RESUMO
Malignant melanoma is highly lethal due to its aggressive invasive properties and metastatic dissemination. The transcription factor E2F1 is crucial for melanoma progression through poorly understood mechanisms. Here, we show that the miR-224/miR-452 cluster is significantly increased in advanced melanoma and invasive/metastatic cell lines that express high levels of E2F1. miR-224/miR-452 expression is directly activated by E2F1 through transactivation of the GABRE gene. Ectopic expression of miR-224/miR-452 in less aggressive cells induces EMT and cytoskeletal rearrangements and enhances migration/invasion. Conversely, miR-224/miR-452 depletion in metastatic cells induces the reversal of EMT, inhibition of motility, loss of the invasive phenotype and an absence of lung metastases in mice. We identify the metastasis suppressor TXNIP as new target of miR-224/miR-452 that induces feedback inhibition of E2F1 and show that miR-224/452-mediated downregulation of TXNIP is essential for E2F1-induced EMT and invasion. The E2F1-miR-224/452-TXNIP axis constitutes a molecular signature that predicts patient survival and may help to set novel therapies.
Assuntos
Proteínas de Transporte/metabolismo , Fator de Transcrição E2F1/metabolismo , Transição Epitelial-Mesenquimal/fisiologia , MicroRNAs/metabolismo , Western Blotting , Proteínas de Transporte/genética , Linhagem Celular , Imunoprecipitação da Cromatina , Fator de Transcrição E2F1/genética , Transição Epitelial-Mesenquimal/genética , Imunofluorescência , Humanos , Imuno-Histoquímica , Técnicas In Vitro , Melanoma/metabolismo , MicroRNAs/genéticaRESUMO
Body mass index (BMI) is one of the most important outcome predictors in patients with anorexia nervosa (AN). A low premorbid BMI percentile calculated by the patients recalled premorbid weight and the height at first admission has been found to predict the BMI at first inpatient admission. In this study, we sought to confirm this relationship. We additionally analyze the relationship between premorbid BMI percentile and BMI percentile at discharge from the first inpatient treatment and at 1-year follow-up or alternatively if applicable upon readmission within this time period. We included 161 female patients aged 11-18 years of the multisite ANDI-trial with a DSM-IV diagnosis of AN. We used a multivariate statistical model including the independent variables age, duration of illness, duration of treatment, BMI at admission and BMI percentile at discharge. The relationship between premorbid BMI percentile and BMI at admission was solidly confirmed. In addition to premorbid BMI percentile, BMI at admission and age were significant predictors of BMI percentile at discharge. BMI percentile at discharge significantly predicted BMI percentile at 1-year follow-up. An additional analysis that merely included variables available upon referral revealed that premorbid BMI percentile predicts the 1-year follow-up BMI percentile. Further studies are required to identify the underlying biological mechanisms and to address the respective treatment strategies for AN patients with a low or high premorbid BMI percentile.
Assuntos
Anorexia Nervosa/diagnóstico , Índice de Massa Corporal , Admissão do Paciente , Alta do Paciente , Aumento de Peso , Redução de Peso , Adolescente , Fatores Etários , Anorexia Nervosa/terapia , Peso Corporal , Criança , Feminino , Seguimentos , Humanos , Masculino , Valor Preditivo dos Testes , Prognóstico , Encaminhamento e Consulta , Fatores de TempoRESUMO
The fifth revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) resulted in substantial changes with regard to the classification of Eating Disorders. In DSM-5, Feeding and Eating Disorders are for the first time subsumed in a single category. The Binge Eating Disorder (BED) was established as the third classical eating disorder in addition to Anorexia Nervosa (AN) and Bulimia Nervosa (BN). The criteria for AN changed remarkably, whereas there were only minor changes to the BN criteria. The criteria for BED differ only marginally from the DSM-IV research criteria. There are now subtypes of AN, BN, and BED in the new category "Other Specific Feeding and Eating Disorders." The rest category "Eating Disorders Not Otherwise Specified" has been renamed to "Unspecified Feeding or Eating Disorders." The practicability of the DSM-5 criteria for Eating Disorders, and for AN in particular, for both clinical practice and research remains to be seen.
Assuntos
Manual Diagnóstico e Estatístico de Transtornos Mentais , Transtornos de Alimentação na Infância/classificação , Transtornos de Alimentação na Infância/diagnóstico , Transtornos da Alimentação e da Ingestão de Alimentos/classificação , Transtornos da Alimentação e da Ingestão de Alimentos/diagnóstico , Adolescente , Adulto , Anorexia Nervosa/classificação , Anorexia Nervosa/diagnóstico , Anorexia Nervosa/psicologia , Transtorno da Compulsão Alimentar/classificação , Transtorno da Compulsão Alimentar/diagnóstico , Transtorno da Compulsão Alimentar/psicologia , Bulimia Nervosa/classificação , Bulimia Nervosa/diagnóstico , Bulimia Nervosa/psicologia , Criança , Pré-Escolar , Transtornos da Alimentação e da Ingestão de Alimentos/psicologia , Transtornos de Alimentação na Infância/psicologia , Humanos , Classificação Internacional de Doenças , MasculinoRESUMO
The transcription factor E2F1 exhibits dual properties, acting as a tumor suppressor and oncogene. Cellular stress such as DNA damage or mitogenic signaling leads to the activation of E2F1 as a mediator of apoptosis in the context of a conserved cellular anti-tumorigenic safeguard mechanism. However in highly aggressive chemoresistant tumors like malignant melanoma and prostate/bladder cancer it switches off this role and acts as promoter of cancer progression. Possible reasons for E2F1 mediated aggressiveness are defects in cell death pathways caused by epigenetic inactivation of important tumor suppressor genes, which often occur in late stage cancer and contribute to chemoresistance. Nevertheless exact mechanisms underlying E2Fs role in invasiveness and metastasis are largely unknown. Different reports hint towards the existence of feedback loops between E2F1 and microRNAs (miRNAs or miRs). MiRs are activated by E2F1 and either the transcription factor itself or cellular genes necessary for the growth regulating function of E2F1 are inhibited by different miRNAs. This mutual regulation possibly influences the balance between E2F1s proapoptotic versus prosurvival function. In the following we will summarize some miRNA-E2F1-interactions contributing to a complex regulatory network.
Assuntos
Progressão da Doença , Fator de Transcrição E2F1/metabolismo , Redes Reguladoras de Genes/genética , MicroRNAs/metabolismo , Neoplasias/genética , Neoplasias/patologia , Animais , Apoptose/genética , Fator de Transcrição E2F1/genética , Humanos , MicroRNAs/genéticaRESUMO
We first discuss current diagnostic issues concerning the classification of anorexia nervosa (AN) by reference to the proposed criteria of the fifth version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). We strongly welcome the changes in the latest revision of DSM-5 (update April 2012), which in our opinion partially solve the previously delineated classification problems. Nevertheless, we still miss a standard or reference(s) for the weight criterion including the delineation between a healthy and unhealthy underweight, a better operationalization of observable behaviors including symptoms of disordered eating, readily accessible cognitions and a better allowance for cross-cultural aspects in the proposed DSM-5 classification of AN. In the second part, we review the treatment recommendations of the NICE guidelines for AN, which overall are characterized by a lack of evidence. Nevertheless, NICE recommended an outpatient treatment setting based on one randomized controlled trial with many methodological limitations. A review of the current literature shows that (a) the optimal treatment setting (inpatient vs. outpatient treatment) still is a subject of debate, and (b) the evaluation of treatment costs in AN plays an important role within this discussion. In contrast to the German Guidelines for the Treatment of Eating Disorders, NICE does not offer any specific criteria for the clinician with regard to determining the adequate treatment setting.
Assuntos
Anorexia Nervosa/diagnóstico , Manual Diagnóstico e Estatístico de Transtornos Mentais , Adolescente , Psiquiatria do Adolescente , Assistência Ambulatorial , Anorexia Nervosa/terapia , Criança , Psiquiatria Infantil , Humanos , Pacientes InternadosRESUMO
The conceptualization of anorexia nervosa (AN) depends on the diagnostic criteria. Most patients with teenage onset AN seem to remit within 3-10 years depending on the definitions of recovery. The mortality of adolescent onset anorexia nervosa (AN) has fortunately decreased over the last two decades. Based on randomized controlled trials, we review different treatments including individual and group psychotherapy, family therapy, psychopharmacology, and hormone therapy. Treatment settings vary over time for any individual patient. Despite high rates of inpatient treatment, the respective evidence for effectiveness is meager. In underage patients with severe AN clinical, ethical and legal aspects need to be dealt with systematically if intermittent compulsory treatment is deemed necessary. The prolonged and frequently chronic course of AN often entails therapeutic discontinuity; the transition into adulthood requires a graded therapeutic concept that considers the severity of the disorder, developmental and chronological age, and parental involvement. Finally, we consider future clinical and research options to improve treatment and outcome of this eating disorder.
Assuntos
Anorexia Nervosa/diagnóstico , Anorexia Nervosa/terapia , Adolescente , Adulto , Anorexia Nervosa/mortalidade , Anorexia Nervosa/psicologia , Internação Compulsória de Doente Mental/legislação & jurisprudência , Continuidade da Assistência ao Paciente , Medicina Baseada em Evidências , Feminino , Fidelidade a Diretrizes , Humanos , Estudos Longitudinais , Avaliação de Resultados da Assistência ao Paciente , Ensaios Clínicos Controlados Aleatórios como Assunto , Remissão Espontânea , Análise de Sobrevida , Transição para Assistência do Adulto , Adulto JovemRESUMO
The E2F1 transcription factor enhances apoptosis by DNA damage in tumors lacking p53. To elucidate the mechanism of a potential cooperation between E2F1 and chemotherapy, whole-genome microarrays of chemoresistant tumor cell lines were performed focusing on the identification of cooperation response genes (CRG). This gene class is defined by a synergistic expression response upon endogenous E2F1 activation and drug treatment. Cluster analysis revealed an expression pattern of CRGs similar to E2F1 mono-therapy, suggesting that chemotherapeutics enhance E2F1-dependent gene expression at the transcriptional level. Using this approach as a tool to explore E2F1-driven gene expression in response to anticancer drugs, we identified novel apoptosis genes such as the tumor suppressor TIEG1/KLF10 as direct E2F1 targets. We show that TIEG1/KLF10 is transcriptionally activated by E2F1 and crucial for E2F1-mediated chemosensitization of cancer cells. Our results provide a broader picture of E2F1-regulated genes in conjunction with cytotoxic treatment that allows the design of more rational therapeutics.
Assuntos
Antineoplásicos/farmacologia , Fator de Transcrição E2F1/metabolismo , Fatores de Transcrição de Resposta de Crescimento Precoce/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Fatores de Transcrição Kruppel-Like/genética , Neoplasias/genética , Neoplasias/patologia , Morte Celular/efeitos dos fármacos , Análise por Conglomerados , Perfilação da Expressão Gênica , Humanos , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células Tumorais CultivadasRESUMO
The purpose of this article is to discuss the proposed criteria of the fifth version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) for anorexia nervosa (AN) and to compare these with an alternative proposal which is based on a broader conception of the AN phenotype (Hebebrand and Bulik, in press). The proposed DSM-5 criteria seem to only insufficiently resolve the problems inherent to the current classification of AN because (1) the A criterion does not include a reference to allow the clinician to decide if the (young) patient meets the weight criterion, (2) the AN patient first must have evolved the cognitive capacity for complex abstract reasoning in order to fulfill the criteria B and C (Bravender et al. in Eur Eat Disord Rev 18:79-89, 2010), (3) physical symptoms of starvation including the neuroendocrine dysfunction characteristic of AN are not a diagnostic requirement, and (4) the subtypes are not helpful for classification of younger patients who almost all have the restricting type. On these grounds the proposed DSM-5 criteria will perpetuate the diagnostic tradition of a high percentage of patients who are subsumed under the diagnosis of eating disorders not otherwise specified (EDNOS), thus hampering both clinical practice and research. The use of our recently proposed alternative criteria for AN would result in most children and adolescents with an AN-like phenotype receiving a diagnosis of AN. Accordingly, our proposed criteria would be readily applicable to children, adolescents and adults.
Assuntos
Desenvolvimento do Adolescente/fisiologia , Anorexia Nervosa/diagnóstico , Desenvolvimento Infantil/fisiologia , Manual Diagnóstico e Estatístico de Transtornos Mentais , Adolescente , Anorexia Nervosa/fisiopatologia , Anorexia Nervosa/psicologia , Peso Corporal , Criança , HumanosRESUMO
INTRODUCTION: Functional disorders of the villous trophoblast may result in preeclampsia through the release of endothelial activating substances. Progranulin is an anti-inflammatory, pro-angiogenic cytokine with TNF-α antagonizing activity. The trophoblastic expression of progranulin is increased during preeclampsia. The aim of the study was to investigate the impact of placental progranulin synthesis on endothelial cell activation. METHODS: Placental progranulin expression was modified by transduction of an adenoviral vector. Primary isolated human umbilical venous endothelial cells (HUVECs) were incubated with conditioned medium of first trimester placental explants. Functional studies on HUVECs included assays for proliferation, viability, cytotoxicity and analyzes of Intercellular adhesion molecule-1 (ICAM-1) and E-selectin expression. RESULTS: Placental progranulin expression was more than 10-fold higher by using an adenoviral-mediated overexpression system (Ad.PGRN) compared to control vector (Ad.CTRL) and untreated controls. Incubation of HUVECs with conditioned placental medium revealed a dose-dependent increase of cytotoxicity, reduced cell proliferation and viability and resulted in an increase of ICAM-1 and E-selectin expression. Overexpression of progranulin (Ad.PGRN) antagonized the ICAM-1 expression induced by conditioned medium. However progranulin did not influence the effects on cell proliferation, viability, cytotoxicity and E-selectin expression in HUVECs. DISCUSSION: Regulation of gene expression in human placental explants is possible by usage of an adenoviral vector system. The increase of endothelial ICAM-1 expression following the incubation with placental conditioned medium was partly reversed by overexpression of placental progranulin. It is suggested that up-regulation of the placental progranulin expression is an endogenous anti-inflammatory mechanism that partially antagonizes the endothelial cell activation during preeclampsia.
Assuntos
Células Endoteliais da Veia Umbilical Humana/metabolismo , Molécula 1 de Adesão Intercelular/metabolismo , Placenta/metabolismo , Progranulinas/metabolismo , Proliferação de Células/fisiologia , Selectina E/metabolismo , Feminino , Humanos , Gravidez , Trofoblastos/metabolismo , Regulação para CimaRESUMO
The provision of good mentors and education to medical students in their residency (PJ students) bears three essential advantages: 1) If the students feel themselves in good hands, they will co-operate effectively, thereby reducing the burden of the medical staff. 2) Contented students are potential advertisers for other interns, clinical trainees, medical students in residency and Ph.D. students. 3) Given the lack of doctors, providing students with good mentors and training is a valuable long-term strategy for the recruitment of doctors; in the event of later employment, former students in residency represent employees who are motivated, well trained, and familiar with hospital routine--a classical win-win situation.
Assuntos
Psiquiatria do Adolescente/educação , Psiquiatria Infantil/educação , Internato e Residência , Mentores , Psicoterapia/educação , Adolescente , Escolha da Profissão , Criança , Competência Clínica , Currículo , Alemanha , Humanos , Comunicação Interdisciplinar , Conselhos de Especialidade ProfissionalRESUMO
BACKGROUND: At present pathogenic mechanisms of cancer cachexia are poorly understood. Previous evidence in animal models implicates the melanocortin-4 receptor gene (MC4R) in the development of cancer cachexia. In humans, MC4R mutations that lead to an impaired receptor function are associated with obesity; in contrast, the most frequent polymorphism (Val103Ile, rs2229616; heterozygote frequency approximately 2%) was shown to be negatively associated with obesity. We tested if cancer patients that are homo-/heterozygous for the Val103Ile polymorphism are more likely to develop cachexia and/or a loss of appetite than non-carriers of the 103Ile-allele. METHODS: BMI (body mass index in kg/m2) of 509 patients (295 males) with malignant neoplasms was determined; additionally patients were asked about premorbid/pretherapeutical changes of appetite and weight loss. Cachexia was defined as a weight loss of at least 5% prior to initiation of therapy; to fulfil this criterion this weight loss had to occur independently of other plausible reasons; in single cases weight loss was the initial reason for seeing a physician. The average age in years (+/- SD) was 59.0 +/- 14.5 (males: 58.8 +/- 14.0, females 59.2 +/- 14.0). Blood samples were taken for genotyping of the Val103Ile by PCR- RFLP. RESULTS: Most of the patients suffered from lymphoma, leukaemia and gastrointestinal tumours. 107 of the patients (21%) fulfilled our criteria for cancer cachexia. We did not detect association between the Val103Ile polymorphism and cancer cachexia. However, if we exploratively excluded the patients with early leucaemic stages, we detected a trend towards the opposite effect (p < 0.05); heterozygotes for the 103Ile-allele developed cancer cachexia less frequently in comparison to the rest of the study group. Changes of appetite were not associated with the 103Ile-allele carrier status (p > 0.39). CONCLUSION: Heterozygotes for the 103Ile-allele are not more prone to develop cancer cachexia than patients without this allele; possibly, Ile103 carriers might be more resistant to cancer cachexia in patients with solid tumors. Further studies of the melanocortinergic system in cachexia of patients with solid tumors are warranted.
Assuntos
Caquexia/genética , Neoplasias/classificação , Neoplasias/complicações , Polimorfismo Genético , Receptor Tipo 4 de Melanocortina/genética , Progressão da Doença , Feminino , Neoplasias Gastrointestinais/complicações , Frequência do Gene , Heterozigoto , Humanos , Leucemia/complicações , Linfoma/complicações , Masculino , Pessoa de Meia-IdadeRESUMO
High rates of lethal outcome in tumour metastasis are associated with the acquisition of invasiveness and chemoresistance. Several clinical studies indicate that E2F1 overexpression across high-grade tumours culminates in unfavourable prognosis and chemoresistance in patients. Thus, fine-tuning the expression of E2F1 could be a promising approach for treating patients showing chemoresistance. Methods: We integrated bioinformatics, structural and kinetic modelling, and experiments to study cooperative regulation of E2F1 by microRNA (miRNA) pairs in the context of anticancer chemotherapy resistance. Results: We showed that an enhanced E2F1 repression efficiency can be achieved in chemoresistant tumour cells through two cooperating miRNAs. Sequence and structural information were used to identify potential miRNA pairs that can form tertiary structures with E2F1 mRNA. We then employed molecular dynamics simulations to show that among the identified triplexes, miR-205-5p and miR-342-3p can form the most stable triplex with E2F1 mRNA. A mathematical model simulating the E2F1 regulation by the cooperative miRNAs predicted enhanced E2F1 repression, a feature that was verified by in vitro experiments. Finally, we integrated this cooperative miRNA regulation into a more comprehensive network to account for E2F1-related chemoresistance in tumour cells. The network model simulations and experimental data indicate the ability of enhanced expression of both miR-205-5p and miR-342-3p to decrease tumour chemoresistance by cooperatively repressing E2F1. Conclusions: Our results suggest that pairs of cooperating miRNAs could be used as potential RNA therapeutics to reduce E2F1-related chemoresistance.
Assuntos
Regulação para Baixo , Resistencia a Medicamentos Antineoplásicos , Fator de Transcrição E2F1/biossíntese , MicroRNAs/metabolismo , RNA Mensageiro/metabolismo , Linhagem Celular Tumoral , Fator de Transcrição E2F1/genética , Humanos , MicroRNAs/química , Modelos Teóricos , Simulação de Dinâmica Molecular , Conformação de Ácido Nucleico , Ligação Proteica , RNA Mensageiro/químicaRESUMO
Cancer is a disease of subverted regulatory pathways. In this paper, we reconstruct the regulatory network around E2F, a family of transcription factors whose deregulation has been associated to cancer progression, chemoresistance, invasiveness, and metastasis. We integrate gene expression profiles of cancer cell lines from two E2F1-driven highly aggressive bladder and breast tumors, and use network analysis methods to identify the tumor type-specific core of the network. By combining logic-based network modeling, in vitro experimentation, and gene expression profiles from patient cohorts displaying tumor aggressiveness, we identify and experimentally validate distinctive, tumor type-specific signatures of receptor proteins associated to epithelial-mesenchymal transition in bladder and breast cancer. Our integrative network-based methodology, exemplified in the case of E2F1-induced aggressive tumors, has the potential to support the design of cohort- as well as tumor type-specific treatments and ultimately, to fight metastasis and therapy resistance.Deregulation of E2F family transcription factors is associated with cancer progression and metastasis. Here, the authors construct a map of the regulatory network around the E2F family, and using gene expression profiles, identify tumour type-specific regulatory cores and receptor expression signatures associated with epithelial-mesenchymal transition in bladder and breast cancer.
RESUMO
Chronic hepatitis B virus (HBV) infection is the major risk for hepatocellular carcinomas (HCC). HBV X protein (HBx) and p53 tumor suppressor family interactions may be crucial for HCC induction. We compared p53 and p73 interactions with HBx in normal and HCC tumor cell lines differing in their p53 status. In the latter, HBx was pro-apoptotic but exhibited opposite effects in non-tumor cells. In these normal cells, p53 and p73 were retained in the cytoplasm. In hepatoma cells, however, HBx led to nuclear translocation of p53 and p73, followed by enhanced transactivation of p53-dependent promoters. The nuclear transfer of p53, but not of p73, was abrogated by protein kinase C inhibitor Gö6976. HBx overexpression in HCC cells led to strong p53 phosphorylation at Ser15, but not in non-tumor cells. Our results define ATM kinase as mediator for HBx-induced p53 phosphorylation. While HBx promotes cell death in p53/p73-positive hepatoma cells also in presence of increased levels of the oncogenic ΔTAp73 isoform, it significantly potentiates ΔTAp73-mediated proliferation and malignant transformation of fibroblasts. Our data suggest that prevention of apoptosis in normal cells by HBx through inhibition of pro-apoptotic p53 family members via direct interaction and coaction with anti-apoptotic ΔTAp73 seems to be the key element in the decision in favor of cell survival. The complex cell context-dependent interactions between p53 family members and HBx in the regulation of apoptosis may be essential in HBV-induced HCC and anticancer therapy.
Assuntos
Apoptose/fisiologia , Carcinoma Hepatocelular/etiologia , Proteínas de Ligação a DNA/metabolismo , Vírus da Hepatite B/metabolismo , Hepatite B Crônica/complicações , Neoplasias Hepáticas/etiologia , Proteínas Nucleares/metabolismo , Transativadores/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Transporte Ativo do Núcleo Celular , Animais , Proteínas Mutadas de Ataxia Telangiectasia , Carbazóis , Carcinoma Hepatocelular/metabolismo , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Primers do DNA/genética , Citometria de Fluxo , Imunofluorescência , Hepatite B Crônica/metabolismo , Humanos , Imunoprecipitação , Neoplasias Hepáticas/metabolismo , Camundongos , Microscopia Confocal , Modelos Biológicos , Células NIH 3T3 , Fosforilação , Proteínas Serina-Treonina Quinases/metabolismo , Proteína Tumoral p73 , Proteínas Virais Reguladoras e AcessóriasRESUMO
BACKGROUND: A considerable percentage of children and adolescents who avoid school have mental illnesses. This article reviews the typical manifestations, classification, development, course, and treatment of school-avoiding behavior. METHODS: Based on a selective review of recent literature, we present findings on the psychopathologically relevant features of school-avoiding children and adolescents, including psychiatric diagnoses, developmental, family-related, and psychological test variables. The emphasis is placed on our own studies of the subject. RESULTS: Although the evidence from the studies that have been performed to date is not definitive, the available findings show that school avoidance is associated with poor mental health and with unfavorable consequences onward into adulthood. Its causes include a number of individual and social stressors that place excessive demands on the affected children and adolescents and lead them to avoid school as a coping attempt. CONCLUSIONS: Many preventive and therapeutic interventions are now available, but the existing measures need to be better coordinated, and more effort needs to be directed to the early recognition and treatment of school-avoiding behavior. Physicians should consider the possibility of mental illness. Rather than writing sick notes or prescribing mother-child treatments at health resorts, which rather tend to sustain the problem, they should refer patients promptly to a child and adolescent psychiatrist.
Assuntos
Comportamento do Adolescente/psicologia , Comportamento Infantil/psicologia , Transtornos da Personalidade , Estudantes/psicologia , Adolescente , Criança , Proteção da Criança/psicologia , Proteção da Criança/estatística & dados numéricos , Alemanha/epidemiologia , Humanos , Transtornos da Personalidade/diagnóstico , Transtornos da Personalidade/psicologia , Transtornos da Personalidade/terapia , Prevalência , Psicologia do Adolescente/tendências , Psicologia da Criança/tendências , Estudantes/estatística & dados numéricosRESUMO
The endoplasmic reticulum chaperone GRP78/BIP plays a central role in the prosurvival machinery, and its enhanced expression has been implicated in drug resistance, carcinogenesis, and metastasis. E2F1, as part of an antitumor safeguard mechanism, promotes apoptosis regardless of functional p53. Using cells that are defective in p53, we show that E2F1 represses GRP78/BIP at the transcriptional level, and this requires its DNA binding domain. Analysis of human GRP78/BIP promoter reporter constructs revealed that the region between -371 and -109 of the proximal promoter contains major E2F1-responsive elements. Toward understanding the underlying mechanism of this regulation, we performed chromatin immunoprecipitation and gel shift assays, demonstrating that E2F1 directly binds to GC-rich regions in the distal GC-box and endoplasmic reticulum stress response element -126 by interfering with the binding of positive regulatory proteins Sp1 and TFII-I of the ER stress response element-binding factor complex. We further show that TFII-I, which is required for optimal stress induction of GRP78/BIP, is suppressed by E2F1 on the protein level. Finally, our studies suggest a molecular link between the inhibition of GRP78/BIP and E2F1-mediated chemosensitization of tumor cells, underscoring its relevance for cancer treatment. Together, the data provide a new mechanism for the incompletely understood tumor suppressor function of E2F1.