ABSTRACT
Lack of surface Fas expression is a main route for apoptotic resistance which is considered an important mechanism of tumorigenesis and tumor progression. Fas and FasL expressions in 110 non-small cell lung carcinomas (NSCLCs) were investigated to evaluate their roles in pulmonary carcinogenesis and to examine the clinicopathologic significance of Fas expression with its relationship with p53 and bcl-2 overexpressions. Immunohistochemical analysis using tissue microarray demonstrated that a large proportion of NSCLC patients (60%) showed lack of membranous Fas expression. The Fas-negative cases revealed the significantly lower survival rate than Fas-positive ones. Also, the loss of Fas receptor expression was found more frequently in advanced stage and higher nodal status. FasL protein was increased in most NSCLCs (89%) compared to normal lungs. p53 and bcl-2 overexpressions showed no association with Fas expression. Conclusively, reduced membranous Fas expression as a mechanism of apoptotic resistance is considered to play an important part of the pulmonary carcinogenesis, which may predict poor survival and have a bad prognostic influence. Increased FasL expression is thought to be a basis for the immune evasion in NSCLCs. The rare bcl-2 overexpression suggests that this anti-apoptotic protein is unlikely to play a role in the apoptotic resistance of NSCLCs.
Subject(s)
Female , Humans , Male , Middle Aged , fas Receptor/metabolism , Apoptosis , Carcinoma, Non-Small-Cell Lung/metabolism , Cell Survival , Comparative Study , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Korea/epidemiology , Lung Neoplasms/metabolism , Membrane Glycoproteins/metabolism , Oligonucleotide Array Sequence Analysis , Prognosis , Proto-Oncogene Proteins c-bcl-2/metabolism , Risk Assessment/methods , Risk Factors , Survival Analysis , Survival Rate , Biomarkers, Tumor/metabolism , Tumor Necrosis Factors/metabolism , Tumor Suppressor Protein p53/metabolismABSTRACT
PURPOSE: Androgen deprivation triggers a sequence of events that activates apoptotic cell death of the androgen-dependent epithelial cells within the rat ventral prostate, ultimately resulting in the involution of the gland. To investigate the mechanism of azaline B-dependent apoptosis in the rat ventral prostate, the regulation of apoptosis-related genes were examined. MATERIALS AND METHODS: Azaline B was subcutaneously injected in Sprague-Dawley rat. Fas receptor(Fas), Fas ligand(FasL), bcl-2 mRNA, and protein levels were detected by RT-PCR and Western blot. Azaline B-dependent apoptosis was determined by TUNEL and DNA fragmentation assay. Transacting factor of FasL promoter was identified by DNA footprinting and DNA mobility shift assay. RESULTS: The prostate regressed after azaline B treatment in rat, and the involuted ventral prostate regenerated after testosterone pretreatment. Apoptosis of the ventral prostate was detected by TUNEL assay and apoptotic DNA fragmentation assay after azaline B treatment. The levels of Fas and FasL mRNA and protein increased after azaline B treatment. In DNase I footprinting assay with FasL promoter using nuclear extract prepared from control prostate, at least two sites were protected: SP-1 binding site at -283bp and prostate-unidentified factor(P-UF) binding site at -247bp. SP-1 binding activity vanished in the nuclear extract prepared from azaline B-treated rats. In the DNA mobility shift assay, SP-1 binding activity decreased after azaline B treatment. Bcl-2 mRNA and protein were downregulated after azaline B treatment. CONCLUSIONS: These results suggest that Fas/FasL system and Bcl-2 are important to azaline B-dependent apoptosis in rat ventral prostate and that SP-1 is related to azaline B-dependent regulation of the FasL gene.
Subject(s)
Animals , Rats , fas Receptor , Apoptosis , Binding Sites , Blotting, Western , Cell Death , Deoxyribonuclease I , DNA , DNA Footprinting , DNA Fragmentation , Electrophoretic Mobility Shift Assay , Epithelial Cells , Fas Ligand Protein , Genes, bcl-2 , In Situ Nick-End Labeling , Prostate , Rats, Sprague-Dawley , RNA, Messenger , TestosteroneABSTRACT
Objective To investigate the modulation of FasL protein in colon cancer cells by interleukin 18 (IL 18) and it's effect on tumor cells counterattacking T lymphocytes. Methods By using Western blotting assay, FasL protein expression was examined in human colon cancer cell line SW620. The ratio of apoptosis of lymphocytes induced by tumor cells was studied by flow cytometry analysis. Results 10 ?g/L and 100 ?g/L IL 18 upregulated FasL protein expression in SW620 cell line, reaching the peak in 18 and 36 hours respectively, and returned to initial levels in 72 hours. The ratio of apoptosis of Jurkat cells induced by tumor cells increased in accordance with the upregulation of FasL protein. Conclusions IL 18 upregulates FasL protein expression in colon cancer cell line and enhances the ability of cancer cells to counterattack T lymphocytes.