p53 基因相关的细胞非经典死亡

[摘要] 程序性细胞死亡是多细胞生物死亡的重要生物学过程,其调控方式复杂,对维持细胞内环境稳定十分重要。在过去的几年中,除了凋亡之外,对程序性细胞死亡的非凋亡形式的研究也取得了进展。p53 作为经典的肿瘤抑制因子,除了控制细胞增殖和凋亡外,也参与非典型细胞死亡调控。p53 通过对其下游靶点的转录调控以及与关键蛋白的直接作用,直接或间接调节细胞的非典型死亡。本文对p53 在凋亡、铁中毒、细胞程序性坏死、自噬性细胞死亡、有丝分裂灾难、副凋亡等几种非典型细胞死亡模式中的作用作一综述,为肿瘤抑制机制的阐明及癌症药物研制提供相应参考。     

细胞凋亡与肝癌研究进展

细胞增殖、分化和死亡是多细胞个体发育过程中三项最基本的生命活动,三者都以保证个体的整体生存和生命活动的正常进行为目标,其中任一过程发生异常都会引起机体病变.近年来,细胞死亡与疾病的关系逐渐得到人们的关注和重视.业已发现,恶性肿瘤的发生、发展不仅是细胞增殖失控、分化失调的结果,细胞死亡的异常在其中也起着重要作用.细胞死亡有坏死(necrosis)与凋亡(apoptosis)二种不同的基本形式.目前对细胞凋亡的研究已有较大进展,为探索恶性肿瘤的防治方法提供了一个崭新的思路.1 细胞凋亡的概念细胞凋亡于1972年由Kerr等首次提出.机体正常生长发育过程中的细胞死亡称为程序性细胞死亡(programmedcell death,PCD),指细胞在一定条件下,受自身基因调控,自行结束生命活动的过程.术语PCD强调的是这一过程机制     

γ线引起小鼠骨髓造血细胞凋亡的定量病理研究

迄今，骨髓辐射损伤后造血细胞凋亡的病理研究很少，其定量变化规律更未见报道。本文采用６０Ｃｏγ射线照射ＬＡＣＡ小鼠，于照射后６小时、１天及３天分批活杀，将右股骨骨髓经３％戊二醛及１％锇酸固定，制作半薄切片、超薄切片，并用ＣａｍｂｒｉｄｇｅＱｕａｎｔｉｍｅｔ９７０型图像分析仪，定量研究了辐射诱导的骨髓造血细胞凋亡的形态特征及其与照射剂量之间的关系。结果表明：对照组动物骨髓仅有少数造血细胞凋亡，而照射后６小时各剂量组动物骨髓内发生凋亡的造血细胞均明显增多，病理特点为：凋亡早期见核染色质浓缩、边移，呈半月形、环形或不规则形；中期见大小不等，形状不一的染色质团块周围有核膜包绕，核碎片形成；晚期见凋亡小体形成，可游离于细胞间或被邻近细胞吞噬。定量分析示各照射组动物凋亡的骨髓造血细胞的数密度和面密度均明显增加，与对照组比，其差异显著（Ｐ＜００１）。且剂量越大，凋亡细胞的数密度和面密度越大。最后，本文作者根据实验结果指出：凋亡是辐射介导的骨髓造血细胞死亡的主要死亡方式。本研究为急性放射病的诊治提供直接依据，亦可能对其他原因引起的细胞凋亡的研究具有参考意义。     

PDCD5与肿瘤的临床相关性

程序性细胞死亡因子5（PDCD5）是一种新的程序性细胞死亡调控基因。PDCD5表达广泛,进化保守,具有促进肺癌、肝癌等多种肿瘤细胞凋亡和抑制细胞增殖的效应。PDCD5在疾病情况下,特别是在肿瘤细胞中的表达明显下调,与肿瘤有着密不可分的临床相关性,对肿瘤的发现、诊断和治疗有很大的临床检验价值。     

高温联合顺铂及多西他赛对肺腺癌A549细胞体外作用的研究

目的:研究高温联合顺铂(DDP)及多西他赛(TXT)对肺腺癌细胞株A549的体外作用.方法:不同处理因素作用于A549细胞后,应用四氮唑盐比色法(MTT法)测定细胞增殖情况,根据Veleriote法判断高温联合化疗药的作用效果;通过两药相互作用指数判断药物联合作用效果;流式细胞仪检测不同处理后细胞凋亡情况;光学显微镜及荧光显微镜观察细胞形态学变化.结果:高温和化疗药单独作用均对A549有生长抑制作用(P＜0.05);化疗药有剂量依赖关系;高温有温度依赖关系;高温与药物联合对细胞生长抑制作用强于单独高温组或单独化疗组(P＜0.01);DDP与高温联合为协同作用;TXT与高温联合为次加作用;DDP和TXT联合作用对细胞生长抑制为协同作用;42℃、DDP 2 μg/ml 和TXT 1μg/ml三者联合凋亡率明显高于其他处理组(P＜0.01);普通光镜和荧光显微镜下42℃、DDP 2 μg/ml 和TXT 1μg/ml三者联合凋亡细胞数较对照组和42℃组明显增多,细胞形态学变化明显.结论:DDP、TXT、高温三者体外联合作用对A549有明显的生长抑制和诱导凋亡作用.     

细胞程序性死亡与肿瘤的发生及治疗

细胞程序性死亡与肿瘤的发生及治疗张明综述生物体内细胞死亡有两种方式：坏死与程序性细胞死亡。坏死是由各种有害条件和有毒物质所引起的细胞病理性死亡过程。程序性细胞死亡（Ｐｒｏ－ｇｒａｍｍｅｄＣｅｌＤｅａｔｈ）也称凋亡（Ａ－ｐｏｐｔｏｓｉｓ），它不同于坏死...     

凋亡相关因子与卵巢肿瘤研究进展

细胞凋亡又称程序性细胞死亡,其在卵巢肿瘤中起着举足轻重的作用.研究发现,凋亡相关因子的调控失衡直接导致卵巢肿瘤的发生发展,影响肿瘤的预后和治疗.现详述几类重要的凋亡相关因子与卵巢肿瘤的最新研究动态.     

肿瘤抑制基因p53与自噬

近年来研究表明,p53是一种抑癌基因,作为一种重要的转录因子,其在细胞周期阻滞、凋亡中都发挥着重要作用。自噬是在细胞营养物质匮乏条件下蛋白质动态降解的过程,自噬性细胞死亡是不同于细胞凋亡的另一种细胞程序性死亡模式,被称之为II型程序性死亡,细胞凋亡为I型程序性死亡。研究表明,肿瘤的发生发展与自噬性细胞死亡相关,作为肿瘤抑制基因p53也参与了自噬活性的调节。本文对此做一简要概述。     

自噬性细胞死亡研究进展

自噬性细胞死亡（autophagic cell death）为Ⅱ型程序性细胞死亡,同细胞凋亡（Ⅰ型程序性细胞死亡）一样被发现多年,但近些年才引起人们的关注。现已证实自噬性细胞死亡是除细胞凋亡外另一重要的死亡调控机制。自噬性细胞死亡在参与细胞存活、分化、增殖和衰老的同时还可能参与多种疾病的发生发展,尤其与肿瘤及其电离辐射的关系越来越密切,因此研究自噬发生及调控的分子机制对于进一步了解自噬与疾病的关系,探索临床治疗方案具有重要的意义。本文就近些年自噬性细胞死亡的研究进展作一详细综述。     

肿瘤抑制基因p53与自噬

近年来研究表明,p53是一种抑癌基因,作为一种重要的转录因子,其在细胞周期阻滞、凋亡中都发挥着重要作用。自噬是在细胞营养物质匮乏条件下蛋白质动态降解的过程,自噬性细胞死亡是不同于细胞凋亡的另一种细胞程序性死亡模式,被称之为II型程序性死亡,细胞凋亡为I型程序性死亡。研究表明,肿瘤的发生发展与自噬性细胞死亡相关,作为肿瘤抑制基因p53也参与了自噬活性的调节。本文对此做一简要概述。     

雷公藤内酯醇联合热疗对 MKN28 细胞增殖抑制作用的研究简

目的：研究雷公藤内酯醇（triptolid,TPL）与热疗联合应用对胃癌细胞MKN28增殖、细胞周期分布及磷酸化蛋白激酶B（phosphorylation of Akt,p-Akt）表达的影响。方法：将体外复苏和培养的胃癌细胞系MKN28分为四个组：对照组、TPL组、热疗组、TPL联合热疗组。其中TPL刺激浓度为20ng/ml,热疗采用43℃下加热150min。使用四甲基偶氮唑盐比色法（measurement of trititaed thymidine incorporation,MTT）检测细胞增殖并计算细胞增殖抑制率。流式细胞仪（flow cytometer,FCM）检测细胞周期分布的变化,使用蛋白质印迹法（Western blot）检测p-Akt水平。结果：热疗组,TPL组和TPL联合热疗组MKN28 细胞增殖抑制率分别为21.2%,28.5%和54.5%,联合组显著高于TPL组和热疗组。FCM结果显示热疗组G0/G1期减少至（62.7±3.8）%,G2/M期增多至（18.1±3.2）%。TPL组G0/G1期增多至（80.62±4.6）%,G2/M期增多至（16.18±2.2）%。联合组G0/G1期（77.72±8.1）%,G2/M期增多至（19.62±2.4）%。热疗组和TPL组对细胞周期的影响不一样。与热疗组和TPL组相比,联合组G2/M期增多最明显。Western blot检测各组p-Akt蛋白表达均有降低,其中对照组（1.81±0.05）,热疗组（1.28±0.01）,TPL组（0.95±0.07）,联合组（0.58±0.06）,联合组下降最明显（P＜0.05）。结论：TPL联合热疗对MKN28细胞增殖抑制作用更强,可能与二者对细胞周期的作用点不同,并能同时降低细胞内p-Akt的表达有关。     

c-Myc induction of programmed cell death may contribute to carcinogenesis: a perspective inspired by several concepts of chemical carcinogenesis

The c-Myc protein, encoded by c-myc gene, in its wild-type form can induce tumors with a high frequency and can induce massive programmed cell death (PCD) in most transgenic mouse models, with greater efficiency than other oncogenes. Evidence also indicates that c-Myc can cause proliferative inhibition, i.e. mitoinhibition. The c-Myc-induced PCD and mitoinhibition, which may be attributable to its inhibition of cyclin D1 and induction of p53, may impose a pressure of compensatory proliferation, i.e. regeneration, onto the initiated cells (cancer progenitor cells) that occur sporadically and are resistant to the mitoinhibition. The initiated cells can thus proliferate robustly and progress to a malignancy. This hypothetical thinking, i.e. the concurrent PCD and mitoinhibition induced by c-Myc can promote carcinogenesis, predicts that an optimal balance is achieved between cell death and ensuing regeneration during oncogenic transformation by c-Myc, which can better promote carcinogenesis. In this perspective, we summarize accumulating evidence and challenge the current model that oncoprotein induces carcinogenesis by promoting cellular proliferation and/or inhibiting PCD. Inspired by c-myc oncogene, we surmise that many tumor-suppressive or growth-inhibitory genes may also be able to promote carcinogenesis in a similar way, i.e. by inducing PCD and/or mitoinhibition of normal cells to create a need for compensatory proliferation that drives a robust replication of initiating cells.     

Antisense bcl-2 treatment increases programmed cell death in non-small cell lung cancer cell lines

Programmed cell death (PCD) is a genetically regulated pathway that is altered in many cancers. This process is, in part, regulated by the ratio of PCD inducers (Bax) or inhibitors (Bcl-2). An abnormally high ratio of Bcl-2 to Bax prevents PCD, thus contributing to resistance to chemotherapeutic agents, many of which are capable of inducing PCD. Non-small cell lung cancer (NSCLC) cells demonstrate resistance to these PCD-inducing agents. If Bcl-2 prevents NSCLC cells from entering the PCD pathway, then reducing the amount of endogenous Bcl-2 product may allow these cells to spontaneously enter the PCD pathway. Our purpose was to determine the effects of bcl-2 antisense treatment on the levels of programmed cell death in NSCLC cells. First, we determined whether bcl-2 and bax mRNA were expressed in three morphologically distinct NSCLC cell lines: NCI-H226 (squamous), NCI-H358 (adenocarcinoma), and NCI-H596 (adenosquamous). Cells were then exposed to synthetic antisense bcl-2 oligonucleotide treatment, after which programmed cell death was determined, as evidenced by DNA fragmentation. Bcl-2 protein expression was detected immunohistochemically. All three NSCLC cell lines expressed both bcl-2 and bax mRNA and had functional PCD pathways. Synthetic antisense bcl-2 oligonucleotide treatment resulted in decreased Bcl-2 levels, reduced cell proliferation, decreased cell viability, and increased levels of spontaneous PCD. This represents the first evidence that decreasing Bcl-2 in three morphologically distinct NSCLC cell lines allows the cells to spontaneously enter a PCD pathway. It also indicates the potential therapeutic use of antisense bcl-2 in the treatment of NSCLC.     

自噬与凋亡的相互关系在肿瘤方面的研究进展

肿瘤是一类涉及基因、代谢和信号传导异常等多方面因素引起的疾病,其发生的分子机制相当复杂,但本质上仍与细胞增殖与死亡的动态失衡有关。程序性细胞死亡（programmed cell death,PCD）是由基因控制的自杀程序引起的主动性死亡,对于多细胞生物个体发育的正常进行,维持内环境稳态以及抵御外界各种干扰因素方面有着关键性的意义。I型PCD（经典细胞凋亡）和II型PCD（自噬性细胞死亡）调控着肿瘤细胞的增殖与消耗,与肿瘤的发生、发展密切相关。本文结合近年来国内外研究进展,重点就自噬在肿瘤中的作用以及与凋亡的相互关系作一综述。     

Molecular Mechanisms of Apoptosis and Roles in Cancer Development and Treatment

Programmed cell death (PCD) or apoptosis is a mechanism which is crucial for all multicellular organisms tocontrol cell proliferation and maintain tissue homeostasis as well as eliminate harmful or unnecessary cells froman organism. Defects in the physiological mechanisms of apoptosis may contribute to different human diseases likecancer. Identification of the mechanisms of apoptosis and its effector proteins as well as the genes responsible forapoptosis has provided a new opportunity to discover and develop novel agents that can increase the sensitivity ofcancer cells to undergo apoptosis or reset their apoptotic threshold. These novel targeted therapies include thosetargeting anti-apoptotic Bcl-2 family members, p53, the extrinsic pathway, FLICE-inhibitory protein (c-FLIP),inhibitor of apoptosis (IAP) proteins, and the caspases. In recent years a number of these novel agents havebeen assessed in preclinical and clinical trials. In this review, we introduce some of the key regulatory moleculesthat control the apoptotic pathways, extrinsic and intrinsic death receptors, discuss how defects in apoptoticpathways contribute to cancer, and list several agents being developed to target apoptosis.     

热疗联合紫杉醇对人舌鳞癌细胞系CAL-27增殖、凋亡和周期影响

目的:观察热疗联合紫杉醇对人舌鳞癌细胞系CAL-27增殖、凋亡和周期的影响并探讨其机制。方法:CCK-8法确定紫杉醇工作浓度,将体外培养CAL-27细胞分为对照组、紫杉醇组、42℃热疗组和联合治疗组。克隆形成实验检测细胞增殖能力,流式细胞术检测细胞周期及凋亡,蛋白印迹法检测AKT、p-AKT、Bcl-2、Bax蛋白表达...     

Beclin-1-independent autophagy mediates programmed cancer cell death through interplays with endoplasmic reticulum and/or mitochondria in colbat chloride-induced hypoxia

Autophagy has dual functions in cell survival and death. However, the effects of autophagy on cancer cell survival or death remain controversial. In this study, we show that Autophagy can mediate programmed cell death (PCD) of cancer cells in responding to cobalt chloride (CoCl₂)-induced hypoxia in a Beclin-1-independent but autophagy protein 5 (ATG5)-dependent manner. Although ATG5 is not directly induced by CoCl₂, its constitutive expression is essential for CoCl₂-induced PCD. The ATG5-mediated autophagic PCD requires interplays with endoplasmic reticulum (ER) and/or mitochondria. In this process, ATG5 plays a central role in regulating ER stress protein CCAAT/enhancer-binding protein (C/EBP) homologous protein (CHOP) and mitochondrial protein second mitochondria derived activator of caspases (Smac). Two pathways for autophagic PCD in cancer cells responding to hypoxia have been identified: ATG5/CHOP/Smac pathway and ATG5/Smac pathway, which are probably dependent on the context of cell lines. The former is more potent than the latter for the induction of PCD at the early stage of hypoxia, although the ultimate efficiency of both pathways is comparable. In addition, both pathways may require ATG5-mediated conversion of LC3-I into LC3-II. Therefore, we have defined two autophagy-mediated pathways for the PCD of cancer cells in hypoxia, which are dependent on ATG5, interplayed with ER and mitochondria and tightly regulated by hypoxic status. The findings provide a new evidence that autophagy may inhibit tumor cell proliferation through trigger of PCD, facilitating the development of novel anti-cancer drugs.     

热疗联合紫杉醇对卵巢癌A2780细胞增殖、侵袭及AKT磷酸化的影响

目的:探讨热疗联合紫杉醇（Paclitaxel）对卵巢癌A2780细胞增殖、侵袭及AKT磷酸化的影响。方法:将A2780细胞分为4组:热疗组(41℃加热90min)、紫杉醇组、热疗联合紫杉醇组及对照组(常规培养细胞)。用MTT法检测细胞增殖情况,测定紫杉醇联合热疗对A2780细胞体外增殖抑制的影响;Transwell侵袭实验检测细胞的侵袭能力的变化,测定紫杉醇联合热疗对A2780细胞体外侵袭能力的影响;Western blot检测各组细胞中AKT磷酸化的变化。结果:热疗联合紫杉醇组细胞增殖率与其他各组比较均明显降低,差异有统计学意义（P＜0.05）;热疗联合紫杉醇组细胞的侵袭能力同样明显减弱,差异有统计学意义（P＜0.05）;同时,热疗联合紫杉醇组细胞中AKT磷酸化水平与其他各组相比亦显著降低,差异有统计学意义（P＜0.05）。结论:热疗联合紫杉醇可通过降低A2780细胞中AKT的磷酸化水平从而明显抑制细胞的增殖及侵袭能力。     

Programmed cell death: the influence of CD40, CD95 (Fas or Apo-I) and their ligands

Programmed cell death (PCD) or apoptosis is a process whereby developmental or environmental stimuli activate a specific series of events that culminate in cell death. PCD is essential for normal development and abnormality in the process can lead to defects ranging from embryonic lethality and tissue-specific perturbation of postnatal development to a high susceptibility to malignancy. Therapeutics that modulate the regulation of PCD may provide a new opportunity for the treatment of the PCD related diseases and cancer. CD40 and CD95 (Fas/Apo-I) are transmembrane proteins of the nerve growth factor/tumour necrosis factor α receptor superfamily. The death signal of PCD occurs when the CD95 receptor on the cell surface binds to the CD95 ligand (CD95L) or to the anti-CD95 monoclonal antibody (mAb). In contrast, PCD could be inhibited by the survival signal mediated from the binding of the CD40 receptor to the CD40 ligand (CD40L) or to the anti-CD40 mAb. In this review, the interaction of CD40/CD40L and CD95/CD95L on PCD in normal and malignant cells is discussed.     

Induction of macroautophagy in human colon cancer cells by soybean B-group triterpenoid saponins

The impact of triterpenoid saponins isolated from soybeans on suppression of colon cancer cell proliferation was evaluated. Experiments were conducted to determine the effects of a purified soybean B-group saponin extract on cell proliferation, cell-cycle distribution and programmed cell death in cultures of human HCT-15 colon adenocarcinoma cells. Treatment of cells with the soyasaponins at concentrations of 25-500 p.p.m. significantly reduced viable cell numbers after 24 and 48 h of exposure. Treatment of cells with 25 and 100 p.p.m. of saponins also resulted in a transient accumulation of cells in the S-phase of the cell cycle that was associated with a significant reduction of cyclin-dependant kinase-2 (CDK-2) activity. More striking was that, when examined by transmission electron microscopy, soyasaponin-treated cells exhibited an approximately 4.5-fold increase in cell morphologies characteristic of Type II non-apoptotic programmed cell death (PCD) including numerous autophagic vacuoles, changes that collectively suggest autophagic cell death. In addition, the protein levels of microtubule-associated protein light chain 3 (LC-3), a specific marker of macroautophagy, increased substantially following soyasaponin treatment. Taken together these results thus indicate that soybean saponins, at physiologically relevant doses, can suppress HCT-15 colon cancer cell proliferation through S-phase cell-cycle delay, and can induce macroautophagy, the hallmark of Type II PCD. These findings suggest that B-group soyasaponins may be another colon-cancer suppressive component of soy that warrants further examination as a potential chemopreventive phytochemical.