bluuebunny/crossref_metadata_2025_split huggingface dataset:
DDEL-13. CILIA INHIBITORS SYNERGIZE WITH TEMOZOLOMIDE TO DRAMATICALLY IMPROVE SURVIVAL IN ORTHOTOPIC MURINE MODELS OF GLIOBLASTOMA
Authors: Umlauf Benjamin 
Published: November 2023

Abstract
Patients with malignant brain tumors such as glioblastoma face a poor prognosis with a median survival of less than two years. Recent glymphatic studies demonstrate the interconnectivity between the fluid in the brain parenchymal and ventricular spaces. We reasoned enhancing the accumulation of a drug in the cerebral spinal fluid (CSF) of the ventricular space will also enhance the accumulation of the drug in the parenchyma where a GBM resides. To improve drug accumulation in the CSF, we modulated the motility of ependymal cell cilia. Ependymal cells coat the ventricles and display motile cilia that mechanically propel CSF through the ventricular space. Impairing ciliary motion could slow down CSF turnover without affecting the overall amount of CSF in the brain and central nervous system. To test these hypotheses, we identified FDA-approved therapeutics that are known to impair airway cilia as a “side effect.” Seven candidate drugs were administered into the ventricle of mice bearing orthotopic GBM in combination with systemic temozolomide. Five of the seven cilia-inhibiting drugs significantly improved overall survival when combined with temozolomide compared to controls. The lead candidate, lidocaine, demonstrated a synergistic relationship with temozolomide, and 100% of animals treated with the combination survived to the study endpoint tumor free. We demonstrate lidocaine can impair cilia motility in vitro and in vivo. Combining intraventricular lidocaine with temozolomide is well tolerated and results in a 2.8-fold increase in brain temozolomide concentration per dose compared to controls. Finally, we validate these data in two human PDX orthotopic xenograft GBM murine models, including an un-methylated MGMT GBM that became sensitive to temozolomide with the combination treatment. These studies offer a new concept for treating malignant brain tumors and potentially a scheme to improve the treatment of additional encephalopathies in the future.
DDDR-01. P38-MAPK INHIBITOR REVERSED CISPLATIN RESISTANCE IN NON-SMALL CELL LUNG CANCER BRAIN METASTASES BY REGULATING P-GP AND BCRP OF BLOOD-TUMOR BARRIER
Authors: Liang Lun , Yu Min , Yang Shilun , Duan Hao , He Zhenqiang , Wang Zhenning , Chang Junlei , Mou Yonggao 
Published: November 2023

Abstract

BACKGROUND
Previous studies have shown that the blood-brain barrier (BBB) of brain metastases (BMs) is destroyed, and the neovascularization and tumor cells constitute the blood-tumor barrier (BTB). Whether the BTB plays a role in the chemotherapy resistance of BMs is lacking in-depth research. This study aims to elucidate the possible role of BTB in cisplatin resistance of BMs from non-small cell lung cancer (NSCLC).

METHODS
AND MATERIALS; A multicenter retrospective cohort study including 1177 patients with NSCLC-BMs was conducted to explore the prognosis. Immunohistochemistry and immunofluorescence staining were used to verify the expression of some BBB markers in the BTB. Animal models of BMs were constructed by cardiac injection of A549. NSCLC-BMs cell lines A549-mBrain were selected in vivo. Cisplatin susceptibility tests and CCK8 proliferation tests were performed on A549-mBrain. RNA sequencing, Western Blot and qPCR were used to explore the mechanism that might regulate cisplatin resistance in A549-mBrain.

RESULTS
Platinum-based chemotherapy did not improve the overall survival time of NSCLC-BMs. BTB in NSCLC-BMs lacked astrocytes and pericytes, but still expressed several molecular markers of BBB, such as tight junction, transcytosis, and efflux pump. The efflux pump P-gp and BCRP expressions were higher in NSCLC-BMs than those in the lung primary lesion by immunohistochemistry in patients' tumor section. The A549-mBrain showed cisplatin resistance compared with the parental A549. Besides, the expression of P-gp and BCRP were also higher in A549-mBrain than parental A549 by Western Blot and qPCR. In A549-mBrain, inhibition of the p38-MAPK signaling pathway decreased the expression of P-gp and BCRP, thus increasing the sensitivity to cisplatin.

CONCLUSION
BTB may retain some BBB function in NSCLC-BMs, in which efflux pump P-gp and BCRP expression were related to cisplatin resistance. p38-MAPK inhibitor reversed cisplatin resistance in NSCLC-BMs by regulating P-gp and BCRP.
DDDR-02. THE EFFICACY OF SOTORASIB IN KRAS-MUTATED NSCLC PATIENTS WITH BRAIN METASTASES: A RETROSPECTIVE COHORT STUDY
Authors: Lebouille-Veldman Anna , Taros Trent , Nawabi Noah , Peng Luke , Philips John 
Published: November 2023

Abstract

INTRODUCTION
Sotorasib has emerged as a favorable treatment option for patients with advanced KRAS-mutated non-small cell lung cancer (NSCLC) including those with brain metastases (BM). The objective of this study was to determine the efficacy of sotorasib in the treatment of pre-treated BMs in patients with NSCLC.

METHODS
This retrospective cohort study included adult patients with KRAS-mutated NSCLC with BMs who received sotorasib between April-2021 and March-2023 at Mass General Brigham Hospitals. Intracranial progression-free survival (ICPFS) and overall survival (OS) were the primary endpoints and were explored using Kaplan Meier analyses for three groups of patients: patients with active BMs and no local therapy (1), patients with active BMs with local treatment within one month of sotorasib initiation (2) and patients with radiographically stable BMs following previous local treatment (3).

RESULTS
31 patients with NSCLC and BMs were included (23% male). Mean age at start of sotorasib was 60. 87% of patients had primary lung adenocarcinoma, and 68% of patients had between 1 and 4 BMs when they started sotorasib. Differences in survival distributions for ICPFS for patients in each of the three groups were statistically significant, χ2(2) = 7.600, p = 0.022. Median ICPFS was 3 months (95% CI: 0 – 8.9) from start of sotorasib for group 1, 5 months (0-11.5) group 2, and 15 months (0-33.5) for group 3. Median OS was 4 months (0-8.8) for group 1, 6 months (0-13.7) for group 2, and 12 months (3.6-20.4) for group 3. 55% of patients experienced intracranial progression on sotorasib, including 39% of patients who had stable BMs at sotorasib initiation.

CONCLUSION
The results of this study indicate that while sotorasib does have intracranial activity, a multimodal approach to BM therapy is still warranted, as are future studies with larger patient samples, controls, and extended follow up.
DDDR-03. DRUG REPURPOSING VIA ULTRA-HIGH THROUGHPUT 3D SPHEROIDS SCREENING FOR HUMAN SCHWANNOMA
Authors: Lei Kecheng , Tora Muhibullah , Lakhina Yuliya , Zhang Michelle , Qui Min , Fu Haian , Du Yuhong , Boulis Nicholas 
Published: November 2023

Abstract
Schwannoma is the most common benign peripheral nerve tumor occurring sporadically or as part of neurofibromatosis syndromes. While surgical resection can be used as the primary treatment option for Schwannoma, patients could face life-long repeated surgeries due to recurrence of syndromes that decreases the quality of life. Thus, non-invasive treatments for Schwannoma are highly demanded. To discover novel therapeutics for non-invasive Schwannoma treatment, in this project, we leveraged the benefits of drug repurposing high-throughput screening (HTS) of FDA-approved drugs using 3D spheroids derived from Schwannoma patient samples. Both 2D primary cells and 3D primary spheroids models were developed from an IRB-approved tumor bank of schwannoma patient samples. The 3D spheroids were validated to recapitulate the features of patient tumors. We then conducted an ultra-HTS(uHTS) in 1536-well format of 2036 FDA-approved drugs on the growth and viability of Schwannoma patient-derived 3D spheroids. Seven FDA-approved drugs were identified from the pilot screen to inhibit the growth of Schwannoma patient-derived 3D spheroids. These drugs offer potential to serve as pharmacotherapeutics for Schwannoma non-invasive treatment. Our results have demonstrated the capability of a drug repurposing strategy for Schwannoma using uHTS and a patient-derived tumor bank. We further demonstrated that patient-derived drug sensitivity signatures could be encoded from the screening data to enable clustering of patients, which accounts for heterogeneity in Schwannoma and avoids "one-size-fits-all" solutions in future non-invasive Schwannoma treatment studies.
DDDR-04. TRANSIENT SUPPRESSION OF XPO1 ACTIVITY IS SUFFICIENT FOR SELINEXOR-INDUCED CYTOTOXICITY IN GLIOBLASTOMA CELLS LINES
Authors: Tang Yongjian , Sprinzen Lisa , Terada Yukinori , Pieper Russell 
Published: November 2023

Abstract
Inhibitors of the nuclear export protein exportin 1 (XPO1i) show promise in the treatment of leukemias and solid tumors, including brain tumors. XPO1i such as Selinexor reversibly bind and inhibit XPO1 activity, resulting in a lethal nuclear accumulation of a variety of XPO1 substrates. Although XPO1i activity has been suggested to require prolonged suppression of XPO1 activity, this point has not been directly addressed. To do so we generated glioblastoma and patient-derived glioblastoma xenograft cells that express either endogenous wild-type (WT) XPO1 or endogenous WT XPO1 plus a doxycycline-inducible point-mutant form of XPO1 (C528S) that exhibits full XPO1 activity but cannot bind or be inhibited by Selinexor. These cells were then incubated with doxycycline before, or at various time after, the initiation of continuous Selinexor exposure, after which the ability of C528S XPO1 to rescue cells from Selinexor-induced toxicity could be determined. All four glioblastoma cell lines examined were drug-sensitive (IC50 &lt; 600nM) and exhibited a dose-dependent nuclear retention of the XPO1 substrate RanBP1 following Selinexor exposure. Induced expression of C528S led to a doubling of XPO1 protein levels (WT plus C528S), and variable increases in Selinexor IC50, from 3-fold in GBM43 cells to 12,000-fold in LN229 cells. While induction of C528S expression prior to, or up to 8 h after, Selinexor exposure completely prevented Selinexor-induced cytotoxicity, cells could not be rescued after a 24 hr Selinexor exposure. Furthermore, the resistance provided by prolonged expression of C528S, or by shRNA-mediated suppression of XPO1 levels, was nearly 10-fold less than that provided by complete CRISPR-based replacement of WT XPO1 with C528S. These results therefore show that a transient suppression of XPO1 activity is sufficient for Selinexor-induced cytotoxicity in glioblastoma cells, and suggest that the Selinexor-induced lethality results from a combination of loss of XPO1 activity and Selinexor-XPO1 complex formation.
DDDR-05. TARGETED INHIBITION OF DNA REPAIR AND SURVIVAL SIGNALING IN DIFFUSE INTRINSIC PONTINE GLIOMAS
Authors: Barravecchia Ivana , Sharma Monika , Teis Robert , Cruz Jeanette , Mumby Rachel , Ziemke Elizabeth , Espinoza Carlos , Krishnamoorthy Varunkumar , Magnuson Brian , Ljungman Mats , Koschmann Carl , Whitehead Christopher , Sebolt-Leopold Judith , Galban Stefanie 
Published: November 2023

Abstract
Therapeutic resistance remains a major obstacle to successful clinical management of Diffuse Intrinsic Pontine Glioma (DIPG), a high-grade pediatric tumor of the brain stem. In nearly all patients, available therapies fail to prevent progression. Innovative combinatorial therapies that penetrate the blood-brain barrier and lead to long-term control of tumor growth are desperately needed. We identified mechanisms of resistance to radiotherapy, the standard of care for DIPG. Based on these findings, we rationally designed a brain-penetrant small molecule, MTX-241F, that is a highly selective inhibitor of EGFR and PI3 kinase family members, including the DNA repair protein DNA-PK. Preliminary studies demonstrate that micromolar levels of this inhibitor can be achieved in murine brain tissue and that MTX-241F exhibits promising single-agent efficacy and radiosensitizing activity in patient-derived DIPG neurospheres. Its physiochemical properties include high exposure in the brain, indicating excellent brain penetrance. Since radiotherapy results in double-strand breaks that are repaired by homologous recombination (HR) and non-homologous DNA end joining (NHEJ), we have tested the combination of MTX-241F with an inhibitor of ATM to achieve blockade of HR and NHEJ, respectively, with or without radiotherapy. When HR blockers were combined with MTX-241F and radiotherapy, synthetic lethality was observed, providing impetus to explore this combination in clinically relevant models of DIPG. Our data provide proof-of-concept evidence to support advanced development of MTX-241F for the treatment of DIPG. Future studies will be designed to inform rapid clinical translation to ultimately impact patients diagnosed with this devastating disease.
DDDR-06. THE SMOKING CESSATION AGENT LOBELINE DELAYS HYPOXIC STRESS RECOVERY RESULTING IN GLIOBLASTOMA CELL DEATH
Authors: Attwood Kathleen , Robichaud Aaron , Han Jae Ho , Wajnberg Gabriel , Roy Jeremy , Weeks Adrienne 
Published: November 2023

Abstract
Glioblastoma (GBM) is the most common and aggressive primary malignant brain tumour with a universally fatal prognosis. GBM is characterized by extensive regions of hypoxia which adversely impacts clinical outcomes, as hypoxia promotes chemoresistance. Tumour cells can adapt to and survive hypoxic stress by inducing rapid changes in the translational landscape, facilitated in part by the formation of stress granules (SGs). SGs are cytoplasmic aggregates of untranslated mRNAs and RNA binding proteins formed in response to a variety of cellular stressors, that allow cells to temporarily prioritize translation of stress-related proteins. Previous work in our laboratory has shown that GBM cells form SGs in vitro and in vivo, and that pharmacologically altering SG dynamics to prevent their dissolution (effectively locking cells in a stressed state) increases GBM cell death. Here we have identified another compound that delays the dissolution of hypoxia-induced SGs in GBM cells, the smoking cessation agent lobeline. SG dissolution typically occurs within 15 minutes post-hypoxia, however pre-treatment of immortalized GBM cells with lobeline delays SG dissolution for up to 2 hours. This delay in SG dissolution is dose dependent, as higher lobeline concentrations resulted in corresponding increases in the percentage of cells containing SGs and the average number of SGs per cell post-hypoxia. Lobeline also led to sustained phosphorylation of eIF2a (a key regulator of translation initiation) with an accompanying decrease in global protein translation levels post-hypoxia. Importantly, the combination of lobeline and hypoxia led to synergistic cell death in both immortalized and primary GBM cells, specifically through increased necrosis. Lobeline acts as a VMAT2 ligand and can stimulate dopamine release. Interestingly, we have found miRNA related to dopamine metabolism pathways overrepresented in extracellular vesicles isolated from GBM patient plasma. We postulate that disrupting the balance of stress pathways may have therapeutic potential in the future.
DDDR-07. TARGETING THE CIRCADIAN CLOCK WITH SMALL MOLECULE COMPOUNDS RESULTS IN ANTI-TUMOR EFFECTS SPECIFICALLY IN GLIOBLASTOMA STEM CELLS
Authors: Chan Priscilla , Wu Lian , Hovsepyan Anahit , Mkhitaryan Seda , Karapetyan Gevorg , Shah Khalid , Wakimoto Hiroaki , Kamenecka Theodore , Solt Laura , Cope Jamie , Moats Rex , Hirota Tsuyoshi , Rich Jeremy , Kay Steve 
Published: November 2023

Abstract
Glioblastoma multiforme (GBM) is the most common primary brain tumor, with an average survival time of less than one year following diagnosis. Treatment success remains challenging despite aggressive, multimodal current standard-of-care consisting of maximal surgical resection followed by concurrent temozolomide (TMZ) chemotherapy and radiation. The presence of GBM stem cells (GSCs) is thought to make treatment exceptionally difficult as they are highly invasive, resistant to chemoradiation, promote angiogenesis, support an immune suppressive environment, and can recapitulate the primary tumor following surgical resection. We have reported that GSCs, however, are dependent on core circadian clock proteins, Brain and Muscle ARNTL-Like 1 (BMAL1) and Circadian Locomoter Output Cycles Protein Kaput (CLOCK), which is not observed in differentiated GBM cells or normal neuronal stem cells. In this study, we explore the anti-GSC effects of multiple families of novel small molecule circadian clock compounds that either lower BMAL1 transcription (REV-ERB agonists) or inhibit BMAL1::CLOCK heterodimer transcriptional activity (Cryptochrome (CRY) stabilizers or Casein Kinase (CK) 1/2 inhibitors). Here we report that compared to compared to non-cancerous cells, U2OS human osteosarcoma cells, and differentiated GSCs (DGCs), GSCs display increased sensitivity to clock compounds at single agent and combinatory doses of clock compounds. Additionally, clock compounds are significantly more effective in targeting GSCs than TMZ and combinations of clock compounds with TMZ can lower TMZ IC50 value in different GBM cell lines and types. Application of the CRY stabilizer SHP1705 in GBM PDX patient derived xenograft (PDX) models resulted in decreased tumor growth rate and increased survival time compared to vehicle control. These results highlight the therapeutic potential of circadian clock compounds as single agents, in combinations and as adjuvants to existing therapies by specifically targeting the GSC population in GBM.
DDDR-08. DISCOVERY OF ER STRESS-INDUCING COMPOUNDS FOR GBM: A PROMISING APPROACH TOWARDS THERAPEUTIC DEVELOPMENT
Authors: Veliz Eduardo , Sansalone Lorenzo , Maldonado Amanda , Leblanc Roger , Steven Vanni , Graham Regina 
Published: November 2023

Abstract
The unfolded protein response (UPR) is a pro-survival mechanism triggered by cellular stresses encountered by tumor cells, such as hypoxia, acidosis, reactive oxygen species and even radiation and chemotherapy. In response to increased unfolded or mis-folded proteins in the endoplasmic reticulum (ER), the UPR initiates specific cell signaling pathways aiming to alleviate ER stress and restore ER proteostasis which include increasing the expression of chaperones to aid in protein folding, enhancing protein degradation and reducing global protein synthesis. However, if homeostasis cannot be restored, the UPR switches from survival to cell death. The UPR is a relatively novel therapeutic target for glioblastoma (GBM), and specifically GBM stem-like cells (GSCs) which maintain tumor heterogeneity, drive GBM tumor growth and therapy resistance. Here we tested a series of curcumin derivatives against three GSC lines and identified a trimethoxy bis-chalcone which promotes robust GSC death with an average IC50 of just below 300 nM, a 100-fold increase in activity compared to curcumin. Furthermore, this bis-chalcone was non-toxic to normal human mesenchymal stem cells. Western blot analysis indicated that the bis-chalcone induced robust activation of UPR pro-death protein C/EBP Homologous Protein (CHOP) while simultaneously decreasing the expression of pro-survival chaperone GRP78/Bip. Lastly our bis-chalcone induced caspase 7 expression and PARP cleavage indicating apoptosis. Most ER stress inducing agents promote both the survival, upregulation of Grp78, and cell death arms of the UPR. Here we identified a compound that only promotes UPR cell death signaling and is highly toxic to radiation and temozolomide resistant GSCs while demonstrating no toxicity to non-tumor cells. This is a promising lead compound for the development of UPR targeted GSC/GBM therapeutics.
DDDR-09. FUNCTIONAL GENOMICS AND CHEMOTHERAPY RESISTANCE SCREENING IDENTIFIES BIOMARKERS AND TARGETABLE MECHANISMS OF CCNU RESISTANCE IN GLIOMAS
Authors: Hajal Cynthia , Dalin Simona , Raskind Greg , Cusick Margaret , Malinowski Seth , Ito Jakob , Bossi Connor , Vogelzang Jayne , Bellamy Charlotte , Salhi Lisa , Bielle Franck , Getz Gad , Bandopadhayay Pratiti , Touat Mehdi , Beroukhim Rameen , Ligon Keith 
Published: November 2023

Abstract
The bifunctional alkylator lomustine (CCNU) remains widely but heterogeneously used as one of the few effective treatments in glioblastoma (GBM) and IDH mutant gliomas. Despite its widespread use, mechanisms of response and resistance to this agent are controversial and patients who benefit are poorly understood. To address this with next-generation patient models and functional genomics approaches, we generated and characterized CCNU response in a large cohort of 71 patient-derived glioma cell lines (PDCLs, spheroids/organoids). Models had fully defined clinical and molecular characteristics (WES, RNAseq, and patient and model MGMT). Patient models, including those derived from patients who acquired resistance to CCNU, exhibited a surprisingly wide range of differential response to CCNU (median IC50: 21.66uM; range: 1.52uM-159uM) using metabolic (CTG) as well as cell death readouts, with no lines showing complete resistance (EC100 &lt; 291uM). MGMT promoter methylation status but not mismatch repair (MMR) trended, but did not reach, statistical significance as a predictor of CCNU sensitivity (p=0.053), in striking contrast to TMZ (p=0.01). Chronic CCNU exposure of two PDCLs led to acquired resistance to CCNU (IC50 increase from 5uM to 50uM on average). RNA sequencing showed 194 significantly differentially expressed genes while no mutations acquired in resistant models were identified in DNA sequencing. PRISM pooled screening of over 900 barcoded cancer cell lines and correlation with DepMap whole genome CRISPR-knockout data showed unique patterns of CCNU response and strong upregulation of DNA repair targets in the resistant state, which differed from TMZ. Shared targets were also identified in a CRISPR-activator screen performed on a CCNU sensitive cell line in the presence and absence of CCNU and converged on multiple mTOR pathway genes as top enriched targets and biomarkers of resistance in CCNU-resistant models. These druggable targets are currently being investigated for combination therapies with CCNU and potential to overcome resistance.