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BACKGROUND: This study focuses on the efficacy and 2-year outcomes of ultra-low-dose radiotherapy (RT) in treating primary and secondary ocular adnexal lymphoma (OAL). METHODS: A retrospective analysis was conducted on patients with OAL between 2017 and 2022, treated with 4 Gy of RT. The primary and secondary outcomes assessed were response rate, progression-free survival, and lymphoma-related death. RESULTS: Twenty-one patients with primary and secondary OAL of diverse, presentations, subtypes, and stages were included. The orbital tumors had an average size of 17 × 16 × 16 mm. Of the 14 primary OAL cases, 3 (14%) had T1N0M0 disease, 8 (38%) T2N0M0, and 3 (14%) T3N0M0 (AJCC 8th edition staging); of the 7 secondary OALs, 4 (19%) were stage IE, 2 (10%) stage IIE, and 1 (5%) stage IIIE (Ann Arbor staging). Ultra-low-dose RT yielded a 95% complete response rate and 100% progression-free survival rates, both locally and systemically at 2 years. Mild dry eyes were reported in 14% of patients as a late treatment toxicity. CONCLUSIONS: Ultra-low-dose RT emerges as an effective and well-tolerated treatment approach for OAL. Our findings support the use of 4 Gy, showcasing high complete response rates (95%) and durable disease control without significant local relapses over an average follow up of 27 months. Our results align with earlier investigations, validating the curative potential of ultra-low-dose RT and reinforcing the concept of achieving favorable outcomes with minimal intervention. This approach may potentially alleviate the burden of long-term ocular side effects associated with higher radiation doses, enhancing the overall quality of life for OAL patients.
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During 1979-2022, Cameroon recorded 32 laboratory-confirmed mpox cases among 137 suspected mpox cases identified by the national surveillance network. The highest positivity rate occurred in 2022, indicating potential mpox re-emergence in Cameroon. Both clade I (n = 12) and clade II (n = 18) monkeypox virus (MPXV) were reported, a unique feature of mpox in Cameroon. The overall case-fatality ratio of 2.2% was associated with clade II. We found mpox occurred only in the forested southern part of the country, and MPXV phylogeographic structure revealed a clear geographic separation among concurrent circulating clades. Clade I originated from eastern regions close to neighboring mpox-endemic countries in Central Africa; clade II was prevalent in western regions close to West Africa. Our findings suggest that MPXV re-emerged after a 30-year lapse and might arise from different viral reservoirs unique to ecosystems in eastern and western rainforests of Cameroon.
Assuntos
Monkeypox virus , Mpox , Humanos , Camarões/epidemiologia , Monkeypox virus/genética , Ecossistema , Mpox/epidemiologia , África Ocidental/epidemiologiaRESUMO
BACKGROUND: Day care units are an essential part of psychiatric treatment in Germany. In rheumatology they are also regularly used. Axial spondylarthritis (axSpA) is an inflammatory rheumatic disease that causes pain, diminished quality of life, limitations in activities of daily living and ability to work, especially if insufficiently treated. The multimodal rheumatologic complex treatment with at least 14 days of inpatient care is an established tool to control exacerbated disease activity. The feasibility and effect of an equivalent treatment in a day care setting has not yet been evaluated. METHODS: The effect of a therapy in a day care unit comparable to the inpatient multimodal rheumatologic complex treatment was investigated using clinically established patient reported outcomes (NAS pain, FFbH, BASDAI, BASFI). RESULTS: Selected subgroups of axSpA patients can routinely and effectively be treated in day care units. Intensified multimodal as well as nonintensified treatment forms lead to reduced disease activity. Additionally, compared to nonintensified treatment, the intensified multimodal treatment approach leads to significantly reduced pain, and disease-related and functional limitations in daily life. CONCLUSION: If available, treatment in a day care unit can complement the established inpatient treatment modalities in selected axSpA patients. In cases with high disease activity and suffering, intensified multimodal treatment should be preferred due to better outcomes.
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Artrite Reumatoide , Espondiloartrite Axial , Espondilartrite , Espondilite Anquilosante , Humanos , Espondilartrite/terapia , Qualidade de Vida , Hospital Dia , Atividades Cotidianas , DorRESUMO
In systemic lupus erythematosus, ophthalmic manifestations are noted in up to one-third of patients. We describe a patient with an unusual initial presentation of this disorder.
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Dacriocistite/diagnóstico , Pálpebras/patologia , Lúpus Eritematoso Sistêmico/diagnóstico , Adulto , Pálpebras/diagnóstico por imagem , Feminino , Humanos , Tomografia Computadorizada por Raios XAssuntos
Imagem Multimodal/métodos , Drusas do Disco Óptico/diagnóstico por imagem , Drusas do Disco Óptico/patologia , Disco Óptico/diagnóstico por imagem , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Imagem Óptica/métodos , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos , Adulto JovemRESUMO
Human p21(Waf1) protein is well known for being transcriptionally induced by p53 and activating the cell cycle checkpoint arrest in response to DNA breaks. Here we report that p21(Waf1) protein undergoes a bimodal regulation, being upregulated in response to low doses of DNA damage but rapidly and transiently degraded in response to high doses of DNA lesions. Responsible for this degradation is the checkpoint kinase Chk1, which phosphorylates p21(Waf1) on T145 and S146 residues and induces its proteasome-dependent proteolysis. The initial p21(Waf1) degradation is then counteracted by the ATM-Chk2 pathway, which promotes the p53-dependent accumulation of p21(Waf1) at any dose of damage. We also found that p21(Waf1) ablation favors the activation of an apoptotic program to eliminate otherwise irreparable cells. These findings support a model in which in human cells a balance between ATM-Chk2-p53 and the ATR-Chk1 pathways modulates p21(Waf1) protein levels in relation to cytostatic and cytotoxic doses of DNA damage.
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Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Dano ao DNA , Apoptose/efeitos dos fármacos , Bleomicina/farmacologia , Linhagem Celular Tumoral , Quinase 1 do Ponto de Checagem , Regulação para Baixo/efeitos dos fármacos , Humanos , Fosforilação/efeitos dos fármacos , Proteínas Quinases/metabolismo , Proteólise/efeitos dos fármacosRESUMO
BACKGROUND: Current treatment strategies for head and neck cancer are associated with significant morbidity and up to 50% of patients relapse, highlighting the need for more specific and effective therapeutics. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) and Smac mimetics (SMs) are promising anticancer agents, but their effect on head and neck squamous cell carcinoma (HNSCC) remains unknown. METHODS: We examined the response of a panel of nine HNSCC cell lines to TRAIL and SMs and investigated the mechanism of cell type-specific response by functional analysis. RESULTS: Head and neck cancer cell lines revealed a converse response pattern with three cell lines being highly sensitive to Smac-164 (SM) but resistant to TRAIL, whereas the other six were sensitive to TRAIL but resistant to SM. Distinct protein expression and activation patterns were found to be associated with susceptibility of HNSCC cell lines to TRAIL and SM. Tumour necrosis factor-related apoptosis-inducing ligand sensitivity was associated with high caspase-8 and Bid protein levels, and TRAIL-sensitive cell lines were killed via the type II extrinsic apoptotic pathway. Smac mimetic-sensitive cells expressed low levels of caspase-8 and Bid but had high TNF-α expression. Smac mimetic-induced cell death was associated with caspase-10 activation, suggesting that in the absence of caspase-8, caspase-10 mediates response to SM. Cotreatment with TNF-α sensitised the resistant cells to SM, demonstrating a decisive role for TNF-α-driven feedback loop in SM sensitivity. CONCLUSIONS: Tumour necrosis factor-related apoptosis-inducing ligand and SMs effectively kill HNSCC cell lines and therefore represent potential targeted therapeutics for head and neck cancer. Distinct molecular mechanisms determine the sensitivity to each agent, with levels of TNF-α, caspase-8, Bid and caspase-10 providing important predictive biomarkers of response to these agents.
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Apoptose/efeitos dos fármacos , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Carcinoma de Células Escamosas/tratamento farmacológico , Caspase 10/metabolismo , Caspase 8/metabolismo , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Ligante Indutor de Apoptose Relacionado a TNF/farmacologia , Triazóis/farmacologia , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/metabolismo , Biomimética , Western Blotting , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patologia , Proliferação de Células/efeitos dos fármacos , Ensaio de Imunoadsorção Enzimática , Neoplasias de Cabeça e Pescoço/metabolismo , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Células Tumorais Cultivadas , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Loss of ataxia telangiectasia mutated (ATM) kinase, a key factor of the DNA damage response (DDR) pathway, causes the cancer predisposing and neurodegenerative syndrome ataxia-telangiectasia (A-T). To investigate the mechanisms of neurodegeneration, we have reprogrammed fibroblasts from ATM-null A-T patients and normal controls to pluripotency (human-induced pluripotent stem cells), and derived from these neural precursor cells able to terminally differentiate into post-mitotic neurons positive to >90% for ß-tubulin III+/microtubule-associated protein 2+. We show that A-T neurons display similar voltage-gated potassium and sodium currents and discharges of action potentials as control neurons, but defective expression of the maturation and synaptic markers SCG10, SYP and PSD95 (postsynaptic density protein 95). A-T neurons exhibited defective repair of DNA double-strand breaks (DSBs) and repressed phosphorylation of ATM substrates (e.g., γH2AX, Smc1-S966, Kap1-S824, Chk2-T68, p53-S15), but normal repair of single-strand breaks, and normal short- and long-patch base excision repair activities. Moreover, A-T neurons were resistant to apoptosis induced by the genotoxic agents camptothecin and trabectedin, but as sensitive as controls to the oxidative agents. Most notably, A-T neurons exhibited abnormal accumulation of topoisomerase 1-DNA covalent complexes (Top1-ccs). These findings reveal that ATM deficiency impairs neuronal maturation, suppresses the response and repair of DNA DSBs, and enhances Top1-cc accumulation. Top1-cc could be a risk factor for neurodegeneration as they may interfere with transcription elongation and promote transcriptional decline.
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Proteínas Mutadas de Ataxia Telangiectasia/deficiência , Ataxia Telangiectasia/enzimologia , Células-Tronco Pluripotentes Induzidas/enzimologia , Neurônios/enzimologia , Ataxia Telangiectasia/genética , Ataxia Telangiectasia/fisiopatologia , Proteínas Mutadas de Ataxia Telangiectasia/genética , Células Cultivadas , Quebras de DNA de Cadeia Dupla , Reparo do DNA , DNA Topoisomerases Tipo I/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Proteínas de Membrana , Mitose , Neurônios/citologia , Fosforilação , EstatminaRESUMO
The rational design, synthesis and in vitro biological evaluation of dual action conjugates 11-13, containing a tumour targeting, integrin αvß3/αvß5 ligand portion and a pro-apoptotic SMAC mimetic portion (cyclo-RGD/SMAC mimetic conjugates) are reported. The binding strength of the two separate units is generally maintained by these dual action conjugates. In particular, the connection between the separate units (anchor points on each unit; nature, length and stability of the linker) influences the activity of each portion against its molecular targets (integrins αvß3/αvß5 for cyclo-RGD, IAP proteins for SMAC mimetics). Each conjugate portion tolerates different substitutions while preserving the binding affinity for each target.
Assuntos
Proteínas Inibidoras de Apoptose/metabolismo , Integrina alfaVbeta3/metabolismo , Proteínas Mitocondriais/metabolismo , Peptídeos Cíclicos/síntese química , Peptídeos Cíclicos/farmacologia , Receptores de Vitronectina/metabolismo , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Biotinilação/efeitos dos fármacos , Bovinos , Linhagem Celular Tumoral , Sistema Livre de Células , Dimerização , Doxorrubicina/farmacologia , Humanos , Concentração Inibidora 50 , Ligantes , Peptídeos Cíclicos/química , Ligação Proteica/efeitos dos fármacos , Vitronectina/metabolismoRESUMO
CONTEXT: Exposure to secondhand smoke (SHS) has been reduced in the USA by banning smoking in public places. These restrictions have not had the same effect on children's exposure to SHS as adults suggesting that children are exposed to SHS in locations not covered by bans, such as private homes and cars. OBJECTIVES: Assess exposure to SHS in the backseat of a stationary vehicle where a child would sit, quantify exposures to fine particulates (PM2.5), polycyclic aromatic hydrocarbons (PAH), carbon monoxide (CO) and nicotine. Estimate the impact on a child's mean daily exposure to PM2.5. METHODS: SHS exposures in stationary vehicles with two different window configurations were monitored. A volunteer smoked three cigarettes in a one-hour period for twenty-two experiments. PM2.5, CO, nicotine and PAH where measured in the backseat of the vehicle. 16 PAH compounds were measured for in gas and particle phases as well as real-time particle phase concentrations. RESULTS: The mean PAH concentration, 1325.1 ng/m(3), was larger than concentrations measured in bars and restaurants were smoking is banned in many countries. We estimate that a child spending only ten minutes in the car with a smoker at the mean PM2.5 concentration measured in the first window configuration--1697 mg/m(3)--will cause a 30% increase to the daily mean PM2.5 personal average of a child. CONCLUSIONS: Estimates made using the measured data and previously reported PM2.5 daily mean concentrations for children in California showing that even short exposure periods are capable of creating large exposure to smoke.
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Poluição do Ar em Ambientes Fechados/análise , Exposição Ambiental/análise , Veículos Automotores , Material Particulado/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Fumar , Poluição por Fumaça de Tabaco/análise , California , Monóxido de Carbono/análise , Criança , Humanos , Nicotina/análise , RestaurantesRESUMO
Smac mimetics (SMs) comprise a class of small molecules that target members of the inhibitor of apoptosis family of pro-survival proteins, whose expression in cancer cells hinders the action of conventional chemotherapeutics. Herein, we describe the activity of SM83, a newly synthesised dimeric SM, in two cancer ascites models: athymic nude mice injected intraperitoneally with IGROV-1 human ovarian carcinoma cells and immunocompetent BALB/c mice injected with murine Meth A sarcoma cells. SM83 rapidly killed ascitic IGROV-1 and Meth A cells in vivo (prolonging mouse survival), but was ineffective against the same cells in vitro. IGROV-1 cells in nude mice were killed within the ascites by a non-apoptotic, tumour necrosis factor (TNF)-dependent mechanism. SM83 administration triggered a rapid inflammatory event characterised by host secretion of TNF, interleukin-1ß and interferon-γ. This inflammatory response was associated with the reversion of the phenotype of tumour-associated macrophages from a pro-tumoural M2- to a pro-inflammatory M1-like state. SM83 treatment was also associated with a massive recruitment of neutrophils that, however, was not essential for the antitumoural activity of this compound. In BALB/c mice bearing Meth A ascites, SM83 treatment was in some cases curative, and these mice became resistant to a second injection of cancer cells, suggesting that they had developed an adaptive immune response. Altogether, these results indicate that, in vivo, SM83 modulates the immune system within the tumour microenvironment and, through its pro-inflammatory action, leads cancer cells to die by necrosis with the release of high-mobility group box-1. In conclusion, our work provides evidence that SMs could be more therapeutically active than expected by stimulating the immune system.
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Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Necrose/induzido quimicamente , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Materiais Biomiméticos/química , Materiais Biomiméticos/farmacologia , Materiais Biomiméticos/uso terapêutico , Western Blotting , Linhagem Celular Tumoral , Células Cultivadas , Feminino , Células HCT116 , Humanos , Imunidade Inata/efeitos dos fármacos , Inflamação/induzido quimicamente , Proteínas Inibidoras de Apoptose , Camundongos , Camundongos Endogâmicos BALB C , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Mucopolysaccharidosis type II (MPSII or Hunter Syndrome) is a lysosomal storage disorder caused by the deficit of iduronate 2-sulfatase (IDS) activity and characterized by progressive systemic and neurological impairment. As the early mechanisms leading to neuronal degeneration remain elusive, we chose to examine the properties of neural stem cells (NSCs) isolated from an animal model of the disease in order to evaluate whether their neurogenic potential could be used to recapitulate the early phases of neurogenesis in the brain of Hunter disease patients. Experiments here reported show that NSCs derived from the subventricular zone (SVZ) of early symptomatic IDS-knockout (IDS-ko) mouse retained self-renewal capacity in vitro, but differentiated earlier than wild-type (wt) cells, displaying an evident lysosomal aggregation in oligodendroglial and astroglial cells. Consistently, the SVZ of IDS-ko mice appeared similar to the wt SVZ, whereas the cortex and striatum presented a disorganized neuronal pattern together with a significant increase of glial apoptotic cells, suggesting that glial degeneration likely precedes neuronal demise. Interestingly, a very similar pattern was observed in the brain cortex of a Hunter patient. These observations both in vitro, in our model, and in vivo suggest that IDS deficit seems to affect the late phases of neurogenesis and/or the survival of mature cells rather than NSC self-renewal. In particular, platelet-derived growth factor receptor-α-positive (PDGFR-α+) glial progenitors appeared reduced in both the IDS-ko NSCs and in the IDS-ko mouse and human Hunter brains, compared with the respective healthy controls. Treatment of mutant NSCs with IDS or PDGF throughout differentiation was able to increase the number of PDGFR-α+ cells and to reduce that of apoptotic cells to levels comparable to wt. This evidence supports IDS-ko NSCs as a reliable in vitro model of the disease, and suggests the rescue of PDGFR-α+ glial cells as a therapeutic strategy to prevent neuronal degeneration.
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Mucopolissacaridose II/metabolismo , Mucopolissacaridose II/patologia , Células-Tronco Neurais/metabolismo , Células-Tronco Neurais/patologia , Doenças Neurodegenerativas/patologia , Neuroglia/metabolismo , Neuroglia/patologia , Animais , Apoptose/genética , Apoptose/fisiologia , Encéfalo/metabolismo , Encéfalo/patologia , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Glicoproteínas/deficiência , Glicoproteínas/genética , Glicoproteínas/metabolismo , Doenças por Armazenamento dos Lisossomos/metabolismo , Doenças por Armazenamento dos Lisossomos/patologia , Camundongos , Camundongos Knockout , Mucopolissacaridose II/genética , Doenças Neurodegenerativas/metabolismoRESUMO
As the U.S. population becomes more racially diverse and different groups move in to previously White-dominated spaces, new techniques of exclusion and marginalization are being employed in an effort to regulate the opportunities and progress available to racialized minority groups. In this article, the author argues that mass media's preoccupation with the Williams sisters' "on-court" play and "off-court" activities constitutes a form of surveillance that is used by Whites to identify, observe, and ultimately, limit the range of available representations of Venus and Serena Williams. The author also suggests that this kind of public scrutiny produces racialized images and narratives constitutive of "race talk," a key manifestation of the new racism(s) characteristic of the politics of this sociohistorical moment.
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Atletas , Negro ou Afro-Americano , Vigilância da População , Opinião Pública , Relações Raciais , Mulheres , Negro ou Afro-Americano/educação , Negro ou Afro-Americano/etnologia , Negro ou Afro-Americano/história , Negro ou Afro-Americano/legislação & jurisprudência , Negro ou Afro-Americano/psicologia , Atletas/educação , Atletas/história , Atletas/legislação & jurisprudência , Atletas/psicologia , História do Século XX , História do Século XXI , Humanos , Opinião Pública/história , Relações Raciais/história , Relações Raciais/legislação & jurisprudência , Relações Raciais/psicologia , Mudança Social/história , Estados Unidos/etnologia , Mulheres/educação , Mulheres/história , Mulheres/psicologiaRESUMO
BACKGROUND: XIAP (X-linked inhibitor of apoptosis protein) is an anti-apoptotic protein exerting its activity by binding and suppressing caspases. As XIAP is overexpressed in several tumours, in which it apparently contributes to chemoresistance, and because its activity in vivo is antagonised by second mitochondria-derived activator of caspase (SMAC)/direct inhibitor of apoptosis-binding protein with low pI, small molecules mimicking SMAC (so called SMAC-mimetics) can potentially overcome tumour resistance by promoting apoptosis. METHODS: Three homodimeric compounds were synthesised tethering a monomeric SMAC-mimetic with different linkers and their affinity binding for the baculoviral inhibitor repeats domains of XIAP measured by fluorescent polarisation assay. The apoptotic activity of these molecules, alone or in combination with tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) and/or Bortezomib, was tested in melanoma cell lines by MTT viability assays and western blot analysis of activated caspases. RESULTS: We show that in melanoma cell lines, which are typically resistant to chemotherapeutic agents, XIAP knock-down sensitises cells to TRAIL treatment in vitro, also favouring the accumulation of cleaved caspase-8. We also describe a new series of 4-substituted azabicyclo[5.3.0]alkane monomeric and dimeric SMAC-mimetics that target various members of the IAP family and powerfully synergise at submicromolar concentrations with TRAIL in inducing cell death. Finally, we show that the simultaneous administration of newly developed SMAC-mimetics with Bortezomib potently triggers apoptosis in a melanoma cell line resistant to the combined effect of SMAC-mimetics and TRAIL. CONCLUSION: Hence, the newly developed SMAC-mimetics effectively synergise with TRAIL and Bortezomib in inducing cell death. These findings warrant further preclinical studies in vivo to verify the anticancer effectiveness of the combination of these agents.
Assuntos
Ácidos Borônicos/farmacologia , Morte Celular/efeitos dos fármacos , Peptídeos e Proteínas de Sinalização Intracelular/farmacologia , Melanoma/tratamento farmacológico , Proteínas Mitocondriais/farmacologia , Pirazinas/farmacologia , Ligante Indutor de Apoptose Relacionado a TNF/farmacologia , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/metabolismo , Proteínas Reguladoras de Apoptose , Bortezomib , Caspase 8/metabolismo , Linhagem Celular Tumoral , Regulação para Baixo , Interações Medicamentosas , Sinergismo Farmacológico , Técnicas de Silenciamento de Genes , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/administração & dosagem , Proteínas Mitocondriais/administração & dosagem , Ligante Indutor de Apoptose Relacionado a TNF/administração & dosagemRESUMO
Ataxia-telangiectasia (A-T) is a neurodegenerative disorder caused by defects in the ATM kinase, a component of the DNA-damage response (DDR). Here, we employed an immortalized human neural stem-cell line (ihNSC) capable of differentiating in vitro into neurons, oligodendrocytes and astrocytes to assess the ATM-dependent response and outcome of ATM ablation. The time-dependent differentiation of ihNSC was accompanied by an upregulation of ATM and DNA-PK, sharp downregulation of ATR and Chk1, transient induction of p53 and by the onset of apoptosis in a fraction of cells. The response to ionizing radiation (IR)-induced DNA lesions was normal, as attested by the phosphorylation of ATM and some of its substrates (e.g., Nbs1, Smc1, Chk2 and p53), and by the kinetics of gamma-H2AX nuclear foci formation. Depletion in these cells of ATM by shRNA interference (shATM) attenuated the differentiation-associated apoptosis and response to IR, but left unaffected the growth, self-renewal and genomic stability. shATM cells generated a normal number of MAP2/beta-tubulin III+ neurons, but a reduced number of GalC+ oligodendrocytes, which were nevertheless more susceptible to oxidative stress. Altogether, these findings highlight the potential of ihNSCs as an in vitro model system to thoroughly assess, besides ATM, the role of DDR genes in neurogenesis and/or neurodegeneration.
Assuntos
Proteínas de Ciclo Celular/metabolismo , Diferenciação Celular , Dano ao DNA , Proteínas de Ligação a DNA/metabolismo , Neuroglia/citologia , Neurônios/citologia , Proteínas Serina-Treonina Quinases/metabolismo , Células-Tronco/citologia , Proteínas Supressoras de Tumor/metabolismo , Astrócitos/citologia , Astrócitos/metabolismo , Proteínas Mutadas de Ataxia Telangiectasia , Proteínas de Ligação ao Cálcio/metabolismo , Linhagem Celular , Sobrevivência Celular , Quinase 1 do Ponto de Checagem , Proteínas de Ligação a DNA/deficiência , Técnicas de Silenciamento de Genes , Histonas/metabolismo , Humanos , Neurônios/metabolismo , Oligodendroglia/citologia , Oligodendroglia/metabolismo , Proteínas Quinases/metabolismo , Proteínas Serina-Treonina Quinases/deficiência , Interferência de RNA , Radiação Ionizante , Células-Tronco/metabolismo , Fatores de Tempo , Proteína Supressora de Tumor p53/metabolismo , Proteínas Supressoras de Tumor/deficiênciaRESUMO
Effects of auditory deprivation on speech production by ten cochlear-implanted children were investigated by turning off the implant for durations ranging from 0.3 to 5.0 s and measuring the formant frequencies (F1 and F2) of the vowel /epsilon/. In five of the ten talkers, F1 and/or F2 shifted when auditory feedback was eliminated. Without feedback, F2 frequency lowered consistently, suggesting vowel centralization. Phonetic transcription indicated that some of these acoustic changes led to perceptible shifts in phonetic quality. The results provide evidence that brief periods of auditory deprivation can produce perceptible changes in vowels produced by some cochlear-implanted children.
Assuntos
Estimulação Acústica , Implantes Cocleares , Surdez/reabilitação , Retroalimentação , Fonética , Percepção da Fala , Medida da Produção da Fala , Adolescente , Criança , Feminino , Humanos , Masculino , Inteligibilidade da FalaRESUMO
Fanconi anemia (FA) is an autosomal recessive disease characterized by pancitopenia, congenital malformations, predisposition to cancers and chromosomal instability. We report the clinical and molecular features of a patient initially identified as a potential FA case only because of chemotherapy toxicity during the treatment of a T-lineage acute lymphoblastic leukemia (ALL). Cells from this patient showed a moderate chromosomal instability, increasing sensitivity to DNA crosslinking agents but normal response to ionizing radiation. The analysis of FA proteins demonstrated a marked reduction of FANCD2 (>95%), but normal levels of FANCA or FANCG. Interestingly, this defect was associated with a homozygous missense mutation of FANCD2, resulting in a novel amino-acid substitution (Leu153Ser) at residue Leu153, which is highly conserved through evolution. The FANCD2(L153S) protein, whose reduced expression was not due to impaired transcription, was detected also in its monoubiquitinated form in the nucleus, suggesting that the mutation does not affect post-translation modifications or subcellular localization but rather the stability of FANCD2. Therefore, the hypomorphic Leu153Ser mutation represents the first example of a FANCD2 defect that might promote clonal progression of tumors, such as T-ALL, and severe chemotherapy toxicity in patients without any clinical manifestations typical of FA.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Proteína do Grupo de Complementação D2 da Anemia de Fanconi/genética , Leucemia-Linfoma de Células T do Adulto/tratamento farmacológico , Leucemia-Linfoma de Células T do Adulto/genética , Mutação , Substituição de Aminoácidos , Antígenos CD , Antígenos de Diferenciação Mielomonocítica , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Antígenos CD13 , Criança , Instabilidade Cromossômica , Progressão da Doença , Anemia de Fanconi/genética , Humanos , Infecções/etiologia , Infecções/genética , Leucemia-Linfoma de Células T do Adulto/fisiopatologia , Masculino , Pancitopenia/induzido quimicamente , Pancitopenia/genética , Indução de Remissão , Lectina 3 Semelhante a Ig de Ligação ao Ácido SiálicoRESUMO
The proteasome inhibitor PSI is potently cytotoxic in vitro against human chronic myeloid leukemia (CML) and acute myeloid leukemias (AML). Here, we have tested proteasome inhibitor I (PSI) in a panel of 11 human multiple myeloma (MM) cell lines and found that it has antiproliferative activity, with an IC50 between 4.5 and 557 nM at 48 h. PSI potentiated the toxicity of a number of chemotherapeutic agents in myeloid leukemia but not in MM cell lines, while in combination with therapeutic proteasome inhibitor PS-341 (Bortezomib) it had a synergistic effect. PSI suppressed the growth of AML cell lines more effectively than PS-341. CFU-GM colony assays revealed that CD34+ bone marrow progenitors from CML and AML patients were more sensitive to PSI than those from normal subjects (IC50: 5, 15 and 50 nM for AML, CML and normal, respectively). Moreover, the growth of normal primitive progenitors (LTC-IC) was unaffected by 15 nM PSI (P=0.576). PSI-induced cell death required RNA transcription and protein synthesis, but not DNA replication, was accompanied by the upregulation of Bcl-2 and modest reduction of Bax and Bcl-XL proteins, and involved the activation of caspases 2, 3, 7 and 8. These findings lend additional support to preclinical investigations with PSI.
Assuntos
Inibidores de Cisteína Proteinase/farmacologia , Leucemia Mieloide/tratamento farmacológico , Mieloma Múltiplo/tratamento farmacológico , Oligopeptídeos/farmacologia , Antineoplásicos/farmacologia , Caspases/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sinergismo Farmacológico , Regulação Neoplásica da Expressão Gênica , Humanos , Concentração Inibidora 50 , Leucemia Mieloide/patologia , Mieloma Múltiplo/patologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-bcl-2/genética , Transcrição Gênica , Células Tumorais CultivadasRESUMO
Physical interaction between CDKN2A/p16 and CDK4 proteins regulates the cell cycle progression through the G1 phase and dysfunction of these proteins by gene mutation is implicated in genetic predisposition to melanoma. We analysed 15 Italian melanoma families for germ line mutations in the coding region of the CDKN2A gene and exon 2 of the CDK4 gene. One novel disease-associated mutation (P48T), 3 known pathological mutations (R24P, G101W and N71S) and 2 common polymorphisms (A148T and Nt500 G>C) were identified in the CDKN2A gene. In a family harbouring the R24P mutation, an intronic variant (IVS1, +37 G>C) of uncertain significance was detected in a non-carrier melanoma case. The overall incidence of CDKN2A mutations was 33.3%, but this percentage was higher in families with 3 or more melanoma cases (50%) than in those with only 2 affected relatives (25%). Noteworthy, functional analysis established that the novel mutated protein, while being impaired in cell growth and inhibition assays, retains some in vitro binding to CDK4/6. No variant in the p16-binding region of CDK4 was identified in our families. Our results, obtained in a heterogeneous group of families, support the view that inactivating mutations of CDKN2A contribute to melanoma susceptibility more than activating mutations of CDK4 and that other genetic factors must be responsible for melanoma clustering in a high proportion of families. In addition, they indicate the need for a combination of functional assays to determine the pathogenetic nature of new CDKN2A mutations.
Assuntos
Inibidor p16 de Quinase Dependente de Ciclina/genética , Quinases Ciclina-Dependentes/genética , Mutação em Linhagem Germinativa , Melanoma/genética , Proteínas Proto-Oncogênicas , Neoplasias Cutâneas/genética , Adulto , Idoso , Ciclo Celular , Divisão Celular , Quinase 4 Dependente de Ciclina , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Quinases Ciclina-Dependentes/metabolismo , Análise Mutacional de DNA , DNA de Neoplasias/análise , Suscetibilidade a Doenças , Éxons , Feminino , Fase G1 , Ligação Genética , Testes Genéticos , Humanos , Itália/epidemiologia , Masculino , Pessoa de Meia-Idade , Linhagem , Reação em Cadeia da Polimerase , Polimorfismo Conformacional de Fita Simples , Transcrição GênicaRESUMO
The checkpoint kinase Chk2 has a key role in delaying cell cycle progression in response to DNA damage. Upon activation by low-dose ionizing radiation (IR), which occurs in an ataxia telangiectasia mutated (ATM)-dependent manner, Chk2 can phosphorylate the mitosis-inducing phosphatase Cdc25C on an inhibitory site, blocking entry into mitosis, and p53 on a regulatory site, causing G(1) arrest. Here we show that the ATM-dependent activation of Chk2 by gamma- radiation requires Nbs1, the gene product involved in the Nijmegen breakage syndrome (NBS), a disorder that shares with AT a variety of phenotypic defects including chromosome fragility, radiosensitivity, and radioresistant DNA synthesis. Thus, whereas in normal cells Chk2 undergoes a time-dependent increased phosphorylation and induction of catalytic activity against Cdc25C, in NBS cells null for Nbs1 protein, Chk2 phosphorylation and activation are both defective. Importantly, these defects in NBS cells can be complemented by reintroduction of wild-type Nbs1, but neither by a carboxy-terminal deletion mutant of Nbs1 at amino acid 590, unable to form a complex with and to transport Mre11 and Rad50 in the nucleus, nor by an Nbs1 mutated at Ser343 (S343A), the ATM phosphorylation site. Chk2 nuclear expression is unaffected in NBS cells, hence excluding a mislocalization as the cause of failed Chk2 activation in Nbs1-null cells. Interestingly, the impaired Chk2 function in NBS cells correlates with the inability, unlike normal cells, to stop entry into mitosis immediately after irradiation, a checkpoint abnormality that can be corrected by introduction of the wild-type but not the S343A mutant form of Nbs1. Altogether, these findings underscore the crucial role of a functional Nbs1 complex in Chk2 activation and suggest that checkpoint defects in NBS cells may result from the inability to activate Chk2.