ABSTRACT
The killifish Nothobranchius furzeri is the shortest-lived vertebrate that can be bred in the laboratory. Its rapid growth, early sexual maturation, fast aging, and arrested embryonic development (diapause) make it an attractive model organism in biomedical research. Here, we report a draft sequence of its genome that allowed us to uncover an intra-species Y chromosome polymorphism representing-in real time-different stages of sex chromosome formation that display features of early mammalian XY evolution "in action." Our data suggest that gdf6Y, encoding a TGF-ß family growth factor, is the master sex-determining gene in N. furzeri. Moreover, we observed genomic clustering of aging-related genes, identified genes under positive selection, and revealed significant similarities of gene expression profiles between diapause and aging, particularly for genes controlling cell cycle and translation. The annotated genome sequence is provided as an online resource (http://www.nothobranchius.info/NFINgb).
Subject(s)
Biological Evolution , Killifishes/genetics , Sex Chromosomes , Aging , Animals , Female , Genome , Killifishes/physiology , Male , Molecular Sequence Data , Sex Determination ProcessesABSTRACT
An Amendment to this paper has been published and can be accessed via a link at the top of the paper.
ABSTRACT
BACKGROUND: The immune peptidome of OPSCC has not previously been studied. Cancer-antigen specific vaccination may improve clinical outcome and efficacy of immune checkpoint inhibitors such as PD1/PD-L1 antibodies. METHODS: Mapping of the OPSCC HLA ligandome was performed by mass spectrometry (MS) based analysis of naturally presented HLA ligands isolated from tumour tissue samples (n = 40) using immunoaffinity purification. The cohort included 22 HPV-positive (primarily HPV-16) and 18 HPV-negative samples. A benign reference dataset comprised of the HLA ligandomes of benign haematological and tissue datasets was used to identify tumour-associated antigens. RESULTS: MS analysis led to the identification of naturally HLA-presented peptides in OPSCC tumour tissue. In total, 22,769 peptides from 9485 source proteins were detected on HLA class I. For HLA class II, 15,203 peptides from 4634 source proteins were discovered. By comparative profiling against the benign HLA ligandomic datasets, 29 OPSCC-associated HLA class I ligands covering 11 different HLA allotypes and nine HLA class II ligands were selected to create a peptide warehouse. CONCLUSION: Tumour-associated peptides are HLA-presented on the cell surfaces of OPSCCs. The established warehouse of OPSCC-associated peptides can be used for downstream immunogenicity testing and peptide-based immunotherapy in (semi)personalised strategies.
Subject(s)
HLA Antigens , Otorhinolaryngologic Neoplasms , Papillomavirus Infections , Squamous Cell Carcinoma of Head and Neck , Humans , Papillomavirus Infections/immunology , Peptides/immunology , Vaccination , Otorhinolaryngologic Neoplasms/immunology , HLA Antigens/immunology , Antigens, Neoplasm/immunology , Human papillomavirus 16 , Human papillomavirus 18ABSTRACT
MOTIVATION: Cancer is a complex and heterogeneous disease involving multiple somatic mutations that accumulate during its progression. In the past years, the wide availability of genomic data from patients' samples opened new perspectives in the analysis of gene mutations and alterations. Hence, visualizing and further identifying genes mutated in massive sets of patients are nowadays a critical task that sheds light on more personalized intervention approaches. RESULTS: Here, we extensively review existing tools for visualization and analysis of alteration data. We compare different approaches to study mutual exclusivity and sample coverage in large-scale omics data. We complement our review with the standalone software AVAtar ('analysis and visualization of alteration data') that integrates diverse aspects known from different tools into a comprehensive platform. AVAtar supplements customizable alteration plots by a multi-objective evolutionary algorithm for subset identification and provides an innovative and user-friendly interface for the evaluation of concurrent solutions. A use case from personalized medicine demonstrates its unique features showing an application on vaccination target selection. AVAILABILITY: AVAtar is available at: https://github.com/sysbio-bioinf/avatar. CONTACT: hans.kestler@uni-ulm.de, phone: +49 (0) 731 500 24 500, fax: +49 (0) 731 500 24 502.
Subject(s)
Computational Biology/methods , Gene Expression Profiling/methods , Gene Expression Regulation, Neoplastic , Genome, Human/genetics , Genomics/methods , Neoplasms/genetics , Algorithms , Humans , Mutation , Precision Medicine/methodsABSTRACT
The functionality of stem cells declines during ageing, and this decline contributes to ageing-associated impairments in tissue regeneration and function. Alterations in developmental pathways have been associated with declines in stem-cell function during ageing, but the nature of this process remains poorly understood. Hox genes are key regulators of stem cells and tissue patterning during embryogenesis with an unknown role in ageing. Here we show that the epigenetic stress response in muscle stem cells (also known as satellite cells) differs between aged and young mice. The alteration includes aberrant global and site-specific induction of active chromatin marks in activated satellite cells from aged mice, resulting in the specific induction of Hoxa9 but not other Hox genes. Hoxa9 in turn activates several developmental pathways and represents a decisive factor that separates satellite cell gene expression in aged mice from that in young mice. The activated pathways include most of the currently known inhibitors of satellite cell function in ageing muscle, including Wnt, TGFß, JAK/STAT and senescence signalling. Inhibition of aberrant chromatin activation or deletion of Hoxa9 improves satellite cell function and muscle regeneration in aged mice, whereas overexpression of Hoxa9 mimics ageing-associated defects in satellite cells from young mice, which can be rescued by the inhibition of Hoxa9-targeted developmental pathways. Together, these data delineate an altered epigenetic stress response in activated satellite cells from aged mice, which limits satellite cell function and muscle regeneration by Hoxa9-dependent activation of developmental pathways.
Subject(s)
Cellular Senescence , Epistasis, Genetic , Growth and Development/genetics , Homeodomain Proteins/metabolism , Satellite Cells, Skeletal Muscle/cytology , Satellite Cells, Skeletal Muscle/metabolism , Stress, Physiological/genetics , Aging , Animals , Cellular Senescence/genetics , Chromatin/genetics , Chromatin/metabolism , Female , Homeodomain Proteins/biosynthesis , Homeodomain Proteins/genetics , Male , Mice , Muscle, Skeletal/cytology , Muscle, Skeletal/metabolism , Regeneration/geneticsABSTRACT
OBJECTIVE: ATM serine/threonine kinase (ATM) is the most frequently mutated DNA damage response gene, involved in homologous recombination (HR), in pancreatic ductal adenocarcinoma (PDAC). DESIGN: Combinational synergy screening was performed to endeavour a genotype-tailored targeted therapy. RESULTS: Synergy was found on inhibition of PARP, ATR and DNA-PKcs (PAD) leading to synthetic lethality in ATM-deficient murine and human PDAC. Mechanistically, PAD-induced PARP trapping, replication fork stalling and mitosis defects leading to P53-mediated apoptosis. Most importantly, chemical inhibition of ATM sensitises human PDAC cells toward PAD with long-term tumour control in vivo. Finally, we anticipated and elucidated PARP inhibitor resistance within the ATM-null background via whole exome sequencing. Arising cells were aneuploid, underwent epithelial-mesenchymal-transition and acquired multidrug resistance (MDR) due to upregulation of drug transporters and a bypass within the DNA repair machinery. These functional observations were mirrored in copy number variations affecting a region on chromosome 5 comprising several of the upregulated MDR genes. Using these findings, we ultimately propose alternative strategies to overcome the resistance. CONCLUSION: Analysis of the molecular susceptibilities triggered by ATM deficiency in PDAC allow elaboration of an efficient mutation-specific combinational therapeutic approach that can be also implemented in a genotype-independent manner by ATM inhibition.
Subject(s)
Adenocarcinoma/genetics , Ataxia Telangiectasia Mutated Proteins/genetics , Carcinoma, Pancreatic Ductal/genetics , Homologous Recombination , Pancreatic Neoplasms/genetics , Poly(ADP-ribose) Polymerase Inhibitors/pharmacology , Adenocarcinoma/drug therapy , Animals , Apoptosis , Carcinoma, Pancreatic Ductal/drug therapy , Cell Line, Tumor , Cell Survival , DNA Copy Number Variations , DNA Damage , DNA Repair , Drug Resistance, Multiple/genetics , Drug Synergism , Epithelial-Mesenchymal Transition , Genotype , Humans , Mice , Pancreatic Neoplasms/drug therapy , PrognosisABSTRACT
Programmed-death-1 (PD1) antibodies are approved for recurrent and metastatic head and neck squamous cell carcinoma. Multiple drugs targeting costimulatory and coinhibitory immune checkpoint molecules (ICM) have been discovered. However, it remains unknown how these ICM are affected by curative conventional therapy on different immune cell subsets during the course of treatment. In the prospective noninterventional clinical study titled "Immune Response Evaluation to Curative conventional Therapy" (NCT03053661), 22 patients were prospectively enrolled. Blood samples were drawn at defined time points throughout curative conventional treatment and follow-up. Immune cells (IC) from the different time points were assessed by multicolor flow cytometry. The following ICM were measured by flow cytometry: PD1, CTLA4, BTLA, CD137, CD27, GITR, OX40, LAG3 and TIM3. Dynamics of ICM expression were assessed using nonparametric paired samples tests. Significant changes were noted for PD1, BTLA and CD27 on multiple IC types during or after radiotherapy. Nonsignificant trends for increased expression of OX40 and GITR from baseline until the end of RT were observed on CD4 T cells and CD4+ CD39+ T cells. In patients with samples at recurrence of disease, a nonsignificant increase of TIM3 and LAG3 positive CD4+ CD39+ T cells was evident, accompanied by an increase of double positive cells for TIM3/LAG3. Potential future targets to be combined with RT in the conventional treatment and anti-PD1/PD-L could be BTLA agonists, or agonistic antibodies to costimulatory ICM like CD137, OX40 or GITR. The combination of cetuximab with CD27 agonistic antibodies enhancing ADCC or the targeting of TIM3/LAG3 may be another promising strategy.
Subject(s)
Carcinoma, Squamous Cell/therapy , Head and Neck Neoplasms/therapy , Immune Checkpoint Proteins/metabolism , Immunotherapy/methods , Lymphocytes, Tumor-Infiltrating/metabolism , T-Lymphocyte Subsets/metabolism , Aged , CTLA-4 Antigen/metabolism , Carcinoma, Squamous Cell/immunology , Carcinoma, Squamous Cell/metabolism , Female , Follow-Up Studies , Head and Neck Neoplasms/immunology , Head and Neck Neoplasms/metabolism , Humans , Longitudinal Studies , Male , Middle Aged , Programmed Cell Death 1 Receptor/metabolism , Prospective StudiesABSTRACT
BACKGROUND & AIMS: Pancreatic tumor cells release small extracellular vesicles (sEVs, exosomes) that contain lipids and proteins, RNA, and DNA molecules that might promote formation of metastases. It is not clear what cargo these vesicles contain and how they are released. Protein kinase D1 (PRKD1) inhibits cell motility and is believed to be dysregulated in pancreatic ductal adenocarcinomas. We investigated whether it regulates production of sEVs in pancreatic cancer cells and their ability to form premetastatic niches for pancreatic cancer cells in mice. METHODS: We analyzed data from UALCAN and human pancreatic tissue microarrays to compare levels of PRKD1 between tumor and nontumor tissues. We studied mice with pancreas-specific disruption of Prkd1 (PRKD1KO mice), mice that express oncogenic KRAS (KC mice), and KC mice with disruption of Prkd1 (PRKD1KO-KC mice). Subcutaneous xenograft tumors were grown in NSG mice from Panc1 cells; some mice were then given injections of sEVs. Pancreata and lung tissues from mice were analyzed by histology, immunohistochemistry, and/or quantitative polymerase chain reaction; we performed nanoparticle tracking analysis of plasma sEVs. The Prkd1 gene was disrupted in Panc1 cells using CRISPR-Cas9 or knocked down with small hairpin RNAs, or PRKD1 activity was inhibited with the selective inhibitor CRT0066101. Pancreatic cancer cell lines were analyzed by gene-expression microarray, quantitative polymerase chain reaction, immunoblot, and immunofluorescence analyses. sEVs secreted by Panc1 cell lines were analyzed by flow cytometry, transmission electron microscopy, and mass spectrometry. RESULTS: Levels of PRKD1 were reduced in human pancreatic ductal adenocarcinoma tissues compared with nontumor tissues. PRKD1KO-KC mice developed more pancreatic intraepithelial neoplasia, at a faster rate, than KC mice, and had more lung metastases and significantly shorter average survival time. Serum from PRKD1KO-KC mice had increased levels of sEVs compared with KC mice. Pancreatic cancer cells with loss or inhibition of PRKD1 increased secretion of sEVs; loss of PRKD1 reduced phosphorylation of its substrate, cortactin, resulting in increased F-actin levels at the plasma membrane. sEVs from cells with loss or reduced expression of PRKD1 had altered content, and injection of these sEVs into mice increased metastasis of xenograft tumors to lung, compared with sEVs from pancreatic cells that expressed PRKD1. PRKD1-deficient pancreatic cancer cells showed increased loading of integrin α6ß4 into sEVs-a process that required CD82. CONCLUSIONS: Human pancreatic ductal adenocarcinoma has reduced levels of PRKD1 compared with nontumor pancreatic tissues. Loss of PRKD1 results in reduced phosphorylation of cortactin in pancreatic cancer cell lines, resulting in increased in F-actin at the plasma membrane and increased release of sEVs, with altered content. These sEVs promote metastasis of xenograft and pancreatic tumors to lung in mice.
Subject(s)
Carcinoma, Pancreatic Ductal/secondary , Extracellular Vesicles/metabolism , Lung Neoplasms/secondary , Pancreatic Neoplasms/pathology , Protein Kinase C/deficiency , Animals , Carcinogenesis/pathology , Carcinoma, Pancreatic Ductal/blood , Cell Line, Tumor , Cell Movement , Datasets as Topic , Down-Regulation , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Humans , Lung/pathology , Lung Neoplasms/blood , Mice , Mice, Knockout , Neoplasm Invasiveness/pathology , Oligonucleotide Array Sequence Analysis , Pancreas/pathology , Pancreatic Neoplasms/blood , Phosphorylation , Primary Cell Culture , Protein Kinase C/genetics , Xenograft Model Antitumor AssaysABSTRACT
The genetics of lifespan determination is poorly understood. Most research has been done on short-lived animals and it is unclear if these insights can be transferred to long-lived mammals like humans. Some African mole-rats (Bathyergidae) have life expectancies that are multiple times higher than similar sized and phylogenetically closely related rodents. To gain new insights into genetic mechanisms determining mammalian lifespans, we obtained genomic and transcriptomic data from 17 rodent species and scanned eleven evolutionary branches associated with the evolution of enhanced longevity for positively selected genes (PSGs). Indicating relevance for aging, the set of 250 identified PSGs showed in liver of long-lived naked mole-rats and short-lived rats an expression pattern that fits the antagonistic pleiotropy theory of aging. Moreover, we found the PSGs to be enriched for genes known to be related to aging. Among these enrichments were "cellular respiration" and "metal ion homeostasis", as well as functional terms associated with processes regulated by the mTOR pathway: translation, autophagy and inflammation. Remarkably, among PSGs are RHEB, a regulator of mTOR, and IGF1, both central components of aging-relevant pathways, as well as genes yet unknown to be aging-associated but representing convincing functional candidates, e.g. RHEBL1, AMHR2, PSMG1 and AGER. Exemplary protein homology modeling suggests functional consequences for amino acid changes under positive selection. Therefore, we conclude that our results provide a meaningful resource for follow-up studies to mechanistically link identified genes and amino acids under positive selection to aging and lifespan determination.
Subject(s)
Longevity/genetics , Rodentia/genetics , Selection, Genetic , Animals , Genome , Homeostasis , Ion Transport , Oxidative Stress , Species Specificity , TranscriptomeABSTRACT
BACKGROUND: Overcoming the COVID-19 crisis requires new ideas and strategies for online communication of personal medical information and patient empowerment. Rapid testing of a large number of subjects is essential for monitoring and delaying the spread of SARS-CoV-2 in order to mitigate the pandemic's consequences. People who do not know that they are infected may not stay in quarantine and, thus, risk infecting others. Unfortunately, the massive number of COVID-19 tests performed is challenging for both laboratories and the units that conduct throat swabs and communicate the results. OBJECTIVE: The goal of this study was to reduce the communication burden for health care professionals. We developed a secure and easy-to-use tracking system to report COVID-19 test results online that is simple to understand for the tested subjects as soon as these results become available. Instead of personal calls, the system updates the status and the results of the tests automatically. This aims to reduce the delay when informing testees about their results and, consequently, to slow down the virus spread. METHODS: The application in this study draws on an existing tracking tool. With this open-source and browser-based online tracking system, we aim to minimize the time required to inform the tested person and the testing units (eg, hospitals or the public health care system). The system can be integrated into the clinical workflow with very modest effort and avoids excessive load to telephone hotlines. RESULTS: The test statuses and results are published on a secured webpage, enabling regular status checks by patients; status checks are performed without the use of smartphones, which has some importance, as smartphone usage diminishes with age. Stress tests and statistics show the performance of our software. CTest is currently running at two university hospitals in Germany-University Hospital Ulm and University Hospital Tübingen-with thousands of tests being performed each week. Results show a mean number of 10 (SD 2.8) views per testee. CONCLUSIONS: CTest runs independently of existing infrastructures, aims at straightforward integration, and aims for the safe transmission of information. The system is easy to use for testees. QR (Quick Response) code links allow for quick access to the test results. The mean number of views per entry indicates a reduced amount of time for both health care professionals and testees. The system is quite generic and can be extended and adapted to other communication tasks.
Subject(s)
COVID-19/diagnosis , COVID-19/psychology , Communication , Medical Informatics/organization & administration , Medical Informatics/standards , Pandemics , Patient Participation , SARS-CoV-2/isolation & purification , COVID-19/epidemiology , COVID-19/virology , Germany , Humans , Time FactorsABSTRACT
[This corrects the article DOI: 10.2196/27348.].
ABSTRACT
Second mitochondria-derived activator of caspase (SMAC) mimetics (SMs) targeting inhibitor of apoptosis proteins (IAPs) activate cell death pathways, and are currently being evaluated in clinical trials. Their successful therapeutic implementation requires upfront identification of patients who could benefit from a SM-based treatment but biomarkers for SM sensitivity have not yet been described. Here, we analyzed the intrinsic activity of two monovalent (AT406 and LCL161) and two bivalent (Birinapant and BV6) SMs on unselected patient-derived pediatric precursor B-cell acute lymphoblastic leukemia (BCP-ALL) identifying a subset of patient samples to be particularly sensitive to SM-induced cell death. This subset was defined by a characteristic gene expression signature with 127 differentially regulated genes, amongst them TNFRSF1A encoding TNFR1, and a critical role of TNFR1 in SM-induced cell death in sensitive BCP-ALL was confirmed on the functional level. Interestingly, samples with intermediate or low sensitivity to SMs were sensitized to SM-induced cell death by inhibition of caspases using zVAD.fmk or Emricasan, a pan-caspase inhibitor in clinical trials. When we compared our expression data to published data sets, we identified an overlap of four genes to be commonly differentially regulated in SM-sensitive BCP-ALL, that is, TSPAN7, DIPK1C, MTX2 and, again, TNFRSF1A. Functional testing revealed that this set of genes identified samples with high sensitivity to SM treatment. In summary, our data suggest using this gene signature as biomarker predicting response to SM treatment and point to the development of new combinatorial treatments consisting of SMs and pan-caspase inhibitors for a successful clinical implementation of SMs in treatment of BCP-ALL.
Subject(s)
Apoptosis Regulatory Proteins/antagonists & inhibitors , Azocines/pharmacology , Benzhydryl Compounds/pharmacology , Dipeptides/pharmacology , Indoles/pharmacology , Inhibitor of Apoptosis Proteins/antagonists & inhibitors , Mitochondrial Proteins/antagonists & inhibitors , Oligopeptides/pharmacology , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Thiazoles/pharmacology , Animals , Apoptosis/drug effects , Caspase Inhibitors/pharmacology , Cell Line, Tumor , Female , Humans , Mice , Mice, Inbred NOD , Mice, SCID , Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics , Precursor Cells, B-Lymphoid/metabolism , Receptors, Tumor Necrosis Factor, Type I/genetics , Receptors, Tumor Necrosis Factor, Type I/metabolism , Xenograft Model Antitumor AssaysABSTRACT
There have been hints that nonviral cancer antigens are differentially expressed in human papillomavirus (HPV)-positive and HPV-negative head and neck squamous cell carcinoma (HNSCC). Antibody responses (AR) to cancer antigens may be used to indirectly determine cancer antigen expression in the tumor using a noninvasive and tissue-saving liquid biopsy. Here, we set out to characterize AR to a panel of nonviral cancer antigens in HPV-positive and HPV-negative HNSCC patients. A fluorescent microbead multiplex serology to 29 cancer antigens (16 cancer-testis antigens, 5 cancer-retina antigens and 8 oncogenes) and 29 HPV-antigens was performed in 382 HNSCC patients from five independent cohorts (153 HPV-positive and 209 HPV-negative). AR to any of the cancer antigens were found in 272/382 patients (72%). The ten most frequent AR were CT47, cTAGE5a, c-myc, LAGE-1, MAGE-A1, -A3, -A4, NY-ESO-1, SpanX-a1 and p53. AR to MAGE-A3, MAGE-A9 and p53 were found at significantly different prevalences by HPV status. An analysis of AR mean fluorescent intensity values uncovered remarkably different AR clusters by HPV status. To identify optimal antigen selections covering a maximum of patients with ≤10 AR, multiobjective optimization revealed distinct antigen selections by HPV status. We identified that AR to nonviral antigens differ by HPV status indicating differential antigen expression. Multiplex serology may be used to characterize antigen expression using serum or plasma as a tissue-sparing liquid biopsy. Cancer antigen panels should address the distinct antigen repertoire of HPV-positive and HPV-negative HNSCC.
Subject(s)
Antibody Formation/immunology , Antigens, Neoplasm/immunology , Head and Neck Neoplasms/immunology , Head and Neck Neoplasms/virology , Papillomaviridae/immunology , Squamous Cell Carcinoma of Head and Neck/immunology , Squamous Cell Carcinoma of Head and Neck/virology , Adolescent , Adult , Aged , Aged, 80 and over , Biomarkers, Tumor/immunology , Cohort Studies , Female , Humans , Male , Membrane Proteins/immunology , Middle Aged , Neoplasm Proteins/immunology , Papillomavirus Infections/immunology , Papillomavirus Infections/virology , Young AdultABSTRACT
Aging and carcinogenesis coincide with the accumulation of DNA damage and mutations in stem and progenitor cells. Molecular mechanisms that influence responses of stem and progenitor cells to DNA damage remain to be delineated. Here, we show that niche positioning and Wnt signaling activity modulate the sensitivity of intestinal stem and progenitor cells (ISPCs) to DNA damage. ISPCs at the crypt bottom with high Wnt/ß-catenin activity are more sensitive to DNA damage compared to ISPCs in position 4 with low Wnt activity. These differences are not induced by differences in cell cycle activity but relate to DNA damage-dependent activation of Wnt signaling, which in turn amplifies DNA damage checkpoint activation. The study shows that instructed enhancement of Wnt signaling increases radio-sensitivity of ISPCs, while inhibition of Wnt signaling decreases it. These results provide a proof of concept that cell intrinsic levels of Wnt signaling modulate the sensitivity of ISPCs to DNA damage and heterogeneity in Wnt activation in the stem cell niche contributes to the selection of ISPCs in the context of DNA damage.
Subject(s)
DNA Damage/physiology , Intestines/cytology , Radiation Tolerance/physiology , Stem Cells/metabolism , Wnt Signaling Pathway/physiology , Animals , Blotting, Western , Flow Cytometry , Fluorescent Antibody Technique , In Situ Hybridization , In Situ Nick-End Labeling , Mice , Mice, Inbred C57BL , Mice, Knockout , Microarray Analysis , Real-Time Polymerase Chain Reaction , Statistics, NonparametricABSTRACT
The causal role of aneuploidy in cancer initiation remains under debate since mutations of euploidy-controlling genes reduce cell fitness but aneuploidy strongly associates with human cancers. Telomerase activation allows immortal growth by stabilizing telomere length, but its role in aneuploidy survival has not been characterized. Here, we analyze the response of primary human cells and murine hematopoietic stem cells (HSCs) to aneuploidy induction and the role of telomeres and the telomerase in this process. The study shows that aneuploidy induces replication stress at telomeres leading to telomeric DNA damage and p53 activation. This results in p53/Rb-dependent, premature senescence of human fibroblast, and in the depletion of hematopoietic cells in telomerase-deficient mice. Endogenous telomerase expression in HSCs and enforced expression of telomerase in human fibroblasts are sufficient to abrogate aneuploidy-induced replication stress at telomeres and the consequent induction of premature senescence and hematopoietic cell depletion. Together, these results identify telomerase as an aneuploidy survival factor in mammalian cells based on its capacity to alleviate telomere replication stress in response to aneuploidy induction.
Subject(s)
Aneuploidy , Telomerase/metabolism , Telomere/metabolism , Animals , Cellular Senescence/genetics , Cellular Senescence/physiology , DNA Replication/genetics , DNA Replication/physiology , Hematopoietic Stem Cells/metabolism , Humans , Mice , Telomerase/genetics , Telomere/genetics , Tumor Suppressor Protein p53/metabolismABSTRACT
In acute lymphoblastic leukemia (ALL), central nervous system (CNS) involvement is a major clinical concern. Despite nondetectable CNS leukemia in many cases, prophylactic CNS-directed conventional intrathecal chemotherapy is required for relapse-free survival, indicating subclinical CNS manifestation in most patients. However, CNS-directed therapy is associated with long-term sequelae, including neurocognitive deficits and secondary neoplasms. Therefore, molecular mechanisms and pathways mediating leukemia-cell entry into the CNS need to be understood to identify targets for prophylactic and therapeutic interventions and develop alternative CNS-directed treatment strategies. In this study, we analyzed leukemia-cell entry into the CNS using a primograft ALL mouse model. We found that primary ALL cells transplanted onto nonobese diabetic/severe combined immunodeficiency mice faithfully recapitulated clinical and pathological features of meningeal infiltration seen in patients with ALL. ALL cells that had entered the CNS and were infiltrating the meninges were characterized by high expression of vascular endothelial growth factor A (VEGF). Although cellular viability, growth, proliferation, and survival of ALL cells were found to be independent of VEGF, transendothelial migration through CNS microvascular endothelial cells was regulated by VEGF. The importance of VEGF produced by ALL cells in mediating leukemia-cell entry into the CNS and leptomeningeal infiltration was further demonstrated by specific reduction of CNS leukemia on in vivo VEGF capture by the anti-VEGF antibody bevacizumab. Thus, we identified a mechanism of ALL-cell entry into the CNS, which by targeting VEGF signaling may serve as a novel strategy to control CNS leukemia in patients, replacing conventional CNS-toxic treatment.
Subject(s)
Central Nervous System Neoplasms/metabolism , Leukemic Infiltration/metabolism , Neoplasm Proteins/metabolism , Neoplasms, Experimental/metabolism , Precursor Cell Lymphoblastic Leukemia-Lymphoma/metabolism , Vascular Endothelial Growth Factor A/metabolism , Animals , Bevacizumab/pharmacology , Cell Survival/drug effects , Central Nervous System Neoplasms/drug therapy , Central Nervous System Neoplasms/pathology , Endothelial Cells/metabolism , Endothelial Cells/pathology , Heterografts , Humans , Leukemic Infiltration/drug therapy , Leukemic Infiltration/pathology , Mice , Mice, Inbred NOD , Mice, SCID , Neoplasm Proteins/antagonists & inhibitors , Neoplasm Transplantation , Neoplasms, Experimental/drug therapy , Neoplasms, Experimental/pathology , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Precursor Cell Lymphoblastic Leukemia-Lymphoma/pathology , Transendothelial and Transepithelial Migration/drug effects , Vascular Endothelial Growth Factor A/antagonists & inhibitorsABSTRACT
Liver cholestasis is a chronic liver disease and a major health problem worldwide. Cholestasis is characterised by a decrease in bile flow due to impaired secretion by hepatocytes or by obstruction of bile flow through intra- or extrahepatic bile ducts. Thereby cholestasis can induce ductal proliferation, hepatocyte injury and liver fibrosis. Notch signalling promotes the formation and maturation of bile duct structures. Here we investigated the liver regeneration process in the context of cholestasis induced by disruption of the Notch signalling pathway. Liver-specific deletion of recombination signal binding protein for immunoglobulin kappa j region (Rbpj), which represents a key regulator of Notch signalling, induces severe cholestasis through impaired intra-hepatic bile duct (IHBD) maturation, severe necrosis and increased lethality. Deregulation of the biliary compartment and cholestasis are associated with the change of several signalling pathways including a Kyoto Encyclopedia of Genes and Genomes (KEGG) gene set representing the Hippo pathway, further yes-associated protein (YAP) activation and upregulation of SRY (sex determining region Y)-box 9 (SOX9), which is associated with transdifferentiation of hepatocytes. SOX9 upregulation in cholestatic liver injury in vitro is independent of Notch signalling. We could comprehensively address that in vivo Rbpj depletion is followed by YAP activation, which influences the transdifferentiation of hepatocytes and thereby contributing to liver regeneration.
Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Cholestasis/metabolism , Liver Regeneration/physiology , Phosphoproteins/metabolism , Adaptor Proteins, Signal Transducing/genetics , Animals , Bile Ducts/metabolism , Bile Ducts/physiology , Blotting, Western , Cell Cycle Proteins , Cell Transdifferentiation/genetics , Cell Transdifferentiation/physiology , Cells, Cultured , Cholestasis/genetics , Hepatocytes/cytology , Hepatocytes/metabolism , Liver Regeneration/genetics , Male , Mice , Phosphoproteins/genetics , Signal Transduction/genetics , Signal Transduction/physiology , YAP-Signaling ProteinsABSTRACT
UNLABELLED: Over the past years growing knowledge about biological processes and pathways revealed complex interaction networks involving many genes. In order to understand these networks, analysis of differential expression has continuously moved from single genes towards the study of gene sets. Various approaches for the assessment of gene sets have been developed in the context of gene set analysis (GSA). These approaches are bridging the gap between raw measurements and semantically meaningful terms.We present a novel approach for assessing uncertainty in the definition of gene sets. This is an essential step when new gene sets are constructed from domain knowledge or given gene sets are suspected to be affected by uncertainty. Quantification of uncertainty is implemented in the R-package GiANT. We also included widely used GSA methods, embedded in a generic framework that can readily be extended by custom methods. The package provides an easy to use front end and allows for fast parallelization. AVAILABILITY AND IMPLEMENTATION: The package GiANT is available on CRAN. CONTACTS: hans.kestler@leibniz-fli.de or hans.kestler@uni-ulm.de.