RESUMO
BRAF(V600E) mutant melanomas treated with inhibitors of the BRAF and MEK kinases almost invariably develop resistance that is frequently caused by reactivation of the mitogen activated protein kinase (MAPK) pathway. To identify novel treatment options for such patients, we searched for acquired vulnerabilities of MAPK inhibitor-resistant melanomas. We find that resistance to BRAF+MEK inhibitors is associated with increased levels of reactive oxygen species (ROS). Subsequent treatment with the histone deacetylase inhibitor vorinostat suppresses SLC7A11, leading to a lethal increase in the already-elevated levels of ROS in drug-resistant cells. This causes selective apoptotic death of only the drug-resistant tumor cells. Consistently, treatment of BRAF inhibitor-resistant melanoma with vorinostat in mice results in dramatic tumor regression. In a study in patients with advanced BRAF+MEK inhibitor-resistant melanoma, we find that vorinostat can selectively ablate drug-resistant tumor cells, providing clinical proof of concept for the novel therapy identified here.
Assuntos
Resistencia a Medicamentos Antineoplásicos , Melanoma/tratamento farmacológico , Neoplasias Cutâneas/tratamento farmacológico , Sistema y+ de Transporte de Aminoácidos/metabolismo , Animais , Apoptose , Linhagem Celular Tumoral , Proliferação de Células , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Inibidores de Histona Desacetilases/farmacologia , Humanos , MAP Quinase Quinase 1/metabolismo , Sistema de Sinalização das MAP Quinases , Melanoma/genética , Camundongos , Mutação , Transplante de Neoplasias , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas B-raf/genética , Espécies Reativas de Oxigênio/metabolismo , Neoplasias Cutâneas/genética , Resultado do Tratamento , Vorinostat/farmacologiaRESUMO
Tumor heterogeneity can create a unique symbiotic tumor microenvironment. Earlier, we showed that clonal evolution in mouse small cell lung cancer (SCLC) can result in subclones that, upon cografting, endow the neuroendocrine tumor cells with metastatic potential. We now show that paracrine signaling between SCLC subclones is a critical requirement in the early steps of the metastatic process, such as local invasion and intravasation. We further show evidence that paracrine signaling via fibroblast growth factor 2 (Fgf2) and Mapk between these diverged tumor subclones causes enhanced expression of the Pea3 (polyomavirus enhancer activator 3) transcription factor, resulting in metastatic dissemination of the neuroendocrine tumor subclones. Our data reveal for the first time paracrine signaling between tumor cell subclones in SCLC that results in metastatic spread of SCLC.
Assuntos
Regulação Neoplásica da Expressão Gênica , Metástase Neoplásica/fisiopatologia , Comunicação Parácrina/fisiologia , Carcinoma de Pequenas Células do Pulmão/fisiopatologia , Fatores de Transcrição/metabolismo , Animais , Linhagem Celular Tumoral , Meios de Cultivo Condicionados , Fator 2 de Crescimento de Fibroblastos/metabolismo , Regulação Neoplásica da Expressão Gênica/genética , Técnicas de Silenciamento de Genes , Camundongos , Camundongos Endogâmicos BALB C , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Invasividade Neoplásica/genética , Metástase Neoplásica/genética , Proteínas Proto-Oncogênicas c-ets/genética , Proteínas Proto-Oncogênicas c-ets/metabolismo , Fatores de Transcrição/genéticaRESUMO
Since its discovery in the early 1990s the deleted in colorectal cancer (DCC) gene, located on chromosome 18q21, has been proposed as a tumour suppressor gene as its loss is implicated in the majority of advanced colorectal and many other cancers. DCC belongs to the family of netrin 1 receptors, which function as dependence receptors as they control survival or apoptosis depending on ligand binding. However, the role of DCC as a tumour suppressor remains controversial because of the rarity of DCC-specific mutations and the presence of other tumour suppressor genes in the same chromosomal region. Here we show that in a mouse model of mammary carcinoma based on somatic inactivation of p53, additional loss of DCC promotes metastasis formation without affecting the primary tumour phenotype. Furthermore, we demonstrate that in cell cultures derived from p53-deficient mouse mammary tumours DCC expression controls netrin-1-dependent cell survival, providing a mechanistic basis for the enhanced metastatic capacity of tumour cells lacking DCC. Consistent with this idea, in vivo tumour-cell survival is enhanced by DCC loss. Together, our data support the function of DCC as a context-dependent tumour suppressor that limits survival of disseminated tumour cells.
Assuntos
Genes p53/genética , Neoplasias Mamárias Experimentais/genética , Neoplasias Mamárias Experimentais/patologia , Metástase Neoplásica/genética , Metástase Neoplásica/patologia , Receptores de Superfície Celular/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Animais , Apoptose/genética , Linhagem Celular Tumoral , Sobrevivência Celular/genética , Receptor DCC , Modelos Animais de Doenças , Feminino , Neoplasias Mamárias Experimentais/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fatores de Crescimento Neural/deficiência , Fatores de Crescimento Neural/genética , Fatores de Crescimento Neural/metabolismo , Netrina-1 , Receptores de Superfície Celular/deficiência , Receptores de Superfície Celular/genética , Proteínas Supressoras de Tumor/deficiência , Proteínas Supressoras de Tumor/genéticaRESUMO
Much controversy surrounds the cell-of-origin of mutant K-Ras (K-RasG12D)-induced lung adenocarcinoma. To shed light on this issue, we have used technology that enables us to conditionally target K-RasG12D expression in Surfactant Protein C (SPC)(+) alveolar type 2 cells and in Clara cell antigen 10 (CC10)(+) Clara cells by use of cell-type-restricted recombinant Adeno-Cre viruses. Experiments were performed both in the presence and absence of the tumor suppressor gene p53, enabling us to assess what effect the cell-of-origin and the introduced genetic lesions have on the phenotypic characteristics of the resulting adenocarcinomas. We conclude that both SPC-expressing alveolar type 2 cells and CC10-expressing Clara cells have the ability to initiate malignant transformation following the introduction of these genetic alterations. The lungs of K-Ras(lox-Stop-lox-G12D/+) and K-Ras(lox-Stop-lox-G12D/+);tumor suppressor gene Trp53(F/F) mice infected with Adeno5-SPC-Cre and Adeno5-CC10-Cre viruses displayed differences in their tumor spectrum, indicating distinct cellular routes of tumor initiation. Moreover, using a multicolor Cre reporter line, we demonstrate that the resulting tumors arise from a clonal expansion of switched cells. Taken together, these results indicate that there are multiple cellular paths to K-RasG12D-induced adenocarcinoma and that the initiating cell influences the histopathological phenotype of the tumors that arise.
Assuntos
Adenocarcinoma/genética , Adenocarcinoma/patologia , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Mutação/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Adenocarcinoma de Pulmão , Adenoviridae/metabolismo , Animais , Proliferação de Células , Células Clonais , Progressão da Doença , Vetores Genéticos , Imuno-Histoquímica , Integrases/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Modelos Biológicos , Proteínas Mutantes/metabolismo , Lesões Pré-Cancerosas/patologia , Recombinação Genética/genética , Proteína Supressora de Tumor p53/metabolismo , Uteroglobina/metabolismoRESUMO
Metastasis confronts clinicians with two major challenges: estimating the patient's risk of metastasis and identifying therapeutic targets. Because they are key signal integrators connecting cellular processes to clinical outcome, we aimed to identify transcriptional nodes regulating cancer cell metastasis. Using rodent xenograft models that we previously developed, we identified the transcription factor Fos-related antigen-1 (Fra-1) as a key coordinator of metastasis. Because Fra-1 often is overexpressed in human metastatic breast cancers and has been shown to control their invasive potential in vitro, we aimed to assess the implication and prognostic significance of the Fra-1-dependent genetic program in breast cancer metastasis and to identify potential Fra-1-dependent therapeutic targets. In several in vivo assays in mice, we demonstrate that stable RNAi depletion of Fra-1 from human breast cancer cells strongly suppresses their ability to metastasize. These results support a clinically important role for Fra-1 and the genetic program it controls. We show that a Fra-1-dependent gene-expression signature accurately predicts recurrence of breast cancer. Furthermore, a synthetic lethal drug screen revealed that antagonists of the adenosine receptor A2B (ADORA2B) are preferentially toxic to breast tumor cells expressing Fra-1. Both RNAi silencing and pharmacologic blockade of ADORA2B inhibited filopodia formation and invasive activity of breast cancer cells and correspondingly reduced tumor outgrowth in the lungs. These data show that Fra-1 activity is causally involved in and is a prognostic indicator of breast cancer metastasis. They suggest that Fra-1 activity predicts responsiveness to inhibition of pharmacologically tractable targets, such as ADORA2B, which may be used for clinical interference of metastatic breast cancer.
Assuntos
Neoplasias da Mama/metabolismo , Regulação Neoplásica da Expressão Gênica , Proteínas Proto-Oncogênicas c-fos/metabolismo , Receptor A2B de Adenosina/metabolismo , Antagonistas do Receptor A2 de Adenosina/farmacologia , Animais , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Invasividade Neoplásica , Metástase Neoplásica , Transplante de Neoplasias , Proteínas Proto-Oncogênicas c-fos/genética , Pseudópodes/genética , Pseudópodes/metabolismo , Pseudópodes/patologia , Ratos , Receptor A2B de Adenosina/genética , Transplante Heterólogo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The Polycomb group and oncogene Bmi1 is required for the proliferation of various differentiated cells and for the self-renewal of stem cells and leukemic cancer stem cells. Repression of the Ink4a/Arf locus is a well described mechanism through which Bmi1 can exert its proliferative effects. However, we now demonstrate in an orthotopic transplantation model for glioma, a type of cancer harboring cancer stem cells, that Bmi1 is also required for tumor development in an Ink4a/Arf-independent manner. Tumors derived from Bmi1;Ink4a/Arf doubly deficient astrocytes or neural stem cells have a later time of onset and different histological grading. Moreover, in the absence of Ink4a/Arf, Bmi1-deficient cells and tumors display changes in differentiation capacity.
Assuntos
Astrócitos/metabolismo , Neoplasias Encefálicas/metabolismo , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Glioblastoma/metabolismo , Neurônios/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Repressoras/metabolismo , Transdução de Sinais , Células-Tronco/metabolismo , Células 3T3 , Animais , Astrócitos/patologia , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Diferenciação Celular , Proliferação de Células , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Células Cultivadas , Inibidor p16 de Quinase Dependente de Ciclina/deficiência , Inibidor p16 de Quinase Dependente de Ciclina/genética , Receptores ErbB/genética , Receptores ErbB/metabolismo , Regulação Neoplásica da Expressão Gênica , Glioblastoma/genética , Glioblastoma/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Camundongos Nus , Mutação , Estadiamento de Neoplasias , Neoplasias Experimentais/metabolismo , Neoplasias Experimentais/patologia , Neurônios/patologia , Proteínas Nucleares/deficiência , Proteínas Nucleares/genética , Fenótipo , Complexo Repressor Polycomb 1 , Proteínas Proto-Oncogênicas/deficiência , Proteínas Proto-Oncogênicas/genética , Proteínas Repressoras/genética , Transdução de Sinais/genética , Células-Tronco/patologia , Fatores de Tempo , Transdução GenéticaRESUMO
Metastatic disease is the primary cause of death in breast cancer, the most common malignancy in Western women. Loss of E-cadherin is associated with tumor metastasis, as well as with invasive lobular carcinoma (ILC), which accounts for 10%-15% of all breast cancers. To study the role of E-cadherin in breast oncogenesis, we have introduced conditional E-cadherin mutations into a mouse tumor model based on epithelium-specific knockout of p53. Combined loss of E-cadherin and p53 resulted in accelerated development of invasive and metastatic mammary carcinomas, which show strong resemblance to human ILC. Moreover, loss of E-cadherin induced anoikis resistance and facilitated angiogenesis, thus promoting metastatic disease. Our results suggest that loss of E-cadherin contributes to both mammary tumor initiation and metastasis.
Assuntos
Anoikis/fisiologia , Neoplasias da Mama/metabolismo , Caderinas/metabolismo , Carcinoma Lobular/metabolismo , Inativação Gênica , Proteína Supressora de Tumor p53/metabolismo , Animais , Neoplasias da Mama/patologia , Neoplasias da Mama/fisiopatologia , Caderinas/genética , Carcinoma Lobular/patologia , Carcinoma Lobular/fisiopatologia , Modelos Animais de Doenças , Feminino , Humanos , Glândulas Mamárias Humanas/anatomia & histologia , Glândulas Mamárias Humanas/metabolismo , Glândulas Mamárias Humanas/patologia , Camundongos , Camundongos Endogâmicos BALB C , Metástase Neoplásica , Neovascularização Patológica , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Taxa de Sobrevida , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/genéticaRESUMO
Mutations in the serine-threonine kinase (LKB1) lead to a gastrointestinal hamartomatous polyposis disorder with increased predisposition to cancer (Peutz-Jeghers syndrome). LKB1 has many targets, including the AMP-activated protein kinase (AMPK) that is phosphorylated under low-energy conditions. AMPK phosphorylation in turn, affects several processes, including inhibition of the target of rapamycin (TOR) pathway, and leads to proliferation inhibition. To gain insight into how LKB1 mediates its effects during development, we generated zebrafish mutants in the single LKB1 ortholog. We show that in zebrafish lkb1 is dispensable for embryonic survival but becomes essential under conditions of energetic stress. After yolk absorption, lkb1 mutants rapidly exhaust their energy resources and die prematurely from starvation. Notably, intestinal epithelial cells were polarized properly in the lkb1 mutants. We show that attenuation of metabolic rate in lkb1 mutants, either by application of the TOR inhibitor rapamycin or by crossing with von Hippel-Lindau (vhl) mutant fish (in which constitutive hypoxia signaling results in reduced metabolic rate), suppresses key aspects of the lkb1 phenotype. Thus, we demonstrate a critical role for LKB1 in regulating energy homeostasis at the whole-organism level in a vertebrate. Zebrafish models of Lkb1 inactivation could provide a platform for chemical genetic screens to identify compounds that target accelerated metabolism, a key feature of tumor cells.
Assuntos
Metabolismo Energético , Proteínas Serina-Treonina Quinases/metabolismo , Estresse Fisiológico , Peixe-Zebra/metabolismo , Animais , Metabolismo Basal , Polaridade Celular , Embrião não Mamífero/enzimologia , Embrião não Mamífero/patologia , Privação de Alimentos , Fator de Crescimento Insulin-Like I/metabolismo , Intestinos/patologia , Larva/citologia , Larva/metabolismo , Mutação/genética , Fenótipo , Fosfatidilinositol 3-Quinases/metabolismo , Transdução de Sinais , Análise de Sobrevida , Serina-Treonina Quinases TOR/metabolismo , Peixe-Zebra/embriologia , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismoRESUMO
The CDKN2b-CDKN2a locus on chromosome 9p21 in human (chromosome 4 in mouse) is frequently lost in cancer. The locus encodes three cell cycle inhibitory proteins: p15INK4b encoded by CDKN2b, p16INK4a encoded by CDKN2a and p14ARF (p19Arf in mice) encoded by an alternative reading frame of CDKN2a (ref. 1). Whereas the tumour suppressor functions for p16INK4a and p14ARF have been firmly established, the role of p15INK4b remains ambiguous. However, many 9p21 deletions also remove CDKN2b, so we hypothesized a synergistic effect of the combined deficiency for p15INK4b, p14ARF and p16INK4a. Here we report that mice deficient for all three open reading frames (Cdkn2ab-/-) are more tumour-prone and develop a wider spectrum of tumours than Cdkn2a mutant mice, with a preponderance of skin tumours and soft tissue sarcomas (for example, mesothelioma) frequently composed of mixed cell types and often showing biphasic differentiation. Cdkn2ab-/- mouse embryonic fibroblasts (MEFs) are substantially more sensitive to oncogenic transformation than Cdkn2a mutant MEFs. Under conditions of stress, p15Ink4b protein levels are significantly elevated in MEFs deficient for p16Ink4a. Our data indicate that p15Ink4b can fulfil a critical backup function for p16Ink4a and provide an explanation for the frequent loss of the complete CDKN2b-CDKN2a locus in human tumours.
Assuntos
Inibidor de Quinase Dependente de Ciclina p15/metabolismo , Inibidor p16 de Quinase Dependente de Ciclina/deficiência , Animais , Ciclo Celular , Diferenciação Celular , Linhagem Celular Transformada , Proliferação de Células , Transformação Celular Neoplásica , Células Cultivadas , Inibidor de Quinase Dependente de Ciclina p15/deficiência , Inibidor de Quinase Dependente de Ciclina p15/genética , Inibidor p16 de Quinase Dependente de Ciclina/genética , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Embrião de Mamíferos/citologia , Fibroblastos , Deleção de Genes , Genes Supressores de Tumor , Humanos , Camundongos , Oncogenes/genética , Fases de Leitura Aberta/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Sarcoma/genética , Sarcoma/metabolismo , Sarcoma/patologia , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologiaRESUMO
Small cell lung cancer (SCLC) is a highly aggressive human tumor with a more than 95% mortality rate. Its ontogeny and molecular pathogenesis remains poorly understood. We established a mouse model for neuroendocrine (NE) lung tumors by conditional inactivation of Rb1 and Trp53 in mouse lung epithelial cells. Mice carrying conditional alleles for both Rb1 and Trp53 developed with high incidence aggressive lung tumors with striking morphologic and immunophenotypic similarities to SCLC. Most of these tumors, which we designate MSCLC (murine small cell lung carcinoma), diffusely spread through the lung and gave rise to extrapulmonary metastases. In our model, inactivation of both Rb1 and p53 was a prerequisite for the pathogenesis of SCLC.
Assuntos
Carcinoma de Células Pequenas/genética , Regulação Neoplásica da Expressão Gênica/fisiologia , Genes p53/genética , Neoplasias Pulmonares/genética , Proteína do Retinoblastoma/genética , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Carcinoma de Células Pequenas/etiologia , Proteínas de Ligação a DNA/genética , Genes p53/fisiologia , Neoplasias Pulmonares/etiologia , Camundongos , Camundongos Transgênicos , Fatores de Transcrição/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
Whereas target-specific drugs are available for treating ERBB2-overexpressing and hormone receptor-positive breast cancers, no tailored therapy exists for hormone receptor- and ERBB2-negative ("triple-negative") mammary carcinomas. Triple-negative tumors account for 15% of all breast cancers and frequently harbor defects in DNA double-strand break repair through homologous recombination (HR), such as BRCA1 dysfunction. The DNA-repair defects characteristic of BRCA1-deficient cells confer sensitivity to poly(ADP-ribose) polymerase 1 (PARP1) inhibition, which could be relevant to treatment of triple-negative tumors. To evaluate PARP1 inhibition in a realistic in vivo setting, we tested the PARP inhibitor AZD2281 in a genetically engineered mouse model (GEMM) for BRCA1-associated breast cancer. Treatment of tumor-bearing mice with AZD2281 inhibited tumor growth without signs of toxicity, resulting in strongly increased survival. Long-term treatment with AZD2281 in this model did result in the development of drug resistance, caused by up-regulation of Abcb1a/b genes encoding P-glycoprotein efflux pumps. This resistance to AZD2281 could be reversed by coadministration of the P-glycoprotein inhibitor tariquidar. Combination of AZD2281 with cisplatin or carboplatin increased the recurrence-free and overall survival, suggesting that AZD2281 potentiates the effect of these DNA-damaging agents. Our results demonstrate in vivo efficacy of AZD2281 against BRCA1-deficient breast cancer and illustrate how GEMMs of cancer can be used for preclinical evaluation of novel therapeutics and for testing ways to overcome or circumvent therapy resistance.
Assuntos
Antineoplásicos/uso terapêutico , Proteína BRCA1/genética , Neoplasias Mamárias Animais/tratamento farmacológico , Ftalazinas/uso terapêutico , Piperazinas/uso terapêutico , Compostos de Platina/uso terapêutico , Inibidores de Poli(ADP-Ribose) Polimerases , Animais , Inibidores da Aromatase/uso terapêutico , Cisplatino/uso terapêutico , Dano ao DNA , Reparo do DNA/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Neoplasias Mamárias Animais/genética , Neoplasias Mamárias Animais/patologia , Camundongos , Camundongos Transgênicos , Transplante de Neoplasias , Poli(ADP-Ribose) Polimerases/genéticaRESUMO
Metastasis is a major factor in the malignancy of cancers, and is often responsible for the failure of cancer treatment. Anoikis (apoptosis resulting from loss of cell-matrix interactions) has been suggested to act as a physiological barrier to metastasis; resistance to anoikis may allow survival of cancer cells during systemic circulation, thereby facilitating secondary tumour formation in distant organs. In an attempt to identify metastasis-associated oncogenes, we designed an unbiased, genome-wide functional screen solely on the basis of anoikis suppression. Here, we report the identification of TrkB, a neurotrophic tyrosine kinase receptor, as a potent and specific suppressor of caspase-associated anoikis of non-malignant epithelial cells. By activating the phosphatidylinositol-3-OH kinase/protein kinase B pathway, TrkB induced the formation of large cellular aggregates that survive and proliferate in suspension. In mice, these cells formed rapidly growing tumours that infiltrated lymphatics and blood vessels to colonize distant organs. Consistent with the ability of TrkB to suppress anoikis, metastases--whether small vessel infiltrates or large tumour nodules--contained very few apoptotic cells. These observations demonstrate the potent oncogenic effects of TrkB and uncover a specific pro-survival function that may contribute to its metastatic capacity, providing a possible explanation for the aggressive nature of human tumours that overexpress TrkB.
Assuntos
Anoikis , Metástase Neoplásica , Oncogenes/fisiologia , Receptor trkB/metabolismo , Animais , Fator Neurotrófico Derivado do Encéfalo/genética , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Caspases/metabolismo , Adesão Celular , Linhagem Celular , Movimento Celular , Sobrevivência Celular , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Transplante de Células , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Células Epiteliais/transplante , Biblioteca Gênica , Mucosa Intestinal/metabolismo , Intestinos/citologia , Intestinos/patologia , Camundongos , Camundongos Nus , Metástase Neoplásica/patologia , Neoplasias/metabolismo , Neoplasias/patologia , Oncogenes/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-akt , Ratos , Receptor trkB/genética , Taxa de Sobrevida , Transdução GenéticaRESUMO
We have generated mouse models of malignant mesothelioma (MM) based upon disruption of the Bap1, Nf2, and Cdkn2ab tumor suppressor loci in various combinations as also frequently observed in human MM. Inactivation of all three loci in the mesothelial lining of the thoracic cavity leads to a highly aggressive MM that recapitulates the histological features and gene expression profile observed in human patients. The tumors also show a similar inflammatory phenotype. Bap1 deletion alone does not cause MM but dramatically accelerates MM development when combined with Nf2 and Cdkn2ab (hereafter BNC) disruption. The accelerated tumor development is accompanied by increased Polycomb repression and EZH2-mediated redistribution of H3K27me3 toward promoter sites with concomitant activation of PI3K and MAPK pathways. Treatment of BNC tumor-bearing mice with cisplatin and pemetrexed, the current frontline treatment, prolongs survival. This makes the autochthonous mouse model described here very well suited to explore the pathogenesis of MM and validate new treatment regimens for MM, including immunotherapy.
Assuntos
Inibidor de Quinase Dependente de Ciclina p15/metabolismo , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Deleção de Genes , Mesotelioma Maligno/metabolismo , Neurofibromina 2/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Ubiquitina Tiolesterase/metabolismo , Animais , Modelos Animais de Doenças , Progressão da Doença , Humanos , Imunofenotipagem , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Mesotelioma Maligno/genética , Mesotelioma Maligno/patologia , Camundongos , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Transcrição Gênica/efeitos dos fármacos , Microambiente Tumoral/efeitos dos fármacosRESUMO
Increasing evidence from epidemiological and pathological studies suggests a role of the immune system in the initiation and progression of multiple cancers, including prostate cancer. Reports on the contribution of the adaptive immune system are contradictive, since both suppression and acceleration of disease development have been reported. This study addresses the functional role of lymphocytes in prostate cancer development using a genetically engineered mouse model (GEMM) of human c-Myc driven prostate cancer (Hi-Myc mice) combined with B and T cell deficiency (RAG1-/- mice). From a pre-cancerous stage on, Hi-Myc mice showed higher accumulation of immune cells in their prostates then wild-type mice, of which macrophages were the most abundant. The onset of invasive adenocarcinoma was delayed in Hi-MycRAG1-/- compared to Hi-Myc mice and associated with decreased infiltration of leukocytes into the prostate. In addition, lower levels of the cytokines CXCL2, CCL5 and TGF-ß1 were detected in Hi-MycRAG1-/- compared to Hi-Myc mouse prostates. These results from a GEMM of prostate cancer provide new insights into the promoting role of the adaptive immune system in prostate cancer development. Our findings indicate that the endogenous adaptive immune system does not protect against de novo prostate carcinogenesis in Hi-Myc transgenic mice, but rather accelerates the formation of invasive adenocarcinomas. This may have implications for the development of novel treatment strategies.
RESUMO
Small cell lung cancer (SCLC) is an aggressive neuroendocrine tumor, and no effective treatment is available to date. Mouse models of SCLC based on the inactivation of Rb1 and Trp53 show frequent amplifications of the Nfib and Mycl genes. Here, we report that, although overexpression of either transcription factor accelerates tumor growth, NFIB specifically promotes metastatic spread. High NFIB levels are associated with expansive growth of a poorly differentiated and almost exclusively E-cadherin (CDH1)-negative invasive tumor cell population. Consistent with the mouse data, we find that NFIB is overexpressed in almost all tested human metastatic high-grade neuroendocrine lung tumors, warranting further assessment of NFIB as a tumor progression marker in a clinical setting.
Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Fatores de Transcrição NFI/metabolismo , Carcinoma de Pequenas Células do Pulmão/metabolismo , Carcinoma de Pequenas Células do Pulmão/patologia , Animais , Caderinas/metabolismo , Proliferação de Células/fisiologia , Modelos Animais de Doenças , Progressão da Doença , Regulação Neoplásica da Expressão Gênica/fisiologia , Humanos , Camundongos , Metástase Neoplásica/patologia , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteína do Retinoblastoma/metabolismo , Proteína Supressora de Tumor p53/metabolismoRESUMO
Bmi1 is a member of the polycomb repressive complex 1 and plays different roles during embryonic development, depending on the developmental context. Bmi1 over expression is observed in many types of cancer, including tumors of astroglial and neural origin. Although genetic depletion of Bmi1 has been described to result in tumor inhibitory effects partly through INK4A/Arf mediated senescence and apoptosis and also through INK4A/Arf independent effects, it has not been proven that Bmi1 can be causally involved in the formation of these tumors. To see whether this is the case, we developed two conditional Bmi1 transgenic models that were crossed with GFAP-Cre mice to activate transgenic expression in neural and glial lineages. We show here that these mice generate intermediate and anterior lobe pituitary tumors that are positive for ACTH and beta-endorphin. Combined transgenic expression of Bmi1 together with conditional loss of Rb resulted in pituitary tumors but was insufficient to induce medulloblastoma therefore indicating that the oncogenic function of Bmi1 depends on regulation of p16(INK4A)/Rb rather than on regulation of p19(ARF)/p53. Human pituitary adenomas show Bmi1 overexpression in over 50% of the cases, which indicates that Bmi1 could be causally involved in formation of these tumors similarly as in our mouse model.
Assuntos
Proteína Glial Fibrilar Ácida/metabolismo , Integrases/metabolismo , Proteínas Nucleares/genética , Neoplasias Hipofisárias/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Repressoras/genética , Transgenes/genética , Animais , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Expressão Gênica , Humanos , Meduloblastoma/genética , Meduloblastoma/patologia , Camundongos , Camundongos Transgênicos , Neoplasias Hipofisárias/patologia , Complexo Repressor Polycomb 1 , Proteína do Retinoblastoma/metabolismo , Proteína Supressora de Tumor p53/metabolismo , beta-Endorfina/metabolismoRESUMO
Prostate cancer (PCa) is a major lethal malignancy in men, but the molecular events and their interplay underlying prostate carcinogenesis remain poorly understood. Epigenetic events and the upregulation of polycomb group silencing proteins including Bmi1 have been described to occur during PCa progression. Here, we found that conditional overexpression of Bmi1 in mice induced prostatic intraepithelial neoplasia, and elicited invasive adenocarcinoma when combined with PTEN haploinsufficiency. In addition, Bmi1 and the PI3K/Akt pathway were coactivated in a substantial fraction of human high-grade tumors. We found that Akt mediated Bmi1 phosphorylation, enhancing its oncogenic potential in an Ink4a/Arf-independent manner. This process also modulated the DNA damage response and affected genomic stability. Together, our findings demonstrate the etiological role of Bmi1 in PCa, unravel an oncogenic collaboration between Bmi1 and the PI3K/Akt pathway, and provide mechanistic insights into the modulation of Bmi1 function by phosphorylation during prostate carcinogenesis.
Assuntos
Adenocarcinoma/metabolismo , Reparo do DNA , Proteínas Nucleares/metabolismo , Neoplasia Prostática Intraepitelial/metabolismo , Neoplasias da Próstata/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Repressoras/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Adenocarcinoma/enzimologia , Adenocarcinoma/patologia , Animais , Linhagem Celular Tumoral , Transformação Celular Neoplásica , Quebras de DNA de Cadeia Dupla , Ativação Enzimática , Instabilidade Genômica , Haploinsuficiência , Histonas/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Camundongos Transgênicos , Gradação de Tumores , Transplante de Neoplasias , Proteínas Nucleares/genética , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo , Fosforilação , Complexo Repressor Polycomb 1 , Próstata/metabolismo , Próstata/patologia , Neoplasia Prostática Intraepitelial/enzimologia , Neoplasia Prostática Intraepitelial/patologia , Neoplasias da Próstata/enzimologia , Neoplasias da Próstata/patologia , Processamento de Proteína Pós-Traducional , Proteínas Proto-Oncogênicas/genética , Proteínas Repressoras/genética , Transdução de Sinais , UbiquitinaçãoRESUMO
PURPOSE: To develop a transgenic mouse model of glioma that can be conveniently used for testing therapy intervention strategies. High-grade glioma is a devastating and uniformly fatal disease for which better therapy is urgently needed. Typical for high-grade glioma is that glioma cells infiltrate extensively into surrounding pivotal brain structures, thereby rendering current treatments largely ineffective. Evaluation of novel therapies requires the availability of appropriate glioma mouse models. EXPERIMENTAL DESIGN: High-grade gliomas were induced by stereotactic intracranial injection of lentiviral GFAP-Cre or CMV-Cre vectors into compound LoxP-conditional mice, resulting in K-Ras(v12) expression and loss of p16(Ink4a)/p19(Arf) with or without concomitant loss of p53 or Pten. RESULTS: Tumors reproduced many of the features that are characteristic for human high-grade gliomas, including invasiveness and blood-brain barrier functionality. Especially, CMV-Cre injection into p53;Ink4a/Arf;K-Ras(v12) mice resulted in high-grade glioma with a short tumor latency (2-3 weeks) and full penetrance. Early detection and follow-up was accomplished by noninvasive bioluminescence imaging, and the practical utility for therapy intervention was shown in a study with temozolomide. CONCLUSION: We have developed a realistic high-grade glioma model that can be used with almost the same convenience as traditional xenograft models, thus allowing its implementation at the forefront of preclinical evaluation of new treatments.
Assuntos
Neoplasias Encefálicas/genética , Neoplasias Encefálicas/terapia , Modelos Animais de Doenças , Glioma/genética , Glioma/terapia , Fatores de Ribosilação do ADP/genética , Animais , Neoplasias Encefálicas/patologia , Genes p16 , Genes p53 , Vetores Genéticos , Glioma/patologia , Lentivirus/genética , Camundongos , Camundongos Transgênicos , PTEN Fosfo-Hidrolase/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas p21(ras) , Transfecção , Proteínas ras/genéticaRESUMO
Malignant mesothelioma is a devastating disease that has been associated with loss of Neurofibromatosis type 2 (NF2) and genetic lesions affecting RB and P53 pathways. We introduced similar lesions in the mesothelial lining of the thoracic cavity of mice. Mesothelioma developed at high incidence in Nf2;Ink4a/Arf and Nf2;p53 conditional knockout mice with median survival times of approximately 30 and 20 weeks, respectively. Murine mesothelioma closely mimicked human malignant mesothelioma. Conditional Nf2;Ink4a/Arf mice showed increased pleural invasion compared to conditional Nf2;p53 mice. Interestingly, upon Ink4a loss in the latter mice median survival was significantly reduced and all tumors were highly invasive, suggesting that Ink4a loss substantially contributes to the poor clinical outcome of malignant mesothelioma.
Assuntos
Transformação Celular Neoplásica/patologia , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Células Epiteliais/metabolismo , Mesotelioma/patologia , Neurofibromatose 2/metabolismo , Cavidade Torácica/metabolismo , Neoplasias Torácicas/patologia , Proteína Supressora de Tumor p53/metabolismo , Adenoviridae/genética , Animais , Linhagem Celular Tumoral , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Inibidor p16 de Quinase Dependente de Ciclina/genética , Células Epiteliais/patologia , Células Epitelioides/metabolismo , Células Epitelioides/patologia , Vetores Genéticos , Genótipo , Imuno-Histoquímica , Integrases/genética , Integrases/metabolismo , Perda de Heterozigosidade , Medições Luminescentes , Mesotelioma/genética , Mesotelioma/metabolismo , Camundongos , Camundongos Knockout , Tumor Misto Maligno/metabolismo , Tumor Misto Maligno/patologia , Invasividade Neoplásica , Neoplasias Experimentais/genética , Neoplasias Experimentais/metabolismo , Neoplasias Experimentais/patologia , Neurofibromatose 2/genética , Fenótipo , Recombinação Genética , Sarcoma/metabolismo , Sarcoma/patologia , Cavidade Torácica/patologia , Neoplasias Torácicas/genética , Neoplasias Torácicas/metabolismo , Fatores de Tempo , Proteína Supressora de Tumor p53/genéticaRESUMO
Women carrying germ-line mutations in BRCA1 are strongly predisposed to developing breast cancers with characteristic features also observed in sporadic basal-like breast cancers. They appear as high-grade tumors with high proliferation rates and pushing borders. On the molecular level, they are negative for hormone receptors and ERBB2, display frequent TP53 mutations, and express basal epithelial markers. To study the role of BRCA1 and P53 loss of function in breast cancer development, we generated conditional mouse models with tissue-specific mutation of Brca1 and/or p53 in basal epithelial cells. Somatic loss of both BRCA1 and p53 resulted in the rapid and efficient formation of highly proliferative, poorly differentiated, estrogen receptor-negative mammary carcinomas with pushing borders and increased expression of basal epithelial markers, reminiscent of human basal-like breast cancer. BRCA1- and p53-deficient mouse mammary tumors exhibit dramatic genomic instability, and their molecular signatures resemble those of human BRCA1-mutated breast cancers. Thus, these tumors display important hallmarks of hereditary breast cancers in BRCA1-mutation carriers.