RESUMEN
The acquisition of mesenchymal traits is considered a hallmark of breast cancer progression. However, the functional relevance of epithelial-to-mesenchymal transition (EMT) remains controversial and context dependent. Here, we isolate epithelial and mesenchymal populations from human breast cancer metastatic biopsies and assess their functional potential in vivo. Strikingly, progressively decreasing epithelial cell adhesion molecule (EPCAM) levels correlate with declining disease propagation. Mechanistically, we find that persistent EPCAM expression marks epithelial clones that resist EMT induction and propagate competitively. In contrast, loss of EPCAM defines clones arrested in a mesenchymal state, with concomitant suppression of tumorigenicity and metastatic potential. This dichotomy results from distinct clonal trajectories impacting global epigenetic programs that are determined by the interplay between human ZEB1 and its target GRHL2. Collectively, our results indicate that susceptibility to irreversible EMT restrains clonal propagation, whereas resistance to mesenchymal reprogramming sustains disease spread in multiple models of human metastatic breast cancer, including patient-derived cells in vivo.
Asunto(s)
Neoplasias de la Mama , Humanos , Femenino , Molécula de Adhesión Celular Epitelial , Neoplasias de la Mama/patología , Línea Celular Tumoral , Mama/metabolismo , Células Clonales/metabolismo , Transición Epitelial-MesenquimalRESUMEN
RNA-binding proteins (RBPs) form a large and diverse class of factors, many members of which are overexpressed in hematologic malignancies. RBPs participate in various processes of messenger RNA (mRNA) metabolism and prevent harmful DNA:RNA hybrids or R-loops. Here, we report that PIWIL4, a germ stem cell-associated RBP belonging to the RNase H-like superfamily, is overexpressed in patients with acute myeloid leukemia (AML) and is essential for leukemic stem cell function and AML growth, but dispensable for healthy human hematopoietic stem cells. In AML cells, PIWIL4 binds to a small number of known piwi-interacting RNA. Instead, it largely interacts with mRNA annotated to protein-coding genic regions and enhancers that are enriched for genes associated with cancer and human myeloid progenitor gene signatures. PIWIL4 depletion in AML cells downregulates the human myeloid progenitor signature and leukemia stem cell (LSC)-associated genes and upregulates DNA damage signaling. We demonstrate that PIWIL4 is an R-loop resolving enzyme that prevents R-loop accumulation on a subset of AML and LSC-associated genes and maintains their expression. It also prevents DNA damage, replication stress, and activation of the ATR pathway in AML cells. PIWIL4 depletion potentiates sensitivity to pharmacological inhibition of the ATR pathway and creates a pharmacologically actionable dependency in AML cells.
Asunto(s)
Leucemia Mieloide Aguda , Humanos , Leucemia Mieloide Aguda/patología , Células Madre Hematopoyéticas/metabolismo , Proliferación Celular , Genómica , ARN Mensajero/metabolismo , Células Madre Neoplásicas/patologíaRESUMEN
Pancreatic ductal adenocarcinoma (PDAC) frequently metastasizes into the peritoneum, which contributes to poor prognosis. Metastatic spreading is promoted by cancer cell plasticity, yet its regulation by the microenvironment is incompletely understood. Here, we show that the presence of hyaluronan and proteoglycan link protein-1 (HAPLN1) in the extracellular matrix enhances tumor cell plasticity and PDAC metastasis. Bioinformatic analysis showed that HAPLN1 expression is enriched in the basal PDAC subtype and associated with worse overall patient survival. In a mouse model for peritoneal carcinomatosis, HAPLN1-induced immunomodulation favors a more permissive microenvironment, which accelerates the peritoneal spread of tumor cells. Mechanistically, HAPLN1, via upregulation of tumor necrosis factor receptor 2 (TNFR2), promotes TNF-mediated upregulation of Hyaluronan (HA) production, facilitating EMT, stemness, invasion and immunomodulation. Extracellular HAPLN1 modifies cancer cells and fibroblasts, rendering them more immunomodulatory. As such, we identify HAPLN1 as a prognostic marker and as a driver for peritoneal metastasis in PDAC.
Asunto(s)
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Neoplasias Peritoneales , Ratones , Animales , Peritoneo/metabolismo , Neoplasias Peritoneales/patología , Ácido Hialurónico , Neoplasias Pancreáticas/genética , Carcinoma Ductal Pancreático/genética , Línea Celular Tumoral , Metástasis de la Neoplasia/patología , Regulación Neoplásica de la Expresión Génica , Microambiente Tumoral , Neoplasias PancreáticasRESUMEN
The BCL2 inhibitor venetoclax (VEN) in combination with azacitidine (5-AZA) is currently transforming acute myeloid leukemia (AML) therapy. However, there is a lack of clinically relevant biomarkers that predict response to 5-AZA/VEN. Here, we integrated transcriptomic, proteomic, functional, and clinical data to identify predictors of 5-AZA/VEN response. Although cultured monocytic AML cells displayed upfront resistance, monocytic differentiation was not clinically predictive in our patient cohort. We identified leukemic stem cells (LSC) as primary targets of 5-AZA/VEN whose elimination determined the therapy outcome. LSCs of 5-AZA/VEN-refractory patients displayed perturbed apoptotic dependencies. We developed and validated a flow cytometry-based "Mediators of apoptosis combinatorial score" (MAC-Score) linking the ratio of protein expression of BCL2, BCL-xL, and MCL1 in LSCs. MAC scoring predicts initial response with a positive predictive value of more than 97% associated with increased event-free survival. In summary, combinatorial levels of BCL2 family members in AML-LSCs are a key denominator of response, and MAC scoring reliably predicts patient response to 5-AZA/VEN. SIGNIFICANCE: Venetoclax/azacitidine treatment has become an alternative to standard chemotherapy for patients with AML. However, prediction of response to treatment is hampered by the lack of clinically useful biomarkers. Here, we present easy-to-implement MAC scoring in LSCs as a novel strategy to predict treatment response and facilitate clinical decision-making. This article is highlighted in the In This Issue feature, p. 1275.
Asunto(s)
Leucemia Mieloide Aguda , Proteómica , Humanos , Proteínas Proto-Oncogénicas c-bcl-2/genética , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/genética , Compuestos Bicíclicos Heterocíclicos con Puentes/farmacología , Compuestos Bicíclicos Heterocíclicos con Puentes/uso terapéutico , Azacitidina/farmacología , Azacitidina/uso terapéutico , Células Madre/metabolismo , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéuticoRESUMEN
Acute myeloid leukemia (AML) is a heterogeneous disease characterized by high rate of relapse and mortality. Current chemotherapies whilst successful in eradicating blasts, are less effective in eliminating relapse-causing leukemic stem cells (LSCs). Although LSCs are usually identified as CD34+CD38- cells, there is significant heterogeneity in surface marker expression, and CD34- LSCs exist particularly in NPM1mut AMLs. By analyzing diagnostic primary DNMT3AmutNPM1mut AML samples, we suggest a novel flow cytometry sorting strategy particularly useful for CD34neg AML subtypes. To enrich for LSCs independently of CD34 status, positive selection for GPR56 and negative selection for NKG2D ligands are used. We show that the functional reconstitution capacity of CD34- and CD34+ LSCs as well as their transcriptomes are very similar which support phenotypic plasticity. Furthermore, we show that although CD34+ subpopulations can contain next to LSCs also normal and/or preleukemic hematopoietic stem cells (HSCs), this is not the case in CD34-GPR56+NKG2DL- enriched LSCs which thus can be isolated with high purity. Finally, we show that patients with AML, who retain at the time of diagnosis a reserve of normal and/or preleukemic HSCs in their bone marrow able to reconstitute immunocompromised mice, have significantly longer relapse-free and overall survival than patients with AML in whom functional HSCs are no longer detectable.
Asunto(s)
Leucemia Mieloide Aguda , Células Madre Neoplásicas , Animales , Humanos , Ratones , Antígenos CD34 , Células Madre Hematopoyéticas , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/tratamiento farmacológico , Pronóstico , Receptores Acoplados a Proteínas GRESUMEN
The transcriptional coactivator YAP is emerging as a master regulator of cell growth. In the liver, YAP activity is linked to hepatomegaly, regeneration, dedifferentiation, and aggressive tumor growth. Here we present genomic studies to address how YAP may elicit such profound biological changes in murine models. YAP bound the genome in a TEAD-dependent manner, either at loci constitutively occupied by TEAD or by pioneering enhancers, which comprised a fraction of HNF4a/FOXA-bound embryonic enhancers active during embryonic development but silent in the adult. YAP triggered transcription on promoters by recruiting BRD4, enhancing H3K122 acetylation, and promoting RNApol2 loading and pause-release. YAP also repressed HNF4a target genes by binding to their promoters and enhancers, thus preventing RNApol2 pause-release. YAP activation led to the induction of hepatocyte proliferation, accompanied by tissue remodeling, characterized by polarized macrophages, exhausted T-lymphocytes and dedifferentiation of endothelial cells into proliferative progenitors. Overall, these analyses suggest that YAP is a master regulator of liver function that reshapes the enhancer landscape to control transcription of genes involved in metabolism, proliferation, and inflammation, subverts lineage specification programs by antagonizing HNF4a and modulating the immune infiltrate and the vascular architecture of the liver.
Asunto(s)
Hígado , Factores de Transcripción de Dominio TEA , Proteínas Señalizadoras YAP , Animales , Células Endoteliales/metabolismo , Elementos de Facilitación Genéticos , Factor Nuclear 4 del Hepatocito/metabolismo , Hígado/metabolismo , Macrófagos , Ratones , Proteínas Nucleares/metabolismo , Regiones Promotoras Genéticas , ARN Polimerasa II/metabolismo , Linfocitos T , Factores de Transcripción de Dominio TEA/metabolismo , Factores de Transcripción , Transcripción Genética , Proteínas Señalizadoras YAP/genética , Proteínas Señalizadoras YAP/metabolismoRESUMEN
Acute Myeloid Leukemia is one of the most aggressive blood cancers with a high frequency of relapse. While standard chemotherapy is able to target rapidly proliferating immature blasts, it fails to eradicate slowly proliferating Leukemic Stem Cells. Therefore, new therapeutic strategies that efficiently target LSCs are urgently needed. Recent studies suggest that LSCs have particular metabolic vulnerabilities, which would open the possibility of a therapeutic window with limited off-target effects on the normal hematopoietic system. In this issue of EMBO Molecular Medicine, So and colleagues investigate the mechanism of action of AG636, a new potent inhibitor of de novo pyrimidine synthesis, and discovered an unexpected link to AML protein translation essential for LSC function.
Asunto(s)
Leucemia Mieloide Aguda , Células Madre Neoplásicas , Humanos , Leucemia Mieloide Aguda/tratamiento farmacológico , Pirimidinas/farmacología , Pirimidinas/uso terapéuticoRESUMEN
Immature autoreactive B cells are present in all healthy individuals, but it is unclear which signals are required for their maturation into antibody-producing cells. Inducible depletion of γδ T cells show that direct interaction between γδ T cells and immature B cells in the spleen support an "innate" transition to mature B cells with a broad range of antigen specificities. IL-4 production of γδ T cells and cell-to-cell contact via CD30L support B cell maturation and induce genes of the unfolded protein response and mTORC1 signaling. Eight days after in vivo depletion of γδ T cells, increased numbers of B cells are already stuck in the transitional phase and express increased levels of IgD and CD21. Absence of γδ T cells leads also to reduced levels of serum anti-nuclear autoantibodies, making γδ T cells an attractive target to treat autoimmunity.
Asunto(s)
Células Precursoras de Linfocitos B , Receptores de Antígenos de Linfocitos T gamma-delta , Animales , Anticuerpos , Linfocitos B , Humanos , Ratones , Ratones Endogámicos C57BL , Células Precursoras de Linfocitos B/metabolismo , Receptores de Antígenos de Linfocitos T gamma-delta/metabolismo , Linfocitos TRESUMEN
Hematopoietic stem and progenitor cells (HSPCs) are responsible for the production of blood and immune cells. Throughout life, HSPCs acquire oncogenic aberrations that can cause hematological cancers. Although molecular programs maintaining stem cell integrity have been identified, safety mechanisms eliminating malignant HSPCs from the stem cell pool remain poorly characterized. Here, we show that HSPCs constitutively present antigens via major histocompatibility complex class II. The presentation of immunogenic antigens, as occurring during malignant transformation, triggers bidirectional interactions between HSPCs and antigen-specific CD4+ T cells, causing stem cell proliferation, differentiation, and specific exhaustion of aberrant HSPCs. This immunosurveillance mechanism effectively eliminates transformed HSPCs from the hematopoietic system, thereby preventing leukemia onset. Together, our data reveal a bidirectional interaction between HSPCs and CD4+ T cells, demonstrating that HSPCs are not only passive receivers of immunological signals but also actively engage in adaptive immune responses to safeguard the integrity of the stem cell pool.
Asunto(s)
Presentación de Antígeno , Células Madre Hematopoyéticas , Diferenciación Celular , Linfocitos TRESUMEN
Acute myeloid leukemia (AML) is an aggressive blood cancer with a poor prognosis. We report a comprehensive proteogenomic analysis of bone marrow biopsies from 252 uniformly treated AML patients to elucidate the molecular pathophysiology of AML in order to inform future diagnostic and therapeutic approaches. In addition to in-depth quantitative proteomics, our analysis includes cytogenetic profiling and DNA/RNA sequencing. We identify five proteomic AML subtypes, each reflecting specific biological features spanning genomic boundaries. Two of these proteomic subtypes correlate with patient outcome, but none is exclusively associated with specific genomic aberrations. Remarkably, one subtype (Mito-AML), which is captured only in the proteome, is characterized by high expression of mitochondrial proteins and confers poor outcome, with reduced remission rate and shorter overall survival on treatment with intensive induction chemotherapy. Functional analyses reveal that Mito-AML is metabolically wired toward stronger complex I-dependent respiration and is more responsive to treatment with the BCL2 inhibitor venetoclax.
Asunto(s)
Leucemia Mieloide Aguda , Proteogenómica , Humanos , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patología , ProteómicaRESUMEN
Pancreatic ductal adenocarcinoma (PDAC) is characterized by extensive desmoplasia, which challenges the molecular analyses of bulk tumor samples. Here we FACS-purified epithelial cells from human PDAC and normal pancreas and derived their genome-wide transcriptome and DNA methylome landscapes. Clustering based on DNA methylation revealed two distinct PDAC groups displaying different methylation patterns at regions encoding repeat elements. Methylationlow tumors are characterized by higher expression of endogenous retroviral transcripts and double-stranded RNA sensors, which lead to a cell-intrinsic activation of an interferon signature (IFNsign). This results in a protumorigenic microenvironment and poor patient outcome. Methylationlow/IFNsignhigh and Methylationhigh/IFNsignlow PDAC cells preserve lineage traits, respective of normal ductal or acinar pancreatic cells. Moreover, ductal-derived Kras G12D/Trp53 -/- mouse PDACs show higher expression of IFNsign compared with acinar-derived counterparts. Collectively, our data point to two different origins and etiologies of human PDACs, with the aggressive Methylationlow/IFNsignhigh subtype potentially targetable by agents blocking intrinsic IFN signaling. SIGNIFICANCE: The mutational landscapes of PDAC alone cannot explain the observed interpatient heterogeneity. We identified two PDAC subtypes characterized by differential DNA methylation, preserving traits from normal ductal/acinar cells associated with IFN signaling. Our work suggests that epigenetic traits and the cell of origin contribute to PDAC heterogeneity.This article is highlighted in the In This Issue feature, p. 521.
Asunto(s)
Carcinoma Ductal Pancreático/etiología , Carcinoma Ductal Pancreático/metabolismo , Metilación de ADN , Interferones/metabolismo , Neoplasias Pancreáticas/etiología , Neoplasias Pancreáticas/metabolismo , Secuencias Repetitivas de Ácidos Nucleicos , Carcinoma Ductal Pancreático/mortalidad , Carcinoma Ductal Pancreático/patología , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/metabolismo , Islas de CpG , Progresión de la Enfermedad , Susceptibilidad a Enfermedades , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Humanos , Modelos Biológicos , Neoplasias Pancreáticas/mortalidad , Neoplasias Pancreáticas/patología , Pronóstico , Reproducibilidad de los Resultados , Transducción de Señal , Transcriptoma , Microambiente Tumoral/genéticaRESUMEN
Duchenne muscular dystrophy (DMD) is one of the most common and severe forms of muscular dystrophy. Oxidative myofibre content, muscle vasculature architecture and exercise tolerance are impaired in DMD. Several studies have demonstrated that nutrient supplements ameliorate dystrophic features, thereby enhancing muscle performance. Here, we report that dietary supplementation with a specific branched-chain amino acid-enriched mixture (BCAAem) increased the abundance of oxidative muscle fibres associated with increased muscle endurance in dystrophic mdx mice. Amelioration of the fatigue index in BCAAem-treated mdx mice was caused by a cascade of events in the muscle tissue, which were promoted by endothelial nitric oxide synthase (eNOS) activation and vascular endothelial growth factor (VEGF) expression. VEGF induction led to recruitment of bone marrow (BM)-derived endothelial progenitors (EPs), which increased the capillary density of dystrophic skeletal muscle. Functionally, BCAAem mitigated the dystrophic phenotype of mdx mice without inducing dystrophin protein expression or replacing the dystrophin-associated glycoprotein (DAG) complex in the membrane, which is typically lost in DMD. BCAAem supplementation could be an effective adjuvant strategy in DMD treatment.
Asunto(s)
Aminoácidos/administración & dosificación , Suplementos Dietéticos , Distrofia Muscular de Duchenne/dietoterapia , Animales , Modelos Animales de Enfermedad , Células Progenitoras Endoteliales/efectos de los fármacos , Células Progenitoras Endoteliales/metabolismo , Femenino , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos mdx , Ratones Noqueados , Fibras Musculares Esqueléticas/efectos de los fármacos , Fibras Musculares Esqueléticas/metabolismo , Fibras Musculares Esqueléticas/patología , Fuerza Muscular/efectos de los fármacos , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/patología , Óxido Nítrico Sintasa de Tipo III/genética , Óxido Nítrico Sintasa de Tipo III/metabolismo , Estrés Oxidativo/efectos de los fármacos , Resistencia Física/efectos de los fármacos , Factor A de Crecimiento Endotelial Vascular/metabolismoAsunto(s)
Hematopoyesis/genética , Neoplasias/genética , Proteínas Nucleares/genética , Factores de Transcripción/genética , Aciltransferasas , Animales , Proteínas de Ciclo Celular , Diferenciación Celular/genética , Modelos Animales de Enfermedad , Trasplante de Células Madre Hematopoyéticas , Células Madre Hematopoyéticas/citología , Células Madre Hematopoyéticas/metabolismo , Células Madre Hematopoyéticas/patología , Xenoinjertos , Humanos , Ratones , Ratones Transgénicos , Neoplasias/sangre , Neoplasias/metabolismo , Neoplasias/patología , Proteínas Nucleares/metabolismo , Transducción de Señal , Factores de Transcripción/metabolismo , Resultado del TratamientoRESUMEN
Mammalian cells must integrate environmental cues to determine coherent physiological responses. The transcription factors Myc and YAP-TEAD act downstream from mitogenic signals, with the latter responding also to mechanical cues. Here, we show that these factors coordinately regulate genes required for cell proliferation. Activation of Myc led to extensive association with its genomic targets, most of which were prebound by TEAD. At these loci, recruitment of YAP was Myc-dependent and led to full transcriptional activation. This cooperation was critical for cell cycle entry, organ growth, and tumorigenesis. Thus, Myc and YAP-TEAD integrate mitogenic and mechanical cues at the transcriptional level to provide multifactorial control of cell proliferation.