RESUMO
BACKGROUND: Hepatocellular carcinoma (HCC) remains a deadly disease, with patients' best hope for a cure being liver transplantation; however, access to health care resources, such as donor organs, between ethnic groups has historically been unbalanced. Ensuring equitable access to donor livers is crucial to minimize disparities in HCC outcomes. As a result, we sought to better elucidate the differences in transplantation rates among various ethnic groups. MATERIALS AND METHODS: The National Inpatient Sample (NIS) was utilized to evaluate for disparities in liver transplantation in patients whose primary or secondary diagnosis was recorded as HCC or hepatoma. The study included admissions between 2007 and 2014 to centers with at least 1 documented liver transplant. RESULTS: A total of 7244 transplants were performed over 70,406 weighted admissions. Black race was associated with lower transplantation rates, with an adjusted odds ratio of 0.46 (95% confidence interval: 0.42-0.51, P <0.01) when accounting for a number of possible confounders including socioeconomic and geographic factors. CONCLUSIONS: Our study observed decreased rates of liver transplant in blacks compared with whites for HCC. Furthermore, improved economic status and private insurance had a significantly higher odds ratio for transplantation. Hospital-level studies are needed to clarify confounding factors not apparent in large administrative datasets and help better investigate factors that lead to less optimal transplant rates among blacks. Interventions may include more optimal screening policies and procedures, improved interdisciplinary management, and earlier referrals.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Transplante de Fígado , Humanos , Estados Unidos/epidemiologia , Carcinoma Hepatocelular/cirurgia , Neoplasias Hepáticas/cirurgia , Pacientes Internados , Grupos Raciais , Disparidades em Assistência à SaúdeRESUMO
Management of small cell lung cancer (SCLC) has not changed over the last decades. In more recent years, alterations of DNA repair machinery and other molecular pathways have been identified in SCLC and preclinical data suggest that dysregulation of these pathways might offer new therapeutic opportunities.While immune checkpoint inhibitors (ICIs) have had a major impact on the clinical outcome of several solid tumors, including non-small cell lung cancer, the potential role of ICIs is currently under investigation in SCLC and some promising data are available. However, several clinical and biological hurdles have to be overcome and predictive markers are still eagerly needed. Knowledge of molecular pathways specifically involved in SCLC growth and treatment resistance is essential for a more rational planning of new combinations including ICIs.The present manuscript summarizes the current clinical evidence on immunotherapy in SCLC, describes the molecular bases underlying treatment resistance and discusses the potentialities and the rationale of different therapeutic combinations.
Assuntos
Imunoterapia/métodos , Neoplasias Pulmonares/tratamento farmacológico , Carcinoma de Pequenas Células do Pulmão/tratamento farmacológico , Humanos , Neoplasias Pulmonares/patologia , Carcinoma de Pequenas Células do Pulmão/patologiaRESUMO
INTRODUCTION: The prognosis of small-cell lung cancer (SCLC) is dismal and new effective therapies are needed. Immunotherapy looks promising, but no molecular predictive markers are currently available, and data on immune microenvironment are very limited. METHODS: We retrospectively analysed 104 SCLC cases. Immunohistochemistry evaluation of PD-L1 was performed both on tumour cells (TCs) and on tumour-infiltrating immune cells (TIICs) by using anti-PD-L1 22C3 antibody (DAKO) and categorised by using 1% as cut-off point. Tumour-infiltrating lymphocytes (TILs) were characterised by using anti-CD8 and anti-FOXP3 antibodies. Semi-quantitative score was used and categorised as positive versus negative/low. The relation of molecular markers with prognosis and with clinical variables was evaluated. RESULTS: The analysis included 66 stage I-III patients (48 surgically resected, 18 treated with radical-intent chemoradiotherapy) and 38 metastatic cases. In the overall study population, PD-L1 was expressed on TCs and TIICs in 25% and 40% of cases, respectively. The proportion of PD-L1-positive cases was significantly higher in stage I-III versus metastatic patients (32% versus 13%, p: 0.034 for TCs; 51.5% versus 21% for TIICs, p: 0.002). CD8- and FOXP3-positive TILs were present in 59% and 72% of samples, respectively. The presence of FOXP3-TILs was associated with improved prognosis among non-metastatic patients, with a hazard ratio for survival of 0.32 (95% confidence interval [CI]: 0.16-0.7, p: 0.006) for univariate analysis, and 0.37 (95% CI: 0.17-0.81, p: 0.013) for multivariate analysis. CONCLUSIONS: Immune contexture of SCLC may differ according to stage. The presence of FOXP3-positive TILs is a potential prognostic marker for stage I-III SCLCs and warrants further investigation.
Assuntos
Antígeno B7-H1/imunologia , Fatores de Transcrição Forkhead/imunologia , Neoplasias Pulmonares/imunologia , Carcinoma de Pequenas Células do Pulmão/imunologia , Microambiente Tumoral/imunologia , Idoso , Idoso de 80 Anos ou mais , Antígeno B7-H1/biossíntese , Feminino , Fatores de Transcrição Forkhead/biossíntese , Humanos , Estimativa de Kaplan-Meier , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/terapia , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estadiamento de Neoplasias , Prognóstico , Estudos Retrospectivos , Carcinoma de Pequenas Células do Pulmão/metabolismo , Carcinoma de Pequenas Células do Pulmão/terapiaRESUMO
Background: Tumor immune microenvironment (TME) plays a key role in malignant pleural mesothelioma (MPM) pathogenesis and treatment outcome, supporting a role of immune checkpoint inhibitors as anticancer approach. This study retrospectively investigated TME and programmed death ligand 1 (PD-L1) expression in naïve MPM cases and their change under chemotherapy. Patients and methods: Diagnostic biopsies of MPM patients were collected from four Italian and one Slovenian cancer centers. Pathological assessment of necrosis, inflammation, grading, and mitosis was carried out. Ki-67, PD-L1 expression, and tumor infiltrating lymphocytes were detected by immunohistochemistry. When available, the same paired sample after chemotherapy was analyzed. Pathological features and clinical characteristics were correlated to overall survival. Results: TME and PD-L1 expression were assessed in 93 and 65 chemonaive MPM samples, respectively. Twenty-eight samples have not sufficient tumor tissue for PD-L1 expression. Sarcomatoid/biphasic samples were characterized by higher CD8+ T lymphocytes and PD-L1 expression on tumor cells, while epithelioid showed higher peritumoral CD4+ T and CD20+ B lymphocytes. Higher CD8+ T lymphocytes, CD68+ macrophages, and PD-L1 expression were associated with pathological features of aggressiveness (necrosis, grading, Ki-67). MPM cases characterized by higher CD8+ T-infiltrate showed lower response to chemotherapy and worse survival at univariate analysis. Patients stratification according to a combined score including CD8+ T lymphocytes, necrosis, mitosis, and proliferation index showed median overall survival of 11.3 months compared with 16.4 months in cases with high versus low combined score (P < 0.003). Subgroup exploratory analysis of 15 paired samples before and after chemotherapy showed a significant increase in cytotoxic T lymphocytes in MPM samples and PD-L1 expression in immune cells. Conclusions: TME enriched with cytotoxic T lymphocytes is associated with higher levels of macrophages and PD-L1 expression on tumor cells and with aggressive histopathological features, lower response to chemotherapy and shorter survival. The role of chemotherapy as a tumor immunogenicity inducer should be confirmed in a larger validation set.
Assuntos
Antineoplásicos Imunológicos/uso terapêutico , Antígeno B7-H1/metabolismo , Biomarcadores Tumorais/metabolismo , Neoplasias Pulmonares/patologia , Mesotelioma/patologia , Neoplasias Pleurais/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos Imunológicos/farmacologia , Antígeno B7-H1/imunologia , Biomarcadores Tumorais/imunologia , Biópsia , Feminino , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/mortalidade , Linfócitos do Interstício Tumoral/imunologia , Macrófagos/imunologia , Masculino , Mesotelioma/tratamento farmacológico , Mesotelioma/imunologia , Mesotelioma/mortalidade , Mesotelioma Maligno , Pessoa de Meia-Idade , Índice Mitótico , Pleura/citologia , Pleura/imunologia , Pleura/patologia , Neoplasias Pleurais/tratamento farmacológico , Neoplasias Pleurais/imunologia , Neoplasias Pleurais/mortalidade , Prognóstico , Estudos Retrospectivos , Análise de Sobrevida , Linfócitos T Citotóxicos/imunologia , Resultado do Tratamento , Microambiente Tumoral/efeitos dos fármacos , Microambiente Tumoral/genética , Microambiente Tumoral/imunologiaRESUMO
Postoperative alveolar fistula (AF) associated with pleural cavity (PC) is a serious complication and a therapeutic challenge in thoracic surgery. The purpose of this study was to assess the efficacy of the use of the autologous platelet gel for the treatment of AF and PC. We treated a patient with post lung resection persistent alveolar fistula using a autologous platelet gel, a cellular compose produces at the Division of Immunohaematoligy and Trasfusion. The platelet gel-PRP (Platelet-Rich Plasma) is a biological material made of autologous platelets, extracted from a small amount of the patient's blood, centrifuged at 1100 g for 9 min. The PRP obtained was activated by addition of autologous thrombin and calcium chloride to form a matrix of fibrin (PRFM) thick. The patient presented important air leak after middle lobe wedge resection for solitary lung lesion with standard open decortication for important pleural adhesions post pleuritis. On postoperative day XIII the patient developed a thoracic empyema and consequently underwent a antibiotic pleural irrigation through the chest drainage based on the microbiological analysis of the pleural fluid. After a week we obtained the resolution of the empyema but a residual space remained and air leak persisted. We treated the patient with autologous platelet gel. We administer 7.5 mL of the autologous platelet gel across the chest drainage ever 72 hours for 3 times. After the third application we had the closure of the cavity and the cessation of air leak. Autologous platelet gel is easy to use, safe and inexpensive. It can be considered a valid therapeutic option in selected patients with a alveolar fistula and a lung partial re-expansion. The product consist of a significant amount of cellular components with healing anti-inflammatory an proregenerative properities that permit the body to heal tissue wounds faster and more efficiently. A sterile pleural cavity is fundamental conditions for the final success of the procedure.
Assuntos
Transfusão de Plaquetas , Pneumonectomia/efeitos adversos , Alvéolos Pulmonares , Fístula do Sistema Respiratório/etiologia , Fístula do Sistema Respiratório/terapia , Géis , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
OBJECTIVE: Systemic sclerosis (SSc) is a disorder characterized by vascular damage and fibrosis of the skin and internal organs. Despite marked tissue hypoxia, there is no evidence of compensatory angiogenesis. The ability of mesenchymal stem cells (MSCs) to differentiate into endothelial cells was recently demonstrated. The aim of this study was to determine whether impaired differentiation of MSCs into endothelial cells in SSc might contribute to disease pathogenesis by decreasing endothelial repair. METHODS: MSCs obtained from 7 SSc patients and 15 healthy controls were characterized. The number of colony-forming unit-fibroblastoid colonies was determined. After culture in endothelial-specific medium, the endothelial-like MSC (EL-MSC) phenotype was assessed according to the surface expression of vascular endothelial growth factor receptors (VEGFRs). Senescence, chemoinvasion, and capillary morphogenesis studies were also performed. RESULTS: MSCs from SSc patients displayed the same phenotype and clonogenic activity as those from controls. In SSc MSCs, a decreased percentage of VEGFR-2+, CXCR4+, VEGFR-2+/CXCR4+ cells and early senescence was detected. After culturing, SSc EL-MSCs showed increased expression of VEGFR-1, VEGFR-2, and CXCR4, did not express CD31 or annexin V, and showed significantly decreased migration after specific stimuli. Moreover, the addition of VEGF and stromal cell-derived factor 1 to cultured SSc EL-MSCs increased their angiogenic potential less than that in controls. CONCLUSION: Our data strongly suggest that endothelial repair may be affected in SSc. The possibility that endothelial progenitor cells could be used to increase vessel growth in chronic ischemic tissues may open up new avenues in the treatment of vascular damage caused by SSc.
Assuntos
Diferenciação Celular/fisiologia , Células Endoteliais/fisiologia , Endotélio Vascular/patologia , Células-Tronco Mesenquimais/patologia , Escleroderma Sistêmico/fisiopatologia , Adolescente , Adulto , Estudos de Casos e Controles , Células Cultivadas , Senescência Celular , Quimiocina CXCL12 , Quimiocinas CXC/metabolismo , Endotélio Vascular/metabolismo , Endotélio Vascular/fisiopatologia , Feminino , Humanos , Imunofenotipagem , Masculino , Células-Tronco Mesenquimais/metabolismo , Células-Tronco Mesenquimais/fisiologia , Pessoa de Meia-Idade , Neovascularização Patológica , Fenótipo , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , Receptores CXCR4/metabolismo , Receptores de Fatores de Crescimento do Endotélio Vascular/metabolismo , Escleroderma Sistêmico/patologia , Células-Tronco/metabolismo , Células-Tronco/patologiaRESUMO
Shedding of membrane vesicles is a vital phenomenon frequently observed in tumor cells and suggested to be involved in several aspects of tumor progression. Our previous studies have shown that human breast tumor cells rapidly shed membrane vesicles containing matrix metalloproteinases (MMPs). In this study we present that human umbilical vein endothelial cells (HUVEC) as well as different tumor cell lines (human ovarian cancer, CABA I and A2780, and hepatocarcinoma cell line, SK-Hep 1) shed vesicles in the extracellular medium. These vesicles carry MMPs and their inhibitors TIMPs. We conclude that tumor and endothelial cells shed MMP-containing vesicles and this may represent a mechanism for regulating focalized proteolytic activity and a way to interact with microenvironment during tumor angiogenesis.
Assuntos
Membrana Celular/ultraestrutura , Células Endoteliais/ultraestrutura , Invasividade Neoplásica/ultraestrutura , Neoplasias/irrigação sanguínea , Neovascularização Patológica/patologia , Vesículas Secretórias/ultraestrutura , Carcinoma/irrigação sanguínea , Carcinoma/fisiopatologia , Carcinoma/ultraestrutura , Carcinoma Hepatocelular/irrigação sanguínea , Carcinoma Hepatocelular/fisiopatologia , Carcinoma Hepatocelular/ultraestrutura , Linhagem Celular Tumoral , Membrana Celular/fisiologia , Células Endoteliais/fisiologia , Exocitose/fisiologia , Espaço Extracelular/metabolismo , Feminino , Humanos , Metaloproteinases da Matriz/metabolismo , Microscopia Eletrônica de Varredura , Invasividade Neoplásica/fisiopatologia , Neoplasias/fisiopatologia , Neoplasias/ultraestrutura , Neovascularização Patológica/fisiopatologia , Neoplasias Ovarianas/irrigação sanguínea , Neoplasias Ovarianas/fisiopatologia , Neoplasias Ovarianas/ultraestrutura , Vesículas Secretórias/fisiologia , Inibidores Teciduais de Metaloproteinases/metabolismo , Veias UmbilicaisRESUMO
Plasma membrane lipid microdomains have been considered as a sort of 'closed chamber', where several subcellular activities, including CD95/Fas-mediated proapoptotic signaling, take place. In this work we detected GD3 and GM3 gangliosides in isolated mitochondria from lymphoblastoid CEM cells. Moreover, we demonstrated the presence of microdomains in mitochondria by immunogold transmission electron microscopy. We also showed that GD3, the voltage-dependent anion channel-1 (VDAC-1) and the fission protein hFis1 are structural components of a multimolecular signaling complex, in which Bcl-2 family proteins (t-Bid and Bax) are recruited. The disruption of lipid microdomains in isolated mitochondria by methyl-beta-cyclodextrin prevented mitochondria depolarization induced by GD3 or t-Bid. Thus, mitochondrion appears as a subcompartmentalized organelle, in which microdomains may act as controllers of their apoptogenic programs, including fission-associated morphogenetic changes, megapore formation and function. These results disclose a new scenario in which mitochondria-associated lipid microdomains can act as regulators and catalysts of cell fate.
Assuntos
Apoptose/fisiologia , Gangliosídeo G(M3)/metabolismo , Microdomínios da Membrana/metabolismo , Mitocôndrias/metabolismo , Linfócitos T/metabolismo , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/metabolismo , Humanos , Membranas Intracelulares/metabolismo , Proteínas de Membrana , Microscopia Confocal , Mitocôndrias/efeitos dos fármacos , Proteínas Mitocondriais/metabolismo , Linfócitos T/citologia , Canal de Ânion 1 Dependente de Voltagem/metabolismo , Proteína X Associada a bcl-2/metabolismo , beta-Ciclodextrinas/farmacologia , Receptor fas/metabolismoRESUMO
Paclitaxel (PTX) is a potent anti-neoplastic agent that is highly effective in treating ovarian cancer. Nevertheless, the emergence of PTX resistance has limited the control of this disease. To gain insight into the molecular alterations accompanying drug resistance in ovarian cancer, we generated a new stable PTX-resistant ovarian carcinoma cell line. CABA I cells, which display an intrinsic PTX resistance (IC50 = 800 ng/ml), were subjected to continuous exposure to PTX. From the residual surviving cells, the highly PTX-resistant line CABA-PTX (IC50 = 256000 ng/ml) was generated and stably maintained in vitro. Analysis of beta-tubulin expression indicated that only the HM40 and Hbeta9 isotypes were expressed in both parental and resistant cells. No specific point mutations in the HM40 were detected in either cell line, but expression levels of this isotype were significantly reduced (40%) in CABA-PTX cells. Hbeta9 levels were unchanged. In those cells, PTX resistance was associated with cross-resistance to vinblastine but not to methotrexate or 5-fluorouracil. Verapamil treatment did not reverse the intrinsic drug resistance of parental cells, but partially modulated the sensitivity of CABA-PTX cells to PTX and induced total sensitivity to vinblastine. No changes in the cell surface expression of the drug efflux pumps MRP1, MRP2 and P-glycoprotein were observed. PTX influx, monitored using a fluorescent drug derivative, was significantly reduced and delayed in CABA-PTX cells as compared to the parental cells. Together, these findings suggest that more than one mechanism is involved in PTX resistance, making CABA-PTX cell line a potentially valuable in vitro tool to study multifactorial acquired drug resistance in ovarian cancer.
Assuntos
Resistencia a Medicamentos Antineoplásicos , Neoplasias Ovarianas/tratamento farmacológico , Paclitaxel/farmacologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Antineoplásicos Fitogênicos/farmacologia , Divisão Celular , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Feminino , Citometria de Fluxo , Fluoruracila/farmacologia , Humanos , Concentração Inibidora 50 , Metotrexato/farmacologia , Proteínas Mitocondriais/metabolismo , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Fenótipo , Proteínas Ribossômicas/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Sais de Tetrazólio/farmacologia , Fatores de Tempo , Tubulina (Proteína)/metabolismo , Verapamil/farmacologia , Vimblastina/farmacologiaRESUMO
Ovarian carcinomas represent a major form of gynaecological malignancies, whose treatment consists mainly of surgery and chemotherapy. Besides the difficulty of prognosis, therapy of ovarian carcinomas has reached scarce improvement, as a consequence of lack of efficacy and development of drug-resistance. The need of different biochemical and functional parameters has grown, in order to obtain a larger view on processes of biological and clinical significance. In this paper we report novel metabolic features detected in a series of different human ovary carcinoma lines, by (1)H NMR spectroscopy of intact cells and their extracts. Most importantly, a new ovarian adenocarcinoma line CABA I, showed strong signals in the spectral region between 3.5 and 4.0 p.p.m., assigned for the first time to the polyol sorbitol (39+/-11 nmol/10(6) cells). (13)C NMR analyses of these cells incubated with [1-(13)C]-D-glucose demonstrated labelled-sorbitol formation. The other ovarian carcinoma cell lines (OVCAR-3, IGROV 1, SK-OV-3 and OVCA432), showed, in the same spectral region, intense resonances from other metabolites: glutathione (up to 30 nmol/10(6) cells) and myo-inositol (up to 50 nmol/10(6) cells). Biochemical and biological functions are suggested for these compounds in human ovarian carcinoma cells, especially in relation to their possible role in cell detoxification mechanisms during tumour progression.
Assuntos
Adenocarcinoma/patologia , Biomarcadores Tumorais/análise , Indicadores e Reagentes/farmacocinética , Espectroscopia de Ressonância Magnética , Neoplasias Ovarianas/patologia , Sorbitol/farmacocinética , Progressão da Doença , Feminino , Glutationa/metabolismo , Humanos , Hidrogênio , Células Tumorais CultivadasRESUMO
Efficiency of Fas-mediated apoptosis of lymphoid cells is regulated, among other means, by a mechanism involving its association with ezrin, a cytoskeletal protein belonging to the 4.1 family of proteins. In the present work, we provide evidence for a further molecule that associates to ezrin in Fas-triggered apoptosis, the disialoganglioside GD3. In fact, as an early event, GD3 redistributed in membrane-associated domains in uropods and co-localized with ezrin. Co-immunoprecipitation analyses confirmed this result, indicating a GD3-ezrin association. Altogether, these results are suggestive for a role of GD3 in Fas/ezrin-mediated apoptosis, supporting the view that uropods contain a multimolecular signaling complex involved in Fas-mediated apoptosis.
Assuntos
Apoptose/fisiologia , Gangliosídeos/fisiologia , Fosfoproteínas/metabolismo , Receptor fas/fisiologia , Linhagem Celular , Cromatografia em Camada Fina , Proteínas do Citoesqueleto , Gangliosídeos/metabolismo , Humanos , Microscopia Confocal , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , Testes de PrecipitinaRESUMO
1. Caveolins are integral proteins of glycolipid/cholesterol-rich plasmalemmal caveolae domains, where, they may function as a plasma membrane scaffold onto which many classes of signalling molecules, including receptors and heterotrimeric G proteins, can assemble. To ascertain whether caveolins influence G protein-mediated signal transduction, we stably expressed caveolin-1 and -3 isoforms in the neuroblastoma x glioma NG108-15 hybrid cell line, lacking endogenous caveolins. Subsequently, using whole-cell voltage clamp methods, we examined whether the modulation of N-type voltage-gated Ca2+ channels by G(o) protein-coupled, delta-type opioid receptors might be affected by recombinant caveolin expression. 2. In transfected NG108-15 cells, caveolins localized at the plasma membrane and, upon subcellular fractionation on sucrose density gradients, they co-localized in Triton-resistant, low buoyancy fractions, with endogenous G(o) protein alpha-subunits. 3. The voltage-dependent inhibition of omega-conotoxin GVIA-sensitive Ba2+ currents following either activation of delta-opioid receptors by the agonist [o-pen2,o-pen5]-enkephalin (DPDPE), or direct stimulation of G proteins with guanosine 5'-O-(thiotriphosphate) (GTPgammaS) was significantly attenuated in caveolin-expressing cells. The kinetics of Ca2+ channel inhibition were also modified by caveolins. 4. Overall, these results suggest that caveolins may negatively affect G protein-dependent regulation of voltage-gated N-type Ca2+ channels, presumably by causing a reduction of the available pool of activated G proteins.
Assuntos
Canais de Cálcio Tipo N/metabolismo , Caveolinas/genética , Caveolinas/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Neurônios/fisiologia , Analgésicos Opioides/farmacologia , Animais , Caveolina 1 , Caveolina 3 , Eletrofisiologia , D-Penicilina (2,5)-Encefalina/farmacologia , Expressão Gênica/fisiologia , Glioma , Guanosina 5'-O-(3-Tiotrifosfato)/farmacologia , Células Híbridas , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Neuroblastoma , Ratos , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismoRESUMO
We report that prosaposin treatment induced extracellular signal-regulated kinases (ERKs) and sphingosine kinase activity, increased DNA synthesis, and prevented cell apoptosis. Prosaposin treatment induced pheochromocytoma cells (PC12) to enter the S phase of the cell cycle; this effect was inhibited by the MEK inhibitor PD98059, indicating that prosaposin-induced ERK phosphorylation is required for stimulation of DNA synthesis. The prosaposin effect was also inhibited by pertussis toxin, indicating that the prosaposin receptor is a G-protein-coupled receptor. Prosaposin rescued PC12 cells from apoptosis induced by staurosporine or ceramide. Sphingosine kinase activity was increased by prosaposin treatment. We propose that this effect is a mechanism underlying the proliferative and anti-apoptotic functions of prosaposin. Prosaposin appears to be a key regulatory factor in the ceramide-S-1-P rheostat, which regulates cell fate.
Assuntos
Apoptose/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Glicoproteínas/farmacologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Neoplasias das Glândulas Suprarrenais , Animais , Ciclo Celular/fisiologia , DNA de Neoplasias/biossíntese , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Flavonoides/farmacologia , Fase G1 , Leite , Células PC12 , Toxina Pertussis , Feocromocitoma , Precursores de Proteínas/farmacologia , Ratos , Fase de Repouso do Ciclo Celular , Saposinas , Esfingolipídeos/metabolismo , Fatores de Virulência de Bordetella/farmacologiaRESUMO
Tumor cell ganglioside shedding has been implicated in the process of tumor formation. Previously, we identified three forms of tumor ganglioside shedding: micelles, monomers and membrane vesicles. Here, we have explored the membrane vesicle form of ganglioside shedding, using a newly identified human ovarian carcinoma cell line, CABA I. These cells synthesize and express a spectrum of gangliosides, including the disialoganglioside, G(D3). Immunostaining using the monoclonal antibody R24 confirmed G(D3) expression and its presence in the plasma membrane of these cells. Cellular gangliosides were detected in the culture supernatant by HPTLC autoradiography, confirming an active shedding rate of 3% of cellular gangliosides/24 h. CABA I cell membranes also express caveolin-1, a characteristic protein marker for caveolae, which was detected by flow cytometric analysis and by Western blotting in both the cell membranes and the isolated membrane vesicles. To further define the expression of G(D3) and caveolin-1, we used immunogold electron microscopy. This revealed localization of G(D3) in small clusters in the plasma membrane as well as enrichment and localization of ganglioside G(D3) and caveolin-1 in shed membrane vesicles, with 58-78% of vesicles carrying both G(D3) and caveolin-1. Together, these results suggest that membrane vesicle shedding originates in plasma membrane domains enriched in gangliosides and caveolin-1.
Assuntos
Antígenos Glicosídicos Associados a Tumores/análise , Biomarcadores Tumorais/análise , Caveolinas , Membrana Celular/metabolismo , Gangliosídeos/análise , Proteínas de Membrana/análise , Neoplasias Ovarianas/metabolismo , Caveolina 1 , Feminino , Citometria de Fluxo , Humanos , Imuno-Histoquímica , Microscopia Imunoeletrônica , Células Tumorais CultivadasRESUMO
The aim of this study was to further elucidate our previous observation on molecular interaction of GM3, CD4 and p56Ick in microdomains of human peripheral blood lymphocytes (PBL). We analyzed GM3 distribution by immunoelectron microscopy and the association between GM3 and CD4-p56Ick complex by scanning confocal microscopy and co-immunoprecipitation experiments. Scanning confocal microscopy analysis showed an uneven signal distribution of GM3 molecules over the surface of human lymphocytes. Nearly complete colocalization areas indicated that CD4 molecules were distributed in GM3-enriched plasma membrane domains. Co-immunoprecipitation experiments revealed that CD4 and p56Ick were immunoprecipitated by IgG anti-GM3, demonstrating that GM3 tightly binds to the CD4-p56Ick complex in human PBL. In order to verify whether GM3 association with CD4 molecules may depend on the presence of p56Ick, we analyzed this association in U937, a CD4 + and p56Ick negative cell line. The immunoprecipitation with anti-GM3 revealed the presence of a 58kDa band immunostained with anti-CD4 Ab, suggesting that the GM3-CD4 interaction does not require its association with p56Ick. These findings support the view that GM3 enriched-domains may represent a functional multimolecular complex involved in signal transduction and cell activation.
Assuntos
Antígenos CD4/metabolismo , Linfócitos T CD4-Positivos/metabolismo , Gangliosídeo G(M3)/metabolismo , Proteína Tirosina Quinase p56(lck) Linfócito-Específica/metabolismo , Linhagem Celular , Gangliosídeo G(M3)/imunologia , Humanos , Microscopia Confocal , Testes de PrecipitinaRESUMO
The ability of a cell to modify the extracellular matrix is important in several pathophysiological alterations including tumorigenesis. Cell transformation is accompanied by changes in the surrounding stroma as a result of the action of specific proteases such as the urokinase plasminogen activator (uPA), which has been associated with invasive potential in many tumor types. In this study, we analyzed the release of vesicle-associated uPA by the aggressive prostatic carcinoma cell line PC3 and the implications of this release for the invasive behaviour of prostatic tumor cells. Zymography and Western blot analysis revealed the presence of vesicle-associated uPA in the high-molecular weight form. Vesicles adhered to and degraded both collagen IV and reconstituted basal membrane (Matrigel), and plasminogen enhanced the degradation in a dose-dependent manner. Addition of membrane vesicles shed by PC3 cells to cultures of the poorly invasive prostate cancer cell line LnCaP enhanced the adhesive and invasive capabilities of the latter, suggesting a mechanism involving substrate recognition and degradation. Together, these findings indicate that membrane vesicles can promote tumor invasion and point to the important role of vesicle-associated uPA in the extracellular compartment.
Assuntos
Invasividade Neoplásica/fisiopatologia , Neoplasias da Próstata/patologia , Ativador de Plasminogênio Tipo Uroquinase/fisiologia , Células 3T3 , Animais , Western Blotting , Colágeno/metabolismo , Meios de Cultivo Condicionados , Combinação de Medicamentos , Humanos , Hidrólise , Laminina , Masculino , Camundongos , Microscopia Imunoeletrônica , Neoplasias da Próstata/metabolismo , Proteoglicanas , Células Tumorais CultivadasRESUMO
In this study we analyzed by immunofluorescence, laser confocal microscopy, immunoelectron microscopy and label fracture technique the ganglioside distribution on the plasma membrane of several different cell types: human peripheral blood lymphocytes (PBL), Molt-4 lymphoid cells, and NIH 3T3 fibroblasts, which mainly express monosialoganglioside GM3, and murine NS20Y neuroblastoma cells, which have been shown to express a high amount of monosialoganglioside GM2. Our observations showed an uneven distribution of both GM3 and GM2 on the plasma membrane of all cells, confirming the existence of ganglioside-enriched microdomains on the cell surface. Interestingly, in lymphoid cells the clustered immunolabeling appeared localized over both the microvillous and the nonvillous portions of the membrane. Similarly, in cells growing in monolayer, the clusters were distributed on both central and peripheral regions of the cell surface. Therefore, glycosphingolipid clusters do not appear confined to specific areas of the plasma membrane, implying general functions of these domains, which, as structural components of a cell membrane multimolecular signaling complex, may be involved in cell activation and adhesion, signal transduction and, when associated to caveolae, in endocytosis of specific molecules.
Assuntos
Gangliosídeo G(M2)/química , Gangliosídeo G(M3)/química , Células 3T3 , Animais , Anticorpos Monoclonais , Membrana Celular/química , Membrana Celular/ultraestrutura , Imunofluorescência , Gangliosídeo G(M2)/imunologia , Gangliosídeo G(M3)/imunologia , Humanos , Linfócitos/química , Camundongos , Microscopia Confocal , Microscopia Imunoeletrônica , Polietilenoglicóis , Solubilidade , Células Tumorais CultivadasRESUMO
The in vitro release of matrix-degrading proteinases from breast cancer cells is associated in part with shed membrane vesicles. To determine whether shed vesicles might play a similar role in ovarian cancer cells, we analyzed the shedding phenomenon in vivo and in vitro as well as the enzymatic content of their vesicles. This is the first time that an immunoelectron microscopical analysis revealed membrane vesicles carrying tumor-associated antigen alpha-Folate Receptor (alpha-FR), circulating in biological fluids (ascites and serum) of an ovarian carcinoma patient. These vesicles were trapped in a fiber network with characteristic fibrin periodicity. An ovarian cancer cell line (CABA I) established from ascitic fluid cells of this patient, grew in Matrigel and formed tubular structures suggesting invasive capability. Immunofluorescence analysis demonstrated strong cytoplasmic staining of CABA I cells with anti-matrix metalloproteinase-9 (MMP-9) and anti-urokinase-type plasminogen activator (uPA) antibodies. CABA I cells shed membrane vesicles, which were morphologically similar to those identified in vivo, as determined by electron microscopy. Gelatin zymography of vesicles isolated both in vivo and in vitro revealed major gelatinolytic bands of the MMP family, identified as the zymogen and active forms of gelatinase B (MMP-9) and gelatinase A (MMP-2). By casein-plasminogen zymography we observed high-molecular weight (HMW)-uPA and plasmin bands. Incubation of purified vesicles from CABA I cells with Matrigel led to cleavage of Matrigel components. Taken together, our results point to a possible role of shed vesicles, both in vivo and in vitro, in proteolysis that mediates invasion and spread of ovarian epithelial carcinoma cells.