重要意义。     

Med-19对结肠癌细胞增殖及凋亡的影响

背景与目的:Med-19目前被定义为肿瘤转移相关基因,但对其在结肠癌中的功能还知之甚少。本文旨在检测Med-19基因在结肠癌中的表达及其与临床病理参数间的相关性,观察Med-19对结肠癌细胞增殖和凋亡的影响。方法:利用免疫组化检测Med-19基因在115例结肠癌中的表达情况;构建Med-19-siRNA载体转染结肠癌caco-2细胞,MTT法检测癌细胞的增殖活性,流式细胞术分析细胞凋亡的变化。结果:Med-19基因在结肠癌中的表达阳性率为64.3%,远远高于相应癌旁组织的27.8%,差异有统计学意义(P<0.05)。深入分析发现Med-19基因的表达水平与Dukes分期、淋巴结转移密切相关,而与年龄、性别、分化程度无关。与空载体转染组相比,MTT结果表明,Med-19-siRNA载体转染的caco-2细胞生长明显受到抑制,差异有统计学意义(P<0.05),流式细胞术结果提示,Med-19-siRNA载体转染的caco-2细胞凋亡比例升高,差异有统计学意义(P<0.05)。结论:Med-19基因在结肠癌中高表达,下调Med-19基因的表达可抑制结肠癌细胞增殖,促进结肠癌细胞凋亡,提示Med-19基因可以作为结肠癌治疗的潜在基因靶点。