RESUMEN
Intracellular organelle organization is conserved in eukaryotic cells and is primarily achieved through active transport by motor proteins along the microtubule cytoskeleton. Microtubule post-translational modifications (PTMs) can contribute to microtubule diversity and differentially regulate motor-mediated transport. Here, we show that centrosome amplification, commonly observed in cancer and shown to promote aneuploidy and invasion, induces a global change in organelle positioning towards the cell periphery and facilitates nuclear migration through confined spaces. This reorganization requires kinesin-1 and is analogous to the loss of dynein. Cells with amplified centrosomes display increased levels of acetylated tubulin, a PTM that could enhance kinesin-1-mediated transport. Depletion of α-tubulin acetyltransferase 1 (αTAT1) to block tubulin acetylation rescues the displacement of centrosomes, mitochondria, and vimentin but not Golgi or endosomes. Analyses of the distribution of total and acetylated microtubules indicate that the polarized distribution of modified microtubules, rather than levels alone, plays an important role in the positioning of specific organelles, such as the centrosome. We propose that increased tubulin acetylation differentially impacts kinesin-1-mediated organelle displacement to regulate intracellular organization.
Asunto(s)
Cinesinas , Tubulina (Proteína) , Tubulina (Proteína)/metabolismo , Cinesinas/genética , Cinesinas/metabolismo , Acetilación , Microtúbulos/metabolismo , Centrosoma/metabolismo , Dineínas/metabolismo , Procesamiento Proteico-PostraduccionalRESUMEN
Germinal centers (GCs) are sites of intense B cell proliferation and are central for T cell-dependent antibody responses. However, the role of c-Myc, a key cell-cycle regulator, in this process has been questioned. Here we identified c-Myc(+) B cell subpopulations in immature and mature GCs and found, by genetic ablation of Myc, that they had indispensable roles in the formation and maintenance of GCs. The identification of these functionally critical cellular subsets has implications for human B cell lymphomagenesis, which originates mostly from GC B cells and frequently involves MYC chromosomal translocations. As these translocations are generally dependent on transcription of the recombining partner loci, the c-Myc(+) GC subpopulations may be at a particularly high risk for malignant transformation.
Asunto(s)
Subgrupos de Linfocitos B/inmunología , Linfocitos B/metabolismo , Ciclo Celular/genética , Centro Germinal/metabolismo , Proteínas Proto-Oncogénicas c-myc/genética , Animales , Linfocitos B/inmunología , Linfocitos B/patología , Ciclo Celular/inmunología , Proliferación Celular , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/inmunología , Eliminación de Gen , Regulación de la Expresión Génica/inmunología , Genes Reporteros , Sitios Genéticos , Centro Germinal/inmunología , Centro Germinal/patología , Proteínas Fluorescentes Verdes , Linfoma/genética , Linfoma/metabolismo , Linfoma/patología , Ratones , Ratones Transgénicos , Proteínas Proto-Oncogénicas c-myc/deficiencia , Proteínas Proto-Oncogénicas c-myc/inmunología , Transducción de Señal/genética , Transducción de Señal/inmunología , Linfocitos T/inmunología , Linfocitos T/metabolismo , Linfocitos T/patología , Translocación GenéticaRESUMEN
Centrosome amplification has long been recognized as a feature of human tumours; however, its role in tumorigenesis remains unclear. Centrosome amplification is poorly tolerated by non-transformed cells and, in the absence of selection, extra centrosomes are spontaneously lost. Thus, the high frequency of centrosome amplification, particularly in more aggressive tumours, raises the possibility that extra centrosomes could, in some contexts, confer advantageous characteristics that promote tumour progression. Using a three-dimensional model system and other approaches to culture human mammary epithelial cells, we find that centrosome amplification triggers cell invasion. This invasive behaviour is similar to that induced by overexpression of the breast cancer oncogene ERBB2 (ref. 4) and indeed enhances invasiveness triggered by ERBB2. Our data indicate that, through increased centrosomal microtubule nucleation, centrosome amplification increases Rac1 activity, which disrupts normal cell-cell adhesion and promotes invasion. These findings demonstrate that centrosome amplification, a structural alteration of the cytoskeleton, can promote features of malignant transformation.
Asunto(s)
Neoplasias de la Mama/patología , Transformación Celular Neoplásica/patología , Centrosoma/patología , Genes erbB-2 , Aneuploidia , Mama/citología , Mama/patología , Neoplasias de la Mama/genética , Adhesión Celular , Línea Celular , Transformación Celular Neoplásica/genética , Progresión de la Enfermedad , Activación Enzimática , Células Epiteliales/citología , Células Epiteliales/patología , Humanos , Microtúbulos/química , Microtúbulos/metabolismo , Microtúbulos/patología , Invasividad Neoplásica/patología , Receptor ErbB-2/genética , Receptor ErbB-2/metabolismo , Proteína de Unión al GTP rac1/metabolismoRESUMEN
Tandemly repeated ribosomal DNA (rDNA) arrays are among the most evolutionary dynamic loci of eukaryotic genomes. The loci code for essential cellular components, yet exhibit extensive copy number (CN) variation within and between species. CN might be partly determined by the requirement of dosage balance between the 5S and 45S rDNA arrays. The arrays are nonhomologous, physically unlinked in mammals, and encode functionally interdependent RNA components of the ribosome. Here we show that the 5S and 45S rDNA arrays exhibit concerted CN variation (cCNV). Despite 5S and 45S rDNA elements residing on different chromosomes and lacking sequence similarity, cCNV between these loci is strong, evolutionarily conserved in humans and mice, and manifested across individual genotypes in natural populations and pedigrees. Finally, we observe that bisphenol A induces rapid and parallel modulation of 5S and 45S rDNA CN. Our observations reveal a novel mode of genome variation, indicate that natural selection contributed to the evolution and conservation of cCNV, and support the hypothesis that 5S CN is partly determined by the requirement of dosage balance with the 45S rDNA array. We suggest that human disease variation might be traced to disrupted rDNA dosage balance in the genome.
Asunto(s)
Variaciones en el Número de Copia de ADN/genética , ADN Ribosómico/genética , Genoma/genética , Animales , Compuestos de Bencidrilo/toxicidad , Cromosomas Humanos Par 1/genética , Variaciones en el Número de Copia de ADN/efectos de los fármacos , Femenino , Sitios Genéticos , Genoma Humano/genética , Genotipo , Humanos , Masculino , Ratones , Linaje , Fenoles/toxicidad , Polimorfismo de Nucleótido Simple/genética , ARN Ribosómico/genética , ARN Ribosómico 5S/genéticaRESUMEN
The presence of supernumerary centrosomes is a hallmark of human tumours. Recent work in animal models suggests that extra centrosomes are not just bystanders in cancer but can accelerate tumourigenesis in the absence of the tumour suppressor p53. Centrosome amplification could indeed actively participate in tumour progression through the induction of chromosome instability, disruption of tissue architecture and promoting cell invasion. Paradoxically, however, centrosome amplification is rather poorly tolerated in normal cells and there are several hurdles cells need to overcome in order to efficiently proliferate in the presence of extra centrosomes. Here, we review the adaptation mechanisms that allow cells to efficiently divide in the presence of extra centrosomes and how these could be exploited to develop selective cancer therapies.
Asunto(s)
Proliferación Celular , Transformación Celular Neoplásica/patología , Centrosoma/patología , Mitosis , Neoplasias/patología , Animales , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/metabolismo , Centrosoma/metabolismo , Inestabilidad Cromosómica , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias/genética , Neoplasias/metabolismo , Transducción de SeñalRESUMEN
Chromosomal instability (CIN) is a hallmark of many tumours and correlates with the presence of extra centrosomes. However, a direct mechanistic link between extra centrosomes and CIN has not been established. It has been proposed that extra centrosomes generate CIN by promoting multipolar anaphase, a highly abnormal division that produces three or more aneuploid daughter cells. Here we use long-term live-cell imaging to demonstrate that cells with multiple centrosomes rarely undergo multipolar cell divisions, and the progeny of these divisions are typically inviable. Thus, multipolar divisions cannot explain observed rates of CIN. In contrast, we observe that CIN cells with extra centrosomes routinely undergo bipolar cell divisions, but display a significantly increased frequency of lagging chromosomes during anaphase. To define the mechanism underlying this mitotic defect, we generated cells that differ only in their centrosome number. We demonstrate that extra centrosomes alone are sufficient to promote chromosome missegregation during bipolar cell division. These segregation errors are a consequence of cells passing through a transient 'multipolar spindle intermediate' in which merotelic kinetochore-microtubule attachment errors accumulate before centrosome clustering and anaphase. These findings provide a direct mechanistic link between extra centrosomes and CIN, two common characteristics of solid tumours. We propose that this mechanism may be a common underlying cause of CIN in human cancer.
Asunto(s)
Centrosoma/fisiología , Inestabilidad Cromosómica/fisiología , Anafase , Línea Celular Tumoral , Segregación Cromosómica , Humanos , Cinetocoros/metabolismo , Microtúbulos/metabolismo , Modelos Biológicos , Neoplasias/genética , Neoplasias/patología , Huso Acromático/metabolismo , Factores de TiempoRESUMEN
Centrioles are microtubule-derived structures that are essential for the formation of centrosomes, cilia and flagella. The centrosome is the major microtubule organiser in animal cells, participating in a variety of processes, from cell polarisation to cell division, whereas cilia and flagella contribute to several mechanisms in eukaryotic cells, from motility to sensing. Although it was suggested more than a century ago that these microtubule-derived structures are involved in human disease, the molecular bases of this association have only recently been discovered. Surprisingly, there is very little overlap between the genes affected in the different diseases, suggesting that there are tissue-specific requirements for these microtubule-derived structures. Knowledge of these requirements and disease mechanisms has opened new avenues for therapeutical strategies. Here, we give an overview of recent developments in this field, focusing on cancer, diseases of brain development and ciliopathies.
Asunto(s)
Centrosoma/fisiología , Cilios/fisiología , Microcefalia/patología , Neoplasias/patología , Aneuploidia , División Celular , Inestabilidad Cromosómica , Humanos , Enfermedades Renales Quísticas/patología , Mutación , Transducción de Señal , Huso Acromático/fisiologíaRESUMEN
Overexpression of the HER2 protein in breast cancer patients is a predictor of poor prognosis and resistance to therapies. We used an inducible breast cancer transformation system that allows investigation of early molecular changes. HER2 overexpression to similar levels as those observed in a subtype of HER2-positive breast cancer patients induced transformation of MCF10A cells and resulted in gross morphological changes, increased anchorage-independent growth of cells, and altered the transcriptional programme of genes associated with oncogenic transformation. Global phosphoproteomic analysis during HER2 induction predominantly detected an increase in protein phosphorylation. Intriguingly, this correlated with chromatin opening, as measured by ATAC-seq on acini isolated from 3D cell culture. HER2 overexpression resulted in opening of many distal regulatory regions and promoted reprogramming-associated heterogeneity. We found that a subset of cells acquired a dedifferentiated breast stem-like phenotype, making them likely candidates for malignant transformation. Our data show that this population of cells, which counterintuitively enriches for relatively low HER2 protein abundance and increased chromatin accessibility, possesses transformational drive, resulting in increased anchorage-independent growth in vitro compared to cells not displaying a stem-like phenotype.
Asunto(s)
Cromatina , Receptor ErbB-2 , Humanos , Receptor ErbB-2/genética , Proliferación Celular , Transformación Celular Neoplásica/genética , Epitelio/metabolismo , Línea Celular Tumoral , Regulación Neoplásica de la Expresión GénicaRESUMEN
T cell activation is associated with a profound and rapid metabolic response to meet increased energy demands for cell division, differentiation and development of effector function. Glucose uptake and engagement of the glycolytic pathway are major checkpoints for this event. Here we show that the low-affinity, concentration-dependent glucose transporter 2 (Glut2) regulates the development of CD8+ T cell effector responses in mice by promoting glucose uptake, glycolysis and glucose storage. Expression of Glut2 is modulated by environmental factors including glucose and oxygen availability and extracellular acidification. Glut2 is highly expressed by circulating, recently primed T cells, allowing efficient glucose uptake and storage. In glucose-deprived inflammatory environments, Glut2 becomes downregulated, thus preventing passive loss of intracellular glucose. Mechanistically, Glut2 expression is regulated by a combination of molecular interactions involving hypoxia-inducible factor-1 alpha, galectin-9 and stomatin. Finally, we show that human T cells also rely on this glucose transporter, thus providing a potential target for therapeutic immunomodulation.
Asunto(s)
Proteínas Facilitadoras del Transporte de la Glucosa , Glucosa , Ratones , Humanos , Animales , Glucosa/metabolismo , Transporte Biológico/fisiología , Proteínas Facilitadoras del Transporte de la Glucosa/genética , Proteínas Facilitadoras del Transporte de la Glucosa/metabolismo , Diferenciación Celular , Linfocitos T CD8-positivos/metabolismoRESUMEN
Correct segregation of chromosomes during mitosis is essential to prevent aneuploidy. In this issue, Ferrandiz et al. (2022. J. Cell Biol.https://doi.org/10.1083/jcb.202203021) show that endomembranes can promote chromosome missegregation by "ensheathing" misaligned chromosomes, preventing their integration into the metaphase plate. Their findings point toward endomembranes as a potential risk factor for aneuploidy.
Asunto(s)
Membrana Celular , Segregación Cromosómica , Cromosomas , Aneuploidia , Cromosomas/genética , Retículo Endoplásmico , Humanos , Metafase , MitosisRESUMEN
Bidirectional communication between cells and their surrounding environment is critical in both normal and pathological settings. Extracellular vesicles (EVs), which facilitate the horizontal transfer of molecules between cells, are recognized as an important constituent of cell-cell communication. In cancer, alterations in EV secretion contribute to the growth and metastasis of tumor cells. However, the mechanisms underlying these changes remain largely unknown. Here, we show that centrosome amplification is associated with and sufficient to promote small extracellular vesicle (SEV) secretion in pancreatic cancer cells. This is a direct result of lysosomal dysfunction, caused by increased reactive oxygen species (ROS) downstream of extra centrosomes. We propose that defects in lysosome function could promote multivesicular body fusion with the plasma membrane, thereby enhancing SEV secretion. Furthermore, we find that SEVs secreted in response to amplified centrosomes are functionally distinct and activate pancreatic stellate cells (PSCs). These activated PSCs promote the invasion of pancreatic cancer cells in heterotypic 3D cultures. We propose that SEVs secreted by cancer cells with amplified centrosomes influence the bidirectional communication between the tumor cells and the surrounding stroma to promote malignancy.
Asunto(s)
Centrosoma , Vesículas Extracelulares , Lisosomas , Animales , Vesículas Extracelulares/metabolismo , Humanos , Ratones , Cuerpos Multivesiculares , Neoplasias Pancreáticas/patología , Neoplasias PancreáticasRESUMEN
Precise control of centrosome number is crucial for bipolar spindle assembly and accurate transmission of genetic material to daughter cells. Failure to properly control centrosome number results in supernumerary centrosomes, which are frequently found in cancer cells. This presents a paradox: during mitosis, cells with more than two centrosomes are prone to multipolar mitoses and cell death, however, cancer cells possessing extra centrosomes usually divide successfully. One mechanism frequently utilized by cancer cells to escape death caused by multipolar mitoses is the clustering of supernumerary centrosomes into bipolar arrays. An understanding of the molecular mechanisms by which cancer cells can suppress multipolar mitoses is beginning to emerge. Here, we review what's currently known about centrosome clustering mechanisms and discuss potential strategies to target these mechanisms for the selective killing of cancer cells.
Asunto(s)
Centrosoma/ultraestructura , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patología , Animales , Adhesión Celular , División Celular , Transformación Celular Neoplásica/genética , Genoma , Humanos , Mitosis , Modelos Biológicos , Ploidias , Transducción de Señal , Huso AcromáticoRESUMEN
During obesity, macrophages infiltrate the breast tissue leading to low-grade chronic inflammation, a factor considered responsible for the higher risk of breast cancer associated with obesity. Here, we formally demonstrate that breast epithelial cells acquire malignant properties when exposed to medium conditioned by macrophages derived from human healthy donors. These effects were mediated by the breast cancer oncogene IKKε and its downstream target-the serine biosynthesis pathway as demonstrated by genetic or pharmacological tools. Furthermore, amlexanox, an FDA-approved drug targeting IKKε and its homologue TBK1, delayed in vivo tumour formation in a combined genetic mouse model of breast cancer and high-fat diet-induced obesity/inflammation. Finally, in human breast cancer tissues, we validated the link between inflammation-IKKε and alteration of cellular metabolism. Altogether, we identified a pathway connecting obesity-driven inflammation to breast cancer and a potential therapeutic strategy to reduce the risk of breast cancer associated with obesity.
Asunto(s)
Neoplasias de la Mama/patología , Quinasa I-kappa B , Macrófagos/citología , Proteínas Serina-Treonina Quinasas/metabolismo , Serina , Aminopiridinas/farmacología , Animales , Medios de Cultivo Condicionados , Células Epiteliales/patología , Femenino , Humanos , Quinasa I-kappa B/metabolismo , Inflamación , Glándulas Mamarias Humanas/patología , Ratones , Obesidad , Serina/biosíntesisRESUMEN
Structural centrosomal aberrations have long been described in cancer, but their impact on cell physiology and tumorigenesis remains unclear. Ganier et al. (2018) show that centrosome structural abnormalities facilitate cell dissemination by promoting budding of epithelial mitotic cells.
Asunto(s)
División Celular , Centrosoma , Recuento de Células , Transformación Celular Neoplásica , Células Epiteliales , HumanosRESUMEN
Centrosome amplification is a common feature of human tumors. To survive, cancer cells cluster extra centrosomes during mitosis, avoiding the detrimental effects of multipolar divisions. However, it is unclear whether clustering requires adaptation or is inherent to all cells. Here, we show that cells have varied abilities to cluster extra centrosomes. Epithelial cells are innately inefficient at clustering even in the presence of HSET/KIFC1, which is essential but not sufficient to promote clustering. The presence of E-cadherin decreases cortical contractility during mitosis through a signaling cascade leading to multipolar divisions, and its knockout promotes clustering and survival of cells with multiple centrosomes. Cortical contractility restricts centrosome movement at a minimal distance required for HSET/KIFC1 to exert its function, highlighting a biphasic model for centrosome clustering. In breast cancer cell lines, increased levels of centrosome amplification are accompanied by efficient clustering and loss of E-cadherin, indicating that this is an important adaptation mechanism to centrosome amplification in cancer.
Asunto(s)
Neoplasias de la Mama/patología , Cadherinas/genética , Centrosoma/metabolismo , Receptor con Dominio Discoidina 1/genética , Células Epiteliales/patología , Comunicación Celular/genética , Comunicación Celular/fisiología , Línea Celular Tumoral , Femenino , Humanos , Cinesinas/metabolismo , Mitosis/genéticaRESUMEN
Centrosomal abnormalities, in particular centrosome amplification, are recurrent features of human tumors. Enforced centrosome amplification in vivo plays a role in tumor initiation and progression. However, centrosome amplification occurs only in a subset of cancer cells, and thus, partly due to this heterogeneity, the contribution of centrosome amplification to tumors is unknown. Here, we show that supernumerary centrosomes induce a paracrine-signaling axis via the secretion of proteins, including interleukin-8 (IL-8), which leads to non-cell-autonomous invasion in 3D mammary organoids and zebrafish models. This extra centrosomes-associated secretory phenotype (ECASP) promotes invasion of human mammary cells via HER2 signaling activation. Further, we demonstrate that centrosome amplification induces an early oxidative stress response via increased NOX-generated reactive oxygen species (ROS), which in turn mediates secretion of pro-invasive factors. The discovery that cells with extra centrosomes can manipulate the surrounding cells highlights unexpected and far-reaching consequences of these abnormalities in cancer.
Asunto(s)
Transformación Celular Neoplásica/patología , Centrosoma/patología , Mitosis/fisiología , Estrés Oxidativo/fisiología , Mama/metabolismo , Mama/patología , Centrosoma/metabolismo , Humanos , Neoplasias/patología , Transducción de Señal/fisiologíaRESUMEN
Centrosomes are the major microtubule organising centres of animal cells. Deregulation in their number occurs in cancer and was shown to trigger tumorigenesis in mice. However, the incidence, consequence and origins of this abnormality are poorly understood. Here, we screened the NCI-60 panel of human cancer cell lines to systematically analyse centriole number and structure. Our screen shows that centriole amplification is widespread in cancer cell lines and highly prevalent in aggressive breast carcinomas. Moreover, we identify another recurrent feature of cancer cells: centriole size deregulation. Further experiments demonstrate that severe centriole over-elongation can promote amplification through both centriole fragmentation and ectopic procentriole formation. Furthermore, we show that overly long centrioles form over-active centrosomes that nucleate more microtubules, a known cause of invasiveness, and perturb chromosome segregation. Our screen establishes centriole amplification and size deregulation as recurrent features of cancer cells and identifies novel causes and consequences of those abnormalities.
Asunto(s)
Centriolos/metabolismo , Cromosomas/ultraestructura , Neoplasias/genética , Neoplasias/metabolismo , Automatización , Neoplasias de la Mama/metabolismo , Ciclo Celular/fisiología , Proteínas de Ciclo Celular/metabolismo , Línea Celular Tumoral , Centrosoma/metabolismo , Humanos , Microscopía Electrónica de Transmisión , Proteínas Asociadas a Microtúbulos/metabolismo , Microtúbulos/metabolismo , Mitosis , Ploidias , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
Centrosome numbers are tightly regulated during the cell cycle. A new study shows that the PIDDosome prevents the propagation of cells carrying amplified centrosomes via p53 stabilisation and p21-mediated cell-cycle arrest, thus ensuring the maintenance of normal centrosome numbers.
Asunto(s)
Centrosoma , Proteína p53 Supresora de Tumor , Ciclo Celular , Puntos de Control del Ciclo CelularRESUMEN
Despite being a common feature of human cancer, the role of supernumerary centrosomes in tumourigenesis is still poorly understood. We have recently described a novel role for centrosome amplification in promoting cell invasion that could impact tumor progression.