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Background: Anti-IgLON5 disease is a rare chronic autoimmune disorder characterized by IgLON5 autoantibodies predominantly of the IgG4 subclass. Distinct pathogenic effects were described for anti-IgLON5 IgG1 and IgG4, however, with uncertain clinical relevance. Methods: IgLON5-specific IgG1-4 levels were measured in 46 sera and 20 cerebrospinal fluid (CSF) samples from 13 HLA-subtyped anti-IgLON5 disease patients (six females, seven males) using flow cytometry. Intervals between two consecutive serum or CSF samplings (31 and 10 intervals, respectively) were categorized with regard to the immunomodulatory treatment active at the end of the interval, changes of anti-IgLON5 IgG1 and IgG4 levels, and disease severity. Intrathecal anti-IgLON5 IgG4 synthesis (IS) was assessed using a quantitative method. Results: The median age at onset was 66 years (range: 54-75), disease duration 10 years (range: 15-156 months), and follow-up 25 months (range: 0-83). IgLON5-specific IgG4 predominance was observed in 38 of 46 (83%) serum and 11 of 20 (55%) CSF samples. Anti-IgLON5 IgG4 levels prior clinical improvement in CSF but not serum were significantly lower than in those prior stable/progressive disease. Compared to IgLON5 IgG4 levels in serum, CSF levels in HLA-DRB1*10:01 carriers were significantly higher than in non-carriers. Indeed, IgLON5-specific IgG4 IS was demonstrated not only in four of five HLA-DRB1*10:01 carriers but also in one non-carrier. Immunotherapy was associated with decreased anti-IgGLON5 IgG serum levels. In CSF, lower anti-IgLON5 IgG was associated with immunosuppressive treatments used in combination, that is, corticosteroids and/or azathioprine plus intravenous immunoglobulins or rituximab. Conclusion: Our findings might indicate that CSF IgLON5-specific IgG4 is frequently produced intrathecally, especially in HLA-DRB1*10:01 carriers. Intrathecally produced IgG4 may be clinically relevant. While many immunotherapies reduce serum IgLON5 IgG levels, more intense immunotherapies induce clinical improvement and may be able to target intrathecally produced anti-IgLON5 IgG. Further studies need to confirm whether anti-IgLON5 IgG4 IS is a suitable prognostic and predictive biomarker in anti-IgLON5 disease.
Assuntos
Autoanticorpos , Imunoglobulina G , Humanos , Feminino , Imunoglobulina G/líquido cefalorraquidiano , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Masculino , Pessoa de Meia-Idade , Idoso , Autoanticorpos/sangue , Autoanticorpos/imunologia , Autoanticorpos/líquido cefalorraquidiano , Moléculas de Adesão Celular Neuronais/imunologia , Antígenos HLA/imunologia , Relevância ClínicaRESUMO
Anti-IgLON5 disease is a rare neurological, probably autoimmune, disorder associated in many cases with a specific tauopathy. Only a few post-mortem neuropathological studies have been reported so far. Little is known about the pathogenic mechanisms that result in neurodegeneration. We investigated the neuropathology of anti-IgLON5 disease and characterized cellular and humoral inflammation. We included nine cases (six of them previously published). Median age of patients was 71 years (53-82 years), the median disease duration was 6 years (0.5-13 years), and the female to male ratio was 5:4. Six cases with a median disease duration of 9 years presented a prominent tauopathy. Five of them had a classical anti-IgLON5-related brainstem tauopathy and another presented a prominent neuronal and glial 4-repeat tauopathy, consistent with progressive supranuclear palsy (PSP). Three cases with short disease duration (median 1.25 years) only showed a primary age-related neurofibrillary pathology. Inflammatory infiltrates of T and B cells were mild to moderate and did not significantly differ between anti-IgLON5 disease cases with or without tauopathy. In contrast, we found an extensive neuropil deposition of IgG4 in the tegmentum of the brainstem, olivary nucleus, and cerebellar cortex that was most prominent in two patients with short disease duration without the typical IgLON5-related tauopathy. The IgG4 deposits were particularly prominent in the cerebellar cortex and in these regions accompanied by mild IgG1 deposits. Activated complement deposition (C9neo) was absent. Our study indicates that IgLON5-related tau pathology occurs in later disease stages and may also present a PSP-phenotype with exclusively 4-repeat neuronal and glial tau pathology. The prominent deposition of anti-IgLON5 IgG4 at predilection sites for tau pathology suggests that anti-IgLON5 antibodies precede the tau pathology. Early start of immunotherapy might prevent irreversible neuronal damage and progression of the disease, at least in a subgroup of patients.
Assuntos
Encefalite , Doença de Hashimoto , Proteínas tau , Idoso , Feminino , Humanos , Masculino , Autopsia , Encefalite/patologia , Doença de Hashimoto/patologia , Imunoglobulina G , Moléculas de Adesão Celular Neuronais , Proteínas tau/análiseRESUMO
Early-onset dementia (EOD), with symptom onset before age 65, has a strong genetic burden. Due to genetic and clinical overlaps between different types of dementia, whole-exome sequencing (WES) has emerged as an appropriate screening method for diagnostic testing and novel gene-finding approaches. We performed WES and C9orf72 repeat testing in 60 well-defined Austrian EOD patients. Seven patients (12%) carried likely disease-causing variants in monogenic genes, PSEN1, MAPT, APP, and GRN. Five patients (8%) were APOE4 homozygote carriers. Definite and possible risk variants were detected in the genes TREM2, SORL1, ABCA7 and TBK1. In an explorative approach, we cross-checked rare gene variants in our cohort with a curated neurodegeneration candidate gene list and identified DCTN1, MAPK8IP3, LRRK2, VPS13C and BACE1 as promising candidate genes. Conclusively, 12 cases (20%) carried variants relevant to patient counseling, comparable to previously reported studies, and can thus be considered genetically resolved. Reduced penetrance, oligogenic inheritance and not yet identified high-risk genes might explain the high number of unresolved cases. To address this issue, we provide complete genetic and phenotypic information (uploaded to the European Genome-phenome Archive), enabling other researchers to cross-check variants. Thereby, we hope to increase the chance of independently finding the same gene/variant-hit in other well-defined EOD patient cohorts, thus confirming new genetic risk variants or variant combinations.
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Doença de Alzheimer , Humanos , Idoso , Doença de Alzheimer/genética , Secretases da Proteína Precursora do Amiloide/genética , Predisposição Genética para Doença , Áustria , Ácido Aspártico Endopeptidases/genética , Testes Genéticos , Mutação , Proteínas Relacionadas a Receptor de LDL/genética , Proteínas de Membrana Transportadoras/genéticaRESUMO
The COVID-19 pandemic led to unprecedented restrictions on social contacts and mobility. Memory clinic patients were disproportionately affected when care was disrupted and routines were abruptly changed. This trial was designed as a pragmatic, prospective, observational study to evaluate the effects of lockdown on memory clinic patients. Outpatients were included when they returned in May to July 2020 for their first follow-up after the lockdown. Indicators of lockdown intensity and its effect on patients were recorded, patients and caregivers were interviewed, and neuropsychological tests were performed. We included 72 patients, most of them suffering from Alzheimer's dementia or mild cognitive impairment. The median time of isolation was 8 weeks and social contacts were significantly reduced from five to two per week (p<0.001). Light physical activity was significantly reduced (3.8 hours to 3 hours, p=0.016) during the lockdown, and this reduction was significantly correlated with higher scores on the Neuropsychiatric Inventory score (R -0.43, p>0.001). Fears regarding the pandemic were common and mostly related to the patients' health. Lockdown restrictions reduced physical activity in memory clinic patients which was associated with increased neuropsychiatric symptoms. Future restrictions should aim to mitigate the impacts on this vulnerable population.
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COVID-19 , Pandemias , Controle de Doenças Transmissíveis , Exercício Físico , Humanos , Estudos Prospectivos , SARS-CoV-2RESUMO
Objective: Anti-IgLON5 disease forms an interface between neuroinflammation and neurodegeneration and includes clinical phenotypes that are often similar to those of neurodegenerative diseases. An early diagnosis of patients with anti-IgLON5 disease and differentiation from neurodegenerative diseases is necessary and may have therapeutic implications. Methods: In our small sample size study we investigated oculomotor function as a differentiating factor between anti-IgLON5 disease and neurodegenerative disorders. We examined ocular motor and vestibular function in four patients suffering from anti-IgLON5 disease using video-oculography (VOG) and a computer-controlled rotational chair system (sampling rate 60 Hz) and compared the data with those from ten age-matched patients suffering from progressive supranuclear palsy (PSP) and healthy controls (CON). Results: Patients suffering from anti-IgLON5 disease differed from PSP most strikingly in terms of saccade velocity and accuracy, the presence of square wave jerks (SWJ) (anti-IgLON5 0/4 vs. PSP 9/10) and the clinical finding of supranuclear gaze palsy (anti-IgLON5 1/4). The presence of nystagmus, analysis of smooth pursuit eye movements, VOR and VOR suppression was reliable to differentiate between the two disease entities. Clear differences in all parameters, although not always significant, were found between all patients and CON. Discussion: We conclude that the use of VOG as a tool for clinical neurophysiological assessment can be helpful in differentiating between patients with PSP and patients with anti-IgLON5 disease. VOG could have particular value in patients with suspected PSP and lack of typical Parkinson's characteristics. future trials are indispensable to assess the potential of oculomotor function as a biomarker in anti-IgLON5 disease.
Assuntos
Autoanticorpos/imunologia , Autoantígenos/imunologia , Doenças Autoimunes do Sistema Nervoso/diagnóstico , Moléculas de Adesão Celular Neuronais/imunologia , Doenças Neuroinflamatórias/fisiopatologia , Transtornos da Motilidade Ocular/fisiopatologia , Idoso , Autoanticorpos/sangue , Doenças Autoimunes do Sistema Nervoso/imunologia , Doenças Autoimunes do Sistema Nervoso/fisiopatologia , Diagnóstico Diferencial , Eletroculografia , Tecnologia de Rastreamento Ocular , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doenças Neurodegenerativas/diagnóstico , Doenças Neuroinflamatórias/diagnóstico , Doenças Neuroinflamatórias/imunologia , Nistagmo Patológico/etiologia , Transtornos da Motilidade Ocular/imunologia , Fenótipo , Reflexo Anormal , Reflexo Vestíbulo-Ocular/fisiologia , Estudos Retrospectivos , Movimentos Sacádicos/fisiologia , Paralisia Supranuclear Progressiva/diagnóstico , Paralisia Supranuclear Progressiva/imunologia , Paralisia Supranuclear Progressiva/fisiopatologia , Gravação em VídeoRESUMO
OBJECTIVE: Anti-IgLON5 disease is a recently described neurological disease that shares features of autoimmunity and neurodegeneration. Abnormal movements appear to be frequent and important but have not been characterized and are under-reported. Here we describe the frequency and types of movement disorders in a series of consecutive patients with this disease. METHODS: In this retrospective, observational study, the presence and phenomenology of movement disorders were assessed with a standardized clinical questionnaire. Available videos were centrally reviewed by three experts in movement disorders. RESULTS: Seventy two patients were included. In 41 (57%) the main reason for initial consultation was difficulty walking along with one or several concurrent movement disorders. At the time of anti-IgLON5 diagnosis, 63 (87%) patients had at least one movement disorder with a median of three per patient. The most frequent abnormal movements were gait and balance disturbances (52 patients, 72%), chorea (24, 33%), bradykinesia (20, 28%), dystonia (19, 26%), abnormal body postures or rigidity (18, 25%), and tremor (15, 21%). Other hyperkinetic movements (myoclonus, akathisia, myorhythmia, myokymia, or abdominal dyskinesias) occurred in 26 (36%) patients. The craniofacial region was one of the most frequently affected by multiple concurrent movement disorders (23 patients, 32%) including dystonia (13), myorhythmia (6), chorea (4) or myokymia (4). Considering any body region, the most frequent combination of multiple movement disorders consisted of gait instability or ataxia associated with craniofacial dyskinesias or generalized chorea observed in 31(43%) of patients. In addition to abnormal movements, 87% of patients had sleep alterations, 74% bulbar dysfunction, and 53% cognitive impairment. Fifty-five (76%) patients were treated with immunotherapy, resulting in important and sustained improvement of the movement disorders in only seven (13%) cases. CONCLUSIONS: Movement disorders are a frequent and leading cause of initial neurological consultation in patients with anti-IgLON5 disease. Although multiple types of abnormal movements can occur, the most prevalent are disorders of gait, generalized chorea, and dystonia and other dyskinesias that frequently affect craniofacial muscles. Overall, anti-IgLON5 disease should be considered in patients with multiple movement disorders, particularly if they occur in association with sleep alterations, bulbar dysfunction, or cognitive impairment.
RESUMO
Purely torsional spontaneous nystagmus almost always has a central vestibular cause. We describe a man with spontaneous pulse-synchronous torsional nystagmus in which the clockwise component corresponded to his pulse upswing, in keeping with a peripheral vestibular cause; following imaging we diagnosed left-sided superior canal dehiscence syndrome. Identifying pulse synchronicity of spontaneous nystagmus may help to distinguish central from peripheral vestibular torsional nystagmus, and is readily confirmed at the bedside using Frenzel's glasses and a pulse oximeter.
Assuntos
Nistagmo Patológico , Humanos , MasculinoRESUMO
PURPOSE: AT04A and AT06A are two AFFITOPE® peptide vaccine candidates being developed for the treatment of hypercholesterolemia by inducing proprotein convertase subtilisin/kexin type 9 (PCSK9)-specific antibodies. This study aimed to investigate safety, tolerability, antibody development, and reduction of low-density lipoprotein cholesterol (LDLc) following four subcutaneous immunizations. METHODS: This phase I, single-blind, randomized, placebo-controlled study was conducted in a total of 72 healthy subjects with a mean fasting LDLc level at baseline of 117.1 mg/dL (range 77-196 mg/dL). Each cohort enrolled 24 subjects to receive three priming immunizations at weeks 0, 4, and 8 and to receive a single booster immunization at week 60 of either AT04A, AT06A, or placebo. In addition to safety (primary objective), the antigenic peptide- and PCSK9-specific antibody response and the impact on LDLc were evaluated over a period of 90 weeks. RESULTS: The most common systemic treatment-related adverse events (AEs) reported were fatigue, headache, and myalgia in 75% of subjects in the AT06A group and 58% and 46% of subjects in the placebo and AT04A groups, respectively. Injection site reactions (ISR) representing 63% of all treatment-emergent adverse events (TEAEs), were transient and mostly of mild or moderate intensity and rarely severe (3%). Both active treatments triggered a robust, long-lasting antibody response towards the antigenic peptides used for immunization that optimally cross-reacted with the target epitope on PCSK9. In the AT04A group, a reduction in serum LDLc was observed with a mean peak reduction of 11.2% and 13.3% from baseline compared to placebo at week 20 and 70 respectively, and over the whole study period, the mean LDLc reduction for the AT04A group vs. placebo was -7.2% (95% CI [-10.4 to -3.9], P < 0.0001). In this group, PCSK9 target epitope titers above 50 were associated with clinically relevant LDLc reductions with an individual maximal decrease of 39%. CONCLUSIONS: Although both AT04A and AT06 were safe and immunogenic, only AT04A demonstrated significant LDLc-lowering activity, justifying further development. TRIAL REGISTRATION: EudraCT: 2015-001719-11. ClinicalTrials.gov Identifier: NCT02508896.
Assuntos
Hipercolesterolemia/tratamento farmacológico , Pró-Proteína Convertase 9/imunologia , Vacinas de Subunidades Antigênicas/uso terapêutico , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Método Simples-Cego , Vacinas de Subunidades Antigênicas/administração & dosagem , Vacinas de Subunidades Antigênicas/efeitos adversos , Adulto JovemRESUMO
Personality and dementia are connected in different ways. A broad knowledge about personality and prodromal stages of dementia might be helpful to identify dementia as early as possible. Hence, personality differences between three cognitively impaired groups on the basis of patients' self-assessments of personality traits and connections between personality and cognitive functioning were examined via a cross-sectional study. The sample consisted of cognitively impaired patients (Nâ¯= 133), aged 50 and older, who came to a memory clinic due to cognitive complaints. The test procedure encompassed a cognitive screening, the Neuropsychological Test Battery Vienna (NTBV), and self-assessment questionnaires such as the Big Five Plus One Persönlichkeitsinventar (B5PO). While patients with subjective cognitive decline (SCD) did not differ from those with non-amnestic mild cognitive impairment (naMCI) concerning the different personality traits, patients with amnestic mild cognitive impairment (aMCI) showed significantly lower scores for extraversion (pâ¯< 0.05), openness (pâ¯< 0.001), and empathy (pâ¯< 0.001) than patients with SCD as well as patients with naMCI. Thus, cognitively impaired groups mainly differ concerning personality traits depending on whether they do show memory decline or not.
Assuntos
Disfunção Cognitiva/psicologia , Personalidade , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Humanos , Pessoa de Meia-Idade , Testes NeuropsicológicosRESUMO
A link between Gaucher disease (GD) and Parkinson disease (PD) has been suggested by many studies. Lewy-body-like α-synuclein inclusions have been shown in older GD patients who developed Parkinsonism. It has been proposed that decreased levels of glucocerebrosidase mediate impaired α-synuclein degradation and hence its accumulation. Nevertheless, this phenomenon is less investigated in the infantile form of GD. The aim of the study was to evaluate α-synuclein and τ-pathology in the brain and non-neural tissues (liver, spleen, pancreas, myocardial muscle, and lung) of 5 infants (age range from 1 month to 4 years) with GD. Our immunohistochemical study did not provide evidence that pathological α-synuclein or τ-accumulates early in tissues where Gaucher cells are already prominently present. Although recent finding of altered plasma α-synuclein levels in infantile GD patients suggest an early imbalance of α-synuclein homeostasis, our findings indicate that this does not inevitably coincide with α-synuclein pathology in the brain. Understanding this temporal variance of plasma levels and brain accumulation of α-synuclein might also be important when interpreting blood-based α-synuclein assays for the diagnosis of PD.
Assuntos
Encéfalo/patologia , Doença de Gaucher/patologia , Histiócitos/patologia , alfa-Sinucleína/metabolismo , Pré-Escolar , Feminino , Humanos , Lactente , MasculinoRESUMO
Extrusion of chemotherapeutics by ATP-binding cassette (ABC) transporters like ABCB1 (P-glycoprotein) represents a crucial mechanism of multidrug resistance in cancer therapy. We have previously shown that the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor simvastatin directly inhibits ABCB1, alters the glycosylation of the transporter, and enhances the intracellular accumulation of doxorubicin with subsequent anti-cancer action. Here, we show that simvastatin reduces endogenous dolichol levels and ABCB1 in human neuroblastoma SH-SY5Y cells. Coapplication with dolichol prevents the downregulation of the ABCB1 transporter. Importantly, dolichol also attenuated simvastatin-induced apoptosis, unmasking involvement of unfolded protein response. Direct monitoring of the fluorescent fusion protein YFP-ABCB1 further confirms concentration-dependent reduction of ABCB1 in HEK293 cells by simvastatin. In simvastatin-treated murine xenografts, ABCB1 was also reduced in the liver and rhabdomyosarcoma but did not reach significance in neuroblastoma. Nevertheless, the in vivo anti-cancer effects of simvastatin are corroborated by increased apoptosis in tumor tissues. These findings provide experimental evidence for usage of simvastatin in novel chemotherapeutic regimens and link dolichol depletion to simvastatin-induced anti-cancer activity.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Antineoplásicos/farmacologia , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Sinvastatina/farmacologia , Animais , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Linhagem Celular Tumoral , Dolicóis/farmacologia , Regulação para Baixo , Feminino , Células HEK293 , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Fígado/efeitos dos fármacos , Fígado/metabolismo , Camundongos , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Neoplasias/patologia , Sinvastatina/uso terapêutico , Carga Tumoral/efeitos dos fármacosRESUMO
The interleukin (IL)-6 inhibits the growth of early-stage melanoma cells, but not metastatic cells. Metastatic melanoma cells are susceptible to statin-induced apoptosis, but this is not clear for early-stage melanoma cells. This study aimed to investigate the IL-6 susceptibility of melanoma cells from different stages in the presence of simvastatin to overcome loss of growth arrest. ELISA was used to detect secreted IL-6 in human melanoma cells. The effects of IL-6 were measured by western blots for STAT3 and Bcl-2 family proteins. Apoptosis and proliferation were measured by caspase 3 activity, Annexin V staining, cell cycle analysis, and a wound-healing assay. Human metastatic melanoma cells A375 and 518A2 secrete high amounts of IL-6, in contrast to early-stage WM35 cells. Canonical IL-6 signaling is intact in these cells, documented by transient phosphorylation of STAT3. Although WM35 cells are highly resistant to simvastatin-induced apoptosis, coadministration with IL-6 enhanced the susceptibility to undergo apoptosis. This proapoptotic effect of IL-6 might be explained by a downregulation of Bcl-XL, observed only in WM35 cells. Furthermore, the IL-6 receptor blocking antibody tocilizumab was coadministered and unmasked an IL-6-sensitive proportion in the simvastatin-induced caspase 3 activity of metastatic melanoma cells. These results confirm that simvastatin facilitates apoptosis in combination with IL-6. Although endogenous IL-6 secretion is sufficient in metastatic melanoma cells, exogenously added IL-6 is needed for WM35 cells. This effect may explain the failure of simvastatin to reduce melanoma incidence in clinical trials and meta-analyses.
Assuntos
Anticorpos Monoclonais Humanizados/farmacologia , Apoptose/efeitos dos fármacos , Interleucina-6/metabolismo , Melanoma/patologia , Sinvastatina/farmacologia , Antineoplásicos/farmacologia , Sítios de Ligação/efeitos dos fármacos , Caspase 3/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Melanoma/tratamento farmacológico , Metástase Neoplásica/patologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Fator de Transcrição STAT3/metabolismo , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/patologia , Cicatrização/efeitos dos fármacos , Proteína bcl-X/metabolismoRESUMO
Autosomal dominant familial Alzheimer's disease (AD) is associated with mutations in the AßPP, PSEN1, and PSEN2 genes. The clinical phenotype associated with AßPP mutations is mainly characterized by dementia or by strokes related to cerebral amyloid angiopathy (CAA). We present a comprehensive clinical, neuropathological, genetic, and biochemical study on a patient affected by familial AD associated with the I716F mutation in the AßPP gene. The clinical phenotype was characterized by early age of onset of 47 years, and rapidly progressive cerebellar ataxia, myoclonic jerks, rigidity, and dementia reminiscent of Creutzfeldt-Jakob disease (CJD), followed by a prolonged persistent vegetative state. Neuropathological evaluation of the proband revealed AD-related pathology but also α-synucleinopathy compatible with dementia with Lewy bodies neocortical stage or Parkinson's disease corresponding to Braak stage 6. Tau-pathology in the form of neurofibrillary degeneration corresponded to stage VI according to the Braak classification. The severe Aß pathology included CAA, numerous plaques, and deposition of N-truncated pyroglutamate-modified Aß peptides. Remarkably, pyroglutamate Aß oligomers were also present intracellularly in Purkinje cells corresponding to the ataxic phenotype. The detection of a CJD-like phenotype expands the spectrum of clinical presentations associated with familial AD. Our study supports the concept that the neuropathology of familial AD expands beyond the classical AD-related pathology as defined by plaques and tangles. Finally, we provide evidence for the first time that oligomeric pyroglutamate Aß is present in a specific pattern correlating with the clinical symptoms of a patient with AßPP I716F mutation.
Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Corpos de Lewy/metabolismo , Mutação/genética , alfa-Sinucleína/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Encéfalo/metabolismo , Encéfalo/patologia , Proteínas de Ligação a DNA/metabolismo , Testes Genéticos , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Proteínas tau/metabolismoRESUMO
Tumours, which are initially sensitive to cytotoxic agents, often develop resistance to a broad spectrum of structurally unrelated drugs. The 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors have been shown to inhibit ATP-binding cassette (ABC) transporters but have also impact on glycosylation of such proteins. Doxorubicin is a substrate for ABC transporters like P-glycoprotein (ABCB1) which is present in human RD rhabdomyosarcoma cells. It was therefore the aim of this study to identify the compartmentalisation and action of doxorubicin in simvastatin-treated RD cells. Due to autofluorescence of doxorubicin, intracellular distribution was monitored by confocal microscopy. The biological effects were traced on the level of colony formation, caspase activation and DNA injury. Here we show that simvastatin treatment leads to ABCB1 inhibition and down-regulation of the transporter. Consequently, these cells accumulate significant amounts of doxorubicin, predominantly in the nucleus and lysosomes. While clearance of the anthracycline into lysosomes is not altered by simvastatin treatment, it significantly enhanced nuclear accumulation in a HMG-CoA reductase-independent manner. Thus, in such treated cells, topoisomerase II activity is significantly inhibited, which is further corroborated by augmented double-strand DNA breaks. Moreover, colony formation was synergistically inhibited by the combination of simvastatin and doxorubicin. Given the fact that ABCB1 expression correlates with an adverse prognosis in many tumours, adjuvant chemotherapy including statins might represent a novel therapeutic concept to overcome ABCB1-mediated multidrug resistance by direct inhibition and down-regulation.
Assuntos
Adjuvantes Farmacêuticos/administração & dosagem , Doxorrubicina/administração & dosagem , Inibidores de Hidroximetilglutaril-CoA Redutases/administração & dosagem , Sinvastatina/administração & dosagem , Inibidores da Topoisomerase II/administração & dosagem , Subfamília B de Transportador de Cassetes de Ligação de ATP , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/antagonistas & inibidores , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Caspase 3/metabolismo , Caspase 8/metabolismo , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Quebras de DNA de Cadeia Dupla , DNA Topoisomerases Tipo II/metabolismo , Histonas/metabolismo , Humanos , Ácido Mevalônico/administração & dosagem , Rabdomiossarcoma/metabolismoRESUMO
The development of multidrug resistance (MDR) is a major problem during cancer treatment. Drug efflux via ATP-binding cassette (ABC) transporters is the main mechanism responsible for resistance to chemotherapeutics. We have recently observed that statins enhance susceptibility to doxorubicin-induced apoptosis in human rhabdomyosarcoma cells, which is now also observed in human SH-SY5Y neuroblastoma cells. We have therefore investigated the ABC transporter activity to confirm a possible inhibition by statins in SH-SY5Y cells. Indeed, simvastatin directly inhibited dye transport at equimolar concentrations of the ABC transporter inhibitor, verapamil. Making use of the fluorescence behavior of doxorubicin the accumulation of anthracycline was monitored in real-time confocal microscopy. The intracellular doxorubicin accumulation was immediately enhanced by statins in SH-SY5Y cells and also in a MYCN-amplified neuroblastoma cell line STA-NB-10. The heavily glycosylated P-glycoprotein (ABCB1, P-gp) transporter appeared as a 180-and 140-kDa species. Atorvastatin and simvastatin reduced the 180-kDa form of P-gp, but not verapamil. Thereby the fully glycosylated species is shifted to the core glycosylated species (140 kDa), which was only seen at statin exposure times longer than 24 hr. The functional importance of glycosylation of the transporter was highlighted by exogenous application of N-glycosidase F, which was sufficient to enhance doxorubicin accumulation. Hence, these novel findings of statins' dual impact on P-gp have clinical implications. The enhanced intracellular accumulation of chemotherapeutics or other ABC transporter substrates in the presence of statins may represent a novel concept to overcome MDR in cancer therapy and improve drug safety.