RESUMO
Deubiquitylases (DUBs) are therapeutically amenable components of the ubiquitin machinery that stabilize substrate proteins. Their inhibition can destabilize oncoproteins that may otherwise be undruggable. Here, we screened for DUB vulnerabilities in multiple myeloma, an incurable malignancy with dependency on the ubiquitin proteasome system and identified OTUD6B as an oncogene that drives the G1/S-transition. LIN28B, a suppressor of microRNA biogenesis, is specified as a bona fide cell cycle-specific substrate of OTUD6B. Stabilization of LIN28B drives MYC expression at G1/S, which in turn allows for rapid S-phase entry. Silencing OTUD6B or LIN28B inhibits multiple myeloma outgrowth in vivo and high OTUD6B expression evolves in patients that progress to symptomatic multiple myeloma and results in an adverse outcome of the disease. Thus, we link proteolytic ubiquitylation with post-transcriptional regulation and nominate OTUD6B as a potential mediator of the MGUS-multiple myeloma transition, a central regulator of MYC, and an actionable vulnerability in multiple myeloma and other tumors with an activated OTUD6B-LIN28B axis.
Assuntos
Endopeptidases , MicroRNAs , Mieloma Múltiplo , Proteínas Proto-Oncogênicas c-myc , Proteínas de Ligação a RNA , Ciclo Celular , Linhagem Celular Tumoral , Endopeptidases/genética , Humanos , MicroRNAs/genética , Mieloma Múltiplo/genética , Complexo de Endopeptidases do Proteassoma/genética , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas de Ligação a RNA/genética , Ubiquitinas/metabolismoRESUMO
Evasion from drug-induced apoptosis is a crucial mechanism of cancer treatment resistance. The proapoptotic protein NOXA marks an aggressive pancreatic ductal adenocarcinoma (PDAC) subtype. To identify drugs that unleash the death-inducing potential of NOXA, we performed an unbiased drug screening experiment. In NOXA-deficient isogenic cellular models, we identified an inhibitor of the transcription factor heterodimer CBFß/RUNX1. By genetic gain and loss of function experiments, we validated that the mode of action depends on RUNX1 and NOXA. Of note is that RUNX1 expression is significantly higher in PDACs compared to normal pancreas. We show that pharmacological RUNX1 inhibition significantly blocks tumor growth in vivo and in primary patient-derived PDAC organoids. Through genome-wide analysis, we detected that RUNX1-loss reshapes the epigenetic landscape, which gains H3K27ac enrichment at the NOXA promoter. Our study demonstrates a previously unknown mechanism of NOXA-dependent cell death, which can be triggered pharmaceutically. Therefore, our data show a way to target a therapy-resistant PDAC, an unmet clinical need.
Assuntos
Apoptose/genética , Carcinoma Ductal Pancreático/genética , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Expressão Gênica , Neoplasias Pancreáticas/genética , Proteínas Proto-Oncogênicas c-bcl-2/genética , Mutações Sintéticas Letais , Carcinoma Ductal Pancreático/patologia , Subunidade alfa 2 de Fator de Ligação ao Core/antagonistas & inibidores , Humanos , Neoplasias Pancreáticas/patologia , Regiões Promotoras Genéticas , Regulação para CimaRESUMO
Aberrant activity of the SUMOylation pathway has been associated with MYC overexpression and poor prognosis in aggressive B-cell lymphoma (BCL) and other malignancies. Recently developed small-molecule inhibitors of SUMOylation (SUMOi) target the heterodimeric E1 SUMO activation complex (SAE1/UBA2). Here, we report that activated MYC signaling is an actionable molecular vulnerability in vitro and in a preclinical murine in vivo model of MYC-driven BCL. While SUMOi conferred direct effects on MYC-driven lymphoma cells, SUMO inhibition also resulted in substantial remodeling of various subsets of the innate and specific immunity in vivo. Specifically, SUMOi increased the number of memory B cells as well as cytotoxic and memory T cells, subsets that are attributed a key role within a coordinated anti-tumor immune response. In summary, our data constitute pharmacologic SUMOi as a powerful therapy in a subset of BCL causing massive remodeling of the normal B-cell and T-cell compartment.
Assuntos
Linfoma de Células B , Linfoma , Humanos , Camundongos , Animais , Proteínas Proto-Oncogênicas c-myc/metabolismo , Transdução de Sinais , Linfoma/tratamento farmacológico , Linfoma de Células B/tratamento farmacológico , Biomarcadores , Enzimas Ativadoras de Ubiquitina/metabolismoRESUMO
Targeting KRAS downstream signaling remains an important therapeutic approach in pancreatic cancer. We used primary pancreatic ductal epithelial cells and mouse models allowing the conditional expression of oncogenic KrasG12D, to investigate KRAS signaling integrators. We observed that the AP1 family member FRA1 is tightly linked to the KRAS signal and expressed in pre-malignant lesions and the basal-like subtype of pancreatic cancer. However, genetic-loss-of-function experiments revealed that FRA1 is dispensable for KrasG12D-induced pancreatic cancer development in mice. Using FRA1 gain- and loss-of-function models in an unbiased drug screen, we observed that FRA1 is a modulator of the responsiveness of pancreatic cancer to inhibitors of the RAF-MEK-ERK cascade. Mechanistically, context-dependent FRA1-associated adaptive rewiring of oncogenic ERK signaling was observed and correlated with sensitivity to inhibitors of canonical KRAS signaling. Furthermore, pharmacological-induced degradation of FRA1 synergizes with MEK inhibitors. Our studies establish FRA1 as a part of the molecular machinery controlling sensitivity to MAPK cascade inhibition allowing the development of mechanism-based therapies.
Assuntos
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Proteínas Proto-Oncogênicas c-fos , Animais , Camundongos , Carcinoma Ductal Pancreático/patologia , Linhagem Celular Tumoral , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Mutação , Neoplasias Pancreáticas/patologia , Proteínas Proto-Oncogênicas p21(ras) , Proteínas Proto-Oncogênicas c-fos/metabolismo , Neoplasias PancreáticasRESUMO
Targeted protein degradation offers new opportunities to inactivate cancer drivers and has successfully entered the clinic. Ways to induce selective protein degradation include proteolysis targeting chimera (PROTAC) technology and immunomodulatory (IMiDs) / next-generation Cereblon (CRBN) E3 ligase modulating drugs (CELMoDs). Here, we aimed to develop a MYC PROTAC based on the MYC-MAX dimerization inhibitor 10058-F4 derivative 28RH and Thalidomide, called MDEG-541. We show that a subgroup of gastrointestinal cancer cell lines and primary patient-derived organoids are MDEG-541 sensitive. Although MYC expression was regulated in a CRBN-, proteasome- and ubiquitin-dependent manner, we provide evidence that MDEG-541 induced the degradation of CRBN neosubstrates, including G1 to S phase transition 1/2 (GSPT1/2) and the Polo-like kinase 1 (PLK1). In sum, we have established a CRBN-dependent degrader of relevant cancer targets with activity in gastrointestinal cancers.
Assuntos
Antineoplásicos/farmacologia , Neoplasias Gastrointestinais/tratamento farmacológico , Talidomida/farmacologia , Tiazóis/farmacologia , Ubiquitina-Proteína Ligases/antagonistas & inibidores , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Neoplasias Gastrointestinais/metabolismo , Neoplasias Gastrointestinais/patologia , Humanos , Estrutura Molecular , Relação Estrutura-Atividade , Talidomida/síntese química , Talidomida/química , Tiazóis/síntese química , Tiazóis/química , Células Tumorais Cultivadas , Ubiquitina-Proteína Ligases/metabolismoRESUMO
BACKGROUND: Oncogenic Kras initiates and drives carcinogenesis in the pancreas by complex signaling networks, including activation of the NFκB pathway. Although recent evidence has shown that oncogenic gains in Nfκb2 collaborate with Kras in the carcinogenesis, no data at the level of genetics for the contribution of Nfκb2 is available so far. METHODS: We used Nfkb2 knock-out mice to decipher the role of the gene in Kras-driven carcinogenesis in vivo. RESULTS: We show that the Nfkb2 gene is needed for cancer initiation and progression in KrasG12D-driven models and this requirement of Nfkb2 is mechanistically connected to proliferative pathways. In contrast, Nfκb2 is dispensable in aggressive pancreatic ductal adenocarcinoma (PDAC) models relying on the simultaneous expression of the Kras oncogene and the mutated tumor suppressor p53. CONCLUSIONS: Our data add to the understanding of context-dependent requirements of oncogenic Kras signaling during pancreatic carcinogenesis.
Assuntos
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Animais , Carcinogênese/genética , Carcinoma Ductal Pancreático/genética , Genes ras , Camundongos , Pâncreas , Neoplasias Pancreáticas/genética , Proteínas Proto-Oncogênicas p21(ras)/genéticaRESUMO
OBJECTIVE: Pancreatic ductal adenocarcinoma (PDAC) still carries a dismal prognosis with an overall 5-year survival rate of 9%. Conventional combination chemotherapies are a clear advance in the treatment of PDAC; however, subtypes of the disease exist, which exhibit extensive resistance to such therapies. Genomic MYC amplifications represent a distinct subset of PDAC with an aggressive tumour biology. It is clear that hyperactivation of MYC generates dependencies that can be exploited therapeutically. The aim of the study was to find and to target MYC-associated dependencies. DESIGN: We analysed human PDAC gene expression datasets. Results were corroborated by the analysis of the small ubiquitin-like modifier (SUMO) pathway in a large PDAC cohort using immunohistochemistry. A SUMO inhibitor was used and characterised using human and murine two-dimensional, organoid and in vivo models of PDAC. RESULTS: We observed that MYC is connected to the SUMOylation machinery in PDAC. Components of the SUMO pathway characterise a PDAC subtype with a dismal prognosis and we provide evidence that hyperactivation of MYC is connected to an increased sensitivity to pharmacological SUMO inhibition. CONCLUSION: SUMO inhibitor-based therapies should be further developed for an aggressive PDAC subtype.
Assuntos
Carcinoma Ductal Pancreático/genética , Neoplasias Pancreáticas/genética , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/genética , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/metabolismo , Idoso , Animais , Apoptose , Carcinoma Ductal Pancreático/tratamento farmacológico , Linhagem Celular Tumoral , Proliferação de Células , Inibidores Enzimáticos/farmacologia , Ésteres/farmacologia , Feminino , Amplificação de Genes , Expressão Gênica , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Transplante de Neoplasias , Organoides/metabolismo , Neoplasias Pancreáticas/tratamento farmacológico , Prognóstico , Proteínas Proto-Oncogênicas c-myc/metabolismo , Pirazóis/farmacologia , Pirimidinas/farmacologia , Proteína SUMO-1/genética , Proteína SUMO-1/metabolismo , Ácidos Sulfônicos , Sumoilação/efeitos dos fármacos , Sumoilação/genética , Transcriptoma/efeitos dos fármacos , Enzimas Ativadoras de Ubiquitina/antagonistas & inibidores , Enzimas Ativadoras de Ubiquitina/genética , Enzimas de Conjugação de Ubiquitina/genética , Ubiquitinas/genética , Ubiquitinas/metabolismoRESUMO
BACKGROUND: Although the mechanistic target of rapamycin (MTOR) kinase, included in the mTORC1 and mTORC2 signalling hubs, has been demonstrated to be active in a significant fraction of patients with pancreatic ductal adenocarcinoma (PDAC), the value of the kinase as a therapeutic target needs further clarification. METHODS: We used Mtor floxed mice to analyse the function of the kinase in context of the pancreas at the genetic level. Using a dual-recombinase system, which is based on the flippase-FRT (Flp-FRT) and Cre-loxP recombination technologies, we generated a novel cellular model, allowing the genetic analysis of MTOR functions in tumour maintenance. Cross-species validation and pharmacological intervention studies were used to recapitulate genetic data in human models, including primary human 3D PDAC cultures. RESULTS: Genetic deletion of the Mtor gene in the pancreas results in exocrine and endocrine insufficiency. In established murine PDAC cells, MTOR is linked to metabolic pathways and maintains the glucose uptake and growth. Importantly, blocking MTOR genetically as well as pharmacologically results in adaptive rewiring of oncogenic signalling with activation of canonical extracellular signal-regulated kinase and phosphoinositide 3-kinase-AKT pathways. We provide evidence that interfering with such adaptive signalling in murine and human PDAC models is important in a subgroup. CONCLUSIONS: Our data suggest developing dual MTORC1/TORC2 inhibitor-based therapies for subtype-specific intervention.
Assuntos
Carcinoma Ductal Pancreático/metabolismo , Sistema de Sinalização das MAP Quinases , Neoplasias Pancreáticas/metabolismo , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo , Animais , Antineoplásicos/farmacologia , Benzoxazóis/farmacologia , Bortezomib/farmacologia , Camptotecina/farmacologia , Carcinoma Ductal Pancreático/genética , Linhagem Celular Tumoral , Sobrevivência Celular , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Alvo Mecanístico do Complexo 1 de Rapamicina/antagonistas & inibidores , Alvo Mecanístico do Complexo 2 de Rapamicina/antagonistas & inibidores , Camundongos , Neoplasias Pancreáticas/genética , Fosfatidilinositol 3-Quinase/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Pirimidinas/farmacologia , Serina-Treonina Quinases TOR/antagonistas & inibidoresRESUMO
Novel therapies are required for the treatment of metastatic renal cell carcinoma (RCC), which is associated with inoperable disease and patient death. Histone deacetylases (HDACs) are epigenetic modifiers and potential drug targets. Additional information on molecular pathways that are altered by histone deacetylase inhibitors (HDACi) in RCC cells is warranted. It should equally be delineated further which individual members of the 18 mammalian HDACs determine the survival and tumor-associated gene expression programs of such cells. Most importantly, an ongoing dispute whether HDACi promote or suppress metastasis-associated epithelial-to-mesenchymal transition (EMT) has to be resolved before HDACi are considered further as clinically relevant drugs. Here we show how HDACi affect murine and primary human RCC cells. We find that these agents induce morphological alterations resembling the metastasis-associated EMT. However, individual and proteomics-based analyses of epithelial and mesenchymal marker proteins and of EMT-associated transcription factors (EMT-TFs) reveal that HDACi do not trigger EMT. Pathway deconvolution analysis identifies reduced proliferation and apoptosis induction as key effects of HDACi. Furthermore, these drugs lead to a reduction of the cell adhesion molecule E-cadherin and of the platelet-derived growth factor receptor-ß (PDGFRß), which is a key driver of RCC metastasis formation. Accordingly, HDACi reduce the pulmonary spread of syngeneic transplanted renal carcinoma cells in mice. Specific genetic elimination of the histone deacetylases HDAC1/HDAC2 reflects the effects of pharmacological HDAC inhibition regarding growth suppression, apoptosis, and the downregulation of E-cadherin and PDGFRß. Thus, these epigenetic modifiers are non-redundant gatekeepers of cell fate and precise pharmacological targets.
Assuntos
Carcinoma de Células Renais/enzimologia , Histona Desacetilase 1/antagonistas & inibidores , Histona Desacetilase 2/antagonistas & inibidores , Inibidores de Histona Desacetilases/farmacologia , Neoplasias Renais/enzimologia , Animais , Apoptose/efeitos dos fármacos , Carcinoma de Células Renais/tratamento farmacológico , Carcinoma de Células Renais/patologia , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Inibidores de Histona Desacetilases/uso terapêutico , Humanos , Neoplasias Renais/tratamento farmacológico , Neoplasias Renais/patologia , Camundongos Endogâmicos BALB C , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Bioactive small molecules, such as drugs or metabolites, bind to proteins or other macro-molecular targets to modulate their activity, which in turn results in the observed phenotypic effects. For this reason, mapping the targets of bioactive small molecules is a key step toward unraveling the molecular mechanisms underlying their bioactivity and predicting potential side effects or cross-reactivity. Recently, large datasets of protein-small molecule interactions have become available, providing a unique source of information for the development of knowledge-based approaches to computationally identify new targets for uncharacterized molecules or secondary targets for known molecules. Here, we introduce SwissTargetPrediction, a web server to accurately predict the targets of bioactive molecules based on a combination of 2D and 3D similarity measures with known ligands. Predictions can be carried out in five different organisms, and mapping predictions by homology within and between different species is enabled for close paralogs and orthologs. SwissTargetPrediction is accessible free of charge and without login requirement at http://www.swisstargetprediction.ch.
Assuntos
Descoberta de Drogas , Proteínas/química , Software , Algoritmos , Animais , Bovinos , Humanos , Internet , Ligantes , Camundongos , Preparações Farmacêuticas/química , Proteínas/efeitos dos fármacos , Ratos , Homologia de Sequência de Aminoácidos , Interface Usuário-ComputadorRESUMO
The c-MYC (MYC afterward) oncogene is well known for driving numerous oncogenic programs. However, MYC can also induce apoptosis and this function of MYC warrants further clarification. We report here that a clinically relevant proteasome inhibitor significantly increases MYC protein levels and that endogenous MYC is necessary for the induction of apoptosis. This kind of MYC-induced cell death is mediated by enhanced expression of the pro-apoptotic BCL2 family members NOXA and BIM. Quantitative promoter-scanning chromatin immunoprecipitations (qChIP) further revealed binding of MYC to the promoters of NOXA and BIM upon proteasome inhibition, correlating with increased transcription. Both promoters are further characterized by the presence of tri-methylated lysine 4 of histone H3, marking active chromatin. We provide evidence that in our apoptosis models cell death occurs independently of p53 or ARF. Furthermore, we demonstrate that recruitment of MYC to the NOXA as well as to the BIM gene promoters depends on MYC's interaction with the zinc finger transcription factor EGR1 and an EGR1-binding site in both promoters. Our study uncovers a novel molecular mechanism by showing that the functional cooperation of MYC with EGR1 is required for bortezomib-induced cell death. This observation may be important for novel therapeutic strategies engaging the inherent pro-death function of MYC.
Assuntos
Proteínas Reguladoras de Apoptose/genética , Ácidos Borônicos/farmacologia , Proteína 1 de Resposta de Crescimento Precoce/metabolismo , Regulação Neoplásica da Expressão Gênica , Proteínas de Membrana/genética , Inibidores de Proteassoma/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas Proto-Oncogênicas/genética , Pirazinas/farmacologia , Animais , Apoptose/genética , Proteínas Reguladoras de Apoptose/fisiologia , Proteína 11 Semelhante a Bcl-2 , Sítios de Ligação , Bortezomib , Linhagem Celular Tumoral , Células Cultivadas , Genes p16 , Genes p53 , Proteínas de Membrana/fisiologia , Camundongos , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas/fisiologia , Proteínas Proto-Oncogênicas c-bcl-2/fisiologia , Transcrição GênicaRESUMO
Survivin belongs to the family of apoptosis inhibitors (IAPs), which antagonizes the induction of cell death. Dysregulated expression of IAPs is frequently observed in cancers, and the high levels of survivin in tumors compared to normal adult tissues make it an attractive target for pharmacological interventions. The small imidazolium-based compound YM155 has recently been reported to block the expression of survivin via inhibition of the survivin promoter. Recent data, however, question that this is the sole and main effect of this drug, which is already being tested in ongoing clinical studies. Here, we critically review the current data on YM155 and other new experimental agents supposed to antagonize survivin. We summarize how cells from various tumor entities and with differential expression of the tumor suppressor p53 respond to this agent in vitro and as murine xenografts. Additionally, we recapitulate clinical trials conducted with YM155. Our article further considers the potency of YM155 in combination with other anti-cancer agents and epigenetic modulators. We also assess state-of-the-art data on the sometimes very promiscuous molecular mechanisms affected by YM155 in cancer cells.
Assuntos
Imidazóis/administração & dosagem , Proteínas Inibidoras de Apoptose/biossíntese , Naftoquinonas/administração & dosagem , Neoplasias/genética , Animais , Apoptose/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Proteínas Inibidoras de Apoptose/antagonistas & inibidores , Proteínas Inibidoras de Apoptose/genética , Camundongos , Neoplasias/patologia , Regiões Promotoras Genéticas/efeitos dos fármacos , Survivina , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The SwissBioisostere database (http://www.swissbioisostere.ch) contains information on molecular replacements and their performance in biochemical assays. It is meant to provide researchers in drug discovery projects with ideas for bioisosteric modifications of their current lead molecule, as well as to give interested scientists access to the details on particular molecular replacements. As of August 2012, the database contains 21,293,355 datapoints corresponding to 5,586,462 unique replacements that have been measured in 35,039 assays against 1948 molecular targets representing 30 target classes. The accessible data were created through detection of matched molecular pairs and mining bioactivity data in the ChEMBL database. The SwissBioisostere database is hosted by the Swiss Institute of Bioinformatics and available via a web-based interface.
Assuntos
Bases de Dados de Compostos Químicos , Desenho de Fármacos , Ligantes , Internet , Interface Usuário-ComputadorRESUMO
Epithelial-to-mesenchymal transition (EMT) is a classical cellular plasticity process induced by various cell-intrinsic and -extrinsic triggers. Although prominent factors, such as TGFß, mediate EMT via well-characterized pathways, alternative avenues are less well understood. Transcriptomic subtyping of pancreatic ductal adenocarcinoma (PDAC) has demonstrated that basal-like PDACs enrich a mesenchymal-like expression program, emphasizing the relevance of EMT in the disease. In this issue of Cancer Research, Brown and colleagues demonstrate the tight connection of EMT to hypoxia. Through a detailed mechanistic analysis, the authors deciphered that hypoxia-induced signals are integrated by the histone H3 lysine 36 di-methylation (H3K36me2) mark. On the one hand, hypoxia decreased activity of the H3K36me2 eraser KDM2A, while on the other hand promoting stabilization of the H3K36me2 writer NSD2. Hypoxia diminished the expression of a set of serine-threonine phosphatases, subsequently resulting in SRC kinase family-dependent activation of canonical MEK, ERK, and JNK signaling to impinge on NSD2 expression. In addition, reduced expression of the protein phosphatase PP2Cδ was linked to increased NSD2 protein expression. These discoveries illuminate the close relationship of hypoxia signaling to the epigenetic machinery and cellular plasticity processes. See related article by Brown et al., p. 1764.
Assuntos
Carcinoma Ductal Pancreático , Epigênese Genética , Transição Epitelial-Mesenquimal , Neoplasias Pancreáticas , Humanos , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/metabolismo , Transição Epitelial-Mesenquimal/genética , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patologia , Carcinoma Ductal Pancreático/metabolismo , Histonas/metabolismo , Histonas/genética , Regulação Neoplásica da Expressão GênicaRESUMO
Cancer cells must develop strategies to adapt to the dynamically changing stresses caused by intrinsic or extrinsic processes, or therapeutic agents. Metabolic adaptability is crucial to mitigate such challenges. Considering metabolism as a central node of adaptability, it is focused on an energy sensor, the AMP-activated protein kinase (AMPK). In a subtype of pancreatic ductal adenocarcinoma (PDAC) elevated AMPK expression and phosphorylation is identified. Using drug repurposing that combined screening experiments and chemoproteomic affinity profiling, it is identified and characterized PF-3758309, initially developed as an inhibitor of PAK4, as an AMPK inhibitor. PF-3758309 shows activity in pre-clinical PDAC models, including primary patient-derived organoids. Genetic loss-of-function experiments showed that AMPK limits the induction of ferroptosis, and consequently, PF-3758309 treatment restores the sensitivity toward ferroptosis inducers. The work established a chemical scaffold for the development of specific AMPK-targeting compounds and deciphered the framework for the development of AMPK inhibitor-based combination therapies tailored for PDAC.
Assuntos
Proteínas Quinases Ativadas por AMP , Ferroptose , Neoplasias Pancreáticas , Ferroptose/efeitos dos fármacos , Humanos , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Proteínas Quinases Ativadas por AMP/metabolismo , Proteínas Quinases Ativadas por AMP/genética , Linhagem Celular Tumoral , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Camundongos , AnimaisRESUMO
Pancreatic ductal adenocarcinoma (PDAC) represents the fourth leading cause of cancer death in the western world, with a 5-year survival rate below 5%. Murine double minute 2 (Mdm2) is an important negative regulator of the tumor suppressor p53. Reactivation of wild-type p53 is a promising treatment strategy, and inhibitors of Mdm2 have already entered clinical trials. To investigate the effects of Mdm2 inhibitors in PDAC, we used a murine cell line platform with a genetically defined status of p53. Here, we describe that Mdm2 inhibitors can act on a subset of murine PDAC cell lines p53 independently. Furthermore, we observed that Mdm2 inhibitors increase the sensitivity of murine PDAC cell lines toward topoisomerase II inhibitors by inducing effector caspase-independent cell death. The combination of Mdm2 inhibitors with topoisomerase II inhibitors acts independent of the survival factor NFκB/RelA. Mechanistically, Mdm2 inhibitors increase topoisomerase II inhibitor-induced DNA double-strand breaks. We show that Mdm2 binds to Nbs1 of the Mre11-Rad50-Nijmegen breakage syndrome (Nbs) 1 DNA repair complex. In addition, we provide evidence that Mdm2 inhibitors delay DNA repair. These findings may help to design novel therapeutic strategies to overcome therapeutic resistance of PDAC.
Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Indóis/farmacologia , Neoplasias Pancreáticas/tratamento farmacológico , Proteínas Proto-Oncogênicas c-mdm2/antagonistas & inibidores , Pirrolidinonas/farmacologia , Inibidores da Topoisomerase II/farmacologia , Clorometilcetonas de Aminoácidos/farmacologia , Animais , Western Blotting , Linhagem Celular Tumoral , Dano ao DNA/efeitos dos fármacos , Desoxicitidina/análogos & derivados , Desoxicitidina/farmacologia , Modelos Animais de Doenças , Doxorrubicina/farmacologia , Sinergismo Farmacológico , Etoposídeo/farmacologia , Imidazóis/farmacologia , Imuno-Histoquímica , Imunoprecipitação , Camundongos , Neoplasias Pancreáticas/metabolismo , Piperazinas/farmacologia , GencitabinaRESUMO
Understanding molecular recognition is one major requirement for drug discovery and design. Physicochemical and shape complementarity between two binding partners is the driving force during complex formation. In this study, the impact of shape within this process is analyzed. Protein binding pockets and co-crystallized ligands are represented by normalized principal moments of inertia ratios (NPRs). The corresponding descriptor space is triangular, with its corners occupied by spherical, discoid, and elongated shapes. An analysis of a selected set of sc-PDB complexes suggests that pockets and bound ligands avoid spherical shapes, which are, however, prevalent in small unoccupied pockets. Furthermore, a direct shape comparison confirms previous studies that on average only one third of a pocket is filled by its bound ligand, supplemented by a 50 % subpocket coverage. In this study, we found that shape complementary is expressed by low pairwise shape distances in NPR space, short distances between the centers-of-mass, and small deviations in the angle between the first principal ellipsoid axes. Furthermore, it is assessed how different binding pocket parameters are related to bioactivity and binding efficiency of the co-crystallized ligand. In addition, the performance of different shape and size parameters of pockets and ligands is evaluated in a virtual screening scenario performed on four representative targets.
Assuntos
Ligantes , Modelos Moleculares , Proteínas/química , Cristalografia por Raios X , Descoberta de Drogas , Humanos , Ligação Proteica , Conformação ProteicaRESUMO
Epigenetic alterations have been identified in various tumor types. In part, these alterations are mediated via increased histone deacetylase activity. Although preclinical results of monotherapies with histone deacetylase inhibitors (HDACi) are promising, success in clinical trials is limited. Reasons for these limitations may be de novo or acquired resistance to HDAC inhibitors that could be overcome with rational combination therapies. This requires knowledge of resistance mechanism along with the involved genetic networks. One way to identify such genetic networks is the implementation of a CRISPR-based technology allowing transcriptional repression (CRISPRi) and activation (CRISPRa) at a genome-wide scale. We describe a simple approach to amplify and validate sgRNA libraries, generate a myeloid progenitor cell line expressing catalytically dead Cas9 (dCas9) fusion proteins with transcriptional effectors to repress or activate genetic regions of interest and demonstrate a complementary genome-wide HDACi resistance screening approach. Furthermore, we present bioinformatics tools for quality control and analysis of the sequencing data.
Assuntos
Redes Reguladoras de Genes , Inibidores de Histona Desacetilases , Inibidores de Histona Desacetilases/farmacologia , Proteína 9 Associada à CRISPR , Expressão Gênica , Histona Desacetilases/genética , Sistemas CRISPR-CasRESUMO
Epigenetic modifiers of the histone deacetylase (HDAC) family are often dysregulated in cancer cells. Experiments with small molecule HDAC inhibitors (HDACi) have proven that HDACs are a vulnerability of transformed cells. We evaluated a novel hydroxamic acid-based HDACi (KH16; termed yanostat) in human pancreatic ductal adenocarcinoma (PDAC) cells, short- and long-term cultured colorectal cancer (CRC) cells, and retinal pigment epithelial cells. We show that KH16 induces cell cycle arrest and apoptosis, both time and dose dependently in PDAC and CRC cells. This is associated with altered expression of BCL2 family members controlling intrinsic apoptosis. Recent data illustrate that PDAC cells frequently have an altered expression of the pro-apoptotic BH3-only protein NOXA and that HDACi induce an accumulation of NOXA. Using PDAC cells with a deletion of NOXA by CRISPR-Cas9, we found that a lack of NOXA delayed apoptosis induction by KH16. These results suggest that KH16 is a new chemotype of hydroxamic acid HDACi with superior activity against solid tumor-derived cells. Thus, KH16 is a scaffold for future research on compounds with nanomolar activity against HDACs.