Overexpression of Lin28A in neural progenitor cells in vivo does not lead to brain tumor formation but results in reduced spine density

AbstractLIN28A overexpression has been identified in malignant brain tumors called embryonal tumors with multilayered rosettes (ETMR) but its specific role during brain development remains largely unknown. Radial glia cells of the ventricular zone (VZ) are proposed as a cell of origin for ETMR. We asked whether an overexpression of LIN28A in such cells might affect brain development or result in the formation of brain tumors.Constitutive overexpression of LIN28A in hGFAP-cre::lsl-Lin28A (GL) mice led to a transient increase of proliferation in the cortical VZ at embryonic stages but no postnatal brain tumor formation. Postnatally, GL mice displayed a pyramidal cell layer dispersion of the hippocampus and altered spine and dendrite morphology, including reduced dendritic spine densities in the hippocampus and cortex. GL mice displayed hyperkinetic activity and differential quantitative MS-based proteomics revealed altered time dependent molecular functions regarding mRNA processing and spine morphogenesis. Phosphoproteomic analyses indicated a downregulation of mTOR pathway modulated proteins such as Map1b being involved in microtubule dynamics.In conclusion, we show that Lin28A overexpression transiently increases proliferation of neural precursor cells but it is not sufficient to drive brain tumors in vivo. In contrast, Lin28A impacts on protein abundancy patterns related to spine morphogenesis and phosphorylation levels of proteins involved in microtubule dynamics, resulting in decreased spine densities of neurons in the hippocampus and cortex as well as in altered behavior. Our work provides new insights into the role of LIN28A for neuronal morphogenesis and development and may reveal future targets for treatment of ETMR patients.

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BIOM-10. PRECLINICAL PLATFORM FOR THE IDENTIFICATION OF DEUTERIUM MAGNETIC RESONANCE SPECTROSCOPY-BASED BIOMARKERS OF BRAIN TUMOR METABOLISM

Neuro-Oncology ◽

10.1093/neuonc/noab196.041 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi12-vi12

Author(s):

Georgios Batsios ◽

Meryssa Tran ◽

Céline Taglang ◽

Anne Marie Gillespie ◽

Sabrina Ronen ◽

...

Keyword(s):

Brain Tumor ◽

Magnetic Resonance ◽

Magnetic Resonance Spectroscopy ◽

Brain Tumors ◽

Treatment Response ◽

Lactate Production ◽

Cell Suspensions ◽

Response To Therapy ◽

Resonance Spectroscopy

Abstract Metabolic reprogramming is a fundamental hallmark of cancer, which can be exploited for non-invasive tumor imaging. Deuterium magnetic resonance spectroscopy (2H-MRS) recently emerged as a novel, translational method of interrogating flux from 2H-labeled substrates to metabolic products. However, to date, preclinical studies have been performed in vivo, an endeavor which suffers from low-throughput and potential wastage of animal life, especially when considering studies of treatment response. Developing in vitro assays for monitoring metabolism of 2H-labeled substrates will enhance throughput, lead to the rapid evaluation of new 2H-based probes and enable identification of treatment response biomarkers, thereby allowing the best 2H-based probes to be translated for further in vivo assessment. The goal of this study was to develop a preclinical cell-based platform for quantifying metabolism of 2H-labeled probes in brain tumor models. Since the Warburg effect, which is characterized by elevated glycolytic production of lactate, is a metabolic phenotype of cancer, including brain tumors, we examined metabolism of 2H-glucose or 2H-pyruvate in patient-derived glioblastoma (GBM6) and oligodendroglioma (BT88) cells and compared to normal human astrocytes (NHACONTROL). Following incubation in media containing [6,6’-2H]glucose or [U-2H]pyruvate, 2H-MR spectra obtained from live cell suspensions showed elevated 2H-lactate production in GBM6 and BT88 cells relative to NHACONTROL. Importantly, 2H-lactate production from [6,6’-2H]glucose or from [U-2H]pyruvate was reduced in GBM6 or BT88 cells subjected to irradiation and temozolomide, which is standard of care for glioma patients, pointing to the utility of this method for detecting response to therapy. Collectively, we have, for the first time, demonstrated the ability to quantify metabolism of 2H-MRS probes in live cell suspensions and validated the utility of our assay for differentiating tumor from normal cells and assessing response to therapy. Our studies will expedite the identification of novel 2H-MRS probes for imaging brain tumors and potentially other types of cancer.

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Generation of Murine Xenograft Models of Brain Tumors from Primary Human Tissue for In Vivo Analysis of the Brain Tumor-Initiating Cell

Stem Cells and Tissue Repair - Methods in Molecular Biology ◽

10.1007/978-1-4939-1435-7_4 ◽

2014 ◽

pp. 37-49 ◽

Cited By ~ 3

Author(s):

Maleeha Qazi ◽

Aneet Mann ◽

Randy van Ommeren ◽

Chitra Venugopal ◽

Nicole McFarlane ◽

...

Keyword(s):

Brain Tumor ◽

Brain Tumors ◽

Human Tissue ◽

In Vivo Analysis ◽

Xenograft Models ◽

The Brain ◽

Tumor Initiating Cell

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Dab2IP Regulates Neuronal Positioning, Rap1 Activity and Integrin Signaling in the Developing Cortex

Developmental Neuroscience ◽

10.1159/000369092 ◽

2015 ◽

Vol 37 (2) ◽

pp. 131-141 ◽

Cited By ~ 7

Author(s):

Shuhong Qiao ◽

Ramin Homayouni

Keyword(s):

Brain Development ◽

Cortical Neurons ◽

Ventricular Zone ◽

Physiological Role ◽

Immunohistochemical Analysis ◽

Superficial Layer ◽

Tumor Formation ◽

Intermediate Zone ◽

Cortical Plate ◽

Integrin Signaling

Dab2IP (DOC-2/DAB2 interacting protein) is a GTPase-activating protein which is involved in various aspects of brain development in addition to its roles in tumor formation and apoptosis in other systems. In this study, we carefully examined the expression profile of Dab2IP and investigated its physiological role during brain development using a Dab2IP-knockdown (KD) mouse model created by retroviral insertion of a LacZ-encoding gene-trapping cassette. LacZ staining revealed that Dab2IP is expressed in the ventricular zone as well as the cortical plate and the intermediate zone. Immunohistochemical analysis showed that Dab2IP protein is localized in the leading process and proximal cytoplasmic regions of migrating neurons in the intermediate zone. Bromodeoxyuridine birth dating experiments in combination with immunohistochemical analysis using layer-specific markers showed that Dab2IP is important for proper positioning of a subset of layer II-IV neurons in the developing cortex. Notably, neuronal migration was not completely disrupted in the cerebral cortex of Dab2IP-KD mice and disruption of migration was not strictly layer specific. Previously, we found that Dab2IP regulates multipolar transition in cortical neurons. Others have shown that Rap1 regulates the transition from multipolar to bipolar morphology in migrating postmitotic neurons through N-cadherin signaling and somal translocation in the superficial layer of the cortical plate through integrin signaling. Therefore, we examined whether Rap1 and integrin signaling were affected in Dab2IP-KD brains. We found that Dab2IP-KD resulted in higher levels of activated Rap1 and integrin in the developing cortex. Taken together, our results suggest that Dab2IP plays an important role in the migration and positioning of a subpopulation of later-born (layers II-IV) neurons, likely through the regulation of Rap1 and integrin signaling.

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In vivo validation of tissue segmentation based on a 3D feature map using both a hamster brain tumor model and stereotactically guided biopsy of brain tumors in man

Journal of Magnetic Resonance Imaging ◽

10.1002/jmri.1880080410 ◽

1998 ◽

Vol 8 (4) ◽

pp. 814-819 ◽

Cited By ~ 9

Author(s):

Simon Vinitski ◽

Carlos Gonzalez ◽

David Andrews ◽

Robert Knobler ◽

Mark Curtis ◽

...

Keyword(s):

Brain Tumor ◽

Brain Tumors ◽

Tumor Model ◽

Tissue Segmentation ◽

Feature Map ◽

Guided Biopsy ◽

Brain Tumor Model ◽

In Vivo Validation

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The Methanol Extract ofAngelica sinensisInduces Cell Apoptosis and Suppresses Tumor Growth in Human Malignant Brain Tumors

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2013/394636 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 5

Author(s):

Yu-Ling Lin ◽

Wen-Lin Lai ◽

Horng-jyh Harn ◽

Pei-Hsiu Hung ◽

Ming-Chang Hsieh ◽

...

Keyword(s):

Cell Cycle ◽

Brain Tumor ◽

Brain Tumors ◽

Cell Cycle Arrest ◽

Tumor Cells ◽

Methanol Extract ◽

Cycle Arrest ◽

Anticancer Effects ◽

Brain Tumor Cells

Glioblastoma multiforme (GBM) is a highly vascularized and invasive neoplasm. The methanol extract ofAngelica sinensis(AS-M) is commonly used in traditional Chinese medicine to treat several diseases, such as gastric mucosal damage, hepatic injury, menopausal symptoms, and chronic glomerulonephritis. AS-M also displays potency in suppressing the growth of malignant brain tumor cells. The growth suppression of malignant brain tumor cells by AS-M results from cell cycle arrest and apoptosis. AS-M upregulates expression of cyclin kinase inhibitors, including p16, to decrease the phosphorylation of Rb proteins, resulting in arrest at the G0-G1phase. The expression of the p53 protein is increased by AS-M and correlates with activation of apoptosis-associated proteins. Therefore, the apoptosis of cancer cells induced by AS-M may be triggered through the p53 pathway. Inin vivostudies, AS-M not only suppresses the growth of human malignant brain tumors but also significantly prolongs patient survival. In addition, AS-M has potent anticancer effects involving cell cycle arrest, apoptosis, and antiangiogenesis. Thein vitroandin vivoanticancer effects of AS-M indicate that this extract warrants further investigation and potential development as a new antibrain tumor agent, providing new hope for the chemotherapy of malignant brain cancer.

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PS2 - 171 Bmi1 Identifies Treatment-Refractory Stem Cells in Human Glioblastoma

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques ◽

10.1017/cjn.2016.366 ◽

2016 ◽

Vol 43 (S4) ◽

pp. S13-S13

Author(s):

P. Vora ◽

M. Qazi ◽

C. Venugopal ◽

M. Subapanditha ◽

S. Mahendram ◽

...

Keyword(s):

Stem Cell ◽

Brain Tumor ◽

High Throughput Sequencing ◽

Critical Role ◽

Treatment Protocol ◽

Tumor Formation ◽

Self Renewal ◽

Tumor Relapse ◽

Treatment Refractory

Glioblastoma (GBM) is an aggressive brain tumor that is resistant to conventional radiation and cytotoxic chemotherapies. We hypothesize that brain tumor initiating cells (BTICs), a subpopulation of treatment-resistant cells with stem cell properties cause tumor relapse and a subset of neural stem cell genes regulate BTIC self-renewal, driving GBM recurrence. We adapted the existing treatment protocol for adults with primary GBM for in vivo treatment of immunocompromised mice engrafted with GBMs. Post-chemoradiotherapy, the recovered GFP+GBMs were profiled for self-renewal and expression of critical stem cell genes. Using invitro and invivo gain-of-function/loss-of-function experiments, we investigated the regulatory functions of Bmi1 in primary neural stem & progenitor cells (NSPCs) and GBM tumor formation. Finally, global RNA-Seq profiling was performed to understand the consequences of Bmi1 dysregulation on target gene expression. GBM cells showed an increase in Bmi1 levels post-chemoradiotherapy, suggesting the presence of a treatment-refractory BTICs. GFP+cells extracted from treated xenografts had higher self-renewal and BTIC marker expression. Although treated mice responded to therapy, we observed tumor relapse with increased Bmi1 expression. Knockdown of Bmi1 diminished self-renewal and proliferation of GBM cells and delayed tumorigenesis, highlighting a critical role for Bmi1 in tumor maintenance. Conversely, over-expressing Bmi1 in NSPCs failed to initiate tumor formation in vivo. Using high-throughput sequencing data, we generated a map of signaling pathways dysregulated in GBM that may lead to tumor recurrence. Our data confirms the existence of a rare treatment-refractory BTIC population with enhanced self-renewal capacity that escapes therapy and drives tumor relapse.

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TMOD-30. IDENTIFYING NEW DRIVERS OF GROUP 3 MEDULLOBLASTOMA

Neuro-Oncology ◽

10.1093/neuonc/noaa215.980 ◽

2020 ◽

Vol 22 (Supplement_2) ◽

pp. ii234-ii234

Author(s):

Meher Beigi Masihi ◽

Catherine Lee ◽

Alexandra Garancher ◽

Grace Furnari ◽

Robert Wechsler-Reya

Keyword(s):

Brain Tumor ◽

Molecular Mechanisms ◽

Expression Profiles ◽

Gene Expression Profiles ◽

Pediatric Brain Tumor ◽

Genetic Alterations ◽

Sleeping Beauty ◽

Tumor Formation ◽

Group 3

Abstract Medulloblastoma (MB) is the most common malignant childhood brain tumor. MB can be divided into four major subgroups – WNT, Sonic hedgehog (SHH), Group 3 (G3-MB), and Group 4 (G4-MB) – that exhibit distinct genetic alterations, gene expression profiles, and clinical outcomes. Patients with G3-MB have the worst prognosis, and a deeper understanding of this form of the disease is critical for development of new therapies. Most G3-MBs express high levels of the MYC oncogene, suggesting that MYC plays an important role in tumorigenesis. However, MYC overexpression is not sufficient to drive tumor formation. To identify genes that cooperate with MYC to promote development of G3-MB, we performed an in vivo mutagenesis screen using mice expressing the Sleeping Beauty (SB) transposon. Cerebellar stem cells isolated from transposon/transposase-expressing transgenic mice were infected with viruses encoding Myc, and these cells were transplanted into the cerebellum of adult hosts. Tumors that arose were subjected to DNA and RNA sequencing to identify candidate genes, and these genes were subjected to functional analysis to determine whether they could cooperate with Myc to drive G3-MB. These studies identified the transcription factor Ras-responsive element binding protein 1 (Rreb1) as a potent Myc-cooperating gene. Tumors driven by Myc and Rreb1 (MR tumors) resemble G3-MB at a histological and molecular level. Moreover, RREB1 is overexpressed in human G3-MB, and knockdown of RREB1 expression impairs growth of G3-MB cell lines and patient-derived xenografts. Ongoing studies are aimed at identifying the molecular mechanisms by which Rreb1 contributes to tumor growth. Our studies demonstrate an important role for RREB1 in G3-MB, and provide a new model that can be used to identify therapeutic targets and develop more effective and less toxic therapies for this devastating pediatric brain tumor.

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In Vivo Generation of Neural Tumors from Neoplastic Pluripotent Stem Cells Models Early Human Pediatric Brain Tumor Formation

Stem Cells ◽

10.1002/stem.1017 ◽

2012 ◽

Vol 30 (3) ◽

pp. 392-404 ◽

Cited By ~ 22

Author(s):

Tamra E. Werbowetski-Ogilvie ◽

Ludivine Coudière Morrison ◽

Aline Fiebig-Comyn ◽

Mickie Bhatia

Keyword(s):

Stem Cells ◽

Brain Tumor ◽

Pluripotent Stem Cells ◽

Pediatric Brain Tumor ◽

Tumor Formation ◽

Pediatric Brain ◽

Early Human

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JNK1 phosphorylation of SCG10 determines microtubule dynamics and axodendritic length

The Journal of Cell Biology ◽

10.1083/jcb.200511055 ◽

2006 ◽

Vol 173 (2) ◽

pp. 265-277 ◽

Cited By ~ 122

Author(s):

Tatsiana Tararuk ◽

Nina Östman ◽

Wenrui Li ◽

Benny Björkblom ◽

Artur Padzik ◽

...

Keyword(s):

Brain Development ◽

Cell Movement ◽

Brain Regions ◽

Microtubule Dynamics ◽

Embryonic Brain ◽

Interacting Proteins ◽

Neurite Elongation ◽

And Migration

c-Jun NH2-terminal kinases (JNKs) are essential during brain development, when they regulate morphogenic changes involving cell movement and migration. In the adult, JNK determines neuronal cytoarchitecture. To help uncover the molecular effectors for JNKs in these events, we affinity purified JNK-interacting proteins from brain. This revealed that the stathmin family microtubule-destabilizing proteins SCG10, SCLIP, RB3, and RB3′ interact tightly with JNK. Furthermore, SCG10 is also phosphorylated by JNK in vivo on sites that regulate its microtubule depolymerizing activity, serines 62 and 73. SCG10-S73 phosphorylation is significantly decreased in JNK1−/− cortex, indicating that JNK1 phosphorylates SCG10 in developing forebrain. JNK phosphorylation of SCG10 determines axodendritic length in cerebrocortical cultures, and JNK site–phosphorylated SCG10 colocalizes with active JNK in embryonic brain regions undergoing neurite elongation and migration. We demonstrate that inhibition of cytoplasmic JNK and expression of SCG10-62A/73A both inhibited fluorescent tubulin recovery after photobleaching. These data suggest that JNK1 is responsible for regulation of SCG10 depolymerizing activity and neurite elongation during brain development.

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