肿瘤坏死因子家族及其相关药物的研究进展

细胞凋亡是进化保守的重要生物学过程,具有重要的生理和病理作用,如在免疫系统的发育与稳态以及多种疾病（包括肿瘤）的发 生、发展、预后及治疗等过程中起重要作用。因此,近年来参与细胞凋亡信号转导的肿瘤坏死因子（TNF）/TNF 受体（TNFR）家族的重要 成员TNFα/TNFR、Fas/FasL和TRAIL/TRAILR成为重要的药物靶点,并开发出多个相关靶向药物,尤其是生物药物,其中有些在临床疗 效和商业上获得巨大成功。简介参与细胞凋亡信号转导的TNF/TNFR家族重要成员,着重对其通过介导细胞凋亡而发挥的生物学作用及其 相关药物研发作一综述,希望对我国的药物研发有所裨益。     

Fas／FasL与消化道肿瘤的相关性

Fas,FasL均是细胞表面受体。正常情况下,Fas分子主要分布于人体各个组织器官及病变细胞表面,FasL广泛分布于活化的T细胞等免疫细胞表面。Fas与FasL的结合可导致表达Fas的细胞凋亡,平衡机体免疫反应。当机体发生肿瘤时,肿瘤细胞表面Fas表达下调,有时甚至出现FasL的表达,不但削弱了Fas阳性淋巴细胞的攻击能力,而且赋予了肿瘤细胞杀伤免疫细胞的能力,即肿瘤免疫逃逸的新机制—Fas反击。就这一新机制与消化道肿瘤尤其胃部肿瘤的相关性做一综述。     

Fas ligand在宫颈癌形成中的作用及机制研究进展

FasL(Fas ligand)是一种II型膜蛋白,属于肿瘤坏死因子家族,在体内参与诱导细胞凋亡,发挥一定生理作用。同时, FasL在许多肿瘤组织中高表达,在宫颈癌的发生发展、转移及侵袭中发挥重要作用,其具体作用机制涉及多条信号通路,包括参与肿瘤细胞的被动逃逸与主动攻击、维持机体炎症状态以及发出非凋亡信号促进肿瘤发生等。FasL高表达会导致不良的肿瘤预后,降低患者生存率。由于FasL可参与肿瘤细胞免疫逃逸,因此,针对FasL的靶向治疗可能为肿瘤基因治疗或免疫治疗提供一个新的方向。该文对FasL在宫颈癌发生发展中的作用机制及其在治疗方面的应用加以综述,从而为探索新的宫颈癌治疗靶点提供科学依据。     

TNF受体家族介导的细胞凋亡信号转导

肿瘤坏死因子（TNF）家族是一类多功能的细胞因子,具有诱导细胞凋亡、抗病毒、免疫调节等多种生物学活性.其中一些成员可以通过和细胞膜上相应受体（即TNF受体家族成员）结合,启动细胞内的凋亡机制,而诱导细胞凋亡.一些蛋白质（如TRADD、FADD、RIP、RAIDD等）参与这些信号传递过程.越来越多的TNF家族成员、TNF受体以及与细胞凋亡相关的Caspase蛋白酶家族成员被人们发现.     

Fas/FasL系统与类风湿关节炎发病机制的研究进展

类风湿关节炎是机体对自身滑膜发生免疫反应的疾病,其主要病理特征是滑膜增生和多种炎症细胞的浸润。滑膜增生的有关机制仍不清楚,目前认为可能是滑膜细胞和炎症浸润细胞数量增加及凋亡相对减少,即细胞凋亡程度不及增殖程度所致。Fas/FasL系统是细胞凋亡的重要途径之一,通过影响滑膜细胞的Fas/FasL表达可以诱导其凋亡。本文对Fas/FasL的性质、结构、功能、Fas/FasL与RA发病机制及RA治疗的关系进行综述。     

凋亡信号调节激酶1对细胞凋亡的调节作用

细胞存活与凋亡之间的平衡是多细胞生物正常发育与稳态的关键。细胞凋亡是受多种因素高度调控的细胞程序性死亡过程。凋亡信号调节激酶 1 (ASK1 )是促分裂原活化蛋白激酶激酶激酶家族的成员之一 ,它分别激活SER1 JNK和MKK3 MKK6 p38途径 ,在细胞因子及应激诱导细胞凋亡过程中起着关键作用。TNF受体和Fas信号转导系统在抗凋亡与促凋亡过程中发挥重要作用 ,其中包括TNF受体Ⅰ相关死亡域蛋白 (TRADD)、Fas相关死亡域蛋白 (FADD)等多种蛋白因子。细胞色素C是线粒体依赖性死亡信号 ,受Bcl 2家族蛋白的调节。反应性氧化合物的氧化激活使硫氧还蛋白 (Trx)氧化 ,并与ASK1分离 ,从而激活ASK1造成细胞凋亡。总之 ,许多促凋亡与抗凋亡因子组成复杂的、相互拮抗的机制。在信号转导的各种不同的关卡上 ,这些因子的平衡作用最终决定细胞的生与死。     

FasL在睾丸细胞的定位

FasL/Fas系统介导的胞外信号凋亡途径是哺乳动物睾丸生殖细胞凋亡的一条主要途径,然而,关于FasL在睾丸细胞中的定位却存在争议。本文对近年来国内外关于FasL在睾丸中的细胞定位研究进行了综述,为阐明FasL/Fas系统介导生殖细胞凋亡的机制提供资料,对深入理解睾丸中Sertoli细胞和生殖细胞间的调控关系及临床实践具有一定的指导作用。     

可溶性人TRAIL分子的制备及其抗肿瘤活性

TRAIL(TNF relatedapoptosis inducingligand)是1 995年发现的一个新的TNF超家族成员.使人感兴趣的是该分子既可广泛介导多种组织来源的肿瘤细胞发生凋亡而基本不影响正常细胞的功能,也可引起许多对于FasL和TNF α有抗性的细胞凋亡[1 ,2 ] .因此,有可能成为一种新的抗肿瘤药物.     

人脑星形细胞瘤中p53，Fas／FasL的表达及其与凋亡关系的研究

目的：探讨细胞凋亡在星形细胞瘤中的作用及其与p53、Fas和Fas配体（Fas ligand,FasL）的关系。方法：对43例星形细胞瘤的标本分别进行HE染色,TUNEL及免疫组化分别标记p53,Fas和FasL。结果：高级别肿瘤和低级别肿瘤间的凋亡无显著差异（P〉0．05）。高级别星形细胞瘤的p53,Fas和FasL的表达均显著高于低级别肿瘤（P均〈0．05）。结论：突变型p53可作为评价星形细胞瘤生物学行为的参考指标。与低级别星形细胞瘤相比,高级别肿瘤中的细胞凋亡受到了抑制,且Fas与FasL的过表达对细胞凋亡可产生明显影响。     

人脑星形细胞瘤中p53，Fas/FasL 的表达及其与凋亡关系的研究

目的:探讨细胞凋亡在星形细胞瘤中的作用及其与p53、Fas和Fas配体(Fas ligand,FasL)的关系。方法:对43例星形细胞瘤的标本分别进行HE染色,TUNEL及免疫组化分别标记p53,Fas和FasL。结果:高级别肿瘤和低级别肿瘤间的凋亡无显著差异(P>0.05)。高级别星形细胞瘤的p53,Fas和FasL的表达均显著高于低级别肿瘤(P均<0.05)。结论:突变型p53可作为评价星形细胞瘤生物学行为的参考指标。与低级别星形细胞瘤相比,高级别肿瘤中的细胞凋亡受到了抑制,且Fas与FasL的过表达对细胞凋亡可产生明显影响。     

Fas and Fas ligand in gut and liver

Apoptosis (programmed cell death) has been shown to play a major role in development and in the pathogenesis of numerous diseases. A principal mechanism of apoptosis is molecular interaction between surface molecules known as the "death receptors" and their ligands. Perhaps the best-studied death receptor and ligand system is the Fas/Fas ligand (FasL) system, in which FasL, a member of the tumor necrosis factor (TNF) family of death-inducing ligands, signals death through the death receptor Fas, thereby resulting in the apoptotic death of the cell. Numerous cells in the liver and gastrointestinal tract have been shown to express Fas/FasL, and there is a growing body of evidence that the Fas/FasL system plays a major role in the pathogenesis of many liver and gastrointestinal diseases, such as inflammatory bowel disease, graft vs. host disease, and hepatitis. Here we review the Fas/FasL system and the evidence that it is involved in the pathogenesis of liver and gastrointestinal diseases.     

Fas and Fas ligand mutations inhibit autoantibody production in pristane-induced lupus

Mutations of Fas (lpr) or Fas ligand (gld) cause a limited lupus-like syndrome in B6 mice by interfering with the deletion of autoreactive B and/or T cells. A more generalized lupus syndrome reminiscent of that of MRL mice can be induced in nonautoimmune strains by pristane, which causes a nonspecific inflammatory response in the peritoneal cavity. We hypothesized that, as in MRL mice, the lpr and gld mutations might accelerate lupus in pristane-treated mice. Pristane-treated B6 mice developed anti-nRNP/Sm, Su, and ribosomal P Abs, but little anti-ssDNA or chromatin. In contrast, B6/lpr and B6/gld mice spontaneously developed anti-ssDNA/chromatin Abs, but not anti-nRNP/Sm/Su/ribosomal P. Unexpectedly, B6/lpr and B6/gld mice were highly resistant to the induction by pristane of IgM anti-ssDNA (2 wk) and IgG anti-nRNP/Sm/Su/ribosomal P autoantibodies (6 mo), suggesting that intact Fas signaling is necessary. Interestingly, pristane did not enhance IgG chromatin Ab production in B6/lpr or B6/gld mice, suggesting that it did not influence the production of autoantibodies that develop spontaneously in the setting of Fas deficiency. Pristane treatment also decreased lymphoproliferation in B6/lpr mice. Increased production of IL-12 was associated consistently with the production of anti-nRNP/Sm/Su/ribosomal P as well as anti-DNA/chromatin. In contrast, production of anti-DNA/chromatin Abs was associated with IL-6 overproduction in pristane-treated mice, but not in lpr mice. The data strongly support the idea that different subsets of autoantibodies are regulated differentially by cytokine stimulation and/or Fas signaling.     

Immunohistochemical study on Fas and Fas ligand in skin wound healing

An immunohistochemical study on the expression of Fas and Fas ligand (Fas L) was performed in order to examine the role of apoptosis through Fas–Fas L in mouse skin wound healing. After a 1-cm-long incision in the central dorsum skin, mice were sacrificed at intervals ranging from 0.5 to 240h, followed by the sampling of wound margin. The expression of Fas and Fas L in the wound margins and in uninjured skin controls was studied using frozen sections. In uninjured skin controls, a very weak expression of Fas and Fas L was detected immunohistochemically in hair follicles, sebaceous glands and epidermal cells. In wounded specimens, polymorphonuclear cells and inflammatory mononuclear ones (round-shaped and spindle-shaped types) were evident. A single immunostaining showed that Fas or Fas L was detectable in inflammatory mononuclear cells involved in the skin wound healing process. Double immunostaining for Fas and Fas L revealed that inflammatory mononuclear cells co-expressed both antigens. In situ TUNEL combined with immunostaining showed that the inflammatory mononuclear cells expressing Fas or Fas L and the polymorphonuclear cells were TUNEL-stained, although neither Fas nor Fas L was detected in the polymorphonuclear cells. The number of TUNEL-positive, inflammatory mononuclear cells expressing Fas or Fas L per 0.01×0.01cm² was counted. The average number of 10 randomly selected microscope fields reached a peak at the fibro-proliferative phase of wound healing. These results indicate that apoptosis through Fas and Fas L may play an important role for reducing the cellularity during skin wound healing in mice.     

Expression of Fas/Fas ligand by decidual leukocytes in hydatidiform mole

Complete hydatidiform moles are entirely paternally derived and, therefore, represent a complete intrauterine allograft that might be expected to provoke an altered maternal immune response compared with that of normal pregnancy. Uterine decidua contains a large leukocyte population, of which 10%-20% are T lymphocytes. Fas ligand (FasL) expression by placental trophoblast may induce apoptosis of Fas+ lymphocytes, thereby facilitating immune tolerance and survival of the molar trophoblast. Our previous studies have shown an increase in activated CD4+ decidual T cells in molar pregnancy compared with normal pregnancy. This study was designed to characterize and quantitate Fas/FasL expression by decidual leukocytes in complete and partial hydatidiform mole compared with that in normal early pregnancy using single and double immunohistochemical labeling (i.e., avidin-biotin-peroxidase and avidin-biotin-alkaline phosphatase). A significant increase was found in Fas and FasL expression by decidual CD4+ T cells in complete (Fas+, P = 0.0106; FasL+, P = 0.0081) and partial (Fas+, P = 0.0131; FasL+, P = 0.0051) hydatidiform moles, as was a significant decrease in Fas expression by decidual CD8+ T cells in complete (P = 0.0137) and partial (P = 0.0202) hydatidiform mole compared with normal early pregnancy. The implications of altered Fas/FasL status of decidual T-cell subsets in hydatidiform mole are also discussed.     

Doxycycline induces Fas/Fas ligand-mediated apoptosis in Jurkat T lymphocytes.

Tetracyclines have been used in the treatment of chronic inflammatory diseases associated with local infiltration of inflammatory cells and matrix destruction as observed in rheumatoid arthritis and periodontal disease. Fas/Fas ligand (FasL)-mediated apoptosis plays an important role in maintaining T lymphocyte homeostasis and modulating immune response. The present study demonstrates that doxycycline inhibits Jurkat T lymphocyte proliferation and induces apoptosis. The phytohemagglutinin (PHA)-activated Jurkat cells are more susceptible to doxycycline-induced apoptosis. Furthermore, doxycycline-induced apoptosis is associated with increased Fas/FasL expression in Jurkat cells. The increase of apoptosis in Jurkat cells treated with doxycycline is consistent with the increase of FasL expression. These results suggest that doxycycline may downregulate the inflammatory process in certain diseases by eliminating activated T lymphocytes through Fas/FasL-mediated apoptosis.     

Expression of Fas antigen and Fas ligand in bronchoalveolar lavage from silicosis patients

OBJECTIVE: To understand the role of apoptosis through Fas/Fas ligand (FasL) interaction in the pathogenesis of silicosis, we examined the expression of Fas antigen, FasL and apoptosis in bronchoalveolar lavage fluid lymphocytes obtained from patients with silicosis. MATERIALS AND METHODS: Ten patients with silicosis, and 10 healthy controls were studied. Non-adherent cells were separated and analysed by cytometry for the expression of Fas antigen, FasL, and the co-expression of Fas/FasL. By double staining, we studied the FasL expression on CD4, CD8, CD56 and CD45RO-positive cells. DNA fragmentation was investigated by the terminal deoxy(d) UTP nick end labelling (TUNEL) method. RESULTS: We have found Fas and FasL expression in silicosis patients to be significantly higher than those in healthy controls. Interestingly, 6-18% of lymphocytes from silicosis patients co-expressed Fas and FasL. In silicosis patients, FasL was highly expressed on CD4+, CD56+ and CD45RO+ bronchoalveolar lavage cells. Fas antigen expressing cells showed DNA fragmentation characteristic for apoptosis. CONCLUSION: FasL was significantly expressed on cytotoxic effector and memory cells. The Fas/FasL system is implicated in the inflammatory process observed in silicosis patients.     

The critical role of protein kinase C-theta in Fas/Fas ligand-mediated apoptosis

A functional immune system not only requires rapid expansion of antigenic specific T cells, but also requires efficient deletion of clonally expanded T cells to avoid accumulation of T cells. Fas/Fas ligand (FasL)-mediated apoptosis plays a critical role in the deletion of activated peripheral T cells, which is clearly demonstrated by superantigen-induced expansion and subsequent deletion of T cells. In this study, we show that in the absence of protein kinase C-theta (PKC-theta), superantigen (staphylococcal enterotoxin B)-induced deletion of Vbeta8(+) CD4(+) T cells was defective in PKC-theta(-/-) mice. In response to staphylococcal enterotoxin B challenge, up-regulation of FasL, but not Fas, was significantly reduced in PKC-theta(-/-) mice. PKC-theta is thus required for maximum up-regulation of FasL in vivo. We further show that stimulation of FasL expression depends on PKC-theta-mediated activation of NF-AT pathway. In addition, PKC-theta(-/-) T cells displayed resistance to Fas-mediated apoptosis as well as activation-induced cell death (AICD). In the absence of PKC-theta, Fas-induced activation of apoptotic molecules such as caspase-8, caspase-3, and Bid was not efficient. However, AICD as well as Fas-mediated apoptosis of PKC-theta(-/-) T cells were restored in the presence of high concentration of IL-2, a critical factor required for potentiating T cells for AICD. PKC-theta is thus required for promoting FasL expression and for potentiating Fas-mediated apoptosis.     

Serum Levels of Soluble Fas and Fas Ligand in Iranian Women with Pre-eclampsia

Background:The precise responsible mechanism of pre-eclampsia remains controversial however, recent data suggest a main role of the abnormal activation of the adaptive immune system and Apoptosis. In this study, we have measured serum levels of Fas/Fasl as two important members of extrinsic apoptotic pathway in patient with pre-eclampsia.Methods:207 participants including 99 pre-eclampsia patients and 108 age and sex-matched normal pregnant women were involved in the case-control study. Plasma sample from each participant was collected and stored at –20 °C until batch processing.Serum levels of Fas and Fas ligand were measured by ELISA for each participant including 99 pre-eclampsia patients and 108 normal pregnant women. Following a test of statistical normality, nonparametric data were analyzed by Mann-Whitney.Results:sFas levels in case group was significantly higher than controls; 584 (397-892) pg/ml in cases opposed to 341 (213-602) pg/ml in controls (p value< 0.01). sFasL in pre-eclampsia women was a little lower than controls; 255 (173-318) pg/ml and in case group compared to 265.5 (184-381.5) pg/ml in controls.Conclusion:We have found the increased levels of sFas in patients with pre-eclampsia in compare with the healthy pregnant women. It seems that abnormality in sFAS is related with pre-eclampsia.Key Words: Pre-eclampsia, Pregnancy, sFAS, sFASL, Apoptosis     

Non-apoptotic Fas signaling

Fas (Apo-1, CD95) and Fas-Ligand (FasL, CD95L) are typical members of the TNF receptor and TNF ligand family, respectively, with a pivotal role in the regulation of apoptotic processes, including activation-induced cell death, T-cell-induced cytotoxicity, immune privilege and tumor surveillance. Impairment of the FasL/Fas system has been implicated in liver failure, autoimmune diseases and immune deficiency. Thus, the FasL/Fas system was mainly appreciated with respect to its death-inducing capabilities. However, there is increasing evidence that activation of Fas can also result in non-apoptotic responses like cell proliferation or NF-kappaB activation. While the apoptotic features of the FasL/Fas system and the pathways involved are comparably well investigated, the pathways that are utilized by Fas to transduce proliferative and activating signals are poorly understood. This review is focused on the non-apoptotic functions of the FasL/Fas system. In particular, the similarities and differences of the molecular mechanisms of apoptotic and non-apoptotic Fas signaling are addressed.