RESUMO
BACKGROUND: Cancerous inhibitor of protein phosphatase 2A (CIP2A) plays a critical role in the pathogenesis of various types of cancer. Here, we investigated whether manipulating CIP2A abundance could enhance the treatment effects of doxorubicin in MCF-7/ADR cells. METHODS: CIP2A silencing was achieved by specific siRNAs. Proliferation of breast cancer cell line MCF-7/ADR under effective doxorubicin concentrations after CIP2A silencing was examined by MTT assay. Wound healing assay was performed to quantify cell migration and caspase-3/-7 activities were measured for assessing the extent of apoptosis. RESULTS: First, our data confirmed that MCF-7/ADR cell proliferation was suppressed by doxorubicin in a dose-dependent manner. Additionally, knocking down of CIP2A could further decrease MCF-7 cell proliferation and migration, even in the presence of doxorubicin. Mechanistically, we have found that CIP2A silencing promoted cell apoptosis relative to doxorubicin alone or vehicle control groups. Lastly, phosphatase2A (PP2A) activity was potentiated and the autophagy markers, LC3B and Beclin1, were upregulated after knocking down CIP2A. CONCLUSION: Our findings support the potential benefits of using CIP2A inhibitor as a therapeutic agent to treat doxorubicin-resistant breast cancer.
Assuntos
Antibióticos Antineoplásicos/farmacologia , Autoantígenos/genética , Neoplasias da Mama/tratamento farmacológico , Doxorrubicina/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , Inativação Gênica , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas de Membrana/genética , Proteína Fosfatase 2/metabolismo , Apoptose , Autoantígenos/fisiologia , Autofagia , Proteína Beclina-1/metabolismo , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Caspase 3/metabolismo , Caspase 7/metabolismo , Movimento Celular , Proliferação de Células/efeitos dos fármacos , Feminino , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Células MCF-7 , Proteínas de Membrana/fisiologia , Proteínas Associadas aos Microtúbulos/metabolismo , RNA Interferente Pequeno , Regulação para CimaRESUMO
REGγ is a proteasome activator that facilitates the degradation of small peptides. Abnormally high expression of REGγ has been observed in thyroid carcinomas. The purpose of the present study was to explore the role of REGγ in poorly differentiated thyroid carcinoma (PDTC). For this purpose, small interfering RNA (siRNA) was introduced to down-regulate the level of REGγ in the PDTC cell line SW579. Down-regulation of REGγ at the mRNA and protein levels was confirmed by RT-PCR and Western blot analyses. FACS analysis revealed cell cycle arrest at the G1/S transition, the MTT assay showed inhibition of cell proliferation, and the Transwell assay showed restricted cell invasion. Furthermore, the expression of the p21 protein was increased, the expression of proliferating cell nuclear antigen (PCNA) protein decreased, and the expression of the p27 protein was unchanged as shown by Western blot analyses. REGγ plays a critical role in the cell cycle, proliferation and invasion of SW579 cells. The alteration of p21 and PCNA proteins related to the down-regulation of REGγ suggests that p21 and PCNA participate in the process of REGγ regulation of cell cycle progression and cell proliferation. Thus, targeting REGγ has a therapeutic potential in the management of PDTC patients.
Assuntos
Humanos , Autoantígenos/fisiologia , /metabolismo , Proteínas de Neoplasias/fisiologia , Antígeno Nuclear de Célula em Proliferação/metabolismo , Complexo de Endopeptidases do Proteassoma/fisiologia , Neoplasias da Glândula Tireoide/enzimologia , Autoantígenos/genética , Western Blotting , Linhagem Celular Tumoral , Proliferação de Células , Ciclo Celular/fisiologia , Regulação para Baixo , Citometria de Fluxo , Invasividade Neoplásica/patologia , Proteínas de Neoplasias/genética , Complexo de Endopeptidases do Proteassoma/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , RNA Interferente Pequeno/metabolismo , Neoplasias da Glândula Tireoide/patologiaRESUMO
REGγ is a proteasome activator that facilitates the degradation of small peptides. Abnormally high expression of REGγ has been observed in thyroid carcinomas. The purpose of the present study was to explore the role of REGγ in poorly differentiated thyroid carcinoma (PDTC). For this purpose, small interfering RNA (siRNA) was introduced to down-regulate the level of REGγ in the PDTC cell line SW579. Down-regulation of REGγ at the mRNA and protein levels was confirmed by RT-PCR and Western blot analyses. FACS analysis revealed cell cycle arrest at the G1/S transition, the MTT assay showed inhibition of cell proliferation, and the Transwell assay showed restricted cell invasion. Furthermore, the expression of the p21 protein was increased, the expression of proliferating cell nuclear antigen (PCNA) protein decreased, and the expression of the p27 protein was unchanged as shown by Western blot analyses. REGγ plays a critical role in the cell cycle, proliferation and invasion of SW579 cells. The alteration of p21 and PCNA proteins related to the down-regulation of REGγ suggests that p21 and PCNA participate in the process of REGγ regulation of cell cycle progression and cell proliferation. Thus, targeting REGγ has a therapeutic potential in the management of PDTC patients.
Assuntos
Autoantígenos/fisiologia , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Proteínas de Neoplasias/fisiologia , Antígeno Nuclear de Célula em Proliferação/metabolismo , Complexo de Endopeptidases do Proteassoma/fisiologia , Neoplasias da Glândula Tireoide/enzimologia , Autoantígenos/genética , Western Blotting , Ciclo Celular/fisiologia , Linhagem Celular Tumoral , Proliferação de Células , Regulação para Baixo , Citometria de Fluxo , Humanos , Invasividade Neoplásica/patologia , Proteínas de Neoplasias/genética , Complexo de Endopeptidases do Proteassoma/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , RNA Interferente Pequeno/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Neoplasias da Glândula Tireoide/patologiaRESUMO
Multiple sclerosis (MS) is an autoimmune inflammatory demyelinating disease of the central nervous system (CNS). Most of autoimmune diseases arise by an abnormal activation of the inflammatory response against self-antigens (most of them unknown up to date) as a consequence of dysfunction in peripheral tolerance. Regulatory T-cells are essential for maintaining peripheral tolerance, preventing autoimmune diseases and limiting chronic inflammatory conditions. Based on that knowledge, T-regulatory cells have emerged as a key component of the physiopathology of autoimmune diseases including MS. This review compiles the current knowledge on the role and function of T-regulatory cells in MS, the most prevalent CNS autoimmune disease in humans.
Assuntos
Tolerância Imunológica/fisiologia , Esclerose Múltipla/imunologia , Linfócitos T Reguladores/imunologia , Autoantígenos/fisiologia , Citocinas/fisiologia , Fatores de Transcrição Forkhead/fisiologia , Humanos , Inflamação/imunologia , Linfócitos T Reguladores/classificação , Linfócitos T Reguladores/metabolismoRESUMO
La esclerosis múltiple (EM) es una enfermedad inflamatoria autoinmune desmielinizante del sistema nervioso central (SNC). La mayoría de las enfermedades autoinmunes se originan por la activación anormal de la respuesta inflamatoria contra auto-antígenos (la mayoría de ellos desconocidos a la fecha) como consecuencia de la pérdida de la tolerancia periférica. Las células T-regulatorias constituyen un grupo esencial de linfocitos T encargados del mantenimiento de la tolerancia periférica, la prevención de enfermedades autoinmunes y la limitación de enfermedades inflamatorias crónicas. Teniendo en cuenta la importancia de la tolerancia periférica, las células T-regulatorias serían componentes cruciales en el escenario fisiopatológico de los procesos autoinmunes, incluyendo la EM. El presente trabajo recopila los conocimientos actuales sobre la función de las células T-regulatorias en la EM, la enfermedad autoinmune desmielinizante del SNC más prevalente en los seres humanos.
Multiple sclerosis (MS) is an autoimmune inflammatory demyelinating disease of the central nervous system (CNS). Most of autoimmune diseases arise by an abnormal activation of the inflammatory response against self-antigens (most of them unknown up to date) as a consequence of dysfunction in peripheral tolerance. Regulatory T-cells are essential for maintaining peripheral tolerance, preventing autoimmune diseases and limiting chronic inflammatory conditions. Based on that knowledge, T-regulatory cells have emerged as a key component of the physiopathology of autoimmune diseases including MS. This review compiles the current knowledge on the role and function of T-regulatory cells in MS, the most prevalent CNS autoimmune disease in humans.
Assuntos
Humanos , Tolerância Imunológica/fisiologia , Esclerose Múltipla/imunologia , Linfócitos T Reguladores/imunologia , Autoantígenos/fisiologia , Citocinas/fisiologia , Fatores de Transcrição Forkhead/fisiologia , Inflamação/imunologia , Linfócitos T Reguladores/classificação , Linfócitos T Reguladores/metabolismoRESUMO
Historically, immunology emerged as a biomedical science, concerned with host defense and production of anti-infectious vaccines. In the late 50s, selective theories were proposed and from then on, immunology has been based in a close association with the neo-Darwinian principles, such as random generation of variants (lymphocyte clones), selection by extrinsic factors (antigens) - and, more generally, on genetic determinism and functionalism. This association has had major consequences: (1) immunological jargon is full of "cognitive" metaphors, founded in the idea of "foreignness"; (2) the immune system is described with a random clonal origin, coupled to selection by random encounters; and (3) physiological events are virtually absent from immunological descriptions. In the present manuscript, we apply systemic notions to bring forth an explanation including systemic mechanisms able to generate immunological phenomena. We replace "randomness plus selection" and the notion of foreignness by a history of structural changes which are determined by the coherences of the system internal architecture at any given moment. The importance of this systemic way of seeing is that it explicitly attends to the organization that defines the immune system, within which it is possible to describe the conservative physiology of the immune system. Understanding immune physiology in a systemic way of seeing also suggests mechanisms underlying the origin of immunopathogeny and therefore suggests new insights to therapeutic approaches. However, if seriously acknowledged, this systemic/historic approach to immunology goes along with a global conceptual change which modifies virtually everything in the domain of biology, as suggested by Maturana.
Assuntos
Autoanticorpos/fisiologia , Sistema Imunitário/fisiologia , Animais , Reações Antígeno-Anticorpo/imunologia , Reações Antígeno-Anticorpo/fisiologia , Autoanticorpos/imunologia , Autoantígenos/imunologia , Autoantígenos/fisiologia , Humanos , Sistema Imunitário/imunologia , Tolerância ImunológicaRESUMO
Current immunological opinion disdains the necessity to define global interconnections between lymphocytes and regards natural autoantibodies and autoreactive T cells as intrinsically pathogenic. Immunological theories address the recognition of foreignness by independent clones of lymphocytes, not the relations among lymphocytes or between lymphocytes and the organism. However, although extremely variable in cellular/molecular composition, the immune system preserves as invariant a set of essential relations among its components and constantly enacts contacts with the organism of which it is a component. These invariant relations are reflected, for example, in the life-long stability of profiles of reactivity of immunoglobulins formed by normal organisms (natural antibodies). Oral contacts with dietary proteins and the intestinal microbiota also result in steady states that lack the progressive quality of secondary-type reactivity. Autoreactivity (natural autoantibody and autoreactive T cell formation) is also stable and lacks the progressive quality of clonal expansion. Specific immune responses, currently regarded as the fundament of the operation of the immune system, may actually result from transient interruptions in this stable connectivity among lymphocytes. More permanent deficits in interconnectivity result in oligoclonal expansions of T lymphocytes, as seen in Omenn's syndrome and in the experimental transplantation of a suboptimal diversity of syngeneic T cells to immunodeficient hosts, which also have pathogenic consequences. Contrary to theories that forbid autoreactivity as potentially pathogenic, the physiology of the immune system is conservative and autoreactive. Pathology derives from failures of these conservative mechanisms.
Assuntos
Sistema Imunitário/fisiologia , Animais , Reações Antígeno-Anticorpo/imunologia , Reações Antígeno-Anticorpo/fisiologia , Autoanticorpos/imunologia , Autoanticorpos/fisiologia , Autoantígenos/imunologia , Autoantígenos/fisiologia , Humanos , Sistema Imunitário/imunologia , Modelos Imunológicos , Linfócitos T/imunologia , Linfócitos T/fisiologiaRESUMO
O bócio difuso tóxico, a oftalmopatia e o mixedema pré-tibial constituem a tríade clássica da doença de Graves. A inexistência de um modelo animal, além do difícil acesso aos tecidos-alvos, torna complexa a investigaçao etiopatogênica da oftalmopatia. Existem fortes evidências de que a oftalmopatia de Graves está intrinsecamente ligada ao processo auto-imune da tireóide. Porém o mecanismo de sua patogênese continua obscuro. Nao se encontraram ainda auto-anticorpos específicos e nem uma predisposiçao imunogenética consistente com a presença da oftalmopatia. Além disso, a participaçao de auto-antígenos tem sido de difícil comprovaçao, embora uma candidata provável seja a proteína 72 KDa, presente nas células foliculares da tireóide. Parece, contudo, que o mecanismo patogênico primário na oftalmopatia seria a estimulaçao de fibroblastos, resultante de citocininas linfocitárias. O fato de o acometimento do tecido conjuntivo limitar-se primariamente à órbita e à regiao pré-tibial ainda nao foi esclarecido. Uma provável explicaçao seria a possibilidade de os fibroblastos nessas regioes diferirem fenotipicamente dos fibroblastos de outras regioes. A oftalmopatia está presente clinicamente em 25 por cento a 50 por cento dos pacientes com doença de Graves e hipertireoidismo, ocorrendo ocasionalmente na tireoidite de Hashimoto e raramente na doença de Plummer e no bócio multinodular tóxico. Embora muitos pacientes com hipertireoidismo de Graves nao apresentem evidências clínicas de oftalmopatia, o uso de métodos diagnósticos por imagem - como, p.ex., ultra-sonografia, tomografia computadorizada e a ressonância magnética da órbita - comprova o envolvimento ocular na maioria dos pacientes. Outra importante observaçao é que aproximadamente 10 por cento dos pacientes com oftalmopatia nao apresentam hipertireoidismo, embora a maioria apresente evidências laboratoriais de doença auto-imune da tireóide (anticorpo antiperoxidase ou anticorpo anti-receptor TSH). Em adiçao, existe uma relaçao direta entre o início do hipertireoidismo e da oftalmopatia. Independente de qual comece primeiro, o outro se desenvolverá em 18 meses em 85 por cento dos pacientes afetados 10). Achados histopatológicos do tecido orbitário dos pacientes com oftalmopatia de Graves sugerem dois mecanismos patológicos (5,l1):1.Processo inflamatório da musculatura extra-ocular, com infiltrado linfocitário e edema. 2.Proliferaçao dos tecidos adiposo e conjuntivo. Sisson (l5), através de cultura de fibroblastos retroorbitários, demonstrou que linfócitos de pacientes com oftalmopatia de Graves podem estimular a síntese de glicosaminoglicans. Além disso, também foi observado que imunoglobulinas de pacientes com oftalmopatia podem estimular essa mesma síntese. Bolonkin et al.(4) demonstraram a presença de receptor de TSH no tecido retroorbitário, sugerindo que anticorpos estimulantes da...