Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 350
Filter
2.
ESMO Open ; 6(3): 100103, 2021 06.
Article in English | MEDLINE | ID: mdl-33887686

ABSTRACT

BACKGROUND: Organoid technology has recently emerged as a powerful tool to assess drug sensitivity of individual patient tumors in vitro. Organoids may therefore represent a new avenue for precision medicine, as this circumvents many of the complexities associated with DNA- or transcriptional-profiling. MATERIALS AND METHODS: The SENSOR trial was a single-arm, single-center, prospective intervention trial to evaluate the feasibility of patient-derived organoids to allocate patients for treatment with off-label or investigational agents. The primary endpoint was an objective response rate of ≥20%. Patients underwent a biopsy for culture before commencing their last round standard of care. Organoids were exposed to a panel of eight drugs and patients were treated after progression on standard-of-care treatment and when a clear signal of antitumor activity was identified in vitro. RESULTS: Sixty-one patients were included and we generated 31 organoids of 54 eligible patients. Twenty-five cultures were subjected to drug screening and 19 organoids exhibited substantial responses to one or more drugs. Three patients underwent treatment with vistusertib and three with capivasertib. Despite drug sensitivity of organoids, patients did not demonstrate objective clinical responses to the recommended treatment. CONCLUSIONS: Organoid technology had limited value as a tool for precision medicine in this patient population because a large fraction of patients could not undergo treatment or because the recommended treatment did not elicit an objective response. We identified several essential parameters, such as the culture success rate, clinical deterioration of patients during standard of care, and rational design of drug panels that need to be accounted for in organoid-guided clinical studies.


Subject(s)
Colorectal Neoplasms , Pharmaceutical Preparations , Colorectal Neoplasms/drug therapy , Humans , Organoids , Precision Medicine , Prospective Studies
3.
Eur J Cancer ; 136: 132-139, 2020 09.
Article in English | MEDLINE | ID: mdl-32683273

ABSTRACT

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2, has inevitable consequences for medical care of patients without COVID-19. To assess the impact of this pandemic on oncological care, a nationwide survey was conducted among patients with cancer in the Netherlands. METHODS: The patients' perspective on oncological care was investigated using an online survey between March 29th 2020 and April 18th 2020. The survey consisted of 20 questions on four topics: patients' characteristics, contact with the hospital, consequences of the COVID-19 pandemic and concerns about COVID-19. RESULTS: Five thousand three hundred two patients with cancer completed this nationwide survey. Overall, 30% of patients reported consequences for their oncological treatment or follow-up. In the majority of cases, this resulted in conversion from hospital visit to consultation by phone or video. The most frequently adjusted treatments were chemotherapy (30%) and immunotherapy (32%). Among patients with delay and discontinuation of treatment, 55% and 63% of patients, respectively, were (very) concerned about these consequences of the COVID-19 pandemic. Consequences were independent of regional differences in COVID-19 incidence. However, patients in regions with high COVID-19 incidence were significantly more concerned. CONCLUSION: This is the first study investigating perspectives of patients with cancer during the COVID-19 pandemic. The study demonstrates the significant impact of the COVID-19 crisis on oncological care, indicating the need for psycho-oncological support during this pandemic.


Subject(s)
Antineoplastic Agents/therapeutic use , Attitude to Health , Coronavirus Infections/epidemiology , Neoplasms/therapy , Pneumonia, Viral/epidemiology , Telemedicine , Time-to-Treatment , Aged , Betacoronavirus , COVID-19 , Female , Humans , Immunotherapy , Incidence , Male , Medical Oncology , Middle Aged , Neoplasms/psychology , Netherlands/epidemiology , Pandemics , Psycho-Oncology , SARS-CoV-2 , Surveys and Questionnaires
4.
Acta Oncol ; 57(2): 195-202, 2018 Feb.
Article in English | MEDLINE | ID: mdl-28723307

ABSTRACT

BACKGROUND: The increasing sub-classification of cancer patients due to more detailed molecular classification of tumors, and limitations of current trial designs, require innovative research designs. We present the design, governance and current standing of three comprehensive nationwide cohorts including pancreatic, esophageal/gastric, and colorectal cancer patients (NCT02070146). Multidisciplinary collection of clinical data, tumor tissue, blood samples, and patient-reported outcome (PRO) measures with a nationwide coverage, provides the infrastructure for future and novel trial designs and facilitates research to improve outcomes of gastrointestinal cancer patients. MATERIAL AND METHODS: All patients aged ≥18 years with pancreatic, esophageal/gastric or colorectal cancer are eligible. Patients provide informed consent for: (1) reuse of clinical data; (2) biobanking of primary tumor tissue; (3) collection of blood samples; (4) to be informed about relevant newly identified genomic aberrations; (5) collection of longitudinal PROs; and (6) to receive information on new interventional studies and possible participation in cohort multiple randomized controlled trials (cmRCT) in the future. RESULTS: In 2015, clinical data of 21,758 newly diagnosed patients were collected in the Netherlands Cancer Registry. Additional clinical data on the surgical procedures were registered in surgical audits for 13,845 patients. Within the first two years, tumor tissue and blood samples were obtained from 1507 patients; during this period, 1180 patients were included in the PRO registry. Response rate for PROs was 90%. The consent rate to receive information on new interventional studies and possible participation in cmRCTs in the future was >85%. The number of hospitals participating in the cohorts is steadily increasing. CONCLUSION: A comprehensive nationwide multidisciplinary gastrointestinal cancer cohort is feasible and surpasses the limitations of classical study designs. With this initiative, novel and innovative studies can be performed in an efficient, safe, and comprehensive setting.


Subject(s)
Gastrointestinal Neoplasms , Observational Studies as Topic/methods , Randomized Controlled Trials as Topic/methods , Research Design , Biological Specimen Banks , Cohort Studies , Humans , Registries
5.
Ann Oncol ; 28(8): 1842-1848, 2017 Aug 01.
Article in English | MEDLINE | ID: mdl-28481967

ABSTRACT

BACKGROUND: In the open-label randomized phase III AURELIA trial, adding bevacizumab to chemotherapy for platinum-resistant ovarian cancer (PROC) significantly improved progression-free survival and response rate versus chemotherapy alone, but not overall survival (OS). We explored the effect of bevacizumab use after disease progression (PD) in patients randomized to chemotherapy alone. PATIENTS AND METHODS: In AURELIA, 361 women with PROC were randomized to chemotherapy alone or with bevacizumab. Patients initially randomized to chemotherapy were offered bevacizumab after PD. Post hoc analyses assessed efficacy and safety in three subgroups: chemotherapy alone, chemotherapy followed by bevacizumab after PD, and chemotherapy plus bevacizumab at randomization. RESULTS: Of the 182 patients randomized to chemotherapy alone, 72 (40%) received bevacizumab after PD and 110 (60%) never received bevacizumab. There were no significant differences in patient and disease characteristics between these subgroups at baseline or the time of PD. Compared with patients never receiving bevacizumab, the risk of death was significantly reduced in patients receiving bevacizumab either upfront with chemotherapy [hazard ratio (HR) = 0.68, 95% confidence interval (CI) 0.52-0.90] or after PD (HR = 0.60, 95% CI 0.43-0.86). The tolerability of bevacizumab was similar with administration upfront or after PD. CONCLUSIONS: Post-PD bevacizumab use may have confounded OS results in AURELIA. In these exploratory analyses of non-randomized subgroups, bevacizumab use, either with chemotherapy or after PD on chemotherapy alone, improved OS compared with no bevacizumab. Combining bevacizumab with chemotherapy at first appearance of platinum resistance maximises the likelihood of patients receiving this active treatment for PROC. ClinicalTrials.gov: NCT00976911.


Subject(s)
Antineoplastic Agents, Immunological/therapeutic use , Bevacizumab/therapeutic use , Ovarian Neoplasms/drug therapy , Antineoplastic Agents, Immunological/adverse effects , Bevacizumab/adverse effects , Disease Progression , Drug Resistance, Neoplasm , Female , Humans , Organoplatinum Compounds/therapeutic use , Ovarian Neoplasms/pathology , Survival Analysis
6.
Br J Cancer ; 116(10): 1312-1317, 2017 May 09.
Article in English | MEDLINE | ID: mdl-28399110

ABSTRACT

BACKGROUND: Cabazitaxel is approved for treatment of castration-resistant metastatic prostate cancer. The current dosing strategy of cabazitaxel is based on body surface area (BSA). Body surface area is known as a poor predictor for total systemic exposure to drugs, since it does not take into account variability in activity of metabolising enzymes, necessary for clearance of drugs. As exposure to cabazitaxel is related to treatment response, it is essential to develop a better individualised dosing strategy. METHODS: Ten patients with metastatic castration-resistant prostate cancer, who received cabazitaxel dosed on BSA as a part of routine palliative care, were enrolled in this study. Midazolam was administered as phenotyping probe for cytochrome P450 isoenzyme 3A (CYP3A). The relationship between midazolam and cabazitaxel clearance was investigated using non-linear mixed effects modelling. RESULTS: The clearance of Midazolam highly correlated with cabazitaxel clearance (R=0.74). Midazolam clearance significantly (P<0.004) explained the majority (∼60%) of the inter-individual variability in cabazitaxel clearance in the studied population. CONCLUSIONS: Metabolic phenotyping of CYP3A using midazolam is a promising strategy to individualise cabazitaxel dosing. Before clinical application, a randomised study is warranted.


Subject(s)
Antineoplastic Agents/administration & dosage , Antineoplastic Agents/pharmacokinetics , Carcinoma/drug therapy , Carcinoma/metabolism , Cytochrome P-450 CYP3A/metabolism , Prostatic Neoplasms, Castration-Resistant/drug therapy , Prostatic Neoplasms, Castration-Resistant/metabolism , Taxoids/administration & dosage , Taxoids/pharmacokinetics , Aged , Anti-Anxiety Agents/pharmacokinetics , Body Surface Area , Humans , Male , Midazolam/pharmacokinetics , Phenotype
7.
BMC Cancer ; 17(1): 282, 2017 04 19.
Article in English | MEDLINE | ID: mdl-28424071

ABSTRACT

BACKGROUND: The identification of four Consensus Molecular Subtypes (CMS1-4) of colorectal cancer forms a new paradigm for the design and evaluation of subtype-directed therapeutic strategies. The most aggressive subtype - CMS4 - has the highest chance of disease recurrence. Novel adjuvant therapies for patients with CMS4 tumours are therefore urgently needed. CMS4 tumours are characterized by expression of mesenchymal and stem-like genes. Previous pre-clinical work has shown that targeting Platelet-Derived Growth Factor Receptors (PDGFRs) and the related KIT receptor with imatinib is potentially effective against mesenchymal-type colon cancer. In the present study we aim to provide proof for the concept that imatinib can reduce the aggressive phenotype of primary CMS4 colon cancer. METHODS: Tumour biopsies from patients with newly diagnosed stage I-III colon cancer will be analysed with a novel RT-qPCR test to pre-select patients with CMS4 tumours. Selected patients (n = 27) will receive treatment with imatinib (400 mg per day) starting two weeks prior to planned tumour resection. To assess treatment-induced changes in the aggressive CMS4 phenotype, RNA sequencing will be performed on pre- and post-treatment tissue samples. DISCUSSION: The development of effective adjuvant therapy for primary colon cancer is hindered by multiple factors. First, new drugs that may have value in the prevention of (early) distant recurrence are almost always first tested in patients with heavily pre-treated metastatic disease. Second, measuring on-target drug effects and biological consequences in tumour tissue is not commonly a part of the study design. Third, due to the lack of patient selection tools, clinical trials in the adjuvant setting require large patient populations. Finally, the evaluation of recurrence-prevention requires a long-term follow-up. In the ImPACCT trial these issues are addressed by including newly diagnosed pre-selected patients with CMS4 tumours prior to primary tumour resection, rather than non-selected patients with late-stage disease. By making use of the pre-operative window period, the biological effect of imatinib treatment on CMS4 tumours can be rapidly assessed. Delivering proof-of-concept for drug action in early stage disease should form the basis for the design of future trials with subtype-targeted therapies in colon cancer patients. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02685046 . Registration date: February 9, 2016.


Subject(s)
Antineoplastic Agents/therapeutic use , Colorectal Neoplasms/drug therapy , Imatinib Mesylate/therapeutic use , Chemotherapy, Adjuvant , Clinical Trials, Phase II as Topic , Colorectal Neoplasms/pathology , Humans , Multicenter Studies as Topic , Preoperative Period , Prognosis , Research Design , Treatment Outcome
8.
Nucl Med Biol ; 42(5): 465-469, 2015 May.
Article in English | MEDLINE | ID: mdl-25662844

ABSTRACT

INTRODUCTION: (188)Rhenium-HEDP is an effective bone-targeting therapeutic radiopharmaceutical, for treatment of osteoblastic bone metastases. It is known that the presence of carrier (non-radioactive rhenium as ammonium perrhenate) in the reaction mixture during labeling is a prerequisite for adequate bone affinity, but little is known about the optimal carrier concentration. METHODS: We investigated the influence of carrier concentration in the formulation on the radiochemical purity, in-vitro hydroxyapatite affinity and the in-vivo bone accumulation of (188)Rhenium-HEDP in mice. RESULTS: The carrier concentration influenced hydroxyapatite binding in-vitro as well as bone accumulation in-vivo. Variation in hydroxyapatite binding with various carrier concentrations seemed to be mainly driven by variation in radiochemical purity. The in-vivo bone accumulation appeared to be more complex: satisfactory radiochemical purity and hydroxyapatite affinity did not necessarily predict acceptable bio-distribution of (188)Rhenium-HEDP. CONCLUSIONS: For development of new bisphosphonate-based radiopharmaceuticals for clinical use, human administration should not be performed without previous animal bio-distribution experiments. Furthermore, our clinical formulation of (188)Rhenium-HEDP, containing 10 µmol carrier, showed excellent bone accumulation that was comparable to other bisphosphonate-based radiopharmaceuticals, with no apparent uptake in other organs. ADVANCES IN KNOWLEDGE: Radiochemical purity and in-vitro hydroxyapatite binding are not necessarily predictive of bone accumulation of (188)Rhenium-HEDP in-vivo. IMPLICATIONS FOR PATIENT CARE: The formulation for (188)Rhenium-HEDP as developed by us for clinical use exhibits excellent bone uptake and variation in carrier concentration during preparation of this radiopharmaceutical should be avoided.


Subject(s)
Durapatite/chemistry , Etidronic Acid/chemistry , Radiochemistry/methods , Radioisotopes/chemistry , Radiopharmaceuticals/chemistry , Rhenium/chemistry , Animals , Bone and Bones/metabolism , Durapatite/pharmacokinetics , Durapatite/therapeutic use , Etidronic Acid/pharmacokinetics , Etidronic Acid/therapeutic use , Male , Mice , Mice, Inbred C57BL , Radiopharmaceuticals/pharmacokinetics , Radiopharmaceuticals/therapeutic use , Tissue Distribution
11.
Neth J Med ; 68(9): 371-6, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20876920

ABSTRACT

BACKGROUND: Lapatinib, a tyrosine kinase inhibitor of human epidermal growth factor receptor 2 (HER2), has shown activity in combination with capecitabine in patients with HER2-positive advanced breast cancer progressive on standard treatment regimens. We present results on preapproval drug access for this combination in such patients occurring in the general oncology practice in the Netherlands. METHODS: Patients with HER2-positive advanced breast cancer progressive on schedules containing anthracyclines, taxanes, and trastuzumab were eligible. Brain metastases were allowed if stable. Lapatinib 1250 mg÷day was given continuously in combination with capecitabine 1000 mg÷m2 twice daily for two weeks in a three-week cycle. Efficacy was assessed by use of response evaluation criteria in solid tumours version 1.0. Progression-free survival (PFS) and overall survival (OS) were calculated. RESULTS: Eighty-three patients were enrolled from January 2007 until July 2008. The combination was generally well tolerated and the most common drug-related serious adverse events were nausea and÷or vomiting (5%) and diarrhoea (2%). Seventy-eight patients were evaluable for response. Clinical benefit (response or stable disease for at least 12 weeks) was observed in 50 patients (64%) of whom 15 had a partial response and 35 stable disease. The median PFS and OS were 17 weeks (95% CI: 13 to 21) and 39 weeks (95% CI: 24 to 54), respectively. For OS, higher Eastern Cooperative Oncology Group (ECOG) status (p=0.016), brain metastases at study entry (p=0.010) and higher number of metastatic sites (p=0.012) were significantly negative predictive factors. CONCLUSION: In a patient population with heavily pretreated HER2-positive advanced breast cancer lapatinib plus capecitabine was well tolerated and offered clinical benefit.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Breast Neoplasms/drug therapy , Protein Kinase Inhibitors/therapeutic use , Quinazolines/therapeutic use , Receptor, ErbB-2/antagonists & inhibitors , Adult , Aged , Breast Neoplasms/metabolism , Breast Neoplasms/mortality , Capecitabine , Confidence Intervals , Deoxycytidine/analogs & derivatives , Deoxycytidine/therapeutic use , Female , Fluorouracil/analogs & derivatives , Fluorouracil/therapeutic use , Health Status Indicators , Humans , Kaplan-Meier Estimate , Lapatinib , Middle Aged , Multivariate Analysis , Prognosis , Proportional Hazards Models , Protein-Tyrosine Kinases/antagonists & inhibitors
12.
Int J Exp Pathol ; 84(2): 91-9, 2003 Apr.
Article in English | MEDLINE | ID: mdl-12801283

ABSTRACT

We recently described a transgenic mouse strain overexpressing hamster alphaA-crystallin, a small heat shock protein, under direction of the hamster vimentin promoter. As a result myelin was degraded and axonal dystrophy in both central nervous system (especially spinal cord) and peripheral nervous system occurred. Homozygous transgenic mice developed hind limb paralysis after 8 weeks of age and displayed progressive loss of myelin and axonal dystrophy in both the central and peripheral nervous system with ongoing age. Pathologically the phenotype resembled, to a certain extent, neuroaxonal dystrophy. The biochemical findings presented in this paper (activity of the enzymes superoxide dismutase, catalase and transglutamase, myelin protein zero expression levels and blood sugar levels) confirm this pathology and exclude other putative pathologies like Amyothrophic Lateral Sclerosis and Hereditary Motor and Sensory Neuropathy. Consequently, an excessive cytoplasmic accumulation of the transgenic protein or a disturbance of the normal metabolism are considered to cause the observed neuropathology. Therefore, extra-ocular alphaA-crystallin-expressing transgenic mice may serve as a useful animal model to study neuroaxonal dystrophy.


Subject(s)
Demyelinating Diseases/metabolism , Neuroaxonal Dystrophies/metabolism , alpha-Crystallin A Chain/metabolism , Animals , Blood Glucose/metabolism , Blotting, Southern , Blotting, Western , Catalase/metabolism , Demyelinating Diseases/etiology , Demyelinating Diseases/genetics , Disease Models, Animal , Mice , Mice, Transgenic , Myelin P0 Protein/metabolism , Neuroaxonal Dystrophies/etiology , Neuroaxonal Dystrophies/genetics , Superoxide Dismutase/metabolism , Transglutaminases/metabolism
13.
Ned Tijdschr Geneeskd ; 147(10): 457-60, 2003 Mar 08.
Article in Dutch | MEDLINE | ID: mdl-12666519

ABSTRACT

A 33-year-old man was treated for a testicular non-seminoma carcinoma with three different chemotherapeutic agents: bleomycin, etoposide en cisplatin (BEP). During the second course of BEP he experienced two cerebral infarctions and a myocardial infarction at almost the same time. A CT-scan of the brain revealed a subcortical infarction in the left hemisphere. Angiography of the head and neck arteries revealed an almost completely thrombotic left carotid artery. ECG recordings showed signs of transmural ischaemia of the heart and an echocardiogram demonstrated irreversible myocardial damage. The time interval between the chemotherapy and the complications suggests a cisplatin-related cause (such adverse effects are unknown with bleomycin or etoposide). Cisplatin toxicity can give rise to serious vascular complications for which several factors appear to be responsible, such as an increased thrombogenicity and vascular spasm due to hypomagnesaemia.


Subject(s)
Antineoplastic Agents/adverse effects , Cerebral Infarction/chemically induced , Cisplatin/adverse effects , Myocardial Infarction/chemically induced , Adult , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Bleomycin/therapeutic use , Cisplatin/therapeutic use , Etoposide/therapeutic use , Humans , Male , Testicular Neoplasms/drug therapy
14.
Eur J Biochem ; 268(3): 536-43, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11168392

ABSTRACT

The damaging effects of UV-A irradiation on lens water-insoluble alpha-crystallin, plasma membranous and cytoskeletal proteins derived from bovine lenses were studied. Young and adult bovine lenses were kept viable for 2 months in organ culture. After 24 h of incubation they were irradiated, and analyses of the proteins by one-dimensional and two-dimensional gel electrophoresis followed by Western blotting were carried out at several time intervals. RNA isolation, PCR and Northern blotting were also performed. We identified age-related changes in water-insoluble alpha-crystallin, the major membrane protein MP26 and the cytoskeletal proteins vimentin, phakinin and actin between control and UV-irradiated lenses. It appeared that adult lenses are more susceptible to UV light than young lenses, and protein modification occurred more frequently in adult lenses. UV-A irradiation affects not only the cytoskeletal structure, as deduced by the abnormal arrangement of actin in the fiber cells, but also leads to degradation of actin mRNA. Furthermore, analysis of the expression of hsp25 and hsp70 revealed some alteration in the protein pattern of adult lenses. We suggest that degradation of the cytoskeletal proteins following irradiation is due to, at least in part, the decreased protective ability of heat shock proteins upon aging.


Subject(s)
Cell Membrane/radiation effects , Crystallins/metabolism , Cytoskeleton/radiation effects , Lens, Crystalline/radiation effects , Ultraviolet Rays , Actins/metabolism , Age Factors , Aging , Animals , Blotting, Northern , Blotting, Western , Cattle , Electrophoresis, Gel, Two-Dimensional , Electrophoresis, Polyacrylamide Gel , Eye Proteins/metabolism , HSP70 Heat-Shock Proteins/metabolism , Intermediate Filament Proteins/metabolism , Microscopy, Fluorescence , Neoplasm Proteins/metabolism , Polymerase Chain Reaction , RNA/metabolism , RNA, Messenger/metabolism , Time Factors , Vimentin/metabolism
16.
FEBS Lett ; 480(2-3): 79-83, 2000 Sep 01.
Article in English | MEDLINE | ID: mdl-11034304

ABSTRACT

alphaA-Crystallin, a small heat shock protein with chaperone-like activity, forms dynamic multimeric complexes. Recently we described the spontaneous generation of a mutant protein (super alphaA-crystallin) by exon duplication arisen via exon shuffling confirming a classic hypothesis by Gilbert [Nature 271 (1978) 501]. Comparison of super alphaA-crystallin, which is viable in a mouse skeletal muscle cell line, with normal alphaA-crystallin shows that it has diminished thermostability, increased exposure of hydrophobic patches, a larger complex size and lost its chaperone activity. However, super alphaA-crystallin subunits exchange as readily between complexes as does normal alphaA-crystallin. These data indicate that chaperone-like activity may vanish independent of subunit hydrophobicity and exchangeability.


Subject(s)
Crystallins/metabolism , Exons , Molecular Chaperones/metabolism , Anilino Naphthalenesulfonates , Animals , Cell Line , Chromatography, Gel/methods , Cricetinae , Crystallins/genetics , Crystallins/isolation & purification , Fluorescence , Fluorescent Dyes , Gene Expression , Heating , Mice , Microscopy, Electron/methods , Molecular Chaperones/genetics , Molecular Chaperones/isolation & purification , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/isolation & purification , Recombinant Fusion Proteins/metabolism
17.
Invest Ophthalmol Vis Sci ; 41(12): 3893-7, 2000 Nov.
Article in English | MEDLINE | ID: mdl-11053291

ABSTRACT

PURPOSE: To determine whether alpha-crystallin is capable of forming filament-like structures with other members of the crystallin family. METHODS: Water-soluble crystallins were isolated from calf lenses and fractionated into alpha-, betaH-, betaL-, and gamma-crystallins according to standard procedures. Chaperone-like activity of alpha-crystallin was determined in control and UV-A-irradiated lenses by the heat-induced aggregation assay of betaL-crystallin. Protein samples from this assay were analyzed by electron microscopy. In vitro filament formation was examined by transmission immunoelectron microscopy using specific antibodies directed against the crystallins. Involvement of intermediate filament constituents was excluded by the results of Western blot analysis, which were all negative. Moreover, the in vitro amyloid fibril interaction test using thioflavin T (ThT) was also performed. RESULTS: At the supramolecular level heating at 60 degrees C has no effect on the morphologic appearance of alpha-crystallin as observed by transmission electron microscopy. Moreover alpha-crystallin obtained from UV-A-irradiated lenses shows a virtually identical shape. However, heating in the presence of betaL-crystallin results in the formation of filament-like alphabeta-hybrids as demonstrated by immunoelectron microscopy using specific antibodies directed either against alpha- or betaL-crystallin. Parallel experiments with alpha-crystallin derived from UV-A-irradiated lenses showed even more pronounced filamentous structures, compared with the controls. Nonetheless, we were able to show that the UV-light treatment affected the chaperone-like capacity of alpha-crystallin, as revealed by a diminished ability to inhibit in vitro denaturation of betaL-crystallin. To exclude the presence of cytoskeletal contamination in the crystallin preparations, vimentin antibodies were also tested. These latter experiments were negative. The filamentous nature of the hybrids was further confirmed by the results obtained with the ThT assay earlier applied for the detection of amyloid fibrils. CONCLUSIONS: Crystallin hybrids have previously been detected in the water-soluble lens crystallin fraction. Our findings indicate that such endogenous hybrids, formerly called "rods," may result from stress-induced interaction between alpha-crystallin and other lens constituents such as betaL-crystallin. Because the hybrid formation is enhanced when alpha-crystallin from UV-A-irradiated lenses is used as one of the two components of the hybrid, one can only speculate that this formation may be one of the factors leading to UV-A cataract.


Subject(s)
Crystallins/metabolism , Cytoskeleton/metabolism , Heat Stress Disorders/metabolism , Animals , Cattle , Chromatography, Gel , Crystallins/ultrastructure , Cytoskeletal Proteins/metabolism , Cytoskeleton/ultrastructure , Heat Stress Disorders/pathology , Lens, Crystalline/metabolism , Lens, Crystalline/radiation effects , Microscopy, Immunoelectron , Molecular Chaperones/metabolism , Organ Culture Techniques , Protein Denaturation , Ultraviolet Rays
18.
Curr Eye Res ; 21(1): 588-94, 2000 Jul.
Article in English | MEDLINE | ID: mdl-11035541

ABSTRACT

PURPOSE: To investigate alphaB-Crystallin expression and localization in the lacrimal gland and tear fluid. METHODS: Mouse, rat, porcine, monkey and human lacrimal gland samples were immuno-histochemically and immuno-electron-microscopically stained with various antibodies against alphaB-crystallin. Western- and Northern-blotting was performed to demonstrate the presence of alphaB-crystallin mRNA and protein. Human tear fluid was analyzed for the presence of alphaB-crystallin using dot blotting. RESULTS: alphaB-Crystallin is located in the lacrimal gland duct cells but not in the acini. Electron microscopically, the protein was frequently found in apical electron-dense granules of lacrimal duct cells, occasionally also in the duct lumina. Western blotting confirmed the presence of alphaB-crystallin in the lacrimal gland, Northern blot samples revealed the presence of alphaB-crystallin mRNA. In the human tear fluid, alphaB-crystallin was present in all samples investigated. CONCLUSIONS: We demonstrate for the first time that alphaB-crystallin is present in the lacrimal gland. Presence of the protein in apical secretory granules as well as presence in the tear fluid might indicate secretion of alphaB-crystallin into the tear fluid.


Subject(s)
Crystallins/metabolism , Lacrimal Apparatus/metabolism , Tears/metabolism , Aged , Aged, 80 and over , Animals , Blotting, Northern , Blotting, Western , Humans , Immunohistochemistry , Lacrimal Apparatus/cytology , Lacrimal Apparatus/ultrastructure , Macaca , Mice , Microscopy, Immunoelectron , Middle Aged , Rats , Swine , Tissue Distribution
20.
Ophthalmic Res ; 32(5): 195-204, 2000.
Article in English | MEDLINE | ID: mdl-10971180

ABSTRACT

This study is a first approach to identify UVA-related alterations in situ of bovine eye lens proteins from the water-soluble and urea-soluble fractions upon aging. The fractions were obtained from irradiated long-term organ culture lenses and analyzed by mini two-dimensional gel electrophoresis. This micropreparative method followed by computer analysis allows high resolution and separation of microgram quantities of proteins and to detect spots which arose as a consequence of irradiation. To facilitate the analysis we first separated the water-soluble fraction into the major crystallin classes by gel filtration. Moreover, we immunoblotted the gel of the urea-soluble fraction with a specific antibody against the intermediate filament protein vimentin. Upon irradiation of young and adult lenses, alphaA-crystallin and vimentin showed obvious modifications. During aging the susceptibility to irradiation increased when vimentin started to degrade, whereas deamidation of alphaA-crystallin seems to occur.


Subject(s)
Aging/metabolism , Cataract/metabolism , Crystallins/metabolism , Lens, Crystalline/radiation effects , Radiation Injuries, Experimental/metabolism , Ultraviolet Rays/adverse effects , Aging/radiation effects , Animals , Cataract/etiology , Cattle , Chromatography, Gel , Electrophoresis, Gel, Two-Dimensional/methods , Lens, Crystalline/metabolism , Organ Culture Techniques , Radiation Injuries, Experimental/etiology
SELECTION OF CITATIONS
SEARCH DETAIL
...