bims-malgli Biomed News
on Biology of malignant gliomas
Issue of 2020–07–05
fourteen papers selected by
Oltea Sampetrean, Keio University
  1. Integrated pharmaco-proteogenomics defines two subgroups in isocitrate dehydrogenase wild-type glioblastoma with prognostic and therapeutic opportunities.
  2. Protein Sumoylation with SUMO1 Promoted by Pin1 in Glioma Stem Cells Augments Glioblastoma Malignancy.
  3. Radiation with STAT3 blockade triggers dendritic cell-T cell interactions in the glioma microenvironment and therapeutic efficacy.
  4. Emerging Immunotherapies for Malignant Glioma: From Immunogenomics to Cell Therapy.
  5. Glioma escape signature and clonal development under immune pressure.
  6. Everolimus improves the efficacy of dasatinib in PDGFRα-driven glioma.
  7. Fusing the Genetic Landscape of Infantile High-Grade Gliomas.
  8. Multimodal single-cell analysis reveals distinct radioresistant stem-like and progenitor cell populations in murine glioma.
  9. Utility of Human-Derived Models for Glioblastoma.
  10. Antiangiogenic Targets for Glioblastoma Therapy from a Pre-Clinical Approach, Using Nanoformulations.
  11. Poly(ADP-ribose) glycohydrolase inhibition sequesters NAD+ to potentiate the metabolic lethality of alkylating chemotherapy in IDH mutant tumor cells.
  12. GL261 luciferase-expressing cells elicit an anti-tumor immune response: an evaluation of murine glioma models.
  13. BET bromodomain inhibitor HMBA synergizes with MEK inhibition in treatment of malignant glioma.
  14. Molecular Characterization of Astrocytoma Progression Towards Secondary Glioblastomas Utilizing Patient-Matched Tumor Pairs.
  1. Nat Commun. 2020 Jul 03. 11(1): 3288
    Integrated pharmaco-proteogenomics defines two subgroups in isocitrate dehydrogenase wild-type glioblastoma with prognostic and therapeutic opportunities.
    Sejin Oh, Jeonghun Yeom, Hee Jin Cho, Ju-Hwa Kim, Seon-Jin Yoon, Hakhyun Kim, Jason K Sa, Shinyeong Ju, Hwanho Lee, Myung Joon Oh, Wonyeop Lee, Yumi Kwon, Honglan Li, Seunghyuk Choi, Jang Hee Han, Jong Hee Chang, Eunsuk Choi, Jayeon Kim, Nam-Gu Her, Se Hoon Kim, Seok-Gu Kang, Eunok Paek, Do-Hyun Nam, Cheolju Lee, Hyun Seok Kim.
      The prognostic and therapeutic relevance of molecular subtypes for the most aggressive isocitrate dehydrogenase 1/2 (IDH) wild-type glioblastoma (GBM) is currently limited due to high molecular heterogeneity of the tumors that impedes patient stratification. Here, we describe a distinct binary classification of IDH wild-type GBM tumors derived from a quantitative proteomic analysis of 39 IDH wild-type GBMs as well as IDH mutant and low-grade glioma controls. Specifically, GBM proteomic cluster 1 (GPC1) tumors exhibit Warburg-like features, neural stem-cell markers, immune checkpoint ligands, and a poor prognostic biomarker, FKBP prolyl isomerase 9 (FKBP9). Meanwhile, GPC2 tumors show elevated oxidative phosphorylation-related proteins, differentiated oligodendrocyte and astrocyte markers, and a favorable prognostic biomarker, phosphoglycerate dehydrogenase (PHGDH). Integrating these proteomic features with the pharmacological profiles of matched patient-derived cells (PDCs) reveals that the mTORC1/2 dual inhibitor AZD2014 is cytotoxic to the poor prognostic PDCs. Our analyses will guide GBM prognosis and precision treatment strategies.
    DOI:  https://doi.org/10.1038/s41467-020-17139-y
  2. Neuro Oncol. 2020 Jun 27. pii: noaa150. [Epub ahead of print]
    Protein Sumoylation with SUMO1 Promoted by Pin1 in Glioma Stem Cells Augments Glioblastoma Malignancy.
    Aili Zhang, Weiwei Tao, Kui Zhai, Xiaoguang Fang, Zhi Huang, Jennifer S Yu, Andrew E Solan, Jeremy N Rich, Wenchao Zhou, Shideng Bao.
       BACKGROUND: The tumorigenic potential of glioma stem cells (GSCs) is associated with multiple reversible molecular alternations, but the role of post-translational protein sumoylation in GSCs has not been elucidated. The development of GSC-targeting drugs relies on the discovery of GSC-preferential molecular modifications and the relevant signaling pathways. In this work, we investigated the protein sumoylation status, the major sumoylated substrate and the key regulatory enzyme in GSCs to explore the therapeutic potential of disrupting protein sumoylation for glioblastoma (GBM) treatment.
    METHODS: Patient-derived GSCs, primary GBM sections, and intracranial GBM xenografts were used to determine protein sumoylation and the related molecular mechanisms by immunoblot, quantitative PCR, immunoprecipitation, immunofluorescence and immunohistochemistry. Orthotopic GBM xenograft models were applied to investigate the inhibition of tumor growth by disrupting protein sumoylation with shRNAs or molecular inhibitors.
    RESULTS: We show that high levels of SUMO1- but not SUMO2/3-modified sumoylation are preferentially present in GSCs. The promyelocytic leukaemia protein (PML) is a major SUMO1-sumoylated substrate in GSCs, whose sumoylation facilitates its interaction with c-Myc to stabilize c-Myc proteins. The prolyl-isomerase Pin1 is preferentially expressed in GSCs and functions as the key enzyme to promote SUMO1-sumoylation. Disruption of SUMO1-sumoylation by Pin1 silencing with shRNAs or inhibition with its inhibitor Juglone markedly abrogated GSC maintenance and mitigated GSC-driven tumor growth.
    CONCLUSIONS: Our findings indicate that high SUMO1-modified protein sumoylation as a feature of GSCs is critical for GSC maintenance, suggesting that targeting SUMO1-sumoylation may effectively improve GBM treatment.
    Keywords:  Glioma stem cells; PML; Pin1; Post-translational modification; Protein sumoylation
    DOI:  https://doi.org/10.1093/neuonc/noaa150
  3. Clin Cancer Res. 2020 Jun 30. pii: clincanres.4092.2019. [Epub ahead of print]
    Radiation with STAT3 blockade triggers dendritic cell-T cell interactions in the glioma microenvironment and therapeutic efficacy.
    Martina Ott, Cynthia Kassab, Anantha Marisetty, Yuuri Hashimoto, Jun Wei, Daniel B Zamler, Jia-Shiun Leu, Karl-Heinz Tomaszowski, Aria Sabbagh, Dexing Fang, Pravesh Gupta, Waldemar Priebe, Rafal Zielinski, Jared K Burks, James P Long, Ling-Yuan Kong, Gregory N Fuller, John F de Groot, Erik P Sulman, Amy B Heimberger.
       BACKGROUND: Patients with central nervous system (CNS) tumors are typically treated with radiation therapy, but this is not curative and results in the upregulation of phosphorylated signal transducer and activator of transcription 3 (p-STAT3), which drives invasion, angiogenesis, and immune suppression. Therefore, we investigated the combined effect of an inhibitor of STAT3 and whole-brain radiation therapy (WBRT) in a murine model of glioma.
    METHODS: C57BL/6 mice underwent intracerebral implantation of GL261 glioma cells, WBRT, and treatment with WP1066, a blood-brain barrier (BBB)-penetrant inhibitor of the STAT3 pathway, or the two in combination. The role of the immune system was evaluated using tumor rechallenge strategies, immune incompetent backgrounds, immunofluorescence, immune phenotyping of tumor-infiltrating immune cells (via flow cytometry), and nanostring gene expression analysis of 770 immune-related genes from immune cells, including those directly isolated from the tumor microenvironment.
    RESULTS: The combination of WP1066 and WBRT resulted in long-term survivors and enhanced median survival time relative to monotherapy in the GL261 glioma model (combination vs. control p<0.0001). Immunological memory appeared to be induced, because mice were protected during subsequent tumor rechallenge. The therapeutic effect of the combination was completely lost in immune incompetent animals. Nanostring analysis and immunofluorescence revealed immunological reprograming in the CNS tumor microenvironment specifically affecting dendritic-cell antigen presentation and T cell effector functions.
    CONCLUSION: This study indicates that the combination of STAT3 inhibition and WBRT enhances the therapeutic effect against gliomas in the CNS by inducing dendritic cell and T cell interactions in the CNS tumor.
    DOI:  https://doi.org/10.1158/1078-0432.CCR-19-4092
  4. Neuro Oncol. 2020 Jul 02. pii: noaa154. [Epub ahead of print]
    Emerging Immunotherapies for Malignant Glioma: From Immunogenomics to Cell Therapy.
    Gavin P Dunn, Timothy F Cloughesy, Marcela V Maus, Robert M Prins, David A Reardon, Adam M Sonabend.
      As immunotherapy assumes a central role in the management of many cancers, ongoing work is directed at understanding whether immune-based treatments will be successful in patients with glioblastoma (GBM). Despite several large studies conducted in the last several years, there remain no FDA approved immunotherapies in this patient population. Nevertheless, there are a range of exciting new approaches being applied to GBM, all of which may not only allow us to develop new treatments but also help us understand fundamental features of the immune response in the central nervous system. In this review, we summarize new developments in the application of immune checkpoint blockade, from biomarker-driven patient selection to the timing of treatment. Moreover, we summarize novel work in personalized immune-oncology be reviewing work in cancer immunogenomics-drive neoantigen vaccine studies. Finally, we discuss cell therapy efforts by reviewing the current state of chimeric antigen receptor (CAR) T cell therapy.
    Keywords:  CNS immunosurveillance; cancer immunogenomics; glioblastoma; neoantigen; personalized vaccine
    DOI:  https://doi.org/10.1093/neuonc/noaa154
  5. J Clin Invest. 2020 Jun 30. pii: 138760. [Epub ahead of print]
    Glioma escape signature and clonal development under immune pressure.
    Cecile L Maire, Malte Mohme, Michael Bockmayr, Krystian D Fita, Kristoffer Riecken, Daniela Börnigen, Malik Alawi, Antonio Virgilio Failla, Katharina Kolbe, Svenja Zapf, Mareike Holz, Katrin Neumann, Lasse Dührsen, Tobias Lange, Boris Fehse, Manfred Westphal, Katrin Lamszus.
      Immunotherapeutic strategies are increasingly important in neuro-oncology and the elucidation of escape mechanisms which lead to treatment resistance is crucial. We investigated the impact of immune pressure on the clonal dynamics and immune escape signature by comparing glioma growth in immunocompetent versus immunodeficient mice. Glioma-bearing wildtype and Pd-1-/- mice survived significantly longer than immunodeficient Pfp-/- Rag2-/- mice. While tumors in Pfp-/- Rag2-/- mice were highly polyclonal, immunoedited tumors in WT and Pd-1-/- mice displayed reduced clonality with emergence of immune escape clones. Tumor cells in wildtype mice were distinguished by an interferon-γ-mediated response signature with upregulation of genes involved in immunosuppression. Tumor-infiltrating stromal cells, which include macrophages/microglia, contributed even stronger to the immunosuppressive signature than the actual tumor cells. The identified murine immune escape signature was reflected in human patients and correlated with poor survival. In conclusion, immune pressure profoundly shapes the clonal composition and gene regulation in malignant gliomas.
    Keywords:  Brain cancer; Immunology; Oncology
    DOI:  https://doi.org/10.1172/JCI138760
  6. J Clin Invest. 2020 Jun 30. pii: 133310. [Epub ahead of print]
    Everolimus improves the efficacy of dasatinib in PDGFRα-driven glioma.
    Zachary Miklja, Viveka Nand Yadav, Rodrigo T Cartaxo, Ruby Siada, Chase C Thomas, Jessica R Cummings, Brendan Mullan, Stefanie Stallard, Alyssa Paul, Amy K Bruzek, Kyle Wierzbicki, Tao Yang, Taylor Garcia, Ian Wolfe, Marcia Leonard, Patricia L Robertson, Hugh Jl Garton, Daniel R Wahl, Hemant A Parmar, Jann N Sarkaria, Cassie Kline, Sabine Mueller, Theodore Nicolaides, Chana Glasser, Sarah E S Leary, Sriram Venneti, Chandan Kumar-Sinha, Arul M Chinnaiyan, Rajen Mody, Manjunath P Pai, Timothy N Phoenix, Bernard L Marini, Carl Koschmann.
       BACKGROUND: Pediatric and adult high-grade glioma (HGG) frequently harbor PDGFRA alterations. We hypothesized that co-treatment with everolimus may improve the efficacy of dasatinib in PDGFRα-driven glioma through combinatorial synergism and increased tumor accumulation of dasatinib.
    METHODS: Dose response, synergism studies, P-gp inhibition and pharmacokinetic studies were performed on in vitro and in vivo human and mouse models of HGG. Six patients with recurrent PDGFRα-driven glioma were treated with dasatinib and everolimus.
    RESULTS: Dasatinib effectively inhibited the proliferation of mouse and human primary HGG cells with a variety of PDGFRA alterations. Dasatinib exhibited synergy with everolimus in the treatment of HGG cells at low nanomolar concentrations of both agents, with reduction in mTOR signaling that persists after dasatinib treatment alone. Prolonged exposure to everolimus significantly improved the CNS retention of dasatinib and extended survival of PPK tumor bearing mice. Pediatric patients (n=6) with glioma tolerated this combination without significant adverse events. Recurrent patients (n=4) demonstrated median overall survival of 8.5 months.
    CONCLUSION: Efficacy of dasatinib treatment of PDGFRα-driven HGG is improved with everolimus and suggests a promising route for improving targeted therapy for this patient population.
    TRIAL REGISTRATION: ClinicalTrials.gov NCT03352427Funding: The authors thank the patients and their families for participation in this study. CKis supported by NIH/NINDS K08-NS099427-01, the University of Michigan Chad Carr Pediatric Brain Tumor Center, the Chad Tough Foundation, Hyundai Hope on Wheels, Catching up With Jack, Prayers from Maria Foundation, U CAN-CER VIVE FOUNDATION, Morgan Behen Golf Classic, and the DIPG Collaborative. The PEDS-MIONCOSEQ study was supported by grant 1UM1HG006508 from the National Institutes of Health Clinical Sequencing Exploratory Research Award (PI: Arul Chinnaiyan).
    Keywords:  Brain cancer; Molecular biology; Oncology; Pharmacology
    DOI:  https://doi.org/10.1172/JCI133310
  7. Cancer Discov. 2020 Jul;10(7): 904-906
    Fusing the Genetic Landscape of Infantile High-Grade Gliomas.
    Frank Szulzewsky, Patrick J Cimino.
      In this issue of Cancer Discovery, Clarke and colleagues define the genetic landscape of infantile cerebral high-grade gliomas, which frequently contain alterations in the MAPK pathway, as well as recurrent gene fusions in receptor tyrosine kinases (ALK, ROS1, MET) and neurotrophic receptor kinases (NTRK1-3). Combining their multi-omic profiling data with functional preclinical and clinical studies, this large multi-institutional study provides strong rationale for future classification and molecular subtype-specific therapeutic management of infantile high-grade glioma.See related article by Clarke et al., p. 942.
    DOI:  https://doi.org/10.1158/2159-8290.CD-20-0495
  8. Glia. 2020 Jul 04.
    Multimodal single-cell analysis reveals distinct radioresistant stem-like and progenitor cell populations in murine glioma.
    Jes Alexander, Quincey C LaPlant, Siobhan S Pattwell, Frank Szulzewsky, Patrick J Cimino, Francesca P Caruso, Pietro Pugliese, Zhihong Chen, Florence Chardon, Andrew J Hill, Cailyn Spurrell, Dakota Ahrendsen, Alexander Pietras, Lea M Starita, Dolores Hambardzumyan, Antonio Iavarone, Jay Shendure, Eric C Holland.
      Radiation therapy is part of the standard of care for gliomas and kills a subset of tumor cells, while also altering the tumor microenvironment. Tumor cells with stem-like properties preferentially survive radiation and give rise to glioma recurrence. Various techniques for enriching and quantifying cells with stem-like properties have been used, including the fluorescence activated cell sorting (FACS)-based side population (SP) assay, which is a functional assay that enriches for stem-like tumor cells. In these analyses, mouse models of glioma have been used to understand the biology of this disease and therapeutic responses, including the radiation response. We present combined SP analysis and single-cell RNA sequencing of genetically-engineered mouse models of glioma to show a time course of cellular response to radiation. We identify and characterize two distinct tumor cell populations that are inherently radioresistant and also distinct effects of radiation on immune cell populations within the tumor microenvironment.
    Keywords:  SP analysis; glioma; glioma stem cells; myeloid cells; radiation response; radioresistance; single-cell RNA sequencing
    DOI:  https://doi.org/10.1002/glia.23866
  9. Cancer Discov. 2020 Jul;10(7): 907-909
    Utility of Human-Derived Models for Glioblastoma.
    Xujun Luo, William A Weiss.
      In this issue, Pine and colleagues compared single-cell RNA-sequencing data across four distinct types of glioblastoma stem cell-derived tumor models, reinforcing the importance of a three-dimensional microenvironment for accurate recapitulation of cellular states.See related article by Pine et al., p. 964.
    DOI:  https://doi.org/10.1158/2159-8290.CD-20-0493
  10. Int J Mol Sci. 2020 Jun 24. pii: E4490. [Epub ahead of print]21(12):
    Antiangiogenic Targets for Glioblastoma Therapy from a Pre-Clinical Approach, Using Nanoformulations.
    Gabriel Nery de Albuquerque Rego, Arielly da Hora Alves, Mariana Penteado Nucci, Javier Bustamante Mamani, Fernando Anselmo de Oliveira, Lionel Fernel Gamarra.
      Glioblastoma (GBM) is the most aggressive tumor type whose resistance to conventional treatment is mediated, in part, by the angiogenic process. New treatments involving the application of nanoformulations composed of encapsulated drugs coupled to peptide motifs that direct drugs to specific targets triggered in angiogenesis have been developed to reach and modulate different phases of this process. We performed a systematic review with the search criterion (Glioblastoma OR Glioma) AND (Therapy OR Therapeutic) AND (Nanoparticle) AND (Antiangiogenic OR Angiogenesis OR Anti-angiogenic) in Pubmed, Scopus, and Cochrane databases, in which 312 articles were identified; of these, only 27 articles were included after selection and analysis of eligibility according to the inclusion and exclusion criteria. The data of the articles were analyzed in five contexts: the characteristics of the tumor cells; the animal models used to induce GBM for antiangiogenic treatment; the composition of nanoformulations and their physical and chemical characteristics; the therapeutic anti-angiogenic process; and methods for assessing the effects on antiangiogenic markers caused by therapies. The articles included in the review were heterogeneous and varied in practically all aspects related to nanoformulations and models. However, there was slight variance in the antiangiogenic effect analysis. CD31 was extensively used as a marker, which does not provide a view of the effects on the most diverse aspects involved in angiogenesis. Therefore, the present review highlighted the need for standardization between the different approaches of antiangiogenic therapy for the GBM model that allows a more effective meta-analysis and that helps in future translational studies.
    Keywords:  GBM; angiogenesis; antiangiogenic therapy; glioblastoma; nanomedicine; nanoparticle; nanotherapy; tumor targeting
    DOI:  https://doi.org/10.3390/ijms21124490
  11. Cancer Discov. 2020 Jun 30. pii: CD-20-0226. [Epub ahead of print]
    Poly(ADP-ribose) glycohydrolase inhibition sequesters NAD+ to potentiate the metabolic lethality of alkylating chemotherapy in IDH mutant tumor cells.
    Hiroaki Nagashima, Christine K Lee, Kensuke Tateishi, Fumi Higuchi, Megha Subramanian, Seamus Rafferty, Lisa Melamed, Julie J Miller, Hiroaki Wakimoto, Daniel P Cahill.
      Nicotinamide adenine dinucleotide (NAD+) is an essential cofactor metabolite and is the currency of metabolic transactions critical for cell survival. Depending on tissue context and genotype, cancer cells have unique dependencies on NAD+ metabolic pathways. Poly(ADP-ribose) polymerases (PARPs) catalyze oligomerization of NAD+ monomers into poly(ADP-ribose) (PAR) chains during cellular response to alkylating chemotherapeutics, including procarbazine or temozolomide. Here, we find that, in endogenous IDH1 mutant tumor models, alkylator-induced cytotoxicity is markedly augmented by pharmacologic inhibition or genetic knockout of the PAR breakdown enzyme poly(ADP-ribose) glycohydrolase (PARG). Both in vitro and in vivo, we observe that concurrent alkylator and PARG inhibition depletes freely available NAD+ by preventing PAR breakdown, resulting in NAD+ sequestration and collapse of metabolic homeostasis. This effect reversed with NAD+ rescue supplementation, confirming the mechanistic basis of cytotoxicity. Thus, alkylating chemotherapy exposes a genotype-specific metabolic weakness in tumor cells that can be exploited by PARG inactivation.
    DOI:  https://doi.org/10.1158/2159-8290.CD-20-0226
  12. Sci Rep. 2020 Jul 03. 10(1): 11003
    GL261 luciferase-expressing cells elicit an anti-tumor immune response: an evaluation of murine glioma models.
    Victoria E Sanchez, John P Lynes, Stuart Walbridge, Xiang Wang, Nancy A Edwards, Anthony K Nwankwo, Hannah P Sur, Gifty A Dominah, Arnold Obungu, Nicholas Adamstein, Pradeep K Dagur, Dragan Maric, Jeeva Munasinghe, John D Heiss, Edjah K Nduom.
      Preclinical models that reliably recapitulate the immunosuppressive properties of human gliomas are essential to assess immune-based therapies. GL261 murine glioma cells are widely used as a syngeneic animal model of glioma, however, it has become common practice to transfect these cells with luciferase for fluorescent tumor tracking. The aim of this study was to compare the survival of mice injected with fluorescent or non-fluorescent GL261 cells and characterize the differences in their tumor microenvironment. Mice were intracranially implanted with GL261, GL261 Red-FLuc or GL261-Luc2 cells at varying doses. Cytokine profiles were evaluated by proteome microarray and Kaplan-Meier survival analysis was used to determine survival differences. Median survival for mice implanted with 5 × 104 GL261 cells was 18 to 21 days. The GL261 Red-FLuc implanted mice cells did not reach median survival at any tumor dose. Mice injected with 3 × 105 GL261-Luc2 cells reached median survival at 23 days. However, median survival was significantly prolonged to 37 days in mice implanted with 5 × 104 GL261-Luc2 cells. Additionally, proteomic analyses revealed significantly elevated inflammatory cytokines in the supernatants of the GL261 Red-FLuc cells and GL261-Luc2 cells. Our data suggest that GL261 Red-FLuc and GL261-Luc2 murine models elicit an anti-tumor immune response by increasing pro-inflammatory modulators.
    DOI:  https://doi.org/10.1038/s41598-020-67411-w
  13. Epigenetics. 2020 Jun 30. 1-10
    BET bromodomain inhibitor HMBA synergizes with MEK inhibition in treatment of malignant glioma.
    Elisa Funck-Brentano, Dzeneta Vizlin-Hodzic, Jonas A Nilsson, Lisa M Nilsson.
      (1) Background: BET bromodomain proteins regulate transcription by binding acetylated histones and attracting key factors for, e.g., transcriptional elongation. BET inhibitors have been developed to block pathogenic processes such as cancer and inflammation. Despite having potent biological activities, BET inhibitors have still not made a breakthrough in clinical use for treating cancer. Multiple resistance mechanisms have been proposed but thus far no attempts to block this in glioma has been made. (2) Methods: Here, we have conducted a pharmacological synergy screen in glioma cells to search for possible combination treatments augmenting the apoptotic response to BET inhibitors. We first used HMBA, a compound that was developed as a differentiation therapy four decades ago but more recently was shown to primarily inhibit BET bromodomain proteins. Data was also generated using other BET inhibitors. (3) Results: In the synergy screen, we discovered that several MEK inhibitors can enhance apoptosis in response to HMBA in rat and human glioma cells in vitro as well as in vivo xenografts. The combination is not unique to HMBA but also other BET inhibitors such as JQ1 and I-BET-762 can synergize with MEK inhibitors. (4) Conclusions: Our findings validate a combination therapy previously demonstrated to exhibit anti-cancer activities in multiple other tumour types but which appears to have been lost in translation to the clinic.
    Keywords:  BET bromodomain protein; glioma; hexamethylene bisacetamide
    DOI:  https://doi.org/10.1080/15592294.2020.1786319
  14. Cancers (Basel). 2020 Jun 26. pii: E1696. [Epub ahead of print]12(6):
    Molecular Characterization of Astrocytoma Progression Towards Secondary Glioblastomas Utilizing Patient-Matched Tumor Pairs.
    Michael Seifert, Gabriele Schackert, Achim Temme, Evelin Schröck, Andreas Deutsch, Barbara Klink.
      Astrocytomas are primary human brain tumors including diffuse or anaplastic astrocytomas that develop towards secondary glioblastomas over time. However, only little is known about molecular alterations that drive this progression. We measured multi-omics profiles of patient-matched astrocytoma pairs of initial and recurrent tumors from 22 patients to identify molecular alterations associated with tumor progression. Gene copy number profiles formed three major subcluters, but more than half of the patient-matched astrocytoma pairs differed in their gene copy number profiles like astrocytomas from different patients. Chromosome 10 deletions were not observed for diffuse astrocytomas, but occurred in corresponding recurrent tumors. Gene expression profiles formed three other major subclusters and patient-matched expression profiles were much more heterogeneous than their copy number profiles. Still, recurrent tumors showed a strong tendency to switch to the mesenchymal subtype. The direct progression of diffuse astrocytomas to secondary glioblastomas showed the largest number of transcriptional changes. Astrocytoma progression groups were further distinguished by signaling pathway expression signatures affecting cell division, interaction and differentiation. As expected, IDH1 was most frequently mutated closely followed by TP53, but also MUC4 involved in the regulation of apoptosis and proliferation was frequently mutated. Astrocytoma progression groups differed in their mutation frequencies of these three genes. Overall, patient-matched astrocytomas can differ substantially within and between patients, but still molecular signatures associated with the progression to secondary glioblastomas exist and should be analyzed for their potential clinical relevance in future studies.
    Keywords:  astrocytomas; cancer genomics; patient-matched astrocytoma pairs; secondary glioblastoma; stage-wise astrocytoma development
    DOI:  https://doi.org/10.3390/cancers12061696
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