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1.
Cell Death Dis ; 4: e925, 2013 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-24263099

RESUMO

Inhibition of the proteasome is considered as a promising strategy to sensitize cancer cells to apoptosis. Recently, we demonstrated that the proteasome inhibitor Bortezomib primes neuroblastoma cells to TRAIL-induced apoptosis. In the present study, we investigated whether Bortezomib increases chemosensitivity of neuroblastoma cells. Unexpectedly, we discover an antagonistic interaction of Bortezomib and microtubule-interfering drugs. Bortezomib significantly attenuates the loss of cell viability and induction of apoptosis on treatment with Taxol and different vinca alkaloids but not with other chemotherapeutics, that is, Doxorubicin and Cisplatinum. Importantly, Bortezomib inhibits G2/M transition by inhibiting proteasomal degradation of cell cycle regulatory proteins such as p21, thereby preventing cells to enter mitosis, the cell cycle phase in which they are most vulnerable to antitubulin chemotherapeutics. Consequently, Bortezomib counteracts Taxol-induced mitotic arrest and polyploidy, as shown by reduced expression of PLK1 and phosphorylated histone H3. In addition, Bortezomib antagonizes Taxol-mediated degradation of MCL-1 during mitotic arrest by preventing cells to enter mitosis and by inhibiting the proteasome. Downregulation of MCL-1 is critically required for Taxol-induced apoptosis, as overexpression of a phosphomutant MCL-1 variant, which is resistant to degradation, significantly diminishes Taxol-triggered apoptosis. Vice versa, attenuation of Bortezomib-mediated accumulation of MCL-1 by knockdown of MCL-1 significantly enhances Taxol/Bortezomib-induced apoptosis. Thus, Bortezomib rescues Taxol-induced apoptosis by inhibiting G2/M transition and mitigating MCL-1 degradation. The identification of this antagonistic interaction of Bortezomib and microtubule-targeted drugs has important implications for the design of Bortezomib-based combination therapies.


Assuntos
Ácidos Borônicos/farmacologia , Microtúbulos/metabolismo , Pirazinas/farmacologia , Apoptose/efeitos dos fármacos , Western Blotting , Bortezomib , Ciclo Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Fase G2/efeitos dos fármacos , Humanos , Imunoprecipitação , Microtúbulos/efeitos dos fármacos
2.
Oncogene ; 30(4): 494-503, 2011 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-20856197

RESUMO

We recently identified activation of phosphatidylinositol 3'-kinase (PI3K)/Akt as a novel predictor of poor outcome in neuroblastoma. Here, we investigated the effect of small-molecule PI3K inhibitors on chemosensitivity. We provide first evidence that PI3K inhibitors, for example PI103, synergize with various chemotherapeutics (Doxorubicin, Etoposide, Topotecan, Cisplatin, Vincristine and Taxol) to trigger apoptosis in neuroblastoma cells (combination index: high synergy). Mechanistic studies reveal that PI103 cooperates with Doxorubicin to reduce Mcl-1 expression and Bim(EL) phosphorylation and to upregulate Noxa and Bim(EL) levels. This shifted ratio of pro- and antiapoptotic Bcl-2 proteins results in increased Bax/Bak conformational change, loss of mitochondrial membrane potential, cytochrome c release, caspase activation and caspase-dependent apoptosis. Although Mcl-1 knockdown enhances Doxorubicin- and PI103-induced apoptosis, silencing of Noxa, Bax/Bak or p53 reduces apoptosis, underscoring the functional relevance of the Doxorubicin- and PI103-mediated modulation of these proteins for chemosensitization. Bcl-2 overexpression inhibits Bax activation, mitochondrial perturbations, cleavage of caspases and Bid, and apoptosis, confirming the central role of the mitochondrial pathway for chemosensitization. Interestingly, the broad-range caspase inhibitor zVAD.fmk does not interfere with Bax activation or mitochondrial outer membrane permeabilization, whereas it blocks caspase activation and apoptosis, thus placing mitochondrial events upstream of caspase activation. Importantly, PI103 and Doxorubicin cooperate to induce apoptosis and to suppress tumor growth in patients' derived primary neuroblastoma cells and in an in vivo neuroblastoma model, underlining the clinical relevance of the results. Thus, targeting PI3K presents a novel and promising strategy to sensitize neuroblastoma cells for chemotherapy-induced apoptosis, which has important implications for the development of targeted therapies for neuroblastoma.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias Encefálicas/metabolismo , Inibidores Enzimáticos/farmacologia , Neuroblastoma/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/efeitos dos fármacos , Apoptose/fisiologia , Western Blotting , Neoplasias Encefálicas/tratamento farmacológico , Linhagem Celular Tumoral , Separação Celular , Doxorrubicina/farmacologia , Sinergismo Farmacológico , Citometria de Fluxo , Furanos/farmacocinética , Humanos , Imunoprecipitação , Mitocôndrias/efeitos dos fármacos , Neuroblastoma/tratamento farmacológico , Inibidores de Fosfoinositídeo-3 Quinase , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Piridinas/farmacocinética , Pirimidinas/farmacocinética , RNA Interferente Pequeno , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Transfecção
3.
Klin Monbl Augenheilkd ; 223(3): 217-24, 2006 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-16552654

RESUMO

BACKGROUND: Wavefront-guided LASIK-treatments should reduce high-order aberrations (HOA). However, both the microkeratome cut as well as the ablation itself induce HOA. The purpose of this study was to investigate the amount of corrected preoperative measured HOA and induction of new HOA. METHODS: In this retrospective study 67 eyes of 45 myopic patients (- 2 to - 8.1 D SE; spherical equivalent) were treated by standard and wavefront-guided LASIK (Keracor 217z). Pre- and postoperative measurements of total aberrations and contrast sensitivity were performed. The follow-up time was 5.7 +/- 0.9 months. RESULTS: Patients with preoperative increased aberrations of 3rd and 4th order and myopia up to 5 D showed a slightly reduction of wavefront deformation. Cases of higher myopic corrections and lower preoperative spherical aberrations developed an increase of spherical aberrations after LASIK. The changes of other HOA showed no correlation with the amount of corrected myopia. Up to - 5 D patients showed the trend to better postoperative contrast sensitivity under 3 and 85 cd/m (2) after wavefront-guided LASIK than after standard LASIK. A significant advantage of wavefront-guided LASIK can be detected under a spatial frequency of 3 CPD (cycles per degree) and 85 cd/m (2). No advantages of any treatment procedure were shown after higher myopic corrections. CONCLUSION: If preoperative aberrations of 3rd and 4th order were increased and the myopia is < 5 D (SE) -- wavefront-guided LASIK can reduce total ocular HOA. Aberrometric findings after wavefront-guided LASIK in patients with lower preoperative HOA and myopia > 5 D (SE) are comparable with the results after standard treatment.


Assuntos
Sensibilidades de Contraste/fisiologia , Ceratomileuse Assistida por Excimer Laser In Situ/métodos , Miopia/cirurgia , Complicações Pós-Operatórias/etiologia , Refração Ocular/fisiologia , Acuidade Visual/fisiologia , Topografia da Córnea/métodos , Seguimentos , Humanos , Miopia/fisiopatologia , Complicações Pós-Operatórias/fisiopatologia , Complicações Pós-Operatórias/terapia , Estudos Retrospectivos , Resultado do Tratamento
4.
Antimicrob Agents Chemother ; 47(9): 2770-4, 2003 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12936972

RESUMO

A randomized, double-blind, multicenter study of adults with acute bacterial sinusitis (ABS) compared the efficacy and safety of two azithromycin (AZM) regimens, 500 mg/day once daily for 3 days (AZM-3) or 6 days (AZM-6) to the efficacy and safety of an amoxicillin-clavulanate (AMC) regimen of 500-125 mg three times daily for 10 days. A total of 936 subjects with clinically and radiologically documented ABS were treated (AZM-3, 312; AZM-6, 311; AMC, 313). Clinical success rates were equivalent among per-protocol subjects at the end of therapy (AZM-3, 88.8%; AZM-6, 89.3%; AMC, 84.9%) and at the end of the study (AZM-3, 71.7%; AZM-6, 73.4%; AMC, 71.3%). Subjects treated with AMC reported a higher incidence of treatment-related adverse events (AE) (51.1%) than AZM-3 (31.1%, P < 0.001) or AZM-6 (37.6%, P < 0.001). More AMC subjects discontinued the study (n = 28) than AZM-3 (n = 7) and AZM-6 (n = 11) subjects. Diarrhea was the most frequent treatment-related AE. AZM-3 and AZM-6 were each equivalent in efficacy and better tolerated than AMC for ABS.


Assuntos
Combinação Amoxicilina e Clavulanato de Potássio/uso terapêutico , Antibacterianos/uso terapêutico , Azitromicina/uso terapêutico , Quimioterapia Combinada/uso terapêutico , Sinusite/tratamento farmacológico , Doença Aguda , Adulto , Combinação Amoxicilina e Clavulanato de Potássio/administração & dosagem , Combinação Amoxicilina e Clavulanato de Potássio/efeitos adversos , Antibacterianos/administração & dosagem , Antibacterianos/efeitos adversos , Azitromicina/administração & dosagem , Azitromicina/efeitos adversos , Método Duplo-Cego , Quimioterapia Combinada/administração & dosagem , Quimioterapia Combinada/efeitos adversos , Feminino , Humanos , Masculino , Cooperação do Paciente , Sinusite/microbiologia , Resultado do Tratamento
5.
Clin Infect Dis ; 35(6): 760-2, 2002 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-12203175

RESUMO

We compared seminal plasma pharmacokinetic data for the investigational amprenavir prodrug GW433908 with those for amprenavir and an amprenavir-ritonavir combination regimen. All 3 regimens resulted in detectable blood plasma and seminal plasma concentrations of amprenavir. The majority of these concentrations were greater than the plasma protein-corrected 50% inhibitory concentration for wild-type human immunodeficiency virus type 1.


Assuntos
Fármacos Anti-HIV/sangue , Infecções por HIV/sangue , Organofosfatos , Sulfonamidas/sangue , Adulto , Carbamatos , Química Farmacêutica , Furanos , Inibidores da Protease de HIV/sangue , HIV-1/efeitos dos fármacos , Humanos , Masculino , Pró-Fármacos/farmacocinética , Ritonavir/sangue , Sêmen/metabolismo
6.
Bull Entomol Res ; 91(5): 369-87, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11583600

RESUMO

After the recent introduction of the pest whitefly Bemisia tabaci (Gennadius) biotype B into Australia, research was undertaken to study the parasitoids of the long established native B. tabaci and Trialeurodes vaporariorum (Westwood). The genus Encarsia contains species which are important biological control agents of whiteflies and hard scales. The taxonomy of the Encarsia species attacking B. tabaci and T. vaporariorum in Australia and the Pacific Islands is revised. DNA sequencing of the 28S D2 ribosomal DNA was used to characterize species. Sixteen species are recognized, with 12 occurring in Australia, eight in the Pacific region, and four in both regions. All except one species (E. formosa Gahan) are new records for Australia. Four species are described as new from Australia: E. accenta Schmidt & Naumann sp. n., E. adusta Schmidt & Naumann sp. n., E. oakeyensis Schmidt & Naumann sp. n., and E. ustulata Schmidt & Naumann sp. n. Diagnostic descriptions are given for all species and each species is illustrated. A pictorial key is provided to allow the identification of species by non-specialists.


Assuntos
Hemípteros/parasitologia , Vespas/classificação , Animais , Austrália , Feminino , Masculino , Ilhas do Pacífico , Vespas/anatomia & histologia
7.
Eur J Hum Genet ; 8(6): 455-9, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10878667

RESUMO

Segmental neurofibromatosis (NF) is generally thought to result from a postzygotic NF1 (neurofibromatosis type 1) gene mutation. However, this has not yet been demonstrated at the molecular level. Using fluorescence in situ hybridisation (FISH) we identified an NF1 microdeletion in a patient with segmental NF in whom café-au-lait spots and freckles are limited to a single body region. The mutant allele was present in a mosaic pattern in cultured fibroblasts from a café-au-lait spot lesion, but was absent in fibroblasts from normal skin as well as in peripheral blood leukocytes. These findings prove the hypothesis that the molecular basis of segmental cutaneous NF is a mutation in the NF1 gene and that the regional distribution of manifestations reflects different cell clones, commensurate with the concept of somatic mosaicism.


Assuntos
Deleção de Genes , Mosaicismo , Proteínas do Tecido Nervoso/genética , Neurofibromatoses/genética , Adolescente , Humanos , Hibridização in Situ Fluorescente , Masculino , Mutação , Neurofibromina 1 , Fenótipo
8.
Genomics ; 66(1): 93-7, 2000 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-10843809

RESUMO

Large deletions of the NF1 locus occur in 5 to 10% of patients with neurofibromatosis and are commonly associated with specific additional abnormalities characterized by mental retardation, dysmorphic features, and intellectual impairment. To characterize the extent of codeleted genes we constructed a long-range physical BAC/PAC map around the NF1 locus between D17S117 and D17S57 and determined the deletion boundaries in seven unrelated patients. Surprisingly, the proximal and distal breakpoints in five of seven patients fall at almost identical positions, resulting in the loss of at least 11 functional genes. Five of six patients investigated showed a de novo deletion on the maternally derived chromosome. Since D17S117 and D17S57 were previously reported as the outer limits for the great majority of NF1 deletions, we suggest that most NF1 patients with deletion of the entire NF1 gene are hemizygous for the same set of at least 10 additional genes, including SHGC-37343, SHGC-2390, SHGC-34232, OMG, EVI2B, EVI2A, WI-9521, WI-6742, SHGC-34334, and KIAA0160, and thus present with a relatively uniform clinical phenotype.


Assuntos
Deleção de Genes , Proteínas do Tecido Nervoso/genética , Técnicas de Cultura de Células , Quebra Cromossômica , Cromossomos Humanos Par 17 , Mapeamento de Sequências Contíguas , Citogenética , Éxons , Etiquetas de Sequências Expressas , Saúde da Família , Haplótipos , Humanos , Dados de Sequência Molecular , Neurofibromatoses/genética , Neurofibromatoses/patologia , Neurofibromina 1 , Fenótipo , Mapeamento Físico do Cromossomo , Sitios de Sequências Rotuladas
9.
Artigo em Alemão | MEDLINE | ID: mdl-10326234

RESUMO

In dairy goats there is less evidence for relationships between udder form traits, results of physical udder examinations and mastitis indicators in the milk than in dairy cows. In 413 goats (predominantly Weisse Deutsche Edelziege and Bunte Deutsche Edelziege) from five herds (free from C.A.E.) repeated investigations of 2537 udder halves and fore milk samples were carried out in order to compare udder traits with findings in the milk. Less than 20% positive bacteriological findings and a low incidence of clinical mastitis testified a good clinical udder health status of the herds. Small teat-floor distances, loose hanging of the udders and bottle-shaped teats, findings which tended to become more frequent as lactation and lactation numbers progressed, indurative alterations of the mammary tissues and the teats tended to be connected with higher milk cell counts (> 1 million/microliter), more polymorphonuclear milk cells (> 40%), higher electrical milk conductivity (> 6.8 mS/cm) and lower milk lactose content (< 4.6%). A similar effect had a bad state of foot trimming. It is proposed to include the studied udder traits into herd health programs and breeding schemes for goats.


Assuntos
Glândulas Mamárias Animais/fisiologia , Leite/citologia , Leite/microbiologia , Animais , Contagem de Células , Condutividade Elétrica , Feminino , Cabras , Lactose/análise , Glândulas Mamárias Animais/anatomia & histologia , Leite/química , Neutrófilos/citologia , Palpação/veterinária , Exame Físico/veterinária
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