RESUMO
HSP90 is critical for maintenance of the cellular proteostasis. In cancer cells, HSP90 also becomes a nucleating site for the stabilization of multiprotein complexes including signaling pathways and transcription complexes. Here we described the role of this HSP90 form, referred to as oncogenic HSP90, in the regulation of cytosolic metabolic pathways in proliferating B-cell lymphoma cells. Oncogenic HSP90 assisted in the organization of metabolic enzymes into non-membrane-bound functional compartments. Under experimental conditions that conserved cellular proteostasis, oncogenic HSP90 coordinated and sustained multiple metabolic pathways required for energy production and maintenance of cellular biomass as well as for secretion of extracellular metabolites. Conversely, inhibition of oncogenic HSP90, in absence of apparent client protein degradation, decreased the efficiency of MYC-driven metabolic reprogramming. This study reveals that oncogenic HSP90 supports metabolism in B-cell lymphoma cells and patients with diffuse large B-cell lymphoma, providing a novel mechanism of activity for HSP90 inhibitors. SIGNIFICANCE: The oncogenic form of HSP90 organizes and maintains functional multienzymatic metabolic hubs in cancer cells, suggesting the potential of repurposing oncogenic HSP90 selective inhibitors to disrupt metabolism in lymphoma cells.
Assuntos
Carcinogênese/patologia , Proteínas de Choque Térmico HSP90/metabolismo , Linfoma Difuso de Grandes Células B/metabolismo , Linfoma Difuso de Grandes Células B/patologia , Metaboloma , Proteólise , Proteínas Proto-Oncogênicas c-myc/metabolismo , Animais , Carcinogênese/metabolismo , Estudos de Casos e Controles , Proteínas de Choque Térmico HSP90/genética , Humanos , Linfoma Difuso de Grandes Células B/genética , Camundongos , Domínios e Motivos de Interação entre Proteínas , Proteínas Proto-Oncogênicas c-myc/genética , Transdução de Sinais , Células Tumorais CultivadasRESUMO
Monoclonal antibodies that block the programmed cell death 1 (PD-1) checkpoint have revolutionized cancer immunotherapy. However, many major tumor types remain unresponsive to anti-PD-1 therapy, and even among responsive tumor types, most of the patients do not develop durable antitumor immunity. It has been shown that bispecific antibodies activate T cells by cross-linking the TCR/CD3 complex with a tumor-specific antigen (TSA). The class of TSAxCD3 bispecific antibodies have generated exciting results in early clinical trials. We have recently described another class of "costimulatory bispecifics" that cross-link a TSA to CD28 (TSAxCD28) and cooperate with TSAxCD3 bispecifics. Here, we demonstrate that these TSAxCD28 bispecifics (one specific for prostate cancer and the other for epithelial tumors) can also synergize with the broader anti-PD-1 approach and endow responsiveness-as well as long-term immune memory-against tumors that otherwise do not respond to anti-PD-1 alone. Unlike CD28 superagonists, which broadly activate T cells and induce cytokine storm, TSAxCD28 bispecifics display little or no toxicity when used alone or in combination with a PD-1 blocker in genetically humanized immunocompetent mouse models or in primates and thus may provide a well-tolerated and "off the shelf" combination approach with PD-1 immunotherapy that can markedly enhance antitumor efficacy.
Assuntos
Anticorpos Biespecíficos , Neoplasias , Animais , Anticorpos Biespecíficos/uso terapêutico , Antígenos CD28 , Humanos , Imunoterapia , Camundongos , Neoplasias/tratamento farmacológico , Receptor de Morte Celular Programada 1RESUMO
Several lines of evidence link the canonical oncogene BCL6 to stress response. Here we demonstrate that BCL6 evolved in vertebrates as a component of the HSF1-driven stress response, which has been co-opted by the immune system to support germinal center formation and may have been decisive in the convergent evolution of humoral immunity in jawless and jawed vertebrates. We find that the highly conserved BTB corepressor binding site of BCL6 mediates stress adaptation across vertebrates. We demonstrate that pan-cancer cells hijack this stress tolerance mechanism to aberrantly express BCL6. Targeting the BCL6 BTB domain in cancer cells induces apoptosis and increases susceptibility to repeated doses of cytotoxic therapy. The chemosensitization effect upon BCL6 BTB inhibition is dependent on the derepression of TOX, implicating modulation of DNA repair as a downstream mechanism. Collectively, these data suggest a form of adaptive nononcogene addiction rooted in the natural selection of BCL6 during vertebrate evolution. SIGNIFICANCE: We demonstrate that HSF1 drives BCL6 expression to enable stress tolerance in vertebrates. We identify an HSF1-BCL6-TOX stress axis that is required by cancer cells to tolerate exposure to cytotoxic agents and points toward BCL6-targeted therapy as a way to more effectively kill a wide variety of solid tumors.This article is highlighted in the In This Issue feature, p. 565.
Assuntos
Adaptação Fisiológica/fisiologia , Neoplasias/tratamento farmacológico , Proteínas Proto-Oncogênicas c-bcl-6/metabolismo , Estresse Fisiológico/fisiologia , Animais , Apoptose/fisiologia , Linfócitos B/citologia , Linfócitos B/fisiologia , Proliferação de Células/fisiologia , Células Cultivadas , Feminino , Centro Germinativo/citologia , Centro Germinativo/fisiologia , Fatores de Transcrição de Choque Térmico/biossíntese , Fatores de Transcrição de Choque Térmico/genética , Fatores de Transcrição de Choque Térmico/metabolismo , Resposta ao Choque Térmico , Xenoenxertos , Humanos , Masculino , Camundongos , Camundongos Knockout , Camundongos SCID , Neoplasias/enzimologia , Neoplasias/patologia , Proteínas Proto-Oncogênicas c-bcl-6/genéticaRESUMO
Although the BCL6 transcriptional repressor is frequently expressed in human follicular lymphomas (FL), its biological role in this disease remains unknown. Herein, we comprehensively identify the set of gene promoters directly targeted by BCL6 in primary human FLs. We noted that BCL6 binds and represses NOTCH2 and NOTCH pathway genes. Moreover, BCL6 and NOTCH2 pathway gene expression is inversely correlated in FL. Notably, BCL6 upregulation is associated with repression of NOTCH2 and its target genes in primary human and murine germinal center (GC) cells. Repression of NOTCH2 is an essential function of BCL6 in FL and GC B cells because inducible expression of Notch2 abrogated GC formation in mice and killed FL cells. Indeed, BCL6-targeting compounds or gene silencing leads to the induction of NOTCH2 activity and compromises survival of FL cells, whereas NOTCH2 depletion or pathway antagonists rescue FL cells from such effects. Moreover, BCL6 inhibitors induced NOTCH2 expression and suppressed growth of human FL xenografts in vivo and primary human FL specimens ex vivo These studies suggest that established FLs are thus dependent on BCL6 through its suppression of NOTCH2Significance: We show that human FLs are dependent on BCL6, and primary human FLs can be killed using specific BCL6 inhibitors. Integrative genomics and functional studies of BCL6 in primary FL cells point toward a novel mechanism whereby BCL6 repression of NOTCH2 drives the survival and growth of FL cells as well as GC B cells, which are the FL cell of origin. Cancer Discov; 7(5); 506-21. ©2017 AACR.This article is highlighted in the In This Issue feature, p. 443.
Assuntos
Linfoma Folicular/patologia , Proteínas Proto-Oncogênicas c-bcl-6/metabolismo , Receptor Notch2/metabolismo , Animais , Linfócitos B/metabolismo , Regulação Neoplásica da Expressão Gênica/fisiologia , Centro Germinativo/metabolismo , Xenoenxertos , Humanos , Linfoma Folicular/metabolismo , Camundongos , Camundongos SCIDRESUMO
Peripheral T-cell lymphomas (PTCL) are aggressive diseases with poor response to chemotherapy and dismal survival. Identification of effective strategies to target PTCL biology represents an urgent need. Here we report that PTCL are sensitive to transcription-targeting drugs, and, in particular, to THZ1, a covalent inhibitor of cyclin-dependent kinase 7 (CDK7). The STAT-signalling pathway is highly vulnerable to THZ1 even in PTCL cells that carry the activating STAT3 mutation Y640F. In mutant cells, CDK7 inhibition decreases STAT3 chromatin binding and expression of highly transcribed target genes like MYC, PIM1, MCL1, CD30, IL2RA, CDC25A and IL4R. In surviving cells, THZ1 decreases the expression of STAT-regulated anti-apoptotic BH3 family members MCL1 and BCL-XL sensitizing PTCL cells to BH3 mimetic drugs. Accordingly, the combination of THZ1 and the BH3 mimetic obatoclax improves lymphoma growth control in a primary PTCL ex vivo culture and in two STAT3-mutant PTCL xenografts, delineating a potential targeted agent-based therapeutic option for these patients.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Quinases Ciclina-Dependentes/metabolismo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Linfoma de Células T/tratamento farmacológico , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Apoptose/efeitos dos fármacos , Apoptose/genética , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Cromatina/metabolismo , Quinases Ciclina-Dependentes/antagonistas & inibidores , Feminino , Mutação com Ganho de Função , Humanos , Indóis , Linfoma de Células T/genética , Linfoma de Células T/patologia , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Fenilenodiaminas/farmacologia , Fenilenodiaminas/uso terapêutico , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Pirimidinas/farmacologia , Pirimidinas/uso terapêutico , Pirróis/farmacologia , Pirróis/uso terapêutico , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Transcrição Gênica/efeitos dos fármacos , Resultado do Tratamento , Ensaios Antitumorais Modelo de Xenoenxerto , Quinase Ativadora de Quinase Dependente de CiclinaRESUMO
Anaplastic large cell lymphomas (ALCL) represent a peripheral T-cell lymphoma subgroup, stratified based on the presence or absence of anaplastic lymphoma kinase (ALK) chimeras. Although ALK-positive ALCLs have a more favorable outcome than ALK-negative ALCL, refractory and/or relapsed forms are common and novel treatments are needed. Here we investigated the therapeutic potential of a novel bromodomain inhibitor, OTX015/MK-8628 in ALK-positive ALCLs.The effects of OTX015 on a panel of ALK+ ALCL cell lines was evaluated in terms of proliferation, cell cycle and downstream signaling, including gene expression profiling analyses. Synergy was tested with combination targeted therapies.Bromodomain inhibition with OTX015 led primarily to ALCL cell cycle arrest in a dose-dependent manner, along with downregulation of MYC and its downstream regulated genes. MYC overexpression did not compensate this OTX015-mediated phenotype. Transcriptomic analysis of OTX015-treated ALCL cells identified a gene signature common to various hematologic malignancies treated with bromodomain inhibitors, notably large cell lymphoma. OTX015-modulated genes included transcription factors (E2F2, NFKBIZ, FOS, JUNB, ID1, HOXA5 and HOXC6), members of multiple signaling pathways (ITK, PRKCH, and MKNK2), and histones (clusters 1-3). Combination of OTX015 with the Bruton's tyrosine kinase (BTK) inhibitor ibrutinib led to cell cycle arrest then cell death, and combination with suboptimal doses of the ALK inhibitor CEP28122 caused cell cycle arrest. When OTX015 was associated with GANT61, a selective GLI1/2 inhibitor, C1156Y-resistant ALK ALCL growth was impaired.These findings support OTX015 clinical trials in refractory ALCL in combination with inhibitors of interleukin-2-inducible kinase or SHH/GLI1.
Assuntos
Acetanilidas/farmacologia , Antineoplásicos/farmacologia , Biomarcadores Tumorais/genética , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Compostos Heterocíclicos com 3 Anéis/farmacologia , Linfoma Anaplásico de Células Grandes/tratamento farmacológico , Receptores Proteína Tirosina Quinases/genética , Quinase do Linfoma Anaplásico , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Perfilação da Expressão Gênica/métodos , Regulação Neoplásica da Expressão Gênica , Predisposição Genética para Doença , Humanos , Concentração Inibidora 50 , Linfoma Anaplásico de Células Grandes/genética , Linfoma Anaplásico de Células Grandes/patologia , Fenótipo , Transdução de Sinais/efeitos dos fármacos , Fatores de Tempo , TranscriptomaRESUMO
Diffuse large B cell lymphomas (DLBCLs) arise from proliferating B cells transiting different stages of the germinal center reaction. In activated B cell DLBCLs (ABC-DLBCLs), a class of DLBCLs that respond poorly to current therapies, chromosomal translocations and amplification lead to constitutive expression of the B cell lymphoma 6 (BCL6) oncogene. The role of BCL6 in maintaining these lymphomas has not been investigated. Here, we designed small-molecule inhibitors that display higher affinity for BCL6 than its endogenous corepressor ligands to evaluate their therapeutic efficacy for targeting ABC-DLBCL. We used an in silico drug design functional-group mapping approach called SILCS to create a specific BCL6 inhibitor called FX1 that has 10-fold greater potency than endogenous corepressors and binds an essential region of the BCL6 lateral groove. FX1 disrupted formation of the BCL6 repression complex, reactivated BCL6 target genes, and mimicked the phenotype of mice engineered to express BCL6 with corepressor binding site mutations. Low doses of FX1 induced regression of established tumors in mice bearing DLBCL xenografts. Furthermore, FX1 suppressed ABC-DLBCL cells in vitro and in vivo, as well as primary human ABC-DLBCL specimens ex vivo. These findings indicate that ABC-DLBCL is a BCL6-dependent disease that can be targeted by rationally designed inhibitors that exceed the binding affinity of natural BCL6 ligands.
Assuntos
Antineoplásicos/farmacologia , Desenho de Fármacos , Regulação Neoplásica da Expressão Gênica , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Proteínas Proto-Oncogênicas c-bcl-6/antagonistas & inibidores , Animais , Linhagem Celular Tumoral , Doxorrubicina/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Células HEK293 , Humanos , Indóis/farmacologia , Ligantes , Linfoma Difuso de Grandes Células B/patologia , Espectroscopia de Ressonância Magnética , Masculino , Camundongos , Camundongos SCID , Transplante de Neoplasias , Ligação Proteica , Proteínas Proto-Oncogênicas c-bcl-6/metabolismo , Tiazolidinedionas/farmacologia , Translocação GenéticaRESUMO
BACKGROUND: Refractory and/or relapsed diffuse large B cell lymphoma (RR-DLBCL) patients are incurable with conventional chemotherapy due to the aggressiveness and the chemorefractory state of these tumors. DNA hypermethylation and histone deacetylation are two major epigenetic modifications by which aggressive DLBCL maintain their oncogenic state. We have previously reported that DNA methyltransferase inhibitors (DNMTI) affect RR-DLBCL growth and improve chemosensitivity. Here, we hypothesized that the combination of DNMTI with histone deacetylase inhibitor (HDI) would be an active and feasible therapeutic strategy in RR-DLBCL. Thus, we evaluated the anti-lymphoma activity of the HDI vorinostat (VST) in combination with the DNMTI azacitidine (AZA) or decitabine (DAC) in pre-clinical models of RR-DLBCL, and we determined the feasibility of the combination by conducting a phase Ib trial in RR-DLBCL patients. RESULTS: Concurrent combination of DNMTI and HDI resulted in synergistic anti-lymphoma effect toward RR-DLBCL cells in vitro and in vivo, with no significant toxicity increase. In a phase Ib trial, a total of 18 patients with a median of three prior therapies were treated with four different dose levels of AZA and VST. The most common toxicities were hematological, followed by gastrointestinal and metabolic. The clinical benefit was low as only one subject had a partial response and three subjects had stable disease. Interestingly, two of the seven patients that received additional chemotherapy post-study achieved a complete response and three others had a significant clinical benefit. These observations suggested that the combination might have a delayed chemosensitization effect that we were able to confirm by using in vitro and in vivo models. These studies also demonstrated that the addition of VST does not improve the chemosensitizing effect of DAC alone. CONCLUSIONS: Our data supports the strategy of epigenetic priming by employing DNMTI in RR-DLBCL patients in order to overcome resistance and improve their outcomes.
Assuntos
Antineoplásicos/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Inibidores de Histona Desacetilases/administração & dosagem , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Azacitidina/administração & dosagem , Azacitidina/análogos & derivados , Azacitidina/farmacologia , Linhagem Celular Tumoral , Metilação de DNA/efeitos dos fármacos , Decitabina , Epigênese Genética/efeitos dos fármacos , Feminino , Inibidores de Histona Desacetilases/farmacologia , Humanos , Ácidos Hidroxâmicos/administração & dosagem , Ácidos Hidroxâmicos/farmacologia , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , VorinostatRESUMO
The BCL6 oncogene plays a crucial role in sustaining diffuse large B-cell lymphomas (DLBCL) through transcriptional repression of key checkpoint genes. BCL6-targeted therapy kills lymphoma cells by releasing these checkpoints. However BCL6 also directly represses several DLBCL oncogenes such as BCL2 and BCL-XL that promote lymphoma survival. Herein we show that DLBCL cells that survive BCL6-targeted therapy induce a phenomenon of "oncogene-addiction switching" by reactivating BCL2-family dependent anti-apoptotic pathways. Thus, most DLBCL cells require concomitant inhibition of BCL6 and BCL2-family members for effective lymphoma killing. Moreover, in DLBCL cells initially resistant to BH3 mimetic drugs, BCL6 inhibition induces a newly developed reliance on anti-apoptotic BCL2-family members for survival that translates in acquired susceptibility to BH3 mimetic drugs ABT-737 and obatoclax. In germinal center B cell-like (GCB)-DLBCL cells, the proteasome inhibitor bortezomib and the NEDD inhibitor MLN4924 post-transcriptionally activated the BH3-only sensitizer NOXA thus counteracting the oncogenic switch to BCL2 induced by BCL6-targeting. Hence our study indicates that BCL6 inhibition induces an on-target feedback mechanism based on the activation of anti-apoptotic BH3 members. This oncogene-addition switching mechanism was harnessed to develop rational combinatorial therapies for GCB-DLBCL.
Assuntos
Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteínas Proto-Oncogênicas c-bcl-6/antagonistas & inibidores , Animais , Compostos de Bifenilo/farmacologia , Western Blotting , Proliferação de Células/efeitos dos fármacos , Humanos , Indóis , Linfoma Difuso de Grandes Células B/enzimologia , Linfoma Difuso de Grandes Células B/patologia , Masculino , Camundongos , Camundongos Nus , Nitrofenóis/farmacologia , Fragmentos de Peptídeos/farmacologia , Piperazinas/farmacologia , Proteínas Proto-Oncogênicas/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-bcl-6/genética , Proteínas Proto-Oncogênicas c-bcl-6/metabolismo , Pirróis/farmacologia , RNA Interferente Pequeno/genética , Ratos , Ratos Sprague-Dawley , Sulfonamidas/farmacologia , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Rationally designed combinations of targeted therapies for refractory cancers, such as activated B cell-like diffuse large B cell lymphoma (ABC DLBCL), are likely required to achieve potent, durable responses. Here, we used a pharmacoproteomics approach to map the interactome of a tumor-enriched isoform of HSP90 (teHSP90). Specifically, we chemically precipitated teHSP90-client complexes from DLBCL cell lines with the small molecule PU-H71 and found that components of the proximal B cell receptor (BCR) signalosome were enriched within teHSP90 complexes. Functional assays revealed that teHSP90 facilitates BCR signaling dynamics by enabling phosphorylation of key BCR signalosome components, including the kinases SYK and BTK. Consequently, treatment of BCR-dependent ABC DLBCL cells with PU-H71 attenuated BCR signaling, calcium flux, and NF-κB signaling, ultimately leading to growth arrest. Combined exposure of ABC DLBCL cell lines to PU-H71 and ibrutinib, a BCR pathway inhibitor, more potently suppressed BCR signaling than either drug alone. Correspondingly, PU-H71 combined with ibrutinib induced synergistic killing of lymphoma cell lines, primary human lymphoma specimens ex vivo, and lymphoma xenografts in vivo, without notable toxicity. Together, our results demonstrate that a pharmacoproteome-driven rational combination therapy has potential to provide more potent BCR-directed therapy for ABC DLCBL patients.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Transdução de Sinais/efeitos dos fármacos , Adenina/análogos & derivados , Tirosina Quinase da Agamaglobulinemia , Benzodioxóis/farmacologia , Linhagem Celular Tumoral , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Linfoma Difuso de Grandes Células B/metabolismo , Linfoma Difuso de Grandes Células B/patologia , Piperidinas , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/metabolismo , Proteômica , Purinas/farmacologia , Pirazóis/farmacologia , Pirimidinas/farmacologia , Receptores de Antígenos de Linfócitos B/metabolismo , Quinase SykRESUMO
Non-Hodgkin lymphomas are a heterogeneous group of lymphoproliferative disorders of B and T cell origin that are treated with chemotherapy drugs with variable success rate that has virtually not changed over decades. Although new classes of chemotherapy-free epigenetic and metabolic drugs have emerged, durable responses to these conventional and new therapies are achieved in a fraction of cancer patients, with many individuals experiencing resistance to the drugs. The paucity in our understanding of what regulates the drug resistance phenotype and establishing a predictive indicator is, in great part, due to the lack of adequate ex vivo lymphoma models to accurately study the effect of microenvironmental cues in which malignant B and T cell lymphoma cells arise and reside. Unlike many other tumors, lymphomas have been neglected from biomaterials-based microenvironment engineering standpoint. In this study, we demonstrate that B and T cell lymphomas have different pro-survival integrin signaling requirements (αvß3 and α4ß1) and the presence of supporting follicular dendritic cells are critical for enhanced proliferation in three-dimensional (3D) microenvironments. We engineered adaptable 3D tumor organoids presenting adhesive peptides with distinct integrin specificities to B and T cell lymphoma cells that resulted in enhanced proliferation, clustering, and drug resistance to the chemotherapeutics and a new class of histone deacetylase inhibitor (HDACi), Panobinostat. In Diffuse Large B cell Lymphomas, the 3D microenvironment upregulated the expression level of B cell receptor (BCR), which supported the survival of B cell lymphomas through a tyrosine kinase Syk in the upstream BCR pathway. Our integrin specific ligand functionalized 3D organoids mimic a lymphoid neoplasm-like heterogeneous microenvironment that could, in the long term, change the understanding of the initiation and progression of hematological tumors, allow primary biospecimen analysis, provide prognostic values, and importantly, allow a faster and more rational screening and translation of therapeutic regimens.
Assuntos
Hidrogéis/química , Integrinas/metabolismo , Linfoma de Células B/metabolismo , Linfoma não Hodgkin/metabolismo , Linfoma de Células T/metabolismo , Antineoplásicos/uso terapêutico , Apoptose , Materiais Biocompatíveis/química , Proliferação de Células , Técnicas de Cocultura , Células Dendríticas/citologia , Inibidores de Histona Desacetilases/química , Humanos , Ácidos Hidroxâmicos/química , Indóis/química , Integrina alfa4beta1/metabolismo , Integrina alfaVbeta3/metabolismo , Ligantes , Microscopia Confocal , Microscopia de Fluorescência , Organoides/química , Tonsila Palatina/metabolismo , Panobinostat , Receptores de Antígenos de Linfócitos B/química , Transdução de Sinais , Engenharia Tecidual/métodos , Regulação para CimaRESUMO
The interaction of lymphoid tumor cells with components of the extracellular matrix via integrin αvß3 allows tumor survival and growth. This integrin was demonstrated to be the membrane receptor for thyroid hormones (THs) in several tissues. We found that THs, acting as soluble integrin αvß3 ligands, activated growth-related signaling pathways in T-cell lymphomas (TCLs). Specifically, TH-activated αvß3 integrin signaling promoted TCL proliferation and angiogenesis, in part, via the upregulation of vascular endothelial growth factor (VEGF). Consequently, genetic or pharmacologic inhibition of integrin αvß3 decreased VEGF production and induced TCL cell death in vitro and in human xenograft models. In sum, we show that integrin αvß3 transduces prosurvival signals into TCL nuclei, suggesting a novel mechanism for the endocrine modulation of TCL pathophysiology. Targeting this mechanism could constitute an effective and potentially low-toxicity chemotherapy-free treatment of TCL patients.
Assuntos
Regulação Neoplásica da Expressão Gênica , Integrina alfaVbeta3/genética , Linfoma de Células T/genética , Linfócitos T/imunologia , Hormônios Tireóideos/genética , Animais , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Feminino , Humanos , Integrina alfaVbeta3/antagonistas & inibidores , Integrina alfaVbeta3/imunologia , Células Jurkat , Linfoma de Células T/imunologia , Linfoma de Células T/patologia , Masculino , Camundongos , Camundongos SCID , Transplante de Neoplasias , Neovascularização Patológica , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transdução de Sinais , Venenos de Serpentes/farmacologia , Linfócitos T/patologia , Hormônios Tireóideos/imunologia , Células Tumorais Cultivadas , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/imunologiaRESUMO
The EZH2 histone methyltransferase is highly expressed in germinal center (GC) B cells and targeted by somatic mutations in B cell lymphomas. Here, we find that EZH2 deletion or pharmacologic inhibition suppresses GC formation and functions. EZH2 represses proliferation checkpoint genes and helps establish bivalent chromatin domains at key regulatory loci to transiently suppress GC B cell differentiation. Somatic mutations reinforce these physiological effects through enhanced silencing of EZH2 targets. Conditional expression of mutant EZH2 in mice induces GC hyperplasia and accelerated lymphomagenesis in cooperation with BCL2. GC B cell (GCB)-type diffuse large B cell lymphomas (DLBCLs) are mostly addicted to EZH2 but not the more differentiated activated B cell (ABC)-type DLBCLs, thus clarifying the therapeutic scope of EZH2 targeting.
Assuntos
Linfócitos B/metabolismo , Transformação Celular Neoplásica/genética , Centro Germinativo/metabolismo , Mutação , Complexo Repressor Polycomb 2/fisiologia , Animais , Diferenciação Celular , Proliferação de Células , Proteína Potenciadora do Homólogo 2 de Zeste , Deleção de Genes , Regulação Neoplásica da Expressão Gênica , Centro Germinativo/efeitos dos fármacos , Histonas/metabolismo , Metilação , Camundongos , Complexo Repressor Polycomb 2/genética , Complexo Repressor Polycomb 2/metabolismo , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/fisiologiaRESUMO
Pericytes and vascular smooth muscle cells (VSMCs), which are recruited to developing blood vessels by platelet-derived growth factor BB, support endothelial cell survival and vascular stability. Here, we report that imatinib, a tyrosine kinase inhibitor of platelet-derived growth factor receptor ß (PDGFRß), impaired growth of lymphoma in both human xenograft and murine allograft models. Lymphoma cells themselves neither expressed PDGFRß nor were growth inhibited by imatinib. Tumor growth inhibition was associated with decreased microvascular density and increased vascular leakage. In vivo, imatinib induced apoptosis of tumor-associated PDGFRß(+) pericytes and loss of perivascular integrity. In vitro, imatinib inhibited PDGFRß(+) VSMC proliferation and PDGF-BB signaling, whereas small interfering RNA knockdown of PDGFRß in pericytes protected them against imatinib-mediated growth inhibition. Fluorescence-activated cell sorter analysis of tumor tissue revealed depletion of pericytes, endothelial cells, and their progenitors following imatinib treatment. Compared with imatinib, treatment with an anti-PDGFRß monoclonal antibody partially inhibited lymphoma growth. Last, microarray analysis (Gene Expression Omnibus database accession number GSE30752) of PDGFRß(+) VSMCs following imatinib treatment showed down-regulation of genes implicated in vascular cell proliferation, survival, and assembly, including those representing multiple pathways downstream of PDGFRß. Taken together, these data indicate that PDGFRß(+) pericytes may represent a novel, nonendothelial, antiangiogenic target for lymphoma therapy.
Assuntos
Inibidores da Angiogênese/farmacologia , Anticorpos Monoclonais/farmacologia , Benzamidas/farmacologia , Linfoma Difuso de Grandes Células B/prevenção & controle , Linfoma de Células T/prevenção & controle , Neovascularização Patológica/prevenção & controle , Pericitos/efeitos dos fármacos , Piperazinas/farmacologia , Pirimidinas/farmacologia , Animais , Apoptose , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Western Blotting , Diferenciação Celular , Proliferação de Células , Perfilação da Expressão Gênica , Humanos , Mesilato de Imatinib , Técnicas Imunoenzimáticas , Linfoma Difuso de Grandes Células B/metabolismo , Linfoma Difuso de Grandes Células B/patologia , Linfoma de Células T/metabolismo , Linfoma de Células T/patologia , Camundongos , Camundongos SCID , Análise de Sequência com Séries de Oligonucleotídeos , Pericitos/imunologia , Pericitos/patologia , Fator de Crescimento Derivado de Plaquetas/metabolismo , RNA Mensageiro/genética , RNA Interferente Pequeno/genética , Reação em Cadeia da Polimerase em Tempo Real , Receptor beta de Fator de Crescimento Derivado de Plaquetas/antagonistas & inibidores , Receptor beta de Fator de Crescimento Derivado de Plaquetas/genética , Receptor beta de Fator de Crescimento Derivado de Plaquetas/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Células Tumorais CultivadasRESUMO
MALT1 cleavage activity is linked to the pathogenesis of activated B cell-like diffuse large B cell lymphoma (ABC-DLBCL), a chemoresistant form of DLBCL. We developed a MALT1 activity assay and identified chemically diverse MALT1 inhibitors. A selected lead compound, MI-2, featured direct binding to MALT1 and suppression of its protease function. MI-2 concentrated within human ABC-DLBCL cells and irreversibly inhibited cleavage of MALT1 substrates. This was accompanied by NF-κB reporter activity suppression, c-REL nuclear localization inhibition, and NF-κB target gene downregulation. Most notably, MI-2 was nontoxic to mice, and displayed selective activity against ABC-DLBCL cell lines in vitro and xenotransplanted ABC-DLBCL tumors in vivo. The compound was also effective against primary human non-germinal center B cell-like DLBCLs ex vivo.
Assuntos
Linfócitos B/efeitos dos fármacos , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Proteínas de Neoplasias/antagonistas & inibidores , Inibidores de Proteases/farmacologia , Animais , Linfócitos B/metabolismo , Caspases/metabolismo , Catálise , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proteínas de Ligação a DNA/antagonistas & inibidores , Proteínas de Ligação a DNA/metabolismo , Regulação para Baixo/efeitos dos fármacos , Humanos , Linfoma Difuso de Grandes Células B/metabolismo , Linfoma Difuso de Grandes Células B/patologia , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Proteína de Translocação 1 do Linfoma de Tecido Linfoide Associado à Mucosa , NF-kappa B/metabolismo , Proteínas de Neoplasias/metabolismo , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/metabolismo , Proteólise , Proteínas Proto-Oncogênicas c-rel , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
ALK positive diffuse large B-cell lymphomas (DLBCL) are a distinct lymphoma subtype associated with a poor outcome. Most of them feature a t(2;17) encoding a clathrin (CLTC)-ALK fusion protein. The contribution of deregulated ALK-activity in the pathogenesis and maintenance of these DLBCLs is not yet known. We established and characterized the first CLTC-ALK positive DLBCL cell line (LM1). LM1 formed tumors in NOD-SCID mice. The selective ALK inhibitor NVP-TAE684 inhibited growth of LM1 cells in vitro at nanomolar concentrations. NVP-TAE684 repressed ALK-activated signalling pathways and induced apoptosis of LM1 DLBCL cells. Inhibition of ALK-activity resulted in sustained tumor regression in the xenotransplant tumor model. These data indicate a role of CLTC-ALK in the maintenance of the malignant phenotype thereby providing a rationale therapeutic target for these otherwise refractory tumors.
Assuntos
Linfoma Difuso de Grandes Células B/tratamento farmacológico , Linfoma Difuso de Grandes Células B/enzimologia , Proteínas de Fusão Oncogênica/metabolismo , Inibidores de Proteínas Quinases/uso terapêutico , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Quinase do Linfoma Anaplásico , Animais , Sequência de Bases , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Hospedeiro Imunocomprometido , Imunofenotipagem , Linfoma Difuso de Grandes Células B/genética , Linfoma Difuso de Grandes Células B/patologia , Camundongos , Camundongos SCID , Dados de Sequência Molecular , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/farmacologia , Pirimidinas/uso terapêutico , Receptores Proteína Tirosina Quinases/metabolismo , Indução de Remissão , Transdução de Sinais/efeitos dos fármacos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
B cell lymphoma 6 (BCL6), which encodes a transcriptional repressor, is a critical oncogene in diffuse large B cell lymphomas (DLBCLs). Although a retro-inverted BCL6 peptide inhibitor (RI-BPI) was recently shown to potently kill DLBCL cells, the underlying mechanisms remain unclear. Here, we show that RI-BPI induces a particular gene expression signature in human DLBCL cell lines that included genes associated with the actions of histone deacetylase (HDAC) and Hsp90 inhibitors. BCL6 directly repressed the expression of p300 lysine acetyltransferase (EP300) and its cofactor HLA-B-associated transcript 3 (BAT3). RI-BPI induced expression of p300 and BAT3, resulting in acetylation of p300 targets including p53 and Hsp90. Induction of p300 and BAT3 was required for the antilymphoma effects of RI-BPI, since specific blockade of either protein rescued human DLBCL cell lines from the BCL6 inhibitor. Consistent with this, combination of RI-BPI with either an HDAC inhibitor (HDI) or an Hsp90 inhibitor potently suppressed or even eradicated established human DLBCL xenografts in mice. Furthermore, HDAC and Hsp90 inhibitors independently enhanced RI-BPI killing of primary human DLBCL cells in vitro. We also show that p300-inactivating mutations occur naturally in human DLBCL patients and may confer resistance to BCL6 inhibitors. Thus, BCL6 repression of EP300 provides a basis for rational targeted combinatorial therapy for patients with DLBCL.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Proteínas de Ligação a DNA/antagonistas & inibidores , Proteína p300 Associada a E1A/antagonistas & inibidores , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Animais , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Proteína p300 Associada a E1A/genética , Proteína p300 Associada a E1A/metabolismo , Feminino , Inibidores de Histona Desacetilases/farmacologia , Humanos , Linfoma Difuso de Grandes Células B/metabolismo , Linfoma Difuso de Grandes Células B/patologia , Masculino , Camundongos , Camundongos SCID , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Proteínas Proto-Oncogênicas c-bcl-6 , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The BCL6 transcriptional repressor is the most frequently involved oncogene in diffuse large B cell lymphoma (DLBCL). We combined computer-aided drug design with functional assays to identify low-molecular-weight compounds that bind to the corepressor binding groove of the BCL6 BTB domain. One such compound disrupted BCL6/corepressor complexes in vitro and in vivo, and was observed by X-ray crystallography and NMR to bind the critical site within the BTB groove. This compound could induce expression of BCL6 target genes and kill BCL6-positive DLBCL cell lines. In xenotransplantation experiments, the compound was nontoxic and potently suppressed DLBCL tumors in vivo. The compound also killed primary DLBCLs from human patients.