Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 35
Filtrar
1.
EMBO Rep ; 23(12): e55839, 2022 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-36268590

RESUMO

ZBP1 is an interferon-induced cytosolic nucleic acid sensor that facilitates antiviral responses via RIPK3. Although ZBP1-mediated programmed cell death is widely described, whether and how it promotes inflammatory signaling is unclear. Here, we report a ZBP1-induced inflammatory signaling pathway mediated by K63- and M1-linked ubiquitin chains, which depends on RIPK1 and RIPK3 as scaffolds independently of cell death. In human HT29 cells, ZBP1 associated with RIPK1 and RIPK3 as well as ubiquitin ligases cIAP1 and LUBAC. ZBP1-induced K63- and M1-linked ubiquitination of RIPK1 and ZBP1 to promote TAK1- and IKK-mediated inflammatory signaling and cytokine production. Inhibition of caspase activity suppressed ZBP1-induced cell death but enhanced cytokine production in a RIPK1- and RIPK3 kinase activity-dependent manner. Lastly, we provide evidence that ZBP1 signaling contributes to SARS-CoV-2-induced cytokine production. Taken together, we describe a ZBP1-RIPK3-RIPK1-mediated inflammatory signaling pathway relayed by the scaffolding role of RIPKs and regulated by caspases, which may induce inflammation when ZBP1 is activated below the threshold needed to trigger a cell death response.


Assuntos
Morte Celular , Proteínas de Ligação a RNA , Proteína Serina-Treonina Quinases de Interação com Receptores , Humanos , Citocinas , Proteína Serina-Treonina Quinases de Interação com Receptores/genética , Transdução de Sinais , Ubiquitina , Proteínas de Ligação a RNA/genética , Células HT29 , Inflamação
2.
Cell Mol Life Sci ; 77(21): 4315-4324, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32367191

RESUMO

Epstein-Barr virus (EBV) was the first human tumor virus being discovered and remains to date the only human pathogen that can transform cells in vitro. 55 years of EBV research have now brought us to the brink of an EBV vaccine. For this purpose, recombinant viral vectors and their heterologous prime-boost vaccinations, EBV-derived virus-like particles and viral envelope glycoprotein formulations are explored and are discussed in this review. Even so, cell-mediated immune control by cytotoxic lymphocytes protects healthy virus carriers from EBV-associated malignancies, antibodies might be able to prevent symptomatic primary infection, the most likely EBV-associated pathology against which EBV vaccines will be initially tested. Thus, the variety of EBV vaccines reflects the sophisticated life cycle of this human tumor virus and only vaccination in humans will finally be able to reveal the efficacy of these candidates. Nevertheless, the recently renewed efforts to develop an EBV vaccine and the long history of safe adoptive T cell transfer to treat EBV-associated malignancies suggest that this oncogenic γ-herpesvirus can be targeted by immunotherapies. Such vaccination should ideally implement the very same immune control that protects healthy EBV carriers.


Assuntos
Infecções por Vírus Epstein-Barr/prevenção & controle , Herpesvirus Humano 4/imunologia , Vacinas contra Herpesvirus/uso terapêutico , Animais , Anticorpos Neutralizantes/imunologia , Infecções por Vírus Epstein-Barr/imunologia , Vacinas contra Herpesvirus/imunologia , Humanos , Vacinação , Vacinas de Partículas Semelhantes a Vírus/imunologia , Vacinas de Partículas Semelhantes a Vírus/uso terapêutico , Proteínas do Envelope Viral/imunologia , Proteínas do Envelope Viral/uso terapêutico
3.
Health Soc Work ; 44(4): 249-258, 2019 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-31665312

RESUMO

This study examined the association between state-specific firearm control policies and firearm suicide rates among men after adjusting for state-level demographics. This cross-sectional study used state-level mortality data from the Centers for Disease Control and Prevention's Web-based Injury Statistics Query and Reporting System and the Brady Campaign State Scorecard in 2017. An age-stratified (15-24 years, 25-44 years, 45-64 years, and ≥ 65 years) multivariable analysis was conducted to identify gun control policies that are associated with firearm suicide rates among men in each age group. Results indicate that the associations of specific firearm control policies and firearm suicide rates differ across the age span. In particular, more policies (for example, dealer regulations and waiting periods) are negatively associated with firearm suicide rate among men 15 to 24 years of age. The findings underscore the importance of designing gender- and age-specific policy advocacy programs directed at lowering the rate of firearm suicide. This study also suggests that California, known for its innovative gun safety legislation efforts, could serve as a model for other states starting preventive programs to reduce the firearm suicide rate. Implications of the findings for social work practice are discussed.


Assuntos
Armas de Fogo/legislação & jurisprudência , Política Pública , Suicídio/estatística & dados numéricos , Adolescente , Adulto , Fatores Etários , Idoso , California , Estudos Transversais , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
4.
J Child Sex Abus ; 26(8): 957-969, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28753119

RESUMO

In a country without a mandatory child abuse reporting system, advocacy for child welfare law can be a tedious and difficult process. This article documents a 10-year advocacy journey based on the capacity-building concept in social sustainability theory which aims to: raise public awareness of child sexual abuse, provide an idea for branding an inquiry column, and connect advocacy efforts to law reforms. Over the past decade in Hong Kong, a total of 336 public inquiries were anonymously sent to Wu Miu Column and published in three local major newspapers. Among these inquiries, 131 inquiries involved child sexual abuse that the "affected individuals" were molested in school or at home and knew the abusers but did not report their cases to child protection services. Inquirers reported more male than female abusers. Proportionally and significantly, female abusers tended to abuse younger children, compared to male abusers who tended to abuse older children. Many abusers were minors who abused younger children, which explains people's reluctance to report the abuse to child protection services. The discovery of this underage phenomenon motivated child advocates to challenge the common law presumption that a boy under the age of 14 is incapable of sexual intercourse. Social workers in this advocacy journey must sustain continuous efforts to prevent youth from becoming future perpetrators.


Assuntos
Fortalecimento Institucional , Abuso Sexual na Infância/prevenção & controle , Defesa da Criança e do Adolescente , Serviços de Proteção Infantil , Adolescente , Criança , Feminino , Hong Kong , Humanos , Masculino
5.
J Aging Soc Policy ; 28(4): 233-45, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27027854

RESUMO

A central objective of the Surgeon General's National Strategy for Suicide Prevention is to focus on older adults. We review individual risk-factors for suicide in late life and then introduce an ecological model to expand conceptualization of elder suicide. We first look at the role of firearms, providing evidence that firearm availability increases the means of elder suicide and gun access policies can contribute to reducing risk. Next, we focus on primary care providers, documenting how older adults often come into contact with these professionals before ending their lives and how these providers could take a more active role in mediating individual-level risk factors. We then turn our attention to the intersection between gun access and primary care and consider how advancing standards of care concerning gun access and suicide risk might be an effective policy alternative for blocking the pathway to suicide among older adults.


Assuntos
Armas de Fogo/legislação & jurisprudência , Atenção Primária à Saúde , Política Pública , Prevenção do Suicídio , Suicídio/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Estados Unidos/epidemiologia
6.
Blood ; 121(9): 1584-94, 2013 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-23297134

RESUMO

DEC-205 is a type I transmembrane multilectin receptor that is predominantly expressed on dendritic cells (DCs). Therefore, previous studies primarily focused on processing of DEC-205­targeted antigens by this potent antigen presenting cell type. Here we show that Epstein-Barr virus (EBV) transformed lymphoblastoid B-cell lines (LCLs) not only express DEC-205 at similar levels to DCs, but also efficiently present targeted EBV nuclear antigen 1 (EBNA1) and EBV-latent membrane protein 1 (LMP1) to EBNA1- and LMP1-specific CD4+ and CD8+ T-cell clones in vitro. Targeting of antigens to DEC-205 on B cells led to more efficient MHC class II than I loading, and stimulated T cells more efficiently than targeting to DEC-205 on DCs. Although LCLs internalized DEC-205­targeted antigens less efficiently than DCs, they retained them for longer time periods and delivered them to endosomal compartments that receive also B-cell receptor targeted proteins. This could facilitate prolonged T-cell stimulation and efficient MHC class II loading, and, indeed, CD4+ T-cell expansion by DEC-205­targeted vaccination was significantly compromised in B-cell deficient mice. These studies suggest that B cells, activated by virus transformation or other means, can contribute to T-cell stimulation after DEC-205 targeting of antigens during vaccination.


Assuntos
Antígenos CD/metabolismo , Linfócitos B/imunologia , Linfócitos B/virologia , Células Dendríticas/imunologia , Herpesvirus Humano 4/fisiologia , Lectinas Tipo C/metabolismo , Receptores de Superfície Celular/metabolismo , Linfócitos T/imunologia , Animais , Apresentação de Antígeno/fisiologia , Antígenos CD/imunologia , Linfócitos B/metabolismo , Linhagem Celular Transformada , Transformação Celular Viral/imunologia , Células Cultivadas , Células Dendríticas/fisiologia , Herpesvirus Humano 4/imunologia , Lectinas Tipo C/imunologia , Ativação Linfocitária/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Antígenos de Histocompatibilidade Menor , Terapia de Alvo Molecular , Receptores de Antígenos de Linfócitos B/imunologia , Receptores de Antígenos de Linfócitos B/metabolismo , Receptores de Superfície Celular/imunologia , Linfócitos T/metabolismo , Linfócitos T/fisiologia , Vacinação/métodos
7.
Blood ; 121(25): 5034-44, 2013 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-23482932

RESUMO

Functional differences between human dendritic cell (DC) subsets and the potential benefits of targeting them with vaccines remain poorly defined. Here we describe that mice with reconstituted human immune system components (huNSG mice) develop all human conventional and plasmacytoid DC compartments in lymphoid organs. Testing different Toll-like receptor agonists for DC maturation in vivo, we found that IL-12p70 and interferon (IFN)-α production correlated with the maturation of CD141+ (BDCA3+) conventional DCs in huNSG mice. Furthermore, depletion of CD141+ DCs before stimulation significantly reduced IFN-α levels in vivo. This DC subset produced similar total amounts but different subtypes of IFN-α in response to synthetic double-stranded RNA compared with plasmacytoid DCs in response to a single-stranded RNA equivalent. Moreover, synthetic double-stranded RNA as adjuvant and antigen targeting to the endocytic receptor DEC-205, a combination that focuses antigen presentation for T-cell priming on CD141+ DCs, stimulated antigen-specific human CD4+ T-cell responses. Thus, the human CD141+ DC subset is a prominent source of IFN-α and interleukin-12 production and should be further evaluated for vaccine development.


Assuntos
Antígenos CD/imunologia , Células Dendríticas/imunologia , Interferon-alfa/biossíntese , Lectinas Tipo C/imunologia , Ativação Linfocitária/imunologia , RNA de Cadeia Dupla/imunologia , Receptores de Superfície Celular/imunologia , Animais , Apresentação de Antígeno/imunologia , Linfócitos T CD8-Positivos/imunologia , Células Dendríticas/citologia , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Humanos , Interferon-alfa/imunologia , Camundongos , Antígenos de Histocompatibilidade Menor
8.
Eur J Immunol ; 43(9): 2246-54, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23913412

RESUMO

Despite many theoretical incompatibilities between mouse and human cells, mice with reconstituted human immune system components contain nearly all human leukocyte populations. Accordingly, several human-tropic pathogens have been investigated in these in vivo models of the human immune system, including viruses such as human immunodeficiency virus (HIV) and Epstein-Barr virus (EBV), as well as bacteria such as Mycobacterium tuberculosis and Salmonella enterica Typhi. While these studies initially aimed to establish similarities in the pathogenesis of infections between these models and the pathobiology in patients, recent investigations have provided new and interesting functional insights into the protective value of certain immune compartments and altered pathology upon mutant pathogen infections. As more tools and methodologies are developed to make these models more versatile to study human immune responses in vivo, such improvements build toward small animal models with human immune components, which could predict immune responses to therapies and vaccination in human patients.


Assuntos
Infecções por Vírus Epstein-Barr/imunologia , Infecções por HIV/imunologia , Leucócitos/imunologia , Tuberculose/imunologia , Febre Tifoide/imunologia , Animais , Modelos Animais de Doenças , HIV-1/imunologia , Herpesvirus Humano 4/imunologia , Humanos , Camundongos , Mycobacterium tuberculosis/imunologia , Salmonella typhi/imunologia
9.
J Virol ; 87(10): 5340-50, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23449805

RESUMO

Evasion of immune T cell responses is crucial for persistent viruses to establish a normal carrier state. Most studies on active immune modulation mechanisms have focused on the stage of virus production in infected cells, when large numbers of viral antigens and potential immune modulators are expressed. For oncogenic viruses such as Kaposi's sarcoma-associated herpesvirus (KSHV), which is carried as a lifelong infection, usually with little harmful effect, but can cause various tumors, the immune evasion strategies can also be relevant in the context of tumorigenesis. Here we report that the virus-encoded interferon regulatory factor 3 (vIRF3) latent viral gene expressed in KSHV-related tumors functions as a potent immunevasin. Expression of vIRF3 downregulates surface major histocompatibility complex class II (MHC-II) DR expression with slow kinetics but, more importantly, can substantially inhibit recognition by KSHV-specific CD4 T cells prior to its effects on MHC-II DR downregulation in model cell systems. This property of vIRF3 is only partly due to its ability to inhibit the transcription of CIITA and, thus, MHC-II expression; CIITA-independent inhibition of MHC-II transcripts and another as yet unidentified posttranscriptional mechanism are also involved in qualitatively modulating the availability of specific peptide/MHC-II complexes at the cell surface. Consistent with these observations, the vIRF3-expressing KSHV-associated primary effusion lymphoma (PEL) lines are generally resistant to recognition by KSHV-specific CD4 T cells. Interestingly, some PEL lines exhibit small subpopulations with lower vIRF3 expression that can be recognized. These data implicate vIRF3 as a critical determinant of the MHC-II antigen presentation function in KSHV-associated PELs that is likely to be important in the pathogenesis of these tumors.


Assuntos
Apresentação de Antígeno , Herpesvirus Humano 8/patogenicidade , Antígenos de Histocompatibilidade Classe II/metabolismo , Interações Hospedeiro-Patógeno , Evasão da Resposta Imune , Fatores Reguladores de Interferon/metabolismo , Transativadores/antagonistas & inibidores , Proteínas Virais/metabolismo , Transformação Celular Neoplásica , Regulação para Baixo , Herpesvirus Humano 8/imunologia , Antígenos de Histocompatibilidade Classe II/biossíntese , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos
10.
Hum Vaccin Immunother ; 20(1): 2331486, 2024 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-38564321

RESUMO

Cancer is a global health challenge, with changing demographics and lifestyle factors producing an increasing burden worldwide. Screening advancements are enabling earlier diagnoses, but current cancer immunotherapies only induce remission in a small proportion of patients and come at a high cost. Cancer vaccines may offer a solution to these challenges, but they have been mired by poor results in past decades. Greater understanding of tumor biology, coupled with the success of vaccine technologies during the COVID-19 pandemic, has reinvigorated cancer vaccine development. With the first signs of efficacy being reported, cancer vaccines may be beginning to fulfill their potential. Solid tumors, however, present different hurdles than infectious diseases. Combining insights from previous cancer vaccine clinical development and contemporary knowledge of tumor immunology, we ask: who are the 'right' patients, what are the 'right' targets, and which are the 'right' modalities to maximize the chances of cancer vaccine success?


Assuntos
COVID-19 , Vacinas Anticâncer , Neoplasias , Humanos , Pandemias , Neoplasias/prevenção & controle , COVID-19/prevenção & controle , Saúde Global , Imunoterapia/métodos
11.
Proc Natl Acad Sci U S A ; 107(5): 2165-70, 2010 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-20133861

RESUMO

Whereas exogenously acquired proteins are the major source of antigens feeding the MHC class II pathway in antigen-presenting cells, some endogenously expressed antigens also access that pathway but the rules governing such access are poorly understood. Here we address this using Epstein-Barr virus (EBV)-coded nuclear antigen EBNA1, a protein naturally expressed in EBV-infected B lymphoblastoid cell lines (LCLs) and a source of multiple CD4(+) T cell epitopes. Using CD4(+) T cell clones against three indicator epitopes, we find that two epitopes are weakly displayed on the LCL surface whereas the third is undetectable, a pattern of limited epitope presentation that is maintained even when nuclear expression of EBNA1 is induced to high supraphysiological levels. Inhibitor and siRNA studies show that, of the two epitopes weakly presented under these conditions, one involves macroautophagy, and the second involves antigen delivery to the MHC II pathway by another endogenous route. In contrast, when EBNA1 is expressed as a cytoplasmic protein, all three CD4 epitopes are processed and presented much more efficiently, and all involve macroautophagy. We conclude that EBNA1's nuclear location limits its accessibility to the macroautophagy pathway and, in consequence, limits the level and range of EBNA1 CD4 epitopes naturally displayed on the infected cell surface.


Assuntos
Autofagia/imunologia , Antígenos CD4/metabolismo , Antígenos Nucleares do Vírus Epstein-Barr/metabolismo , Apresentação de Antígeno , Linfócitos B/citologia , Linfócitos B/imunologia , Linfócitos B/virologia , Linhagem Celular , Núcleo Celular/imunologia , Núcleo Celular/virologia , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/metabolismo , Antígenos Nucleares do Vírus Epstein-Barr/genética , Antígenos HLA-DR/metabolismo , Herpesvirus Humano 4/imunologia , Humanos
12.
Cell Rep ; 42(6): 112599, 2023 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-37279110

RESUMO

Therapeutic neoantigen cancer vaccines have limited clinical efficacy to date. Here, we identify a heterologous prime-boost vaccination strategy using a self-assembling peptide nanoparticle TLR-7/8 agonist (SNP) vaccine prime and a chimp adenovirus (ChAdOx1) vaccine boost that elicits potent CD8 T cells and tumor regression. ChAdOx1 administered intravenously (i.v.) had 4-fold higher antigen-specific CD8 T cell responses than mice boosted by the intramuscular (i.m.) route. In the therapeutic MC38 tumor model, i.v. heterologous prime-boost vaccination enhances regression compared with ChAdOx1 alone. Remarkably, i.v. boosting with a ChAdOx1 vector encoding an irrelevant antigen also mediates tumor regression, which is dependent on type I IFN signaling. Single-cell RNA sequencing of the tumor myeloid compartment shows that i.v. ChAdOx1 reduces the frequency of immunosuppressive Chil3 monocytes and activates cross-presenting type 1 conventional dendritic cells (cDC1s). The dual effect of i.v. ChAdOx1 vaccination enhancing CD8 T cells and modulating the TME represents a translatable paradigm for enhancing anti-tumor immunity in humans.


Assuntos
Linfócitos T CD8-Positivos , Vacinação , Humanos , Camundongos , Animais , Imunidade Adaptativa , Vetores Genéticos , Adjuvantes Imunológicos
13.
Mol Ther ; 19(8): 1478-86, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21540836

RESUMO

Nonviral vectors present considerable advantages over viral counterparts in gene transfer. However, the poor expression efficiency of the transfected genes poses a challenge for their use in gene therapy, primarily due to the inability of these vectors to overcome various barriers, including the biological barriers. Here, we report that ZNF511-PRAP1 may be involved in the recognition and inactivation of transfected plasmids. ZNF511-PRAP1 is induced by transfection of plasmid DNA and suppresses the transcription of transfected plasmids. It binds directly to the p21 promoter in transfected plasmids but not the endogenous counterpart. Similarly, ZNF511-PRAP1 suppresses the expression of the green fluorescent protein reporter gene on transiently transfected plasmids but not an integrated red fluorescence reporter gene with the same cytomegalovirus (CMV) promoter. Therefore, ZNF511-PRAP1 is able to differentiate between exogenous/nonintegrated and endogenous/integrated DNA. The suppression by ZNF511-PRAP1 is independent of DNA methylation and can be abolished by trichostatin A (TSA) treatment and knockdown of HDAC2 and/or ZNF511-PRAP1. Furthermore, ZNF511-PRAP1 interacts directly with HDAC2. Our results revealed that transfected plasmids are recognized by ZNF511-PRAP1 and suppressed by a repressor complex comprising ZNF511-PRAP1 and HDAC2 and suggest that ZNF511-PRAP1 could play a role as a potential molecular barrier in nonviral transgene expression.


Assuntos
Proteínas de Transporte/metabolismo , Expressão Gênica , Técnicas de Transferência de Genes , Plasmídeos/genética , Proteínas da Gravidez/metabolismo , Fatores de Transcrição/metabolismo , Transgenes/genética , Proteínas de Transporte/genética , Linhagem Celular Tumoral , Inibidor de Quinase Dependente de Ciclina p21/genética , Genes Reporter , Terapia Genética/métodos , Vetores Genéticos , Histona Desacetilase 2/genética , Histona Desacetilase 2/metabolismo , Humanos , Ácidos Hidroxâmicos/farmacologia , Plasmídeos/antagonistas & inibidores , Plasmídeos/metabolismo , Proteínas da Gravidez/genética , Regiões Promotoras Genéticas , RNA Interferente Pequeno/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Fatores de Transcrição/efeitos dos fármacos , Transfecção
14.
Child Adolesc Social Work J ; 39(3): 323-336, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34629703

RESUMO

Globally, Disney animated films integrate education into entertainment for families with children. This study uses the Social Capital Theory as the framework to support its focus on parental attention to children's developmental learning needs. This exploratory study examines how Disney animated movies over the last eight decades portraited parents in the life of the leading child characters. With three inclusion criteria (figure-length, animated, and at least one child being the protagonist), we found 155 films for the general audience released between 1937 and 2020. We read relevant website-posted plots and themes of each selected movie from three major informational websites. Data included the leading child, parents or parental figures, and the central theme of the movie. Most of these 155 stories (n = 97, 61.3%) did not mention the child's biological parents. Half of the 48 parental-presence films projected life in a single-headed family and the main characters' heroic image. The movies released during 2000-2020 showed a higher parental presence than the previous seven vicennial periods. Findings show that families could use Disney animated movies illustrating fantasy and reality. Parents can engage children in discussions about friendship and family relationships after watching a movie. If children continue consuming Disney movies, parental involvement is needed to facilitate discussions of real-life learning to help children develop communication skills.

15.
Cancer Cell ; 40(9): 903-905, 2022 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-36027917

RESUMO

In this issue of Cancer Cell, Awad et al. report a phase 1b clinical trial combining a personalized vaccine NEO-PV-01 with chemotherapy and anti-PD-1 pembrolizumab in first-line metastatic non-squamous NSCLC. They demonstrate that this treatment regimen was well tolerated and induced neoantigen-specific CD4+ T cell responses with effector phenotype.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/patologia , Ensaios Clínicos Fase I como Assunto , Humanos , Neoplasias Pulmonares/patologia , Vacinação
16.
Gastroenterology ; 139(2): 632-43, 643.e1-4, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20347819

RESUMO

BACKGROUND & AIMS: C/EBPalpha (cebpa) is a putative tumor suppressor. However, initial results indicated that cebpa was up-regulated in a subset of human hepatocellular carcinomas (HCCs). The regulation and function of C/EBPalpha was investigated in HCC cell lines to clarify its role in liver carcinogenesis. METHODS: The regulation of C/EBPalpha expression was studied by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), Western blotting, immunohistochemistry, methylation-specific PCR, and chromatin immunoprecipitation assays. C/EBPalpha expression was knocked-down by small interfering RNA or short hairpin RNA. Functional assays included colony formation, methylthiotetrazole, bromodeoxyuridine incorporation, and luciferase-reporter assays. RESULTS: Cebpa was up-regulated at least 2-fold in a subset (approximately 55%) of human HCCs compared with adjacent nontumor tissues. None of the up-regulated samples were positive for hepatitis C infection. The HCC cell lines Hep3B and Huh7 expressed high, PLC/PRF/5 intermediate, HepG2 and HCC-M low levels of C/EBPalpha, recapitulating the pattern of expression observed in HCCs. No mutations were detected in the CEBPA gene in HCCs and cell lines. C/EBPalpha was localized to the nucleus and functional in Hep3B and Huh7 cells; knocking-down its expression reduced target-gene expression, colony formation, and cell growth, associated with a decrease in cyclin A and CDK4 concentrations and E2F transcriptional activity. Epigenetic mechanisms including DNA methylation, and the binding of acetylated histone H3 to the CEBPA promoter-regulated cebpa expression in the HCC cells. CONCLUSIONS: C/EBPalpha is up-regulated in a subset of HCCs and has growth-promoting activities in HCC cells. Novel oncogenic mechanisms involving C/EBPalpha may be amenable to epigenetic regulation to improve treatment outcomes.


Assuntos
Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Carcinoma Hepatocelular/metabolismo , Proliferação de Células , Neoplasias Hepáticas/metabolismo , Western Blotting , Proteínas Estimuladoras de Ligação a CCAAT/genética , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Núcleo Celular/metabolismo , Imunoprecipitação da Cromatina , Ciclina A/metabolismo , Quinase 4 Dependente de Ciclina/metabolismo , Metilação de DNA , Epigênese Genética , Regulação Neoplásica da Expressão Gênica , Células Hep G2 , Histonas/metabolismo , Humanos , Imuno-Histoquímica , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Interferência de RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Regulação para Cima
17.
Immunol Cell Biol ; 89(3): 408-16, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21301484

RESUMO

Many pathogens relevant to human disease do not infect other animal species. Therefore, animal models that reconstitute or harbor human tissues are explored as hosts for these. In this review, we will summarize recent advances to utilize mice with human immune system components, reconstituted from hematopoietic progenitor cells in vivo. Such mice can be used to study human pathogens that replicate in leukocytes. In addition to studying the replication of these pathogens, the reconstituted human immune system components can also be analyzed for initiating immune responses and control against these infections. Moreover, these new animal models of human infectious disease should replicate the reactivity of the human immune system to vaccine candidates and, especially, the adjuvants contained in them, more faithfully.


Assuntos
Sistema Imunitário/imunologia , Imunidade Adaptativa/imunologia , Animais , Humanos , Imunidade Inata/imunologia , Camundongos , Modelos Animais , Vacinação
18.
PLoS Pathog ; 5(12): e1000699, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20019813

RESUMO

Viruses that naturally infect cells expressing both MHC I and MHC II molecules render themselves potentially visible to both CD8+ and CD4+ T cells through the de novo expression of viral antigens. Here we use one such pathogen, the B-lymphotropic Epstein-Barr virus (EBV), to examine the kinetics of these processes in the virally-infected cell, comparing newly synthesised polypeptides versus the mature protein pool as viral antigen sources for MHC I- and MHC II-restricted presentation. EBV-transformed B cell lines were established in which the expression of two cognate EBV antigens, EBNA1 and EBNA3B, could be induced and then completely suppressed by doxycycline-regulation. These cells were used as targets for CD8+ and CD4+ T cell clones to a range of EBNA1 and EBNA3B epitopes. For both antigens, when synthesis was induced, CD8 epitope display rose quickly to near maximum within 24 h, well before steady state levels of mature protein had been reached, whereas CD4 epitope presentation was delayed by 36-48 h and rose only slowly thereafter. When antigen expression was suppressed, despite the persistence of mature protein, CD8 epitope display fell rapidly at rates similar to that seen for the MHC I/epitope half-life in peptide pulse-chase experiments. By contrast, CD4 epitope display persisted for many days and, following peptide stripping, recovered well on cells in the absence of new antigen synthesis. We infer that, in virally-infected MHC I/II-positive cells, newly-synthesised polypeptides are the dominant source of antigen feeding the MHC I pathway, whereas the MHC II pathway is fed by the mature protein pool. Hence, newly-infected cells are rapidly visible only to the CD8 response; by contrast, latent infections, in which viral gene expression has been extinguished yet viral proteins persist, will remain visible to CD4+ T cells.


Assuntos
Antígenos Virais/imunologia , Infecções por Vírus Epstein-Barr/imunologia , Herpesvirus Humano 4/imunologia , Linfócitos T/imunologia , Apresentação de Antígeno , Linfócitos B , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Epitopos/imunologia , Humanos , Fatores de Tempo , Proteínas Virais
19.
PLoS Genet ; 4(7): e1000129, 2008 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-18636107

RESUMO

Successful tumor development and progression involves the complex interplay of both pro- and anti-oncogenic signaling pathways. Genetic components balancing these opposing activities are likely to require tight regulation, because even subtle alterations in their expression may disrupt this balance with major consequences for various cancer-associated phenotypes. Here, we describe a cassette of cancer-specific genes exhibiting precise transcriptional control in solid tumors. Mining a database of tumor gene expression profiles from six different tissues, we identified 48 genes exhibiting highly restricted levels of gene expression variation in tumors (n = 270) compared to nonmalignant tissues (n = 71). Comprising genes linked to multiple cancer-related pathways, the restricted expression of this "Poised Gene Cassette" (PGC) was robustly validated across 11 independent cohorts of approximately 1,300 samples from multiple cancer types. In three separate experimental models, subtle alterations in PGC expression were consistently associated with significant differences in metastatic and invasive potential. We functionally confirmed this association in siRNA knockdown experiments of five PGC genes (p53CSV, MAP3K11, MTCH2, CPSF6, and SKIP), which either directly enhanced the invasive capacities or inhibited the proliferation of AGS cancer cells. In primary tumors, similar subtle alterations in PGC expression were also repeatedly associated with clinical outcome in multiple cohorts. Taken collectively, these findings support the existence of a common set of precisely controlled genes in solid tumors. Since inducing small activity changes in these genes may prove sufficient to potently influence various tumor phenotypes such as metastasis, targeting such precisely regulated genes may represent a promising avenue for novel anti-cancer therapies.


Assuntos
Regulação Neoplásica da Expressão Gênica , Metástase Neoplásica/genética , Metástase Neoplásica/fisiopatologia , Neoplasias/metabolismo , Sobrevida , Animais , Estudos de Coortes , Neoplasias do Colo/genética , Neoplasias do Colo/patologia , Biologia Computacional/métodos , Bases de Dados Factuais , Perfilação da Expressão Gênica , Humanos , Camundongos , Camundongos Nus , Neoplasias/genética , Análise de Sequência com Séries de Oligonucleotídeos , RNA Interferente Pequeno , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Transcrição Gênica , Ensaios Antitumorais Modelo de Xenoenxerto
20.
J Immunother Cancer ; 9(9)2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34479921

RESUMO

BACKGROUND: The clinical benefit of immune checkpoint blockade (ICB) therapy is often limited by the lack of pre-existing CD8+ T cells infiltrating the tumor. In principle, CD8+ T-cell infiltration could be promoted by therapeutic vaccination. However, this remains challenging given the paucity of vaccine platforms able to induce the strong cytotoxic CD8+ T-cell response required to reject tumors. A therapeutic cancer vaccine that induces a robust cytotoxic CD8+ T-cell response against shared tumor antigens and can be combined with ICB could improve the outcome of cancer immunotherapy. METHODS: Here, we developed a heterologous prime-boost vaccine based on a chimpanzee adenovirus (ChAdOx1) and a modified vaccinia Ankara (MVA) encoding MAGE-type antigens, which are tumor-specific shared antigens expressed in different tumor types. The mouse MAGE-type antigen P1A was used as a surrogate to study the efficacy of the vaccine in combination with ICB in murine tumor models expressing the P1A antigen. To characterize the vaccine-induced immune response, we performed flow cytometry and transcriptomic analyses. RESULTS: The ChAdOx1/MVA vaccine displayed strong immunogenicity with potent induction of CD8+ T cells. When combined with anti-Programmed Cell Death Protein 1 (PD-1), the vaccine induced superior tumor clearance and survival in murine tumor models expressing P1A compared with anti-PD-1 alone. Remarkably, ChAdOx1/MVA P1A vaccination promoted CD8+ T-cell infiltration in the tumors, and drove inflammation in the tumor microenvironment, turning 'cold' tumors into 'hot' tumors. Single-cell transcriptomic analysis of the P1A-specific CD8+ T cells revealed an expanded population of stem-like T cells in the spleen after the combination treatment as compared with vaccine alone, and a reduced PD-1 expression in the tumor CD8+ T cells. CONCLUSIONS: These findings highlight the synergistic potency of ChAdOx1/MVA MAGE vaccines combined with anti-PD-1 for cancer therapy, and establish the foundation for clinical translation of this approach. A clinical trial of ChadOx1/MVA MAGE-A3/NY-ESO-1 combined with anti-PD-1 will commence shortly.


Assuntos
Antígenos Heterófilos/efeitos dos fármacos , Inibidores de Checkpoint Imunológico/uso terapêutico , Imunoterapia/métodos , Neoplasias/tratamento farmacológico , Vacinação/métodos , Animais , Feminino , Humanos , Inibidores de Checkpoint Imunológico/farmacologia , Camundongos , Microambiente Tumoral
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA