Significance of serum soluble Fas ligand in patients with bladder carcinoma

BACKGROUND: The interaction of Fas and Fas ligand (FasL) plays an important role in cytotoxic T-lymphocyte-mediated and natural killer cell-mediated apoptosis against tumor cells. Circulating soluble FasL (sFasL) has been suggested to provide protection from Fas-mediated apoptosis. The current study examined this possibility in patients with bladder carcinoma. METHODS: The levels of sFasL in the serum of 163 patients with bladder carcinoma were determined using an enzyme-linked immunoadsorbent assay. Antiautologous tumor cytotoxic activity was assessed by the 12-hour chromium isotope ((51)Cr) release assay. RESULTS: The mean serum level of sFasL in patients with bladder carcinoma was 2.5-fold higher than that in healthy donors. The level of serum sFasL in patients with muscle-invasive bladder carcinoma was 2.5-fold higher than that in patients with superficial bladder carcinoma. In addition, serum sFasL levels in patients with T1 and Tis bladder carcinoma was 2-fold and 2.7-fold higher, respectively, than levels in patients with Ta bladder carcinoma. The serum level of patients with sFasL in Grade 3 bladder carcinoma were 2.4-fold and 1.7-fold higher than that in patients with Grade 1 and Grade 2 bladder carcinoma, respectively. Patients with Ta bladder carcinoma with a low level of serum sFasL (less than the median value) had a longer postoperative tumor-free interval than patients with a high sFasL level (greater than the median value) in the 5-year follow-up. There was an apparent inverse correlation between the level of serum sFasL and antiautologous tumor cytotoxic activity. CONCLUSIONS: The results of the current study demonstrated that the level of serum sFasL is correlated with both disease progression and increase in the tumor grade, and that an elevated serum sFasL level predicted early recurrence in patients with Ta bladder carcinoma. These findings suggest that elevated serum sFasL levels might be associated with a greater risk of disease progression and recurrence in patients with bladder carcinoma.     

Alginate encapsulated cells secreting Fas-ligand reduce lymphoma carcinogenicity

Fas ligand (CD95L/APO-1) is considered as a potent anti-tumor agent due to its mediated cell death properties. We have designed a polymeric microencapsulation system, which encapsulates soluble FasL secreting cells. The encapsulated cells continuously release soluble FasL (sFasL) at the tumor site, while the device protects the encapsulated cells from the host immune system. The potential and efficacy of this system are demonstrated in vitro and in vivo for tumor inhibition. Polymeric microcapsules composed of Alginate Poly-l-lysine were optimized to encapsulate L5 secreting sFasL cells. The expression and anti-tumor activities of the sFasL were confirmed in vitro and tumor inhibition was studied in vivo in SCID mice bearing subcutaneous lymphoma tumors. In vitro, sFasL secreted by the encapsulated L5-sFasL cells was biologically active, inhibited proliferation and induced apoptotic cell death in Fas sensitive tumor cells. Mice injected with encapsulated L5-sFasL cells on the day of tumor injection or 10 days after tumor injection showed significant reduction in tumor volume, of 87% and 95%, respectively. Our findings show that encapsulated cells expressing sFasL can be used as a local device and efficiently suppress malignant Fas sensitive tumors with no side effects.     

Fas and Fas ligand: Expression and soluble circulating levels in bile duct carcinoma

Alteration of the Fas receptor (Fas)-/ligand (FasL) system including their soluble forms (sFas and sFasL) is thought to be one of the mechanisms preventing the immune system from rejecting the tumor cells. We investigated the tissue expression of Fas, FasL, and the alteration of sFas and sFasL in patients with bile duct carcinoma. Thirty-four samples were immunostained for Fas and FasL, and levels of sFas and sFasL in the serum of 62 patients were determined using an enzyme-linked immunoadsorbent assay. Patients with strongly positive Fas levels showed significantly better prognosis than those with weakly positive or negative Fas levels. The mean serum levels of sFas in healthy individuals were significantly higher in patients with carcinoma. However, the mean serum levels of sFasL were significantly lower in the patients with carcinoma. Serum levels of sFas and sFasL might be a significant and independent prognostic parameter in patients with bile duct carcinoma.     

Circulating soluble Fas ligand in patients with gastric carcinoma

BACKGROUND: The Fas/Fas ligand (FasL) system is involved in cancer cell death induced by the immune system. Most of the tumors may escape the host immune attack by imitating themselves as immune-privileged sites by overexpressing FasL. FasL is synthesized as a membrane-bound protein that can be cleaved to the soluble isoform (sFasL). The objectives of this work were to determine whether the serum concentrations of sFasL in patients with gastric carcinoma were correlated with clinicopathologic features and survival rates. METHODS: The authors examined the circulating sFasL concentration in 43 healthy people and 166 primary gastric carcinoma patients at the time of diagnosis by enzyme linked immunoadsorbent assay. The results were categorized by clinical and histopathologic variables. RESULTS: The serum sFasL levels of healthy subjects were all less than 0.1 ng/mL. Among the 166 gastric carcinoma patients, the median concentration of sFasL was 0.04 ng/mL. There were no significant differences between the healthy controls and the gastric carcinoma patients group (P = 0.738). The sFasL levels were significantly increased in patients with gastric carcinoma in a manner reflective of the disease stages such as the depth of tumor invasion, lymph node metastasis, and distant metastasis. The authors determined the cutoff value (0.08 ng/mL) as a 90th percentile of healthy controls. The survival analysis demonstrated that patients with high sFasL levels had a worse prognosis than those with low levels (P < 0.001). Multivariable analysis confirmed that the sFasL concentration was an independent prognostic indicator of overall survival (P = 0.041). CONCLUSIONS: Our results indicated that sFasL concentrations could not be a new marker for early detection of gastric carcinoma but a prognostic tumor marker for the assessment of the progression of advanced gastric carcinoma.     

Fas/FasL与肿瘤局部及全身性免疫抑制

Ｆａｓ（ＣＤ９５）及其配体（ＦａｓＬ）属ＴＮＦ和ＮＧＦ受体家族,Ｆａｓ在多种质细胞表面均有表达。Ｆａｓ与ＦａｓＬ结合可引起多种细胞产生凋亡。近年来研究发现ＦａｓＬ在多种种瘤细胞的表面和细胞质中表达,同时已证实肿瘤周围激活的淋巴细胞表面有Ｆａｓ的表达,而这些淋巴细胞的凋亡异常增加,因此推测表达ＦｓａＬ的肿瘤细胞能诱发淋巴细胞的异常凋亡或抑制其功能,肿瘤细胞表面表达的ＦａｓＬ可能在局部免疫抑制中起着重     

Control of ocular tumor growth and metastatic spread by soluble and membrane Fas ligand

Fas ligand (FasL) can be either membrane bound, or cleaved by metalloproteinases (MMP) to produce a soluble protein. The two different forms of FasL are reported to have opposite functions-membrane-bound FasL (mFasL) is proinflammatory and soluble FasL (sFasL) is antiinflammatory. We previously showed that, within the immune-privileged eye, tumors expressing high levels of mFasL overcame the suppressive ocular environment, triggered an inflammatory response, and were subsequently rejected. By contrast, eye tumors expressing low levels of mFasL grew progressively. To evaluate the effect of sFasL on the tumor growth and metastatic potential of ocular FasL-expressing tumors, we compared tumor cell clones that expressed equal amounts of (low) mFasL in the presence or absence of sFasL. Tumor cells transfected with a modified FasL gene expressed only mFasL (noncleavable), grew progressively within the eye, and induced systemic protective immunity that prevented metastatic spread of tumor cells to the liver. Unexpectedly, tumors transfected with wild-type FasL (wtFasL; cleavable), which could produce both sFasL and mFasL, elicited considerably more inflammation and grew more slowly within the eye. However, the cleavable wtFasL eye tumors failed to trigger protective immunity and gave rise to liver metastases. Interestingly, exposure to the ocular environment was required for the wtFasL tumors to gain metastatic potential. We conclude that the fate of FasL-expressing tumors is determined by a combination of the following: (a) the relative proportion of membrane and sFasL, and (b) the local environment that determines the extent of FasL cleavage.     

Expression of ADAM10, Fas,FasL and Soluble FasL in Patients with Oral Squamous Cell Carcinoma (OSCC) and their Association with Clinical-Pathological Parameters

ADAM10 has been implicated in the progression of various solid tumors. ADAM10 regulates the cleavage of the FasL ectodomain from the plasma membrane of different cell types, generating the soluble FasL fragment (sFasL). Currently, there are few studies in oral squamous cell carcinoma (OSCC) that correlate levels of ADAM10 and FasL in the tumor microenvironment with clinical parameters of the disease. To determine the expression of ADAM10, Fas, FasL and sFasL in patients with OSCC and its association with TNM stage. Twenty-five patients with OSCC and 25 healthy controls were included. Biopsies of tumor tissue from patients with OSCC and buccal mucosa in controls were obtained. ADAM10, Fas, and FasL were analyzed by Western blotting. sFasL was quantified by ELISA. ADAM10 and Fas decreased significantly in OSCC compared with controls. Relatedly, within the OSCC group, Fas and ADAM10 decreased in accordance with tumor disease stage; in stages I/II, as well as in tumors of smaller diameter (T1-T2), ADAM10 showed higher levels when compared to patients with T3-T4 tumors and in stage III-IV. FasL in the tumor microenvironment and serum FasL showed no significant differences between both groups. Levels of complete FasL and cleaved FasL were positively correlated in controls; this correlation is preserved in patients with tumors in early stages (I-II), but is lost in later stage (III-IV). The dysregulation of ADAM10, Fas and FasL could be useful indicators of the progression and severity of OSCC.     

lenalidomide enhances natural killer cell and monocyte-mediated antibody-dependent cellular cytotoxicity of rituximab-treated CD20+ tumor cells

PURPOSE: Lenalidomide has significant activity in myelodysplastic syndromes, multiple myeloma, and non-Hodgkin's lymphoma (NHL). In previous studies, natural killer (NK) cell expansion by lenalidomide was shown to enhance the cytotoxic effect of rituximab. This study assessed the ability of lenalidomide to enhance antibody-dependent cellular cytotoxicity (ADCC) in rituximab-treated NHL cell lines and primary tumor cells from patients with B-cell chronic lymphocytic leukemia (B-CLL) in vitro. EXPERIMENTAL DESIGN: An in vitro ADCC system was used to assess the ability of lenalidomide to enhance human NK cell and monocyte function in response to rituximab. RESULTS: Lenalidomide directly enhanced IFN-gamma production via Fc-gamma receptor-mediated signaling in response to IgG. It was also a potent enhancer of NK cell-mediated and monocyte-mediated tumor cell ADCC for a variety of rituximab-treated NHL cell lines in vitro, an effect that was dependent on the presence of antibody and either interleukin-2 or interleukin-12. Lenalidomide also enhanced the ability of NK cells to kill primary tumor cells derived from three patients with B-CLL who have been treated previously with fludarabine plus cyclophosphamide. Enhanced NK cell ADCC was associated with enhanced granzyme B and Fas ligand expression and could be inhibited by a granzyme B inhibitor and partially inhibited by antibody to FasL. Enhanced NK cell Fc-gamma receptor signaling is associated with enhanced phosphorylated extracellular signal-related kinase levels leading to enhanced effector function. CONCLUSIONS: These findings suggest that lenalidomide has the potential to enhance the rituximab-induced killing of NHL cell lines and primary B-cell chronic lymphocytic leukemia cells via a NK cell-mediated and monocyte-mediated ADCC mechanism in vitro, providing a strong rationale for the combination of lenalidomide with IgG1 antibodies to target tumor-specific antigens in patients with cancer.     

Lack of Correlation Between Clinical Characteristics and Serum Soluble Fas Ligand Levels in Patients with Multiple Myeloma

Multiple myeloma is characterized by the accumulation of malignant plasma cells in the bone marrow and rarely cured by chemotherapy. Villunger et al. showed that the neoplastic plasma cells express Fas ligand (FasL), which transmits a signal of apoptosis upon ligation to Fas, and suggested that the FasL suppresses the T-cells activated against malignant cells, resulting in escape from tumour immunity. We examined serum soluble FasL (sFasL) levels in 35 multiple myeloma patients to evaluate the correlation between sFasL levels and clinical characteristics. The serum sFasL levels were not affected by the disease status, serum monoclonal protein levels, or other prognostic factors. We could not determine whether the expression of FasL is involved in the poor clinical course of the disease.     

Lack of correlation between clinical characteristics and serum soluble Fas ligand levels in patients with multiple myeloma.

Multiple myeloma is characterized by the accumulation of malignant plasma cells in the bone marrow and rarely cured by chemotherapy. Villunger et al. showed that the neoplastic plasma cells express Fas ligand (FasL), which transmits a signal of apoptosis upon ligation to Fas, and suggested that the FasL suppresses the T-cells activated against malignant cells, resulting in escape from tumour immunity. We examined serum soluble FasL (sFasL) levels in 35 multiple myeloma patients to evaluate the correlation between sFasL levels and clinical characteristics. The serum sFasL levels were not affected by the disease status, serum monoclonal protein levels, or other prognostic factors. We could not determine whether the expression of FasL is involved in the poor clinical course of the disease.     

Expression of a soluble decoy receptor 3 in patients with diffuse large B-cell lymphoma predicts clinical outcome

The soluble decoy receptor 3 (DcR3) is a member of the TNF receptor superfamily. It is regarded as a decoy receptor released from tumor cells to escape host immune response by neutralizing the cytotoxic and immunomodulatory effects of FasL, LIGHT and TL1A. Overexpression of DcR3 has been observed in several human malignancies; however, only limited information exists on the role of DcR3 in non-Hodgkin lymphoma especially for B-cell origin. In the current study, the expression profile of DcR3 was analyzed by RT-PCR and immunohistochemistry (IHC) in a set of lymphoma cell lines including T-cell and B-cell lymphomas. The result demonstrated that overexpression of DcR3 was detected in most T-cell lymphoma cells, which was consistent with previous reports. Interestingly, overexpression of DcR3 was also detected both in the B-cell lymphoma cell lines and diffuse large B cell lymphoma (DLBCL) patients. DcR3 overexpression was associated with a worse prognosis in DLBCL patients (p=0.05). An in vitro study showed that neutralization of DcR3 increased the percentage of doxorubicin-mediated apoptosis in two B-cell lymphoma cell lines, which indicated the possibility of DcR3 mediated chemo-resistance in B-cell lymphomas. We suggest that overexpression of DcR3 is associated with a worse prognosis in DLBCL and the possible mechanism may act through the increase of chemo-resistance of lymphoma cells.     

Plasma soluble Fas ligand concentration: decrease in elderly men and increase in patients with gastric carcinoma

Fas ligand (FasL), which induces apoptosis against Fas-expressing cells, has been found to be expressed on various cell types including cancer cells. Membrane-bound FasL is cleaved to release soluble FasL (sFasL). Although serum or plasma sFasL concentration has been reported to increase in various diseases, sFasL concentration in healthy normal persons has not been fully studied. There have been few reports on sFasL concentrations in patients with carcinomas. We measured plasma sFasL concentrations using an enzyme-linked immunosorbent assay in 155 healthy volunteers (70 males and 85 females with an average age of 41.5+/-15.4) and 112 patients with gastric carcinoma (76 males and 36 females with an average age of 62.3+/-11.5). A significant negative correlation existed between age and plasma sFasL concentration in healthy volunteers. sFasL concentrations in males were significantly lower than those in females. Plasma sFasL levels were significantly higher in patients with gastric carcinoma than in healthy volunteers when male subjects aged 50 or older were analyzed, although no significant difference existed between the groups in the age bracket of 35 to 49. Male patients aged 50 or older with stage 1B or 2 tumors showed significantly higher plasma sFasL concentrations than those with stage 1A tumors or those with stage 3 or 4 tumors. In conclusion, age- and gender-matched controls should be used when plasma sFasL concentration is investigated. The origin and physiological or clinical significance of plasma sFasL in healthy volunteers and gastric cancer patients remain to be clarified.     

Plasma Fas ligand, an inducer of apoptosis, and plasma soluble Fas, an inhibitor of apoptosis, in advanced melanoma

The transmembrane receptor Fas/APO-1, together with its protein-binding partner (Fas ligand), is a key regulator of programmed cell death and induces apoptosis when it binds Fas ligand (FasL) or soluble Fas ligand (sFasL). However, soluble Fas (sFas) blocks apoptosis by inhibiting binding between Fas and FasL or sFasL. At present, the status of sFas and sFasL in metastatic malignant melanoma remains unknown. This study sought to evaluate the relationship between plasma levels of sFas and/or sFasL and clinical response in 45 metastatic malignant melanoma patients treated by biochemotherapy. sFas and sFasL were measured by specific enzyme-linked immunosorbent assay (ELISA) tests in the sera from patients and 34 healthy donors. Overall, sFas and sFasL levels in patients were significantly higher (P < 0.0001) than in healthy donors. Before the biochemotherapy treatment the sFas level was about the same in biochemorefractory (n = 26) as in responder patients (n = 19). In contrast, the sFasL level was very high only in biochemorefractory patients. At the end of the treatment, in biochemorefractory patients the sFas level was extremely significantly increased (P < 0.0001) and a significant decrease in the plasma levels of sFasL was observed (P = 0.0002). In responder patients, no change in sFas and sFasL was detected. In conclusion, elevated levels of sFas and sFasL might be associated with poor prognosis in advanced melanoma; their possible role in the regulation of apoptosis in influencing the response to biochemotherapy should be further explored.     

Antibody-based fusion proteins to target death receptors in cancer

Ideally, an immunotoxin should be inactive ‘en route’, acquire activity only after tumor cell surface binding and have no off-target effects towards normal cells. In this respect, antibody-based fusion proteins that exploit the tumor-selective pro-apoptotic death ligands sFasL and sTRAIL appear promising. Soluble FasL largely lacks receptor-activating potential, whereas sTRAIL is inactive towards normal cells. Fusion proteins in which an anti-tumor antibody fragment (scFv) is fused to sFasL or sTRAIL prove to be essentially inactive when soluble, while gaining potent anti-tumor activity after selective binding to a predefined tumor-associated cell surface antigen. Importantly, off-target binding by scFv:sTRAIL to normal cells showed no signs of toxicity. In this review, we highlight the rationale and perspectives of scFv:TRAIL/scFv:sFasL based fusion proteins for cancer therapy.     

Targeting B-lymphocyte stimulator/B-cell activating factor and a proliferation-inducing ligand in hematologic malignancies

B-lymphocyte stimulator/B-cell activating factor (BLyS/BAFF) and a proliferation-inducing ligand (APRIL), members of the tumor necrosis family of ligands, are expressed by monocytes, macrophages, and dendritic cells, and increased expression of these ligands is noted in lymphomas and plasma cell malignancies. BLyS and APRIL are essential for the survival of normal and malignant B lymphocytes, and altered expression of BLyS or APRIL or the receptors B-cell maturation, transmembrane activator and calcium-modulating cyclophilin ligand interactor, or BAFF-R have been reported in various B-cell malignancies, including B-cell non-Hodgkin's lymphoma, chronic lymphocytic leukemia, Hodgkin's lymphoma, multiple myeloma, and Waldenstrom's macroglobulinemia. Levels of BLyS (in the tumor and in the serum) increased with the transformation of the tumors to a more aggressive phenotype. A high BLyS level inversely correlated with a poor median overall survival, presence of constitutional symptoms, and increased levels of lactate dehydrogenase in patients with non-Hodgkin's lymphoma. Additionally, patients who responded to therapy had a lower BLyS level than those with progressive disease. Several agents targeting BLyS and APRIL are currently being pursued in phase I clinical studies in patients with B-cell malignancies.     

B细胞淋巴瘤中Fas和FasL蛋白的表达及其意义

背景与目的:以往研究表明,Fas/FasL是细胞凋亡的诱导基因,有许多肿瘤的发生都与Fas/FasL功能失调及表达异常有关,本研究旨在通过对淋巴瘤及良性淋巴组织中Fas/FasL基因蛋白表达规律的研究,为诊断淋巴瘤提供新的观察指标及实验依据。方法:对确诊的92例B细胞淋巴瘤石蜡标本及20例良性淋巴组织石蜡标本用免疫组化方法进行Fas和FasL蛋白表达的检测。结果:Fas主要表达在细胞膜上。FasL主要表达在细胞浆,部分表达在细胞核。B细胞淋巴瘤中Fas蛋白总阳性率为66.3%,FasL蛋白总阳性率为67.4%,良性淋巴组织中Fas及FasL蛋白表达阳性率均为60.0%。淋巴瘤组织与良性淋巴组织之间Fas及FasL蛋白表达差异无显著性(P>0.05)。但阳性细胞在良恶性淋巴组织之间分布部位不同。淋巴瘤各亚组之间Fas及FasL蛋白表达差异有显著性(P<0.05)。Fas蛋白表达在弥漫大B细胞淋巴瘤(diffuselargeB-celllymphoma,DLBL)(87.2%)高于滤泡细胞淋巴瘤(follicularlymphoma,FL)(64.5%)及小细胞淋巴瘤(smallcelllymphoma,SLL)(31.8%);FasL蛋白表达在DLBL(89.7%)高于FL(67.7%)及SLL(27.3%)。Fas及FasL的蛋白表达与性别、年龄、部位无关。结论:Fas及FasL的阳性率不能作为鉴别B细胞淋巴瘤良恶性的指标,而Fas和FasL在良恶性细胞中分布部位不同可做为参考     

Hypermethylation of death-associated protein (DAP) kinase CpG island is frequent not only in B-cell but also in T- and natural killer (NK)/T-cell malignancies

Death-associated protein (DAP) kinase is a pro-apoptotic serine/threonine kinase with a death domain, which is involved in apoptosis induced by interferon-γ, tumor necrosis factor-α, and Fas ligand. Down-regulation of DAP kinase gene expression by hypermethylation of its promoter region might result in resistance to apoptotic cell death, and could provide a basis for tumor development. In the present study, we employed methylation-specific polymerase chain reaction to examine the methylation status of CpG islands in the DAP kinase gene in 19 cases of T-cell malignancies (including eight adult T-cell leukemia/lymphoma), 24 of natural killer (NK)/T-cell, and 34 of B-cell. Frequency of methylation was significantly higher in B-cell (27 of 34, 79.4%) than in T-cell malignancies (nine of 19, 47.4%) (P<0.05). Fifteen of 24 (62.5%) NK/T-cell lymphomas showed DNA methylation. One B-cell lymphoma cell line with DNA methylation was resistant to apoptotic stimuli, and treatment of the cells with a demethylating agent restored apoptotic cell death. These findings suggested that suppression of DAP kinase expression by DNA methylation might play a substantial role in the development of not only B-cell, but also T- and NK/T-cell lymphomas. (Cancer Sci 2003; 94: 87–91)     

Soluble Fas-ligand (sFasL) in Human Astrocytoma Cyst Fluid is Cytotoxic to T-cells: Another Potential Means of Immune Evasion

Gliomas of all grades have been shown to express FasL, an apoptosis-inducing protein. Because of the ability of FasL to be cleaved from cell surfaces by metalloproteinases, soluble FasL can be released by FasL bearing cells into surrounding tissues. In the present study, we demonstrate the presence of sFasL in the cyst fluids of astrocytomas. Additionally, a human T-cell line, Jurkat, exposed to astrocytoma cyst fluid resulted in significantly increased cytotoxicity as compared to controls, an effect blocked by FasL neutralizing antibodies. This suggests that sFasL, may be utilized as a means of escaping immune surveillance by these tumors.     

FasL EXPRESSION IN HUMAN COLON CARCINOMAS

Fas and FasL are the members of the tumor necrosis factor (TNF) receptor and TNF families, respectively[1, 2]. Upon oligomerization of Fas either with FasL[3] or with agonistic antibodies[4], it confers an apoptotic signal to Fas-sensitive cells to induce apoptosis of the target cells[5]. The Fas/FasL system plays an important role for tumor cells to escape the host's immune surveillance during tumor formation. On one hand, tumor cells down-regulate expression of Fas on the tumor cell…