bluuebunny/crossref_metadata_2025 huggingface dataset:
DDDR-35. TARGETING GBM INVASION BY INHIBITING KCNA1 WITH 4-AMINOPYRIDINE: AN FDA APPROVED DRUG THAT EASILY PASS THROUGH THE BBB
Authors: Xiao Sophie , Li Lin , Yang Deying , Zhang Huiyuan , Huang Yulun , Teo Wan-Yee , Patel Akash , Du Yuchen , Li Xiao-Nan
Published: November 2022

Diffuse invasion is a hall mark of glioblastoma (GB) and one of the primary causes of poor clinical outcomes in GBM patients. Tumor cells migrate deep into the normal brain tissues are frequently protected by the BBB, making them particularly difficult to treat. New therapeutic targets are needed. Our previous studies using spatially dissected and functionally validated matching pairs of invasive and tumor core GBM cells identified KCNA1 as a shared gene that is selectively over-expressed in the invasive GBM cells in 6 patient derived orthotopic xenograft (PDOX) mouse models of pediatric GBM (Huang YL et al, Adv Science 2021). A subsequent analysis of adult GBM RNAseq data from IVY Atlas revealed a significantly elevated expression of KCNA1 (4.9 fold) in the invasive edges of patient GBM tumors. It is also one of the 11 core molecules identified in GEO and TCGA databases through an integrated bioinformatic analysis (Yang J, Front Onc 2021). To determine the anti-invasive activities of targeting KCNA1, we treated three highly invasive adult GBM PDOX models with 4-aminopyridine (4-AP), an old lipid soluble drug that easily penetrate the BBB, at 5 mg/kg, i.p., 5 days/week for 8 weeks acing alone or in combination with fractionated radiation (at 2 Gy/day x days). As single agent, 4-AP significantly extended median animal survival times in 1/3 GBM models (69 to 77 days, P = 0.033). Combination with XRT did not significantly improve the animal survival times in the three models. Systematic analysis of GBM invasion in mouse brains of the 3 PDOX models before, during and after 4-AP treatment revealed remarkable inhibition of tumor invasion. Our data highlighted the role of KCNA1 in promoting GBM invasion and support the fine tuning of 4-AP dose, schedule, and length of treatment to serve as a novel component of anti-GBM invasion therapies.
DDDR-37. GB5121 IS A NOVEL, IRREVERSIBLE, COVALENT BTK INHIBITOR WITH HIGH SELECTIVITY AND CNS-PENETRANCE FOR TREATMENT OF CNS MALIGNANCIES
Authors: Yusuf Isharat , Guimond David , Naiman Zachary , Schiff Theodore , Clemons Bryan , Paulson Bryanna , Hou Kay , Meadows Kristen Taylor , Rose Mark , Carter Laura
Published: November 2022

Inhibitors of Bruton’s tyrosine kinase (BTK) are approved treatments for several B cell lymphomas. However, they are characterized by modest selectivity and/or limited central nervous system (CNS) exposure which is important in instances of CNS disease. GB5121 is an orally available, selective, irreversible, covalent small molecule BTK inhibitor that was designed to address these limitations. Here, GB5121 was profiled for selectivity, potency, inactivation kinetics and CNS penetrance in comparison to ibrutinib. GB5121 pharmacodynamic properties were evaluated using both cell-free enzymatic and cell-based functional assays, showing nM potency for BTK inhibition and rapid BTK inactivation kinetics (Kinact/Ki) in both peripheral and CNS tissue, a critical parameter for irreversible inhibitors. In a kinome scan, GB5121 exhibited high kinase selectivity against 349 kinases with only TEC/TXK demonstrating > 50% inhibition at 1 µM; GB5121 did not inhibit phosphorylation of EGFR in a cell-based assay. When compared with other BTK inhibitors, GB5121 showed superior CNS target occupancy using a probe-based ELISA measuring free BTK in the brain of mice receiving 3 daily oral doses. GB5121 also demonstrated significantly higher brain to plasma ratio in mice with an intact blood brain barrier. In non-human primates, a 1:1 brain to plasma concentration ratio was demonstrated for GB5121 for up to 8 hours with both oral (30 mg/kg) and IV (2 mg/kg) doses. Together, these features differentiate GB5121 from both FDA-approved BTK inhibitors, as well as those currently under clinical investigation. Our data supports the use of GB5121 in clinical trials where BTK is a known driver of malignancies, including CNS lymphoma. This research has been previously presented at the AACR Annual Meeting 2022.
DDDR-38. A LENTIVIRAL CRISPR SCREEN FOR EPIGENETIC MODULATORS OF CAR T CELL-TARGETED ANTIGENS IN GLIOBLASTOMA CELL LINES
Authors: Jordan Walter T , Ayad Nagi
Published: November 2022

Glioblastoma is the most common malignant brain tumor. Unfortunately, outcomes for this cancer are poor. Even with standard of care treatment, the median survival time is only 15 months and the disease is almost universally lethal. Therefore, more effective therapies are urgently needed to treat this condition. One promising treatment is chimeric antigen receptor (CAR) T cell therapy. CAR T cells are white blood cells that are engineered to kill cancer cells expressing certain antigens; however, the potential of this treatment has yet to be fully realized and further work is required for it to be more effective. One strategy for augmenting CAR T cell therapy would be to increase the expression of the targeted antigens on cancer cells. This could be done using small molecule inhibitors of epigenetic pathways that regulate expression of these antigens. Therefore, the goal of this study was to screen for epigenetic genes that regulate expression of antigens currently being targeted in CAR T cell clinical trials for glioblastoma. Using a CRISPR/Cas9 lentiviral vector library, we knocked out various genes encoding epigenetic proteins in human glioblastoma cell lines. Flow cytometry was used to sort for cells with the highest levels of target surface antigen expression. Genomic DNA was isolated from the cells with the highest surface expression of the antigens of interest. The isolated DNA was sequenced to identify the genetic manipulations responsible for increased antigen expression. Future studies will use small molecule inhibitors of the identified epigenetic modulators to augment CAR T cell therapy in mice.
DDDR-40. OVERCOMING DRUG RESISTANCE BY TARGETING AUTOPHAGY REGULATED BY A LONG INTERGENIC NONCODING RNA
Authors: Zhang Alexander , Sheng Zhi , Pridham Kevin
Published: November 2022

BACKGROUND

Autophagy is a self-eating process that supports cancer cell survival. Autophagy activation during drug treatment often prolongs cancerous cell survival, causing drug resistance, as seen in glioblastoma multiforme (GBM) to temozolomide (TMZ). Thus, blocking autophagy is an appealing approach to overcoming cancer drug resistance. Long noncoding RNAs (LincRNAs) have emerged as potential targets. LincRNA LINC00467 (renamed ARLINC) was recently identified as a potential autophagy inhibitor in cancer cells. However, ARLINC’s mechanism of inhibition and whether its modulation can suppress autophagy in cancer remains unknown.

OBJECTIVE

Research Question: Can blocking autophagy restore the sensitivity of cancer cells to chemotherapy? Hypotheses: 1) ARLINC regulates chemotherapy drug sensitivity by inducing autophagy. 2) Overexpression of ARLINC can increase chemotherapy drug sensitivity, as measured by cell viability and autophagy assays

METHODS

Aim 1) Endogenous ARLINC levels in GBM cell lines will be measured using qRT-PCR. Aim 2) Cell viability of GBM upregulated with pBabe-ARLINC (experiment) and pBabe (control) then exposed to increasing concentrations of TMZ will be analyzed using MTS assay. Student’s T-test will be used to determine significance. Aim 3) Autophagy flux will be measured in GBM lines that are transiently transfected with ARLINC compared to the empty vector via Cyto-ID assay.

RESULTS

Aim 1: Compared to Normal Human Astrocytes (NHA), U87MG had higher levels, LN18 and SF295 and lower, and LN229 had around the same levels of ARLINC. Aim 2: MTS cell viability assays in SF295 upregulated with ARLINC showed no significant decrease in TMZ sensitivity. Aim 3: Cyto-ID in U87MG and LN229 upregulated with ARLINC showed no significant decrease in autophagy flux.

CONCLUSIONS/FUTURE WORK

Results show no effect of ARLINC upregulation on cell viability and autophagy flux. Future work involves knockdown experiments to decrease intracellular levels of ARLINC and determine the effects of upregulation of autophagy on sensitization.
EOLP-03. A RETROSPECTIVE STUDY ON CAUSE OF DEATH DUE TO HIGH-GRADE GLIOMAS IN PEDIATRIC VERSUS ADULT PATIENTS
Authors: Franson Andrea , Junck Larry , Lyons Samantha
Published: November 2022

BACKGROUND

Limited literature exists on the presumed pathophysiologic mechanisms by which children, adolescents and adults die from high-grade gliomas (HGGs). This study aims to identify the likely specific cause of death in patients with HGG based on imaging review in proximity to death. A secondary aim is to assess the use and timing of palliative care/hospice in patients with HGG. We hypothesized that most patients with HGG, both adult and pediatric, die from primary neurologic failure as a result of local tumor progression, with additional causes including hydrocephalus with subsequent brainstem herniation or causes indirectly related to tumor progression such as systemic infection.

METHODS

We conducted a retrospective review of pediatric patients with WHO Grade 4 gliomas and adults with de novo Grade 3 or 4 gliomas or Grade 2 glial tumors that transformed to Grade 3/4, diagnosed from 2016 to 2021 at Michigan Medicine (IRB exemption obtained). We reviewed imaging and clinical records of patients who had brain MR and/or CT imaging within 3 - 6 weeks of death to determine a likely cause of death.

RESULTS

Twenty-six pediatric patients and 43 adult patients identified met inclusion criteria. Initial analysis reveals that the majority of patients with HGG died from local tumor progression and subsequent neurologic failure. We also noted a greater use of palliative care/hospice services in pediatric patients, with less frequent referral for adult patients at any time in their disease course. Pediatric patients are almost always supported by Child and Family Life, while psychological services are rarely received by adult patients.

CONCLUSIONS

Analysis is ongoing, though trends indicate that the primary cause of death in patients with HGG is through primary neurologic failure, and that there may be opportunities to lessen end-of-life suffering through patient education and the use of support services.
EPID-02. ANTIBODY REACTIVITY TO VARICELLA-ZOSTER VIRUS AND THREE OTHER HERPESVIRUSES AND SURVIVAL IN ADULTS WITH GLIOMA
Authors: Guerra Geno , Francis Stephen , McCoy Lucie , Hansen Helen , Rice Terri , Molinaro Annette , Wiencke John , Wrensch Margaret
Published: November 2022

Measures of Varicella-Zoster virus (VZV) have been consistently inversely associated with glioma risk, but the association with glioma survival has not been investigated. In this study we analyzed overall survival of individuals with glioma in relation to measured levels of antibodies to 4 common viral infections, measured post-diagnosis.

METHODS

We utilized immunoglobulin G (IgG) antibody measurements to VZV, Epstein-Barr virus (EBV), herpes simplex virus (HSV), and cytomegalovirus (CMV), collected from 1378 patients newly enrolled in the UCSF Adult Glioma Study between 1991-2010. Blood was obtained a median of 3 months post diagnostic surgery. Subject follow-up for survival is ongoing. The associations of IgG levels with overall survival were estimated using Cox models adjusted for age, sex, race, type of surgery, dexamethasone usage, and stratified by tumor grade.

RESULTS

The 1378 glioma patients studied had median survival of 2.1 years. VZV antibody seropositivity was associated with improved survival outcomes (Hazard ratio, HR = 0.70, 95% Confidence Interval 0.54-0.90, p = 0.0061), with a grade-IV specific association (HR=0.65, 0.48-0.87, p=0.0046). Amongst VZV seropositive cases, those in the bottom quartile of measured seroreactivity had significantly worse survival outcomes as compared to the upper three quartiles (HR = 1.31, 1.13-1.52, p = 0.0003). Antibody seropositivity to EBV was also associated with improved survival times (HR = 0.71, 0.53-0.96, p = 0.028). Antibody response to two other common viruses (CMV, HSV) were not associated with glioma survival (p = 0.213, p = 0.215, respectively).

CONCLUSION

This is the first study, to our knowledge, to associate virus-specific antibody levels with survival amongst glioma patients. These associations do not appear to be due to general tumor-induce immune suppression. Our results controlled for dexamethasone usage, a known immunosuppressor. IgG measurements were taken post-glioma diagnosis, therefore further study is needed to determine the direction of causation, and if anti-herpesvirus treatment, such as VZV vaccination, might be beneficial for glioma prognosis.
EPID-03. PATHOGENIC GERMLINE MUTATIONS IN GLIOMA PATIENTS
Authors: Mandel Jacob , Jalali Ali , Patel Akash , McDonald Malcolm , Prather Lyndsey , Helfer Cassandra , Gu Xiangjun , Ludmir Ethan , Echeverria A J , Rao Ganesh , Dhar Shweta , Amos Chris
Published: November 2022

BACKGROUND

No consensus germline testing guidelines currently exist for glioma patients. Hence such testing is not routinely performed. The prevalence and type of germline pathogenic variants in these brain tumors remains unknown. DESIGN/

METHODS

A retrospective review of patients treated at Baylor College of Medicine with paired tumor/normal sequencing using the Tempus xT tumor/normal matched approach from August 2018- April 2022 was performed. Corresponding clinical data was collected for these patients.

RESULTS

We identified 152 glioma patients of which 15 (9.8%) had pathogenic germline variants. Pathogenic germline variants were seen in 11/84 (13.1%) of Glioblastoma, IDH wildtype, 3/42 (7.1%) of Astrocytoma, IDH mutant and 1/26 (3.8%) of Oligodendroglioma, IDH mutant and 1p/19q co-deleted patients. Pathogenic variants in BRCA2, MUTYH and CHEK2 were seen more commonly (3/15 or 20% each). BRCA1 variants were seen in 2/15 (13%) patients, with variants in NF1, ATM, MSH2, and MSH3 occurring in one patient (7%) each. Second hit somatic variants were seen in 3/15 patients (20%). A second somatic hit was seen in NF1, MUTYH and MSH2 in one patient (7%) each. Referral to genetics was performed in 6/15 (40%) patients with pathogenic germline variants. Median overall survival was 1.6 years for glioblastoma, IDH wildtype patients with a pathogenic germline variant compared to 1.79 years for glioblastoma, IDH wildtype patients without it (p = 0.67).

CONCLUSIONS

Although not routinely performed in glioma patients, pathogenic germline variants occurred in ~10% of our patients. Only 40% of these patients were referred to genetics. These findings suggest a possible overlooked opportunity for determination of hereditary cancer syndromes with impact on surveillance as well as potential broader treatment options. Further research to confirm the occurrence and types of pathogenic germline variants in patients with IDH wildtype compared to IDH mutant tumors is necessary.
EPID-04. IMPACT OF SEX DIFFERENCES IN IRON SUPPLEMENTATION AND OUTCOMES IN ANEMIC GLIOBLASTOMA PATIENTS
Authors: Shenoy Ganesh , Khunsriraksakul Chachrit , Palsa Kondaiah , Khristov Vladimir , Lathia Justin , Barnholtz-Sloan Jill , Connor James
Published: November 2022

We performed a retrospective sex-stratified analysis on 1750 histologically confirmed surgical glioblastoma patients (737 female, 1013 male) diagnosed between January 1, 2000 – January 1, 2020 in the TriNetX Research Network. Among 737 female glioblastoma patients, 140 (18.99%) were classified as anemic (defined as having mean 5-year-post-diagnosis hemoglobin levels < 12 g/dL). Among 1013 male patients, 177 (17.4%) were classified as anemic (mean 5-year-post-diagnosis hemoglobin levels < 13 g/dL). Of the 140 anemic female patients, 30 (21.4%) received iron supplementation whereas 28 (15.8%) of 177 anemic male patients received iron supplementation. Anemic female patients receiving iron supplementation were on average younger than anemic female patients who did not receive supplementation (mean age at diagnosis (SD): 59.08 vs. 64.87, p = 0.037), however no statistically significant differences in presence of chemotherapy administration, radiation administration, or Charlson comorbidity index (CCI) were detected. Anemic male patients receiving iron supplementation had no significant difference in mean age at diagnosis, chemotherapy administration, radiation administration, or CCI compared to anemic male patients not receiving iron supplementation. Kaplan-Meier analysis revealed that iron supplementation in anemic female patients was associated with prolonged overall median survival (536 vs. 361 days, p = 0.03) whereas iron supplementation in anemic male patients was not associated with any significant increase in overall survival (392 vs. 361 days, p = 0.89). Multivariate analysis using a Cox proportional hazards model adjusted for mean 5-year-post-diagnosis hemoglobin levels, age at diagnosis, chemotherapy administration, radiation administration, and CCI revealed that iron supplementation was associated with improved survival in anemic female patients (HR: 0.53, 95% CI: 0.30 – 0.96) but not in anemic male patients (HR: 0.87, 95% CI: 0.54 – 1.43). These results highlight the importance of iron biology in glioblastoma and provide evidence for further investigation into iron supplementation of anemic glioblastoma patients.
EPID-05. LEPTOMENINGEAL METASTASES IN GLIOMA REVISITED: HIGH INCIDENCE AND THEIR MOLECULAR PREDICTORS BASED ON RECENT IMAGING AND MOLECULAR DIAGNOSTICS
Authors: Park Yae Won , Ahn Sung Soo , Chang Jong Hee , Kim Se Hoon , Lee Seung-Koo
Published: November 2022

BACKGROUND

Leptomeningeal metastases (LM) in glioma has been underestimated due to low incidence and lack of reliable imaging. This study aimed to investigate a real-world incidence of LM using a CSF-sensitive MR imaging technique and analyze molecular predictors for LM in the molecular era.

METHODS

Total 1,405 adult glioma patients underwent post-contrast fluid attenuated inversion recovery (FLAIR) imaging at initial diagnosis and during treatment monitoring between March 2001 and October 2021. Molecular data included isocitrate dehydrogenase (IDH) mutation, 1p/19q co-deletion, H3 K27M alteration, and O6-methylguanine-methyltransferase (MGMT) promoter methylation status. Multivariable logistic regression analysis for LM development was performed in molecular data, clinical data, and imaging characteristics. Median overall survival (OS) was compared between patients with and without LM using Kaplan-Meier survival curves and log-rank test.

RESULTS

LM was identified in 16.2% of glioma (228 of 1405), with 7.8% (110 of 1405) at initial diagnosis, and 8.4% (118 of 1405) at recurrence. Among molecular diagnostics, IDH-wildtype (odds ratio [OR] 3.14, P = .001) and MGMT promoter unmethylation (OR 1.43, P = .034) were independent predictors of LM. WHO grade 4 (OR 10.52, P < .001) and nonlobar location (OR 1.54, P =.048) were associated with LM at initial diagnosis, whereas IDH-wildtype (OR 5.04, P < .001) and H3 K27M alteration (OR 3.39, P =.003) were significantly associated with LM at recurrence. Patients with LM had a worse median OS than those without LM (16.7 vs. 32.0 months, log-rank test; P < .001).

CONCLUSIONS

CSF-sensitive MR imaging diagnostics aid diagnosis of LM and reduced an underdiagnosed condition in adult gliomas. Molecular markers affect LM at initial diagnosis and at recurrence, and patients with aggressive molecular markers warrant imaging surveillance of LM.
EPID-09. AGE-STRATIFIED SURVIVAL ANALYSES OF CO-MORBIDITIES IN PATIENTS WITH GRADE IV GLIOMAS
Authors: Rabin Erik , Mi Xinlei , Huang Jonathan , Kim Miri , Mozny Andreas , Amidei Christina , Sieg Erica , Bell April , Zhai Lijie , Bommi Prashant , Lauing Kristen , Lukas Rimas , Wainwright Derek
Published: November 2022

Glioblastomas are the most common primary malignant brain tumor in adults. Subject age is a strong prognostic factor for survival. We performed a co-morbidity analysis of younger vs. older (greater than 65 years) adults with grade IV gliomas (GIV) to understand inherent differences that vary with subject age. Electronic health records for 1,208 GIV patients were collected at a single center between 1/1/2000 and 9/8/2021 and used to construct a multivariable time-dependent cox model that examined intra-cohort hazards associated with 33 measures of co-morbidity and tumor related symptoms. The date of GIV diagnosis was identified as the start time, and subject death was used to define event time. Patients that were alive or lost to follow-up were censored at the last recorded date. Survival time was calculated as the difference between diagnosis date and event time or censorship. GIV was stratified by IDH and MGMT promoter methylation status when available. Younger patients experienced a greater hazard with: limitations to movement (1.88 [1.46, 2.43] ****), gait (1.72 [1.17, 2.52] **), weakness (1.96 [1.26, 3.06] **), seizures (1.28 [1.04, 1.58] *), epilepsy (1.47 [1.09, 1.99] *), and anxiety disorders (2.37 [1.44, 3.92], **). Older GIV patients experienced an increased hazard with: confusion and altered mental status (4.3 [2.08, 8.89], ****). Both age groups experienced increases with eye/visual systems and plegia. These data indicate novel comorbid enrichments varying by subject age that, from a mechanistic perspective, may be used to better understand why older adults with GIV survive significantly less than younger counterparts.
EPID-12. REGIONAL VARIATIONS IN THE INCIDENCE OF BRAIN GLIOMA IN ADULTS IN ALABAMA
Authors: Lobbous Mina , Abdelrashid Moaaz , Estevez-Ordonez Dagoberto , Markert James , Tipre Meghan , Brown Elizabeth , Nabors Louis , Lewis Cora
Published: November 2022

BACKGROUND

Gliomas are the most common primary brain tumor in adults in the US with an annual age-adjusted incidence rate (AAA-IR) of 4.67 to 5.73 per 100,000 persons. There are several sources of carcinogenic contaminants in northeast Alabama and western Georgia with the Coosa River serving as the region’s primary water source. We aimed to examine the incidence rate of glioma, as well as tumor characteristics and overall survival, in northeast Alabama compared to the rest of the state.

METHODS

This is a retrospective cohort study using the UAB Neuro-Oncology clinic database including adult patients ( ≥ 20 years at diagnosis) with histologically confirmed diagnosis of glioma (ICD10: 71.9) residing in the state of Alabama at the time of diagnosis between January 2015 and December 2019. We calculated AAA-IR among residents in counties intersected by the Coosa River in northeast Alabama (exposed group) compared to the rest of the state (non-exposed group). The electronic medical records of the participants were reviewed for patient demographics, insurance status, tumor grade and molecular markers, as well as the vital status. The overall survival was graphically examined using Kaplan-Meier.

RESULTS

A total of 660 patients were included in this study (528 non-exposed, and 132 exposed). The AAA-IR of glioma in the exposed group was 4.76 per 100,000 persons vs 3.14 per 100,000 persons in the non-exposed group with a 50 % higher incidence rate of glioma in the exposed group (RR = 1.50; 95% CI, 1.22-1.89). There was no statistically significant difference between the two groups with respect to age at diagnosis, sex, race, surgery type, tumor grade, IDH status, or overall survival.

CONCLUSIONS

Our findings indicate a higher incidence of glioma in northeast Alabama. Future geospatial and population-based epidemiological investigations are needed to identify possible regional environmental risk factors and examine temporal sequence.
EPID-14. EPIDEMIOLOGICAL SURVEY OF RADIATION-INDUCED MENINGIOMA: A SEER ANALYSIS
Authors: Abaricia Jefferson , Matharoo Jashanjeet , Opalak Charles , Broaddus William
Published: November 2022

OBJECTIVE

Radiation-induced meningioma (RIM) is a rare but serious consequence of cranial and cranio-spinal external beam radiation therapy (EBRT). While recent studies have characterized the epidemiological features of RIM in small populations or systematic reviews, none have studied RIM within a national database for a more generalizable description of this disease entity. The objective of this study was to identify and characterize the population with RIMs within a large national database.

METHODS

From the SEER Research Plus Nov 2020 (1975-2018) dataset, 56161 patients treated with EBRT for the following indications were identified: ocular/orbital tumors, brain/nervous system tumors, and leukemias. Next, a sub-population of 185 RIM patients, defined by histologically distinct precedent tumor treated with EBRT and a minimum 5-year latency from EBRT to meningioma, was identified. RIM prevalence, latency, pathologic behavior, and multiplicity were determined, and comparisons were made by sex, race, and original indication for EBRT.

RESULTS

The prevalence of RIM among the EBRT population was 0.33%. Among RIM patients, 41.62% were male and 84.32% were Caucasian. Average latency to RIM development was 23.39 ± 8.65 years, with no significant difference between sexes or races. Fourteen patients had multiple RIMs at diagnosis, while four patients experienced recurrent RIM. RIMs classified as “malignant” had a shorter latency (16.30 years) than “borderline” (26.11 years) or “benign” (23.36 years) RIMs. Of the most common original EBRT indications, precursor lymphoblastic leukemia (29.89 years) had longer latency to RIM than medulloblastoma (21.57 years) or astrocytoma (22.67 years); this may be explained by lower doses of radiation used for lymphoblastic leukemia treatment.

CONCLUSION

These data provide novel epidemiological information—most importantly, prevalence—of RIM in a nationwide population, and they suggest that RIM occurs in patients independent of sex or race. These findings will aid clinicians in explaining the risk of RIM development to patients undergoing EBRT.
EPID-18. IATROGENIC IMMUNODEFICIENCY ASSOCIATED LYMPHOPROLIFERATIVE DISORDERS OF THE CENTRAL NERVOUS SYSTEM: A TREATMENT PARADOX
Authors: Tadipatri Ramya , Ekhator Chukwuyem , Narayan Ram , Azadi Amir , Yuen Kevin , Grewal Jai , Fonkem Ekokobe
Published: November 2022

BACKGROUND

Primary central nervous system lymphomas (PCNSLs) have historically had dismal survival rates until the advent of high-dose methotrexate (HD-MTX) based chemotherapy regimens. With increasing prevalence of autoimmune disease and development of new immunosuppressants, a genetically distinct entity known as iatrogenic immunodeficiency associated lymphoproliferative disorder (LPD) has emerged. Many of these cases arise following methotrexate use, challenging feasibility of standard HD-MTX regimens. The aim of this study was to further characterize this disorder and determine the optimal management strategy.

METHODS

We describe a case of a 76-year-old female with iatrogenic immunodeficiency associated PCNSL successfully treated with surgical resection followed by an antiviral and rituximab based regimen. We then performed a systematic literature review and identified 58 cases of non-transplant iatrogenic immunodeficiency associated LPD involving the CNS. We used a linear probability statistical model to determine correlations with outcome.

RESULTS

Natalizumab was associated with EBV negative tumors (p = 0.023), and EBV positive tumors were associated with improved outcomes (p = 0.016). Surgical resection was associated with improved outcomes (p = 0.032), although limited by potential confounding effect. Antiviral treatment (p = 0.095), rituximab (p = 0.111), and SCT (p = 0.198) showed a trend toward improved outcomes. The remaining treatments including methotrexate showed no improvement.

CONCLUSION

We propose that surgical resection, rituximab, and antiviral treatment may be considered as an alternative to standard HD-MTX based regimens when managing iatrogenic immunodeficiency associated LPD of the CNS. Further study through prospective cohort studies or randomized clinical trials is warranted.
EPID-20. MORTALITY TRENDS IN PRIMARY MALIGNANT BRAIN AND CENTRAL NERVOUS SYSTEM TUMORS VARY BY HISTOPATHOLOGY, AGE, RACE, AND SEX
Authors: Thierheimer Marisa , Cioffi Gino , Waite Kristin , Kruchko Carol , Ostrom Quinn , Barnholtz-Sloan Jill
Published: November 2022

BACKGROUND

Primary malignant brain and other central nervous system tumors (BT) are rare cancers that have shown rising mortality rates in recent years. To elucidate potential factors involved in this rising death rate, we examined mortality trends for primary malignant BT in the United States (US) stratified by histopathology groupings, age, race, and sex.

METHODS

Mortality rates for demographic factors within primary malignant BT were generated using the Center for Disease Control’s National Vital Statistics Systems (NVSS) data from 2004 to 2018. Additionally, histopathology-specific incidence-based mortality rates were calculated using the National Cancer Institute’s Surveillance, Epidemiology, and End-Results (SEER) 18 data from 2004 to 2018. Joinpoint modeling was used to estimate mortality trends and annual percent changes (APC) with corresponding 95% confidence intervals (CI).

RESULTS

Overall, there was a very small increase in mortality from 2004-2018 (NVSS, APC: 0.3%, 95% CI: 0.1%-0.5%). Individuals 65+ years of age saw a small increase in mortality (NVSS, APC: 0.6%, 95% CI: 0.4%-0.9%), while changes in individuals of other ages were non-significant. Asian/Pacific Islander or American Indian/Alaskan Native had the largest increase in mortality (NVSS, APC: 1.6%, 95% CI: 0.7%-2.4%). Overall mortality trends by sex were similar. Among histopathology groupings, there was a small mortality increase in adults ages 65+ years with glioblastoma (SEER, APC: 0.5%, 95% CI: 0.1%-1.0%), while patients with other glioma and non-glioma did not show significant changes in mortality. In pediatric patients (ages 0-14 years), high-grade glioma mortality increased significantly from 2004-2015 (SEER, APC: 7.0%, 95% CI: 3.8%-10.3%) but had a non-significant decrease from 2015-2018. Pediatric patients with embryonal tumors had a significant mortality decrease between 2004 and 2018 (SEER, APC: -1.9%, 95% CI: -3.3%-0.5%).

CONCLUSION

Examining age, race, sex, and histopathology-specific mortality at the population level can provide important information for clinicians, researchers, and aid in public health planning.
EPCO-04. TRANSCRIPTIONAL AND CHROMATIN-ACCESSIBILITY HETEROGENEITY IN IDH-MUTANT GLIOMAS
Authors: Lyne Anne-Marie , Ducray François , Cavalli Florence
Published: November 2022

Diffuse gliomas are a common type of adult brain tumour, comprising about 80% of adult malignant brain tumours, and are incurable. IDH-mutant gliomas, oligodendroglioma and astrocytoma, can be treated initially but eventually recur and are generally fatal. In this study, we profiled and analysed 23 frozen samples from primary and recurrent IDH-mutant glioma patients with single nucleus multiome sequencing (RNA- and ATAC-seq). In total we assayed around 70,000 malignant cells as well as 30,000 cells from the tumour microenvironment. Using a matrix factorisation approach, we characterised biological signals in the malignant cells from each sample, thereby identifying known and novel processes which vary within and recur across samples. Trajectory analysis was used to reconstruct the developmental hierarchy in IDH-mutant glioma and to investigate plasticity at different hierarchy levels, highlighting differences and similarities across patients and cancer types. Finally, master regulators, which drive malignant transcriptional programs were identified, using the complimentary and concurrent RNA and chromatin accessibility assays. This study provides a unique opportunity to investigate the transcriptomic and epigenetic heterogeneity present in gliomas, as well as the events leading to the development of more aggressive and treatment-resistant glioma tumours.
EPCO-07. NON-GENOMIC DETERMINANTS OF TUMOR CELL PHENOTYPES IN ADULT GLIOBLASTOMA
Authors: Zador Zsolt , Mikolajewicz Nicholas , Han Hong , Chokshi Chirayu , Venugopal Chitra , Maich Will , Jason Moffat , Singh Sheila
Published: November 2022

Non-genomic determinates of oncogenic cellular phenotypes is an emerging concept that expanded our model of tumor hallmarks. We hypothesized that oncogenic programs in adult glioblastoma (GBM) such as angiogenesis, proliferation, DNA repair, epithelial to mesenchymal transition and quiescent states are achieved independently of mutational background or clonal linage. We therefore explored the assortations of large-scale chromosomal rearrangements and canonical driver mutations with oncogenic programs in single cell RNA sequencing (scRNA-seq) of over 3000 tumor cells in 4 adult GBM using open data. We find recurring patterns where tumor cells from diverse mutational background and clonal linage converge upon oncogenic tumor phenotypes. We validate this observation in 9 tumors comprising over 16,000 cells and in xenograft animal models of GBM pre- and post temozolamide treatment. We finally explore the epigenetic associations of oncogenic phenotypes via computational label transfer from scRNA-seq to chromatic accessibility data from single cell ATAC sequencing (scATAC-seq). We find open genomic regions associated with canonical regulators, such as the highly oncogenic mesenchymal phenotype driven by TWIST1. Our results suggest a paradigm shift towards non-genetic determinants of oncogenic phenotypes in GBM complementing the conventional concept of cancer clonal evolution.
EPCO-10. SYSTEMS BIOLOGY-BASED THERAPEUTIC PREDICTIONS WITH GBMSYGNAL AND CLINICAL CORRELATES IN THE REAL-WORLD LONGITUDINAL OUTCOMES REGISTRY XCELSIOR
Authors: Stuhlmiller Timothy , Turkarslan Serdar , Friedland Julie , Shapiro Mark , Kesari Santosh , Patel Anoop , Baliga Nitin
Published: November 2022

Glioblastoma is an aggressive disease with multiple disrupted signaling networks in the same tumor, demanding the development of personalized combination regimens. Using SYstems Genetics Network AnaLysis we analyzed TCGA multiomics datasets for 422 glioblastoma patients to generate a predictive disease network model (gbmSYGNAL). This model seeks to uncover how subsets of mutations causally modulate regulators (transcription factors, miRNAs, etc.) that mechanistically regulate gene modules (“regulons”) associated with disease progression. Using the real-world registry XCELSIOR (NCT03793088), we identified 55 anti-cancer therapies utilized in glioblastoma treatment (N = 354 patients) and associated them with positive or negative regulon activity within individual patients across the TCGA cohort. A median of 12 regulons were targeted by each drug. Interestingly, nilotinib targeted only 5 regulons but they were found to be active in 38% of patients and regulons overactive in >35% of patients were targeted by repurposed anti-cancer drugs including celecoxib, hydroxychloroquine, and tocilizumab. Standard-of-care treatments lomustine and bevacizumab were predicted to be active in only 28% and 23% of patients, respectively. Using gbmSYGNAL, we then prioritized drugs for 12 additional patients from the XCELSIOR registry. Median overactive regulons per patient was 110 (range 55-254) represented by a median 28 molecular targets (range 17-37). Surprisingly, regulons targeted by metformin were predicted to be overactive in all patients. Certain regulons displayed a binary pattern (high “on” activity or completely “off” per patient) including those targeted by pemetrexed, pembrolizumab, and valproic acid while others showed a gradient of activity across patients including selinexor, panobinostat, palbociclib, and alpelisib. Systems biology analysis of commercially available NGS data combined with the XCELSIOR direct patient engagement platform yielded therapeutically actionable insights for glioblastoma patients in real time. Correlation with clinical outcomes is ongoing for ~50 additional patients and will be presented at the meeting.
EPCO-13. IDENTIFYING REGULATORS OF GLIOMA CELL STATE DIVERSITY AND EVOLUTION VIA JOINT SINGLE NUCLEUS RNA AND CHROMATIN ACCESSIBILITY
Authors: Johnson Kevin , Anderson Kevin , Nehar-Belaid Djamel , Varn Frederick , Gujar Amit , Courtois Elise , Robson Paul , Moon Hyo-Eun , Golebiewska Anna , Paek Sun Ha , Niclou Simone , Verhaak Roel
Published: November 2022

Glioma cellular heterogeneity and plasticity represent fundamental obstacles to effective therapies. Understanding the determinants that govern glioma cell diversity and adaptability is critical to overcoming treatment resistance. Recent single cell DNA methylation studies have demonstrated that dynamic epigenetic alterations facilitate glioma cell state shifts and stress response. However, information regarding other modes of epigenetic gene regulation, such as chromatin accessibility, and how therapy shapes cellular heterogeneity remains limited. To determine the critical regulators of glioma cell state plasticity under treatment, we profiled 36 tumors (n = 23 adult patients) with joint single nucleus RNA and ATACseq including 13 longitudinal initial – recurrent pairs that yielded a total of 79,945 cells (37,883 malignant cells). We identified chromatin peaks that were uniquely open in glioma cells (n = 14,462 peaks, FDR < 0.05) compared with tumor microenvironmental cells including neuronal, perivascular, glial, and immune populations. Among malignant cells, differentiated-like cells exhibited more recurrent regions of accessibility than stem-like cells. These populations could be further delineated by differential peak enrichment of transcription factor binding sites in the stem-like (TCF12, ASCL1), differentiated-like (SMARCC1, JUN), and proliferating stem-like (E2F4) malignant cells nominating these transcription factors as master regulators. We confirmed that these cell state-specific open chromatin peaks overlapped enhancer regions via single nucleus multiomics and bulk H3K27ac profiling in 3 patient-derived cell lines. We further demonstrated that there are cell state-specific chromatin changes at recurrence with a trend toward a more open chromatin state that was associated with coordinated transcriptional changes. Finally, we incorporated matched longitudinal whole genome sequencing data to evaluate mutational profiles and differentiate between predominantly epigenetically driven changes and epigenomic co-evolution with the genome. Together, these findings define the key epigenetic switches that shape glioma cell states and facilitate plasticity during tumor progression.
EPCO-19. ADAPTIVE RESPONSES TO GENOME-WIDE DNA DAMAGE RESULT IN TOPOLOGIC GENOME REORGANIZATION IN GLIOBLASTOMA
Authors: Modrek Aram , Do Catherine , Zhang Zeyan , Deng Yingwen , Karp Jerome , Ezhilarasan Ravesanker , Valor Belen , Cova Giulia , Jafari Matiar , Snuderl Matija , Tsirigos Aristotelis , Skok Jane , Sulman Erik
Published: November 2022

In glioblastoma, treatment with radiation and chemotherapy leads to DNA-damage and most DNA breaks are faithfully repaired, but the impact on the epigenome is largely unknown. Using newly developed tools to enable these studies, we hypothesize that genome-wide DNA damage leads to local alterations in DNA-methylation, genome organization, and results in persistent gene-expression alterations near sites of repaired damage. We use patient-derived human glioblastoma stem-like cells (GSCs) as a model. DNA breaks are induced using (i) irradiation or (ii) a novel “multi-cut” CRISPR-Cas9 DNA break system followed by multi-omic profiling. With radiation, we find significant and wide-spread alterations in DNA-methylation after treating multiple glioblastoma cultures. However, it is challenging to study local alterations around sites of radiation induced damage because breaks are introduced at different sites in each cell, resulting in stochastic DNA methylation alterations. To circumvent this issue, we developed a multi-cut CRISPR-Cas9 DNA break system that targets 142 or 483 pre-defined loci. Induction of pre-mapped genome-wide cuts reproduces a similar level of toxicity as standard doses of radiation. To assess repair efficiency and confirm induction of breaks, we performed targeted sequencing of the 142 or 483 sites to allow for high coverage sequencing. To understand how DNA damage may lead to regional epigenetic and 3D chromatin organization changes, we performed HiC, Methylation-seq, ChIP-seq of the chromatin organizing factor CTCF and enhancer marker H3K27ac, as well as RNA-seq, before and after cut induction. Our findings show significant mega-base scale alterations in chromatin contacts centered around cut sites, enrichment of DNA methylation alterations at regulatory elements and altered gene-expression. The findings here provide a mechanistic view of the interplay between genome-wide DNA damage, DNA methylation and genome re-organization, and have wide ranging implications for the effect of DNA damage on the epigenome in glioblastoma.
EPCO-20. EXPLORATION OF DNA METHYLATION PATTERNS IN GLIOBLASTOMA REPROGRAMMED MICROGLIAL CELLS
Authors: Richart Lorraine , Cialini Camille , Heurtaux Tony , Müller Tanja , Hau Ann-Christin , Mittelbronn Michel
Published: November 2022

Glioblastoma (GBM) is the most frequent and malignant adult-type diffuse glioma (WHO grade IV) with a median patient survival of less than 15 months despite multimodal treatment. The poor prognosis of GBM, among others, is associated with a tumor-supporting microenvironment characterized by a rather anti-inflammatory state, where the tumor cells have been shown to hijack microglial gene expression profiles. These so-called tumor-associated microglia cells (TAMs) repress normal immune functions, such as phagocytosis and pro-inflammatory cytokine secretion through transcriptional reprogramming, further underlying morphological changes. It is currently starting to emerge that the exceptional cellular plasticity required to orchestrate such microglial reactivity could originate from pre-imposed epigenetic modifications. We thus hypothesize that TAM reprogramming in GBM is controlled by epigenetic mechanisms, and therefore aim to understand if modifications in DNA methylation patterns can lead to pro-tumor transcriptomic and phenotypical changes.Reactive microglia are classically described as either ‘pro-inflammatory’ M1 or ‘anti-inflammatory’ M2 phenotypes, inducable by Lipopolysaccharide (LPS) and Interferon-gamma (IFNɣ) or Interleukin-4 (IL-4), respectively. In a GBM context, microglial cells have been mostly classified as M2, but exhibit heterogeneous features among the M1 to M2 activation spectrum. In this study, we exposed human and murine microglial cell lines to LPS, IFNɣ, IL-4, and GBM-conditioned medium (GBM-CM), followed by morphological assessment, transcript expression and secretome characterization. The onset of activation was followed in time series every 12h to interrogate epigenetic and transcriptomic changes together with protein expression and secretion. After exposure to GBM-CM, microglial cells exhibited a bipolar and more elongated phenotype. We observed significant variations in cytokine production together with a decrease in phagocytosis in LPS-treated microglia, whereas the secretome in GBM-CM was only slightly altered. We furthermore observed differentially methylated regions (DMRs) using the novel Infinium® Mouse Methylation BeadChip, suggesting a role of DNA methylation in microglial reprogramming.
EPCO-22. SINGLE CELL ANALYSIS TO UNDERSTAND SEX DIFFERENCES IN GBM OUTCOME
Authors: Llaci Lorida , Rubin Joshua , Mitra Rob
Published: November 2022

Males have a higher incidence and mortality in certain cancers compared to females. The same is true in glioblastoma (GBM) regardless of age, suggesting that cell-intrinsic factors rather than extrinsic factors such as circulating sex hormones are causing these sex differences. Our lab has demonstrated cell-intrinsic sex differences with respect to growth, clonogenicity, and in vivo tumorigenesis using an isogenic murine astrocyte cell culture model of GBM (Nf1 -/-; DNp53). Male astrocytes are more likely to adapt and grow when exposed to irradiation-induced stress compared to female astrocytes, which are more likely to undergo growth arrest after the same exposures. These sex differences in response to treatment can be explained by the different chromatin and transcriptional profiles established from the moment of fertilization that can result in different levels of transcriptional heterogeneity, a well-established cause for resistance to induced stress in GBM. However, so far sex has not been considered when exploring transcriptional heterogeneity. As such, we used 10x Genomics technology to extract single nuclei RNA (snRNA) and ATAC (snATAC) sequencing from the same nuclei and identified different levels of transcriptional heterogeneity in male and female astrocytes cells from our model. We also identified different chromatin profiles of crucial genes, such as Sox2, an important TF for the reprogramming of differentiated GBM into stem-like cells, which can then form tumors in vivo. We expect for the male astrocytes to be more effective in escaping growth arrest and adapting to irradiation-induced stress because of these different transcriptional and chromatin profiles. Our work will identify epigenetic mechanisms by which male cells are more able to adapt to treatment-induced stress compared to female cells and will further advance our understanding of sex differences in treatment-response in GBM and cancer overall, while giving avenues for the development of novel treatments.
EPCO-25. MULTI-OMIC ANALYSIS OF THE GLIOBLASTOMA EPIGENOME AND TRANSCRIPTOME INFORMS OF MIGRATORY INTERNEURON-LIKE DEVELOPMENTAL REGULATORS
Authors: Ramos Susana Isabel , Mussa Zarmeen , Giotti Bruno , Tsankov Alexander , Tsankova Nadejda
Published: November 2022

Recent studies have demonstrated that, despite their nomenclature, gliomas recapitulate an interneuron progenitor-like state that drives tumor progression. During human neurodevelopment, interneurons arise from the subcortical ganglionic eminences and migrate tangentially into the neocortex, settling in the cortical plate where they integrate local neurocircuitry. Analogously, malignant glioblastoma (GBM) cells migrate from the tumor core into the surrounding healthy tissue. This innate infiltrative property renders these malignant cells elusive to surgical resection, leading to tumor recurrence. To understand the regulatory networks that drive tumor infiltration from a neurodevelopmental perspective, we generated a single-nucleus Assay for Transposase-Accessible Chromatin sequencing (snATAC-seq) dataset of 41,000 nuclei from the core and infiltrative edge of surgically resected GBM specimens (n = 4). Concurrently, we sequenced 46,000 nuclei from non-pathological, postmortem samples of second- and third-trimester neocortices (n = 17). We integrated these datasets with paired single-nucleus RNA sequencing (snRNA-seq) data and identified candidate regulatory TFs that exhibit high correlation between motif enrichment and TF expression. Using single-trajectory inference and pseudo-time analyses, we identified TCF12 as a potential driver of interneuron lineage fate in developing cortical progenitors. Given its implication in projection neuron migration, we were intrigued to find that TCF12 activity is highest in GBM cells with a migratory interneuron signature, hinting at its putative role in tumor infiltration. To understand the significance of these findings, we will interrogate other genes in the TCF12 regulatory network with the ultimate goal of identifying therapeutic targets that inhibit GBM infiltration.