RESUMEN
Interference with microtubule dynamics in mitosis activates the spindle assembly checkpoint (SAC) to prevent chromosome segregation errors. The SAC induces mitotic arrest by inhibiting the anaphase-promoting complex (APC) via the mitotic checkpoint complex (MCC). The MCC component MAD2 neutralizes the critical APC cofactor, CDC20, preventing exit from mitosis. Extended mitotic arrest can promote mitochondrial apoptosis and caspase activation. However, the impact of mitotic cell death on tissue homeostasis in vivo is ill-defined. By conditional MAD2 overexpression, we observe that chronic SAC activation triggers bone marrow aplasia and intestinal atrophy in mice. While myelosuppression can be compensated for, gastrointestinal atrophy is detrimental. Remarkably, deletion of pro-apoptotic Bim/Bcl2l11 prevents gastrointestinal syndrome, while neither loss of Noxa/Pmaip or co-deletion of Bid and Puma/Bbc3 has such a protective effect, identifying BIM as rate-limiting apoptosis effector in mitotic cell death of the gastrointestinal epithelium. In contrast, only overexpression of anti-apoptotic BCL2, but none of the BH3-only protein deficiencies mentioned above, can mitigate myelosuppression. Our findings highlight tissue and cell-type-specific survival dependencies in response to SAC perturbation in vivo.
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Proteínas Reguladoras de la Apoptosis , Apoptosis , Proteína 11 Similar a Bcl2 , Puntos de Control de la Fase M del Ciclo Celular , Proteínas Mad2 , Proteínas Proto-Oncogénicas c-bcl-2 , Animales , Proteína 11 Similar a Bcl2/metabolismo , Proteína 11 Similar a Bcl2/genética , Ratones , Proteínas Mad2/metabolismo , Proteínas Mad2/genética , Proteínas Reguladoras de la Apoptosis/metabolismo , Proteínas Reguladoras de la Apoptosis/genética , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/genética , Atrofia , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas/genética , Mitosis , Proteína Proapoptótica que Interacciona Mediante Dominios BH3/metabolismo , Proteína Proapoptótica que Interacciona Mediante Dominios BH3/genética , Proteínas Cdc20/metabolismo , Proteínas Cdc20/genética , Médula Ósea/patología , Médula Ósea/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Proteínas Supresoras de TumorRESUMEN
Precision oncology has revolutionized the treatment of ALK-positive lung cancer with targeted therapies. However, an unmet clinical need still to address is the treatment of refractory tumors that contain drug-induced resistant mutations in the driver oncogene or exhibit resistance through the activation of diverse mechanisms. In this study, we established mouse tumor-derived cell models representing the two most prevalent EML4-ALK variants in human lung adenocarcinomas and characterized their proteomic profiles to gain insights into the underlying resistance mechanisms. We showed that Eml4-Alk variant 3 confers a worse response to ALK inhibitors, suggesting its role in promoting resistance to targeted therapy. In addition, proteomic analysis of brigatinib-treated cells revealed the upregulation of SRC kinase, a protein frequently activated in cancer. Co-targeting of ALK and SRC showed remarkable inhibitory effects in both ALK-driven murine and ALK-patient-derived lung tumor cells. This combination induced cell death through a multifaceted mechanism characterized by profound perturbation of the (phospho)proteomic landscape and a synergistic suppressive effect on the mTOR pathway. Our study demonstrates that the simultaneous inhibition of ALK and SRC can potentially overcome resistance mechanisms and enhance clinical outcomes in ALK-positive lung cancer patients. ONE SENTENCE SUMMARY: Co-targeting ALK and SRC enhances ALK inhibitor response in lung cancer by affecting the proteomic profile, offering hope for overcoming resistance and improving clinical outcomes.
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Quinasa de Linfoma Anaplásico , Resistencia a Antineoplásicos , Neoplasias Pulmonares , Compuestos Organofosforados , Inhibidores de Proteínas Quinasas , Proteoma , Familia-src Quinasas , Animales , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Humanos , Quinasa de Linfoma Anaplásico/antagonistas & inhibidores , Quinasa de Linfoma Anaplásico/genética , Quinasa de Linfoma Anaplásico/metabolismo , Familia-src Quinasas/antagonistas & inhibidores , Familia-src Quinasas/metabolismo , Ratones , Proteoma/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Resistencia a Antineoplásicos/efectos de los fármacos , Línea Celular Tumoral , Pirimidinas/farmacología , Proteómica/métodos , Proteínas de Fusión Oncogénica/genética , Proteínas de Fusión Oncogénica/metabolismo , Proteínas de Fusión Oncogénica/antagonistas & inhibidores , Adenocarcinoma del Pulmón/tratamiento farmacológico , Adenocarcinoma del Pulmón/patología , Adenocarcinoma del Pulmón/genética , Adenocarcinoma del Pulmón/metabolismo , Transducción de Señal/efectos de los fármacosRESUMEN
Human airway epithelium (HAE) represents the primary site of viral infection for SARS-CoV-2. Comprising different cell populations, a lot of research has been aimed at deciphering the major cell types and infection dynamics that determine disease progression and severity. However, the cell type-specific replication kinetics, as well as the contribution of cellular composition of the respiratory epithelium to infection and pathology are still not fully understood. Although experimental advances, including Air-liquid interface (ALI) cultures of reconstituted pseudostratified HAE, as well as lung organoid systems, allow the observation of infection dynamics under physiological conditions in unprecedented level of detail, disentangling and quantifying the contribution of individual processes and cells to these dynamics remains challenging. Here, we present how a combination of experimental data and mathematical modelling can be used to infer and address the influence of cell type specific infectivity and tissue composition on SARS-CoV-2 infection dynamics. Using a stepwise approach that integrates various experimental data on HAE culture systems with regard to tissue differentiation and infection dynamics, we develop an individual cell-based model that enables investigation of infection and regeneration dynamics within pseudostratified HAE. In addition, we present a novel method to quantify tissue integrity based on image data related to the standard measures of transepithelial electrical resistance measurements. Our analysis provides a first aim of quantitatively assessing cell type specific infection kinetics and shows how tissue composition and changes in regeneration capacity, as e.g. in smokers, can influence disease progression and pathology. Furthermore, we identified key measurements that still need to be assessed in order to improve inference of cell type specific infection kinetics and disease progression. Our approach provides a method that, in combination with additional experimental data, can be used to disentangle the complex dynamics of viral infection and immunity within human airway epithelial culture systems.
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COVID-19 , Humanos , COVID-19/metabolismo , Células Epiteliales/metabolismo , SARS-CoV-2 , Células Cultivadas , Epitelio , Mucosa Respiratoria/metabolismo , Mucosa Respiratoria/patologíaRESUMEN
Respiratory viruses cause mild to severe diseases in humans every year, constituting a major public health problem. Characterizing the pathogenesis in physiologically relevant models is crucial for developing efficient vaccines and therapeutics. Here, we show that lung organoids derived from human primary or lung tumor tissue maintain the cellular composition and characteristics of the original tissue. Moreover, we show that these organoids sustain viral replication with particular infection foci formation, and they activate the expression of interferon-associated and proinflammatory genes responsible for mediating a robust innate immune response. All together, we show that three-dimensional (3D) lung organoids constitute a relevant platform to model diseases and enable the development of drug screenings. IMPORTANCE Three-dimensional (3D) human lung organoids reflect the native cell composition of the lung as well as its physiological properties. Human 3D lung organoids offer ideal conditions, such as timely availability in large quantities and high physiological relevance for reassessment and prediction of disease outbreaks of respiratory pathogens and pathogens that use the lung as a primary entry portal. Human lung organoids can be used in basic research and diagnostic settings as early warning cell culture systems and also serve as a relevant platform for modeling infectious diseases and drug development. They can be used to characterize pathogens and analyze the influence of infection on, for example, immunological parameters, such as the expression of interferon-associated and proinflammatory genes in the context of cancer. In our study, we found that cancer-derived lung organoids were more sensitive to influenza A virus infection than those derived from healthy tissue and demonstrated a decreased innate immune response.
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Pulmón , Técnicas de Cultivo de Órganos , Organoides , Enfermedades Transmisibles/diagnóstico , Enfermedades Transmisibles/inmunología , Humanos , Inmunidad Innata , Interferones , Pulmón/patología , Técnicas de Cultivo de Órganos/métodos , Organoides/inmunología , Organoides/virologíaRESUMEN
BACKGROUND: Survival after curative resection of early-stage lung adenocarcinoma (LUAD) varies and prognostic biomarkers are urgently needed. METHODS: Large-format tissue samples from a prospective cohort of 200 patients with resected LUAD were immunophenotyped for cancer hallmarks TP53, NF1, CD45, PD-1, PCNA, TUNEL and FVIII, and were followed for a median of 2.34 (95% CI 1.71-3.49)â years. RESULTS: Unsupervised hierarchical clustering revealed two patient subgroups with similar clinicopathological features and genotype, but with markedly different survival: "proliferative" patients (60%) with elevated TP53, NF1, CD45 and PCNA expression had 50% 5-year overall survival, while "apoptotic" patients (40%) with high TUNEL had 70% 5-year survival (hazard ratio 2.23, 95% CI 1.33-3.80; p=0.0069). Cox regression and machine learning algorithms including random forests built clinically useful models: a score to predict overall survival and a formula and nomogram to predict tumour phenotype. The distinct LUAD phenotypes were validated in The Cancer Genome Atlas and KMplotter data, and showed prognostic power supplementary to International Association for the Study of Lung Cancer tumour-node-metastasis stage and World Health Organization histologic classification. CONCLUSIONS: Two molecular subtypes of LUAD exist and their identification provides important prognostic information.
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Adenocarcinoma del Pulmón , Neoplasias Pulmonares , Adenocarcinoma del Pulmón/genética , Adenocarcinoma del Pulmón/patología , Humanos , Neoplasias Pulmonares/patología , Fenotipo , Pronóstico , Antígeno Nuclear de Célula en Proliferación/genética , Estudios ProspectivosRESUMEN
MOTIVATION: Whole-genome bisulfite sequencing (WGBS) measures DNA methylation at base pair resolution resulting in large bedGraph like coverage files. Current options for processing such files are hindered by discrepancies in file format specification, speed, and memory requirements. RESULTS: We developed methrix, an R package, which provides a toolset for systematic analysis of large datasets. Core functionality of the package includes a comprehensive bedGraph or similar tab-separated text file reader-which summarizes methylation calls based on annotated reference indices, infers and collapses strands and handles uncovered reference CpG sites while facilitating a flexible input file format specification. Additional optimized functions for quality control filtering, subsetting and visualization allow user-friendly and effective processing of WGBS results. Easy integration with tools for differentially methylated region (DMR) calling and annotation further eases the analysis of genome-wide methylation data. Overall, methrix enriches established WGBS workflows by bringing together computational efficiency and versatile functionality. AVAILABILITY AND IMPLEMENTATION: Methrix is implemented as an R package, made available under MIT license at https://github.com/CompEpigen/methrix and can be installed from the Bioconductor repository. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.
RESUMEN
Patterns of gene expression in tumors can arise as a consequence of or result in genomic instability, characterized by the accumulation of somatic copy number alterations (SCNAs) and point mutations (PMs). Expression signatures have been widely used as markers for genomic instability, and both SCNAs and PMs could be thought to associate with distinct signatures given their different formation mechanisms. Here we test this notion by systematically investigating SCNA, PM, and transcriptome data from 2660 cancer patients representing 11 tumor types. Notably, our data indicate that similar expression signatures can be derived from correlating gene expression with either SCNA or PM load. Gene sets related to cell growth and proliferation generally associated positively, and immunoregulatory gene sets negatively, with variant burden. In-depth analyses revealed several genes whose de-regulation correlates with SCNA but not with PM burden, yielding downstream effectors of TP53 and MYC signaling unique to high-SCNA tumors. We compared our findings to expression changes observed in two different cancer mouse models with persistent mitotic chromosomal instability, observing a decrease in proliferative expression signatures. Our results suggest that overexpression of cell-cycle-related genes are a characteristic of proliferation, and likely tumor evolution, rather than ongoing genomic instability.
Asunto(s)
Aneuploidia , Proliferación Celular , Regulación Neoplásica de la Expresión Génica , Neoplasias/genética , Transcriptoma , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Variaciones en el Número de Copia de ADN , Inestabilidad Genómica , Humanos , Acumulación de Mutaciones , Mutación PuntualRESUMEN
Inhibition of an initiating oncogene often leads to extensive tumour cell death, a phenomenon known as oncogene addiction. This has led to the search for compounds that specifically target and inhibit oncogenes as anticancer agents. However, there has been no systematic exploration of whether chromosomal instability generated as a result of deregulation of the mitotic checkpoint pathway, a frequent characteristic of solid tumours, has any effect on oncogene addiction. Here we show that induction of chromosome instability by overexpression of the mitotic checkpoint gene Mad2 in mice does not affect the regression of Kras-driven lung tumours when Kras is inhibited. However, tumours that experience transient Mad2 overexpression and consequent chromosome instability recur at markedly elevated rates. The recurrent tumours are highly aneuploid and have varied activation of pro-proliferative pathways. Thus, early chromosomal instability may be responsible for tumour relapse after seemingly effective anticancer treatments.
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Proteínas de Ciclo Celular/metabolismo , Inestabilidad Cromosómica , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Recurrencia Local de Neoplasia/metabolismo , Oncogenes/fisiología , Proteínas Proto-Oncogénicas p21(ras)/deficiencia , Aneuploidia , Animales , Proteínas de Ciclo Celular/genética , Inestabilidad Cromosómica/genética , Neoplasias Pulmonares/genética , Proteínas Mad2 , Ratones , Ratones Transgénicos , Recurrencia Local de Neoplasia/patología , Oncogenes/genética , Proteínas Proto-Oncogénicas p21(ras)/antagonistas & inhibidores , Proteínas Proto-Oncogénicas p21(ras)/genética , Proteínas Proto-Oncogénicas p21(ras)/metabolismoRESUMEN
Mad2 is an essential component of the spindle checkpoint that blocks activation of Separase and dissolution of sister chromatids until microtubule attachment to kinetochores is complete. We show here that overexpression of Mad2 in transgenic mice leads to a wide variety of neoplasias, appearance of broken chromosomes, anaphase bridges, and whole-chromosome gains and losses, as well as acceleration of myc-induced lymphomagenesis. Moreover, continued overexpression of Mad2 is not required for tumor maintenance, unlike the majority of oncogenes studied to date. These results demonstrate that transient Mad2 overexpression and chromosome instability can be an important stimulus in the initiation and progression of different cancer subtypes.
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Aneuploidia , Proteínas de Ciclo Celular/metabolismo , Transformación Celular Neoplásica/genética , Neoplasias/genética , Animales , Inestabilidad Cromosómica , Expresión Génica , Humanos , Hibridación Fluorescente in Situ , Proteínas Mad2 , Imagen por Resonancia Magnética , Ratones , Ratones Transgénicos , Neoplasias/metabolismoRESUMEN
ALK-positive NSCLC patients demonstrate initial responses to ALK tyrosine kinase inhibitor (TKI) treatments, but eventually develop resistance, causing rapid tumor relapse and poor survival rates. Growing evidence suggests that the combination of drug and immune therapies greatly improves patient survival; however, due to the low immunogenicity of the tumors, ALK-positive patients do not respond to currently available immunotherapies. Tumor-associated macrophages (TAMs) play a crucial role in facilitating lung cancer growth by suppressing tumoricidal immune activation and absorbing chemotherapeutics. However, they can also be programmed toward a pro-inflammatory tumor suppressive phenotype, which represents a highly active area of therapy development. Iron loading of TAMs can achieve such reprogramming correlating with an improved prognosis in lung cancer patients. We previously showed that superparamagnetic iron oxide nanoparticles containing core-cross-linked polymer micelles (SPION-CCPMs) target macrophages and stimulate pro-inflammatory activation. Here, we show that SPION-CCPMs stimulate TAMs to secrete reactive nitrogen species and cytokines that exert tumoricidal activity. We further show that SPION-CCPMs reshape the immunosuppressive Eml4-Alk lung tumor microenvironment (TME) toward a cytotoxic profile hallmarked by the recruitment of CD8+ T cells, suggesting a multifactorial benefit of SPION-CCPM application. When intratracheally instilled into lung cancer-bearing mice, SPION-CCPMs delay tumor growth and, after first line therapy with a TKI, halt the regrowth of relapsing tumors. These findings identify SPIONs-CCPMs as an adjuvant therapy, which remodels the TME, resulting in a delay in the appearance of resistant tumors.
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Crizotinib , Neoplasias Pulmonares , Nanopartículas Magnéticas de Óxido de Hierro , Microambiente Tumoral , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/patología , Microambiente Tumoral/efectos de los fármacos , Animales , Nanopartículas Magnéticas de Óxido de Hierro/química , Humanos , Ratones , Crizotinib/farmacología , Crizotinib/química , Antineoplásicos/farmacología , Antineoplásicos/química , Inhibidores de Proteínas Quinasas/farmacología , Inhibidores de Proteínas Quinasas/química , Línea Celular Tumoral , Macrófagos Asociados a Tumores/efectos de los fármacos , Macrófagos Asociados a Tumores/metabolismo , Proliferación Celular/efectos de los fármacos , FemeninoRESUMEN
Human development relies on the correct replication, maintenance and segregation of our genetic blueprints. How these processes are monitored across embryonic lineages, and why genomic mosaicism varies during development remain unknown. Using pluripotent stem cells, we identify that several patterning signals-including WNT, BMP, and FGF-converge into the modulation of DNA replication stress and damage during S-phase, which in turn controls chromosome segregation fidelity in mitosis. We show that the WNT and BMP signals protect from excessive origin firing, DNA damage and chromosome missegregation derived from stalled forks in pluripotency. Cell signalling control of chromosome segregation declines during lineage specification into the three germ layers, but re-emerges in neural progenitors. In particular, we find that the neurogenic factor FGF2 induces DNA replication stress-mediated chromosome missegregation during the onset of neurogenesis, which could provide a rationale for the elevated chromosomal mosaicism of the developing brain. Our results highlight roles for morphogens and cellular identity in genome maintenance that contribute to somatic mosaicism during mammalian development.
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Segregación Cromosómica , Replicación del ADN , Neurogénesis , Neurogénesis/genética , Animales , Humanos , Ratones , Daño del ADN , Transducción de Señal , Células Madre Pluripotentes/metabolismo , Células Madre Pluripotentes/citología , Proteínas Morfogenéticas Óseas/metabolismo , Proteínas Morfogenéticas Óseas/genética , Factor 2 de Crecimiento de Fibroblastos/metabolismo , Mitosis , MosaicismoRESUMEN
Lung cancer, the leading cause of cancer mortality, exhibits diverse histological subtypes and genetic complexities. Numerous preclinical mouse models have been developed to study lung cancer, but data from these models are disparate, siloed, and difficult to compare in a centralized fashion. Here we established the Lung Cancer Mouse Model Database (LCMMDB), an extensive repository of 1,354 samples from 77 transcriptomic datasets covering 974 samples from genetically engineered mouse models (GEMMs), 368 samples from carcinogen-induced models, and 12 samples from a spontaneous model. Meticulous curation and collaboration with data depositors have produced a robust and comprehensive database, enhancing the fidelity of the genetic landscape it depicts. The LCMMDB aligns 859 tumors from GEMMs with human lung cancer mutations, enabling comparative analysis and revealing a pressing need to broaden the diversity of genetic aberrations modeled in GEMMs. Accompanying this resource, we developed a web application that offers researchers intuitive tools for in-depth gene expression analysis. With standardized reprocessing of gene expression data, the LCMMDB serves as a powerful platform for cross-study comparison and lays the groundwork for future research, aiming to bridge the gap between mouse models and human lung cancer for improved translational relevance.
RESUMEN
We targeted the locus encoding the cyclin-dependent kinase 2 (CDK2) by homologous recombination in mouse embryonic stem (ES) cells. Embryonic fibroblasts lacking CDK2 proliferate normally and become immortal after continuous passage in culture. Elimination of a conditional Cdk2 allele in immortal cells does not have a significant effect on proliferation. Cdk2-/- mice are viable and survive for up to two years, indicating that CDK2 is also dispensable for proliferation and survival of most cell types. But CDK2 is essential for completion of prophase I during meiotic cell division in male and female germ cells, an unforeseen role for this cell cycle kinase.
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Quinasas CDC2-CDC28 , Quinasas Ciclina-Dependientes/fisiología , Meiosis/fisiología , Mitosis/fisiología , Oocitos/enzimología , Proteínas Serina-Treonina Quinasas/fisiología , Testículo/enzimología , Animales , Células Cultivadas , Quinasa 2 Dependiente de la Ciclina , Femenino , Fibroblastos , Masculino , Ratones , Ratones Noqueados , Oocitos/citología , Ovario/embriología , Pase Seriado , Espermatogénesis , Testículo/citología , Testículo/embriologíaRESUMEN
Chromosome instability (CIN) contributes to resistance to therapies and tumor evolution. Although natural killer (NK) cells can eliminate cells with complex karyotypes, high-CIN human tumors have an immunosuppressive phenotype. To understand which CIN-associated molecular features alter immune recognition during tumor evolution, we overexpress Polo-like kinase 1 (Plk1) in a Her2+ breast cancer model. These high-CIN tumors activate a senescence-associated secretory phenotype (SASP), upregulate PD-L1 and CD206, and induce non-cell-autonomous nuclear factor κB (NF-κß) signaling, facilitating immune evasion. Single-cell RNA sequencing from pre-neoplastic mammary glands unveiled the presence of Arg1+ macrophages, NK cells with reduced effector functions, and increased resting regulatory T cell infiltration. We further show that high PLK1-expressing human breast tumors display gene expression patterns associated with SASP, NF-κß signaling, and immune suppression. These findings underscore the need to understand the immune landscape in CIN tumors to identify more effective therapies, potentially combining immune checkpoint or NF-κß inhibitors with current treatments.
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Neoplasias de la Mama , Inestabilidad Cromosómica , Tolerancia Inmunológica , Quinasa Tipo Polo 1 , Escape del Tumor , Neoplasias de la Mama/genética , Neoplasias de la Mama/inmunología , Humanos , Animales , Ratones , Quinasa Tipo Polo 1/genética , Quinasa Tipo Polo 1/metabolismo , Línea Celular Tumoral , Receptor ErbB-2/genética , FN-kappa B/metabolismo , Antígeno B7-H1/metabolismo , Receptor de Manosa/metabolismo , Células Asesinas Naturales/inmunología , Xenoinjertos , Células MCF-7 , FemeninoRESUMEN
Tumor progression and evolution are frequently associated with chromosomal instability (CIN). Tumor cells often express high levels of the mitotic checkpoint protein MAD2, leading to mitotic arrest and cell death. However, some tumor cells are capable of exiting mitosis and consequently increasing CIN. How cells escape the mitotic arrest induced by MAD2 and proliferate with CIN is not well understood. Here, we explored loss-of-function screens and drug sensitivity tests associated with MAD2 levels in aneuploid cells and identified that aneuploid cells with high MAD2 levels are more sensitive to FOXM1 depletion. Inhibition of FOXM1 promotes MAD2-mediated mitotic arrest and exacerbates CIN. Conversely, elevating FOXM1 expression in MAD2-overexpressing human cell lines reverts prolonged mitosis and rescues mitotic errors, cell death and proliferative disadvantages. Mechanistically, we found that FOXM1 facilitates mitotic exit by inhibiting the spindle assembly checkpoint (SAC) and the expression of Cyclin B. Notably, we observed that FOXM1 is upregulated upon aneuploid induction in cells with dysfunctional SAC and error-prone mitosis, and these cells are sensitive to FOXM1 knockdown, indicating a novel vulnerability of aneuploid cells.
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Proteínas de Ciclo Celular , Mitosis , Humanos , Proteínas de Ciclo Celular/metabolismo , Proteínas Mad2/genética , Proteínas Mad2/metabolismo , Mitosis/genética , Línea Celular Tumoral , Huso Acromático/metabolismo , Aneuploidia , Proteína Forkhead Box M1/genética , Proteína Forkhead Box M1/metabolismoRESUMEN
The antiviral DNA cytosine deaminase APOBEC3B has been implicated as a source of mutation in many different cancers. Despite over 10 years of work, a causal relationship has yet to be established between APOBEC3B and any stage of carcinogenesis. Here we report a murine model that expresses tumor-like levels of human APOBEC3B after Cre-mediated recombination. Animals appear to develop normally with full-body expression of APOBEC3B. However, adult males manifest infertility and older animals of both sexes show accelerated rates of tumorigenesis (mostly lymphomas or hepatocellular carcinomas). Interestingly, primary tumors also show overt heterogeneity, and a subset spreads to secondary sites. Both primary and metastatic tumors exhibit increased frequencies of C-to-T mutations in TC dinucleotide motifs consistent with the established biochemical activity of APOBEC3B. Elevated levels of structural variation and insertion-deletion mutations also accumulate in these tumors. Together, these studies provide the first cause-and-effect demonstration that human APOBEC3B is an oncoprotein capable of causing a wide range of genetic changes and driving tumor formation in vivo .
RESUMEN
The antiviral DNA cytosine deaminase APOBEC3B has been implicated as a source of mutation in many cancers. However, despite years of work, a causal relationship has yet to be established in vivo. Here, we report a murine model that expresses tumor-like levels of human APOBEC3B. Animals expressing full-body APOBEC3B appear to develop normally. However, adult males manifest infertility, and older animals of both sexes show accelerated rates of carcinogenesis, visual and molecular tumor heterogeneity, and metastasis. Both primary and metastatic tumors exhibit increased frequencies of C-to-T mutations in TC dinucleotide motifs consistent with the established biochemical activity of APOBEC3B. Enrichment for APOBEC3B-attributable single base substitution mutations also associates with elevated levels of insertion-deletion mutations and structural variations. APOBEC3B catalytic activity is required for all of these phenotypes. Together, these studies provide a cause-and-effect demonstration that human APOBEC3B is capable of driving both tumor initiation and evolution in vivo.
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Neoplasias , Adulto , Humanos , Animales , Ratones , Mutación , Neoplasias/genética , Transformación Celular Neoplásica , Citidina Desaminasa/genética , Antígenos de Histocompatibilidad Menor/genéticaRESUMEN
BACKGROUND: RNA editing has been described as promoting genetic heterogeneity, leading to the development of multiple disorders, including cancer. The cytosine deaminase APOBEC3B is implicated in tumor evolution through DNA mutation, but whether it also functions as an RNA editing enzyme has not been studied. RESULTS: Here, we engineer a novel doxycycline-inducible mouse model of human APOBEC3B-overexpression to understand the impact of this enzyme in tissue homeostasis and address a potential role in C-to-U RNA editing. Elevated and sustained levels of APOBEC3B lead to rapid alteration of cellular fitness, major organ dysfunction, and ultimately lethality in mice. Importantly, RNA-sequencing of mouse tissues expressing high levels of APOBEC3B identifies frequent UCC-to-UUC RNA editing events that are not evident in the corresponding genomic DNA. CONCLUSIONS: This work identifies, for the first time, a new deaminase-dependent function for APOBEC3B in RNA editing and presents a preclinical tool to help understand the emerging role of APOBEC3B as a driver of carcinogenesis.
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Neoplasias , Edición de ARN , Humanos , Animales , Ratones , Citidina Desaminasa/genética , Citidina Desaminasa/metabolismo , Mutación , Neoplasias/patología , Antígenos de Histocompatibilidad Menor/genética , Antígenos de Histocompatibilidad Menor/metabolismo , ADN/metabolismoRESUMEN
The high plasticity of lung epithelial cells, has for many years, confounded the correct identification of the cell-of-origin of lung adenocarcinoma (LUAD), one of the deadliest malignancies worldwide. Here, we employ lineage-tracing mouse models to investigate the cell of origin of Eml4-Alk LUAD, and show that Club and Alveolar type 2 (AT2) cells give rise to tumours. We focus on Club cell originated tumours and find that Club cells experience an epigenetic switch by which they lose their lineage fidelity and gain an AT2-like phenotype after oncogenic transformation. Single-cell transcriptomic analyses identified two trajectories of Club cell evolution which are similar to the ones used during lung regeneration, suggesting that lung epithelial cells leverage on their plasticity and intrinsic regeneration mechanisms to give rise to a tumour. Together, this study highlights the role of Club cells in LUAD initiation, identifies the mechanism of Club cell lineage infidelity, confirms the presence of these features in human tumours, and unveils key mechanisms conferring LUAD heterogeneity.
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Adenocarcinoma del Pulmón , Neoplasias Pulmonares , Adenocarcinoma del Pulmón/genética , Adenocarcinoma del Pulmón/patología , Animales , Diferenciación Celular/genética , Transformación Celular Neoplásica/patología , Células Epiteliales/patología , Humanos , Pulmón/patología , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , RatonesRESUMEN
Hec1 (Highly Expressed in Cancer 1) is one of four proteins of the outer kinetochore Ndc80 complex involved in the dynamic interface between centromeres and spindle microtubules. Its overexpression is seen in a variety of human tumors and correlates with tumor grade and prognosis. We show here that the overexpression of Hec1 in an inducible mouse model results in mitotic checkpoint hyperactivation. As previously observed with overexpression of the Mad2 gene, hyperactivation of the mitotic checkpoint leads to aneuploidy in vitro and is sufficient to generate tumors in vivo that harbor significant levels of aneuploidy. These results underscore the role of chromosomal instability as a result of mitotic checkpoint hyperactivation in the initiation of tumorigenesis.