Chromogranin A and tumor necrosis factor-alpha (TNF) in chronic heart failure.
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Case-Control Studies↗
Biomedical subjects
A Corti
Publications and source records attributed to A Corti.
Enhancement of tumor necrosis factor alpha antitumor immunotherapeutic properties by targeted delivery to aminopeptidase N (CD13).
The clinical use of tumor necrosis factor alpha (TNF) as an anticancer drug is limited to local treatments because of its dose-limiting systemic toxicity. We show here that murine TNF fused with CNGRC peptide (NGR-TNF), an aminopeptidase N (CD13) ligand that targets activated blood vessels in tumors, is 12-15 times more efficient than murine TNF in decreasing the tumor burden in lymphoma and melanoma animal models, whereas its toxicity is similar. Similarly, human NGR-TNF induced stronger antitumor effects than human TNF, even with 30 times lower doses. Coadministration of murine NGR-TNF with a CNGRC peptide or an anti-CD13 antibody markedly decreased its antitumor effects. Tumor regression, induced by doses of murine NGR-TNF lower than the LD50, was accompanied by protective immunity. In contrast, no cure was induced by TNF at any dose. These results suggest that targeted delivery of TNF to CD13 may enhance its immunotherapeutic properties. Moreover, these findings reveal the potential of tumor homing peptides to generate a new class of recombinant cytokines that compared to immunocytokines have a simpler structure, could be easier to produce and are potentially less immunogenic.
Animals↗
Increased levels of clusterin (SGP-2) mRNA and protein accompany rat ventral prostate involution following finasteride treatment.
Finasteride is a well-known inhibitor of the prostatic enzyme 5 alpha-reductase type 2 which prevents conversion of testosterone into 5 alpha-dihydrotestosterone, the active intraprostatic androgen, which causes prostate involution through a combination of cell atrophy and cell death. The drug is widely used to improve symptoms of benign prostatic hyperplasia in man. Clusterin, a glycoprotein which is generally up-regulated under conditions inducing cell atrophy or organ involution, is produced at a high level in the regressing rat ventral prostate following androgen ablation. According to several authors, clusterin does not respond to finasteride treatment, suggesting a different action of testosterone and 5 alpha-dihydrotestosterone. We show here that, under our conditions, finasteride was capable of inducing production of both clusterin mRNA and protein in the rat ventral prostate. In fact, by using different and converging techniques, such as Northern hybridization, in situ hybridization histochemistry and immunohistochemistry, we were able to show a strong induction of the clusterin gene in the epithelial cell population of the gland. The response to finasteride, which was similar to that seen with castration, occurred with a delay of a few days. In situ and immunohistochemistry experiments indicated that both orchidectomy and finasteride administration resulted in increased transition of the epithelial cells from the columnar to the cuboidal (atrophic) shape, and this was accompanied by an increased intensity of the signal for clusterin. Thus, it appears that induction of clusterin is part of the molecular process leading to prostate involution caused by either orchidectomy or finasteride administration.
5-alpha Reductase Inhibitors↗
Immunohistochemistry of HFE in the duodenum of C282Y homozygotes with antisera for recombinant HFE protein.
BACKGROUND AND OBJECTIVE: HFE is a class-I MHC related protein which carries the C282Y mutation in most patients with hereditary hemochromatosis, an iron overload disease. HFE protein is expected to have a relevant role in the regulation of duodenal iron absorption, and HFE protein was immunohistochemically identified in the crypt cells. The aim of the work was to analyze whether the C282Y mutation affects HFE accumulation in the duodenum. DESIGN AND METHODS: We developed antisera for the extracellular portion of recombinant human HFE protein expressed in E. coli. The antisera were specific for HFE protein and the C282Y mutant in immunoblotting, immunoprecipitation and immunocytochemistry experiments of transfected cells, and they did not cross react with HLA antigens in various analyses. The antisera gave positive results in the staining of paraffin-fixed sections of duodenal slices of subjects with hemochromatosis. RESULTS: The antisera stained evident supranuclear granules in all enterocytes of 7 C282Y homozygous subjects, and a dark area in the same region in 3 other C282Y homozygotes. Granular bodies were absent from the duodenal sections of 8 C282Y negative subjects, from 2 C282Y heterozygotes and 3 C282Y homozygotes, with or without hemochromatosis. INTERPRETATION AND CONCLUSIONS: The detection of HFE-protein in granular bodies in the enterocytes of the large majority (77%) of C282Y homozygotes and not in other subjects suggests that the mutation facilitates protein accumulation in the duodenum.
Amino Acid Substitution↗
Caspase inhibition reveals functional cooperation between p55- and p75-TNF receptors in cell necrosis.
TNF-induced caspase activation is critically involved in both apoptosis and protection from cell necrosis. We have investigated the roles of the p55- and p75-TNF receptors (TNFR1 and TNFR2) in the induction of mouse L-M cell death in the presence of a caspase inhibitor (zVAD-fmk) and a transcription inhibitor (actinomycin D), i.e. under conditions in which protective pathways requiring caspase activation and protein synthesis were blocked. Cytometric analysis after TNF treatment showed that apoptosis was inhibited, while necrosis was highly activated. In contrast, apoptosis was observed in cells treated with TNF and actinomycin D alone. Stimulation of TNFR1 was sufficient to induce either cell necrosis or apoptosis, even when we blocked endogenous TNF with an anti-murine TNF antibody. Experiments based on the use of receptor-agonist and antagonist antibodies also showed that TNFR2 contributes to cell necrosis and apoptosis. Simultaneous stimulation of TNFR2 and TNFR1 with specific agonists indicated that TNFR2 functionally cooperates with TNFR1 to potentiate the response indirectly, by inducing endogenous TNF cytotoxicity. Caspase inhibitors enhanced the cytotoxic effect of endogenous TNF, suggesting that TNFR2 modulation can regulate the global necrotic response to TNF. TNFR2 modulation could play an important role in determining the response to TNF in pathophysiological conditions characterized by caspase down-regulation and local TNF production.
Amino Acid Chloromethyl Ketones↗
Overexpression of the hereditary hemochromatosis protein, HFE, in HeLa cells induces and iron-deficient phenotype.
A transfectant HeLa cell clone expressing HFE under the control of a tetracycline-repressible promoter was generated. HFE expression was fully repressed by the presence of doxycycline, while it was strongly induced by growth in the absence of doxycycline. HFE accumulation was accompanied by a large (approximately 10-fold) decrease in H- and L-ferritin levels, by a approximately 3-4-fold increase in transferrin receptor, and a approximately 2-fold increase in iron regulatory protein activity. These indices of cellular iron deficiency were reversed by iron supplementation complexes. The overexpressed HFE immunoprecipitated together with transferrin receptor, indicating a physical association which is the likely cause for the observed approximately 30% decrease in 55Fe-transferrin incorporation after 18 h incubation. In the HFE-expressing cells the reduction in transferrin-mediated iron incorporation was partially compensated by a approximately 30% increase in non-transferrin iron incorporation from 55Fe-NTA, evident after prolonged, 18 h, incubations. The findings indicate that HFE binding to transferrin receptor reduces cellular iron availability and regulates the balance between transferrin-mediated and non-transferrin-mediated cellular iron incorporation.
Apoferritins↗
Tumor pretargeting with avidin improves the therapeutic index of biotinylated tumor necrosis factor alpha in mouse models.
The clinical use of tumor necrosis factor alpha (TNF) as an anticancer drug is limited to local or locoregional administration because of dose-limiting systemic toxicity. We investigated in animal models whether the therapeutic index of systemically administered human or murine TNF can be increased by tumor pretargeting strategies based on the biotin-avidin system. Pretargeting of s.c. mouse WEHI-164 fibrosarcoma and RMA lymphoma genetically engineered to express the Thy 1.1 antigen on the cell membrane was achieved by i.p. injection of a biotinylated anti-Thy 1.1 antibody and avidin. This pretreatment increased the antitumor activity of systemically administered biotin-TNF conjugates by at least 5-fold. In contrast, pretargeting did not increase the toxicity of biotin-TNF, as judged by animal survival and weight loss after treatment. Ex vivo analysis of tumor cells 24 h after treatment showed that biotin-TNF persisted for several hours on the surface of pretargeted tumors, but not when avidin was omitted. The potentiation of the antitumor effects was related primarily to indirect mechanisms, involving a host-mediated response. The results indicate that tumor pretargeting improves the antitumor activity of TNF. Tumor pretargeting with avidin, which is currently used to increase the uptake of radioactive-labeled biotin in patients, could represent a new strategy for improving the therapeutic index of TNF.
Animals↗
Induction of therapeutic T-cell immunity by tumor targeting with soluble recombinant B7-immunoglobulin costimulatory molecules.
Tumor targeting with immunomodulatory molecules is an attractive strategy to enhance the host's antitumor response. Expression of CD80 (B7-1) and CD86 (B7-2) costimulatory molecules in tumor cells has proven to be an efficient way to enhance their immunogenicity. Here, we studied the effects of tumor targeting with biotinylated recombinant soluble B7-1- and B7-2 immunoglobulin G molecules (bio-B7-IgG) using a pretargeting approach based on the sequential use of a biotinylated antitumor monoclonal antibody and avidin. Mouse RMA T-lymphoma cells bearing either bio-B7-1-IgG or bio-B7-2-IgG on their surface prime in vitro naive CD8+ CTLs, which are highly effective in adoptive immunotherapy, and induce therapeutic immunity when injected in tumor-bearing animals. In vivo targeting of established RMA tumors with bio-B7-IgG either cures tumor-bearing mice or significantly prolongs their survival. The antitumor response induced by targeted bio-B7-IgG depends on both CD4+ and CD8+ T cells. Moreover, tumor targeting with bio-B7-IgG in vivo is critical for both expansion in lymphoid organs and mobilization into the tumor of tumor-specific CD8+ CTLs. When targeting is performed on poorly immunogenic TS/A mammary adenocarcinoma, only bio-B7-1-IgG primes naive CTLs in vitro and cures or significantly prolongs the survival of tumor-bearing mice in vivo, confirming that the two costimulatory molecules are not redundant with this tumor. Altogether, these data suggest that tumor avidination and targeting with soluble bio-B7-IgG may represent a promising strategy to enhance the antitumor response in the host.
Animals↗
Clusterin (SGP-2) gene expression is cell cycle dependent in normal human dermal fibroblasts.
In confluent human dermal fibroblasts brought to quiescence (G0) by serum starvation, the S phase peaked at 24 h after serum re-addiction and G2/M phase peaked at 36 h. This was confirmed by titration of h-gas1 mRNA (a marker of G0 phase) and histone H3 (a marker of S phase). Clusterin mRNA accumulation progressively increased in cells proceeding to confluence after seeding and to quiescence upon serum starvation, and peaked at around G0, in parallel with h-gas1 mRNA. At 6 h (roughly G1 phase) clusterin transcript formed a second peak, followed by a gradual decrease until 36 h. Correspondence of clusterin protein accumulation to its mRNA occurred solely with regard to the G0 peak but not to the second one. The possible meaning of the cell cycle related clusterin gene expression is discussed.
Blotting, Northern↗
Coordinate changes of polyamine metabolism regulatory proteins during the cell cycle of normal human dermal fibroblasts.
In human dermal fibroblasts, brought to quiescence (G0) by serum starvation, the S phase peaked 24 h and G2/M phases 36 h after serum re-addition. Under the same conditions, ornithine decarboxylase mRNA peaked at 12 h, decreased markedly in S phase and remained low until 48 h. Conversely, ornithine decarboxylase antizyme transcript dropped to its lowest level at 12 h, while reaching its highest values between 24 and 48 h. Ornithine decarboxylase activity followed essentially the pattern of its mRNA, but relative changes were much greater. S-Adenosylmethionine decarboxylase transcript and enzyme activity also peaked at around 12 h, decreasing thereafter. Spermidine/spermine N1-acetyltransferase mRNA and activity reached the highest values at 36-48 h. Putrescine concentration increased up to 18 h and fell dramatically in the S phase, remaining low thereafter. Both spermidine and spermine reached peaks at 18 h and decreased in the S phase, but not nearly as much as putrescine. We discuss how this comprehensive study may help to understand the involvement of polyamines in the control of cell proliferation.
Cell Cycle↗
Vascular attack and immunotherapy: a 'two hits' approach to improve biological treatment of cancer.
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Combined Modality Therapy↗
Induction of functional inducible nitric oxide synthase in monocytes of patients with congestive heart failure. Link with tumour necrosis factor-alpha.
AIMS: We studied the induction of monocytic inducible nitric oxide synthase expression and the tumour necrosis factor-alpha system in patients with congestive heart failure. METHODS AND RESULTS: Forty-three congestive heart failure patients and 15 healthy subjects were studied. Antigenic tumour necrosis factor-alpha and its soluble receptors, measured by ELISA, were increased in chronic heart failure and the increase was related to the clinical severity of the syndrome (tumour necrosis factor-alpha from 8.2+/-5.2 in NYHA class II to 18.2+/-7.2 in class III and 26.9+/-13.2 pg. ml(-1)in class IV, P<0.0001 classes III and IV vs class II; soluble tumour necrosis factor receptor I from 1.0+/-0.2 in class II to 2.3+/-1.1 in class III and 5.5+/-3.2 ng. ml(-1)in class IV, P<0.0001 classes III and IV vs class II; soluble tumour necrosis factor receptor II from 2.7+/-0.7 in class II to 4.9+/-1.9 in class III and 8.4+/-5.0 ng. ml(-1)in class IV, P<0.002 classes III and IV vs class II). Monocytic inducible nitric oxide synthase assessed by Western blot, was expressed only in congestive heart failure patients (13 out of 43). The association among monocytic inducible nitric oxide synthase expression, tumour necrosis factor-alpha system activation, neurohormones and other clinical parameters was studied. The univariate logistic regression showed that inducible nitric oxide synthase expression was strictly associated with NYHA class (P<0.05), antigenic tumour necrosis factor-alpha (P<0.01) and its soluble receptors (P<0.05). The multivariate analysis showed that antigenic tumour necrosis factor-alpha was the only predictor for monocytic inducible nitric oxide synthase expression (P<0.05, RR=2.75, CI 1. 34-5.43). CONCLUSIONS: Inducible nitric oxide synthase is expressed in circulating monocytes of patients with severe congestive heart failure. This phenomenon is linked to the activation of the tumour necrosis factor-alpha system.
Adult↗
Upregulation of p75 tumor necrosis factor alpha receptor in Mycobacterium avium-infected mice: evidence for a functional role.
The bacterial growth and the production of tumor necrosis factor alpha (TNF-alpha) and TNF receptors (TNF-Rs) in the spleen and blood of BALB/c mice challenged with Mycobacterium avium complex (MAC) were monitored. Infection developed in two phases: the first, up to day 21, was associated with rapid MAC multiplication in the spleen and a drop in the mycobacteremia, and the second was associated with control of the infection in both compartments. In the spleen, TNF-alpha and TNF-RII mRNA levels peaked on day 21 and then slowly decreased; however, no increase in the level of TNF-RI mRNA was observed throughout these experiments. The level of circulating soluble TNF-RII (sTNF-RII) was transiently increased after day 21. In a model in which overproduction of bioactive TNF-alpha was triggered in response to a second infection with MAC, an increased production of sTNF-RII by cultured splenocytes was also observed. Administration of an antagonist anti-TNF-RII monoclonal antibody (MAb 6G1) to infected mice inhibited the bacterial growth in the spleen, suggesting that the TNF-RII and/or sTNF-RII was functionally involved in the mechanisms that control the infection. Overall, these observations suggest that upregulation of TNF-RII or sTNF-RII contributes to modulation of the TNF-alpha antibacterial activity in MAC infections.
Animals↗
Biochemical characterization and crystal structure of a recombinant hen avidin and its acidic mutant expressed in Escherichia coli.
The mature hen avidin encoded by a synthetic cDNA was expressed in Escherichia coli in an insoluble form. After resolubilization, renaturation and purification, a recovery of about 20 mg/l cell culture was obtained. ELISA assays indicated no apparent differences in biotin binding between the natural and recombinant avidins. In addition, an acidic avidin mutant, bearing the substitutions Lys3-->Glu, Lys9--> Glu, Arg26-->Asp and Arg124-->Leu of four exposed basic residues, was produced. The protein, expressed and renatured as wild-type avidin, showed unaltered biotin-binding activity. The acidic pI (approximately 5.5) and lack of aggregation of the mutant allowed easy electrophoretic analysis under non-denaturing conditions of the protein alone and of its complexes with biotin, biotinylated transferrin or peroxidase. Analysis of the sera from sensitized subjects revealed that the avidin mutant has altered antigenicity. Both recombinant avidins were crystallized and the three-dimensional structures solved by molecular replacement and refined to 0.22 nm resolution. The three-dimensional structures of the two recombinant molecules, in the absence of biotin and of glycosylation, are fully comparable with those of the natural hen avidin previously reported.
Animals↗
Tumor targeting with biotinylated tumor necrosis factor alpha: structure-activity relationships and mechanism of action on avidin pretargeted tumor cells.
We have recently described a new strategy for targeting biotinylated tumor necrosis factor-alpha (TNF-alpha) to tumors, based on pretargeting with biotinylated antibodies and avidin. Here, we have analyzed the structure-activity relationships of several biotin-TNF-alpha conjugates and studied the mechanism of their interaction with avidin and TNF-alpha receptors on tumor cells. The study has been carried out using an in vitro model based on human melanoma Colo 38 cells and monoclonal antibody 225, an antibody against the high molecular weight melanoma-associated antigen. Immunochemical and cytotoxicity studies showed that biotin-TNF-alpha but not TNF-alpha persists for several hours on the surface of cells pretargeted with biotin-monoclonal antibody 225 and avidin and triggers cytolytic effects. Studies on the mechanism of action showed that biotin-TNF-alpha trimers can slowly dissociate from targeted cells in a bioactive form, through trimer-monomer-trimer transitions. Structure-activity relationship studies showed that nonbiotinylated subunits must be present in the biotin-TNF-alpha trimers for efficient release of bioactive TNF-alpha. Colo 38 cells targeted with biotin-TNF-alpha were able to kill mouse L-M cells in coculture experiments, indicating that the released TNF-alpha can interact also with TNF-alpha receptors expressed by bystander cells. In conclusion, the targeting complex works as a system that slowly releases bioactive TNF-alpha in the microenvironment of the targeted cell. This opens up the possibility that cells other than those reached by the targeting antibody (e.g., endothelial cells and local cells of the immune system) can be affected in vivo.
Animals↗
Chromogranin A induces a neurotoxic phenotype in brain microglial cells.
Chromogranin A (CGA) belongs to a multifunctional protein family widely distributed in secretory vesicles in neurons and neuroendocrine cells. Within the brain, CGA is localized in neurodegenerative areas associated with reactive microglia. By using cultured rodent microglia, we recently described that CGA induces an activated phenotype and the generation of nitric oxide. These findings led us to examine whether CGA might affect neuronal survival, expression of neurofilaments, and high affinity gamma-aminobutyric acid uptake in neurons cultured in the presence or absence of microglial cells. We found that CGA was unable to exert a direct toxic effect on neurons but provoked neuronal injury and degeneration in the presence of microglial cells. These effects were observed with natural and recombinant CGA and with a recombinant N-terminal fragment corresponding to residues 1-78. CGA stimulated microglial cells to secrete heat-stable diffusible neurotoxic agents. CGA also induced a marked accumulation of nitric oxide and tumor necrosis factor-alpha by microglia, but we could not establish a direct correlation between the levels of nitric oxide and tumor necrosis factor-alpha and the neuronal damage. The possibility that CGA represents an endogenous factor that triggers the microglial responses responsible for the pathogenesis of neuronal degeneration is discussed.
Animals↗
Hepatocellular carcinoma: comparison between liver transplantation, resective surgery, ethanol injection, and chemoembolization.
Between January 1989 and June 1997, 533 patients (423 male, 110 female, mean age 61 years, range 22-89 years) with hepatocellular carcinoma (HCC) were observed at our center. We report on 419 patients retrospectively compared for different treatments: liver transplantation (LT; 55 patients), resective surgery (RS; 41 patients), transarterial chemoembolization (TACE; 171 patients) and percutaneous ethanol injection (PEI; 152 patients). The 3- and 5-year actuarial survival rates were, respectively, 72% and 68% for LT, 64 and 44% for RS, 54 and 36% for PEI, and 32 and 22% for TACE. Survival curves were compared for sex, age, tumor characteristics, alphafetoprotein level, Child class, and etiology of cirrhosis. All patient-related characteristics examined (sex, age) are not significantly related to patient survival. Tumor-related variables and associated liver disease variables significantly conditioned survival in relation to different treatments. LT seems to be the treatment of choice for monofocal HCC less then 5 cm in diameter and in selected cases of plurifocal HCC.
Actuarial Analysis↗