ABSTRACT
Whole brain reirradiation for the treatment of multiple brain metastases has shown promising results. However, concerns remain over the possible neurotoxic effects of the cumulative dose as well as the questionable radiosensitivity of recurrent metastases. A second reirradiation of the whole brain is ordinarily performed in our department for palliative purposes in patients presenting with multiple metastatic brain progression. For this study, an investigational third whole brain reirradiation has been administered to highly selected patients to obtain disease control and delay progression. Clinical outcomes and neurological toxicity were also evaluated.
Subject(s)
Brain Neoplasms , Radiosurgery , Re-Irradiation , Humans , Brain Neoplasms/secondary , Cranial Irradiation/adverse effects , Cranial Irradiation/methods , Retrospective Studies , Brain , Radiosurgery/methodsABSTRACT
TRAP1 (Hsp75) is the mitochondrial paralog of the Hsp90 molecular chaperone family. Due to structural similarity among Hsp90 chaperones, a potential strategy to induce apoptosis through mitochondrial TRAP1 ATPase inhibition has been envisaged and a series of compounds has been developed by binding the simple pharmacophoric core of known Hsp90 inhibitors with various appendages bearing a permanent cationic head, or a basic group highly ionizable at physiologic pH. Cationic appendages were selected as vehicles to deliver drugs to mitochondria. Indeed, masses of new derivatives were evidenced to accumulate in the mitochondrial fraction from colon carcinoma cells and a compound in the series, with a guanidine appendage, demonstrated good activity in inhibiting recombinant TRAP1 ATPase and cell growth and in inducing apoptotic cell death in colon carcinoma cells.
Subject(s)
HSP90 Heat-Shock Proteins/antagonists & inhibitors , Isoxazoles/pharmacology , Mitochondria/metabolism , Adenosine Triphosphatases/antagonists & inhibitors , Apoptosis/drug effects , Cell Proliferation/drug effects , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Guanidines/chemical synthesis , Guanidines/chemistry , Guanidines/pharmacology , HCT116 Cells , Humans , Isoxazoles/chemical synthesis , Isoxazoles/chemistry , Molecular Structure , Onium Compounds/chemical synthesis , Onium Compounds/chemistry , Onium Compounds/pharmacology , Organophosphorus Compounds/chemical synthesis , Organophosphorus Compounds/chemistry , Organophosphorus Compounds/pharmacology , Pyridinium Compounds/chemical synthesis , Pyridinium Compounds/chemistry , Pyridinium Compounds/pharmacologyABSTRACT
Patients with hepatocellular carcinoma (HCC) comply with an advanced disease and are not eligible for radical therapy. In this distressed scenario new treatment options hold great promise; among them transarterial chemoembolization (TACE) and transarterial metabolic radiotherapy (TAMR) have shown efficacy in terms of both tumor shrinking and survival. External radiation therapy (RTx) by using novel three-dimensional conformal radiotherapy has also been used for HCC patients with encouraging results while its role had been limited in the past for the low tolerance of surrounding healthy liver. The rationale of TAMR derives from the idea of delivering exceptional radiation dose locally to the tumor, with cell killing intent, while preserving normal liver from undue exposition and minimizing systemic irradiation. Since the therapeutic efficacy of TACE is being continuously disputed, the TAMR with (131)I Lipiodol or (90)Y microspheres has gained consideration providing adequate therapeutic responses regardless of few toxicities. The implementation of novel radioisotopes and technological innovations in the field of RTx constitutes an intriguing field of research with important translational aspects. Moreover, the combination of different therapeutic approaches including chemotherapy offers captivating perspectives. We present the role of the radiation-based therapies in hepatocellular carcinoma patients who are not entitled for radical treatment.
Subject(s)
Carcinoma, Hepatocellular/therapy , Chemoembolization, Therapeutic/methods , Chemoradiotherapy/methods , Liver Neoplasms/therapy , Carcinoma, Hepatocellular/pathology , Humans , Liver/pathology , Liver Neoplasms/pathologyABSTRACT
Tumour cells have long been considered defective in mitochondrial respiration and mostly dependent on glycolytic metabolism. However, this assumption is currently challenged by several lines of evidence in a growing number of tumours. Ovarian cancer (OC) is one of the most lethal cancers worldwide, but it continues to be a poorly understood disease and its metabolic features are far to be elucidated. In this context, we investigated the role of tumour necrosis factor receptor-associated protein 1 (TRAP1), which is found upregulated in several cancer types and is a key modulator of tumour cell metabolism. Surprisingly, we found that TRAP1 expression inversely correlated with grade, stage and lower survival in a large cohort of OC patients. Accordingly, TRAP1 silencing induced resistance to cisplatin, resistant cells showed increased oxidative metabolism compared with their sensitive counterpart, and the bioenergetics cellular index of higher grade tumours indicated increased mitochondrial respiration. Strikingly, cisplatin resistance was reversible upon pharmacological inhibition of mitochondrial oxidative phosphorylation by metformin/oligomycin. At molecular level, increased oxidative metabolism in low TRAP1-expressing OC cells and tissues enhanced production of inflammatory mediators such as interleukin (IL)-6 and IL-8. Mechanistically, we identified members of the multidrug resistance complex (MDR) as key mediators of such metabolism-driven, inflammation-induced process. Indeed, treatment of OC cell lines with TNFα and IL6 induced a selective increase in the expression of TAP1 and multidrug resistance protein 1, whereas TAP1 silencing sensitized cells to cisplatin-induced apoptosis. Our results unveil a novel role for TRAP1 and oxidative metabolism in cancer progression and suggest the targeting of mitochondrial bioenergetics to increase cisplatin efficacy in human OC.
Subject(s)
Cisplatin/therapeutic use , Drug Resistance, Neoplasm , Inflammation/pathology , Ovarian Neoplasms/drug therapy , ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism , Cell Line, Tumor , Cell Survival/drug effects , Cisplatin/pharmacology , Disease-Free Survival , Female , Glycolysis , HSP90 Heat-Shock Proteins/antagonists & inhibitors , HSP90 Heat-Shock Proteins/genetics , HSP90 Heat-Shock Proteins/metabolism , Humans , Immediate-Early Proteins/genetics , Immediate-Early Proteins/metabolism , Inflammation/metabolism , Interleukin-6/genetics , Interleukin-6/metabolism , Interleukin-8/genetics , Interleukin-8/metabolism , Metformin/pharmacology , Ovarian Neoplasms/mortality , Ovarian Neoplasms/pathology , Oxidative Phosphorylation/drug effects , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , RNA Interference , RNA, Small Interfering/metabolismABSTRACT
TNF receptor-associated protein 1 (TRAP1), the main mitochondrial member of the heat shock protein (HSP) 90 family, is induced in most tumor types and is involved in the regulation of proteostasis in the mitochondria of tumor cells through the control of folding and stability of selective proteins, such as Cyclophilin D and Sorcin. Notably, we have recently demonstrated that TRAP1 also interacts with the regulatory protein particle TBP7 in the endoplasmic reticulum (ER), where it is involved in a further extra-mitochondrial quality control of nuclear-encoded mitochondrial proteins through the regulation of their ubiquitination/degradation. Here we show that TRAP1 is involved in the translational control of cancer cells through an attenuation of global protein synthesis, as evidenced by an inverse correlation between TRAP1 expression and ubiquitination/degradation of nascent stress-protective client proteins. This study demonstrates for the first time that TRAP1 is associated with ribosomes and with several translation factors in colon carcinoma cells and, remarkably, is found co-upregulated with some components of the translational apparatus (eIF4A, eIF4E, eEF1A and eEF1G) in human colorectal cancers, with potential new opportunities for therapeutic intervention in humans. Moreover, TRAP1 regulates the rate of protein synthesis through the eIF2α pathway either under basal conditions or under stress, favoring the activation of GCN2 and PERK kinases, with consequent phosphorylation of eIF2α and attenuation of cap-dependent translation. This enhances the synthesis of selective stress-responsive proteins, such as the transcription factor ATF4 and its downstream effectors BiP/Grp78, and the cystine antiporter system xCT, thereby providing protection against ER stress, oxidative damage and nutrient deprivation. Accordingly, TRAP1 silencing sensitizes cells to apoptosis induced by novel antitumoral drugs that inhibit cap-dependent translation, such as ribavirin or 4EGI-1, and reduces the ability of cells to migrate through the pores of transwell filters. These new findings target the TRAP1 network in the development of novel anti-cancer strategies.
Subject(s)
Colorectal Neoplasms/metabolism , Colorectal Neoplasms/pathology , Heat-Shock Proteins/metabolism , Protein Biosynthesis , Stress, Physiological , TNF Receptor-Associated Factor 1/metabolism , Colorectal Neoplasms/genetics , Down-Regulation , Endoplasmic Reticulum Chaperone BiP , Eukaryotic Initiation Factor-2/metabolism , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , HCT116 Cells , Humans , Neoplasms/metabolism , Neoplasms/pathology , Protein Binding , Proteolysis , Ribosomes/metabolism , Signal Transduction , UbiquitinationABSTRACT
Tumor necrosis factor receptor-associated protein-1 (TRAP1) is a mitochondrial (MITO) antiapoptotic heat-shock protein. The information available on the TRAP1 pathway describes just a few well-characterized functions of this protein in mitochondria. However, our group's use of mass-spectrometric analysis identified TBP7, an AAA-ATPase of the 19S proteasomal subunit, as a putative TRAP1-interacting protein. Surprisingly, TRAP1 and TBP7 colocalize in the endoplasmic reticulum (ER), as demonstrated by biochemical and confocal/electron microscopic analyses, and interact directly, as confirmed by fluorescence resonance energy transfer analysis. This is the first demonstration of TRAP1's presence in this cellular compartment. TRAP1 silencing by short-hairpin RNAs, in cells exposed to thapsigargin-induced ER stress, correlates with upregulation of BiP/Grp78, thus suggesting a role of TRAP1 in the refolding of damaged proteins and in ER stress protection. Consistently, TRAP1 and/or TBP7 interference enhanced stress-induced cell death and increased intracellular protein ubiquitination. These experiments led us to hypothesize an involvement of TRAP1 in protein quality control for mistargeted/misfolded mitochondria-destined proteins, through interaction with the regulatory proteasome protein TBP7. Remarkably, expression of specific MITO proteins decreased upon TRAP1 interference as a consequence of increased ubiquitination. The proposed TRAP1 network has an impact in vivo, as it is conserved in human colorectal cancers, is controlled by ER-localized TRAP1 interacting with TBP7 and provides a novel model of the ER-mitochondria crosstalk.
Subject(s)
Colorectal Neoplasms/metabolism , Endoplasmic Reticulum Stress , Endoplasmic Reticulum/metabolism , HSP90 Heat-Shock Proteins/metabolism , Mitochondrial Proteins/metabolism , Neoplasm Proteins/metabolism , Proteasome Endopeptidase Complex/metabolism , Ubiquitination , ATPases Associated with Diverse Cellular Activities , Cell Line, Tumor , Colorectal Neoplasms/genetics , Colorectal Neoplasms/pathology , Endoplasmic Reticulum/genetics , Endoplasmic Reticulum/pathology , Endoplasmic Reticulum Chaperone BiP , Gene Silencing , HSP90 Heat-Shock Proteins/genetics , Humans , Mitochondrial Proteins/genetics , Neoplasm Proteins/genetics , Proteasome Endopeptidase Complex/genetics , Protein FoldingABSTRACT
BACKGROUND: Non-invasive ventilation (NIV) is increasingly utilized for patients with acute respiratory failure (ARF). The shortage of Intensive Care Unit (ICU) beds, a growing confidence with the technique, and the opportunity to treat ARF in a more responsive phase lead to the application of NIV outside of the ICU. The Study Group on Emergency of the Italian Society of Anesthesia, Analgesia, Resuscitation and Intensive Care (SIAARTI) promoted a national survey to collect data on NIV use outside of the ICU. METHODS: An anonymous questionnaire was developed, focusing on the location and modalities of NIV treatments, organizational and technical aspects, monitoring, estimated outcomes, the presence of protocols, and complications. The questionnaire was mailed to all members of the Scientific Society. RESULTS: Forty-six respondents were from 46 hospitals. Thirty-seven (80%) respondents applied NIV in the Emergency Department and/or General Wards. In the majority of hospitals (72%), training preceded NIV introduction. NIV could be applied in all ordinary wards in 28% of the hospitals. Patients remained in their ward in 89% of the hospitals, and a protocol was present in 70% of the hospitals. Monitoring was usually limited to continuous pulse-oxymetry and EKG; 18% of respondents did not have a monitoring standard. Reported complications and practical problems were potentially severe. Few hospitals (15%) collected data on NIV treatments. The efficacy of NIV was perceived as low, as 73% of respondents estimated that NIV avoided tracheal intubation in less than half of the treated patients. CONCLUSION: In Italy, NIV is extensively applied in non-intensive wards, and its use is not free from criticalities and contradictions. Further prospective studies and possibly guidelines are needed.
Subject(s)
Respiration, Artificial/statistics & numerical data , Contraindications , Critical Care , Electrocardiography , Health Care Surveys , Hospitals/statistics & numerical data , Humans , Italy , Monitoring, Physiologic , Oximetry , Respiration, Artificial/adverse effects , Respiratory Insufficiency/etiology , Respiratory Insufficiency/therapy , Surveys and QuestionnairesABSTRACT
An unknown primary tumor (UPT) is defined by the presence of a metastatic cancer without a known primary site of origin despite a standardized diagnostic workup. Clinically, UPTs show rapid progression and early dissemination, with signs and symptoms related to the metastatic site. The molecular bases of their biology remain largely unknown, with no evidence as to whether they represent a distinct biological entity. Immunohistochemistry remain the best diagnostic tool in term of cost-effectiveness, but the time-consuming "algorithmic process" it relies on has led to the application of new molecular techniques for the identification of the primary site of UPTs. For example, several microarray or miRNA classifications of UPTs have been used, with an accuracy in the prediction of the primary site as high as 90%. It should be noted that validating a prediction of tissue origin is challenging in these patients, since most of them will never have a primary site identified. Moreover, prospective studies to determine whether selection of treatment options based on such profiling methods actually improves patient outcome are still missing. In the last few years functional imaging (i.e. FDG-PET/CT) has gained a main role in the detection of the site of origin of UPTs and is currently recommended by the European Association of Nuclear Medicine. However, despite recent refinements in the diagnostic workup, the site of origin of UPT often remains elusive. As a consequence, treatment of patients with UPT is still empirical and inadequate.
Subject(s)
Neoplasms, Unknown Primary/genetics , Animals , Gene Expression Profiling , Humans , MicroRNAs/analysis , Neoplasms, Unknown Primary/diagnosis , Neoplasms, Unknown Primary/pathology , Neoplasms, Unknown Primary/therapyABSTRACT
TRAP-1 is a mitochondrial heat shock protein (HSP), recently identified in Saos-2 osteosarcoma cells adapted to mild oxidative stress induced by diethylmaleate (DEM). TRAP-1 mRNA expression is increased in DEM-adapted cells as well as in tumor cells resistant to 5-fluorouracil and to platin derivatives. Since a strong decrease of TRAP-1 protein levels, upon cisplatin treatment, is observed only in controls but not in the DEM-adapted counterpart, a possible role for this protein in the development of resistant phenotypes could be hypothesized. To characterize the protective role of TRAP-1 against oxidative stress and apoptosis, stable transfectants were generated and characterized for their response to different stress types. These stable clones expressing constitutively high TRAP-1 levels: (i) are more resistant to H2O2-induced DNA damage and to apoptosis by cisplatin; (ii) contain higher reduced glutathione (GSH) levels than control cells; and (iii) do not release the apoptosis-inducing factor into the nucleus upon cisplatin treatment. Furthermore, high TRAP-1 levels interfere with caspase 3 activation. These results confirm the anti-apoptotic role of TRAP-1, and suggest that increased expression of this mitochondrial HSP in DEM-adapted and chemoresistant cells could be part of a pro-survival signaling pathway aimed to evade toxic effects of oxidants and anticancer drugs.
Subject(s)
Apoptosis , HSP90 Heat-Shock Proteins/physiology , Oxidative Stress , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Cell Nucleus/metabolism , Cisplatin/pharmacology , Comet Assay , Drug Resistance, Neoplasm , HSP90 Heat-Shock Proteins/metabolism , Humans , Hydrogen Peroxide/pharmacology , Mitochondrial Proteins/metabolism , Models, Biological , Osteosarcoma/pathology , Reactive Oxygen Species , Tetrazolium Salts/pharmacology , Thiazoles/pharmacologyABSTRACT
Several schedules of 5-fluorouracil (FU) and irinotecan (IRI) have been shown to improve overall survival in advanced colorectal cancer (CRC). Preclinical evidence suggests that the sequential administration of IRI and FU produces synergistic activity, although their clinical use has not been fully optimised. We investigated the interaction between short-term exposure to SN-38, the active metabolite of IRI, and prolonged exposure to FU in human CRC HT-29 cells and observed that the synergism of action between the two agents can be increased by extending the time of cell exposure to FU and reducing the interval between administration of the two agents. Based on these findings, we performed a phase I trial in 25 advanced CRC patients using a modified IRI/FU regimen as first-line therapy and evaluated three dose levels of IRI (150-300 mg/m(2)) and two of continuous infusion of FU (800-1000 mg/m(2)) in a 3-weekly schedule. The most severe grade III-IV toxicities were neutropoenia in four cycles and diarrhoea in three. One patient achieved complete response (4%), 12 a partial response (48%), the overall response rate was 52% (+/-20, 95% CI); seven of 25 patients had stable disease (28%), the overall disease control was 80% (+/-16, 95% CI). This modified IRI/FU schedule is feasible and exhibits potentially interesting clinical activity.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Camptothecin/analogs & derivatives , Colorectal Neoplasms/drug therapy , Fluorouracil/administration & dosage , Adult , Aged , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Apoptosis/drug effects , Camptothecin/administration & dosage , Camptothecin/adverse effects , Camptothecin/pharmacology , Cell Cycle/drug effects , Cell Proliferation/drug effects , Chemotherapy, Adjuvant , Cohort Studies , Disease Progression , Dose-Response Relationship, Drug , Drug Administration Schedule , Drug Synergism , Feasibility Studies , Female , Fluorouracil/adverse effects , Fluorouracil/pharmacology , HT29 Cells , Humans , Infusions, Intravenous , Irinotecan , Male , Maximum Tolerated Dose , Middle Aged , Recurrence , Treatment OutcomeABSTRACT
S100 proteins are Ca(2+)-binding polypeptides involved in the tumourigenesis of several human neoplasms. S100A13 is a key regulator of the stress-dependent release of FGF1, the prototype of the FGF protein family involved in angiogenesis. Indeed, S100A13 is a copper binding protein able to enhance the export of FGF1 in response to stress in vitro and to induce the formation of a multiprotein aggregate responsible for FGF1 release. We investigated the expression of S100A13 in human astrocytic gliomas in relation to tumour grading and vascularization. A series of 26 astrocytic gliomas was studied to evaluate microvessel density and to assess FGF1, S100A13 and VEGF-A expression. FGF1 was equally expressed in the vast majority of tumours, whereas S100A13 and VEGF-A were significantly up-regulated in high-grade vascularized gliomas. Moreover, both S100A13 and VEGF-A expression significantly correlated with microvessel density and tumour grading. These data suggest that the up-regulation of S100A13 and VEGF-A expression correlates with the activation of angiogenesis in high-grade human astrocytic gliomas.
Subject(s)
Astrocytoma/blood supply , Biomarkers, Tumor/metabolism , Brain Neoplasms/blood supply , Neovascularization, Pathologic/metabolism , S100 Proteins/metabolism , Vascular Endothelial Growth Factor A/metabolism , Adult , Aged , Astrocytoma/metabolism , Brain Neoplasms/metabolism , Female , Fibroblast Growth Factors/metabolism , Humans , Male , Middle Aged , Severity of Illness Index , Statistics, Nonparametric , Up-RegulationABSTRACT
This study was conceived to assess a pattern of Italian prehospital critical care team, especially referring to the advanced life support (ALS) rescue team. Function and management of ALS rescue team and its relationship with other members of the emergency medical system (intra hospital physician, basic life support team, general practitioner) are analysed; stress is laidon the knowledge, the background and the complexity of the emergency procedures. The benefit of 2 major prehospital options of the ALS team, composed by 1 physician and 1 nurse staffing or by 2 trained nurse staffing, is discussed; the importance of educational programs for ambulance teams, a comparison of cost-effectiveness and the number of emergency teams availability is underlined. The authors, finally emphasize the advantages of a territorial coverage with an integrated system of ambulances staffed with specially trained rescuers or technicians, ambulances with rescuers and nurses, and ALS teams staffed with emergency physician and 1 nurse (integrated or not with ambulances with 2 trained nurses), being perfectly capable to face up any background in pre-hospital emergency medicine setting.
Subject(s)
Emergency Medical Services , Emergency Nursing , Emergency Treatment , Humans , Nurses , PhysiciansABSTRACT
BACKGROUND: The aim of this research is to evaluate quality of out-of-hospital medical services in our country, using performance indicators and a new computerised database. METHODS: (a) EXPERIMENTAL DESIGN: Data were collected prospectively in three emergency dispatch centres for 90 days. Follow-up was evaluated at 1 day and 1 month after the event. This paper presents data on the cardiac arrest cohort only. (b) SETTING: Three emergency dispatch centres in Lombardia. (c) PATIENTS: One hundred and seventy-eight patients in non-traumatic cardiac arrest were enrolled. (d) INTERVENTIONS: None. The study was observational only. RESULTS: Mean interval between phone call and arrival on scene was 8.5+/-3.5 min. BLS manoeuvres were carried out from bystanders only in 15% of the cohort; this was associated with significant mortality reduction (85.7 versus 95.8%, chi(2) P<0.05). One hundred and thirty-three patients (75%) received assistance from BLS crews while only 45 patients (25%) were assisted by ALS medical personel, with a significant mortality reduction (ALS deaths 86.7%, BLS deaths 97%). Total 24 h survival was 9% and survival at 1 month declined to 6.17%. CONCLUSIONS: Quality monitoring produces objective information on interventions and outcomes. Only with this information, is it possible to implement improvement programmes that are planned according to the data presented.
Subject(s)
Cardiopulmonary Resuscitation/standards , Emergency Medical Services/standards , Heart Arrest/therapy , Outcome Assessment, Health Care , Aged , Aged, 80 and over , Emergency Medical Service Communication Systems , Female , Heart Arrest/mortality , Humans , Italy/epidemiology , Male , Prospective Studies , Quality of Health Care , Survival RateABSTRACT
The signal peptide-less FGF gene family prototype, FGF1 is released in response to temperature stress in vitro as a latent reducing agent-sensitive homodimer non-covalently complexed with the extravesicular p40 domain of p65 synaptotagmin (Syt)1. Because FGF1 is well recognized as an angiogenesis factor in vivo and angiogenesis is known to be induced by hypoxia, we examined the release of FGF1 and p40 Syt1 under conditions of hypoxia and temperature stress using a chemostatic microcarrier cell culture system. We report that like the pathway used by FGF1 and p40 Syt1 release under temperature stress, hypoxia also induces the release of FGF1 and p40 Syt1 with similar kinetic and pharmacologic properties including the requirement for functional cysteine residues. Lastly, FGF1 and p40 Syt1 release in response to hypoxia and temperature stress is sensitive to lipoxygenase and cyclooxygenase inhibitors suggesting that arachidonic acid metabolism may play an important role in the mechanism of FGF1 release in vitro.
Subject(s)
Calcium-Binding Proteins , Cell Hypoxia/physiology , Fibroblast Growth Factor 1/metabolism , 3T3 Cells , 5,8,11,14-Eicosatetraynoic Acid/pharmacology , Aminopyridines/pharmacology , Animals , Arachidonic Acid/metabolism , Cell Line , Cyclooxygenase Inhibitors/pharmacology , Cysteine/chemistry , Dimerization , Fibroblast Growth Factor 1/chemistry , Fibroblast Growth Factor 1/genetics , Humans , Lipoxygenase Inhibitors/pharmacology , Macromolecular Substances , Membrane Glycoproteins/chemistry , Membrane Glycoproteins/metabolism , Mice , Nerve Tissue Proteins/chemistry , Nerve Tissue Proteins/metabolism , Nitrobenzenes/pharmacology , Stress, Physiological/physiopathology , Sulfonamides/pharmacology , Synaptotagmin I , Synaptotagmins , Temperature , TransfectionABSTRACT
Fibroblast growth factor (FGF) 1 is known to be released in response to stress conditions as a component of a multiprotein aggregate containing the p40 extravescicular domain of p65 synaptotagmin (Syt) 1 and S100A13. Since FGF1 is a Cu2+-binding protein and Cu2+ is known to induce its dimerization, we evaluated the capacity of recombinant FGF1, p40 Syt1, and S100A13 to interact in a cell-free system and the role of Cu2+ in this interaction. We report that FGF1, p40 Syt1, and S100A13 are able to bind Cu2+ with similar affinity and to interact in the presence of Cu2+ to form a multiprotein aggregate which is resistant to low concentrations of SDS and sensitive to reducing conditions and ultracentrifugation. The formation of this aggregate in the presence of Cu2+ is dependent on the presence of S100A13 and is mediated by cysteine-independent interactions between S100A13 and either FGF1 or p40 Syt1. Interestingly, S100A13 is also able to interact in the presence of Cu2+ with Cys-free FGF1 and this observation may account for the ability of S100A13 to export Cys-free FGF1 in response to stress. Lastly, tetrathiomolybdate, a Cu2+ chelator, significantly represses in a dose-dependent manner the heat shock-induced release of FGF1 and S100A13. These data suggest that S100A13 may be involved in the assembly of the multiprotein aggregate required for the release of FGF1 and that Cu2+ oxidation may be an essential post-translational intracellular modifier of this process.
Subject(s)
Copper/pharmacology , Fibroblast Growth Factor 2/metabolism , S100 Proteins/metabolism , Stress, Physiological/metabolism , Animals , Cell-Free System , Cysteine/metabolism , Detergents/pharmacology , Dimerization , Fibroblast Growth Factor 1 , Humans , Molybdenum/pharmacology , Nerve Tissue Proteins/metabolism , Oxidation-Reduction , Peptide Fragments/metabolism , Rabbits , Sodium Dodecyl Sulfate/pharmacology , Synaptotagmin IABSTRACT
We have previously demonstrated that the expression of the soluble extracellular domain of the transmembrane ligand for Notch receptors, Jagged 1 (sJ1), in NIH 3T3 cells results in the formation of a matrix-dependent chord-like phenotype, the loss of contact inhibition of growth, and an inhibition of pro-alpha 1(I) collagen expression. In an effort to define the mechanism by which sJ1 induces this phenotype, we report that sJ1 transfectants display biochemical and cytoskeletal alterations consistent with the activation of Src. Indeed, cotransfection of sJ1 transfectants with a dominant-negative mutant of Src resulted in the loss of matrix-dependent chord formation and correlated with the restoration of type I collagen expression and contact inhibition of growth. We also report that the sJ1-mediated induction of Src activity and related phenotypes, including chord formation, may result from the inhibition of endogenous Jagged 1-mediated Notch signaling since it was not possible to detect an sJ1-dependent induction of CSL-dependent transcription in these cells. Interestingly, NIH 3T3 cells transfected with dominant-negative (but not constitutively active) mutants of either Notch 1 or Notch 2 displayed a similar Src-related phenotype as the sJ1 transfectants. These data suggest that the ability of sJ1 to mediate chord formation is Src-dependent and requires the repression of endogenous Jagged 1-mediated Notch signaling, which is tolerant to the destabilization of the actin cytoskeleton, a mediator of cell migration.
Subject(s)
Membrane Proteins/physiology , Oncogene Protein pp60(v-src)/metabolism , Proteins/physiology , 3T3 Cells , Animals , Calcium-Binding Proteins , Cortactin , Intercellular Signaling Peptides and Proteins , Jagged-1 Protein , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mice , Microfilament Proteins/metabolism , Mutagenesis, Site-Directed , Phenotype , Phosphorylation , Proteins/genetics , Proteins/metabolism , Receptors, Notch , Serrate-Jagged Proteins , Spectrometry, Fluorescence , Transfection , Tyrosine/metabolismABSTRACT
S100A13, a member of the S100 gene family of Ca(2+)-binding proteins has been previously characterized as a component of a brain-derived heparin-binding multiprotein aggregate/complex containing fibroblast growth factor 1 (FGF1). We report that while expression of S100A13 in NIH 3T3 cells results in the constitutive release of S100A13 into the extracellular compartment at 37 degrees C, co-expression of S100A13 with FGF1 represses the constitutive release of S100A13 and enables NIH 3T3 cells to release S100A13 in response to temperature stress. S100A13 release in response to stress occurs with kinetics similar to that observed for the stress-induced release of FGF1, but S100A13 expression is able to reverse the sensitivity of FGF1 release to inhibitors of transcription and translation. The release of FGF1 and S100A13 in response to heat shock results in the solubility of FGF1 at 100% (w/v) ammonium sulfate saturation, and the expression of a S100A13 deletion mutant lacking its novel basic residue-rich domain acts as a dominant negative effector of FGF1 release in vitro. Surprisingly, the expression of S100A13 also results in the stress-induced release of a Cys-free FGF1 mutant, which is normally not released from NIH 3T3 cells in response to heat shock. These data suggest that S100A13 may be a component of the pathway for the release of the signal peptide-less polypeptide, FGF1, and may involve a role for S100A13 in the formation of a noncovalent FGF1 homodimer.
Subject(s)
Calcium-Binding Proteins/physiology , Fibroblast Growth Factor 2/metabolism , Heat-Shock Response , S100 Proteins , 3T3 Cells , Animals , Fibroblast Growth Factor 1 , Heparin/metabolism , Mice , Protein Biosynthesis , Sheep , Transcription, GeneticABSTRACT
We address the issue of the role of manganese superoxide dismutase in tumorigenesis by studying a relatively homogeneous group of tumours for the correlation between amount of this anti-oxidant enzyme and prognosis. The clinical outcome of 30 patients affected by glioblastomas whose manganese superoxide dismutase content had been established at the time of first diagnosis is compared. When the survival of patients is stratified according to manganese superoxide dismutase level in the tumour, a link of these levels and prognosis can be observed. Patients with high levels of manganese superoxide dismutase show a median survival time of 6.11 months, while patients whose tumours display a low amount of MnSOD have a median survival time of 12.17 months. To assess the upstream mechanisms that sustain the increase in manganese superoxide dismutase content in brain neuroepithelial tumours, we also studied the expression of p53 in a series of 17 astrocytomas of various grading. In all tested astrocytomas, high manganese superoxide dismutase content is associated with cytoplasmic accumulation of p53. Thus glioblastomas can be divided into two distinct groups on the basis of their content of manganese superoxide dismutase, having 'better' or 'worse' prognosis, respectively. The use of this protein as a marker may help to define therapeutic strategies in the clinical management of glioblastoma.
Subject(s)
Astrocytoma/enzymology , Biomarkers, Tumor/analysis , Brain Neoplasms/enzymology , Glioblastoma/enzymology , Superoxide Dismutase/analysis , Adult , Aged , Astrocytoma/pathology , Brain Neoplasms/pathology , Female , Follow-Up Studies , Genes, p53/genetics , Glioblastoma/pathology , Humans , Male , Middle Aged , Neoplasm Staging/methods , Prognosis , Survival AnalysisABSTRACT
Interleukin (IL)1alpha mediates proinflammatory events through its extracellular interaction with the IL1 type I receptor. However, IL1alpha does not contain a conventional signal peptide sequence that provides access to the endoplasmic reticulum-Golgi apparatus for secretion. Thus, we have studied the release of the precursor (p) and mature (m) forms of IL1alpha from NIH 3T3 cells. We have demonstrated that mIL1alpha but not pIL1alpha was released in response to heat shock with biochemical and pharmacological properties similar to those reported for the stress-mediated release pathway utilized by fibroblast growth factor (FGF)1. However, unlike the FGF1 release pathway, the IL1alpha release pathway appears to function independently of synaptotagmin (Syt)1 because the expression of a dominant-negative form of Syt1, which represses the release of FGF1, did not inhibit the release of mIL1alpha in response to temperature stress. Interestingly, whereas the expression of both mIL1alpha and FGF1 in NIH 3T3 cells did not impair the stress-induced release of either polypeptide, the expression of both pIL1alpha and FGF1 repressed the release of FGF1 in response to temperature stress. These data suggest that the release of mIL1alpha requires proteolytic processing of its precursor form and that mIL1alpha and FGF1 may utilize similar but distinct mechanisms for export.