自噬基因Beclin1在宫颈癌中的研究进展

自噬是指从粗面内质网无核糖体附着区脱落的双层膜包裹部分胞质和细胞内需降解的大分子物质（如蛋白质、RNA、过量储存的糖原等）,以及一些细胞内源性底物（包括因生理或病理引起衰老、破损的细胞器）等成分形成自噬体后与溶酶体融合成自噬溶酶体,降解所包裹内容物以实现细胞本身代谢和某些细胞器的更新。但自噬过度上调后可引起细胞死亡,即自噬性细胞死亡。     

miRNA-216b通过靶向调控Beclin1对顺铂诱导的胃癌细胞自噬及凋亡的影响

目的:探究miRNA-216b(miR-216b)对顺铂处理的胃癌细胞的影响及其可能的作用机制.方法:体外培养人胃黏膜细胞系GES-1、人胃癌细胞系SGC7901和胃癌顺铂耐药细胞系SGC7901/DDP,将SGC7901/DDP细胞随机分为空白对照组、agomir-NC+ oe-NC组、agomir-miR-216b...     

Beclin1调控自噬、凋亡与炎症反应的分子机制

<正>自噬和凋亡作为两种不同的程序性细胞死亡方式,存在着复杂的相互作用。凋亡是组织器官生长过程中最基本的重构机制,其在组织抵御内、外源性损伤过程中发挥重要作用,可保护细胞、组织器官免受坏死诱导的炎性反应损伤;自噬,细胞自我吞噬过程,是细胞在危机状态下重新利用细胞结构并产生能量物质的主要生存机制〔1〕。自噬与凋亡的生化代谢途径及形态学虽存在显著差异,但功能密切联系,共同调控细胞生存和死亡。此外,在严重应激反应中,自噬功能紊乱可激活炎性小     

KAI1对人胰腺癌MiaPaCa-2细胞自噬的影响

目的 观察感染Ad5-KAI1前后人胰腺癌细胞MiaPaCa-2自噬水平的变化,并初步探讨其机制.方法 应用无KAI1表达的人胰腺癌细胞MiaPaCa2,通过感染带有KAI1目的基因的复制缺陷型腺病毒Ad5-KAI1使细胞表达KAI1,以Ad5 -null感染作为阴性对照,亲本细胞为空白对照.用透射电镜观察细胞自噬小体,共聚焦显微镜观察自噬标志LC3颗粒.应用阻断剂PD98059和LY294002干预细胞,蛋白质印迹法检测自噬相关蛋白beclin 1、LC3-Ⅱ、LC3-Ⅰ及ERK-1/2、磷酸化ERK-1/2(p-ERK-1/2)、AKT、p-AKT的表达.结果 以100 MOI Ad5-KAI1感染细胞24h,表达KAI1蛋白的细胞达(84.97±8.56)％;LC3颗粒从4个左右增加到20个以上;细胞线粒体肿胀、变性,胞质内双层膜样结构增加;Beclinl表达增加(1.4±0.3)倍,LC3-Ⅱ/LC3-Ⅰ表达增加(8.00 ±2.78)倍.PI3K阻断剂LY294002预处理细胞后可以有效地抑制MiaPaCa-2细胞AKT的磷酸化(2.756降至1.516),但不能抑制LC3-Ⅱ/LC3-Ⅰ比值的增加(0.770增加到1.403).ERK阻断剂PD98059预处理细胞后不仅可以有效地抑制MiaPaCa-2细胞ERK的磷酸化(1.637降至0.403),而且可以抑制beclin 1蛋白表达的上调(2.377降至1.150)和LC3-Ⅱ/Lc3-Ⅰ比值的增加(2.225降至0.680).结论 KAI1明显促进MiaPaCa2细胞内自噬,它是通过ERK而不是AKT磷酸化途径促进自噬的.     

肿瘤转移抑制基因KAI1诱导的自噬通过下调Caspase-3活化抑制凋亡

目的 观察KAI1基因诱导的自噬在人胰腺癌MiaPaCa-2细胞中调节凋亡的分子途径.方法 实验分为用细胞外调节蛋白激酶( ERK)的磷酸化阻断剂PD98059预处理组、Caspase-3的活化阻断剂VAD-FMK预处理组和未用PD98059、VAD-FMK预处理组3大组;每大组再分3小组进行不同处理,感染腺病毒空载体AD5-null对照组、感染人KAI1基因的重组腺病毒载体AD5-KAI1组和用自噬阻断剂3 MA预处理阻断自噬后再感染AD5-KAI1组.通过膜朕蛋白V-异硫氰酸荧光素(FITC)/碘化丙啶(PI)双染法检测细胞凋亡,流式细胞术评价Caspase-3活化水平,Western印迹检测ERK磷酸化水平和PARP蛋白的裂解情况.结果 感染AD5-KAI1后癌细胞表达KAI1蛋白的同时绿色荧光蛋白(GFP) LC3绿色颗粒增加,Caspase-3活化、PARP-1裂解、ERK磷酸化和凋亡均明显增多.自噬阻断剂3-MA预处理后,凋亡率由(63.0±7.9)％升至(88.0±4.5)％,Caspase-3活化由(34.0±2.8)％升至(44.2±4.0)％,同时PARP-1裂解更多.Caspase-3阻断剂VAI-FMK预处理可完全抑制3-MA预处理导致的促凋亡作用.ERK磷酸化抑制剂PD98059不能抑制3 MA预处理导致的促凋亡作用.结论 KAI1诱导的自噬通过抑制细胞中Caspase-3活化和PARP裂解而不是通过抑制ERK磷酸化来拮抗KAI1诱导的凋亡.     

汉防己甲素诱导人胃癌BGC-823细胞自噬和凋亡的作用及机制

目的 观察汉防己甲素诱导人胃癌BGC-823细胞自噬与凋亡的作用,并探讨两者发生以及相互关联的分子机制.方法 用不同浓度的汉防己甲素作用于人胃癌BGC-823细胞,用四甲基偶氮唑盐比色法(MTT法)检测细胞增殖率;流式细胞术检测细胞凋亡情况;Western-blot法检测各组细胞Bcl-2和自噬标记蛋白LC3、Beclin1的表达,MDC自噬特异性染料荧光染色观察自噬泡的聚集.结果 TET对BGC-823细胞的生长有显著抑制作用,呈明显的时间、剂量依赖性;TET可诱导BGC-823细胞发生凋亡;TET可诱导BGC-823细胞发生自噬,自噬作用在8、10 μg/mL TET给药组达到高峰,后随着浓度的增加逐渐下降;在TET给药前用3-甲基腺嘌呤(3-MA)阻断自噬后,低浓度(8 μg/mL) TET诱导的凋亡率明显升高;高浓度(20 μg/mL) TET诱导的凋亡率差别无统计学意义.结论 TET能明显抑制人胃癌BGC-823细胞的生长,并诱导其发生凋亡和自噬.TET诱导的自噬作为保护性机制,可发挥拮抗凋亡的作用.     

自噬对三氧化二砷所致正常淋巴细胞损伤的保护效应

目的研究三氧化二砷(As2O3)致外周血淋巴细胞(PBL)损伤中自噬与凋亡的作用。方法应用密度梯度离心法从正常人外周血中分离淋巴细胞,MTT法检测细胞增殖活性;Annexin-V/PI双标记染色检测凋亡;电镜观察细胞形态学改变;单丹磺酰尸胺(MDC)荧光染色观察细胞自噬水平;流式细胞术(FCM)检测Bcl-2的表达水平。结果 1.0⁸.0μmol/L As2O3呈剂量、时间依赖性地抑制人PBL增殖和诱导凋亡,24 h和48 h的IC50分别为12.46μmol/L和3.76μmol/L,并可诱导细胞发生自噬活化。用3-甲基腺嘌呤(3-MA)抑制细胞自噬可增强As2O3对PBL的抑制效应,24 h和48 h的IC50分别为10.40μmol/L和2.31μmol/L,细胞出现显著凋亡形态学改变,凋亡率明显增高,Bcl-2的表达水平降低。结论自噬可作为一种保护机制来抵御As2O3对外周血淋巴细胞的损伤,3-MA可能通过下调Bcl-2的表达而增加As2O3对外周血淋巴细胞的损伤效应。     

Beclin 1与mTOR对心肌缺血/再灌注损伤中自噬的交互调控机制

自噬是一个进化上高度保守的受损或功能障碍的蛋白质聚集体或细胞器降解的过程。在心肌缺血/再灌注(I/R)过程中,可以通过多种因素诱导细胞的自噬活动,而且越来越多的证据表明,自噬在心肌缺血/再灌注损伤(MIRI)中可能起“双刃剑”的作用,适度自噬可促进细胞存活;而不适当的激活自噬可能会加速细胞死亡。Beclin 1介导的自噬/凋亡互反馈信号通路和哺乳动物雷帕霉素靶蛋白(mTOR)介导的自噬与mTOR的互反馈信号通路,是两条经典的自噬激活信号途径,也可能是调控自噬“双刃剑”转向促进细胞存活的重要调控机制。本文将重点综述上述两条信号通路对自噬的交互式调控作用。速发挥作用。因此,Z盘部位实质上成为心肌细胞中的信号转导中心。     

黄芪甲苷对缺血再灌注诱导的大鼠心肌损伤及细胞自噬的调节作用

目的观察黄芪甲苷对缺血再灌注模型损伤大鼠心肌组织的保护作用及与心肌组织细胞自噬的关系。方法结扎大鼠左冠状动脉前降支建立心肌缺血再灌注损伤模型,采用细胞生物学及免疫组织化学法,观察心肌组织在缺血再灌注损伤模型及黄芪甲苷处理后的心肌组织损伤、细胞自噬的变化。结果缺血再灌注损伤使大鼠心肌组织中心肌灶性病变严重,兼有波浪改变及大片炎症细胞浸润,与假手术组相比损伤面积明显增多(P<0.05),而黄芪甲苷低、高剂量组均可使心肌灶性病变和炎症细胞浸润的面积明显减少(P<0.05)。Western blot结果显示,缺血再灌注损伤可激活心肌组织细胞中Beclin1的表达(P<0.05),而黄芪甲苷低、高剂量组均可降低缺血再灌注损伤诱导的心肌组织细胞Beclin1表达(P<0.05)。结论黄芪甲苷可在一定程度上减少缺血再灌注损伤的心肌面积,其机制可能是通过调节与自噬相关的Beclin1细胞信号转导通路而发挥作用。     

三氧化二砷诱导肝癌HepG2细胞凋亡作用

目的 探讨三氧化二砷（As2O3）诱导肝癌HepG2细胞凋亡作用。方法 应用普通光学显微镜、荧光显向镜和流式细胞仪观察As2O3对HepG2细胞株的形态学改变和诱发凋亡率。结果 As2O3作用于细胞后,可看到较典型的细胞凋亡形态学改变,细胞体积缩小,染色质固综合成斑块状,呈半月型紧贴于核膜周边,核碎裂,凋亡小体形成等,AO/EB荧光染色法显示。细胞凋亡率为4.3%-9.1%.As2O3诱导HepG2细胞凋亡作用呈时间依赖性,最佳浓度为2umol/L。流式细胞仪DNA直方图上呈现典型的亚二倍体凋亡峰。As2O3主要作用于细胞周期的G2/M期。结论 As2O3具有诱导HepG2细胞凋亡作用,存在治疗肝癌的潜在价值。     

microRNA expression alteration after arsenic trioxide treatment in HepG-2 cells

Background and Aim: More and more microRNA (miRNA) are found to be involved in tumor genesis and progress. Arsenic trioxide has been an effective chemotherapeutic drug in cancer therapy for many years. In this study, we aimed to find the miRNA involved in the mechanisms of arsenic trioxide treatment in cancer therapy. Methods: We detected the expression profile of miRNA by miRNA microarray and quantitative real‐time polymerase chain reaction. Cell viability assay, flow cytometry analysis, prediction of miRNA targets, Western blot analysis and luciferase reporter assay were carried out to determine the role of one selected miRNA, namely mir‐29a, in affecting the biological behaviors of HepG‐2 cells. Results: Among the 677 human miRNA in the microarray, five miRNA were upregulated and four were downregulated in HepG‐2 cells treated with arsenic trioxide compared to their controls. If only changes above two folds were considered, four miRNA were identified, namely miR‐24, miR‐29a, miR‐30a and miR‐210, which were all upregulated. Among them, miR‐29a showed a positive therapeutic effect in liver cancer cells by inhibiting cell growth and inducing cell apoptosis, and PPM1D was confirmed to be the target gene of miR‐29a. Furthermore, a synergy effect was detected between miR‐29a and arsenic trioxide. Conclusions: Arsenic trioxide altered miRNA expression profile in HepG‐2 cells. Among the altered miRNA, miR‐29a seemed to take a role in the mechanism of arsenic trioxide in liver cancer therapy. The synergy effect between miR‐29a and arsenic trioxide may offer this drug a new chance in cancer therapy by decreasing its dose and toxic side‐effects.     

氧化砷诱导食管癌细胞系细胞凋亡的形态学研究

目的在氧化砷（As2O3）作用于食管癌细胞株EC8712过程中，用光镜和电镜观察培养细胞凋亡的形态改变方法ECh712于199培养基常规培养，以3μmolAs2O3作用于细胞，72h收获细胞，作光镜（HE染色，TUNEL标记）、透射电镜和流式细胞仪检查.结果3μmolAs2O3作用72h，出现许多凋亡细胞，培养细胞部分变圆，脱落.在光镜下HE染色观察2种凋亡细胞.一种核小；圆形，致密呈固缩核、和核碎,另一种胞质红染，染色质凝集，二者TUNEL标记阳性．流式细胞仪检测有凋亡峰出现（亚G1／G0峰）．电镜检查有二种凋亡类型.一呈典型凋亡细胞核改变；在早期染色质凝集成块状，细胞器保存完好.第二期，随着染色质改变，细胞核变圆，饱满，核膜完整，染色质靠边，大块染色质，构成车轮状或半月状.核膜变性解体，使染色质逸出．最后细胞变性坏死.凋亡小体易见，小块状球状，膜包或裸露.另一种固缩细胞，细胞皱缩，胞质致密，核电子密度高.结论光镜和电镜检查结果证实As2O3可以诱导食管癌细胞系ECh712细胞凋亡，因此As2O3可作为食管癌辅助治疗药物．     

氧化砷诱发胃癌细胞株凋亡的初步研究

目的在三氧化二砷（Ａｓ２Ｏ３）治疗ＡＰＬ的基础上，进一步探讨Ａｓ２Ｏ３能否诱发胃癌细胞株凋亡。方法采用荧光标记法，经流式细胞仪和荧光显微镜观察Ａｓ２Ｏ３对ＭＫＮ４５和ＳＧＣ７９０１胃癌细胞株的凋亡诱发率和形态学改变。结果发现Ａｓ２Ｏ３诱发胃癌细胞凋亡率高于５－Ｆｕ的作用；形态学见凋亡细胞呈荧光标记阳性，细胞内出现斑块状荧光，体积缩小。结论Ａｓ２Ｏ３可诱发胃癌细胞凋亡，有必要进一步探索其对胃癌治疗的价值。     

氧化砷诱导胃癌细胞凋亡的信号传导途径研究

目的 检测氧化砷(As2O3)诱导胃癌细胞株(SGC-7901和MKN-45)凋亡过程中cAMP、蛋白激酶C(PKC)和酪氨酸蛋白激酶(PTK)活性变化，以探讨其诱导胃癌细胞凋亡过程中可能存在的信号传导途径。方法 应用钙离子拮抗剂、PKC和PTK抑制剂研究其对AS2O3诱导胃癌细胞凋亡过程的影响，以TUNEL法检测细胞凋亡率。以放射免疫法测定As2O3作用前后细胞内cAMP水平的变化。抽提PKC和PTK蛋白，以Lowry法测定As2O3作用前后各自蛋白表达水平的变化。结果 钙离子拮抗剂对As2O3诱导胃癌细胞凋亡过程没有影响，PKC和PTK抑制剂不仅本身能诱导胃癌细胞凋亡，且对As2O3诱导胃癌细胞凋亡具有协同作用。在As2O3诱导胃癌细胞凋亡过程中存在cAMP浓度增高和PKC、PTK活性显著降低，提示cAMP、PKC和PTK可能参与As2O3诱导胃癌细胞凋亡的作用。结论 PKC和PTK抑制剂可以通过影响信号传导系统诱导胃癌细胞凋亡，并能促进As2O3诱导胃癌细胞凋亡。     

Induction of apoptosis by arsenic trioxide and hydroxy camptothecin in gastriccancer cells in vitro

AIM To study the effects of arsenic trioxide and HCPT on different degrees of differentiated gastric cancer cells (SGC-7901, MKN-45, MKN-28)with respect to both cytotoxicity and induction of apoptosis in vitro. ~ODS The cytotoxicity of As2O3 and HCPT on gastric cancer cells was determined by MTTassay. Morphologic changes of apoptosis of gastric cancer cells were observed by light microscopy and transmission electron microscopy. Apoptosis and cell cycle changes of gastric cancer cells induced by HCPT and As2O3 were investigated by TUNEL method and flow cytometry. RESULTS As2O3 and HCPT had remarkable cytotoxic effects on different degrees of differentiated gastric cancer cells. The IC50 of As2O3 on well differentiated gastric cancer cell MKN-28, moderately differentiated gastric cancer cell SGC-7901, and poorly differentiated gastric cancer cell MKN-28 were 8. 91 μmol/L, 10. 57 μmol/L, and 11.65 μmol/L, respectively. The IC50 of HCPT on MKN-28, SGC-7901, and MKN-45 were 9. 35 rg/L, 10. 21 rg/L, and 12. 63 mg/L respectively after 48 h treatment. After 12 h of exposure to both drugs, gastric cancer cells exhibited morphologic features of apoptosis, including cell shrinkage, nuclear condensation,and formation of apoptotic bodies. A typical subdiploid peak before G0/G1 phase was observed by flow cytometry. The apoptotic rates of SGC7901, MKN-45, and MKN-28 were 13. 84%, 22.52%, and 9. 68%, respectively after 48 h exposure to 10 μmol/L As2O3. The apoptotic rates of SGC-7901, MKN-45, and MKN-28 were 21.88%, 12.35%, and 30. 26%, respectively after 48 h exposure to 10 mg/L HCPT. The apoptotic indice were 7% - 15% as assessed by TUNEL method. The effect of As2O3 on SGC-7901 showed remarkable cell cycle specificity, which induced cell death in G1 phase, and blocked G2/M phase. HCPT also showed a remarkable cell cycle specificity, by inducing cell death and apoptosis in G1 phase and arrest of proliferation at S phase. CONCLUSION AS2O3 and HCPT exhibit significant cytotoxicity on gastric cancer cells by induction of apoptosis. As2O3 and HCPT might have a promising prospect in the treatment of gastric cancer, which needs to be further studied.     

氧化砷诱导胃癌细胞凋亡的实验研究

目的 研究三氧二化砷（氧化砷）对胃癌细胞的诱导凋亡作用。方法 应用ＴＵＮＥＬ染色、流式细胞仪技术研究氧化砷对胃癌细胞ＭＫＮ－４５、ＭＫＮ－２８的诱导凋亡作用。结果 氧化砷作用于不同分化程度的胃癌细胞后,可看到较为典型的细胞凋亡的形态学变化：细胞核固缩,染色质凝集,呈新月型紧贴于核膜周边,核碎裂,染色质片断化,凋 亡小体形成等。流式细胞仪ＤＮＡ直方图上出现典型的亚二倍体的“凋亡峰”。ＴＵＮＥＬ染色法     

Arsenic trioxide induces apoptosis of human gastrointestinal cancer cells

AIM:To investigate the changes in apoptosis in gastrointestinal cancer cells from patients with gastrointestinal cancers treated with arsenic trioxide(As2O3);and to study the possible molecular mechanisms of such changes by detecting the expression levels of p53and Bcl-2.METHODS:Twenty patients with gastrointestinal adenocarcinoma based on endoscopic and biopsy findings(ten patients with gastric cancer and ten patients with colorectal cancer)who received treatment in our hospital between August 2007 and December 2008were included in this study.None of the patients had received anti-tumour agents prior to As2O3 treatment.As2O3 was administered intravenously at a dose of 0.01g/d diluted with 5%glucose in normal saline for 2-3h for 3 consecutive days before surgery.Morphological changes associated with apoptosis of gastrointestinal cancer cells were observed by light microscopy.Changes in the apoptotic index induced by As2O3 were investigated using the terminal deoxynucleotidyl transferase dUTP nick end labelling method.Expression levels of p53 and Bcl-2 proteins in gastrointestinal cancer tissues were determined by immunohistochemistry.RESULTS:The apoptotic index of human gastrointestinal cancer cells was higher in cells from patients treated with As2O3 than in those not treated(P<0.05).p53 protein expression in gastrointestinal tissues was unchanged by As2O3(P>0.05).However,Bcl-2 protein expression in gastrointestinal tissues was downregulated by As2O3(P<0.01).CONCLUSION:These results demonstrate that As2O3treatment in patients with gastrointestinal cancers can induce apoptosis in gastrointestinal cancer cells and down-regulate Bcl-2 protein expression.     

三氧化二砷治疗晚期原发性肝癌的临床观察

目的探讨三氧化二砷(As2O3)治疗晚期原发性肝癌(PLC)的临床价值。方法将48例患者随机分为治疗组(26例)和对照组(22例)。两组患者在保肝、抗病毒、支持对症等治疗基础上,治疗组加用As2O3 10 mg,10%葡萄糖注射液500 ml,每日1次静脉输注,每2周为1个疗程,间隔2周进行下一个疗程,共2个疗程,观察结束复查并进行疗效评估。结果两组患者观察结束的客观有效率、获益率分别为0.0%、19.2%(P=0.0376)和22.8%、53.8%(P=0.0083),两组患者生活质量改善和稳定率分别为31.8%和65.4%(P=0.0291)。结论 As2O3治疗晚期PLC具有一定的临床价值,对于肝功能差且无法耐受其他治疗的PLC患者,As2O3仍不失是一种较有效的治疗手段。