bluuebunny/crossref_metadata_2025_split huggingface dataset:
STEM-03. WAVE1 KNOCKDOWN ENHANCES THE ANTITUMOR EFFICACY IN PRIMARY GLIOBLASTOMA NEUROSPHERES
Authors: Namagiri Sriya , Thammegowda Shilpa , Sur Hannah , Vézina Amélie , Chowdhury Ashis , Maric Dragan , Gangaplara Arunakumar , Edwards Nancy , Jackson Sadhana , Ray-Chaudhury Abhik , Heiss John , Banasavadi-Siddegowda Yeshavanth Kumar 
Published: December 2020

Abstract

INTRODUCTION
Despite multi-model therapies that include maximal surgical resection, radiation, chemotherapy, and tumor treating fields, the median survival of Glioblastoma (GBM) patients is around 15 months. WASP-family verprolin homologous protein 1 (WAVE1) is a downstream effector that receives signals from small GTPases to regulate the actin cytoskeleton. WAVE1’s interaction with arp2/3 modulates critical roles, such as cell motility and morphologic changes. Expression of WAVE1 has been implicated in leukemia, ovarian, and prostate cancer. In this study, we tested the role of WAVE1 in GBM tumor biology.

METHODS
Expression of WAVE1 in normal brain and GBM tumor specimens was assessed by immunohistochemistry (IHC). The relevance of targeting WAVE1 for GBM therapy was evaluated in vitro by western blot, proliferation assay, cell cycle analysis, apoptosis assay, migration assay, and neurosphere formation assay using scrambled and target specific WAVE1-siRNA in patient-derived primary GBM neurospheres (GBMNS).

RESULTS
IHC data shows that the expression of WAVE1 is higher in GBM tumor samples than in low-grade gliomas and normal brain tissues. WAVE1 expression is upregulated in GBMNS compared to normal human astrocytes. WAVE1 knockdown significantly decreased the proliferation, migration, and self-renewal of GBMNS without affecting its cell cycle progression. Furthermore, WAVE1 depletion did not show any alterations in the apoptotic cell population, indicating that WAVE1 knockdown has a cytostatic effect on GBMNS.

CONCLUSION
Expression of WAVE1 positively correlates with GBM, and its knockdown imparts antitumor efficacy through cytostasis.
STEM-05. SINGLE CELL SEQUENCING CHARACTERIZES SPATIAL AND TEMPORAL RELATIONSHIPS OF ENHANCING AND NON-ENHANCING REGIONS IN HIGH-GRADE GLIOMA
Authors: Patel Kunal , Kawaguchi Riki , Alvarado Alvaro , Muthukrishnan Deepthi , Everson Richard , Liau Linda , Geschwind Daniel , Ellingson Benjamin , Kornblum Harley 
Published: December 2020

Abstract

INTRODUCTION
Treatments of high grade glioma focus on the contrast enhancing (CE) portion of the tumor. However, given the invasive nature of glioma, residual tumor cells responsible for recurrence likely exist in the non-enhancing (NE) region.

METHODS
In 3 patients undergoing surgery for malignant glioma, we used pre-operative magnetic resonance images to prospectively identify biopsy targets in the CE region and locations 0.5-2.0cm beyond the CE edge. We carried out single cell sequencing on image guided biopsy specimens to generate 12,528 RNA profiles.

RESULTS
In all samples, tumor cells clustered into three predominant groups: tumor cells with astrocyte markers (ASC-like), tumor cells with oligodendrocyte markers (ODC-like), and tumor cells with neither marker. This last group consisted of a small proportion of tumor cells and expressed putative stem cell markers (PROM1, NES, SLC1A3, A2B5, ID1). A trajectory analysis consistently positioned this group as branching off into either ASC-like or ODC-like cells. CE regions had different cellular compositions than NE regions, with higher proportions of tumor, endothelial cells, T-cells, and NK cells. Using location and cell density data, we modeled expected tumor burden, predicting tumor cells up to 1.5cm beyond the CE region of the tumor. There were significant differences in gene expression between CE and NE tumor cells, with increased inflammation and hypoxia in the CE region versus increased proliferative markers in the NE region. Tumor cells in the NE region were characterized by increased proliferation, markers of invasion, and markers of self-renewal.

CONCLUSIONS
Single cell sequencing illustrates multiple glioma cell types and suggests a hierarchical relationship between tumor cell types. CE and NE regions exhibit different tumor and non-tumor cell populations as well as different gene expression profiles within individual cell types. There remains a significant tumor cell burden in the NE portion of tumor, including actively proliferating cells.
STEM-10. LONG-LASTING TUMOR TREATING FIELDS (TTFIELDS) STIMULATION OF GLIOBLASTOMA PRIMARY CULTURE DAMAGES PREFERENTIALLY FULLY DIFFERENTIATED CANCER CELLS
Authors: Castiglione Stefania , Ranucci Matteo , Cannavale Gaetano , Cianci Francesca , Verduci Ivan , Mazzanti Michele 
Published: December 2020

Abstract
Glioblastoma (GBM) is the most aggressive among brain tumors. Radiotherapy and chemotherapy as adjuvant procedures after surgical removal of the tumor mass, are often accompanied by undesirable symptoms and result in an extremely poor prognosis. In the last twenty years, it has been demonstrated that the only treatment able to improve the life expectancy of patients with GBM has been Tumor Treating Fields (TTFields) application. However, despite different therapeutic actions, tumor relapse occurs inexorably in most of the patients. There is scientific consensus that tumor recurrence is due to a population of cells named GBM stem cells (GSCs). GSCs represent a restricted subpopulation in the tumor mass, which is mainly composed of bulk cells. The main characteristic of GSCs is their tumorigenic potential even if a small number of cells are left after surgery. Our working hypothesis is based on the evidence that TTFields destabilize the mitotic spindle of dividing cells. Thus, TTFields stimulation should preferentially target bulk cells because of their higher proliferation rate compared to GSCs. Preliminary experiments performed using GBM primary cultures obtained from patients’ biopsies confirmed the presence of two different cell populations. In GBM, primary cultures maintained in stem-cell permissive medium, more than 70% of cells do not show stemness properties. After 72 hours of TTFields stimulation, almost 50% of the cells die. The remaining cells were more than 50% positive for CD44, SOX2, OCT4, and Nanog stemness markers, suggesting an enrichment of GSCs within the population. Following long lasting stimulation (up to 288 hours), GSCs percentage further increased and, more importantly, cells restored their ability to proliferate. In conclusion, TTFields treatment demonstrated efficacy by delaying GBM expansion. However, to prevent GBM relapse, it is imperative to increase the inhibitory efficiency of TTFields, specifically on GBM stem cell growth.
STEM-13. FUNCTIONAL CHARACTERIZATION OF THE ZFHX4-CHD4 INTERACTION IN GLIOBLASTOMA CANCER STEM CELLS
Authors: Galdieri Luciano , Grinwald Mitchell , Gugala Zibi , Oates Edward , Chheda Milan 
Published: December 2020

Abstract
Glioblastoma stem cells (GSCs) they may be one reason for inevitable recurrence of GBM. We previously discovered that Zinc Finger Homeobox 4 (ZFHX4), a 450kD transcription factor, is required to maintain the GSC state. ZFHX4 interacts with CHD4, a core member of the nucleosome remodeling and deacetylase (NuRD) complex, which activates or represses gene expression via two distinct functions - histone deacetylation and ATP-dependent chromatin remodeling. CHD4 suppression phenocopies ZFHX4 suppression. The precise nature and function of the ZFHX4 interaction with CHD4 is not understood. Here we report that the ZFHX4-CHD4 interaction requires a single zinc-finger domain. An incremental truncation screen revealed that ZFHX4 amino acids 1838 to 2387, which contains zinc fingers 14 and 15, are required to bind CHD4. Disrupting the zinc coordination of zinc finger 14 impaired the ZFHX4-CHD4 interaction. Moreover, by overexpressing ZFHX4 amino acids 1838 to 2487, we decreased CHD4 recruitment to transcription regulatory regions of the stem cell genes SOX2 and SOX9, decreased transcription, and reduced clonogenic self-renewal. These results may provide the structural basis for new treatments to target GSCs and prevent recurrence in this devastating disease.
STEM-15. SMALL BUT FIERCE: THE ROLE OF EXTRACELLULAR VESICLES IN MESENCHYMAL TRANSITION AND THERAPEUTIC RESISTANCE IN GLIOBLASTOMA
Authors: Schweiger Markus , Li Mao , Fleming Renata , Tabet Elie , Würdinger Thomas , Tannous Bakhos 
Published: December 2020

Abstract
Glioblastoma (GBM) is a dismal disease and despite optimal treatment, long-term survival remains uncommon. Molecular classification revealed three distinct GBM subgroups and has helped to shine light on the tumor’s inter/intratumoral heterogeneity. Interestingly, recent evidence shows plasticity between these subtypes in which the proneural (PN) glioma stem-like cells undergo transition into the more aggressive mesenchymal (MES) subtype leading to therapeutic resistance. Extracellular vesicles (EVs) are considered a heterogeneous group of membrane-limited vesicles secreted by nearly every cell. In the context of GBM, these biological nanoparticles act as multifunctional signaling complexes and play an important role in intercellular communication allowing cancer cells to exchange information with each other, the tumor microenvironment, and distant cells. We show that MES cells derived EVs modulate PN cells to increase migratory potential, stemness, invasiveness, aggressiveness, and therapeutic resistance by inducing mesenchymal transition through NF-KB/STAT3 signaling. Furthermore, we shine light on the role of EVs derived from irradiated GBM cells and their potential impact on microglia and resulting treatment resistance.
STEM-21. CLINICAL RELEVANCE OF CANCER STEM CELL CYTOTOXICITY ASSAY IN GUIDING TREATMENT FOR GLIOBLASTOMA
Authors: Pier Paolo Claudio , Ranjan Tulika , Howard Candace , Yu Alexander , Xu Linda , Aziz Khaled , Jho David , Leonardo Jodi , Denning Krista , Valluri Jagan 
Published: December 2020

Abstract
BACKGROUND. The prognosis of glioblastoma (GBM) treated with standard-of-care regimens remains very poor with a median time to recurrence of 7-9 months, and a median survival of 15-18 months. GBMs contain a small, but resilient population of cancer stem cells (CSCs) that contribute to tumor initiation, maintenance, and therapy resistance. For these reasons, its is extremely important to determine the sensitivity of CSCs to chemotherapeutic agents, with the intent of identifying more effective treatment protocols which would then translate into improved clinical survival. METHODS. We have used a novel CLIA and CAP-accredited Cancer Stem Cell Cytotoxicity Assay (ChemoID) to guide treatment for 55 Grade III and Grade IV glioma patients with the most efficacious chemotherapy treatments from a panel of FDA approved drugs or their combinations. Patients were evaluated by MRI scans and response was assessed according to RANO criteria. RESULTS: We report here a prospective clinical investigation using the ChemoID assay to measure the sensitivity and resistance of CSCs and bulk of tumor cells cultured from 55 GBM clinical specimens challenged with several chemotherapy agents, which were also correlated to the clinical response of the treated patients, independently of other biomarkers. The median recurrence time was 15 months for patients with a sensitive (&gt;40% cell kill) CSCs test versus only 6 months for patients with a resistant CSCs test. CONCLUSIONS. The data suggests that GBM patients treated with CSC Cytotoxicity Assay-guided responsive drugs have delayed time to recurrence and the assay has the potential to help tailor chemotherapy choices to improve clinical outcomes.
STEM-23. INHIBITING PROTEIN PHOSPHATASE 2A INCREASES THE ANTITUMOR EFFECT OF PROTEIN ARGININE METHYLTRANSFERASE 5 INHIBITION IN MODELS OF GLIOBLASTOMA
Authors: Kumar Banasavadi Siddegowda Yeshavanth , Sur Hannah , Otani Yoshihiro , Rachaiah Guruprasad , Namagiri Sriya , Chowdhury Ashis , Lewis Cole , Shimizu Toshihiko , Gangaplara Arunakumar , Wang Xiang , Vézina Amélie , Maric Dragan , Jackson Sadhana , Yan Yuanqing , Zhengping Zhuang , Ray-Chaudhury Abhik , Kumar Sachin , Chittiboina Prashant , Heiss John , Yoo Ji Young , Kaur Balveen 
Published: December 2020

Abstract
BACKGROUND: Despite multi-model therapy of maximal surgical resection, radiation, chemotherapy, and tumor treating fields, median survival of Glioblastoma (GBM) patients is less than two years. Protein Arginine Methyltransferase 5 (PRMT5) catalyzes the symmetric di-methylation of arginine residues and is overexpressed in GBM. Inhibition of PRMT5 causes senescence of immature GBM tumor cells. LB100, first-in-class small molecule inhibitor of Protein Phosphatase 2A (PP2A) can sensitize therapy-resistant tumor cells. Here, we tested the anti-GBM effect of concurrent PRMT5 and PP2A inhibition. Methods: Patient-derived primary GBM neurospheres (GBMNS), transfected with PRMT5 target-specific siRNA were treated with LB100 and subjected to in vitro assays including PP2A activity and western blot. The intracranial mouse xenograft model was used to test the in vivo antitumor efficacy of combination treatment. Results: We found that PRMT5-depletion increased PP2A activity in GBMNS. LB100 treatment significantly reduced the viability of PRMT5-depleted GBMNS compared to PRMT5 intact GBMNS. LB100 enhanced the G1 cell cycle arrest induced by PRMT5-depletion. Combination therapy also increased the expression of phospho-MLKL. Necrostatin-1 rescued PRMT5-depleted cells from the cytotoxic effects of LB100, indicating that necroptosis caused the enhanced cytotoxicity of combination therapy. In the in vivo mouse tumor xenograft model, LB100 treatment combined with transient depletion of PRMT5 significantly decreased tumor size and prolonged mice survival, while LB100 treatment alone had no survival benefit. Conclusion: Overall, combined PRMT5 and PP2A inhibition had significantly greater antitumor effects than PRMT5 inhibition alone.
STEM-28. NANOPARTICLES ENCAPSULATING A CONNEXIN43 MIMETIC PEPTIDE LIMIT GLIOMA STEM CELL SURVIVAL AND GLIOBLASTOMA PROGRESSION
Authors: Will John , Thompson Emily , Harrigan Megan , Smyth James , Sheng Zhi , Gourdie Robert , Sontheimer Harry , Foster Johan , Lamouille Samy 
Published: December 2020

Abstract
Glioblastoma (GBM) is the most common and aggressive primary adult brain tumor in the US. The current treatment regimen for GBM still retains an alarmingly poor prognosis, with median survival of only 14.6 months. Failure to generate more effective treatment strategies is due to the infiltrative nature of GBM tumor cells, which hinders complete surgical resection, and cellular heterogeneity within GBM tumors, with a sub-population of glioma stem cells (GSCs) resistant to irradiation treatment and chemotherapeutic agents including temozolomide. As a result, all treated GBM patients will experience tumor recurrence, highlighting the need for novel approaches in targeting such refractory tumor cell populations to successfully treat GBM tumors and prevent recurrence. Using super resolution localization microscopy, we have identified that increased interaction of connexin43 (Cx43) with microtubules in GSCs confers tumorigenic behavior to these cells. We employed a Cx43 mimetic peptide named JM2 (juxtamembrane 2) that encompasses the microtubule binding sequence of the Cx43 carboxy-terminus. This peptide drug efficiently and specifically disrupts the interaction of Cx43 with microtubules and limits GSC survival, proliferation, and migration, without affecting normal human astrocytes. Next, we implemented the therapeutic strategy of JM2 encapsulation within biodegradable polymeric nanoparticles (NPs) to reduce administration frequency and patient discomfort, and increase peptide stability and activity. We confirmed sustained release of JM2 from these poly(lactic-co-glycolic) acid biodegradable NPs, and JM2 bioactivity through disruption of Cx43 interaction with microtubules. Administration of JM2-NPs inhibits GSC-derived neurosphere formation in vitro and patient GBM-derived organoid growth ex vivo. Finally, using an orthotopic xenograft brain tumor mouse model, we demonstrate in vivo that JM2-NPs significantly decrease the number of GSCs within brain tumors, and inhibit the formation of highly invasive GBM tumors. Our findings on generation of JM2-NPs to target GSC survival lays the foundation for future clinical trials in newly diagnosed GBM patients.
STEM-30. NECROPTOTIC ASTROCYTES CONTRIBUTE TO MAINTAINING STEMNESS OF DISSEMINATED MEDULLOBLASTOMA THROUGH CCL2 SECRETION
Authors: Liu Hailong , Sun Youliang , Franco-Barraza Janusz , Wang Z John , Yu Xinguang , Feng Shiyu 
Published: December 2020

Abstract
Medulloblastoma (MB) with metastases at diagnosis and recurrence correlates with poor prognosis. Unfortunately, the molecular mechanism underlying metastases growth has received less attention than primary therapy-naïve MB. Though astrocytes have been frequently detected in brain tumors, their roles in regulating the stemness properties of MB stem-like cells (MBSCs) in disseminated lesions remain elusive. Effects of tumor-associated astrocytes (TAA)-secreted CCL2 on MBSCs self-renewal was determined by immunostaining analysis. Necroptosis of TAA was examined by measuring necrosome activity. Alterations in Notch signaling were examined after inhibition of CCL2. Progression of MBSCs-derived tumors was evaluated after pharmaceutical blockage of necroptosis. TAA, as the essential components of disseminated tumor, produced high level of CCL2 to shape inflammation microenvironment, which stimulated the enrichment of MBSCs in disseminated MB. In particular, CCL2 played a pivotal role in maintaining stem-like properties via JAK2/STAT3 mediated activation of Notch signaling. Loss of CCL2/CCR2 function repressed JAK2/STAT3-Notch pathway and impaired MBSCs proliferation, leading to a dramatic reduction of stemness, tumorigenicity and metastasizing capability. Furthermore, necroptosis-induced CCL2 release depended on RIP1/RIP3/MLKL activation in TAA, which promoted the oncogenic phenotype. Blockade of necroptosis resulted in CCL2 deprivation and compromised MBSCs self-proliferation, indicating MBSCs outsourced CCL2 from necroptotic TAA. Finally, CCL2 was upregulated in high-risk stages of MB, further supporting its value as a prognostic indicator. These findings highlighted the critical role of CCL2/CCR2 in Notch signaling activation in MBSCs, and revealed a necroptosis-associated glial cytokine microenvironment driving stemness maintenance in disseminations.
SURG-07. DETECTION OF GLIOMA INFILTRATION AT THE TUMOR MARGIN USING QUANTITATIVE STIMULATED RAMAN SCATTERING MICROSCOPY
Authors: Pekmezci Melike , Morshed Ramin , Chunduru Pranathi , Pandian Balaji , Young Jacob , Villanueva-Meyer Javier , Tihan Tarik , Sloan Emily , Aghi Manish , Molinaro Annette , Berger Mitchel , Hervey-Jumper Shawn 
Published: December 2020

Abstract

BACKGROUND
Differentiating neoplastic tumor tissues from normal brain at the infiltrative tumor margin remains challenging. Stimulated Raman scattering microscopy (SRM) is a rapid, label-free technique that provides microscopic imaging of unprocessed tissues. However, it has never been studied as a tool to enhance extent of resection.

METHODS
In this single center study, patients with WHO II-IV gliomas undergoing surgical resection were included. Margin samples were taken with corresponding stereotactic coordinates. Each tumor margin sample was analyzed using (1) H&E, (2) SRM, and (3) immunohistochemical (IHC) stains for IDH1-R132H or p53. Specimens were imaged fresh with SRM, inked for orientation and placed in formalin for routine processing. Stained slides were scored by 3-neuro-pathologists using a semiquantitative 2-tiered scoring system for the presence or absence of residual tumor. SRM microscopy images were segmented into cellularity. The intraobserver measure of agreement between modalities for each pathologist was calculated using Cohen’s kappa.

RESULTS
A total of 31 patients and 179 margin specimens were acquired. Postoperative MRI confirmed that 169 (94%) of glioma margin sample coordinates were indeed at the tumor margins (10 of 179 were not true margins). All 10 samples which were not true margins were identified as having residual tumor by SRM. IHC semiquantitative scoring of margin specimen confirmed 72 of 128 samples (56%) had residual tumor. Similarly, H&E-scoring confirmed 82 of 169 samples (49%) and 82 of 167 samples (49%) by SRM-scoring had residual tumor. Intraobserver agreements between all 3 modalities confirmed agreement: IHC-SRM was near perfect (K-0.84, CI-0.750-0.94); IHC-H&E substantial, (K-0.67 CI-0.54-0.80); SRM-H&E agreement substantial (K-0.72 CI-0.62-0.83). Margin samples with residual tumor demonstrated higher tissue cellularity when compared with samples without tumor (p&lt; 0.0001).

CONCLUSIONS
SRM allows for identification of residual microscopic disease at the infiltrative tumor margin and therefore may be a promising tool to enhance extent of resection.
SURG-08. AWAKE CRANIOTOMY WITH BRAIN MAPPING FOR DIFFUSE LOW-GRADE GLIOMA: CASE REPORT OF INSTITUTIONAL EXPERIENCE IN OVERCOMING HURDLES IN A LOW-RESOURCE SETTING
Authors: Manigos Kirby , Ferraris Kevin Paul , Navarro Joseph Erroll , Seng Kenny , Alcazaren Jose Carlos 
Published: December 2020

Abstract
Maximal safe resection of low-grade gliomas located in functional areas of the cortex while avoiding postsurgical neurologic deficits can be achieved by awake craniotomy with brain mapping. The effectiveness of this surgical technique is fairly established in the developed world, however it remains to be routinely applied in low-middle income countries due to limited resources and lack of equipment. We present the case of a 44 year-old, right-handed male who had a 2-year history of focal aware motor seizures but was otherwise neurologically intact. Neuropsychological testing revealed no cognitive impairment. Cranial magnetic resonance imaging (MRI) revealed a non-enhancing, ill-defined tumor centered on the left insula and extending into the frontotemporal opercula, corona radiata, and posterior limb of the internal capsule—hypointense by T1-weighted sequence and hyperintense by T2-weighted sequence, thus radiographically consistent with diffuse low-grade glioma. Blood-oxygen-level-dependent functional MRI revealed left hemispheric language dominance in the cortex overlying the tumor, but with no motor cortex involvement. The patient underwent a protocol-driven awake craniotomy, intraoperative positive brain mapping using standard cortical stimulator, transsylvian and transcortical transopercular microsurgical approaches to achieve greater than 80% excision of the tumor. Postoperatively, the patient was seizure-free and with similar neurocognitive status prior to the surgery. The patient had been following up for standard adjuvant chemotherapy and radiotherapy. Avoidance of postsurgical neurologic deficits and maximal cytoreduction can still be achieved by awake craniotomy with brain mapping in settings with limited resources. Despite the lack of other perioperative tools and adjuncts such as diffusion tensor imaging, intraoperative ultrasonography, and even intraoperative MRI that are routinely available in high-resource settings, we illustrate in this case that comparable outcomes could be achieved by overcoming hurdles and aiming for the asymptote to the up-to-date and ideal neurosurgical treatment for diffuse low-grade gliomas.