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1.
Neurosurgery ; 94(2): 379-388, 2024 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-37728367

RESUMO

BACKGROUND AND OBJECTIVES: Neurological manifestations may occur in more than 80% of patients hospitalized with COVID-19 infection, including severe disruptions of the central nervous system (CNS), such as strokes, encephalitis, or seizures. Although the primary pathophysiological mechanism for the effects of COVID-19 in CNS remains unknown, evidence exists for both direct injury from neuroinvasion and indirect effects from disruptions in systemic inflammatory and coagulation pathways. In this study, we analyzed CNS tissue from living patients to better understand these processes. METHODS: With institutional review board approval and patient consent, samples that would be otherwise discarded from patients with active or recent (within 6 days of surgery) COVID-19 infection undergoing neurosurgical intervention were collected and tested for the presence of SARS-CoV-2 using immunohistochemistry, in situ hybridization, electron microscopy, and reverse transcription polymerase chain reaction. RESULTS: Five patients with perioperative mild-to-moderate COVID-19 infection met inclusion criteria (2 male, 3 female; mean age 38.8 ± 13.5 years). Neurosurgical diagnoses included a glioblastoma, a ruptured arteriovenous malformation, a ruptured posterior inferior cerebellar artery aneurysm, a middle cerebral artery occlusion, and a hemorrhagic pontine cavernous malformation. Samples analyzed included the frontal lobe cortex, olfactory nerve, arteriovenous malformation/temporal lobe parenchyma, middle cerebral artery, cerebellum, and cavernous malformation/brainstem parenchyma. Testing for the presence of SARS-CoV-2 was negative in all samples. CONCLUSION: The CNS is likely not a significant viral reservoir during mild-to-moderate COVID-19 infection, although direct neuroinvasion is not definitively excluded. Additional testing to help elucidate the relative contributions of direct and indirect pathways for CNS injury from COVID is warranted.


Assuntos
Malformações Arteriovenosas , COVID-19 , Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , SARS-CoV-2 , Sistema Nervoso Central , Tronco Encefálico
2.
Clin Cancer Res ; 29(21): 4492-4503, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37585496

RESUMO

PURPOSE: Limited effective treatments are currently available for central nervous system (CNS) metastasis (CM). This is largely driven by the inability of current therapeutics to penetrate the blood brain barrier (BBB) and the lack of preclinical models for testing new therapies. Here we study the efficacy of AZD1390, a BBB penetrating ataxia-telangiectasia mutated inhibitor, as a radiosensitizer for breast cancer CM treatment. EXPERIMENTAL DESIGN: Three patient-derived xenograft (PDX) tumors including 2 HER2+ and 1 triple-negative breast cancer harboring DNA damage response (DDR) gene mutations, were implanted subcutaneously in the flank of mice to assess tumor growth inhibition by AZD1390 combined with radiation. Animal survival was further assessed by implanting the best responding PDX model orthotopically in the brain. RESULTS: Pretreatment with AZD1390 followed by radiation therapy inhibited growth of PDX tumors implanted in the flank, and improved survival in orthotopic models with average survival of 222 days compared with 123 days in controls. Administration of AZD1390 posttreatment for 21 days had no further benefits. While the combination therapy resulted in sustained tumor inhibition, sporadic regrowth was observed in some mice 50 to 100 days posttreatment in all models. Gene expression comparing these tumors with complete responders demonstrated changes in upregulation of oncogenic proteins, which are potential drivers of tumor growth after treatment. CONCLUSIONS: Our results demonstrate that AZD1390 effectively sensitizes breast cancer CM to radiation therapy in DDR mutant tumors. This study demonstrates the potential of using AZD1390 as a novel therapeutic agent for patients with breast cancer CM.


Assuntos
Neoplasias do Sistema Nervoso Central , Segunda Neoplasia Primária , Radiossensibilizantes , Neoplasias de Mama Triplo Negativas , Humanos , Camundongos , Animais , Radiossensibilizantes/farmacologia , Radiossensibilizantes/uso terapêutico , Inibidores de Proteínas Quinases/farmacologia , Neoplasias do Sistema Nervoso Central/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/patologia , Modelos Animais de Doenças , Segunda Neoplasia Primária/tratamento farmacológico , Linhagem Celular Tumoral , Ensaios Antitumorais Modelo de Xenoenxerto , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Melanoma Maligno Cutâneo
3.
J Neurosurg Case Lessons ; 4(8)2022 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-36088606

RESUMO

BACKGROUND: Intranasal delivery of NEO100, a pharmaceutical-grade version of the natural monoterpene perillyl alcohol (POH), is undergoing clinical phase IIa testing as a treatment for glioblastoma (GBM). However, so far there is no evidence that intranasal delivery of NEO100 indeed results in POH reaching intracranial malignancies in a patient. OBSERVATIONS: After surgical removal of her recurrent GBM tumor, a patient received daily intranasal NEO100 therapy for more than 3 years before a second recurrence emerged. At that time, a final dose of NEO100 was given shortly before the tumor tissue was surgically removed, and the tissue was processed for high-performance liquid chromatography analysis of POH and its primary metabolite, perillic acid (PA). Both molecules could readily be detected in the tumor tissue. LESSONS: This is the first demonstration of POH and PA in brain tumor tissue from any patient. It reveals that intranasal administration of NEO100 is a valid approach to achieve delivery of this agent to a brain tumor. In view of the noninvasive and safe nature of this method, along with tentative indications of activity, our findings add confidence to the notion that intranasal administration of NEO100 holds potential as a new treatment option for brain-localized malignancies.

4.
Clin Neurol Neurosurg ; 207: 106795, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34273663

RESUMO

Reducing body myopathy (RBM) is a rare muscle disorder, with marked presence of characteristic intracytoplasmic aggregates in affected muscle fibers. RBM is associated with FHL1 gene mutations. Clinical presentations of RBM have ranged from early fatal to adult onset progressive muscle weakness. We present herein the clinical, electrodiagnostic, and muscle biopsy findings of a 17-year-old female with progressive muscle weakness and contracture. Muscle biopsy showed atrophic fibers that contained menadione nitroblue tetrazolium (NBT) positive reducing bodies. Genetic testing revealed a variant of uncertain significance in the FHL1 gene at a position known to be pathogenic when substituted by other amino acids (p.His123Arg). This variant was later reclassified as pathogenic.


Assuntos
Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas com Domínio LIM/genética , Proteínas Musculares/genética , Doenças Musculares/genética , Doenças Musculares/patologia , Adolescente , Feminino , Humanos , Corpos de Inclusão/genética , Corpos de Inclusão/patologia , Mutação
5.
Prostate ; 81(8): 469-477, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33848377

RESUMO

BACKGROUND: Neuroendocrine prostatic carcinoma (NEPC) is uncommon. The pathogenesis, clinical association, and clinical implications of this disease are still evolving. METHODS: Clinicopathologic, immunohistochemical and genomic studies were used to investigate the incidence of NEPC in various clinicopathologic settings and the expression of various biomarkers in NEPC and non-NEPC as well as small cell NEPC. The study included 45 treatment-naïve Gleason pattern (GP) 3 and 94 GP 4/5, 43 post-radiation, 60 post-androgen deprivation therapy (ADT), 38 lymph node metastatic and 9 small cell prostatic adenocarcinomas (PCs). RESULTS: NEPC was found in 7% GP3, 10% GP4/5, 9% post-radiation, 18% post-ADT, and 5% lymph node metastatic PCs, respectively. Compared with treatment-naïve PCs, post-ADT PCs showed significantly increased incidence of NEPC (p < .05) while no significant difference was noted between low- and high-grade PCs, post-radiation, and lymph node metastatic PCs. Serotonin was uniformly positive in NE cells of benign glands but negative in NEPC. Significant increase of Bcl-2 and Auro A and decrease of prostein were noted in NEPC (p < .05). No significant changes in the expression of other biomarkers were found. In addition, small cell NEPC was strongly associated with ADT (44%) and high Gleason score (≥8, 100%) and often presented with alterations of TP53/RB1 and ARID1A/B or other genes crucial to genomic fidelity. CONCLUSION: Given that no specific treatment for NEPC is presently available, the findings in this study have significant implications in the better understanding of this often-deadly disease both clinically and pathogenetically as well as future patient management, including targeted therapy.


Assuntos
Adenocarcinoma/metabolismo , Biomarcadores Tumorais/metabolismo , Carcinoma Neuroendócrino/metabolismo , Próstata/metabolismo , Neoplasias da Próstata/metabolismo , Adenocarcinoma/genética , Adenocarcinoma/patologia , Idoso , Biomarcadores Tumorais/genética , Carcinoma Neuroendócrino/genética , Carcinoma Neuroendócrino/patologia , Cromograninas/metabolismo , Progressão da Doença , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Gradação de Tumores , Próstata/patologia , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Sinaptofisina/metabolismo
6.
Neurooncol Adv ; 3(1): vdab005, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33604574

RESUMO

BACKGROUND: Better treatments for glioblastoma (GBM) patients, in particular in the recurrent setting, are urgently needed. Clinical trials performed in Brazil indicated that intranasal delivery of perillyl alcohol (POH) might be effective in this patient group. NEO100, a highly purified version of POH, was current good manufacturing practice (cGMP) manufactured to evaluate the safety and efficacy of this novel approach in a Phase I/IIa clinical trial in the United States. METHODS: A total of 12 patients with recurrent GBM were enrolled into Phase I of this trial. NEO100 was administered by intranasal delivery using a nebulizer and nasal mask. Dosing was 4 times a day, every day. Four cohorts of 3 patients received the following dosages: 96 mg/dose (384 mg/day), 144 mg/dose (576 mg/day), 192 mg/dose (768 mg/day), and 288 mg/dose (1152 mg/day). Completion of 28 days of treatment was recorded as 1 cycle. Adverse events were documented, and radiographic response via Response Assessment in Neuro-Oncology (RANO) criteria was evaluated every 2 months. Progression-free and overall survival were determined after 6 and 12 months, respectively (progression-free survival-6 [PFS-6], overall survival-12 [OS-12]). RESULTS: Intranasal NEO100 was well tolerated at all dose levels and no severe adverse events were reported. PFS-6 was 33%, OS-12 was 55%, and median OS was 15 months. Four patients (33%), all of them with isocitrate dehydrogenase 1 (IDH1)-mutant tumors, survived >24 months. CONCLUSION: Intranasal glioma therapy with NEO100 was well tolerated. It correlated with improved survival when compared to historical controls, pointing to the possibility that this novel intranasal approach could become useful for the treatment of recurrent GBM.

7.
Pathol Res Pract ; 215(10): 152536, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31326195

RESUMO

Primitive neuroectodermal tumor (PNET) traditionally encompasses two different classes of tumors with similar morphology - PNET of the peripheral nervous system (pPNET) and PNET of the central nervous system (cPNET). The latter also includes germ cell tumor-derived PNET (gPNET). There are currently no specific markers for gPNET. This study seeks to investigate the expression of ZBTB16 in PNET and other small round blue cell tumors as well as its potential diagnostic utility. Immunohistochemical expression of the ZBTB16 was studied in a total of 27 PNETs (12 pPNETs, 8 cPNETs, 3 primary testicular gPNETs, and 4 metastatic gPNETs) and 38 small round blue cell tumors. Positive expression for ZBTB16 was seen diffusely in 9/12 (75%), moderately in 2/12 (17%) and focally in 1/12 (8%) of pPNETs, diffusely in 3/7 (43%) and moderately in 4/7 (57%) of gPNETs, and diffusely in 2/8 (25%), moderately in 2/8 (25%) and focally in 4/8 (50%) of cPNETs. Whereas, all of the 38 non-PNET small round blue cell tumors were nonreactive. The results suggest that ZBTB16 is a highly sensitive and specific biomarker for both pPNET and gPNET/cPNET. ZBTB16 effectively differentiates PNETs from other small round blue cell tumor mimics, including the two most common germ cell tumor-derived somatic malignancies - rhabdomyosarcoma and nephroblastoma. Of note, compared to the expression of ZBTB16 in pPNET/Ewing sarcoma and gPNET, the expression of ZBTB16 in cPNET was more variable, which appears consistent with the heterogeneity of cPNET. The close proximity of ZBTB16 and FLI-1 genes on chromosome 11q may explain the overexpression of ZBTB16 in PNET, especially in pPNET with t(1122) translocation.


Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias Ósseas/diagnóstico , Tumores Neuroectodérmicos Primitivos/diagnóstico , Proteína com Dedos de Zinco da Leucemia Promielocítica/metabolismo , Rabdomiossarcoma/diagnóstico , Sarcoma de Ewing/diagnóstico , Neoplasias de Tecidos Moles/diagnóstico , Tumor de Wilms/diagnóstico , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/patologia , Diagnóstico Diferencial , Feminino , Humanos , Imuno-Histoquímica , Masculino , Tumores Neuroectodérmicos Primitivos/metabolismo , Tumores Neuroectodérmicos Primitivos/patologia , Rabdomiossarcoma/metabolismo , Rabdomiossarcoma/patologia , Sarcoma de Ewing/metabolismo , Sarcoma de Ewing/patologia , Sensibilidade e Especificidade , Neoplasias de Tecidos Moles/metabolismo , Neoplasias de Tecidos Moles/patologia , Tumor de Wilms/metabolismo , Tumor de Wilms/patologia
8.
Oper Neurosurg (Hagerstown) ; 16(6): 675-684, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-30247673

RESUMO

BACKGROUND: Limited data exist pertaining to outcomes following surgery for recurrent Rathke's cleft cysts (RCC). OBJECTIVE: To determine treatment outcomes in patients undergoing reoperation for recurrent or residual RCCs. METHODS: A retrospective analysis of 112 consecutive RCC operations in 109 patients between 1995 and 2017 was conducted. RESULTS: Eighteen patients underwent 21 RCC reoperations with a mean follow-up of 58 mo. Patient symptoms prior to reoperation included headaches (14, 66.7%) and vision loss (12, 57.1%). Thirteen of 18 patients (72.2%) required hormone supplementation prior to reoperation including 5 with diabetes insipidus (DI). Mean RCC diameter was 16 mm and 76% had suprasellar extension. Compared to index RCC cases, intraoperative cerebrospinal fluid leak repair was more common in reoperation cases (15/21, 71% vs 43/91, 47%, P = .05). There was 1 carotid artery injury without neurological sequelae, and 2 postoperative cerebrospinal fluid (CSF) leaks (9.5%). Rates of transient hyponatremia (3/10, 30% vs 4/91, 4.4%, P = .04) and transient DI (5/10, 50% vs 17/91, 18.7%, P = .04) were higher in the reoperation vs index group. Improved headaches and vision were reported in 4/12 (33%) and 8/12 (61.5%) of RCC reoperation patients, respectively. Two patients developed new permanent DI. A higher proportion of reoperation patients had RCC squamous metaplasia (24% vs 5.4%, P = .02) or wall inflammation (42.9% vs 2.2%, P < .001) on pathological examination. CONCLUSION: Reoperation for RCCs is generally safe at tertiary pituitary centers and often results in improved vision. Hypopituitarism is less likely to improve following reoperation for recurrent RCCs. Several histopathological features may help characterize "atypical RCCs" with a higher likelihood of recurrence/progression.


Assuntos
Cistos do Sistema Nervoso Central/cirurgia , Recidiva Local de Neoplasia/cirurgia , Neoplasias Hipofisárias/cirurgia , Hormônio Adrenocorticotrópico/deficiência , Adulto , Idoso , Lesões das Artérias Carótidas/epidemiologia , Cistos do Sistema Nervoso Central/complicações , Vazamento de Líquido Cefalorraquidiano/epidemiologia , Vazamento de Líquido Cefalorraquidiano/cirurgia , Craniotomia , Diabetes Insípido/tratamento farmacológico , Diabetes Insípido/epidemiologia , Diabetes Insípido/etiologia , Feminino , Glucocorticoides/uso terapêutico , Humanos , Hipogonadismo/tratamento farmacológico , Hipogonadismo/etiologia , Hipotireoidismo/tratamento farmacológico , Hipotireoidismo/etiologia , Síndrome de Secreção Inadequada de HAD/tratamento farmacológico , Síndrome de Secreção Inadequada de HAD/epidemiologia , Incidência , Complicações Intraoperatórias/cirurgia , Masculino , Microcirurgia , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/epidemiologia , Neuroendoscopia , Neoplasias Hipofisárias/complicações , Complicações Pós-Operatórias/epidemiologia , Reoperação , Centros de Atenção Terciária
9.
Ocul Oncol Pathol ; 4(1): 33-37, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29344496

RESUMO

PURPOSE: The aim of this study was to describe a 34-year-old male with hereditary bilateral retinoblastoma treated with radiotherapy as a child who developed 4 distinct tumors within the radiation field. METHODS: A 34-year-old male with bilateral retinoblastoma status postradiation therapy and recurrence requiring enucleation presented with left-eye visual acuity changes. Magnetic resonance imaging demonstrated a left orbital mass and a right parasellar complex lobulated mass (right sphenoid and right cavernous sinus). Two weeks later, the patient underwent excision of the orbital mass and biopsy of an upper-lid nodule. This was followed by craniotomy for removal of the complex mass. RESULTS: Histology revealed 4 distinct tumors, including an undifferentiated pleomorphic sarcoma (left orbit), a radiation-induced meningioma (right sphenoid), a schwannoma (right cavernous sinus), and a basal-cell carcinoma (left lid). CONCLUSION: Although occurrence of a second neoplasm is a well-known outcome following radiation treatment in patients with hereditary retinoblastoma, the diagnosis of 4 additional neoplasms is rare. Pleomorphic sarcoma, radiation-induced meningioma, and schwannoma are uncommon tumors and not well represented in the literature describing irradiated retinoblastoma patients. Secondary malignancies are a leading cause of early death in retinoblastoma survivors, and long-term follow-up is crucial for patient care.

10.
J Neural Transm (Vienna) ; 121(2): 171-81, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23996276

RESUMO

The α-synuclein-immunoreactive pathology of dementia associated with Parkinson disease (DPD) comprises Lewy bodies (LB), Lewy neurites (LN), and Lewy grains (LG). The densities of LB, LN, LG together with vacuoles, neurons, abnormally enlarged neurons (EN), and glial cell nuclei were measured in fifteen cases of DPD. Densities of LN and LG were up to 19 and 70 times those of LB, respectively, depending on region. Densities were significantly greater in amygdala, entorhinal cortex (EC), and sectors CA2/CA3 of the hippocampus, whereas middle frontal gyrus, sector CA1, and dentate gyrus were least affected. Low densities of vacuoles and EN were recorded in most regions. There were differences in the numerical density of neurons between regions, but no statistical difference between patients and controls. In the cortex, the density of LB and vacuoles was similar in upper and lower laminae, while the densities of LN and LG were greater in upper cortex. The densities of LB, LN, and LG were positively correlated. Principal components analysis suggested that DPD cases were heterogeneous with pathology primarily affecting either hippocampus or cortex. The data suggest in DPD: (1) ratio of LN and LG to LB varies between regions, (2) low densities of vacuoles and EN are present in most brain regions, (3) degeneration occurs across cortical laminae, upper laminae being particularly affected, (4) LB, LN and LG may represent degeneration of the same neurons, and (5) disease heterogeneity may result from variation in anatomical pathway affected by cell-to-cell transfer of α-synuclein.


Assuntos
Encéfalo/metabolismo , Encéfalo/patologia , Demência , Doença de Parkinson , alfa-Sinucleína/metabolismo , Idoso , Idoso de 80 Anos ou mais , Peptídeos beta-Amiloides/metabolismo , Proteínas de Ligação a DNA/metabolismo , Demência/complicações , Demência/metabolismo , Demência/patologia , Feminino , Humanos , Corpos de Lewy/metabolismo , Corpos de Lewy/patologia , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Emaranhados Neurofibrilares/patologia , Neuroglia/metabolismo , Neuroglia/patologia , Neurônios/metabolismo , Doença de Parkinson/complicações , Doença de Parkinson/metabolismo , Doença de Parkinson/patologia , Ubiquitina/metabolismo , Vacúolos/metabolismo , Vacúolos/patologia
11.
J Med Case Rep ; 6: 341, 2012 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-23043797

RESUMO

INTRODUCTION: Langerhans cell histiocytosis is a rare disease within the adult population, with very few cases reported as solitary hypophyseal lesions in adults. Of the reported cases, most have been treated successfully with surgery, radiotherapy, and/or chemotherapy. Radiotherapy has been thought to be curative at the relatively low dose of 20Gy. Here we report a case of recurrent hypophyseal Langerhans cell histiocytosis 9 months after radiotherapy with an interval period of symptomatic and radiographic response to therapy. CASE PRESENTATION: A 50-year-old Caucasian woman who had headaches, memory difficulties, and diabetes insipidus was found to have a 2.5cm suprasellar mass. Langerhans cell histiocytosis was diagnosed following stereotactic brain biopsy. Further workup revealed no other lesions. Initial radiation treatment succeeded in shrinking the tumor and relieving clinical symptoms temporarily; however, growth and recurrence of clinical symptoms was noted at 9 months. Re-irradiation was well tolerated and the patient had no acute side effects. CONCLUSION: Isolated hypophyseal involvement by Langerhans cell histiocytosis in adults is a unique presentation of a rare disease. Although radiotherapy doses as low as 20Gy have been reported to offer control, this case demonstrates that higher doses may be warranted to ensure tumor control. With modern imaging and radiotherapy techniques higher doses should offer little increased more durable risk to surrounding critical structures.

13.
Biochemistry ; 43(7): 1891-907, 2004 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-14967030

RESUMO

Site-directed spin labeling (SDSL), the site-specific incorporation of nitroxide spin-labels into a protein, has allowed us to investigate ligand-induced conformational changes in the ligand-binding domain of human estrogen receptor alpha (hERalpha-LBD). EPR (electron paramagnetic resonance) spectroscopy of the nitroxide probe attached to ER produces different spectra depending upon the identity of the bound ligand; these differences are indicative of changes in the type and degree of motional character of the spin-label induced by different ligand-induced conformations of labeled ER. Visual inspection of EPR spectra, construction of B versus C cross-correlation plots, and cross-comparison of spectral pairs using a relative squared difference (RSD) calculation allowed receptor-ligand complexes to be profiled according to their conformational character. Plotting B and C parameters allowed us to evaluate the liganded receptor according to the motional characteristics of the attached spin-label, and they were particularly illustrative for the receptor labeled at position 530, which had motion between the fast and intermediate regimes. RSD analysis allowed us to directly compare the similarity or difference between two different spectra, and these comparisons produced groupings that paralleled those seen in B versus C cross-correlation plots, again relating meaningfully with the pharmacological nature of the bound ligand. RSD analysis was also particularly useful for qualifying differences seen with the receptor labeled at position 417, which had motion between the intermediate and slow motional regimes. This work demonstrates that B and C formulas from EPR line shape theory are useful for qualitative analysis of spectra with differences subtler than those that are often analyzed by EPR spectroscopists. This work also provides evidence that the ER can exist in a range of conformations, with specific conformations resulting from preferential stabilization of ER by the bound ligand. Furthermore, it documents the complexity and uniqueness of the ligand-receptor structure, and highlights the fact that structural differences exist between the receptor bound with ligands of different pharmacological character that, nevertheless, produce similar crystal structures.


Assuntos
Estradiol/análogos & derivados , Mutagênese Sítio-Dirigida , Receptores de Estrogênio/química , Receptores de Estrogênio/genética , Marcadores de Spin , Substituição de Aminoácidos/genética , Sítios de Ligação , Óxidos N-Cíclicos/metabolismo , Cisteína/genética , Cisteína/metabolismo , Espectroscopia de Ressonância de Spin Eletrônica , Estradiol/química , Estriol/química , Receptor alfa de Estrogênio , Estrona/química , Humanos , Análise dos Mínimos Quadrados , Ligantes , Modelos Lineares , Conformação Proteica , Estrutura Terciária de Proteína/genética , Receptores de Estrogênio/metabolismo , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
14.
Mol Endocrinol ; 16(12): 2706-19, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12456792

RESUMO

Nuclear receptors form strong dimers that are essential for their function as transcription factors, and it is thought that ligand binding can affect dimer stability. In this report, we describe convenient fluorescence resonance energy transfer (FRET)-based methods for measuring the thermodynamic and kinetic stability of dimers of the estrogen receptor-alpha ligand-binding domain (ERalpha-LBD). We have developed receptors that are chemically labeled with a single fluorophore in a site-specific manner. These fluorophore-labeled ERs are functional and can be used to measure directly the affinity and stability of ERalpha-LBD dimers. Our results indicate that unliganded ERalpha-LBDs exist as very stable dimers and that the dissociation rate of these dimers is slow (t(1/2)=39 +/- 3 min at 28 C) and is further slowed (< or =7-fold) by the addition of various ligands. Estrogen antagonists provide greater kinetic stabilization of the ER dimers than agonists. In addition, coactivator peptides containing the LXXLL motif selectively stabilize agonist-bound ERalpha-LBD dimers. These fluorescence-based assays for measuring the kinetic and thermodynamic stability of ER dimers provide a functional in vitro method for assessing the agonist or antagonist character of novel ligands.


Assuntos
Dimerização , Receptores de Estrogênio/química , Receptores de Estrogênio/metabolismo , Sítios de Ligação , Cisteína/química , Estabilidade de Medicamentos , Transferência de Energia , Estradiol/metabolismo , Antagonistas de Estrogênios/química , Antagonistas de Estrogênios/metabolismo , Antagonistas de Estrogênios/farmacologia , Receptor alfa de Estrogênio , Estrogênios/química , Estrogênios/metabolismo , Corantes Fluorescentes , Histona Acetiltransferases , Humanos , Cinética , Ligantes , Modelos Moleculares , Estrutura Molecular , Mutagênese Sítio-Dirigida , Coativador 1 de Receptor Nuclear , Ligação Proteica , Espectrometria de Fluorescência , Relação Estrutura-Atividade , Termodinâmica , Fatores de Transcrição/farmacologia , Trítio
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