Synergism of Fas-mediated apoptosis and tumor necrosis factor on adriamycin cytotoxicity to transitional cell carcinoma

OBJECTIVE: To explore the accurate Fas antigenic expression in transitional cell carcinoma (TCC) cells and and compare its synergistic modulation on adriamycin cytotoxicity with alpha-tumor necrosis factor (TNF-alpha). METHODS: The expression of Fas antigen in normal urothelium and TCC cell lines was measured by flow cytometry. The Fas/Fas ligand reaction-induced cytotoxic changes in tumor cells were evaluated by microculture MTT technique. The synergism efficacy of Fas-mediated apoptosis and TNF-alpha on adriamycin cytotoxicity of TCC cells was analyzed. The Fas/Fas ligand-induced apoptosis in tumor cells was studied by annexin-V apoptotic cell expression and DNA ladder fragmentation analysis. RESULTS: 75% of TCC cell lines showed Fas antigen expression. The Fas expression was not influenced by in vitro growth density of tumor cells. Apoptosis of TCC cells was observed during 48 h of treatment after activation of the Fas/Fas ligand pathway. TNF-alpha had a higher cytotoxicity activity on TCC cells than Fas ligand (17 vs. 0.7%) while combination of both reagents had 30% increased synergistic cytotoxicity. The increasing rate of apoptotic body after 3 days of treatment was 74% in adriamycin, 32% in Fas ligand, 60% in TNF-alpha, 69% in Fas and adriamycin combination and Fas and TNF-alpha combination, 103% in combination of TNF-alpha and adriamycin, and 136% in combination of these three reagents individually. In the DNA ladder analysis, Fas ligand had a 1.5-fold increase of DNA fragmentation when compared with adriamycin while TNF-alpha had a 4.4-fold increase and triple combination had a 5.5-fold increase after 3 days of treatment. CONCLUSIONS: Although the Fas antigen expression is common in TCC cells and apoptosis can be activated by the Fas/Fas ligand pathway activation, the synergistic cytotoxicity of adriamycin by the Fas/Fas ligand pathway is lower than that of TNF-alpha.     

Fas配体在膀胱癌中的表达及意义

探讨肿瘤免疫逃避与膀胱发生、侵袭及复发的关系。方法采用ＳＡＢＣ免疫组化法检测１４例膀胱腺癌,３４例移行细胞癌及１０例慢性单纯性膀胱炎石蜡切片中Ｆａｓ配体的表达情况。结果ＳＣＣ中ＦａｓＬ无表达;ＡＣ８例表达、ＴＣＣ２０例明显表达且与组织类型无关;ＦａｓＬ的表达与临床分期及复发密切相关,而与ＴＣＣ的病理分级关系不密切。     

A non-cleavable mutant of Fas ligand does not prevent neutrophilic destruction of islet transplants

BACKGROUND: Fas ligand (FasL) mediates apoptosis of susceptible Fas-expressing lymphocytes, and may contribute to the maintenance of peripheral tolerance. In transplantation models, however, artificial expression of FasL on cellular as well as islet transplants results in accelerated rejection by neutrophils. The mechanism of the neutrophilic response to FasL expression is unknown. FasL, like other members of the tumor necrosis factor family, is cleaved to a soluble form by metalloproteases. We tested the hypothesis that soluble FasL (sFasL) was responsible for neutrophil migration by creating a non-cleavable mutant of FasL. METHODS: Three mutants of FasL with serial deletions in the putative proteolytic cleavage site of human FasL were made using inverse polymerase chain reaction. The relative fractions of sFasL and membrane-bound FasL were assessed by Western blot and immunoprecipitation, as well as by cytotoxicity assay using Fas-expressing target cells. The fully non-cleavable mutant was transduced into murine islets as well as myoblasts and tumor cell lines, and tested in a murine transplantation model. RESULTS: Serial deletions in the putative metalloprotease site of FasL resulted in a fully non-cleavable mutant of FasL (ncFasL). Expression of ncFasL in tumor lines induced higher levels of apoptosis in Fas bearing targets than wild-type FasL. Transplantation of ncFasL-expressing islets under the kidney capsule of allogenic mice resulted in accelerated rejection identical to that seen with wild-type Fas ligand-expressing islets. Myoblasts and tumor cell lines expressing ncFasL also induced neutrophil infiltration. CONCLUSIONS: Membrane-bound Fas ligand is fully capable of inducing a neutrophilic response to transplants, suggesting an activation by Fas ligand of neutrophil chemotactic factors.     

睾丸支持细胞免疫豁免功能的机理研究

目的:探讨睾丸支持细胞免疫功能发生的机制.方法:分离培养48h后的睾丸支持细胞与活化的淋巴细胞共同培养,MTT法检测其对淋巴细胞的杀伤作用;应用Fas IgG抗体阻断试验评价睾丸支持细胞杀伤活化的淋巴与Fas/FasL系统之间的关系.结果:睾丸支持细胞体外可杀伤活化的淋巴细胞,该种杀伤作用可以被抗Fas IgG抗体阻断,表明睾丸支持细胞通过Fas/FasL系统发挥其免疫豁免功能.结论:睾丸支持细胞能通过Fas/FasL作用而调节T细胞的活性,这可能是睾丸支持细胞提供局部免疫功能的机制之一.     

Expression of fas ligand on bile ductule epithelium in biliary atresia--a poor prognostic factor

PURPOSE: The aim of this study was to investigate the possible role of Fas and Fas ligand system in biliary atresia. METHODS: Immunohistochemical stains of Fas and Fas ligand (FasL) and in situ hybridization of Fas ligand messenger RNA (mRNA) were performed on paraffin-embedded liver specimens of 36 biliary atresia, 6 choledochal cysts, and 14 nontumorous parts of pediatric liver tumors. Apoptosis was detected by terminal deoxynucleotidyl transferase deoxy-UTP nick end labeling (TUNEL). The grade of liver fibrosis and results of bile drainage on the patients with biliary atresia were compared with the results of FasL expression. RESULTS: Fas protein was positive on the hepatocytes and bile ductule epithelia of all the livers examined and also positive on some monocytes around the portal area in all the biliary atresia patients. FasL protein was positive on bile ductule epithelia in 10 biliary atresia patients and also positive on some monocytes in most of the biliary atresia patients. Positive signals of FasL mRNA were noted on hepatocytes in 4 biliary atresia, bile ductule epithelia in 19 biliary atresia patients, and some monocytes in most of the biliary atresia patients. Apoptotic nuclei were present among monocytes in all the biliary atresia livers but present among bile ductule epithelia only on the BA with positive FasL mRNA signals on ductule epithelium. The fibrosis grade was similar between biliary atresia with positive FasL mRNA signals and negative signals. The bile drainage was better in the biliary atresia without positive FasL mRNA signals. CONCLUSIONS: Fas ligand expression on bile ductule epithelia in biliary atresia may be induced to counterattack the infiltrating lymphocytes. Although the factors for post-Kasai bile drainage are multiple, the authors suggest Fas ligand expression on bile ductule epithelia may be a poor prognostic factor by playing a role in the continuous damage and obliteration of intrahepatic bile ducts after Kasai operation.     

The evaluation of Fas/Fas ligand system in renal cell carcinoma--the effect of preoperative interferon-alpha therapy

OBJECTIVES: In order to investigate the effect of preoperative interferon (IFN)-alpha on Fas/Fas ligand (FasL) system, we examined Fas and FasL expression and the occurrence of apoptotic cell death in a preoperative therapy group, and in a control group using surgically resected renal cell carcinoma (RCC) tissues. METHODS: Ten cases were served as the preoperative therapy group, and sixteen cases as the control group. IFN-alpha was administered at five megaunits daily intramuscularly for two weeks in the preoperative therapy group. Immunohistochemistry for Fas and FasL, and terminal-deoxynucleotidyl-transferase (TdT)-mediated digoxigenin-dUTP nick end-labeling (TUNEL) were employed. We defined the labeling index (LI) as percentage of Fas- or FasL-positive cells in carcinomatous cells, and apoptotic index (AI) as percentage of TUNEL-positive cells in carcinomatous cells. RESULTS: Significant correlations were found between the LIs of Fas and AIs in all 26 cases. LIs of Fas and AIs of the preoperative therapy group were significantly higher than those of the control group. FasL expression was detected in nine out of ten cases in the preoperative therapy group, and in fourteen out of sixteen cases in the control group. There were no significant differences in LIs of FasL between two groups. CONCLUSION: These data suggest that apoptosis via the Fas/FasL system is functional, and that preoperative IFN-alpha treatment may up-regulate the Fas/FasL system in RCC. On the other hand, we need to investigate about an immune-escape mechanism through the FasL expression considering the relatively frequent expression of FasL in our results in RCC from now.     

Proapoptotic Fas ligand is expressed by normal kidney tubular epithelium and injured glomeruli

Fas ligand (FasL) is a cell membrane cytokine that can promote apoptosis through activation of Fas receptors. Fas receptor activation induces glomerular cell apoptosis in vivo and participates in tubular cell death during acute renal failure. However, there is little information on the expression of FasL in the kidney. This study reports that FasL mRNA and protein are present in normal mouse and rat kidney. In situ hybridization and immunohistochemistry showed that proximal tubular epithelium is the main site of FasL expression in the normal kidney. In addition, increased total kidney FasL mRNA and de novo FasL protein expression by glomerular cells were observed in two different models of glomerular injury : rat immune-complex proliferative glumerulonephritis and murine lupus nephritis. Both full-length and soluble FasL were increased in the kidneys of the mice with nephritis. Cultured murine proximal tubular epithelial MCT cells and primary cultures of murine tubular epithelial cells expressed FasL mRNA and protein. Tubular epithelium-derived FasL induced apoptosis in Fassensitive lymphoid cell lines but not in Fas-resistant lymphoid cell lines. By contrast, MCT cells grown in the presence of the survival factors of serum were resistant to FasL, and only became partially sensitive to apoptosis induced by high concentrations (100 ng/ml) of FasL upon serum deprivation. However, MCT cells stimulated with inflammatory mediators (tumor necrosis factor-alpha, interferon-gamma, and lipopolysaccharide) increased cell surface Fas expression and were sensitized to apoptosis induced by FasL (FasL 55 +/- 5% versus control 8.3 +/- 4.1% apoptotic cells at 24 h, P < 0.05). Cytokine-primed primary cultures of tubular epithelial cells also acquired sensitivity to FasL-induced apoptosis. These results suggest that FasL expression by intrinsic renal cells may play a role in cell homeostasis in the normal kidney and during renal injury.     

Fas and Fas ligand expression in cystic fibrosis airway epithelium

BACKGROUND: Cystic fibrosis (CF) is a genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene and defective expression of CFTR protein in epithelial cells. The main cause of mortality in CF is linked to chronic inflammatory and infectious airway processes. Recent studies have suggested perturbations in the apoptotic process in CF cell lines and enterocytes. A study was undertaken to investigate the expression of Fas and Fas ligand (FasL) in CF bronchial epithelium and CF tracheal cell lines. METHODS: Immunohistochemical staining for Fas (alkaline phosphatase anti-alkaline phosphatase) and FasL (immunoperoxidase) was performed in eight CF bronchial epithelial samples and four controls and immunohistochemical DNA fragmentation (TUNEL) was carried out in four CF patients and four controls. Immunofluorescence staining and flow cytometric analysis of Fas and FasL expression was performed in two human tracheal epithelial cell lines (HTEC) with normal and CF genotype. The dosage of serum soluble FasL was examined in 21 patients with CF and 14 healthy volunteers. RESULTS: FasL expression was markedly increased in patients with CF in both the ciliated and submucosal glandular bronchial epithelium compared with controls; Fas was similarly expressed in bronchial samples from controls and CF patients in both the ciliated epithelium and submucosal glands. High levels of DNA fragmentation were observed in CF but with some epithelial cell alterations. Serum concentrations of soluble FasL were frequently undetectable in patients with CF. In vitro, HTEC expressed Fas and FasL in both genotypes. A higher mean fluorescence intensity for FasL expression was noted in CF genotype HTEC with median (range) for six experiments of 74 (25-101) for CF cells and 42 (21-70) for non-CF cells. CONCLUSION: Fas/FasL interaction is probably implicated in the human CF airway apoptotic pathway. The mechanisms of induction of FasL expression and its role in inducing tissue damage or remodelling or in controlling local inflammatory cell apoptosis remain to be determined.     

Germ cell apoptosis induced by ureaplasma urealyticum infection

Aim: To study the effect of Ureaplasma urealyticum (UU) infection on germ cell apoptosis of male rats. Methods: Male rats were infected artificially with UU serotype 8 (T960). Morphological changes of germ cells in the seminiferous tubules and the lumen of the epididymides were observed under the light microscope. Fluorescence-conjugated polyclonal antibodies to Fas and Fas ligand (FasL) were used to localize Fas and FasL. TUNEL staining of germ cells and Sertoli cells was performed by the AKPase method. TUNEL-positive rate ( % positive cells) and TUNEL-positive area (area occupied by stained cells) were analysed by KS400 Image Analysis System. The DNA laddering analysis was performed by agarose gels electrophoresis. Results: In those rats infected with UU: (1) Exfoliated germ cells were dramatically increased. Many multinucleated giant cells were found in the seminiferous tubules and the lumen of the epididymides. (2) The number of TUNEL-positive cells and the TUNEL-positive area were significantly increased. (3) The expression of Fas and FasL in germ cells and Sertoli cells was up-regulated. (4) Discrete bands of fragmented DNA were found in the testicular cells. Conclusion: In male rats, germ cell apoptosis was increased in UU infection.     

HLA-G和Fas配体在肾透明细胞癌中的表达及意义

目的：探讨两种免疫抑制分子人类白细胞表面抗原HLA—G和Fas配体（FasL）与经典型肾透明细胞癌（ccRCC）分级和分期的相关性。方法：采用免疫组织化学方法对60例ccRCC标本石蜡切片进行检测,数据由SPSS软件进行统计分析。结果：肿瘤旁正常肾组织中无HLA—G表达;肾癌组织中,40例（66．7％）表达HLA—G,36例（60．0％）表达FasL。31例（51．7％）两者均表达,15例（25．0％）两者均不表达。在同一标本中,肿瘤侵犯脉管或淋巴结后,其HLA-G或FasL表达较原位肿瘤明显增强。统计分析显示HLA—G表达的阳性率和表达强度与肿瘤的分期、分级均呈正相关（P〈0．01）。FasL表达的阳性率与肿瘤分级呈正相关（P〈0．05）,而表达强度与肿瘤分期呈正相关（P〈0．01）。结论：ccRCC中HLAG和FasL的表达与肿瘤的分期、分级均呈正相关,与淋巴结转移有一定关系;晚期ccRCC高表达免疫抑制分子的机制需进一步研究。     

Expression of Fas and Fas ligand in human testicular germ cell tumours

In the present study, we analysed the expression of Fas ligand (FasL) and its cognate receptor Fas in 14 seminomatous testicular germ cell tumours (TGCT) and six normal testicular tissues obtained following orchiectomy. Tissue samples have been processed to prepare either total RNA or protein extracts or fixed and embedded in paraffin for immunohistochemistry (IHC) experiments. Quantitative RT-PCR experiments demonstrated in TGCT a significant ( p  < 0.01) increase of the FasL mRNA expression of 21.1 ± 5.4 fold, with respect to normal tissues. On the contrary, in the same cancer tissues, the levels of Fas mRNA were significantly ( p  < 0.01) reduced to 0.27 ± 0.06 fold. These observations were confirmed in western blot experiments showing a significant increase of FasL and a concomitant decrease of Fas proteins in testicular cancer tissues, with respect to normal testis. Moreover, IHC experiments showed a strong FasL immuno-reactivity in six out of eight TGCT samples analysed, while Fas immuno-positivity was found in cancer cells of only two TGCT tissues. In addition, in all tumour samples, infiltrating lymphocytes were Fas positive. However, no correlation could be observed between Fas or FasL mRNA variations and clinical parameters such as patient's age, TNM stage or tumour size. We also compared the serum levels of soluble FasL (sFasL) of 15 patients affected by seminomatous TGCT, of four patients with non-seminomatous TGCT and six age-matched healthy males. No significant differences in sFasL serum level could be identified. In conclusion, our data demonstrated that the majority of seminomas are characterized by an increased expression of FasL and a concomitant reduction of Fas, with respect to human normal testis, and that sFasL serum level is not a tumour marker for patients affected by TGCT.     

大肠癌浸润淋巴细胞Fas配基表达与癌细胞凋亡的关系

目的　研究结肠直肠癌浸润淋巴细胞Fas配基 (FasL)表达与癌细胞凋亡的关系。　方法　用免疫组化方法检测 86例结肠直肠癌及切缘正常大肠组织的Fas蛋白、FasL的表达 ;用TdT酶介导的DNA3′ OH末端 缺口染色方法检测癌细胞的调亡指数 ,并分析浸润淋巴细胞FasL表达与癌细胞凋亡指数的关系。　结果　 86例结肠直肠癌组织呈Fas蛋白染色阳性 5 3例 (6 1 6 % ) ,正常大肠组织则未见染色 ,癌组织旁浸润淋巴细胞FasL染色阳性 6 9例 (80 2 % )。癌组织Fas蛋白阳性组中 ,浸润淋巴细胞FasL染色程度与癌细胞凋亡指数呈正相关 (P <0 0 1) ,FasL染色越强 ,凋亡癌细胞越多。Fas蛋白阴性组中则不存在这种相关性。　结论　癌旁浸润淋巴细胞通过其表面的FasL与大肠癌细胞表面的Fas蛋白作用 ,是诱导癌细胞凋亡的途经之一。提高癌细胞Fas蛋白的表达及应用特异性Fas抗体 ,将为大肠癌治疗提供新思路。     

FasL、抗DR5单克隆抗体对结肠癌细胞株HT29的杀伤作用及其机制

目的 探讨FasL、抗DR5单克隆抗体(Anti-DR5 mAb)对结肠癌细胞株HT29的杀伤作用及机制.方法 采用逆转录-聚合酶链反应(RT-PCR)、噻唑蓝(MTT)比色法、DNA倍体分析,Western blot等.结果 HT29细胞表面Fas mRNA的表达低于DIL5 mRNA的表达.50 mg/L FasL和Anti-DR5 mAb对HT29细胞的杀伤率分别为(25.49±0.90)%和(48.90±3.15)%,这种作用呈剂量依赖性.流式细胞术分析细胞周期和凋亡实验表明FasL和Anti-DR5 mAb能够抑制HT29细胞的生长,并且诱导它的凋亡.25 mg/L FasL和Anti-DR5 mAb对HT29细胞的凋亡指数分别为(13.8±1.5)%和(22.6±1.1)%.FasL和Anti-DR5 mAb作用HT29细胞后,Caspase-3蛋白表达上升,bcl-2蛋白表达水平下降.结论 FasL、Anti-DR5 mAb能不同程度的诱导结肠癌细胞株HT29凋亡,其机制与其受体和Caspase-3、bcl-2的表达有关.     

New kids in the block: the role of FasL and Fas in kidney damage.

Fas ligand (FasL) is a lethal cytokine that promotes apoptosis through cross-linking of the Fas receptor, although it also has other, less well understood functions. The FasL/Fas system regulates immune and inflammatory responses. Evidence that FasL and Fas participate in kidney damage can be summarized as follows: 1) FasL is expressed by renal cells and its expression increases during kidney damage; 2) activation of the Fas receptor promotes apoptosis of non-stimulated or cytokine-primed renal cells in culture; 3) Fas agonists kill mesangial cells and induce glomerular injury in vivo, but can also reduce kidney damage by limiting injurious immunological responses; 4) mice with disrupted FasL/Fas systems are protected from acute tubular cell injury, although they develop autoimmune glomerulonephritis if other genetic predisposing factors are present. These facts imply that the FasL/Fas system can be considered a new target for therapeutic intervention in kidney damage. However, any therapeutic approach must consider interference with Fas in other cell systems. The complexities of the FasL/Fas system in the kidney are still far from clear.     

Pressure and endothelial coculture upregulate myocytic Fas-FasL pathway and induce apoptosis by way of direct and paracrine mechanisms

BACKGROUND: Pressurized endothelial cell (EC)-smooth muscle cell (SMCs) coculture significantly increases the apoptosis of SMCs. Our current hypothesis was that in EC-SMC coculture, pressure upregulates SMC apoptosis SMCs through EC-derived paracrine factors and that SMC apoptosis is induced through Fas-Fas ligand (FasL) activation. METHODS: Conditioned media (CM) from ECs and SMCs exposed to ambient or high pressure was transferred to recipient SMCs. SMCs were stained with terminal deoxynucleotide transferase-mediated deoxy uridine triphosphate nick-end labeling. Fas and FasL expression was assessed in SMC grown in monoculture, coculture with EC, pressurized monoculture, and pressurized coculture with EC. RESULTS: CM from pressurized ECs caused a 30% increase in SMC apoptosis compared with CM from control ECs (P < .05). Pressure increased Fas and FasL expression in monocultured and cocultured SMCs (1.6-fold and 2.3-fold for Fas [P < .05] and 1.65-fold and 1.7-fold for FasL [P < or = .05]). Coculture had synergistic effect on Fas expression and no effect on FasL expression. CONCLUSIONS: Pressure plays significant role in EC-SMC interaction, SMC apoptosis, and vascular remodeling.     

食管癌的Fas配体表达及意义

目的 检验Fas配体在食管癌细胞的表达,及其与食管癌浸润淋巴细胞、与食管癌浸润与转移的关系和对病人术后生存的影响。方法 采用免疫组化方法检测30例原发食管癌标本中Fas配体的表达,用CD45标记肿瘤浸润巴细胞。结果 76.6％的标本有Fas配体的表达,且不同TNM分期的病人表达水平差异显著,Fas配体的表达与食管癌中肿瘤浸润淋巴细胞数呈负相关,但Fas配体的表达与病人术后生存无显著关系。结论 Fas配体的表达有利于食管癌逃避免疫攻周,有利于其浸润与转移。     

Fas and Fas-ligand expression in human pancreatic cancer

OBJECTIVE: To investigate Fas and FasL expression in pancreatic tissues and cultured pancreatic cancer cell lines, and to assess the ability of anti-Fas antibodies to induce apoptosis. SUMMARY BACKGROUND DATA: Activation of the Fas receptor by Fas-ligand (FasL) results in apoptosis, and dysregulation of this pathway may contribute to abnormal cell proliferation. METHODS: Northern blotting and immunohistochemistry were used to compare Fas and FasL expression in normal and cancerous tissues. DNA 3'-OH end labeling was used to detect apoptotic cells. The effects of Fas activation on cell growth and signaling pathways were investigated in culture. RESULTS: Pancreatic cancers exhibited increased Fas RNA levels, whereas FasL mRNA levels were similar in both groups. Despite the colocalization of Fas and FasL in the cancer cells, an apoptotic signal was present in approximately 10% of these cells in only 2 of 16 cancer samples. Fas and FasL were coexpressed in all four cell lines, whereas Fas-associated phosphatase 1 was below the level of detection in all cell lines. Only COLO-357 cells underwent apoptosis after Fas activation. Apoptosis was associated with enhanced activation of jun kinase (JNK) and p38 mitogen-activated protein kinase (MAPK). In the presence of actinomycin D, Fas antibody also induced apoptosis in the other three cell lines. CONCLUSIONS: These results suggest that pancreatic cancer cells are resistant to Fas-mediated apoptosis by mechanisms excluding receptor downregulation or Fas-associated phosphatase upregulation and raise the possibility that Fas-mediated apoptosis may be dependent on the activation of the JNK/p38 MAPK pathway in these cells.     

Fas ligand-transfected myoblasts and islet cell transplantation

BACKGROUND: Expression of Fas ligand (FasL, CD95L) within the local environment of an allograft may protect from rejection by inducing apoptosis of infiltrating T cells. However, there is mounting evidence that ectopic expression of FasL stimulates an inflammatory response and targets the FasL-expressing tissue for destruction. Given the potential therapeutic applicability of FasL-based immune protection, we sought to determine whether ectopic FasL expression was detrimental and to analyze the inflammatory response induced by ectopic FasL expression in the absence of any confounding allo-immune responses. METHODS AND RESULTS: Two myoblast cell lines expressing different levels of functional FasL were produced. Co-implantation of FasL-expressing myoblasts with syngeneic islets allowed examination of the inflammatory response induced by ectopic FasL expression. In contrast to the suggested benefits of localized FasL expression, islets co-implanted with FasL-expressing myoblasts were destroyed in a vigorous inflammatory response predominated by neutrophils. Interestingly, FasL expression also had a marked anti-tumor effect. CONCLUSIONS: Unless FasL-dependent neutrophil-mediated inflammation can be prevented, it is unlikely that this strategy will be useful for preventing allograft rejection.