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1.
Scand J Immunol ; 77(3): 171-6, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23298316

RESUMO

Most mammal-derived respiratory allergens belong to the lipocalin family of proteins. Determinants of their allergenic capacity are still unknown. Innate immune cells, in particular dendritic cells, have been shown to be involved in the allergenicity of some proteins. As recognition by dendritic cells is one of the few plausible mechanisms for the allergenicity of proteins, we wanted to investigate their role in the allergenicity of lipocalin allergens. Therefore, we first incubated human monocyte-derived dendritic cells with immunologically functional recombinant allergens mouse Mus m 1, dog Can f 1 and 2, cow Bos d 2, horse Equ c 1 and natural Bos d 2. Then, the surface marker expression and cytokine production of dendritic cells and their capacity to promote T cell proliferation and Th2 immune deviation in naïve CD4(+) T cells were examined in vitro. We found that near to endotoxin-free lipocalin allergens had no effect on the activation, allostimulatory capacity or cytokine production of dendritic cells. The dendritic cells could not induce immune deviation in naïve CD4(+) T cells. In contrast, lipopolysaccharide activated the dendritic cells efficiently. However, lipocalin allergens were not able to modify the lipopolysaccharide-induced responses. We conclude that an important group of mammal-derived respiratory allergens, lipocalins, appear not to be able to activate dendritic cells, a major component involved in the allergenicity of some proteins. It is conceivable that this incapacity of lipocalin allergens to arouse innate immunity may be associated with their poor capacity to induce a strong T cell response, verified in several studies.


Assuntos
Alérgenos/imunologia , Células Dendríticas/imunologia , Lipocalinas/imunologia , Alérgenos/farmacologia , Animais , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Bovinos , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/imunologia , Proliferação de Células , Células Cultivadas , Técnicas de Cocultura , Citocinas/metabolismo , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/metabolismo , Cães , Citometria de Fluxo , Glicoproteínas/imunologia , Cavalos , Humanos , Lipocalinas/farmacologia , Lipopolissacarídeos/imunologia , Lipopolissacarídeos/farmacologia , Ativação Linfocitária/efeitos dos fármacos , Ativação Linfocitária/imunologia , Camundongos , Linfócitos T Auxiliares-Indutores/efeitos dos fármacos , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/metabolismo
2.
J Cancer Res Clin Oncol ; 136(9): 1377-87, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20151151

RESUMO

PURPOSE: The study focuses on p120catenin, a regulator of cell adhesion, which has previously been described in many malignancies and suggested with a role in invasion and metastatic behaviour. In this study, we investigate the role of altered immunoexpression of p120catenin isoforms in the prognosis of invasive breast cancer (n = 351). METHODS: We used cDNA microarrays to screen differences in gene expression in invasive breast cancer in general, and between local and metastasized disease particularly. On this basis, we performed p120catenin immunohistochemistry in order to confirm the prognostic value of p120catenin isoforms on tissue microarrays comprising 341 patients from the era of mammographic screening, directed to modern surgical and oncological treatments, and followed-up for maximum of 20 years. RESULTS: In cDNA microarray analysis, p120catenin was discovered down-regulated along with E-cadherin and alpha-catenin. In addition, p120catenin distinguished metastasized breast cancer from local disease. Immunohistochemistry confirmed the value of p120catenin as an independent prognosticator of breast cancer survival. In our results, p120catenin was associated with 3.7-fold risk of breast cancer death in multivariate Cox's regression analyses adjusted for the established prognosticators of breast cancer (p = 0.039). Particularly, the long isoform of p120catenin predicted metastatic disease (p = 0.029). CONCLUSION: The present paper is the first report on p120catenin in invasive breast cancer based on a well-characterized patient material with long-term follow-up. We observed altered expression of p120catenin isoforms in invasive breast cancer and, in our material, the decrease in p120 immunoexpression was significantly associated with poor outcome of disease.


Assuntos
Neoplasias da Mama/diagnóstico , Neoplasias da Mama/metabolismo , Cateninas/metabolismo , Regulação Neoplásica da Expressão Gênica , Idoso , Neoplasias da Mama/genética , Cateninas/biossíntese , Cateninas/genética , Progressão da Doença , Feminino , Seguimentos , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , Invasividade Neoplásica/genética , Invasividade Neoplásica/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Valor Preditivo dos Testes , Prognóstico , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Análise de Sobrevida , delta Catenina
3.
Phys Rev Lett ; 105(20): 202501, 2010 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-21231223

RESUMO

The ß feeding probability of (102,104,105,106,107)Tc, 105Mo, and 101Nb nuclei, which are important contributors to the decay heat in nuclear reactors, has been measured using the total absorption technique. We have coupled for the first time a total absorption spectrometer to a Penning trap in order to obtain sources of very high isobaric purity. Our results solve a significant part of a long-standing discrepancy in the γ component of the decay heat for 239Pu in the 4-3000 s range.

4.
Dig Surg ; 26(5): 378-83, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19923825

RESUMO

BACKGROUND: Early gastric cancer (EGC) is associated with better prognosis than advanced cancer of the stomach. Unfortunately, EGC accounts for a minority of operated gastric cancers in Europe. The aim of this study was to evaluate the clinical characteristics of EGC and the outcome after surgery. METHODS: The study group comprised 94 EGC patients having undergone surgery at Helsinki University Central Hospital between April 1983 and July 2007. RESULTS: The overall 5-year survival rate of EGC patients was 92.4%. Tumor location in the upper part of the stomach and mixed histological type impaired the prognosis (p = 0.043 and 0.008, respectively). The probability of lymph node metastasis was significantly higher when the tumor infiltrated gastric submucosa rather than mucosa (p = 0.012). Existence of lymph node or distant metastases decreased the survival rates (both p < 0.001). Total gastrectomy, pancreatic resection, and extended D2 lymph node dissection increased the complication rate, but did not have effect on survival. CONCLUSION: The overall prognosis of EGC is favorable. The survival rates of EGC decreased when the tumor was located in the upper part of the stomach or was of mixed histological type, or the patient had lymph node or distant metastasis.


Assuntos
Adenocarcinoma/cirurgia , Gastrectomia , Neoplasias Gástricas/cirurgia , Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Finlândia/epidemiologia , Gastrectomia/efeitos adversos , Gastrectomia/métodos , Gastrectomia/mortalidade , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Neoplasias Gástricas/mortalidade , Neoplasias Gástricas/patologia , Análise de Sobrevida , Taxa de Sobrevida , Fatores de Tempo , Resultado do Tratamento
5.
Br J Cancer ; 101(6): 1005-10, 2009 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-19690544

RESUMO

BACKGROUND: Securin is a recently recognised oncogene with multiple known functions in initiation, progression and cell cycle regulation in several malignant diseases, including breast carcinoma. METHODS: In this paper, the prognostic value of securin is evaluated by immunohistochemistry in 310 patients diagnosed with invasive breast cancer during a mammographic screening programme in Central Finland. All patients were directed to modern surgical and oncological treatments and were followed up for a maximum of 20 years. RESULTS: Our results suggest that securin immunopositivity is an independent prognosticator of invasive breast cancer. In our study, securin predicted breast cancer-specific survival among all cases of invasive breast cancer and subgroups divided according to histological type, Ki-67 proliferation status and tumour size. Especially in a multivariate analysis standardised for axillary lymph node status, patient's age and tumour size at the time of diagnosis, securin immunopositivity indicated a 13.1-fold risk of breast cancer death (P=0.024) among invasive ductal breast carcinomas with low Ki-67 positivity. CONCLUSION: Our present and previous results suggest that securin could be useful in clinical pathology to intensify the power of the established prognosticators of invasive breast cancer and, especially, to assist in identifying patients with a more favourable outcome than that indicated by Ki-67 alone.


Assuntos
Neoplasias da Mama/mortalidade , Proteínas de Neoplasias/análise , Idoso , Neoplasias da Mama/química , Neoplasias da Mama/patologia , Proliferação de Células , Feminino , Humanos , Imuno-Histoquímica , Antígeno Ki-67/análise , Pessoa de Meia-Idade , Prognóstico , Securina
6.
Scand J Immunol ; 65(2): 176-81, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17257223

RESUMO

Severe forms of chronic periodontitis affect up to 10% of adults. Tumour necrosis factor and lymphotoxin-alpha genes in the major histocompatibility complex are associated with severe periodontitis. Complement factor C4 is a nearby, polymorphic, functionally relevant gene region. Although associated with chronic mucosal infections, C4 deficiencies have not been assessed in adult periodontitis patients. We tested whether complement levels are systemically altered and C4 deficiencies associated with severe chronic periodontitis. In a case-control study, we analysed levels of plasma C3, and C4, serum classical pathway haemolytic activity, C4 allotypes and C4 gene numbers in 37 patients with severe chronic periodontitis and in 150 voluntary controls. Plasma levels of C3 were higher, and classical pathway haemolytic activity was lower in patients than in controls. Partial C4 gene deficiencies were more frequent in patients than in controls (odds ratio 2.4, 95% confidence interval 1.1-5.5, P = 0.032). Changes in complement levels may reflect chronic, recurring inflammation. C4 gene deficiencies are associated with predisposition to chronic periodontitis.


Assuntos
Complemento C4/genética , Predisposição Genética para Doença , Periodontite/genética , Periodontite/imunologia , Adulto , Alelos , Estudos de Casos e Controles , Doença Crônica , Complemento C1/análise , Complemento C4/análise , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
7.
Phys Rev Lett ; 96(4): 042504, 2006 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-16486814

RESUMO

Atomic masses of 95-100Sr, 98-105Zr, and [corrected] 102-110Mo and have been measured with a precision of 10 keV employing a Penning trap setup at the IGISOL facility. Masses of 104,105Zr and 109,110Mo are measured for the first time. Our improved results indicate significant deviations from the previously published values deduced from beta end point measurements. The most neutron-rich studied isotopes are found to be significantly less bound (1 MeV) compared to the 2003 atomic mass evaluation. A strong correlation between nuclear deformation and the binding energy is observed in the two-neutron separation energy in all studied isotope chains.

8.
Ann Rheum Dis ; 63(10): 1327-30, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15361394

RESUMO

OBJECTIVES: To determine whether inflammation in the gut associated immune system is activated in rheumatoid arthritis (RA). The expression of chemokine receptor- (CCR4, CCR5) and cytokine- (interleukin (IL)2, IL10, interferon gamma (IFNgamma), tumour necrosis factor alpha (TNFalpha), and transforming growth factor beta (TGFbeta)) specific mRNA in intestinal biopsy samples from patients with RA was examined. METHODS: Duodenal biopsy samples from 13 patients with RA and 15 control subjects were studied. The mRNA expression of CCR4, CCR5, IL2, IL10, IFNgamma, TNFalpha, and TGFbeta in intestinal biopsy samples was demonstrated by real time quantitative reverse transcriptase-polymerase chain reaction. RESULTS: The mRNA expression of CCR4, CCR5, and IL10 in intestinal biopsy samples was increased in patients with RA in comparison with control subjects (p = 0.001, p = 0.046, p = 0.019). No difference in the expression levels of IL2, IFNgamma, TNFalpha, or TGFbeta was seen between patients with RA and controls. CONCLUSIONS: The increased intestinal mRNA expression of IL10, CCR5, and CCR4 suggests that gut associated immune cells are activated in patients with RA.


Assuntos
Artrite Reumatoide/imunologia , Duodeno/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Artrite Reumatoide/patologia , Biópsia , Citocinas/biossíntese , Citocinas/genética , Duodeno/patologia , Feminino , Gastroscopia , Expressão Gênica , Humanos , Interleucina-10/biossíntese , Interleucina-10/genética , Masculino , Pessoa de Meia-Idade , RNA Mensageiro/genética , Receptores CCR4 , Receptores CCR5/biossíntese , Receptores CCR5/genética , Receptores de Quimiocinas/biossíntese , Receptores de Quimiocinas/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Estômago/patologia
9.
Phys Rev Lett ; 89(8): 082501, 2002 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-12190460

RESUMO

The first on-line laser spectroscopy of cooled fission fragments is reported. The r ions, produced in uranium fission, were extracted and separated using an ion guide isotope separator. The ions were cooled and bunched for collinear laser spectroscopy by a gas-filled linear Paul trap. New results for nuclear mean-square charge radii, dipole, and quadrupole moments are reported across the N=60 shape change. The mean-square charge radii are found to be almost identical to those of the Sr isotones and previously offered modeling of the radial changes is critically reviewed.

10.
Phys Rev Lett ; 89(8): 085902, 2002 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-12190483

RESUMO

Self-diffusion of implanted (31)Si and (71)Ge in relaxed Si(0.20)Ge(0.80) layers has been studied in the temperature range 730-950 degrees C by means of a modified radiotracer technique. The temperature dependences of the diffusion coefficients were found to be Arrhenius-type with activation enthalpies of 3.6 eV and 3.5 eV and preexponential factors of 7.5 x 10(-3) m(2) s(-1) and 8.1 x 10(-3) m(2) s(-1) for (31)Si and (71)Ge , respectively. These results suggest that, as in Ge, in Si(0.20)Ge(0.80) both (31)Si and (71)Ge diffuse via a vacancy mechanism. Since in Si(0.20)Ge(0.80) (71)Ge diffuses only slightly faster than (31)Si , in self-diffusion studies on Si-Ge (71)Ge radioisotopes may be used as substitutes for the "uncomfortably" short-lived (31)Si radiotracer atoms.

11.
Phys Rev Lett ; 88(9): 094801, 2002 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-11864015

RESUMO

A new method has been developed for increasing the sensitivity of collinear laser spectroscopy. The method utilizes an ion-trapping technique in which a continuous low-energy ion beam is cooled and accumulated in a linear Paul trap and subsequently released as a short (10-20 micros) bunch. In collinear laser measurements the signal-to-noise ratio has been improved by a factor of 2 x 10(4), allowing spectroscopic measurements to be made with ion-beam fluxes of approximately 50 ions s(-1). The bunching method has been demonstrated in an on-line isotope shift and hyperfine structure measurement on radioactive (175)Hf.

12.
J Biol Chem ; 276(50): 47379-86, 2001 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-11579101

RESUMO

Photodynamic therapy (PDT), a novel and promising cancer treatment that employs a combination of a photosensitizing chemical and visible light, induces apoptosis in human epidermoid carcinoma A431 cells. However, the precise mechanism of PDT-induced apoptosis is not well characterized. To dissect the pathways of PDT-induced apoptosis, we investigated the involvement of mitochondrial damage by examining a second generation photosensitizer, the silicon phthalocyanine 4 (Pc 4). By using laser-scanning confocal microscopy, we found that Pc 4 localized to cytosolic membranes primarily, but not exclusively, in mitochondria. Formation of mitochondrial reactive oxygen species (ROS) was detected within minutes when cells were exposed to Pc 4 and 670-675 nm light. This was followed by mitochondrial inner membrane permeabilization, depolarization and swelling, cytochrome c release, and apoptotic death. Desferrioxamine prevented mitochondrial ROS production and the events thereafter. Cyclosporin A plus trifluoperazine, blockers of the mitochondrial permeability transition, inhibited mitochondrial inner membrane permeabilization and depolarization without affecting mitochondrial ROS generation. These data indicate that the mitochondrial ROS are critical in initiating mitochondrial inner membrane permeabilization, which leads to mitochondrial swelling, cytochrome c release to the cytosol, and apoptotic death during PDT with Pc 4.


Assuntos
Apoptose , Carcinoma/metabolismo , Indóis/metabolismo , Membranas Intracelulares/metabolismo , Mitocôndrias/metabolismo , Fotoquimioterapia , Espécies Reativas de Oxigênio , Neoplasias Cutâneas/metabolismo , Western Blotting , Caspase 3 , Inibidores de Caspase , Membrana Celular/metabolismo , Sobrevivência Celular , Grupo dos Citocromos c/metabolismo , Citosol/metabolismo , Desferroxamina/farmacologia , Antagonistas de Dopamina/farmacologia , Relação Dose-Resposta à Radiação , Inibidores Enzimáticos/farmacologia , Humanos , Quelantes de Ferro/farmacologia , Luz , Microscopia Confocal , Modelos Biológicos , Fármacos Fotossensibilizantes/farmacologia , Fatores de Tempo , Trifluoperazina/farmacologia , Células Tumorais Cultivadas
13.
Mol Pharmacol ; 60(5): 1008-19, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11641429

RESUMO

We investigated cytochrome c release kinetics in response to three apoptosis-inducing agents (tumor necrosis factor-alpha, staurosporine, and valinomycin) in MCF-7/Casp-3 cells stably transfected with enhanced green fluorescent protein (EGFP)-tagged cytochrome c. All three agents induced significant caspase activation in the cultures determined by monitoring the cleavage of fluorigenic caspase substrates in extracts from drug-treated MCF-7/Casp-3 cells, albeit the valinomycin-induced activation was less pronounced. Time-lapse confocal microscopy showed that tumor necrosis factor-alpha and staurosporine caused rapid, one- or multiple-step release of cytochrome c-EGFP from mitochondria. In contrast, valinomycin-induced cytochrome c-EGFP release occurred slowly over several hours. Unlike staurosporine, the valinomycin-induced cytochrome c release was not associated with translocation of the proapoptotic Bax protein to the mitochondria, and was not accompanied by co-release of the proapoptotic Smac protein. Immunoprecipitation experiments revealed that cytochrome c was also released out of the cell into the extracellular space before loss of plasma membrane integrity. Our data indicate the existence of multiple kinetics of cytochrome c release in drug-induced apoptosis.


Assuntos
Apoptose , Cicloeximida/farmacologia , Grupo dos Citocromos c/metabolismo , Mitocôndrias/efeitos dos fármacos , Fator de Necrose Tumoral alfa/farmacologia , Inibidores de Caspase , Caspases/metabolismo , Digitonina/metabolismo , Interações Medicamentosas , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Proteínas de Fluorescência Verde , Humanos , Indicadores e Reagentes/metabolismo , Cinética , Proteínas Luminescentes/química , Mitocôndrias/enzimologia , Inibidores da Síntese de Proteínas/farmacologia , Estaurosporina/farmacologia , Células Tumorais Cultivadas , Valinomicina/farmacologia
14.
J Biol Chem ; 276(34): 32257-63, 2001 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-11413128

RESUMO

Apoptosis is a physiological counterbalance to mitosis and plays important roles in tissue development and homeostasis. Cytosolic Ca(2+) has been implicated as a proapoptotic second messenger involved in both triggering apoptosis and regulating cell death-specific enzymes. A critical early event in apoptosis is associated with the redistribution of Bax from cytosol to mitochondria and endoplasmic reticulum (ER) membranes; however, the molecular mechanism of Bax translocation and its relationship to Ca(2+) is largely unknown. Here we provide functional evidence for a synergistic interaction between the movements of intracellular Ca(2+) and cytosolic Bax in the induction of apoptosis. Overexpression of Bax in cultured cells causes a loss of ER Ca(2+) content. Depletion of ER Ca(2+) through activation of the ryanodine receptor enhances the participation of Bax into the mitochondrial membrane. Neither Bax translocation nor Bax-induced apoptosis is affected by buffering of cytosolic Ca(2+) with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, suggesting that depletion of ER Ca(2+) rather than elevation of cytosolic Ca(2+) is the signal for cell apoptosis. This dynamic interplay of Ca(2+) and Bax movements may serve as an amplifying factor in the initial signaling steps of apoptosis.


Assuntos
Apoptose , Cálcio/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Animais , Células CHO , Cricetinae , Ácido Egtázico/análogos & derivados , Retículo Endoplasmático/metabolismo , Homeostase , Imuno-Histoquímica , Indicadores e Reagentes , Microscopia Confocal , Transporte Proteico , Proteínas Proto-Oncogênicas c-bcl-2/genética , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , Transfecção , Proteína X Associada a bcl-2 , Proteína bcl-X
15.
J Neurosci ; 21(13): 4551-63, 2001 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-11426445

RESUMO

Exposure of rat hippocampal neurons or human D283 medulloblastoma cells to the apoptosis-inducing kinase inhibitor staurosporine induced rapid cytochrome c release from mitochondria and activation of the executioner caspase-3. Measurements of cellular tetramethylrhodamine ethyl ester fluorescence and subsequent simulation of fluorescence changes based on Nernst calculations of fluorescence in the extracellular, cytoplasmic, and mitochondrial compartments revealed that the release of cytochrome c was preceded by mitochondrial hyperpolarization. Overexpression of the anti-apoptotic protein Bcl-xL, but not pharmacological blockade of outward potassium currents, inhibited staurosporine-induced hyperpolarization and apoptosis. Dissipation of mitochondrial potassium and proton gradients by valinomycin or carbonyl cyanide p-trifluoromethoxy-phenylhydrazone also potently inhibited staurosporine-induced hyperpolarization, cytochrome c release, and caspase activation. This effect was not attributable to changes in cellular ATP levels. Prolonged exposure to valinomycin induced significant matrix swelling, and per se also caused release of cytochrome c from mitochondria. In contrast to staurosporine, however, valinomycin-induced cytochrome c release and cell death were not associated with caspase-3 activation and insensitive to Bcl-xL overexpression. Our data suggest two distinct mechanisms for mitochondrial cytochrome c release: (1) active cytochrome c release associated with early mitochondrial hyperpolarization, leading to neuronal apoptosis, and (2) passive cytochrome c release secondary to mitochondrial depolarization and matrix swelling.


Assuntos
Apoptose , Grupo dos Citocromos c/metabolismo , Mitocôndrias/metabolismo , Neurônios/metabolismo , Potássio/metabolismo , Animais , Caspase 3 , Caspases/metabolismo , Células Cultivadas , Inibidores Enzimáticos/farmacologia , Corantes Fluorescentes/farmacocinética , Hipocampo/citologia , Hipocampo/metabolismo , Imuno-Histoquímica , Ionóforos/farmacologia , Meduloblastoma/metabolismo , Neurônios/citologia , Proteínas Proto-Oncogênicas c-bcl-2/biossíntese , Proteínas Proto-Oncogênicas c-bcl-2/genética , Prótons , Ratos , Ratos Endogâmicos F344 , Estaurosporina/farmacologia , Transfecção , Valinomicina/farmacologia , Proteína bcl-X
16.
Cancer Lett ; 165(1): 51-8, 2001 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-11248418

RESUMO

Photodynamic therapy (PDT) activates the mitochondrial pathway of apoptosis, for which the release of cytochrome c into the cytosol is considered critical. To further elucidate the role of cytochrome c release in PDT-induced apoptosis, we monitored cytochrome c localization immunocytochemically and related it to nuclear apoptosis of the same cells. When mouse L5178Y-R cells were treated with 300 nM phthalocyanine (Pc) 4 and 0-75 mJ/cm(2) red light, cytochrome c release had a dose response similar to that of clonogenic cell killing, with nearly identical threshold doses. Within individual cells, the release of cytochrome c appeared to be an all-or-none phenomenon. Moreover, it was tightly associated with activation of a caspase-3-like protease and changes in nuclear morphology. Thus, in response to Pc 4-PDT, the release of cytochrome c from mitochondria is a key determinant of apoptotic cell death.


Assuntos
Apoptose , Grupo dos Citocromos c/metabolismo , Indóis/farmacologia , Leucemia L5178/patologia , Fármacos Fotossensibilizantes/farmacologia , Animais , Caspase 3 , Caspases/efeitos dos fármacos , Caspases/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ativação Enzimática , Imuno-Histoquímica , Camundongos , Fotoquimioterapia , Frações Subcelulares/efeitos dos fármacos , Fatores de Tempo , Células Tumorais Cultivadas , Ensaio Tumoral de Célula-Tronco
17.
FASEB J ; 15(3): 758-67, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11259394

RESUMO

The complete AIF cDNA comprising the amino-terminal mitochondrial localization sequence (MLS) and the oxidoreductase domain has been fused in its carboxyl terminus to enhanced green fluorescent protein (GFP), thereby engineering an AIF-GFP fusion protein that is selectively targeted to the mitochondrial intermembrane space. Upon induction of apoptosis, the AIF-GFP protein translocates together with cytochrome c (Cyt-c) to the extramitochondrial compartment. Microinjection of recombinant AIF leads to the release of AIF-GFP and Cyt-c-GFP, indicating that ectopic AIF can favor permeabilization of the outer mitochondrial membrane. These mitochondrial effects of AIF are caspase independent, whereas the Cyt-c-microinjection induced translocation of AIF-GFP and Cyt-c-GFP is suppressed by the pan-caspase inhibitor Z-VAD.fmk. Upon prolonged culture, transfection-enforced overexpression of AIF results in spontaneous translocation of AIF-GFP from mitochondria, nuclear chromatin condensation, and cell death. These effects are caspase independent and do not rely on the oxidoreductase function of AIF. Spontaneous AIF-GFP translocation and subsequent nuclear apoptosis can be retarded by overexpression of a Bcl-2 protein selectively targeted to mitochondria, but not by a Bcl-2 protein targeted to the endoplasmic reticulum. Overexpression of a mutant AIF protein in which the MLS has been deleted (AIF Delta 1-100) results in the primary cytosolic accumulation of AIF. AIF Delta 1-100-induced cell death is suppressed by neither Z-VAD.fmk or by Bcl-2. Thus, extramitochondrially targeted AIF is a dominant cell death inducer.


Assuntos
Apoptose/fisiologia , Flavoproteínas/metabolismo , Proteínas de Membrana/metabolismo , Mitocôndrias/metabolismo , Sinais Direcionadores de Proteínas/genética , Transporte Proteico/fisiologia , Transporte Ativo do Núcleo Celular , Sequência de Aminoácidos , Animais , Fator de Indução de Apoptose , Células COS , Clonagem Molecular , Cricetinae , Grupo dos Citocromos c/genética , Grupo dos Citocromos c/metabolismo , Flavoproteínas/genética , Corantes Fluorescentes/metabolismo , Genes Reporter/genética , Proteínas de Fluorescência Verde , Humanos , Proteínas Luminescentes/metabolismo , Proteínas de Membrana/genética , Microinjeções , Microscopia Confocal , Dados de Sequência Molecular , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ratos , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Alinhamento de Sequência , Fatores de Tempo , Transfecção
18.
J Biol Chem ; 276(22): 19150-9, 2001 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-11279125

RESUMO

beta-Lapachone (beta-Lap) triggers apoptosis in a number of human breast and prostate cancer cell lines through a unique apoptotic pathway that is dependent upon NQO1, a two-electron reductase. Downstream signaling pathway(s) that initiate apoptosis following treatment with beta-Lap have not been elucidated. Since calpain activation was suspected in beta-Lap-mediated apoptosis, we examined alterations in Ca(2+) homeostasis using NQO1-expressing MCF-7 cells. beta-Lap-exposed MCF-7 cells exhibited an early increase in intracellular cytosolic Ca(2+), from endoplasmic reticulum Ca(2+) stores, comparable to thapsigargin exposures. 1,2-Bis-(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester, an intracellular Ca(2+) chelator, blocked early increases in Ca(2+) levels and inhibited beta-Lap-mediated mitochondrial membrane depolarization, intracellular ATP depletion, specific and unique substrate proteolysis, and apoptosis. The extracellular Ca(2+) chelator, EGTA, inhibited later apoptotic end points (observed >8 h, e.g. substrate proteolysis and DNA fragmentation), suggesting that later execution events were triggered by Ca(2+) influxes from the extracellular milieu. Collectively, these data suggest a critical, but not sole, role for Ca(2+) in the NQO1-dependent cell death pathway initiated by beta-Lap. Use of beta-Lap to trigger an apparently novel, calpain-like-mediated apoptotic cell death could be useful for breast and prostate cancer therapy.


Assuntos
Cálcio/metabolismo , Morte Celular , Naftoquinonas/metabolismo , Transdução de Sinais , 4-Nitroquinolina-1-Óxido/farmacologia , Trifosfato de Adenosina/metabolismo , Apoptose , Western Blotting , Neoplasias da Mama/metabolismo , Divisão Celular , Quelantes/farmacologia , Citosol/metabolismo , Fragmentação do DNA , Relação Dose-Resposta a Droga , Ácido Egtázico/análogos & derivados , Ácido Egtázico/farmacologia , Retículo Endoplasmático/metabolismo , Feminino , Citometria de Fluxo , Humanos , Marcação In Situ das Extremidades Cortadas , Masculino , Potenciais da Membrana , Microscopia Confocal , Mitocôndrias/metabolismo , Modelos Biológicos , Naftoquinonas/farmacologia , Neoplasias da Próstata/metabolismo , Quinolonas/farmacologia , Fatores de Tempo , Células Tumorais Cultivadas
19.
Photochem Photobiol ; 71(5): 634-9, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10818795

RESUMO

Photodynamic therapy (PDT) is a novel cancer therapy that uses light-activated drugs (photosensitizers) to destroy tumor tissue. Reactive oxygen species produced during PDT are thought to cause the destruction of tumor tissue. However, the precise mechanism of PDT is not completely understood. To provide insight into the in vitro mechanisms of PDT, we studied the subcellular localization of the photosensitizer HOSiPcOSi(CH3)2-(CH2)3N(CH3)2 (Pc 4) in mouse lymphoma (LY-R) cells using double-label confocal fluorescence microscopy. This technique allowed us to observe the relative distributions of Pc 4 and an organelle-specific dye within the same cell via two, spectrally distinct, fluorescence images. To quantify the localization of Pc 4 within different organelles, linear correlation coefficients from the fluorescence data of Pc 4 and the organelle-specific dyes were calculated. Using this measurement, the subcellular spatial distributions of Pc 4 could be successfully monitored over an 18 h period. At early times (0-1 h) after introduction of Pc 4 to LY-R cells, the dye was found in the mitochondria, lysosomes and Golgi apparatus, as well as other cytoplasmic membranes, but not in the plasma membrane or the nucleus. Over the next 2 h, there was some loss of Pc 4 from the lysosomes as shown by the correlation coefficients. After an additional incubation period of 2 h Pc 4 slowly increased its accumulation in the lysosomes. The highest correlation coefficient (0.65) was for Pc 4 and BODIPY-FL C5 ceramide, which targets the Golgi apparatus, and also binds to other cytoplasmic membranes. The correlation coefficient was also high (0.60) for Pc 4 and a mitochondria-targeting dye (Mitotracker Green FM). Both of these correlation coefficients were higher than that for Pc 4 with the lysosome-targeting dye (Lysotracker Green DND-26). The results suggest that Pc 4 binds preferentially and strongly to mitochondria and Golgi complexes.


Assuntos
Indóis/análise , Linfoma/química , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Fármacos Fotossensibilizantes/análise , Animais , Linfoma/tratamento farmacológico , Linfoma/patologia , Camundongos , Fotoquimioterapia , Células Tumorais Cultivadas
20.
J Biol Chem ; 275(26): 19978-84, 2000 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-10764805

RESUMO

Recent studies have suggested a central role for Ca(2+) in the signaling pathway of apoptosis and certain anti-apoptotic effects of Bcl-2 family of proteins have been attributed to changes in intracellular Ca(2+) homeostasis. Here we report that depletion of Ca(2+) from endoplasmic reticulum (ER) leads to apoptosis in Chinese hamster ovary cells. Stable expression of ryanodine receptor (RyR) in these cells enables rapid and reversible changes of both cytosolic Ca(2+) and ER Ca(2+) content via activation of the RyR/Ca(2+) release channel by caffeine and ryanodine. Sustained depletion of the ER Ca(2+) store leads to apoptosis in Chinese hamster ovary cells, whereas co-expression of Bcl-xL and RyR in these cells prevents apoptotic cell death but not necrotic cell death. The anti-apoptotic effect of Bcl-xL does not correlate with changes in either the Ca(2+) release process from the ER or the capacitative Ca(2+) entry through the plasma membrane. The data suggest that Bcl-xL likely prevents apoptosis of cells at a stage downstream of ER Ca(2+) release and capacitative Ca(2+) entry.


Assuntos
Apoptose/efeitos dos fármacos , Cafeína/farmacologia , Cálcio/metabolismo , Retículo Endoplasmático/metabolismo , Inibidores de Fosfodiesterase/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Rianodina/farmacologia , Animais , Western Blotting , Células CHO , Canais de Cálcio/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Quelantes/farmacologia , Cromatina/efeitos dos fármacos , Cricetinae , Citosol/metabolismo , DNA Complementar/metabolismo , Relação Dose-Resposta a Droga , Ácido Egtázico/análogos & derivados , Ácido Egtázico/farmacologia , Microscopia Confocal , Músculo Esquelético/metabolismo , Necrose , Plasmídeos , Coelhos , Fatores de Tempo , Transfecção , Proteína bcl-X
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