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2.
Ophthalmologica ; 241(2): 61-72, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30153664

RESUMO

PURPOSE: Currently, no outcome measures are clinically validated and accepted as clinical endpoints by regulatory agencies for drug development in intermediate age-related macular degeneration (iAMD). The MACUSTAR Consortium, a public-private research group funded by the European Innovative Medicines Initiative intends to close this gap. PROCEDURES: Development of study protocol and statistical analysis plan including predictive modelling of multimodal endpoints based on a review of the literature and expert consensus. RESULTS: This observational study consists of a cross-sectional and a longitudinal part. Functional outcome measures assessed under low contrast and low luminance have the potential to detect progression of visual deficit within iAMD and to late AMD. Structural outcome measures will be multimodal and investigate topographical relationships with function. Current patient-reported outcome measures (PROMs) are not acceptable to regulators and may not capture the functional deficit specific to iAMD with needed precision, justifying development of novel PROMs for iAMD. The total sample size will be n = 750, consisting mainly of subjects with iAMD (n = 600). CONCLUSIONS: As clinical endpoints currently accepted by regulators cannot detect functional loss or patient-relevant impact in iAMD, we will clinically validate novel candidate endpoints for iAMD.


Assuntos
Gerenciamento Clínico , Angiofluoresceinografia/métodos , Degeneração Macular/diagnóstico , Medidas de Resultados Relatados pelo Paciente , Retina/diagnóstico por imagem , Tomografia de Coerência Óptica/métodos , Acuidade Visual , Fundo de Olho , Humanos , Degeneração Macular/fisiopatologia , Retina/fisiopatologia
3.
Euro Surveill ; 23(4)2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29382413

RESUMO

Seven cases of urogenital schistosomiasis occurred in Corsica in 2015 and 2016. The episodes were related to exposure to the same river and involved the same parasite strain as an outbreak with 106 cases in summer 2013. The connection calls for further investigations on the presence of an animal reservoir and the survival of infested snails during winter. However, recontamination of the river from previously infected bathers remains the most likely hypothesis.


Assuntos
Bulinus/parasitologia , Schistosoma haematobium/isolamento & purificação , Schistosoma/isolamento & purificação , Esquistossomose Urinária/transmissão , Animais , Notificação de Doenças , Monitoramento Ambiental , Água Doce , Humanos , Schistosoma haematobium/genética , Esquistossomose Urinária/parasitologia , Esquistossomose Urinária/urina , Caramujos/parasitologia
4.
Invest Ophthalmol Vis Sci ; 64(13): 42, 2023 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-37883093

RESUMO

Purpose: To assess the progression in functional and structural measures over a five-year period in patients with retinal dystrophy caused by RLBP1 gene mutation. Methods: This prospective, noninterventional study included patients with biallelic RLBP1 mutations from two clinical sites in Sweden and Canada. Key assessments included ocular examinations, visual functional measures (best-corrected visual acuity [BCVA], contrast sensitivity [CS], dark-adaptation [DA] kinetics up to six hours for two wavelengths [450 and 632 nm], Humphrey visual fields [HVF], full-field flicker electroretinograms), and structural ocular assessments. Results: Of the 45 patients enrolled, 38 completed the full five years of follow-up. At baseline, patients had BCVA ranging from -0.2 to 1.3 logMAR, poor CS, HVF defects, and prominent thinning in central foveal thickness. All patients had extremely prolonged DA rod recovery of approximately six hours at both wavelengths. The test-retest repeatability was high across all anatomic and functional endpoints. Cross-sectionally, poorer VA was associated with older age (right eye, correlation coefficient [CC]: 0.606; left eye, CC: -0.578; P < 0.001) and HVF MD values decreased with age (right eye, CC: -0.672, left eye, CC: -0.654; P < 0.001). However, no major changes in functional or structural measures were noted longitudinally over the five-year period. Conclusions: This natural history study, which is the first study to monitor patients with RLBP1 RD for five years, showed that severely delayed DA sensitivity recovery, a characteristic feature of this disease, was observed in all patients across all age groups (17-69 years), making it a potentially suitable efficacy assessment for gene therapy treatment in this patient population.


Assuntos
Distrofias Retinianas , Retinose Pigmentar , Humanos , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Idoso , Estudos Prospectivos , Campos Visuais , Acuidade Visual , Retinose Pigmentar/diagnóstico , Retinose Pigmentar/genética
5.
Am J Ophthalmol ; 239: 180-189, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35247334

RESUMO

PURPOSE: To evaluate whether topical acrizanib (LHA510), a small-molecule vascular endothelial growth factor receptor inhibitor, could suppress the need for anti-vascular endothelial growth factor therapy over a 12-week period in patients with neovascular age-related macular degeneration. DESIGN: A phase 2 multicenter randomized double-masked, vehicle-controlled proof-of-concept study. METHODS: Trial includes n = 90 patients with active choroidal neovascularization due to neovascular age-related macular degeneration and under anti-vascular endothelial growth factor treatment. All patients received an intravitreal injection of ranibizumab at baseline and were retreated when there was evidence of disease recurrence (rescue). Patients were randomized 1:1 to receive topical LHA510 or vehicle for 12 weeks. Drops were administered twice a day for 8 weeks and then 3 times a day for the last 4 weeks. MAIN OUTCOME MEASURE: The primary outcome was the number of patients requiring rescue over 84 days of topical dosing. Key secondary outcome measures were time to first rescue, total number of ranibizumab injections, changes in central subfield thickness, and changes of visual acuity from baseline to day 84. RESULTS: The extended per protocol set included 70 patients of whom 25 of 33 patients in the LHA510 group (75.8%) and 25 of 37 patients in the placebo group (67.6%) required rescue by day 84 (P = .8466). Secondary and subgroup analysis did not support evidence of efficacy. Twenty-one of 46 patients administered LHA510 developed a reversible corneal haze that resolved with cessation of treatment and did not recur in patients restarted at once daily frequency. CONCLUSION: In spite of extensive optimization for topical efficacy, LHA510 failed to demonstrate clinical efficacy.


Assuntos
Degeneração Macular , Degeneração Macular Exsudativa , Inibidores da Angiogênese , Humanos , Indóis , Injeções Intravítreas , Degeneração Macular/tratamento farmacológico , Recidiva Local de Neoplasia , Pirazóis , Pirimidinas , Ranibizumab/uso terapêutico , Receptores de Fatores de Crescimento do Endotélio Vascular/uso terapêutico , Resultado do Tratamento , Fator A de Crescimento do Endotélio Vascular , Degeneração Macular Exsudativa/induzido quimicamente , Degeneração Macular Exsudativa/diagnóstico , Degeneração Macular Exsudativa/tratamento farmacológico
6.
Mol Imaging ; 10(3): 177-86, 1-3, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21496448

RESUMO

Imaging the location and extent of cancer provides invaluable information before, during, and after surgery. The majority of "image-guided" methods that use, for example, positron emission tomography (PET) involve preoperative imaging and do not provide real-time information during surgery. It is now well established that the inherent optical emissions (Cerenkov radiation) from various ß-emitting radionuclides can be visualized by Cerenkov luminescence imaging (CLI). Here we report the full characterization of CLI using the positron-emitting radiotracer 89Zr-DFO-trastuzumab for target-specific, quantitative imaging of HER2/neu-positive tumors in vivo. We also provide the first demonstration of the feasibility of using CLI for true image-guided, intraoperative surgical resection of tumors. Analysis of optical CLIs provided accurate, quantitative information on radiotracer biodistribution and tissue uptake that correlated well with the concordant PET images. CLI, PET, and biodistribution studies revealed target-specific uptake of 89Zr-DFO-trastuzumab in BT-474 (HER2/neu positive) versus MDA-MB-468 (HER2/neu negative) xenografts in the same mice. Competitive inhibition (blocking) studies followed by CLI also confirmed the in vivo immunoreactivity and specificity of 89Zr-DFO-trastuzumab for HER2/neu. Overall, these results strongly support the continued development of CLI as a preclinical and possible clinical tool for use in molecular imaging and surgical procedures for accurately defining tumor margins.


Assuntos
Cuidados Intraoperatórios/métodos , Luminescência , Tomografia por Emissão de Pósitrons/métodos , Radioisótopos , Animais , Anticorpos Monoclonais/farmacologia , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais Humanizados , Linhagem Celular Tumoral , Humanos , Camundongos , Neoplasias/diagnóstico por imagem , Neoplasias/tratamento farmacológico , Neoplasias/cirurgia , Fatores de Tempo , Distribuição Tecidual/efeitos dos fármacos , Trastuzumab
7.
Adv Exp Med Biol ; 676: 27-55, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20687468

RESUMO

Cytokinesis is the final step in cell division. The process begins during chromosome segregation, when the ingressing cleavage furrow begins to partition the cytoplasm between the nascent daughter cells. The process is not completed until much later, however, when the final cytoplasmic bridge connecting the two daughter cells is severed. Cytokinesis is a highly ordered process, requiring an intricate interplay between cytoskeletal, chromosomal and cell cycle regulatory pathways. A surprisingly broad range of additional cellular processes are also important for cytokinesis, including protein and membrane trafficking, lipid metabolism, protein synthesis and signaling pathways. As a highly regulated, complex process, it is not surprising that cytokinesis can sometimes fail. Cytokinesis failure leads to both centrosome amplification and production of tetraploid cells, which may set the stage for the development of tumor cells. However, tetraploid cells are abundant components of some normal tissues including liver and heart, indicating that cytokinesis is physiologically regulated. In this chapter, we summarize our current understanding of the mechanisms of cytokinesis, emphasizing steps in the pathway that may be regulated or prone to failure. Our discussion emphasizes findings in vertebrate cells although we have attempted to highlight important contributions from other model systems.


Assuntos
Cromossomos Humanos/metabolismo , Citocinese , Neoplasias/metabolismo , Poliploidia , Biossíntese de Proteínas , Transdução de Sinais , Animais , Transporte Biológico , Citoesqueleto/metabolismo , Humanos , Metabolismo dos Lipídeos , Proteínas de Neoplasias/biossíntese , Neoplasias/patologia
8.
Mol Biol Cell ; 18(12): 4847-58, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17881737

RESUMO

The mitotic cyclins promote cell division by binding and activating cyclin-dependent kinases (CDKs). Each cyclin has a unique pattern of subcellular localization that plays a vital role in regulating cell division. During mitosis, cyclin B1 is known to localize to centrosomes, microtubules, and chromatin. To determine the mechanisms of cyclin B1 localization in M phase, we imaged full-length and mutant versions of human cyclin B1-enhanced green fluorescent protein in live cells by using spinning disk confocal microscopy. In addition to centrosome, microtubule, and chromatin localization, we found that cyclin B1 also localizes to unattached kinetochores after nuclear envelope breakdown. Kinetochore recruitment of cyclin B1 required the kinetochore proteins Hec1 and Mad2, and it was stimulated by microtubule destabilization. Mutagenesis studies revealed that cyclin B1 is recruited to kinetochores through both CDK1-dependent and -independent mechanisms. In contrast, localization of cyclin B1 to chromatin and centrosomes is independent of CDK1 binding. The N-terminal domain of cyclin B1 is necessary and sufficient for chromatin association, whereas centrosome recruitment relies on sequences within the cyclin box. Our data support a role for cyclin B1 function at unattached kinetochores, and they demonstrate that separable and distinct sequence elements target cyclin B1 to kinetochores, chromatin, and centrosomes during mitosis.


Assuntos
Centrossomo/metabolismo , Cromatina/metabolismo , Ciclina B/metabolismo , Cinetocoros/metabolismo , Mitose , Animais , Sequência de Bases , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular , Cromatina/genética , Ciclina B/genética , Ciclina B1 , Proteínas do Citoesqueleto , Haplorrinos , Humanos , Proteínas Mad2 , Microtúbulos/metabolismo , Proteínas Nucleares/metabolismo , Ligação Proteica , Proteínas Repressoras/metabolismo
9.
Commun Biol ; 3(1): 16, 2020 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-31925329

RESUMO

Intravitreal (IVT) injection has become the standard route for drug administration in retinal diseases. However, the ability to measure biodistribution of ocular therapeutics in large species remains limited, due to the invasive nature of some techniques or their lack of spatial information. The aim of this study was to develop in cynomolgus monkeys a non-invasive fluorescence imaging technology that enables tracking of IVT-dosed drugs and could be easily translated into humans. Here, we show a proof-of-concept for labeled ranibizumab with observed half-lives of 3.34 and 4.52 days at the retina and in the vitreous, respectively. We further investigate a long acting anti-VEGF antibody, which remains as an agglomerate with some material leaking out until the end of the study at Day 35. Overall, we were able to visualize and measure differences in the in vivo behavior between short and long-acting antibodies, demonstrating the power of the technology for ocular pharmacokinetics.


Assuntos
Olho/efeitos dos fármacos , Imagem Molecular , Farmacocinética , Animais , Imagem Molecular/métodos , Imagem Óptica , Primatas , Estudo de Prova de Conceito , Ranibizumab/administração & dosagem , Ranibizumab/farmacocinética , Distribuição Tecidual , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores
10.
Urol Int ; 83(2): 160-5, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19752610

RESUMO

INTRODUCTION: The percentage of positive prostate biopsy cores (%PBC) has been shown to be a prognostic factor in localized prostate cancer. We hypothesized that it would predict time to hormonal independence and survival in prostate cancer patients treated with androgen deprivation therapy (ADT). PATIENTS AND METHODS: We used clinical data from 403 men treated with ADT between 1980 and 1999 and focused on a subgroup of 220 patients treated with GnRH analogue. %PBC was defined as the number of positive biopsy cores multiplied by 100 and divided by the total number of biopsy cores. RESULTS: Median %PBC was 83.3% (16.7-100%). Mean follow-up was 57.4 months. Survival at 5 years in men with 83.3% PBC or less was 62.3, 89.1 and 82.6% for recurrence-free, specific and overall survival, respectively, significantly better than that of men with a %PBC of more than 83.3% (32.2, 74.7 and 67.7%, respectively; p < 0.004). Among the factors available in the pretreatment setting, namely age, clinical stage, PSA, Gleason score, bone scan and %PBC, the latter was independently associated with survival in multivariate analysis. CONCLUSIONS: %PBC may improve the ability to predict time to hormonal resistance and survival in patients treated with ADT for prostate cancer. This finding warrants further investigation.


Assuntos
Antagonistas de Androgênios/uso terapêutico , Estrogênios/uso terapêutico , Hormônio Liberador de Gonadotropina/análogos & derivados , Orquiectomia , Neoplasias da Próstata/patologia , Neoplasias da Próstata/terapia , Idoso , Biópsia/estatística & dados numéricos , Humanos , Masculino , Prognóstico , Neoplasias da Próstata/mortalidade , Taxa de Sobrevida
11.
ACS Macro Lett ; 6(3): 235-240, 2017 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-29104818

RESUMO

In this study, we have synthesized a new hyperbranched polyester polymer containing sulfur-pendants (HBPE-S) in the branching points. This HBPE-S polymer is composed of spherical shaped, aliphatic three-dimensional architecture with carboxylic acid groups on the surface. The presence of sulfur pendants in the polymeric cavities demonstrated important role in the effective encapsulation of Bi-DOTA complexes ([Bi] = 5.21 µM), when compared to the previously reported polymer without sulfur pendants (HBPE, [Bi] = 1.07 x 10-3 µM). Higher X-ray blocking capability and excellent X-ray contrast images were obtained from Bi-DOTA encapsulating HBPE-S polymeric nanoparticles when compared with that of HBPE nanoparticles. In addition, the HBPE-S polymer's spherical structure with amphiphilic cavities allow for the successful encapsulation of anti-tumor drugs and optical dyes, indicating suitable for delivery of wide-range of theranostic agents for cancer diagnosis and treatment. Therapeutic drug taxol encapsulating, folic acid decorated HBPE-S-Fol nanoparticles showed more than 80% of lung carcinoma cell death within 24 h of incubation. Cell viability and microscopic experiments also confirmed for the targeted delivery, thereby minimizing toxicity to healthy tissues. Taken together, new HBPE-S polymer and multimodal theranostic nanoplatforms were synthesized with enhanced X-ray blocking capability for the effective cancer targeting and treatment monitoring.

12.
Oncogene ; 24(25): 4114-28, 2005 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-15750619

RESUMO

The human INK4a locus encodes two structurally unrelated tumor suppressor proteins, p16 INK4a and p14 ARF (p19 ARF in the mouse), which are frequently inactivated in human cancer. Both the proapoptotic and cell cycle-regulatory functions of p14 ARF were initially proposed to be strictly dependent on a functional p53/mdm-2 tumor suppressor pathway. However, a number of recent reports have implicated p53-independent mechanisms in the regulation of cell cycle arrest and apoptosis induction by p14 ARF. Here, we show that the G1 cell cycle arrest induced by p14 ARF entirely depends on both p53 and p21 in human HCT116 and DU145 carcinoma cells. In contrast, neither loss of p53 nor p21 impaired apoptosis induction by p14 ARF as evidenced by nuclear DNA fragmentation, phosphatidyl serine exposure, and caspase activation, which included caspase-3/7- and caspase-9-like activities. However, lack of functional p21 resulted in the accumulation of cells in G2/M phase of the cell cycle and markedly enhanced p14 ARF-induced apoptosis that was, nevertheless, efficiently inhibited by the cell permeable broad-spectrum caspase inhibitor zVAD-fmk (valyl-alanyl-aspartyl-(O)-methyl)-fluoromethylketone). Thus, loss of cell cycle restriction point control in the absence of p21 may interfere with p14 ARF-induced apoptosis. Finally, these data indicate that the signaling events required for G1 cell cycle arrest and apoptosis induction by p14 ARF dissociate upstream of p53.


Assuntos
Apoptose/fisiologia , Proteínas de Ciclo Celular/genética , Fase G1/fisiologia , Proteína Supressora de Tumor p14ARF/fisiologia , Adenoviridae/genética , Bromodesoxiuridina , Carcinoma , Caspases/metabolismo , Ciclo Celular/fisiologia , Linhagem Celular , Linhagem Celular Tumoral , Neoplasias Colorretais , Inibidor de Quinase Dependente de Ciclina p21 , Deleção de Genes , Vetores Genéticos , Humanos , Rim
13.
Prog Urol ; 16(4): 461-3, 2006 Sep.
Artigo em Francês | MEDLINE | ID: mdl-17069040

RESUMO

UNLABELLED: Although macroscopic haematuria during the month following transurethral resection of the prostate, due to sloughing of necrotic tissue, is a phenomenon well known to urologists since introduction of endoscopic resection, its pathophysiological and epidemiological characteristics are poorly defined. The objective of this retrospective study was to define the incidence of serious macroscopic haematuria after transurethral resection of the prostate (TURP) and to identify the risk factors for macroscopic haematuria. PATIENTS AND METHODS: The hospital database was used to identify patients treated by TURP between 1997 and 2004 and rehospitalized during the 31 days following the procedure. Files of patients presenting with haematuria and bladder clots were selected and analysed. RESULTS: Ten of a series of 624 patients undergoing TURP were hospitalised for bladder clots and their case files were analysed: median age: 72 years, median duration of TURP: 45 min and median weight of resection: 12 g. The operators' experience and the duration of post-TURP catheterization were not informative. In 2 cases, prostate cancer was diagnosed after analysis of resection chips. Two patients were treated by anticoagulants. Patients were essentially rehospitalized during the 2nd week (median: 11th day). A bladder catheter for was inserted for lavage in each case. No patient required reoperation or removal of clots under general anaesthesia. Two patients were transfused. CONCLUSION: We did not identify any risk factor for sloughing leading to macroscopic haematuria during the month following TURP. Macroscopic haematuria justifying rehospitalization is a rare event. However, in view of this low incidence, optimal analysis could only be performed in the context of a national prospective register.


Assuntos
Hematúria/epidemiologia , Hematúria/etiologia , Ressecção Transuretral da Próstata/efeitos adversos , Idoso , Humanos , Masculino , Estudos Retrospectivos
14.
Oncogene ; 23(26): 4523-35, 2004 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-15064710

RESUMO

The mitochondrial apoptosis pathway mediates cell death through the release of various pro-apoptotic factors including cytochrome c and Smac, the second mitochondrial activator of caspases, into the cytosol. Smac was shown previously to inhibit IAP proteins and to facilitate initiation of the caspase cascade upon cytochrome c release. To investigate Smac function during apoptosis and to explore Smac as an experimental cancer therapeutic, we constructed an expression system based on a single adenoviral vector containing Smac under control of the Tet-off system supplied in cis. Conditional expression of Smac induced apoptosis in human HCT116 and DU145 carcinoma cells regardless of the loss of Bax or overexpression of Bcl-x(L). Nevertheless, apoptosis induced by Smac was associated with cytochrome c release and breakdown of the mitochondrial membrane potential. This indicates that Smac acts independently of Bax and Bcl-x(L) during initiation of apoptosis and triggers a positive feedback loop that results in Bax/Bcl-x(L)-independent activation of mitochondria. In caspase-proficient cells, Smac-induced apoptosis could be inhibited partially by cell-permeable LEHD (caspase-9 inhibitor) and DEVD (caspase-3 inhibitor) peptides. Furthermore, loss of caspase-3 expression in MCF-7 cells carrying a caspase-3 null mutation completely abrogated the sensitivity for Smac-induced apoptotic or nonapoptotic, necrosis-like cell death, while re-expression of caspase-3 conferred sensitivity. Altogether, caspase-3 but not caspase-9 activation was necessary for execution of Smac-induced cell death. Notably, Smac did not induce caspase-9 processing in the absence of caspase-3. Thus, caspase-9 processing occurs secondary to caspase-3 activation during Smac-induced apoptosis. Altogether, Smac is capable of circumventing defects in mitochondrial apoptosis signaling such as loss of Bax or overexpression of Bcl-x(L) that are frequently observed in tumor cells resistant to anticancer therapy. Consequently, Smac appears to be a promising therapeutic target in anticancer treatment.


Assuntos
Carcinoma/metabolismo , Proteínas de Transporte/metabolismo , Caspases/metabolismo , Citocromos c/metabolismo , Proteínas Mitocondriais/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Adenoviridae/genética , Apoptose/fisiologia , Proteínas Reguladoras de Apoptose , Neoplasias da Mama/metabolismo , Carcinoma/tratamento farmacológico , Carcinoma/patologia , Proteínas de Transporte/genética , Caspase 3 , Caspase 9 , Inibidores de Caspase , Caspases/genética , Inibidores de Cisteína Proteinase/farmacologia , Ativação Enzimática , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Proteínas Mitocondriais/genética , Mutação , Oligopeptídeos/farmacologia , Processamento de Proteína Pós-Traducional , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-bcl-2/genética , Células Tumorais Cultivadas , Proteína X Associada a bcl-2 , Proteína bcl-X
15.
FASEB J ; 17(11): 1441-50, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12890698

RESUMO

The HIP/PAP (=human Reg-2) C-type lectin encoding gene is activated in primary liver cancers. In normal liver, the protein is undetectable in normal mature hepatocytes and found only in some ductular cells, representing potential hepatic progenitor cells. The aim of this study was to examine the consequences of human HIP/PAP expression in the liver of transgenic mice. We demonstrated that HIP/PAP stimulated liver regeneration after partial hepatectomy. To further investigate the enhanced liver regeneration observed in vivo, primary cultures of hepatocytes were used to evaluate the mitogenic and anti-apoptotic properties of HIP/PAP. HIP/PAP increased hepatocyte DNA synthesis and protected hepatocytes against TNF-alpha plus actinomycin-D-induced apoptosis. HIP/PAP anti-apoptotic effects against TNF-alpha were clearly demonstrated when protein kinase A activity was specifically inhibited by KT5720, and HIP/PAP stimulated PKA-dependent phosphorylation of the proapoptotic Bad protein at Ser-112, suggesting that HIP/PAP may compete with cAMP to stimulate PKA activity. Overall, our results led us to propose a new role for a C-type lectin, HIP/PAP, as a hepatic cytokine that combines mitogenic and anti-apoptotic functions regarding hepatocytes, and consequently acts as a growth factor in vivo to enhance liver regeneration.


Assuntos
Antígenos de Neoplasias/fisiologia , Apoptose , Biomarcadores Tumorais/fisiologia , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Lectinas Tipo C/fisiologia , Regeneração Hepática , Proteínas , Transdução de Sinais , Animais , Antígenos de Neoplasias/genética , Biomarcadores Tumorais/genética , Proteínas de Transporte/química , Proteínas de Transporte/metabolismo , Células Cultivadas , AMP Cíclico/metabolismo , DNA/biossíntese , Dactinomicina/toxicidade , Hepatectomia , Hepatócitos/metabolismo , Humanos , Lectinas Tipo C/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mitógenos/fisiologia , Proteínas Associadas a Pancreatite , Fosforilação , Serina/metabolismo , Fator de Necrose Tumoral alfa/toxicidade , Proteína de Morte Celular Associada a bcl
17.
ACS Nano ; 6(8): 7281-94, 2012 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-22809405

RESUMO

Herein we report a novel gadolinium-encapsulating iron oxide nanoparticle-based activatable NMR/MRI nanoprobe. In our design, Gd-DTPA is encapsulated within the poly(acrylic acid) (PAA) polymer coating of a superparamagnetic iron oxide nanoparticle (IO-PAA), yielding a composite magnetic nanoprobe (IO-PAA-Gd-DTPA) with quenched longitudinal spin-lattice magnetic relaxation (T(1)). Upon release of the Gd-DTPA complex from the nanoprobe's polymeric coating in acidic media, an increase in the T(1) relaxation rate (1/T(1)) of the composite magnetic nanoprobe was observed, indicating a dequenching of the nanoprobe with a corresponding increase in the T(1)-weighted MRI signal. When a folate-conjugated nanoprobe was incubated in HeLa cells, a cancer cell line overexpressing folate receptors, an increase in the 1/T(1) signal was observed. This result suggests that, upon receptor-mediated internalization, the composite magnetic nanoprobe degraded within the cell's lysosome acidic (pH 5.0) environment, resulting in an intracellular release of Gd-DTPA complex with subsequent T(1) activation. In addition, when an anticancer drug (Taxol) was coencapsulated with the Gd-DTPA within the folate receptor targeting composite magnetic nanoprobe, the T(1) activation of the probe coincided with the rate of drug release and corresponding cytotoxic effect in cell culture studies. Taken together, these results suggest that our activatable T(1) nanoagent could be of great importance for the detection of acidic tumors and assessment of drug targeting and release by MRI.


Assuntos
Gadolínio , Imageamento por Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética/métodos , Nanopartículas de Magnetita , Miócitos Cardíacos/citologia , Nanocápsulas , Linhagem Celular , Meios de Contraste/síntese química , Gadolínio/química , Células HeLa , Humanos , Nanopartículas de Magnetita/química , Nanocápsulas/química
18.
Nat Cell Biol ; 13(3): 324-30, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21336303

RESUMO

Aneuploidy is common in human tumours and is often indicative of aggressive disease. Aneuploidy can result from cytokinesis failure, which produces binucleate cells that generate aneuploid offspring with subsequent divisions. In cancers, disruption of cytokinesis is known to result from genetic perturbations to mitotic pathways or checkpoints. Here we describe a non-genetic mechanism of cytokinesis failure that occurs as a direct result of cell-in-cell formation by entosis. Live cells internalized by entosis, which can persist through the cell cycle of host cells, disrupt formation of the contractile ring during host cell division. As a result, cytokinesis frequently fails, generating binucleate cells that produce aneuploid cell lineages. In human breast tumours, multinucleation is associated with cell-in-cell structures. These data define a previously unknown mechanism of cytokinesis failure and aneuploid cell formation that operates in human cancers.


Assuntos
Aneuploidia , Regulação Neoplásica da Expressão Gênica , Mitose , Neoplasias/patologia , Linhagem Celular , Linhagem Celular Tumoral , Linhagem da Célula , Citocinese , Entose , Proteínas de Fluorescência Verde/metabolismo , Humanos , Hibridização in Situ Fluorescente , Microscopia de Fluorescência/métodos , Modelos Biológicos , Modelos Genéticos , Neoplasias/metabolismo
19.
Cell ; 131(5): 966-79, 2007 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-18045538

RESUMO

Epithelial cells require attachment to extracellular matrix (ECM) to suppress an apoptotic cell death program termed anoikis. Here we describe a nonapoptotic cell death program in matrix-detached cells that is initiated by a previously unrecognized and unusual process involving the invasion of one cell into another, leading to a transient state in which a live cell is contained within a neighboring host cell. Live internalized cells are either degraded by lysosomal enzymes or released. We term this cell internalization process entosis and present evidence for entosis as a mechanism underlying the commonly observed "cell-in-cell" cytological feature in human cancers. Further we propose that entosis is driven by compaction force associated with adherens junction formation in the absence of integrin engagement and may represent an intrinsic tumor suppression mechanism for cells that are detached from ECM.


Assuntos
Apoptose/fisiologia , Autofagia/fisiologia , Comunicação Celular/fisiologia , Actinas/fisiologia , Junções Aderentes/fisiologia , Neoplasias da Mama/patologia , Caderinas/fisiologia , Carcinoma/patologia , Adesão Celular/fisiologia , Matriz Extracelular/metabolismo , Humanos , Lisossomos/metabolismo , Modelos Biológicos , Miosina Tipo II/fisiologia , Células Tumorais Cultivadas , Proteínas rho de Ligação ao GTP/fisiologia , Quinases Associadas a rho/fisiologia
20.
J Biol Chem ; 280(8): 7118-30, 2005 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-15582998

RESUMO

The human INK4a gene locus encodes two structurally unrelated tumor suppressor proteins, p16(INK4a) and p14(ARF). Although primarily proposed to require a functional p53.Mdm-2 signaling axis, recently p14(ARF) has been implicated in p53-independent cell cycle regulation. Here we show that p14(ARF) preferentially induces a G(2) arrest in tumor cells lacking functional p53 and/or p21. Expression of p14(ARF) impaired mitotic entry and enforced a primarily cytoplasmic localization of p34(cdc2) that was associated with a decrease in p34(cdc2) kinase activity and reduced p34(cdc2) protein expression. A direct physical interaction between p14(ARF) and p34(cdc2) was, nevertheless, ruled out by lack of co-immunoprecipitation. The p14(ARF)-induced depletion of p34(cdc2) was associated with impaired cdc25C phosphatase expression and a prominent shift to inhibitory Tyr-15-phosphorylation in G(2)-arrested cells lacking either p53, p21, or both. Finally, reconstitution of p34(cdc2) using a constitutively active, phosphorylation-deficient p34(cdc2AF) mutant alleviated this p14(ARF)-induced G(2) arrest, thereby allowing cell cycle progression. Taken together, these data indicate that p14(ARF) arrests cells lacking functional p53/p21 in the G(2) phase of the cell cycle by targeting p34(cdc2) kinase. This may represent an important fail-safe mechanism by which p14(ARF) protects p53/p21-deficient cells from unrestrained proliferation.


Assuntos
Proteína Quinase CDC2/metabolismo , Proteínas de Ciclo Celular/genética , Regulação para Baixo , Fase G2 , Proteína Supressora de Tumor p14ARF/fisiologia , Proteína Supressora de Tumor p53/genética , Ciclo Celular , Linhagem Celular Tumoral , Proliferação de Células , Inibidor de Quinase Dependente de Ciclina p21 , Regulação Neoplásica da Expressão Gênica , Humanos , Fosforilação , Proteína Supressora de Tumor p53/deficiência , Fosfatases cdc25/deficiência
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