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1.
Angew Chem Int Ed Engl ; 61(46): e202117276, 2022 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-36257909

RESUMO

Soellner published on the interplay between allosteric and adenosine triphosphate (ATP)-competitive inhibitors of ABL kinase, showing that the latter preferably binds to different conformational states of ABL compared to allosteric agents that specifically target the ABL myristate pocket (STAMP) and deducing that asciminib cannot bind to ABL simultaneously with ATP-competitive drugs. These results are to some extent in line with ours, although our analyses of dose-response matrices from combinations of asciminib with imatinib, nilotinib or dasatinib, show neither synergy nor antagonism, but suggest additive antiproliferative effects on BCR-ABL-dependent KCL22 cells. Furthermore, our X-ray crystallographic, solution nuclear magnetic resonance (NMR), and isothermal titration calorimetry studies show that asciminib can bind ABL concomitantly with type-1 or -2 ATP-competitive inhibitors to form ternary complexes. Concomitant binding of asciminib with imatinib, nilotinib, or dasatinib might translate to benefit some chronic myeloid leukaemia patients.


Assuntos
Antineoplásicos , Inibidores de Proteínas Quinases , Humanos , Mesilato de Imatinib/farmacologia , Dasatinibe/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/química , Proteínas Proto-Oncogênicas c-abl/química , Proteínas Proto-Oncogênicas c-abl/metabolismo , Trifosfato de Adenosina/metabolismo , Antineoplásicos/farmacologia , Proteínas de Fusão bcr-abl , Resistencia a Medicamentos Antineoplásicos
2.
Clin Cancer Res ; 27(1): 342-354, 2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-33046519

RESUMO

PURPOSE: SHP2 inhibitors offer an appealing and novel approach to inhibit receptor tyrosine kinase (RTK) signaling, which is the oncogenic driver in many tumors or is frequently feedback activated in response to targeted therapies including RTK inhibitors and MAPK inhibitors. We seek to evaluate the efficacy and synergistic mechanisms of combinations with a novel SHP2 inhibitor, TNO155, to inform their clinical development. EXPERIMENTAL DESIGN: The combinations of TNO155 with EGFR inhibitors (EGFRi), BRAFi, KRASG12Ci, CDK4/6i, and anti-programmed cell death-1 (PD-1) antibody were tested in appropriate cancer models in vitro and in vivo, and their effects on downstream signaling were examined. RESULTS: In EGFR-mutant lung cancer models, combination benefit of TNO155 and the EGFRi nazartinib was observed, coincident with sustained ERK inhibition. In BRAFV600E colorectal cancer models, TNO155 synergized with BRAF plus MEK inhibitors by blocking ERK feedback activation by different RTKs. In KRASG12C cancer cells, TNO155 effectively blocked the feedback activation of wild-type KRAS or other RAS isoforms induced by KRASG12Ci and greatly enhanced efficacy. In addition, TNO155 and the CDK4/6 inhibitor ribociclib showed combination benefit in a large panel of lung and colorectal cancer patient-derived xenografts, including those with KRAS mutations. Finally, TNO155 effectively inhibited RAS activation by colony-stimulating factor 1 receptor, which is critical for the maturation of immunosuppressive tumor-associated macrophages, and showed combination activity with anti-PD-1 antibody. CONCLUSIONS: Our findings suggest TNO155 is an effective agent for blocking both tumor-promoting and immune-suppressive RTK signaling in RTK- and MAPK-driven cancers and their tumor microenvironment. Our data provide the rationale for evaluating these combinations clinically.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Inibidores de Checkpoint Imunológico/farmacologia , Neoplasias/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Proteína Tirosina Fosfatase não Receptora Tipo 11/antagonistas & inibidores , Regulação Alostérica/efeitos dos fármacos , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Linhagem Celular Tumoral , Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Sinergismo Farmacológico , Receptores ErbB/antagonistas & inibidores , Feminino , Humanos , Inibidores de Checkpoint Imunológico/uso terapêutico , Camundongos , Mutação , Neoplasias/genética , Neoplasias/imunologia , Neoplasias/patologia , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas p21(ras)/antagonistas & inibidores , Proteínas Proto-Oncogênicas p21(ras)/genética , Macrófagos Associados a Tumor/efeitos dos fármacos , Macrófagos Associados a Tumor/imunologia , Ensaios Antitumorais Modelo de Xenoenxerto
3.
Cancer Res ; 80(19): 4278-4287, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32747364

RESUMO

Advanced ovarian cancers are a leading cause of cancer-related death in women and are currently treated with surgery and chemotherapy. This standard of care is often temporarily successful but exhibits a high rate of relapse, after which, treatment options are few. Here we investigate whether biomarker-guided use of multiple targeted therapies, including small molecules and antibody-drug conjugates, is a viable alternative. A panel of patient-derived ovarian cancer xenografts (PDX), similar in genetics and chemotherapy responsiveness to human tumors, was exposed to 21 monotherapies and combination therapies. Three monotherapies and one combination were found to be active in different subsets of PDX. Analysis of gene expression data identified biomarkers associated with responsiveness to each of the three targeted therapies, none of which directly inhibits an oncogenic driver. While no single treatment had as high a response rate as chemotherapy, nearly 90% of PDXs were eligible for and responded to at least one biomarker-guided treatment, including tumors resistant to standard chemotherapy. The distribution of biomarker positivity in The Cancer Genome Atlas data suggests the potential for a similar precision approach in human patients. SIGNIFICANCE: This study exploits a panel of patient-derived xenografts to demonstrate that most ovarian tumors can be matched to effective biomarker-guided treatments.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Biomarcadores Tumorais/genética , Neoplasias Ovarianas/tratamento farmacológico , Ensaios Antitumorais Modelo de Xenoenxerto/métodos , Antineoplásicos/farmacologia , Carcinoma Epitelial do Ovário/tratamento farmacológico , Carcinoma Epitelial do Ovário/genética , Carcinoma Epitelial do Ovário/mortalidade , Carcinoma Epitelial do Ovário/patologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Estimativa de Kaplan-Meier , Terapia de Alvo Molecular/métodos , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/mortalidade , Neoplasias Ovarianas/patologia , Medicina de Precisão , Estudo de Prova de Conceito
4.
Sci Adv ; 6(25): eabb2210, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32704543

RESUMO

Inhibitors of cyclin-dependent kinases CDK4 and CDK6 have been approved for treatment of hormone receptor-positive breast cancers. In contrast, triple-negative breast cancers (TNBCs) are resistant to CDK4/6 inhibition. Here, we demonstrate that a subset of TNBC critically requires CDK4/6 for proliferation, and yet, these TNBC are resistant to CDK4/6 inhibition due to sequestration of CDK4/6 inhibitors into tumor cell lysosomes. This sequestration is caused by enhanced lysosomal biogenesis and increased lysosomal numbers in TNBC cells. We developed new CDK4/6 inhibitor compounds that evade the lysosomal sequestration and are efficacious against resistant TNBC. We also show that coadministration of lysosomotropic or lysosome-destabilizing compounds (an antibiotic azithromycin, an antidepressant siramesine, an antimalaria compound chloroquine) renders resistant tumor cells sensitive to currently used CDK4/6 inhibitors. Lastly, coinhibition of CDK2 arrested proliferation of CDK4/6 inhibitor-resistant cells. These observations may extend the use of CDK4/6 inhibitors to TNBCs that are refractory to current anti-CDK4/6 therapies.

6.
Oncotarget ; 11(4): 443-451, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-32064048

RESUMO

There is a compelling need for new therapeutic strategies for glioblastoma multiforme (GBM). Preclinical target and therapeutic discovery for GBMs is primarily conducted using cell lines grown in serum-containing media, such as U-87 MG, which do not reflect the gene expression profiles of tumors found in GBM patients. To address this lack of representative models, we sought to develop a panel of patient-derived GBM models and characterize their genomic features, using RNA sequencing (RNA-seq) and growth characteristics, both when grown as neurospheres in culture, and grown orthotopically as xenografts in mice. When we compared these with commonly used GBM cell lines in the Cancer Cell Line Encyclopedia (CCLE), we found these patient-derived models to have greater diversity in gene expression and to better correspond to GBMs directly sequenced from patient tumor samples. We also evaluated the potential of these models for targeted therapy, by using the genomic characterization to identify small molecules that inhibit the growth of distinct subsets of GBMs, paving the way for precision medicines for GBM.

7.
Oncotarget ; 9(81): 35226-35240, 2018 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-30443290

RESUMO

Inhibition of cyclin-dependent kinases 4 and 6 (CDK4/6) is associated with robust antitumor activity. Ribociclib (LEE011) is an orally bioavailable CDK4/6 inhibitor that is approved for the treatment of hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer, in combination with an aromatase inhibitor, and is currently being evaluated in several additional trials. Here, we report the preclinical profile of ribociclib. When tested across a large panel of kinase active site binding assays, ribociclib and palbociclib were highly selective for CDK4, while abemaciclib showed affinity to several other kinases. Both ribociclib and abemaciclib showed slightly higher potency in CDK4-dependent cells than in CDK6-dependent cells, while palbociclib did not show such a difference. Profiling CDK4/6 inhibitors in large-scale cancer cell line screens in vitro confirmed that RB1 loss of function is a negative predictor of sensitivity. We also found that routinely used cellular viability assays measuring adenosine triphosphate levels as a proxy for cell numbers underestimated the effects of CDK4/6 inhibition, which contrasts with assays that assess cell number more directly. Robust antitumor efficacy and combination benefit was detected when ribociclib was added to encorafenib, nazartinib, or endocrine therapies in patient-derived xenografts.

8.
J Med Chem ; 61(18): 8120-8135, 2018 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-30137981

RESUMO

Chronic myelogenous leukemia (CML) arises from the constitutive activity of the BCR-ABL1 oncoprotein. Tyrosine kinase inhibitors (TKIs) that target the ATP-binding site have transformed CML into a chronic manageable disease. However, some patients develop drug resistance due to ATP-site mutations impeding drug binding. We describe the discovery of asciminib (ABL001), the first allosteric BCR-ABL1 inhibitor to reach the clinic. Asciminib binds to the myristate pocket of BCR-ABL1 and maintains activity against TKI-resistant ATP-site mutations. Although resistance can emerge due to myristate-site mutations, these are sensitive to ATP-competitive inhibitors so that combinations of asciminib with ATP-competitive TKIs suppress the emergence of resistance. Fragment-based screening using NMR and X-ray yielded ligands for the myristate pocket. An NMR-based conformational assay guided the transformation of these inactive ligands into ABL1 inhibitors. Further structure-based optimization for potency, physicochemical, pharmacokinetic, and drug-like properties, culminated in asciminib, which is currently undergoing clinical studies in CML patients.


Assuntos
Descoberta de Drogas , Proteínas de Fusão bcr-abl/antagonistas & inibidores , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Niacinamida/análogos & derivados , Inibidores de Proteínas Quinases/farmacologia , Pirazóis/farmacologia , Regulação Alostérica , Animais , Cães , Proteínas de Fusão bcr-abl/genética , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/enzimologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Masculino , Camundongos , Modelos Moleculares , Estrutura Molecular , Mutação , Niacinamida/química , Niacinamida/farmacologia , Fosforilação , Conformação Proteica , Inibidores de Proteínas Quinases/química , Pirazóis/química , Ratos , Ratos Sprague-Dawley , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
9.
Nature ; 543(7647): 733-737, 2017 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-28329763

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 Xenoenxerto
10.
J Med Chem ; 60(7): 2790-2818, 2017 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-28296398

RESUMO

Tetrahydroisoquinoline 40 has been identified as a potent ERα antagonist and selective estrogen receptor degrader (SERD), exhibiting good oral bioavailability, antitumor efficacy, and SERD activity in vivo. We outline the discovery and chemical optimization of the THIQ scaffold leading to THIQ 40 and showcase the racemization of the scaffold, pharmacokinetic studies in preclinical species, and the in vivo efficacy of THIQ 40 in a MCF-7 human breast cancer xenograft model.


Assuntos
Antineoplásicos/química , Antineoplásicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Mama/efeitos dos fármacos , Receptor alfa de Estrogênio/antagonistas & inibidores , Tetra-Hidroisoquinolinas/química , Tetra-Hidroisoquinolinas/uso terapêutico , Acrilatos/química , Acrilatos/farmacocinética , Acrilatos/farmacologia , Acrilatos/uso terapêutico , Administração Oral , Animais , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Mama/metabolismo , Mama/patologia , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Cães , Descoberta de Drogas , Receptor alfa de Estrogênio/metabolismo , Feminino , Humanos , Células MCF-7 , Camundongos Endogâmicos C57BL , Simulação de Acoplamento Molecular , Proteólise/efeitos dos fármacos , Tetra-Hidroisoquinolinas/farmacocinética , Tetra-Hidroisoquinolinas/farmacologia
11.
Nat Med ; 21(11): 1318-25, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26479923

RESUMO

Profiling candidate therapeutics with limited cancer models during preclinical development hinders predictions of clinical efficacy and identifying factors that underlie heterogeneous patient responses for patient-selection strategies. We established ∼1,000 patient-derived tumor xenograft models (PDXs) with a diverse set of driver mutations. With these PDXs, we performed in vivo compound screens using a 1 × 1 × 1 experimental design (PDX clinical trial or PCT) to assess the population responses to 62 treatments across six indications. We demonstrate both the reproducibility and the clinical translatability of this approach by identifying associations between a genotype and drug response, and established mechanisms of resistance. In addition, our results suggest that PCTs may represent a more accurate approach than cell line models for assessing the clinical potential of some therapeutic modalities. We therefore propose that this experimental paradigm could potentially improve preclinical evaluation of treatment modalities and enhance our ability to predict clinical trial responses.


Assuntos
Antineoplásicos/uso terapêutico , Ensaios de Triagem em Larga Escala/métodos , Neoplasias/tratamento farmacológico , Ensaios Antitumorais Modelo de Xenoenxerto/métodos , Animais , Neoplasias da Mama/tratamento farmacológico , Carcinoma/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Ductal Pancreático/tratamento farmacológico , Neoplasias Colorretais/tratamento farmacológico , Modelos Animais de Doenças , Feminino , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Melanoma/tratamento farmacológico , Camundongos , Transplante de Neoplasias , Neoplasias Pancreáticas/tratamento farmacológico , Reprodutibilidade dos Testes , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Gástricas/tratamento farmacológico
12.
Mol Cancer Ther ; 13(9): 2184-93, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25028469

RESUMO

Well-differentiated/dedifferentiated liposarcomas (WD/DDLPS) are among the most common subtypes of soft tissue sarcomas. Conventional systemic chemotherapy has limited efficacy and novel therapeutic strategies are needed to achieve better outcomes for patients. The cyclin-dependent kinase 4 (CDK4) gene is highly amplified in more than 95% of WD/DDLPS. In this study, we explored the role of CDK4 and the effects of NVP-LEE011 (LEE011), a novel selective inhibitor of CDK4/CDK6, on a panel of human liposarcoma cell lines and primary tumor xenografts. We found that both CDK4 knockdown by siRNA and inhibition by LEE011 diminished retinoblastoma (RB) phosphorylation and dramatically decreased liposarcoma cell growth. Cell-cycle analysis demonstrated arrest at G0-G1. siRNA-mediated knockdown of RB rescued the inhibitory effects of LEE011, demonstrating that LEE011 decreased proliferation through RB. Oral administration of LEE011 to mice bearing human liposarcoma xenografts resulted in approximately 50% reduction in tumor (18)F-fluorodeoxyglucose uptake with decreased tumor biomarkers, including RB phosphorylation and bromodeoxyuridine incorporation in vivo. Continued treatment inhibited tumor growth or induced regression without detrimental effects on mouse weight. After prolonged continuous dosing, reestablishment of RB phosphorylation and cell-cycle progression was noted. These findings validate the critical role of CDK4 in maintaining liposarcoma proliferation through its ability to inactivate RB function, and suggest its potential function in the regulation of survival and metabolism of liposarcoma, supporting the rationale for clinical development of LEE011 for the treatment of WD/DDLPS.


Assuntos
Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Lipossarcoma/tratamento farmacológico , Administração Oral , Animais , Peso Corporal , Ciclo Celular , Diferenciação Celular , Linhagem Celular Tumoral , Proliferação de Células , Células Cultivadas , Feminino , Dosagem de Genes , Humanos , Imuno-Histoquímica , Lipossarcoma/metabolismo , Masculino , Camundongos , Camundongos Nus , Transplante de Neoplasias , Fosforilação , RNA Interferente Pequeno/metabolismo , Proteína do Retinoblastoma/metabolismo
13.
Oncotarget ; 4(6): 816-29, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23615731

RESUMO

The molecular chaperone heat shock protein 90 (HSP90) facilitates the appropriate folding of various oncogenic proteins and is necessary for the survival of some cancer cells. HSP90 is therefore an attractive drug target, but the efficacy of HSP90 inhibitor may be limited by HSP90 inhibition induced feedback mechanisms. Through pooled RNA interference screens, we identified that heat shock factor 1(HSF1) is a sensitizer of HSP90 inhibitor. A striking combinational effect was observed when HSF1 knockdown plus with HSP90 inhibitors treatment in various cancer cell lines and tumor mouse models. Interestingly, HSF1 is highly expressed in hepatocellular carcinoma (HCC) patient samples and HCC is sensitive to combinational treatment, indicating a potential indication for the combinational treatment. To understand the mechanism of the combinational effect, we identified that a HSF1-target gene DEDD2 is involved in attenuating the effect of HSP90 inhibitors. Thus, the transcriptional activities of HSF1 induced by HSP90 inhibitors provide a feedback mechanism of limiting the HSP90 inhibitor's activity, and targeting HSF1 may provide a new avenue to enhance HSP90 inhibitors activity in human cancers.


Assuntos
Carcinoma Hepatocelular/terapia , Proteínas de Ligação a DNA/genética , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Proteínas de Choque Térmico HSP90/metabolismo , Neoplasias Hepáticas/terapia , Fatores de Transcrição/genética , Animais , Apoptose/fisiologia , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/genética , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/metabolismo , Proteínas Adaptadoras de Sinalização de Receptores de Domínio de Morte/genética , Doxiciclina/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Técnicas de Silenciamento de Genes , Células HCT116 , Proteínas de Choque Térmico HSP90/genética , Fatores de Transcrição de Choque Térmico , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/genética , Camundongos , Terapia de Alvo Molecular , Proteínas Nucleares/genética , RNA Interferente Pequeno/genética , Fatores de Transcrição/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
15.
ACS Med Chem Lett ; 3(6): 445-9, 2012 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-24900493

RESUMO

Herein, we describe the discovery of potent and highly selective inhibitors of both CDK4 and CDK6 via structure-guided optimization of a fragment-based screening hit. CDK6 X-ray crystallography and pharmacokinetic data steered efforts in identifying compound 6, which showed >1000-fold selectivity for CDK4 over CDKs 1 and 2 in an enzymatic assay. Furthermore, 6 demonstrated in vivo inhibition of pRb-phosphorylation and oral efficacy in a Jeko-1 mouse xenograft model.

16.
Proc Natl Acad Sci U S A ; 108(41): 17135-40, 2011 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-21949247

RESUMO

Persistent expression of certain oncogenes is required for tumor maintenance. This phenotype is referred to as oncogene addiction and has been clinically validated by anticancer therapies that specifically inhibit oncoproteins such as BCR-ABL, c-Kit, HER2, PDGFR, and EGFR. Identifying additional genes that are required for tumor maintenance may lead to new targets for anticancer drugs. Although the role of aberrant Wnt pathway activation in the initiation of colorectal cancer has been clearly established, it remains unclear whether sustained Wnt pathway activation is required for colorectal tumor maintenance. To address this question, we used inducible ß-catenin shRNAs to temporally control Wnt pathway activation in vivo. Here, we show that active Wnt/ß-catenin signaling is required for maintenance of colorectal tumor xenografts harboring APC mutations. Reduced tumor growth upon ß-catenin inhibition was due to cell cycle arrest and differentiation. Upon reactivation of the Wnt/ß-catenin pathway colorectal cancer cells resumed proliferation and reacquired a crypt progenitor phenotype. In human colonic adenocarcinomas, high levels of nuclear ß-catenin correlated with crypt progenitor but not differentiation markers, suggesting that the Wnt/ß-catenin pathway may also control colorectal tumor cell fate during the maintenance phase of tumors in patients. These results support efforts to treat human colorectal cancer by pharmacological inhibition of the Wnt/ß-catenin pathway.


Assuntos
Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Genes APC , Mutação , Via de Sinalização Wnt , beta Catenina/metabolismo , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Animais , Ciclo Celular , Diferenciação Celular , Linhagem Celular Tumoral , Neoplasias Colorretais/patologia , Humanos , Camundongos , Camundongos Nus , Transplante de Neoplasias , RNA Interferente Pequeno/genética , Transdução de Sinais , Transplante Heterólogo , beta Catenina/antagonistas & inibidores , beta Catenina/genética
17.
Cancer Res ; 71(7): 2643-53, 2011 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-21324920

RESUMO

The activated B-cell-like (ABC) subtype of diffuse large B-cell lymphoma (DLBCL) correlates with poor prognosis. The ABC subtype of DLBCL is associated with constitutive activation of the NF-κB pathway, and oncogenic lesions have been identified in its regulators, including CARD11/CARMA1 (caspase recruitment domain-containing protein 11), A20/TNFAIP3, and CD79A/B. In this study, we offer evidence of therapeutic potential for the selective PKC (protein kinase C) inhibitor sotrastaurin (STN) in preclinical models of DLBCL. A significant fraction of ABC DLBCL cell lines exhibited strong sensitivity to STN, and we found that the molecular nature of NF-κB pathway lesions predicted responsiveness. CD79A/B mutations correlated with STN sensitivity, whereas CARD11 mutations rendered ABC DLBCL cell lines insensitive. Growth inhibitory effects of PKC inhibition correlated with NF-κB pathway inhibition and were mediated by induction of G1-phase cell-cycle arrest and/or cell death. We found that STN produced significant antitumor effects in a mouse xenograft model of CD79A/B-mutated DLBCL. Collectively, our findings offer a strong rationale for the clinical evaluation of STN in ABC DLBCL patients who harbor CD79 mutations also illustrating the necessity to stratify DLBCL patients according to their genetic abnormalities.


Assuntos
Antígenos CD79/genética , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Pirróis/farmacologia , Quinazolinas/farmacologia , Animais , Proteínas Adaptadoras de Sinalização CARD/genética , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Processos de Crescimento Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Fase G1/efeitos dos fármacos , Guanilato Ciclase/genética , Guanilato Ciclase/metabolismo , Humanos , Linfoma Difuso de Grandes Células B/enzimologia , Camundongos , Mutação , NF-kappa B/metabolismo , Proteína Quinase C/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-bcr/metabolismo , Transdução de Sinais/efeitos dos fármacos
18.
Cancer Res ; 70(13): 5528-38, 2010 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-20530672

RESUMO

Bmi-1 is a member of the Polycomb group family of proteins that function in the epigenetic silencing of genes governing self-renewal, differentiation, and proliferation. Bmi-1 was first identified through its ability to accelerate c-Myc-induced lymphomagenesis. Subsequent studies have further supported an oncogenic role for Bmi-1 in several cancers including those of the breast, lung, prostate, and brain. Using a stable and inducible shRNA system to silence Bmi-1 gene expression, we show a novel role for Bmi-1 in regulating the growth and clonogenic capacity of multiple myeloma cells both in vitro and in vivo. Moreover, to elucidate novel gene targets controlled by Bmi-1, global transcriptional profiling studies were performed in the setting of induced loss of Bmi-1 function. We found that the expression of the proapoptotic gene Bim is negatively regulated by Bmi-1 and that Bim knockdown functionally rescues the apoptotic phenotype induced upon loss of Bmi-1. Therefore, these studies not only highlight Bmi-1 as a cancer-dependent factor in multiple myeloma, but also elucidate a novel antiapoptotic mechanism for Bmi-1 function involving the suppression of Bim.


Assuntos
Mieloma Múltiplo/patologia , Proteínas Nucleares/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Repressoras/metabolismo , Animais , Apoptose/genética , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Proteína 11 Semelhante a Bcl-2 , Processos de Crescimento Celular/genética , Linhagem Celular Tumoral , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Mieloma Múltiplo/genética , Mieloma Múltiplo/metabolismo , Proteínas Nucleares/genética , Complexo Repressor Polycomb 1 , Proteínas Proto-Oncogênicas/genética , Proteínas Repressoras/genética , Transcrição Gênica
19.
Nature ; 463(7283): 899-905, 2010 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-20164920

RESUMO

A powerful way to discover key genes with causal roles in oncogenesis is to identify genomic regions that undergo frequent alteration in human cancers. Here we present high-resolution analyses of somatic copy-number alterations (SCNAs) from 3,131 cancer specimens, belonging largely to 26 histological types. We identify 158 regions of focal SCNA that are altered at significant frequency across several cancer types, of which 122 cannot be explained by the presence of a known cancer target gene located within these regions. Several gene families are enriched among these regions of focal SCNA, including the BCL2 family of apoptosis regulators and the NF-kappaBeta pathway. We show that cancer cells containing amplifications surrounding the MCL1 and BCL2L1 anti-apoptotic genes depend on the expression of these genes for survival. Finally, we demonstrate that a large majority of SCNAs identified in individual cancer types are present in several cancer types.


Assuntos
Variações do Número de Cópias de DNA/genética , Dosagem de Genes/genética , Neoplasias/genética , Apoptose/genética , Linhagem Celular Tumoral , Sobrevivência Celular/genética , Amplificação de Genes/genética , Genômica , Humanos , Família Multigênica/genética , Proteína de Sequência 1 de Leucemia de Células Mieloides , Neoplasias/classificação , Neoplasias/patologia , Proteínas Proto-Oncogênicas c-bcl-2/genética , Transdução de Sinais , Proteína bcl-X/genética
20.
Cancer Res ; 69(10): 4286-93, 2009 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-19401449

RESUMO

The RAS pathway is one of the most frequently deregulated pathways in cancer. RAS signals through multiple effector pathways, including the RAF/mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) kinase (MEK)/ERK MAPK and phosphatidylinositol 3-kinase (PI3K)-AKT signaling cascades. The oncogenic potential of these effector pathways is illustrated by the frequent occurrence of activating mutations in BRAF and PIK3CA as well as loss-of-function mutations in the tumor suppressor PTEN, a negative regulator of PI3K. Previous studies have found that whereas BRAF mutant cancers are highly sensitive to MEK inhibition, RAS mutant cancers exhibit a more variable response. The molecular mechanisms responsible for this heterogeneous response remain unclear. In this study, we show that PI3K pathway activation strongly influences the sensitivity of RAS mutant cells to MEK inhibitors. Activating mutations in PIK3CA reduce the sensitivity to MEK inhibition, whereas PTEN mutations seem to cause complete resistance. We further show that down-regulation of PIK3CA resensitizes cells with co-occurring KRAS and PIK3CA mutations to MEK inhibition. At the molecular level, the dual inhibition of both pathways seems to be required for complete inhibition of the downstream mammalian target of rapamycin effector pathway and results in the induction of cell death. Finally, we show that whereas inactivation of either the MEK or PI3K pathway leads to partial tumor growth inhibition, targeted inhibition of both pathways is required to achieve tumor stasis. Our study provides molecular insights that help explain the heterogeneous response of KRAS mutant cancers to MEK pathway inhibition and presents a strong rationale for the clinical testing of combination MEK and PI3K targeted therapies.


Assuntos
Benzamidas/toxicidade , Difenilamina/análogos & derivados , Doxiciclina/toxicidade , Genes ras/genética , Mutação , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Animais , Antineoplásicos/toxicidade , Apoptose/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Neoplasias do Colo/enzimologia , Neoplasias do Colo/genética , Difenilamina/toxicidade , Ativação Enzimática , Feminino , Células HCT116 , Humanos , Camundongos , Camundongos Nus , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transplante Heterólogo
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