Nucleophosmin (NPM1) is amongst the most frequently mutated genes in acute myeloid leukemia (AML). It is not known, however, how the resulting oncoprotein mutant-NPM1 is leukemogenic. To reveal the cellular machinery in which NPM1 participates in myeloid cells, we analyzed the endogenous NPM1 protein-interactome by mass-spectrometry, and discovered abundant amounts of the master transcription factor driver of monocyte lineage-differentiation PU.1 (SPI1). Mutant-NPM1, which aberrantly accumulates in cytoplasm, dislocated PU.1 into cytoplasm with it. CEBPA and RUNX1, the master transcription factors that collaborate with PU.1 to activate granulo-monocytic lineage-fates, remained nuclear, but without PU.1, their coregulator interactions were toggled from coactivators to corepressors, repressing instead of activating greater than 500 granulocyte and monocyte terminal-differentiation genes. An inhibitor of nuclear export, selinexor, by locking mutant-NPM1/PU.1 in the nucleus, activated terminal monocytic fates. Direct depletion of the corepressor DNA methyltransferase 1 (DNMT1) from the CEBPA/RUNX1 protein interactome using the clinical drug decitabine activated terminal granulocytic fates. Together, these non-cytotoxic treatments extended survival by greater than 160 days versus vehicle in a patient-derived xenotransplant model of NPM1/FLT3-mutated AML. In sum, mutant-NPM1 represses monocyte and granulocyte terminal-differentiation by disrupting PU.1/CEBPA/RUNX1 collaboration, a transforming action that can be reversed by pharmacodynamically-directed dosing of clinical small molecules.
Xiaorong Gu, Quteba Ebrahem, Reda Z. Mahfouz, Metis Hasipek, Francis Enane, Tomas Radivoyevitch, Nicolas Rapin, Bartlomiej Przychodzen, Zhenbo Hu, Ramesh Balusu, Claudiu V. Cotta, David Wald, Christian Argueta, Yosef Landesman, Maria Paola Martelli, Brunangelo Falini, Hetty Carraway, Bo T. Porse, Jaroslaw P. Maciejewski, Babal K. Jha, Yogen Saunthararajah
Germinal centers (GCs) are major sites of clonal B cell expansion and generation of long-lived, high-affinity antibody responses to pathogens. Signaling through toll-like receptors(TLRs) on B cells promotes many aspects of GC B cell responses, including affinity-maturation, class-switching and differentiation into long-lived memory and plasma cells. A major challenge for effective vaccination is identifying strategies to specifically promote GC B cell responses. Here we have identified a mechanism of regulation of GC B cell TLR signaling, mediated by αv integrins and non-canonical autophagy. Using B cell-specific αv-knockout mice, we show that loss of αv-mediated TLR regulation increased GC B cell expansion, somatic-hypermutation, class-switching, and generation of long-lived plasma cells after immunization with virus-like particles(VLPs) or antigens associated with TLR ligand adjuvants. Furthermore, targeting αv-mediated regulation increased the magnitude and breadth of antibody responses to influenza virus vaccination. These data therefore identify a mechanism of regulation of GC B cells, which can be targeted to enhance antibody responses to vaccination.
Fiona Raso, Sara Sagadiev, Samuel Du, Emily Gage, Tanvi Arkatkar, Genita Metzler, Lynda M. Stuart, Mark T. Orr, David Rawlings, Shaun Jackson, Adam Lacy-Hulbert, Mridu Acharya
Genome-wide association studies have repeatedly mapped susceptibility loci for emphysema to genes that modify hedgehog signaling, but the functional relevance of hedgehog signaling to this morbid disease remains unclear. In the current study, we identified a broad population of mesenchymal cells in the adult murine lung receptive to hedgehog signaling, characterized by higher activation of hedgehog surrounding the proximal airway relative to the distal alveoli. Single cell RNA-sequencing showed that the hedgehog-receptive mesenchyme is composed of mostly fibroblasts with distinct proximal and distal subsets with discrete identities. Ectopic hedgehog activation in the distal fibroblasts promoted expression of proximal fibroblast markers, and promoted loss of distal alveoli and airspace enlargement of over twenty percent compared to controls. We found that hedgehog suppressed mesenchymal-derived mitogens enriched in distal fibroblasts that regulate alveolar stem cell regeneration and airspace size. Finally, single cell analysis of the human lung mesenchyme showed that segregated proximal-distal identity with preferential hedgehog activation in the proximal fibroblasts is conserved between mice and humans. In conclusion, we showed that differential hedgehog activation segregates mesenchymal identities of distinct fibroblast subsets, and disruption of fibroblast identity can alter the alveolar stem cell niche leading to emphysematous changes in the murine lung.
Chaoqun Wang, Nabora S. Reyes de Mochel, Stephanie A. Christenson, Monica Cassandras, Rebecca Moon, Alexis N. Brumwell, Lauren E. Byrnes, Alfred Li, Yasuyuki Yokosaki, Peiying Shan, Julie B. Sneddon, David Jablons, Patty J. Lee, Michael A. Matthay, Harold A. Chapman, Tien Peng
Cyclin D1 is an oncogene frequently overexpressed in human cancers that plays a dual function as cell cycle and transcriptional regulator, although the latter is widely unexplored. Here, we investigated the transcriptional role of cyclin D1 in lymphoid tumor cells with cyclin D1 oncogenic overexpression. Cyclin D1 showed widespread binding to the promoters of most actively transcribed genes and the promoter occupancy positively correlated with the transcriptional output of targeted genes. Despite this association, the overexpression of cyclin D1 in lymphoid cells led to a global transcriptional downmodulation that was proportional to cyclin D1 levels. This cyclin D1 dependent global transcriptional downregulation was associated with a reduced nascent transcription and an accumulation of promoter-proximal paused RNA Polymerase II (Pol II) that colocalized with cyclin D1. Concordantly, cyclin D1 overexpresion promoted an increment of the Poll II pausing index. This transcriptional impairment seems to be mediated by the interaction of cyclin D1 with the transcription machinery. In addition, cyclin D1 overexpression sensitized cells to transcription inhibitors revealing a synthetic lethality interaction that it was also observed in primary MCL cases. This global transcriptional dysregulation expands the oncogenic cyclin D1 functions and places the transcriptional machinery as a potential therapeutic target in cyclin D1 overexpressing tumors.
Robert Albero, Anna Enjuanes, Santiago Demajo, Giancarlo Castellano, Magda Pinyol, Noelia García, Cristina Capdevila, Guillem Clot, Helena Suárez-Cisneros, Mariko Shimada, Kennosuke Karube, Mónica López-Guerra, Dolors Colomer, Sílvia Beà, José Ignacio Martin-Subero, Elías Campo, Pedro Jares
Induction of TLR2 activation depends on its association with adapter protein MyD88. We have found that levels of TLR2 and MyD88 are elevated in the hippocampus and cortex of Alzheimer’s disease (AD) patients and 5XFAD mouse model of AD. Since there is no specific inhibitor of TLR2, to target induced TLR2 from therapeutic angle, we engineered a peptide corresponding to the TLR2-interacting domain of MyD88 (TIDM) that binds to the BB loop of only TLR2, but not other TLRs. Interestingly, wild type (wt) TIDM peptide inhibited microglial activation induced by fibrillar Aβ1-42 and lipoteichoic acid, but not 1-methyl-4-phenylpyridinium, double-stranded RNA, bacterial lipopolysaccharide, flagellin, and CpG DNA. After intranasal administration, wtTIDM peptide reached the hippocampus, reduced hippocampal glial activation, lowered Aβ burden, attenuated neuronal apoptosis, and improved memory and learning in 5XFAD mice. However, wtTIDM peptide was not effective in 5XFAD mice lacking TLR2. In addition to 5XFAD mice, wtTIDM peptide also suppressed the disease process in mice with experimental allergic encephalomyelitis and collagen-induced arthritis. Therefore, selective targeting of activated status of one component of the innate immune system by wtTIDM peptide may be beneficial in AD as well as other disorders in which TLR2-MyD88 signaling plays a role in disease pathogenesis.
Suresh B. Rangasamy, Malabendu Jana, Avik Roy, Grant T. Corbett, Madhuchhanda Kundu, Sujyoti Chandra, Susanta Mondal, Sridevi Dasarathi, Elliott J. Mufson, Rama K. Mishra, Chi-Hao Luan, David A. Bennett, Kalipada Pahan
Anaplastic thyroid carcinomas (ATC) have a high prevalence of BRAF and TP53 mutations. A trial of vemurafenib in non-melanoma BRAFV600E-mutant cancers showed significant, although short-lived, responses in ATCs, indicating that these virulent tumors remain addicted to BRAF despite their high mutation burden. To explore the mechanisms mediating acquired resistance to BRAF blockade we generated mice with thyroid-specific deletion of p53 and dox-dependent expression of BRAFV600E, 50% of which developed ATCs after dox treatment. Upon dox withdrawal there was complete regression in all mice, although recurrences were later detected in 85% of animals. The relapsed tumors had elevated MAPK transcriptional output, and retained responses to the MEK/RAF inhibitor CH5126766 in vivo and in vitro. Whole exome sequencing identified recurrent focal amplifications of chromosome 6, with a minimal region of overlap that included Met. Met-amplified recurrences overexpressed the receptor as well as its ligand Hgf. Growth, signaling and viability of Met-amplified tumor cells were suppressed in vitro and in vivo by the Met kinase inhibitors PF-04217903 and crizotinib, whereas primary ATCs and Met-diploid relapses were resistant. Hence, recurrences are the rule after BRAF suppression in murine ATCs, most commonly due to activation of HGF/MET signaling, which generates exquisite dependency to MET kinase inhibitors.
Jeffrey A. Knauf, Kathleen A. Luckett, Kuen-Yuan Chen, Francesca Voza, Nicholas D. Socci, Ronald Ghossein, James A. Fagin
Bi-allelic loss-of-function mutations of the NCF4 gene, encoding the p40phox subunit of the phagocyte NADPH oxidase, have been described in only one patient. We report 24 p40phox-deficient patients from 12 additional families in eight countries. These patients display eight different in-frame or out-of-frame mutations of NCF4, homozygous in 11 families and compound heterozygous in another. When overexpressed in NB4 neutrophil-like cells and EBV-transformed B cells in vitro, the mutant alleles were found to be loss-of-function, with the exception of the p.R58C and c.120_134del alleles, which were hypomorphic. Particle-induced NADPH oxidase activity was subnormal in the patients’ neutrophils, whereas PMA-induced DHR oxidation, which is widely used as a diagnostic test for CGD, was normal in some of the patients. Moreover, the NADPH oxidase activity of EBV-transformed B cells was also subnormal, whereas that of mononuclear phagocytes was normal. Finally, the killing of Candida albicans and Aspergillus fumigatus hyphae by neutrophils was conserved in these patients. The patients described here suffer from hyperinflammation and peripheral infections, but they do not display any of the invasive bacterial and fungal infections seen in CGD. In conclusion, inherited p40phox deficiency underlies a distinctive condition, resembling a mild, atypical form of CGD
Annemarie van de Geer, Alejandro Nieto-Patlán, Douglas B. Kuhns, Anton T.J. Tool, Andrés A. Arias, Matthieu Bouaziz, Martin de Boer, José Luis Franco, Roel P. Gazendam, John L. van Hamme, Michel van Houdt, Karin van Leeuwen, Paul J.H. Verkuijlen, Timo K. van den Berg, Juan F. Alzate, Carlos A. Arango-Franco, Vritika Batura, Andrea R. Bernasconi, Barbara Boardman, Claire Booth, Siobhan O. Burns, Felipe Cabarcas, Nadine Cerf Bensussan, Fabienne Charbit-Henrion, Anniek Corveleyn, Caroline Deswarte, María Esnaola Azcoiti, Dirk Foell, John I. Gallin, Carlos Garcés, Margarida Guedes, Claas H. Hinze, Steven M. Holland, Stephen M. Hughes, Patricio Ibañez, Harry L. Malech, Isabelle Meyts, Marcela Moncada-Velez, Kunihiko Moriya, Esmeralda Neves, Matias Oleastro, Laura Perez, Vimel Rattina, Carmen Oleaga-Quintas, Neil Warner, Aleixo M. Muise, Jeanet Serafin López, Eunice Trindade, Julia Vasconselos, Severine Vermeire, Helmut Wittkowski, Austen Worth, Laurent Abel, Mary C. Dinauer, Peter D. Arkwright, Dirk Roos, Jean-Laurent Casanova, Taco W. Kuijpers, Jacinta Bustamante
Red blood cells (RBCs) influence rheology, release ADP, ATP and nitric oxide suggesting a role for RBCs in hemostasis and thrombosis. Here we provide evidence for a significant contribution of RBCs to thrombus formation. Anemic mice showed enhanced occlusion times upon injury of the carotid artery. A small population of RBCs was located to platelet thrombi and enhanced platelet activation by a direct cell contact via the FasL-FasR (CD95) pathway known to induce apoptosis. Activation of platelets in the presence of RBCs led to platelet FasL exposure that activated FasR on RBCs responsible for externalization of phosphatidylserine (PS) on the RBC membrane. Inhibition or genetic deletion of either FasL or FasR resulted in reduced PS exposure of RBCs and platelets, decreased thrombin generation and reduced thrombus formation in vitro and protection against arterial thrombosis in vivo. Direct cell contacts of platelets and RBCs via FasL-FasR were shown after ligation of the inferior vena cava (IVC) and in surgical specimens of patients after thrombectomy. In a flow restriction model of the IVC, reduced thrombus formation was observed in FasL–/– mice. Taken together, our data reveal a significant contribution of RBCs to thrombosis by the FasL-FasR pathway.
Christoph Klatt, Irena Krüger, Saskia Zey, Kim-Jürgen Krott, Martina Spelleken, Nina Sarah Gowert, Alexander Oberhuber, Lena Pfaff, Wiebke Lückstädt, Kerstin Jurk, Martin Schaller, Hadi Al-Hasani, Jürgen Schrader, Steffen Massberg, Konstantin Stark, Hubert Schelzig, Malte Kelm, Margitta Elvers
DNA damaging chemotherapy and radiation therapy are integrated into the treatment paradigm of the majority of cancer patients. Recently, immunotherapy that targets the immunosuppressive interaction between Programmed Death 1 (PD-1) and its ligand PD-L1 has been approved for malignancies including non-small lung cancer (NSCLC), melanoma, and head and neck squamous cell carcinoma (HNSCC). ATR is a DNA damage signaling kinase activated at damaged replication forks and ATR kinase inhibitors potentiate the cytotoxicity of DNA damaging chemotherapies. We show here that the ATR kinase inhibitor AZD6738 combines with conformal radiation therapy to attenuate radiation-induced CD8+ T cell exhaustion and potentiate CD8+ T cell activity in mouse models of Kras-mutant cancer. Mechanistically, AZD6738 blocks radiation-induced PD-L1 upregulation on tumor cells and dramatically decreases the number of tumor-infiltrating T regulatory (Treg) cells. Remarkably, AZD6738 combines with conformal radiation therapy to generate immunologic memory in complete responder mice. Our work raises the exciting possibility that a single pharmacologic agent may enhance the cytotoxic effects of radiation while concurrently potentiating radiation-induced antitumor immune responses.
Frank P. Vendetti, Pooja Karukonda, David A. Clump, Troy Teo, Ronald Lalonde, Katriana Nugent, Matthew Ballew, Brian F. Kiesel, Jan H. Beumer, Saumendra N. Sarkar, Thomas P. Conrads, Mark J. O'Connor, Robert L. Ferris, Phuoc T. Tran, Greg M. Delgoffe, Christopher J. Bakkenist
Cancer cell dependence on activated oncogenes is targeted therapeutically, but acquired resistance is virtually unavoidable. Here we show that the treatment of addicted melanoma cells with BRAF-inhibitors, and of breast cancer cells with HER2-targeted drugs, led to an adaptive rise in Neuropilin-1 (NRP1) expression, which is crucial for the onset of acquired resistance to therapy. Moreover, NRP1 levels dictated the efficacy of MET oncogene-inhibitors in addicted stomach and lung carcinoma cells. Mechanistically, NRP1 induced a JNK-dependent signaling cascade leading to the upregulation of alternative effector kinases, EGFR or IGF1R, which in turn sustained cancer cell growth and mediated acquired resistance to BRAF, HER2, or MET inhibitors. Notably, the combination with NRP1-interfering molecules improved the efficacy of oncogene-targeted drugs, and prevented, or even reversed, the onset of resistance in cancer cells and tumor models. Our study provides the rationale for targeting the NRP1-dependent upregulation of tyrosine kinases, responsible for loss of responsiveness to oncogene-targeted therapies.
Sabrina Rizzolio, Gabriella Cagnoni, Chiara Battistini, Stefano Bonelli, Claudio Isella, Jo A. Van Ginderachter, René Bernards, Federica Di Nicolantonio, Silvia Giordano, Luca Tamagnone
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