RESUMO
The spatiotemporal program of metazoan DNA replication is regulated during development and altered in cancers. We have generated novel OK-seq, Repli-seq and RNA-seq data to compare the DNA replication and gene expression programs of twelve cancer and non-cancer human cell types. Changes in replication fork directionality (RFD) determined by OK-seq are widespread but more frequent within GC-poor isochores and largely disconnected from transcription changes. Cancer cell RFD profiles cluster with non-cancer cells of similar developmental origin but not with different cancer types. Importantly, recurrent RFD changes are detected in specific tumour progression pathways. Using a model for establishment and early progression of chronic myeloid leukemia (CML), we identify 1027 replication initiation zones (IZs) that progressively change efficiency during long-term expression of the BCR-ABL1 oncogene, being twice more often downregulated than upregulated. Prolonged expression of BCR-ABL1 results in targeting of new IZs and accentuation of previous efficiency changes. Targeted IZs are predominantly located in GC-poor, late replicating gene deserts and frequently silenced in late CML. Prolonged expression of BCR-ABL1 results in massive deletion of GC-poor, late replicating DNA sequences enriched in origin silencing events. We conclude that BCR-ABL1 expression progressively affects replication and stability of GC-poor, late-replicating regions during CML progression.
Assuntos
Replicação do DNA/genética , Sequência Rica em GC/genética , Perfilação da Expressão Gênica , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Origem de Replicação/genética , Linhagem Celular , Linhagem Celular Tumoral , Proteínas de Fusão bcr-abl/genética , Instabilidade Genômica , Células HeLa , Humanos , Células K562 , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologiaRESUMO
Ovarian adenocarcinoma is the gynecological malignancy with the worst prognosis and the highest mortality rate. In the first stages of treatment, chemotherapy results effective, but its prolonged use and high doses lead to the appearance of resistance to treatments and relapse in most patients, representing a major challenge for clinicians. We developed PEP-010, a cell penetrating proapoptotic peptide disrupting the protein-protein interaction between caspase-9 and protein phosphatase 2A, thereby leading to the recovery of their activity in the apoptotic pathway. MTT assay or Annexin-V/Propidium Iodide staining and flow cytometry analysis were used to assess sensitivity to chemotherapies and apoptosis after treatment with PEP-010 in monotherapy or in combination with paclitaxel in ovarian carcinoma cell lines. DNA damage was assessed by immunofluorescence using γH2AX marker. We show here that PEP-010 effectively induces cell death in monotherapy on in up to 55% of cells from ovarian adenocarcinoma cell models resistant to different chemotherapies. Moreover, when used in combination with paclitaxel, one of the therapeutic options for recurrent ovarian carcinoma, PEP-010 showed a beneficial effect leading to the reduction of the IC50 of paclitaxel of 2.2 times and to apoptosis in 87% of cells. The described results suggest the potential therapeutic interest for PEP-010 and lead to the choice of ovarian adenocarcinoma as one of the major indications of the ongoing clinical trial.
RESUMO
Metastases are the major cause of cancer-related death, yet, molecular weaknesses that could be exploited to prevent tumor cells spreading are poorly known. Here, we found that perturbing hydrolase transport to lysosomes by blocking either the expression of IGF2R, the main receptor responsible for their trafficking, or GNPT, a transferase involved in the addition of the specific tag recognized by IGF2R, reduces melanoma invasiveness potential. Mechanistically, we demonstrate that the perturbation of this traffic, leads to a compensatory lysosome neo-biogenesis devoided of degradative enzymes. This regulatory loop relies on the stimulation of TFEB transcription factor expression. Interestingly, the inhibition of this transcription factor playing a key role of lysosome production, restores melanomas' invasive potential in the absence of hydrolase transport. These data implicate that targeting hydrolase transport in melanoma could serve to develop new therapies aiming to prevent metastasis by triggering a physiological response stimulating TFEB expression in melanoma.
Assuntos
Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos , Hidrolases , Lisossomos , Melanoma , Humanos , Melanoma/genética , Melanoma/patologia , Melanoma/metabolismo , Lisossomos/metabolismo , Hidrolases/metabolismo , Hidrolases/genética , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , Linhagem Celular Tumoral , Receptor IGF Tipo 2/metabolismo , Receptor IGF Tipo 2/genética , Metástase Neoplásica , Transporte Proteico , Regulação Neoplásica da Expressão GênicaRESUMO
OBJECTIVE: For ICD-10 coding causes of death in France in 2018 and 2019, predictions by deep neural networks (DNNs) are employed in addition to fully automatic batch coding by a rule-based expert system and to interactive coding by the coding team focused on certificates with a special public health interest and those for which DNNs have a low confidence index. METHODS: Supervised seq-to-seq DNNs are trained on previously coded data to ICD-10 code multiple causes and underlying causes of death. The DNNs are then used to target death certificates to be sent to the coding team and to predict multiple causes and underlying causes of death for part of the certificates. Hence, the coding campaign for 2018 and 2019 combines three modes of coding and a loop of interaction between the three. FINDINGS: In this campaign, 62% of the certificates are automatically batch coded by the expert system, 3% by the coding team, and the remainder by DNNs. Compared to a traditional campaign that would have relied on automatic batch coding and manual coding, the present campaign reaches an accuracy of 93.4% for ICD-10 coding of the underlying cause (95.6% at the European shortlist level). Some limitations (risks of under- or overestimation) appear for certain ICD categories, with the advantage of being quantifiable. CONCLUSION: The combination of the three coding methods illustrates how artificial intelligence, automated and human codings are mutually enriching. Quantified limitations on some chapters of ICD codes encourage an increase in the volume of certificates sent for manual coding from 2021 onward.
Assuntos
Causas de Morte , Codificação Clínica , Atestado de Óbito , Classificação Internacional de Doenças , Redes Neurais de Computação , França , Humanos , Codificação Clínica/normas , Codificação Clínica/métodos , Sistemas Inteligentes , Masculino , Lactente , Feminino , Criança , Idoso , Pré-EscolarRESUMO
MCL-1, an anti-apoptotic member of the BCL-2 protein family, is overexpressed in many types of cancer and contributes to chemotherapy resistance. The drimane derivative NA1-115-7 is a natural compound isolated from Zygogynum pancheri that can be considered as a very promising lead for treating MCL-1-dependent hematological malignancies. As this drug suffers from low stability in acidic conditions and poor aqueous solubility, we evaluated the potential oral use of NA1-115-7 by encapsulating it in lipid nanoemulsions (NA-NEs) prepared by spontaneous emulsification. NA-NEs showed a particle size of 41.9 ± 2.2 nm, PDI of 0.131 ± 0.016, zeta potential of -5.8 ± 3.4 mV, encapsulation efficiency of approximately 100 % at a concentration of 24 mM. The stability of NA-1-115-7 was sixfold higher than that of the unencapsulated drug in simulated gastric fluid. NA-NEs significantly restored apoptosis and halved the effective doses of NA1-115-7 on BL2, a Burkitt lymphoma cell line, without toxicity in normal cells. Such a drug-delivery system appears to be particularly interesting for the oral administration of NA1-115-7, as it improves its solubility and stability, as well as efficacy, by reducing the therapeutic dose, making it possible to further consider in-vivo studies of this promising drug in BL2 xenografted mice.
Assuntos
Antineoplásicos , Transtornos Linfoproliferativos , Animais , Camundongos , Administração Oral , Antineoplásicos/farmacologia , Emulsões , Proteína de Sequência 1 de Leucemia de Células Mieloides , Tamanho da Partícula , NanoestruturasRESUMO
The overexpression of antiapoptotic members (BCL-2, BCL-xL, MCL-1, etc.) of the BCL-2 family contributes to tumor development and resistance to chemotherapy or radiotherapy. Synthetic inhibitors targeting these proteins have been developed, and some hematological malignancies are now widely treated with a BCL-2 inhibitor (venetoclax). However, acquired resistance to venetoclax or chemotherapy drugs due to an upregulation of MCL-1 has been observed, rendering MCL-1 an attractive new target for treatment. Six MCL-1 inhibitors (S64315, AZD-5991, AMG-176, AMG-397, ABBV-467 and PRT1419) have been evaluated in clinical trials since 2016, but some were affected by safety issues and none are currently used clinically. There is, therefore, still a need for alternative molecules. We previously described two drimane derivatives as the first covalent BH3 mimetics targeting MCL-1. Here, we described the characterization and biological efficacy of one of these compounds (NA1-115-7), isolated from Zygogynum pancheri, a plant belonging to the Winteraceae family. NA1-115-7 specifically induced the apoptosis of MCL-1-dependent tumor cells, with two hours of treatment sufficient to trigger cell death. The treatment of lymphoma cells with NA1-115-7 stabilized MCL-1, disrupted its interactions with BAK, and rapidly induced apoptosis through a BAK- and BAX-mediated process. Importantly, a similar treatment with NA1-115-7 was not toxic to erythrocytes, peripheral blood mononuclear cells, platelets, or cardiomyocytes. These results highlight the potential of natural products for use as specific BH3 mimetics non-toxic to normal cells, and they suggest that NA1-115-7 may be a promising tool for use in cancer treatment.
Assuntos
Antineoplásicos , Neoplasias Hematológicas , Antineoplásicos/farmacologia , Apoptose , Compostos Bicíclicos Heterocíclicos com Pontes , Linhagem Celular Tumoral , Neoplasias Hematológicas/tratamento farmacológico , Humanos , Leucócitos Mononucleares/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Miócitos Cardíacos/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Sulfonamidas , Winteraceae/metabolismo , Proteína Killer-Antagonista Homóloga a bcl-2/metabolismo , Proteína bcl-X/metabolismoRESUMO
Shiga toxins (Stxs), also known as Shiga-like toxins (SLT) or verotoxins (VT), constitute a family of structurally and functionally related cytotoxic proteins produced by the enteric pathogens Shigella dysenteriae type 1 and Stx-producing Escherichia coli (STEC). Infection with these bacteria causes bloody diarrhea and other pathological manifestations that can lead to HUS (hemolytic and uremic syndrome). At the cellular level, Stxs bind to the cellular receptor Gb3 and inhibit protein synthesis by removing an adenine from the 28S rRNA. This triggers multiple cellular signaling pathways, including the ribotoxic stress response (RSR), unfolded protein response (UPR), autophagy and apoptosis. Stxs cause several pathologies of major public health concern, but their specific targeting of host cells and efficient delivery to the cytosol could potentially be exploited for biomedical purposes. Moreover, high levels of expression have been reported for the Stxs receptor, Gb3/CD77, in Burkitt's lymphoma (BL) cells and on various types of solid tumors. These properties have led to many attempts to develop Stxs as tools for biomedical applications, such as cancer treatment or imaging, and several engineered Stxs are currently being tested. We provide here an overview of these studies.
Assuntos
Antineoplásicos/farmacologia , Neoplasias/tratamento farmacológico , Toxinas Shiga/farmacologia , Apoptose , Autofagia , Sistemas de Liberação de Medicamentos , Humanos , Ribossomos/efeitos dos fármacos , Toxinas Shiga/química , Transdução de Sinais/efeitos dos fármacos , Triexosilceramidas/metabolismoRESUMO
Drimane sesquiterpenoid dialdehydes are natural compounds with antiproliferative properties. Nevertheless, their mode of action has not yet been discovered. Herein, we demonstrate that various drimanes are potent inhibitors of MCL-1 and BCL-xL, two proteins of the BCL-2 family that are overexpressed in various cancers, including lymphoid malignancies. Subtle changes in their structure significantly modified their activity on the target proteins. The two most active compounds are MCL-1 selective and bind in the BH3 binding groove of the protein. Complementary studies by NMR spectroscopy and mass spectrometry analyses, but also synthesis, showed that they covalently inhibit MCL-1 though the formation of a pyrrole adduct. In addition, cytotoxic assays revealed that these two compounds show a cytotoxic selectivity for BL2, a MCL-1/BCL-xL-dependent cell line and induce apoptosis.
Assuntos
Antineoplásicos/farmacologia , Proteína de Sequência 1 de Leucemia de Células Mieloides/antagonistas & inibidores , Sesquiterpenos Policíclicos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estrutura Molecular , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Sesquiterpenos Policíclicos/síntese química , Sesquiterpenos Policíclicos/química , Domínios Proteicos/efeitos dos fármacos , Relação Estrutura-Atividade , Proteína X Associada a bcl-2/antagonistas & inibidores , Proteína X Associada a bcl-2/metabolismoRESUMO
Post-transplant lymphoproliferative disorders (PTLD) and Burkitt's lymphoma (BL) are B-cell malignancies strongly associated with Epstein-Barr virus (EBV) infection. In these lymphoproliferative disorders, EBV infection induces an increase in the expression of the anti-apoptotic protein BCL-2. Given its chemoprotective effect, BCL-2 constitutes an attractive target for new therapeutic strategies for EBV-positive B-cell malignancies. Here, we show that ABT-737, a small inhibitor of BCL-2, BCL-X(L), and BCL-w, strongly induced apoptosis in vitro in EBV-positive lymphoblastoid cell lines (which is a model for PTLD), whereas BL was less sensitive. ABT-737 reduced tumor growth and increased the overall survival of mice in a xenograft model of PTLD but had no effect on BL xenograft mice. ABT-737 combined with a low dose of cyclophosphamide, a major component of the conventional CHOP chemotherapy regimen for BL patients, reduced tumor growth during treatment but failed to improve the overall survival of BL xenograft mice. By contrast, the combination of ABT-737 and rituximab, one of the main options for the treatment of PTLD, was highly efficient and induced approximately 70% remission in PTLD xenograft mice. These results suggest that the use of agents targeting BCL-2, either alone or in combination with other conventional drugs, represents a novel promising approach for post-transplant EBV-positive B lymphoproliferative disorders.
Assuntos
Compostos de Bifenilo/farmacologia , Infecções por Vírus Epstein-Barr/tratamento farmacológico , Transtornos Linfoproliferativos/tratamento farmacológico , Transtornos Linfoproliferativos/virologia , Nitrofenóis/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Sulfonamidas/farmacologia , Transplante/efeitos adversos , Animais , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Ciclofosfamida/farmacologia , Feminino , Camundongos Endogâmicos NOD , Camundongos SCID , Piperazinas/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Rituximab/farmacologia , Resultado do Tratamento , Proteína X Associada a bcl-2/metabolismoRESUMO
Shiga toxins (Stxs) expressed by the enterohaemorrhagic Escherichia coli and enteric Shigella dysenteriae 1 pathogens are protein synthesis inhibitors. Stxs have been shown to induce apoptosis via the activation of extrinsic and intrinsic pathways in many cell types (epithelial, endothelial, and B cells) but the link between the protein synthesis inhibition and caspase activation is still unclear. Endoplasmic reticulum (ER) stress induced by the inhibition of protein synthesis may be this missing link. Here, we show that the treatment of Burkitt lymphoma (BL) cells with verotoxin-1 (VT-1 or Stx1) consistently induced the ER stress response by activation of IRE1 and ATF6-two ER stress sensors-followed by increased expression of the transcription factor C/REB homologous protein (CHOP). However, our data suggest that, although ER stress is systematically induced by VT-1 in BL cells, its role in cell death appears to be cell specific and can be the opposite: ER stress may enhance VT-1-induced apoptosis through CHOP or play a protective role through ER-phagy, depending on the cell line. Several engineered Stxs are currently under investigation as potential anti-cancer agents. Our results suggest that a better understanding of the signaling pathways induced by Stxs is needed before using them in the clinic.
Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Linfoma de Burkitt/tratamento farmacológico , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Toxina Shiga I/farmacologia , Fator 6 Ativador da Transcrição/genética , Fator 6 Ativador da Transcrição/metabolismo , Linfoma de Burkitt/genética , Linfoma de Burkitt/metabolismo , Linfoma de Burkitt/patologia , Linhagem Celular Tumoral , Endorribonucleases/genética , Endorribonucleases/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais , Fator de Transcrição CHOP/genética , Fator de Transcrição CHOP/metabolismoRESUMO
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMO
BACKGROUND: Mortality surveillance is of fundamental importance to public health surveillance. The real-time recording of death certificates, thanks to Electronic Death Registration System (EDRS), provides valuable data for reactive mortality surveillance based on medical causes of death in free-text format. Reactive mortality surveillance is based on the monitoring of mortality syndromic groups (MSGs). An MSG is a cluster of medical causes of death (pathologies, syndromes or symptoms) that meets the objectives of early detection and impact assessment of public health events. The aim of this study is to implement and measure the performance of a rule-based method and two supervised models for automatic free-text cause of death classification from death certificates in order to implement them for routine surveillance. METHOD: A rule-based method was implemented using four processing steps: standardization rules, splitting causes of death using delimiters, spelling corrections and dictionary projection. A supervised machine learning method using a linear Support Vector Machine (SVM) classifier was also implemented. Two models were produced using different features (SVM1 based solely on surface features and SVM2 combining surface features and MSGs classified by the rule-based method as feature vectors). The evaluation was conducted using an annotated subset of electronic death certificates received between 2012 and 2016. Classification performance was evaluated on seven MSGs (Influenza, Low respiratory diseases, Asphyxia/abnormal respiration, Acute respiratory disease, Sepsis, Chronic digestive diseases, and Chronic endocrine diseases). RESULTS: The rule-based method and the SVM2 model displayed a high performance with F-measures over 0.94 for all MSGs. Precision and recall were slightly higher for the rule-based method and the SVM2 model. An error-analysis shows that errors were not specific to an MSG. CONCLUSION: The high performance of the rule-based method and SVM2 model will allow us to set-up a reactive mortality surveillance system based on free-text death certificates. This surveillance will be an added-value for public health decision making.
Assuntos
Causas de Morte , Classificação/métodos , Atestado de Óbito , Doença/classificação , Vigilância em Saúde Pública/métodos , Máquina de Vetores de Suporte , Adulto , Monitoramento Epidemiológico , França , Humanos , Masculino , Aprendizado de Máquina SupervisionadoRESUMO
Timely mortality surveillance in France is based on the monitoring of electronic death certificates to provide information to health authorities. This study aims to analyze the performance of a rule-based and a supervised machine learning method to classify medical causes of death into 60 mortality syndromic groups (MSGs). Performance was first measured on a test set. Then we compared the trends of the monthly numbers of deaths classified into MSGs from 2012 to 2016 using both methods. Among the 60 MSGs, 31 achieved recall and precision over 0.95 for either one or the other method on the test set. On the whole dataset, the correlation coefficient of the monthly numbers of deaths obtained by the two methods were close to 1 for 21 of the 31 MSGs. This approach is useful for analyzing a large number of categories or when annotated resources are limited.
Assuntos
Causas de Morte , Atestado de Óbito , Aprendizado de Máquina Supervisionado , França , Recursos em Saúde , HumanosRESUMO
Therapeutic targeting of initiating oncogenes is the mainstay of precision medicine. Considerable efforts have been expended toward silencing MYC, which drives many human cancers including Burkitt lymphomas (BL). Yet, the effects of MYC silencing on standard-of-care therapies are poorly understood. Here we found that inhibition of MYC transcription renders B-lymphoblastoid cells refractory to chemotherapeutic agents. This suggested that in the context of chemotherapy, stabilization of Myc protein could be more beneficial than its inactivation. We tested this hypothesis by pharmacologically inhibiting glycogen synthase kinase 3ß (GSK-3ß), which normally targets Myc for proteasomal degradation. We discovered that chemorefractory BL cell lines responded better to doxorubicin and other anti-cancer drugs when Myc was transiently stabilized. In vivo, GSK3 inhibitors (GSK3i) enhanced doxorubicin-induced apoptosis in BL patient-derived xenografts (BL-PDX), as well as in murine MYC-driven lymphoma allografts. This enhancement was accompanied by and required deregulation of several key genes acting in the extrinsic, death-receptor-mediated apoptotic pathway. Consistent with this mechanism of action, GSK3i also facilitated lymphoma cell killing by a death ligand TRAIL and by a death receptor agonist mapatumumab. Thus, GSK3i synergizes with both standard chemotherapeutics and direct engagers of death receptors and could improve outcomes in patients with refractory lymphomas.
Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Linfoma de Células B/tratamento farmacológico , Proteínas Proto-Oncogênicas c-myc/metabolismo , Animais , Linfoma de Burkitt/tratamento farmacológico , Linfoma de Burkitt/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Doxorrubicina/farmacologia , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Glicogênio Sintase Quinase 3 beta/metabolismo , Humanos , Linfoma de Células B/metabolismo , Masculino , Camundongos , Transdução de SinaisRESUMO
The globotriaosylceramide Gb3 is a glycosphingolipid expressed on a subpopulation of germinal center B lymphocytes which has been recognized as the B cell differentiation antigen CD77. Among tumoral cell types, Gb3/CD77 is strongly expressed in Burkitt's lymphoma (BL) cells as well as other solid tumors including breast, testicular and ovarian carcinomas. One known ligand of Gb3/CD77 is Verotoxin-1 (VT-1), a Shiga toxin produced in specific E. coli strains. Previously, we have reported that in BL cells, VT-1 induces apoptosis via a caspase-dependent and mitochondria-dependent pathway. Yet, the respective roles of various apoptogenic factors remained to be deciphered. Here, this apoptotic pathway was found to require cleavage of the BID protein by caspase-8 as well as activation of two other apoptogenic proteins, BAK and BAX. Surprisingly however, t-BID, the truncated form of BID resulting from caspase-8 cleavage, played no role in the conformational changes of BAK and BAX. Rather, their activation occurred under the control of full length BID (FL-BID). Indeed, introducing a non-cleavable form of BID (BID-D59A) into BID-deficient BL cells restored BAK and BAX activation following VT-1 treatment. Still, t-BID was involved along with FL-BID in the BAK-dependent and BAX-dependent cytosolic release of CYT C and SMAC/DIABLO from the mitochondrial intermembrane space: FL-BID was found to control the homo-oligomerization of both BAK and BAX, likely contributing to the initial release of CYT C and SMAC/DIABLO, while t-BID was needed for their hetero-oligomerization and ensuing release amplification. Together, our results reveal a functional cooperation between BAK and BAX during VT-1-induced apoptosis and, unexpectedly, that activation of caspase-8 and production of t-BID were not mandatory for initiation of the cell death process.
Assuntos
Apoptose/efeitos dos fármacos , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/fisiologia , Linfoma de Burkitt/patologia , Toxinas Shiga/farmacologia , Apoptose/genética , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/química , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/genética , Linfoma de Burkitt/genética , Caspase 8/metabolismo , Células HEK293 , Humanos , Domínios Proteicos/genética , Domínios Proteicos/fisiologia , Isoformas de Proteínas/fisiologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Células Tumorais Cultivadas , Proteína Killer-Antagonista Homóloga a bcl-2/fisiologia , Proteína X Associada a bcl-2/fisiologiaRESUMO
The Epstein-Barr virus nuclear antigen leader protein (EBNA-LP) acts as a co-activator of EBNA-2, a transcriptional activator essential for Epstein-Barr virus (EBV)-induced B-cell transformation. Burkitt's lymphoma (BL) cells harboring a mutant EBV strain that lacks both the EBNA-2 gene and 3' exons of EBNA-LP express Y1Y2-truncated isoforms of EBNA-LP (tEBNA-LP) and better resist apoptosis than if infected with the wild-type virus. In such BL cells, tEBNA-LP interacts with the protein phosphatase 2A (PP2A) catalytic subunit (PP2A C), and this interaction likely plays a role in resistance to apoptosis. Here, 28 cellular and four viral proteins have been identified by mass spectrometry as further possible interactors of tEBNA-LP. Three interactions were confirmed by immunoprecipitation and Western blotting, namely with the A structural subunit of PP2A (PP2A A), the structure-specific recognition protein 1 (SSRP1, a component of the facilitate chromatin transcription (FACT) complex), and a new form of the transcription factor EC (TFEC). Thus, tEBNA-LP appears to be involved not only in cell resistance to apoptosis through its interaction with two PP2A subunits, but also in other processes where its ability to co-activate transcriptional regulators could be important.
RESUMO
Thirty analogues of natural meiogynin A, a pan-Bcl-2 inhibitor, were prepared in order to elaborate cytotoxic compounds on specific cancer cells overexpressing one or more proteins of the Bcl-2 family. The interaction of all the new analogues with Bcl-xL, Mcl-1 and Bcl-2 proteins was first evaluated by fluorescence polarization assay (FPA) and showed that modulation of the lateral chain has a dramatic impact as subtle changes significantly modify the activity on the target proteins. The acetoxymethyl prodrugs of the two most active compounds were then elaborated to determine their cytotoxicity on B cell lines. A strong cytotoxic effect on BL2, RS4;11 and H929â¯cells was observed with a triazole prodrug that induces apoptosis.
Assuntos
Proteína de Sequência 1 de Leucemia de Células Mieloides/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Sesquiterpenos/química , Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose/antagonistas & inibidores , Linfócitos B/efeitos dos fármacos , Linhagem Celular Tumoral , Imunoensaio de Fluorescência por Polarização , Humanos , Pró-Fármacos/química , Pró-Fármacos/farmacologia , Relação Estrutura-Atividade , Proteína bcl-XRESUMO
This paper reports on Task 2 of the 2016 CLEF eHealth evaluation lab which extended the previous information extraction tasks of ShARe/CLEF eHealth evaluation labs. The task continued with named entity recognition and normalization in French narratives, as offered in CLEF eHealth 2015. Named entity recognition involved ten types of entities including disorders that were defined according to Semantic Groups in the Unified Medical Language System® (UMLS®), which was also used for normalizing the entities. In addition, we introduced a large-scale classification task in French death certificates, which consisted of extracting causes of death as coded in the International Classification of Diseases, tenth revision (ICD10). Participant systems were evaluated against a blind reference standard of 832 titles of scientific articles indexed in MEDLINE, 4 drug monographs published by the European Medicines Agency (EMEA) and 27,850 death certificates using Precision, Recall and F-measure. In total, seven teams participated, including five in the entity recognition and normalization task, and five in the death certificate coding task. Three teams submitted their systems to our newly offered reproducibility track. For entity recognition, the highest performance was achieved on the EMEA corpus, with an overall F-measure of 0.702 for plain entities recognition and 0.529 for normalized entity recognition. For entity normalization, the highest performance was achieved on the MEDLINE corpus, with an overall F-measure of 0.552. For death certificate coding, the highest performance was 0.848 F-measure.
RESUMO
The Epstein-Barr virus (EBV) is associated with various lymphoproliferative disorders and lymphomas. We have previously demonstrated that treating wild-type TP53-expressing B cell lines with the TP53 pathway activator nutlin-3 induced apoptosis in EBV-negative and EBV-positive latency I cells whereas EBV-positive latency III cells remained much more apoptosis-resistant. Here, we report a constitutively high level of autophagy in these resistant cells which express high levels of the proautophagic protein BECN1/Beclin 1 based, at least in part, on the activation of the NFKB signaling pathway by the viral protein LMP1. Following treatment with nutlin-3, several autophagy-stimulating genes were upregulated both in EBV-negative and EBV-positive latency III cells. However the process of autophagy was only triggered in the latter and was associated with an upregulation of SESN1/sestrin 1 and inhibition of MTOR more rapid than in EBV-negative cells. A treatment with chloroquine, an inhibitor of autophagy, potentiated the apoptotic effect of nutlin-3, particularly in those EBV-positive cells which were resistant to apoptosis induced by nutlin-3 alone, thereby showing that autophagy participates in this resistant phenotype. Finally, using immunohistochemical staining, clinical samples from various B cell lymphoproliferations with the EBV-positive latency II or III phenotype were found to harbor a constitutively active autophagy.