RESUMO
Chronic myeloid leukaemia (CML) is driven by the activity of the BCR-ABL1 fusion oncoprotein. ABL1 kinase inhibitors have improved the clinical outcomes for patients with CML, with over 80% of patients treated with imatinib surviving for more than 10 years. Second-generation ABL1 kinase inhibitors induce more potent molecular responses in both previously untreated and imatinib-resistant patients with CML. Studies in patients with chronic-phase CML have shown that around 50% of patients who achieve and maintain undetectable BCR-ABL1 transcript levels for at least 2 years remain disease-free after the withdrawal of treatment. Here we characterize ABL001 (asciminib), a potent and selective allosteric ABL1 inhibitor that is undergoing clinical development testing in patients with CML and Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukaemia. In contrast to catalytic-site ABL1 kinase inhibitors, ABL001 binds to the myristoyl pocket of ABL1 and induces the formation of an inactive kinase conformation. ABL001 and second-generation catalytic inhibitors have similar cellular potencies but distinct patterns of resistance mutations, with genetic barcoding studies revealing pre-existing clonal populations with no shared resistance between ABL001 and the catalytic inhibitor nilotinib. Consistent with this profile, acquired resistance was observed with single-agent therapy in mice; however, the combination of ABL001 and nilotinib led to complete disease control and eradicated CML xenograft tumours without recurrence after the cessation of treatment.
Assuntos
Sítio Alostérico/efeitos dos fármacos , Proteínas de Fusão bcr-abl/antagonistas & inibidores , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Niacinamida/análogos & derivados , Pirazóis/farmacologia , Regulação Alostérica/efeitos dos fármacos , Animais , Domínio Catalítico/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Dasatinibe/uso terapêutico , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Quimioterapia Combinada , Proteínas de Fusão bcr-abl/química , Proteínas de Fusão bcr-abl/genética , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/enzimologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Camundongos , Mutação , Niacinamida/farmacologia , Niacinamida/uso terapêutico , Pirazóis/uso terapêutico , Pirimidinas/farmacologia , Pirimidinas/uso terapêutico , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The non-receptor protein tyrosine phosphatase SHP2, encoded by PTPN11, has an important role in signal transduction downstream of growth factor receptor signalling and was the first reported oncogenic tyrosine phosphatase. Activating mutations of SHP2 have been associated with developmental pathologies such as Noonan syndrome and are found in multiple cancer types, including leukaemia, lung and breast cancer and neuroblastoma. SHP2 is ubiquitously expressed and regulates cell survival and proliferation primarily through activation of the RASERK signalling pathway. It is also a key mediator of the programmed cell death 1 (PD-1) and B- and T-lymphocyte attenuator (BTLA) immune checkpoint pathways. Reduction of SHP2 activity suppresses tumour cell growth and is a potential target of cancer therapy. Here we report the discovery of a highly potent (IC50 = 0.071 µM), selective and orally bioavailable small-molecule SHP2 inhibitor, SHP099, that stabilizes SHP2 in an auto-inhibited conformation. SHP099 concurrently binds to the interface of the N-terminal SH2, C-terminal SH2, and protein tyrosine phosphatase domains, thus inhibiting SHP2 activity through an allosteric mechanism. SHP099 suppresses RASERK signalling to inhibit the proliferation of receptor-tyrosine-kinase-driven human cancer cells in vitro and is efficacious in mouse tumour xenograft models. Together, these data demonstrate that pharmacological inhibition of SHP2 is a valid therapeutic approach for the treatment of cancers.
Assuntos
Neoplasias/tratamento farmacológico , Neoplasias/enzimologia , Piperidinas/farmacologia , Proteína Tirosina Fosfatase não Receptora Tipo 11/antagonistas & inibidores , Pirimidinas/farmacologia , Receptores Proteína Tirosina Quinases/metabolismo , Regulação Alostérica/efeitos dos fármacos , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Feminino , Humanos , Concentração Inibidora 50 , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos , Camundongos Nus , Modelos Moleculares , Neoplasias/patologia , Proteína Oncogênica p21(ras)/metabolismo , Piperidinas/química , Piperidinas/uso terapêutico , Inibidores de Proteínas Quinases/farmacologia , Estabilidade Proteica/efeitos dos fármacos , Estrutura Terciária de Proteína/efeitos dos fármacos , Proteína Tirosina Fosfatase não Receptora Tipo 11/química , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Proteína Tirosina Fosfatase não Receptora Tipo 11/metabolismo , Pirimidinas/química , Pirimidinas/uso terapêutico , Reprodutibilidade dos Testes , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Defects in epigenetic regulation play a fundamental role in the development of cancer, and epigenetic regulators have recently emerged as promising therapeutic candidates. We therefore set out to systematically interrogate epigenetic cancer dependencies by screening an epigenome-focused deep-coverage design shRNA (DECODER) library across 58 cancer cell lines. This screen identified BRM/SMARCA2, a DNA-dependent ATPase of the mammalian SWI/SNF (mSWI/SNF) chromatin remodeling complex, as being essential for the growth of tumor cells that harbor loss of function mutations in BRG1/SMARCA4. Depletion of BRM in BRG1-deficient cancer cells leads to a cell cycle arrest, induction of senescence, and increased levels of global H3K9me3. We further demonstrate the selective dependency of BRG1-mutant tumors on BRM in vivo. Genetic alterations of the mSWI/SNF chromatin remodeling complexes are the most frequent among chromatin regulators in cancers, with BRG1/SMARCA4 mutations occurring in â¼10-15% of lung adenocarcinomas. Our findings position BRM as an attractive therapeutic target for BRG1 mutated cancers. Because BRG1 and BRM function as mutually exclusive catalytic subunits of the mSWI/SNF complex, we propose that such synthetic lethality may be explained by paralog insufficiency, in which loss of one family member unveils critical dependence on paralogous subunits. This concept of "cancer-selective paralog dependency" may provide a more general strategy for targeting other tumor suppressor lesions/complexes with paralogous subunits.
Assuntos
DNA Helicases/deficiência , Epigênese Genética/fisiologia , Complexos Multiproteicos/genética , Neoplasias/genética , Proteínas Nucleares/deficiência , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética , Western Blotting , Pontos de Checagem do Ciclo Celular/genética , Linhagem Celular Tumoral , Senescência Celular/genética , Técnicas de Silenciamento de Genes , Biblioteca Gênica , Histonas/metabolismo , Humanos , Imunoprecipitação , Complexos Multiproteicos/metabolismo , RNA Interferente Pequeno/genética , Fatores de Transcrição/metabolismoRESUMO
Errors in mitosis can provide a source of the genomic instability that is typically associated with tumorigenesis. Many mitotic regulators are aberrantly expressed in tumour cells. These proteins could therefore make useful therapeutic targets. The kinases Aurora-A, -B and -C represent a family of such targets and several small-molecule inhibitors have been shown to block their function. Not only have these inhibitors advanced our understanding of mitosis, but, importantly, their in vivo antitumour activity has recently been reported. What have these studies taught us about the therapeutic potential of inhibiting this family of kinases?
Assuntos
Antineoplásicos/uso terapêutico , Inibidores Enzimáticos/uso terapêutico , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Animais , Aurora Quinases , Humanos , Mitose/genética , Proteínas Serina-Treonina Quinases/genéticaRESUMO
CD137 (4-1BB) is a co-stimulatory receptor on immune cells and Nectin-4 is a cell adhesion molecule that is overexpressed in multiple tumor types. Using a series of poly(ethylene glycol) (PEG)-based linkers, synthetic bicyclic peptides targeting CD137 were conjugated to Bicycles targeting Nectin-4. The resulting bispecific molecules were potent CD137 agonists that require the presence of both Nectin-4-expressing tumor cells and CD137-expressing immune cells for activity. A multipronged approach was taken to optimize these Bicycle tumor-targeted immune cell agonists by exploring the impact of chemical configuration, binding affinity, and pharmacokinetics on CD137 agonism and antitumor activity. This effort resulted in the discovery of BT7480, which elicited robust CD137 agonism and maximum antitumor activity in syngeneic mouse models. A tumor-targeted approach to CD137 agonism using low-molecular-weight, short-acting molecules with high tumor penetration is a yet unexplored path in the clinic, where emerging data suggest that persistent target engagement, characteristic of biologics, may lead to suboptimal immune response.
Assuntos
Neoplasias , Animais , Moléculas de Adesão Celular , Camundongos , Nectinas , Neoplasias/tratamento farmacológico , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/metabolismoRESUMO
Multiple tumor types overexpress Nectin-4 and the antibody-drug conjugate (ADC), enfortumab vedotin (EV) shows striking efficacy in clinical trials for metastatic urothelial cancer, which expresses high levels of Nectin-4, validating Nectin-4 as a clinical target for toxin delivery in this indication. Despite excellent data in urothelial cancer, little efficacy data are reported for EV in other Nectin-4 expressing tumors and EV therapy can produce significant toxicities in many patients, frequently leading to discontinuation of treatment. Thus, additional approaches to this target with the potential to extend utility and reduce toxicity are warranted. We describe the preclinical development of BT8009, a "Bicycle Toxin Conjugate" (BTC) consisting of a Nectin-4-binding bicyclic peptide, a cleavable linker system and the cell penetrant toxin mono-methylauristatin E (MMAE). BT8009 shows significant antitumor activity in preclinical tumor models, across a variety of cancer indications and is well tolerated in preclinical safety studies. In several models, it shows superior or equivalent antitumor activity to an EV analog. As a small hydrophilic peptide-based drug BT8009 rapidly diffuses from the systemic circulation, through tissues to penetrate the tumor and target tumor cells. It is renally eliminated from the circulation, with a half-life of 1-2 hours in rat and non-human primate. These physical and PK characteristics differentiate BT8009 from ADCs and may provide benefit in terms of tumor penetration and reduced systemic exposure. BT8009 is currently in a Phase 1/2 multicenter clinical trial across the US, Canada, and Europe, enrolling patients with advanced solid tumors associated with Nectin-4 expression.
Assuntos
Carcinoma de Células de Transição , Imunoconjugados , Imunotoxinas , Ratos , Animais , Nectinas , Ciclismo , Imunoconjugados/farmacologia , Imunoconjugados/uso terapêutico , Moléculas de Adesão Celular/metabolismo , Carcinoma de Células de Transição/tratamento farmacológicoRESUMO
BACKGROUND: CD137 (4-1BB) is an immune costimulatory receptor with high therapeutic potential in cancer. We are creating tumor target-dependent CD137 agonists using a novel chemical approach based on fully synthetic constrained bicyclic peptide (Bicycle®) technology. Nectin-4 is overexpressed in multiple human cancers that may benefit from CD137 agonism. To this end, we have developed BT7480, a novel, first-in-class, Nectin-4/CD137 Bicycle tumor-targeted immune cell agonist™ (Bicycle TICA™). METHODS: Nectin-4 and CD137 co-expression analyses in primary human cancer samples was performed. Chemical conjugation of two CD137 Bicycles to a Nectin-4 Bicycle led to BT7480, which was then evaluated using a suite of in vitro and in vivo assays to characterize its pharmacology and mechanism of action. RESULTS: Transcriptional profiling revealed that Nectin-4 and CD137 were co-expressed in a variety of human cancers with high unmet need and spatial proteomic imaging found CD137-expressing immune cells were deeply penetrant within the tumor near Nectin-4-expressing cancer cells. BT7480 binds potently, specifically, and simultaneously to Nectin-4 and CD137. In co-cultures of human peripheral blood mononuclear cells and tumor cells, this co-ligation causes robust Nectin-4-dependent CD137 agonism that is more potent than an anti-CD137 antibody agonist. Treatment of immunocompetent mice bearing Nectin-4-expressing tumors with BT7480 elicited a profound reprogramming of the tumor immune microenvironment including an early and rapid myeloid cell activation that precedes T cell infiltration and upregulation of cytotoxicity-related genes. BT7480 induces complete tumor regressions and resistance to tumor re-challenge. Importantly, antitumor activity is not dependent on continuous high drug levels in the plasma since a once weekly dosing cycle provides maximum antitumor activity despite minimal drug remaining in the plasma after day 2. BT7480 appears well tolerated in both rats and non-human primates at doses far greater than those expected to be clinically relevant, including absence of the hepatic toxicity observed with non-targeted CD137 agonists. CONCLUSION: BT7480 is a highly potent Nectin-4-dependent CD137 agonist that produces complete regressions and antitumor immunity with only intermittent drug exposure in syngeneic mouse tumor models and is well tolerated in preclinical safety species. This work supports the clinical investigation of BT7480 for the treatment of cancer in humans.
Assuntos
Imunoterapia/métodos , Neoplasias/tratamento farmacológico , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/metabolismo , Animais , Humanos , Camundongos , Neoplasias/imunologia , Ratos , Microambiente TumoralRESUMO
BACKGROUND: In contrast to immune checkpoint inhibitors, the use of antibodies as agonists of immune costimulatory receptors as cancer therapeutics has largely failed. We sought to address this problem using a new class of modular synthetic drugs, termed tumor-targeted immune cell agonists (TICAs), based on constrained bicyclic peptides (Bicycles). METHODS: Phage libraries displaying Bicycles were panned for binders against tumor necrosis factor (TNF) superfamily receptors CD137 and OX40, and tumor antigens EphA2, Nectin-4 and programmed death ligand 1. The CD137 and OX40 Bicycles were chemically conjugated to tumor antigen Bicycles with different linkers and stoichiometric ratios of binders to obtain a library of low molecular weight TICAs (MW <8 kDa). The TICAs were evaluated in a suite of in vitro and in vivo assays to characterize their pharmacology and mechanism of action. RESULTS: Linking Bicycles against costimulatory receptors (e.g., CD137) to Bicycles against tumor antigens (e.g., EphA2) created potent agonists that activated the receptors selectively in the presence of tumor cells expressing these antigens. An EphA2/CD137 TICA (BCY12491) efficiently costimulated human peripheral blood mononuclear cells in vitro in the presence of EphA2 expressing tumor cell lines as measured by the increased secretion of interferon γ and interleukin-2. Treatment of C57/Bl6 mice transgenic for the human CD137 extracellular domain (huCD137) bearing EphA2-expressing MC38 tumors with BCY12491 resulted in the infiltration of CD8+ T cells, elimination of tumors and generation of immunological memory. BCY12491 was cleared quickly from the circulation (plasma t1/2 in mice of 1-2 hr), yet intermittent dosing proved effective. CONCLUSION: Tumor target-dependent CD137 agonism using a novel chemical approach (TICAs) afforded elimination of tumors with only intermittent dosing suggesting potential for a wide therapeutic index in humans. This work unlocks a new path to effective cancer immunotherapy via agonism of TNF superfamily receptors.
Assuntos
Neoplasias/tratamento farmacológico , Peptídeos Cíclicos/administração & dosagem , Receptor EphA2/agonistas , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/agonistas , Células A549 , Animais , Antígenos de Neoplasias/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Linhagem Celular Tumoral , Feminino , Células HT29 , Humanos , Células Jurkat , Camundongos , Camundongos Transgênicos , Neoplasias/genética , Neoplasias/imunologia , Células PC-3 , Biblioteca de Peptídeos , Peptídeos Cíclicos/química , Peptídeos Cíclicos/farmacologia , Receptores OX40/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
In this article we review the basis for current anti-mitotic, anti-cancer, therapy and the potential for Aurora B kinase inhibitors as a new differentiated class of agents--"mitotic drivers". We review the current understanding of Aurora B inhibition from basic cell biology to inhibitors currently undergoing clinical trials.
Assuntos
Antineoplásicos/uso terapêutico , Mitose , Neoplasias/metabolismo , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Animais , Antineoplásicos/química , Aurora Quinase B , Aurora Quinases , Ciclo Celular , Modelos Animais de Doenças , Resistencia a Medicamentos Antineoplásicos , Humanos , Oncologia/métodos , Oncologia/tendências , Microtúbulos/efeitos dos fármacos , Modelos Biológicos , Inibidores de Proteínas Quinases/química , Fuso Acromático/efeitos dos fármacosRESUMO
The EphA2 receptor is found at high levels in tumors and low levels in normal tissue and high EphA2 expression in biopsies is a predictor of poor outcome in patients. Drug discovery groups have therefore sought to develop EphA2-based therapies using small molecule, peptide, and nanoparticle-based approaches (1-3). However, until now only EphA2-targeting antibody-drug conjugates (ADC) have entered clinical development. For example, MEDI-547 is an EphA2-targeting ADC that displayed encouraging antitumor activity in preclinical models and progressed to phase I clinical testing in man. Here we describe the development of BT5528, a bicyclic peptide ("Bicycle") conjugated to the auristatin derivative maleimidocaproyl-monomethyl auristatin E to generate the Bicycle toxin conjugate BT5528. The report compares and contrasts the Pharmacokinetics (PK) characteristics of antibody and Bicycle-based targeting systems and discusses how the PK and payload characteristics of different delivery systems impact the efficacy-toxicity trade off which is key to the development of successful cancer therapies. We show that BT5528 gives rise to rapid update into tumors and fast renal elimination followed by persistent toxin levels in tumors without prolonged exposure of parent drug in the vasculature. This fast in, fast out kinetics gave rise to more favorable toxicology findings in rats and monkeys than were observed with MEDI-547 in preclinical and clinical studies.Graphical Abstract: http://mct.aacrjournals.org/content/molcanther/19/7/1385/F1.large.jpg.
Assuntos
Antineoplásicos/farmacologia , Sistemas de Liberação de Medicamentos , Fibrossarcoma/tratamento farmacológico , Oligopeptídeos/química , Peptídeos Cíclicos/farmacologia , Receptor EphA2/metabolismo , Animais , Anticorpos Monoclonais/farmacologia , Antineoplásicos/farmacocinética , Apoptose , Proliferação de Células , Feminino , Fibrossarcoma/metabolismo , Fibrossarcoma/patologia , Humanos , Imunotoxinas/farmacocinética , Imunotoxinas/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Oligopeptídeos/administração & dosagem , Peptídeos Cíclicos/farmacocinética , Receptor EphA2/genética , Distribuição Tecidual , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The Aurora/Ipl1 family of protein kinases plays multiple roles in mitosis and cytokinesis. Here, we describe ZM447439, a novel selective Aurora kinase inhibitor. Cells treated with ZM447439 progress through interphase, enter mitosis normally, and assemble bipolar spindles. However, chromosome alignment, segregation, and cytokinesis all fail. Despite the presence of maloriented chromosomes, ZM447439-treated cells exit mitosis with normal kinetics, indicating that the spindle checkpoint is compromised. Indeed, ZM447439 prevents mitotic arrest after exposure to paclitaxel. RNA interference experiments suggest that these phenotypes are due to inhibition of Aurora B, not Aurora A or some other kinase. In the absence of Aurora B function, kinetochore localization of the spindle checkpoint components BubR1, Mad2, and Cenp-E is diminished. Furthermore, inhibition of Aurora B kinase activity prevents the rebinding of BubR1 to metaphase kinetochores after a reduction in centromeric tension. Aurora B kinase activity is also required for phosphorylation of BubR1 on entry into mitosis. Finally, we show that BubR1 is not only required for spindle checkpoint function, but is also required for chromosome alignment. Together, these results suggest that by targeting checkpoint proteins to kinetochores, Aurora B couples chromosome alignment with anaphase onset.
Assuntos
Anáfase/genética , Segregação de Cromossomos/genética , Células Eucarióticas/enzimologia , Cinetocoros/metabolismo , Mitose/genética , Proteínas Serina-Treonina Quinases/genética , Anáfase/efeitos dos fármacos , Aurora Quinase B , Aurora Quinases , Benzamidas/farmacologia , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ciclo Celular , Proteínas Cromossômicas não Histona/genética , Proteínas Cromossômicas não Histona/metabolismo , Segregação de Cromossomos/efeitos dos fármacos , Replicação do DNA/efeitos dos fármacos , Replicação do DNA/genética , Inibidores Enzimáticos/farmacologia , Células Eucarióticas/efeitos dos fármacos , Células Eucarióticas/ultraestrutura , Genes cdc/efeitos dos fármacos , Células HeLa , Humanos , Cinetocoros/efeitos dos fármacos , Proteínas Mad2 , Mitose/efeitos dos fármacos , Paclitaxel/farmacologia , Fosforilação/efeitos dos fármacos , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Quinazolinas/farmacologia , Proteínas Repressoras/efeitos dos fármacos , Proteínas Repressoras/genética , Fuso Acromático/efeitos dos fármacos , Fuso Acromático/genética , Proteína Supressora de Tumor p53/efeitos dos fármacos , Proteína Supressora de Tumor p53/genéticaRESUMO
A new class of 1-acetanilide-4-aminopyrazole-substituted quinazoline Aurora kinase inhibitors has been discovered possessing highly potent cellular activity. Continuous infusion into athymic mice bearing SW620 tumors of the soluble phosphate derivative 2 led to dose-proportional exposure of the des-phosphate compound 8 with a high-unbound fraction. The combination of potent cell activity and high free-drug exposure led to pharmacodynamic changes in the tumor at low doses, indicative of Aurora B-kinase inhibition and a reduction in tumor volume.
Assuntos
Neoplasias do Colo/tratamento farmacológico , Inibidores de Proteínas Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Pirazóis/química , Quinazolinas/síntese química , Quinazolinas/farmacologia , Animais , Aurora Quinase B , Aurora Quinases , Ciclo Celular/efeitos dos fármacos , Neoplasias do Colo/enzimologia , Neoplasias do Colo/patologia , Citocromo P-450 CYP3A/metabolismo , Eletrofisiologia , Canais de Potássio Éter-A-Go-Go/metabolismo , Histonas/metabolismo , Humanos , Masculino , Camundongos , Camundongos Nus , Estrutura Molecular , Fosforilação/efeitos dos fármacos , Proteínas Serina-Treonina Quinases/metabolismo , Quinazolinas/química , Ratos , Ratos Wistar , Relação Estrutura-Atividade , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
PURPOSE: In the current study, we examined the in vivo effects of AZD1152, a novel and specific inhibitor of Aurora kinase activity (with selectivity for Aurora B). EXPERIMENTAL DESIGN: The pharmacodynamic effects and efficacy of AZD1152 were determined in a panel of human tumor xenograft models. AZD1152 was dosed via several parenteral (s.c. osmotic mini-pump, i.p., and i.v.) routes. RESULTS: AZD1152 potently inhibited the growth of human colon, lung, and hematologic tumor xenografts (mean tumor growth inhibition range, 55% to > or =100%; P < 0.05) in immunodeficient mice. Detailed pharmacodynamic analysis in colorectal SW620 tumor-bearing athymic rats treated i.v. with AZD1152 revealed a temporal sequence of phenotypic events in tumors: transient suppression of histone H3 phosphorylation followed by accumulation of 4N DNA in cells (2.4-fold higher compared with controls) and then an increased proportion of polyploid cells (>4N DNA, 2.3-fold higher compared with controls). Histologic analysis showed aberrant cell division that was concurrent with an increase in apoptosis in AZD1152-treated tumors. Bone marrow analyses revealed transient myelosuppression with the drug that was fully reversible following cessation of AZD1152 treatment. CONCLUSIONS: These data suggest that selective targeting of Aurora B kinase may be a promising therapeutic approach for the treatment of a range of malignancies. In addition to the suppression of histone H3 phosphorylation, determination of tumor cell polyploidy and apoptosis may be useful biomarkers for this class of therapeutic agent. AZD1152 is currently in phase I trials.
Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias Experimentais/tratamento farmacológico , Organofosfatos/farmacologia , Quinazolinas/farmacologia , Animais , Aurora Quinase B , Aurora Quinases , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Citometria de Fluxo , Humanos , Camundongos , Camundongos Nus , Proteínas Serina-Treonina Quinases/efeitos dos fármacos , Ratos , Transplante HeterólogoRESUMO
Perturbed epigenomic programs play key roles in tumorigenesis, and chromatin modulators are candidate therapeutic targets in various human cancer types. To define singular and shared dependencies on DNA and histone modifiers and transcription factors in poorly differentiated adult and pediatric cancers, we conducted a targeted shRNA screen across 59 cell lines of 6 cancer types. Here, we describe the TRPS1 transcription factor as a strong breast cancer-specific hit, owing largely to lineage-restricted expression. Knockdown of TRPS1 resulted in perturbed mitosis, apoptosis, and reduced tumor growth. Integrated analysis of TRPS1 transcriptional targets, chromatin binding, and protein interactions revealed that TRPS1 is associated with the NuRD repressor complex. These findings uncover a transcriptional network that is essential for breast cancer cell survival and propagation.
Assuntos
Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Linhagem da Célula , Proteínas de Ligação a DNA/metabolismo , Fatores de Transcrição/metabolismo , Transcrição Gênica , Linhagem Celular Tumoral , Sobrevivência Celular/genética , Feminino , Células HEK293 , Humanos , Complexo Mi-2 de Remodelação de Nucleossomo e Desacetilase/metabolismo , Ligação Proteica , RNA Interferente Pequeno/metabolismo , Proteínas Repressoras/metabolismo , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/patologiaRESUMO
Resistance to the RAF inhibitor vemurafenib arises commonly in melanomas driven by the activated BRAF oncogene. Here, we report antitumor properties of RAF709, a novel ATP-competitive kinase inhibitor with high potency and selectivity against RAF kinases. RAF709 exhibited a mode of RAF inhibition distinct from RAF monomer inhibitors such as vemurafenib, showing equal activity against both RAF monomers and dimers. As a result, RAF709 inhibited MAPK signaling activity in tumor models harboring either BRAFV600 alterations or mutant N- and KRAS-driven signaling, with minimal paradoxical activation of wild-type RAF. In cell lines and murine xenograft models, RAF709 demonstrated selective antitumor activity in tumor cells harboring BRAF or RAS mutations compared with cells with wild-type BRAF and RAS genes. RAF709 demonstrated a direct pharmacokinetic/pharmacodynamic relationship in in vivo tumor models harboring KRAS mutation. Furthermore, RAF709 elicited regression of primary human tumor-derived xenograft models with BRAF, NRAS, or KRAS mutations with excellent tolerability. Our results support further development of inhibitors like RAF709, which represents a next-generation RAF inhibitor with unique biochemical and cellular properties that enables antitumor activities in RAS-mutant tumors.Significance: In an effort to develop RAF inhibitors with the appropriate pharmacological properties to treat RAS mutant tumors, RAF709, a compound with potency, selectivity, and in vivo properties, was developed that will allow preclinical therapeutic hypothesis testing, but also provide an excellent probe to further unravel the complexities of RAF kinase signaling. Cancer Res; 78(6); 1537-48. ©2018 AACR.
Assuntos
2,2'-Dipiridil/análogos & derivados , Antineoplásicos/farmacologia , Benzamidas/farmacologia , Proteínas Proto-Oncogênicas B-raf/genética , Quinases raf/antagonistas & inibidores , Proteínas ras/genética , 2,2'-Dipiridil/farmacologia , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Feminino , Humanos , MAP Quinase Quinase Quinases/antagonistas & inibidores , Camundongos Nus , Mutação , Inibidores de Proteínas Quinases/farmacologia , Multimerização Proteica , Ensaios Antitumorais Modelo de Xenoenxerto , Quinases raf/metabolismoRESUMO
The Aurora kinases have been the subject of considerable interest as targets for the development of new anticancer agents. While evidence suggests inhibition of Aurora B kinase gives rise to the more pronounced antiproliferative phenotype, the most clinically advanced agents reported to date typically inhibit both Aurora A and B. We have discovered a series of pyrazoloquinazolines, some of which show greater than 1000-fold selectivity for Aurora B over Aurora A kinase activity, in recombinant enzyme assays. These compounds have been designed for parenteral administration and achieve high levels of solubility by virtue of their ability to be delivered as readily activated phosphate derivatives. The prodrugs are comprehensively converted to the des-phosphate form in vivo, and the active species have advantageous pharmacokinetic properties and safety pharmacology profiles. The compounds display striking in vivo activity, and compound 5 (AZD1152) has been selected for clinical evaluation and is currently in phase 1 clinical trials.
Assuntos
Antineoplásicos/síntese química , Organofosfatos/síntese química , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Pirazóis/síntese química , Quinazolinas/síntese química , Animais , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Aurora Quinase A , Aurora Quinase B , Aurora Quinases , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Inibidores das Enzimas do Citocromo P-450 , Ensaios de Seleção de Medicamentos Antitumorais , Canal de Potássio ERG1 , Canais de Potássio Éter-A-Go-Go/efeitos dos fármacos , Feminino , Histonas/metabolismo , Humanos , Masculino , Camundongos , Camundongos Nus , Organofosfatos/farmacocinética , Organofosfatos/farmacologia , Fosforilação , Pró-Fármacos/síntese química , Pró-Fármacos/farmacocinética , Pró-Fármacos/farmacologia , Ligação Proteica , Pirazóis/farmacocinética , Pirazóis/farmacologia , Quinazolinas/farmacocinética , Quinazolinas/farmacologia , Ratos , Proteínas Recombinantes/antagonistas & inibidores , Relação Estrutura-Atividade , Transplante HeterólogoRESUMO
The synthesis of a novel series of quinazolines substituted at C4 by five-membered ring aminoheterocycles is reported. Their in vitro structure-activity relationships versus Aurora A and B serine-threonine kinases is discussed. Our results demonstrate that quinazolines with a substituted aminothiazole at C4 possess potent Aurora A and B inhibitory activity and excellent selectivity against a panel of various serine-threonine and tyrosine kinases, as exemplified by compound 46. We found also that the position and nature of the substituent on the thiazole play key roles in cellular potency. Compounds with an acetanilide substituent at C5' have the greatest cellular activity. The importance of the C5' position for substitution has been rationalized by ab initio molecular orbital calculations. Results show that the planar conformation with the sulfur of the thiazole next to the quinazoline N-3 is strongly favored over the other possible planar conformation. Compound 46 is a potent suppressor of the expression of phospho-histone H3 in tumor cells in vitro as well as in vivo, where 46, administered as its phosphate prodrug 54, suppresses the expression of phospho-histone H3 in subcutaneously implanted tumors in nude mice.
Assuntos
Antineoplásicos/síntese química , Organofosfatos/síntese química , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Quinazolinas/síntese química , Tiazóis/síntese química , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Aurora Quinase A , Aurora Quinases , Linhagem Celular Tumoral , Histonas/antagonistas & inibidores , Histonas/biossíntese , Humanos , Camundongos , Camundongos Nus , Modelos Moleculares , Estrutura Molecular , Transplante de Neoplasias , Organofosfatos/química , Organofosfatos/farmacologia , Fosfoproteínas/antagonistas & inibidores , Fosfoproteínas/biossíntese , Pró-Fármacos/síntese química , Pró-Fármacos/química , Pró-Fármacos/farmacologia , Proteínas Serina-Treonina Quinases/química , Teoria Quântica , Quinazolinas/química , Quinazolinas/farmacologia , Relação Estrutura-Atividade , Tiazóis/química , Tiazóis/farmacologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Protein lysine methyltransferases (KMTs) have emerged as important regulators of epigenetic signaling. These enzymes catalyze the transfer of donor methyl groups from the cofactor S-adenosylmethionine to specific acceptor lysine residues on histones, leading to changes in chromatin structure and transcriptional regulation. These enzymes also methylate an array of nonhistone proteins, suggesting additional mechanisms by which they influence cellular physiology. SMYD2 is reported to be an oncogenic methyltransferase that represses the functional activity of the tumor suppressor proteins p53 and RB. HTS screening led to identification of five distinct substrate-competitive chemical series. Determination of liganded crystal structures of SMYD2 contributed significantly to "hit-to-lead" design efforts, culminating in the creation of potent and selective inhibitors that were used to understand the functional consequences of SMYD2 inhibition. Taken together, these results have broad implications for inhibitor design against KMTs and clearly demonstrate the potential for developing novel therapies against these enzymes.
Assuntos
Desenho de Fármacos , Inibidores Enzimáticos/farmacologia , Histona-Lisina N-Metiltransferase/antagonistas & inibidores , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Células HCT116 , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
The TMPRSS2:ERG gene fusion is common in androgen receptor (AR) positive prostate cancers, yet its function remains poorly understood. From a screen for functionally relevant ERG interactors, we identify the arginine methyltransferase PRMT5. ERG recruits PRMT5 to AR-target genes, where PRMT5 methylates AR on arginine 761. This attenuates AR recruitment and transcription of genes expressed in differentiated prostate epithelium. The AR-inhibitory function of PRMT5 is restricted to TMPRSS2:ERG-positive prostate cancer cells. Mutation of this methylation site on AR results in a transcriptionally hyperactive AR, suggesting that the proliferative effects of ERG and PRMT5 are mediated through attenuating AR's ability to induce genes normally involved in lineage differentiation. This provides a rationale for targeting PRMT5 in TMPRSS2:ERG positive prostate cancers. Moreover, methylation of AR at arginine 761 highlights a mechanism for how the ERG oncogene may coax AR towards inducing proliferation versus differentiation.
Assuntos
Células Epiteliais/metabolismo , Regulação Neoplásica da Expressão Gênica , Proteínas de Fusão Oncogênica/genética , Proteína-Arginina N-Metiltransferases/genética , Receptores Androgênicos/genética , Serina Endopeptidases/genética , Sequência de Bases , Diferenciação Celular , Linhagem Celular Tumoral , Proliferação de Células , Células Epiteliais/patologia , Humanos , Masculino , Metilação , Modelos Moleculares , Mutação , Proteínas de Fusão Oncogênica/metabolismo , Próstata/metabolismo , Próstata/patologia , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Multimerização Proteica , Estrutura Secundária de Proteína , Proteína-Arginina N-Metiltransferases/antagonistas & inibidores , Proteína-Arginina N-Metiltransferases/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Receptores Androgênicos/química , Receptores Androgênicos/metabolismo , Serina Endopeptidases/metabolismo , Transdução de Sinais , Regulador Transcricional ERG/genética , Regulador Transcricional ERG/metabolismoRESUMO
UNLABELLED: CRISPR/Cas9 has emerged as a powerful new tool to systematically probe gene function. We compared the performance of CRISPR to RNAi-based loss-of-function screens for the identification of cancer dependencies across multiple cancer cell lines. CRISPR dropout screens consistently identified more lethal genes than RNAi, implying that the identification of many cellular dependencies may require full gene inactivation. However, in two aneuploid cancer models, we found that all genes within highly amplified regions, including nonexpressed genes, scored as lethal by CRISPR, revealing an unanticipated class of false-positive hits. In addition, using a CRISPR tiling screen, we found that sgRNAs targeting essential domains generate the strongest lethality phenotypes and thus provide a strategy to rapidly define the protein domains required for cancer dependence. Collectively, these findings not only demonstrate the utility of CRISPR screens in the identification of cancer-essential genes, but also reveal the need to carefully control for false-positive results in chromosomally unstable cancer lines. SIGNIFICANCE: We show in this study that CRISPR-based screens have a significantly lower false-negative rate compared with RNAi-based screens, but have specific liabilities particularly in the interrogation of regions of genome amplification. Therefore, this study provides critical insights for applying CRISPR-based screens toward the systematic identification of new cancer targets. Cancer Discov; 6(8); 900-13. ©2016 AACR.See related commentary by Sheel and Xue, p. 824See related article by Aguirre et al., p. 914This article is highlighted in the In This Issue feature, p. 803.