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During embryonic development the placental vasculature acts as a major hematopoietic niche, where endothelial to hematopoietic transition ensures emergence of hematopoietic stem cells (HSCs). However, the molecular mechanisms that regulate the placental hematoendothelial niche are poorly understood. Using a parietal trophoblast giant cell (TGC)-specific knockout mouse model and single-cell RNA-sequencing, we show that the paracrine factors secreted by the TGCs are critical in the development of this niche. Disruptions in the TGC-specific paracrine signaling leads to the loss of HSC population and the concomitant expansion of a KDR+/DLL4+/PROM1+ hematoendothelial cell-population in the placenta. Combining single-cell transcriptomics and receptor-ligand pair analyses, we also define the parietal TGC-dependent paracrine signaling network and identify Integrin signaling as a fundamental regulator of this process. Our study elucidates novel mechanisms by which non-autonomous signaling from the primary parietal TGCs maintain the delicate placental hematopoietic-angiogenic balance and ensures embryonic and extraembryonic development.
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The therapeutic potential of targeting the ß-catenin/CBP interaction has been demonstrated in a variety of preclinical tumor models with a small molecule inhibitor, ICG-001, characterized as a ß-catenin/CBP antagonist. Despite the high binding specificity of ICG-001 for the N-terminus of CBP, this ß-catenin/CBP antagonist exhibits pleiotropic effects. Our recent studies found global changes in three-dimensional (3D) chromatin architecture in response to disruption of the ß-catenin/CBP interaction in pancreatic cancer cells. However, an understanding of how the functional crosstalk between the antagonist and the ß-catenin/CBP interaction affects changes in 3D chromatin architecture and, thereby, gene expression and downstream effects remains to be elucidated. Here, we perform Hi-C analyses on canonical and patient-derived pancreatic cancer cells before and after treatment with ICG-001. In addition to global alteration of 3D chromatin domains, we unexpectedly identify insulin signaling genes enriched in the altered chromatin domains. We further demonstrate that the chromatin loops associated with insulin signaling genes are significantly weakened after ICG-001 treatment. We finally elicit the deletion of a looping of IRS1-a key insulin signaling gene-significantly impeding pancreatic cancer cell growth, indicating that looping-mediated insulin signaling might act as an oncogenic pathway to promote pancreatic cancer progression. Our work shows that targeting aberrant insulin chromatin looping in pancreatic cancer might provide a therapeutic benefit.
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The six subunit Origin Recognition Complex (ORC) is essential for loading MCM2-7 at origins of DNA replication to promote initiation of DNA replication in organisms ranging from S. cerevisiae to humans. In rare instances, as in cancer cell-lines in culture with mutations in ORC1 , ORC2 or ORC5 , or in endo-reduplicating mouse hepatocytes in vivo without ORC1 , DNA replication has been observed in the virtual absence of individual ORC subunits. Although ORC1 is dispensable in the mouse liver for endo-reduplication, because of the homology of ORC1 with CDC6, it could be argued that CDC6 was substituting for ORC1 to restore functional ORC. Here, we have created mice with a conditional deletion of ORC2 , to demonstrate that mouse embryo fibroblasts require ORC2 for proliferation, but that the mouse hepatocytes can carry out DNA synthesis in vitro and endo-reduplicate in vivo , despite the deletion of ORC2 . Combining the conditional mutation of ORC1 and ORC2 revealed that the mouse liver can still carry out endo-reduplication despite the deletion of the two genes, both during normal development and after partial hepatectomy. Since endo-reduplication, like normal S phase replication, requires the presence of MCM2-7 on the chromatin, these results suggest that in primary hepatocytes there is a mechanism to load sufficient MCM2-7 to carry out effective DNA replication despite the virtual absence of two subunits of ORC.
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The therapeutic potential of targeting the ß-catenin/CBP interaction has been demonstrated in a variety of preclinical tumor models with a small molecule inhibitor, ICG-001, characterized as a ß-catenin/CBP antagonist. Despite the high binding specificity of ICG-001 for the N-terminus of CBP, this ß-catenin/CBP antagonist exhibits pleiotropic effects. Our recent studies found global changes in three-dimensional (3D) chromatin architecture in response to disruption of the ß-catenin/CBP interaction in pancreatic cancer cells. However, an understanding of the functional crosstalk between antagonizing the ß-catenin/CBP interaction effect changes in 3D chromatin architecture and thereby gene expression and downstream effects remains to be elucidated. Here we perform Hi-C analyses on canonical and patient-derived pancreatic cancer cells before and after the treatment with ICG-001. In addition to global alteration of 3D chromatin domains, we unexpectedly identify insulin signaling genes enriched in the altered chromatin domains. We further demonstrate the chromatin loops associated with insulin signaling genes are significantly weakened after ICG-001 treatment. We finally elicit the deletion of a looping of IRS1, a key insulin signaling gene, significantly impede pancreatic cancer cell growth, indicating that looping-mediated insulin signaling might act as an oncogenic pathway to promote pancreatic cancer progression. Our work shows that targeting aberrant insulin chromatin looping in pancreatic cancer might provide a therapeutic benefit.
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Cancer is the leading cause of mortality in U.S. Latino adults, a group with limited access to screening, higher rates of advanced disease, and prone to online misinformation. Our project created a Facebook Live social media video campaign on general cancer prevention, screening, risk, information, and resources, targeting Spanish-monolingual Latinos during the COVID-19 pandemic. Content was delivered in Spanish by fluent, ethnically concordant topic experts and cancer center staff. Four prerecorded and three livestream interview videos were produced, amassing over 161 shares, 1,000 engagements, 12,000 views, 19,000 people reached, and 34,000 impressions in a span of four months. Strengths of this project included developing community partnerships and collaborations, providing evidence-based cancer information in a culturally responsive manner to often-excluded community members during COVID-19 pandemic, and presenting our cancer center as an accessible resource to the wider community. Future directions include formalizing evaluation strategies to capture medical engagement via cancer screening and detection rates, delivering focused cancer discussions by disease sites, and further expanding audience base through mixed media formats.
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Promoción de la Salud , Neoplasias , Medios de Comunicación Sociales , Humanos , Comunicación , COVID-19 , Hispánicos o Latinos , Neoplasias/diagnóstico , Neoplasias/epidemiología , Neoplasias/prevención & control , PandemiasRESUMEN
Pancreatic cancer is characterized by abundant desmoplasia, a dense stroma composed of extra-cellular and cellular components, with cancer associated fibroblasts (CAFs) being the major cellular component. However, the tissue(s) of origin for CAFs remains controversial. Here we determine the tissue origin of pancreatic CAFs through comprehensive lineage tracing studies in mice. We find that the splanchnic mesenchyme, the fetal cell layer surrounding the endoderm from which the pancreatic epithelium originates, gives rise to the majority of resident fibroblasts in the normal pancreas. In a genetic mouse model of pancreatic cancer, resident fibroblasts expand and constitute the bulk of CAFs. Single cell RNA profiling identifies gene expression signatures that are shared among the fetal splanchnic mesenchyme, adult fibroblasts and CAFs, suggesting a persistent transcriptional program underlies splanchnic lineage differentiation. Together, this study defines the phylogeny of the mesenchymal component of the pancreas and provides insights into pancreatic morphogenesis and tumorigenesis.
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Páncreas , Neoplasias Pancreáticas , Ratones , Animales , Páncreas/metabolismo , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Fibroblastos/metabolismo , Carcinogénesis/genética , Carcinogénesis/metabolismo , Transformación Celular Neoplásica/metabolismo , Mesodermo/metabolismo , Homeostasis , Neoplasias PancreáticasAsunto(s)
Diploidia , Miocitos Cardíacos , Humanos , Factores de Transcripción E2F , Infarto , Regeneración , Proliferación CelularRESUMEN
Long-term maintenance of the adult neurogenic niche depends on proper regulation of entry and exit from quiescence. Neural stem cell (NSC) transition from quiescence to activation is a complex process requiring precise cell-cycle control coordinated with transcriptional and morphological changes. How NSC fate transitions in coordination with the cell-cycle machinery remains poorly understood. Here we show that the Rb/E2F axis functions by linking the cell-cycle machinery to pivotal regulators of NSC fate. Deletion of Rb family proteins results in activation of NSCs, inducing a transcriptomic transition toward activation. Deletion of their target activator E2Fs1/3 results in intractable quiescence and cessation of neurogenesis. We show that the Rb/E2F axis mediates these fate transitions through regulation of factors essential for NSC function, including REST and ASCL1. Thus, the Rb/E2F axis is an important regulator of NSC fate, coordinating cell-cycle control with NSC activation and quiescence fate transitions.
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Células Madre Adultas , Células-Madre Neurales , Células-Madre Neurales/metabolismo , Células Madre Adultas/metabolismo , Neurogénesis/fisiología , División Celular , Ciclo Celular , Proteína de Retinoblastoma/genética , Proteína de Retinoblastoma/metabolismoRESUMEN
Communication between mesodermal cells and epithelial cells is fundamental to normal animal development and is frequently disrupted in cancer. However, the genes and processes that mediate this communication are incompletely understood. To identify genes that mediate this communication and alter the proliferation of cells with an oncogenic Ras genotype, we carried out a tissue-specific genome-wide RNAi screen in Caenorhabditis elegans animals bearing a let-60(n1046gf) (RasG13E) allele. The screen identifies 24 genes that, when knocked down in adjacent mesodermal tissue, suppress the increased vulval epithelial cell proliferation defect associated with let-60(n1046gf). Importantly, gene knockdown reverts the mutant animals to a wild-type phenotype. Using chimeric animals, we genetically confirm that 2 of the genes function nonautonomously to revert the let-60(n1046gf) phenotype. The effect is genotype restricted, as knockdown does not alter development in a wild type (let-60(+)) or activated EGF receptor (let-23(sa62gf)) background. Although many of the genes identified encode proteins involved in essential cellular processes, including chromatin formation, ribosome function, and mitochondrial ATP metabolism, knockdown does not alter the normal development or function of targeted mesodermal tissues, indicating that the phenotype derives from specific functions performed by these cells. We show that the genes act in a manner distinct from 2 signal ligand classes (EGF and Wnt) known to influence the development of vulval epithelial cells. Altogether, the results identify genes with a novel function in mesodermal cells required for communicating with and promoting the proliferation of adjacent epithelial cells with an activated Ras genotype.
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Proteínas de Caenorhabditis elegans , Adenosina Trifosfato/metabolismo , Animales , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Cromatina/metabolismo , Factor de Crecimiento Epidérmico/genética , Factor de Crecimiento Epidérmico/metabolismo , Receptores ErbB/genética , Femenino , Proteínas del Helminto/genética , Ligandos , Mutación , Transducción de Señal/genética , Vulva/metabolismo , Proteínas ras/genética , Proteínas ras/metabolismoRESUMEN
Pancreatic ductal adenocarcinoma (PDAC) is associated with an incredibly dense stroma, which contributes to its recalcitrance to therapy. Cancer-associated fibroblasts (CAFs) are one of the most abundant cell types within the PDAC stroma and have context-dependent regulation of tumor progression in the tumor microenvironment (TME). Therefore, understanding tumor-promoting pathways in CAFs is essential for developing better stromal targeting therapies. Here, we show that disruption of the STAT3 signaling axis via genetic ablation of Stat3 in stromal fibroblasts in a Kras G12D PDAC mouse model not only slows tumor progression and increases survival, but re-shapes the characteristic immune-suppressive TME by decreasing M2 macrophages (F480+CD206+) and increasing CD8+ T cells. Mechanistically, we show that loss of the tumor suppressor PTEN in pancreatic CAFs leads to an increase in STAT3 phosphorylation. In addition, increased STAT3 phosphorylation in pancreatic CAFs promotes secretion of CXCL1. Inhibition of CXCL1 signaling inhibits M2 polarization in vitro. The results provide a potential mechanism by which CAFs promote an immune-suppressive TME and promote tumor progression in a spontaneous model of PDAC.
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Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Animales , Linfocitos T CD8-positivos/metabolismo , Carcinoma Ductal Pancreático/metabolismo , Línea Celular Tumoral , Fibroblastos/metabolismo , Ratones , Neoplasias Pancreáticas/metabolismo , Microambiente Tumoral , Neoplasias PancreáticasRESUMEN
Coevolution of tumor cells and adjacent stromal elements is a key feature during tumor progression; however, the precise regulatory mechanisms during this process remain unknown. Here, we show stromal p53 loss enhances oncogenic KrasG12D, but not ErbB2, driven tumorigenesis in murine mammary epithelia. Stroma-specific p53 deletion increases both epithelial and fibroblast proliferation in mammary glands bearing the KrasG12D oncogene in epithelia, while concurrently increasing DNA damage and/or DNA replication stress and decreasing apoptosis in the tumor cells proper. Normal epithelia was not affected by stromal p53 deletion. Tumors with p53-null stroma had a significant decrease in total, cytotoxic, and regulatory T cells; however, there was a significant increase in myeloid-derived suppressor cells, total macrophages, and M2-polarized tumor-associated macrophages, with no impact on angiogenesis or connective tissue deposition. Stroma-specific p53 deletion reprogrammed gene expression in both fibroblasts and adjacent epithelium, with p53 targets and chemokine receptors/chemokine signaling pathways in fibroblasts and DNA replication, DNA damage repair, and apoptosis in epithelia being the most significantly impacted biological processes. A gene cluster in p53-deficient mouse fibroblasts was negatively associated with patient survival when compared with two independent datasets. In summary, stroma-specific p53 loss promotes mammary tumorigenesis in an oncogene-specific manner, influences the tumor immune landscape, and ultimately impacts patient survival. IMPLICATIONS: Expression of the p53 tumor suppressor in breast cancer tumor stroma regulates tumorigenesis in an oncogene-specific manner, influences the tumor immune landscape, and ultimately impacts patient survival.
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Neoplasias de la Mama , Oncogenes , Proteína p53 Supresora de Tumor , Animales , Neoplasias de la Mama/genética , Neoplasias de la Mama/inmunología , Carcinogénesis , Tejido Conectivo/metabolismo , Ratones , Proteínas Proto-Oncogénicas p21(ras) , Células del Estroma/patología , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
Pancreas and breast cancers both contain abundant stromal components within the tumor tissues. A prominent cell type within the stroma is cancer-associated fibroblasts (CAFs). CAFs play critical and complex roles establishing the tumor microenvironment to either promote or prevent tumor progression. Recently, complex genetic models and single cell-based techniques have provided emerging insights on the precise functions and cellular heterogeneity of CAFs. The transformation of normal fibroblasts into CAFs is a key event during tumor initiation and progression. Such coordination between tumor cells and fibroblasts plays an important role in cancer development. Reprograming fibroblasts is currently being explored for therapeutic benefits. In this review, we will discuss recent literature shedding light on the tissues of origin, activation mechanisms, and heterogeneity of CAFs comparing pancreas and breast cancers.
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Neoplasias de la Mama , Fibroblastos Asociados al Cáncer , Neoplasias de la Mama/patología , Fibroblastos Asociados al Cáncer/patología , Femenino , Fibroblastos/metabolismo , Fibroblastos/patología , Humanos , Páncreas/patología , Microambiente TumoralRESUMEN
Automatic characterization of fluorescent labeling in intact mammalian tissues remains a challenge due to the lack of quantifying techniques capable of segregating densely packed nuclei and intricate tissue patterns. Here, we describe a powerful deep learning-based approach that couples remarkably precise nuclear segmentation with quantitation of fluorescent labeling intensity within segmented nuclei, and then apply it to the analysis of cell cycle dependent protein concentration in mouse tissues using 2D fluorescent still images. First, several existing deep learning-based methods were evaluated to accurately segment nuclei using different imaging modalities with a small training dataset. Next, we developed a deep learning-based approach to identify and measure fluorescent labels within segmented nuclei, and created an ImageJ plugin to allow for efficient manual correction of nuclear segmentation and label identification. Lastly, using fluorescence intensity as a readout for protein concentration, a three-step global estimation method was applied to the characterization of the cell cycle dependent expression of E2F proteins in the developing mouse intestine.
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Aprendizaje Profundo , Animales , Ciclo Celular , Proteínas de Ciclo Celular , Núcleo Celular , Procesamiento de Imagen Asistido por Computador/métodos , Mamíferos , RatonesRESUMEN
Nonalcoholic steatohepatitis (NASH) is the progressive form of nonalcoholic fatty liver disease (NAFLD) and is characterized by inflammation, hepatocyte injury, and fibrosis. Further, NASH is a risk factor for cirrhosis and hepatocellular carcinoma. Previous research demonstrated that serum N-glycan profiles can be altered in NASH patients. Here, we hypothesized that these N-glycan modifications may be associated with specific liver damage in NAFLD and NASH. To investigate the N-glycome profile in tissue, imaging mass spectrometry was used for a qualitative and quantitative in situ N-linked glycan analysis of mouse and human NAFLD/NASH tissue. A murine model was used to induce NAFLD and NASH through ad libitum feeding with either a high-fat diet or a Western diet, respectively. Mice fed a high-fat diet or Western diet developed inflammation, steatosis, and fibrosis, consistent with NAFLD/NASH phenotypes. Induction of NAFLD/NASH for 18 months using high caloric diets resulted in increased expression of mannose, complex/fucosylated, and hybrid N-glycan structures compared to control mouse livers. To validate the animal results, liver biopsy specimens from 51 human NAFLD/NASH patients representing the full range of NASH Clinical Research Network fibrosis stages were analyzed. Importantly, the same glycan alterations observed in mouse models were observed in human NASH biopsies and correlated with the degree of fibrosis. In addition, spatial glycan alterations were localized specifically to histopathological changes in tissue like fibrotic and fatty areas. We demonstrate that the use of standard staining's combined with imaging mass spectrometry provide a full profile of the origin of N-glycan modifications within the tissue. These results indicate that the spatial distribution of abundances of released N-glycans correlate with regions of tissue steatosis associated with NAFLD/NASH.
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Neoplasias Hepáticas , Enfermedad del Hígado Graso no Alcohólico , Animales , Dieta Occidental , Modelos Animales de Enfermedad , Glicosilación , Humanos , Inflamación/metabolismo , Hígado/metabolismo , Cirrosis Hepática/genética , Cirrosis Hepática/metabolismo , Cirrosis Hepática/patología , Neoplasias Hepáticas/metabolismo , Espectrometría de Masas , Ratones , Enfermedad del Hígado Graso no Alcohólico/metabolismoRESUMEN
Cyclin D1 is a regulatory subunit of -Cyclin Dependent Kinases 4 and 6 (CDK4/6) and regulates progression from G1 to S phase of the cell cycle. Dysregulated cyclin D1-CDK4/6 contributes to abnormal cell proliferation and tumor development. Phosphorylation of threonine 286 of cyclin D1 is necessary for ubiquitin-dependent degradation. Non-phosphorylatable cyclin D1 mutants are stabilized and concentrated in the nucleus, contributing to genomic instability and tumor development. Studies investigating the tumor-promoting functions of cyclin D1 mutants have focused on the use of artificial promoters to drive the expression which unfortunately may not accurately reflect tumorigenic functions of mutant cyclin D1 in cancer development. We have generated a conditional knock-in mouse model where cyclin D1T286A is expressed under the control of its endogenous promoter following Cre-dependent excision of a lox-stop-lox sequence. Acute expression of cyclin D1T286A following tamoxifen-inducible Cre recombinase triggers inflammation, lymphocyte abnormality and ultimately mesenteric tumors in the intestine. Tissue-specific expression of cyclin D1T286A in the uterus and endometrium cooperates with Pten loss to drive endometrial hyperplasia and cancer. Mechanistically, cyclin D1T286A mutant activates NF-κB signaling, augments inflammation, and contributes to tumor development. These results indicate that mutation of cyclin D1 at threonine 286 has a critical role in regulating inflammation and tumor development.
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Carcinoma , Ciclina D1 , Hiperplasia Endometrial , Fosfohidrolasa PTEN , Animales , Ciclina D1/genética , Ciclina D1/metabolismo , Quinasa 4 Dependiente de la Ciclina/genética , Femenino , Humanos , Inflamación , Ratones , Fosfohidrolasa PTEN/genética , TreoninaRESUMEN
Fragile X-related protein-1 (FXR1) gene is highly amplified in patients with ovarian cancer, and this amplification is associated with increased expression of both FXR1 mRNA and protein. FXR1 expression directly associates with the survival and proliferation of cancer cells. Surface sensing of translation (SUnSET) assay demonstrates that FXR1 enhances the overall translation in cancer cells. Reverse-phase protein array (RPPA) reveals that cMYC is the key target of FXR1. Mechanistically, FXR1 binds to the AU-rich elements (ARE) present within the 3' untranslated region (3'UTR) of cMYC and stabilizes its expression. In addition, the RGG domain in FXR1 interacts with eIF4A1 and eIF4E proteins. These two interactions of FXR1 result in the circularization of cMYC mRNA and facilitate the recruitment of eukaryotic translation initiation factors to the translation start site. In brief, we uncover a mechanism by which FXR1 promotes cMYC levels in cancer cells.
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Factor 4F Eucariótico de Iniciación/metabolismo , Neoplasias Ováricas/metabolismo , Proteínas Proto-Oncogénicas c-myc/metabolismo , Proteínas de Unión al ARN/metabolismo , Regiones no Traducidas 3' , Elementos Ricos en Adenilato y Uridilato , Animales , Línea Celular Tumoral , Proliferación Celular , Supervivencia Celular , Factor 4F Eucariótico de Iniciación/genética , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Ratones Desnudos , Neoplasias Ováricas/genética , Neoplasias Ováricas/patología , Iniciación de la Cadena Peptídica Traduccional , Proteínas Proto-Oncogénicas c-myc/genética , Estabilidad del ARN , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas de Unión al ARN/genética , Transducción de Señal , Carga TumoralRESUMEN
[Figure: see text].
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Síndrome Antifosfolípido/metabolismo , Proteínas Relacionadas con Receptor de LDL/metabolismo , Preeclampsia/metabolismo , Proteína Fosfatasa 2/metabolismo , Trofoblastos/metabolismo , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Anticuerpos Antifosfolípidos/sangre , Síndrome Antifosfolípido/complicaciones , Proteínas Reguladoras de la Apoptosis/metabolismo , Línea Celular , Femenino , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Ratones , Ratones Endogámicos C57BL , Preeclampsia/etiología , EmbarazoRESUMEN
PFKP (phosphofructokinase, platelet), the major isoform of PFK1 expressed in T cell acute lymphoblastic leukemia (T-ALL), is predominantly expressed in the cytoplasm to carry out its glycolytic function. Our study showed that PFKP is a nucleocytoplasmic shuttling protein with functional nuclear export and nuclear localization sequences (NLSs). Cyclin D3/CDK6 facilitated PFKP nuclear translocation by dimerization and by exposing the NLS of PFKP to induce the interaction between PFKP and importin 9. Nuclear PFKP stimulated the expression of C-X-C chemokine receptor type 4 (CXCR4), a chemokine receptor regulating leukemia homing/infiltration, to promote T-ALL cell invasion, which depended on the activity of c-Myc. In vivo experiments showed that nuclear PFKP promoted leukemia homing/infiltration into the bone marrow, spleen, and liver, which could be blocked with CXCR4 antagonists. Immunohistochemical staining of tissues from a clinically well-annotated cohort of T cell lymphoma/leukemia patients showed nuclear PFKP localization in invasive cancers, but not in nonmalignant T lymph node or reactive hyperplasia. The presence of nuclear PFKP in these specimens correlated with poor survival in patients with T cell malignancy, suggesting the potential utility of nuclear PFKP as a diagnostic marker.
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Fosfofructoquinasa-1 Tipo C/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patología , Receptores CXCR4/metabolismo , Transporte Activo de Núcleo Celular , Animales , Biomarcadores de Tumor/metabolismo , Quinasa 6 Dependiente de la Ciclina/metabolismo , Femenino , Humanos , Carioferinas/metabolismo , Linfocitos Infiltrantes de Tumor/metabolismo , Linfocitos Infiltrantes de Tumor/patología , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , Persona de Mediana Edad , Modelos Moleculares , Invasividad Neoplásica/patología , Invasividad Neoplásica/fisiopatología , Fosfofructoquinasa-1 Tipo C/química , Fosfofructoquinasa-1 Tipo C/genética , Pronóstico , Dominios y Motivos de Interacción de Proteínas , Proteínas Proto-Oncogénicas c-myc/metabolismo , Células Tumorales CultivadasRESUMEN
Platelet-derived growth factor receptor-beta (PDGFRß) is a receptor tyrosine kinase found in cells of mesenchymal origin such as fibroblasts and pericytes. Activation of this receptor is dependent on paracrine ligand induction, and its preferred ligand PDGFB is released by neighboring epithelial and endothelial cells. While expression of both PDGFRß and PDGFB has been noted in patient breast tumors for decades, how PDGFB-to-PDGFRß tumor-stroma signaling mediates breast cancer initiation, progression, and metastasis remains unclear. Here we demonstrate this paracrine signaling pathway that mediates both primary tumor growth and metastasis, specifically, metastasis to the brain. Elevated levels of PDGFB accelerated orthotopic tumor growth and intracranial growth of mammary tumor cells, while mesenchymal-specific expression of an activating mutant PDGFRß (PDGFRßD849V) exerted proproliferative signals on adjacent mammary tumor cells. Stromal expression of PDGFRßD849V also promoted brain metastases of mammary tumor cells expressing high PDGFB when injected intravenously. In the brain, expression of PDGFRßD849V was observed within a subset of astrocytes, and aged mice expressing PDGFRßD849V exhibited reactive gliosis. Importantly, the PDGFR-specific inhibitor crenolanib significantly reduced intracranial growth of mammary tumor cells. In a tissue microarray comprised of 363 primary human breast tumors, high PDGFB protein expression was prognostic for brain metastases, but not metastases to other sites. Our results advocate the use of mice expressing PDGFRßD849V in their stromal cells as a preclinical model of breast cancer-associated brain metastases and support continued investigation into the clinical prognostic and therapeutic use of PDGFB-to-PDGFRß signaling in women with breast cancer. SIGNIFICANCE: These studies reveal a previously unknown role for PDGFB-to-PDGFRß paracrine signaling in the promotion of breast cancer brain metastases and support the prognostic and therapeutic clinical utility of this pathway for patients.See related article by Wyss and colleagues, p. 594.