The renal cell carcinoma lysis by a specific cytotoxic T cell clone is independent of the Fas/Fas-L cytotoxic pathway

The expression of Fas antigen at the surface of renal cell carcinoma and the susceptibility to Fas-mediated lysis by a tumor specific CTL clone were investigated. Renal cell carcinoma cell lines expressed Fas antigen and were susceptible to apoptosis mediated by antibodies to Fas/APO1. Using RT-PCR, we further showed that these cell lines expressed mRNA for Fas deleted transmembrane region, corresponding to a soluble form of Fas/APO-1. To investigate the role of the Fas/FasL pathway in the cytotoxic response against RCC cells, we analyzed the induction of Fas-L on a tumor specific T cell clone (CTL 8C2), previously generated against one RCC cell line. Fas-L expression on CTL 8C2 was detected by RT-PCR after stimulation with autologous tumor cells. However, the cytotoxic activity of CTL 8C2 was completely abolished when EGTA was added, suggesting that the cytolysis was mainly mediated by a Ca++-dependent pathway, perforin/granzyme-based.     

二黄糖肾康对糖尿病肾病大鼠肾脏细胞凋亡及PI3 K/AKT信号转导系统的影响

目的 观察二黄糖肾康对糖尿病肾病(DN)大鼠细胞凋亡及PI3 K/AKT信号转导系统的影响. 方法 SD大鼠单侧肾切除加腹腔注射链脲佐菌素(STZ)复制DN模型,每日二黄糖肾康灌胃,8 w后流式细胞术检测细胞凋亡数目及调控因子Bax、Bcl-2、Fas、Fas-L的蛋白表达,采用Western 印迹方法检测细胞内磷酸化Akt蛋白质的表达.结果 二黄糖肾康明显减少DN大鼠肾脏皮质细胞凋亡数目,降低Bax、Fas、Fas-L的的蛋白表达,增加Bcl-2的蛋白表达,激活PI3 K/AKT信号通路.结论 二黄糖肾康能有效降低肾脏细胞凋亡,激活PI3 K/AKT信号通路.     

Upregulation of osteoblast apoptosis by malignant plasma cells: a role in myeloma bone disease

Typical features of multiple myeloma (MM) are osteolytic lesions and severely affected bone regeneration. This study of 53 MM patients demonstrates an enhancement of osteoblast cytotoxicity by malignant myeloma cells via the upregulation of apoptogenic receptors, including Fas ligand (Fas-L) and tumour-necrosis-factor-related apoptosis inducing ligand (TRAIL). Both were significantly increased in the marrow myeloma cells of patients with extensive osteolytic lesions in a fashion similar to the highly malignant human myeloma cell line MCC-2. Osteoblasts from these subjects over-expressed Fas and death receptor (DR) 4/5 and underwent dramatic apoptosis when co-cultured with either MCC-2 or autologous myeloma cells. In osteoblast and myeloma cell co-cultures, monocyte chemoattractant protein 1 (MCP-1) mRNA was upregulated in osteoblasts from patients with severe bone disease in parallel with increased CC-chemokine receptor R2 (CCR2) expression, the ligand of MCP-1, in the myeloma cells. This chemokine was shown to activate malignant cell migration in vitro. An upregulation of ICAM-1 expression occurred in osteoblasts from patients with active skeleton disease. This upregulation appeared to be an effect of malignant plasma cell contact, as MCC-2 co-culture greatly enhanced ICAM-1 production by resting osteoblasts from patients without skeleton involvement. Our results suggest that osteoblasts in active myeloma are functionally exhausted and promptly undergo apoptosis in the presence of myeloma cells from patients with severe bone disease. It is suggested that this cytotoxic effect plays a pivotal role in the pathogenesis of defective bone repair.     

Effect of Acanthopanax giraldii Harms Var.Hispidus Hoo polysaccharides on the human gastric cancer cell line SGC-7901 and its possible mechanism

Objective To study the inhibitory effect of Acanthopanax giraldii Harms Var.Hispidus Hoo polysaccharides (AGP) onSGC-7901 gastric cancer cells and its possible mechanism. Methods Cell doubling time analysis, colony forming assay and MTT assay were adopted to study the inhibitory effect and its characteristics. We also analyzed the amount of protein expressed by oncogenes, antioncogenes and cell factors using flow cytometric analysis.Results AGP inhibited the proliferation of SGC-7901 cells and cell colony forming ability. AGP did not inhibit the viability and function of lymphocytes of peripheral blood in healthy subjects and human embryonic tenocytes, except for the highest dosage of AGP ( P <0. 05), which slightly inhibited the viability and function of the two types of normal cells. AGP inhibited the viability and function of SGC-7901 cells, except for the lowest dosages of AGPⅠ and AGPⅢ. There was a dose-effect relationship between the dosage of the AGP andSGC-7901 cells.The effect of the AGP at the molecular level was associated with the low protein expression of the c-myc and bcl-2 genes and the high protein expression of the p53, bax, fas and fas-L genes, as well as the cell factor TGFβ(1).The inhibitory effect of AGP was weaker than that of CDDP, but was stronger than that ofVitamine C. Conclusions Acanthopanax giraldii Harms Var.Hispidus Hoopolysaccharides selectively inhibited the proliferation, the colony forming ability, and the viability and function of human gastric cancer cells through the low protein expression of c-myc, bcl-2 and the high protein expression of p53, fas, fas-L and the cell factor TGFβ(1). The different inhibitory characteristics on the normal cells and cancer cells are possibly caused by gene and the cell factor expressions.     

Mechanisms and biomarkers of immune quiescence in kidney transplantation

This review discusses the current understanding of biomarkers of immune quiescence based on reviews of published literature in kidney transplant operational tolerance and mechanistic studies based on a better characterization of the stable, well-functioning renal allograft.     

Expression pattern of apoptotic markers in vestibular schwannomas

The Fas-Fas-L system plays a major role in the regulation of apoptosis and hence in growth in benign and malignant human tumors. As the factors regulating cell death in benign schwannomas are not well understood, we investigated the immunoexpression of the Fas-Fas-L system, as well as that of the anti-apoptotic factor Bcl-2 and the pro-apoptotic factor Bax in 14 sporadic vestibular schwannomas, and related the findings to the MIB-1 labeling index as a marker for cell proliferation. Whereas cytoplasmic Fas expression was seen in only one tumor (7%), Fas-L was found in the nuclei of 12 schwannomas (86%). Bcl-2 expression was found in the cytoplasm of 9 tumors (64%), and Bax was found in 10 out of 14 schwannomas (71%). No significant correlations between different labeling indices were observed. However, schwannomas expressing Bax tended to show a higher proliferation rate as revealed by the MIB-1 LI, suggesting a balance between cell proliferation and cell death. Our study further showed that Fas-L is present in most vestibular schwannomas; however, due to the lack of Fas expression, apoptosis in vestibular schwannomas does not seem to be mediated via the Fas-Fas-L system.     

Soluble HLA class I/CD8 ligation triggers apoptosis in EBV-specific CD8+ cytotoxic T lymphocytes by Fas/Fas-ligand interaction

In the present study, we report that allogeneic soluble HLA class I (sHLA-I) molecules isolated from serum induce apoptosis on EBV-specific CD8⁺ Fas⁺ cytotoxic T lymphocytes (CTL). CTL apoptosis is induced by the binding of sHLA-I molecules to CD8 and its extent depends on the time of incubation with sHLA-I molecules. Apoptosis is triggered by the interaction of Fas⁺ CTL with soluble Fas-ligand, which is released following the binding of sHLA-I antigens to CD8 molecules. These results suggest that sHLA-I molecules may regulate immune responses by inducing apoptosis in virus-specific CTL.     

071 Fas和Fas-L在鼻息肉组织中的研究进展

鼻息肉(nasal polyps,NP)是耳鼻咽喉科的常见多发病之一,其发病机理至今仍未完全阐明.近年研究发现NP上皮细胞过度增殖和炎性细胞凋亡的抑制在其发病过程中具有重要作用.Fas/Fas-L系统的生理功能在于通过对细胞凋亡(apoptosis)的调节,限制某些细胞群落的过分膨胀或过分萎缩,参与正常细胞增殖、分化和凋亡动态平衡的维持,在临床多种疾病的发生过程中具有重要作用.本文就NP的病因研究概况和Fas/Fas-L在NP发病学中的作用与机制作一综述.