bluuebunny/crossref_metadata_2025 huggingface dataset:
QOL-17. SLEEP QUALITY DIMENSIONS IN LOW AND HIGH-GRADE GLIOMA SURVIVORS
Authors: Chen Erica , Wang Chencai , Wall Lucy , Cho Nicholas , Ellingson Benjamin , Cloughesy Timothy , Lai Albert , Chong Robert , Van Dyk Kathleen , Nghiemphu Phioanh
Published: November 2023

In this study, we examined the relationship between sleep disturbance and tumor grades in a group of low-grade (LGG; grade I-II) and high-grade glioma (HGG; grade III-IV) survivors < 1 to 10+ years from initial diagnosis. 42 glioma survivors completed the Pittsburgh Sleep Quality Index (PSQI). We examined frequency of poor sleep quality (defined as PSQI >5) and compared global PSQI between LGG and HGG groups. We obtained high-resolution T1 weighted images from a subset of 24 patients for gray matter volume analyses. The sample was predominantly male (66%) and Caucasian (82%). Of the 42 participants, 31% (n = 13) had LGG and 69% (n = 29) had HGG. 60% (n = 25) of all participants had poor sleep quality, with no differences observed between LGG and HGG. There were no differences between groups in age, education, measures of depression and anxiety, or general health-related quality of life (MOS SF-36). A Mann-Whitney U test indicated that there was no significant difference in global PSQI scores between LGG (Mdn = 4) and HGG groups (Mdn = 6), U = 239, p = .254. Sleep quality was not associated with time since diagnosis for either LGG (r = .108, p = .724) and HGG groups (r=-.058, p = .762). Whole brain vertex-wise comparison revealed smaller gray matter volumes in patients with poor sleep quality versus good sleep quality in the isthmus cingulate, cuneus, and precuneus of the left hemisphere (p < 0.05). Our analyses suggest that sleep quality is important to assess in glioma survivors of any grade and at any time since diagnosis. Poor sleep in glioma survivorship could be associated with structural differences in brain regions sensitive to sleep problems in other populations. Given the high rate of sleep disturbance, further study is warranted to better understand risk and develop targeted interventions.
QOL-20. INCLUDING BRAIN METASTASES PATIENTS IN PSYCHOLOGICAL INTERVENTIONS: A PHASE II SINGLE-ARM INVESTIGATION OF MANAGING CANCER AND LIVING MEANINGFULLY
Authors: Loughan Ashlee , Lanoye Autumn , Davies Alexandria , Willis Kelcie , Braun Sarah , Kleva Chris , Fox Amber , Zarrella Giuliana , Rodin Gary
Published: November 2023

BACKGROUND

Patients with brain cancer demonstrate substantial psychological distress yet are frequently excluded from psychological research. Managing Cancer and Living Meaningfully (CALM), an expressive-supportive psychotherapy designed to address the challenges faced by patients with advanced cancer. CALM is proven to reduce depression and death-related distress; however, patients with brain metastases (bMETs) have not been formally examined for CALM’s appropriateness or effectiveness.

METHODS

In this ongoing Phase II trial, 15 adults with bMETs and heightened distress (PHQ/DADDS) participate in a six-session CALM intervention and complete intervention satisfaction surveys and interviews. Data collection includes established feasibility and acceptability metrics, intervention satisfaction surveys and interviews, and changes in distress patient reported outcomes (pre-to-post CALM).

RESULTS

Of 21 patients screened, 15 enrolled in the study (73% female; 80% White; Mage = 58yrs). All 15 bMET participants completed baseline assessments, with 13 trial initiators, and 2 screen fails. To date, 8 participants have completed treatment. Reasons for withdrawal include disinterest in intervention topics (n = 1) and lost to follow-up (n = 2). Retention is 73%, with 2 participants still in active treatment. No adverse events were determined to be study-related. Perceived benefit was high (4.3/5), and all participants reported they would recommend the program to others. Reductions in depression severity were demonstrated in 6 of 8 completed participants (MPHQ Reduction = 7.6, range = 2-11) and in death anxiety severity for 7 of 8 completed participants (MDADDS-F1 Reduction = 14.7, range = 6-23).

CONCLUSIONS

Preliminary data suggests that CALM is both feasible and acceptable among adult patients with bMETs. Enrollment and retention rates are adequate. Patients report high benefit and recommendation to others. Overall, depression and death-related distress severity scores improved, suggesting CALM may be a promising intervention for neuro-oncology patients as they navigate the challenges of metastatic brain cancer. These findings support advancement to the next stage, a Phase II pilot RCT.
RBIO-02. NOVEL, QUIESCENT SUBPOPULATION EMERGES AFTER LOW-DOSE IRRADIATION OF GLIOMA STEM CELLS
Authors: Lewis Erika , Cascio Costanza Lo , McNamara James , Mehta Shwetal , Plaisier Christopher
Published: November 2023

Glioblastoma (GBM) tumors contain a subset of highly radiation resistant cells referred to as glioma stem cells (GSCs). We used single-cell RNA-seq (scRNA-seq) to characterize the transcriptional states that increase in size following GSC irradiation to further our understanding of the acute responses to radiotherapy. We treated two GBM patient-derived xenograft-derived GSC lines to low-dose irradiation (4 Gy). We then conducted scRNA-seq before irradiation and three days and one-week post-irradiation. As expected, the number of GSCs undergoing division through the cell cycle was drastically reduced relative to control conditions, and a subpopulation of GSCs with DNA damage response markers emerged after irradiation. Interestingly, we observed a novel, distinct subpopulation that was common between GSC lines, expanded after irradiation, and featured marker genes related to cell cycle arrest in response to external stressors. Gene regulatory network analysis identified transcription factors (TFs) likely to regulate these marker genes and potentially the dynamics of this subpopulation. The TFs were also related to cell cycle suppression and the overall expression state of these cells was similar to the quiescent Neural G0 state, indicating that our novel subpopulation may contain quiescent GSCs. In upcoming studies, we plan to perturb these TFs and marker genes to determine the importance of these genes in the GSC response to irradiation. Further exploration of this novel quiescent subpopulation may lead to new druggable targets that sensitize GBM tumors to radiotherapy.
RBIO-05. MITOTIC ENRICHMENT AS AN EFFICIENT RADIOSENSITIZATION STRATEGY FOR INTRACRANIAL TUMORS
Authors: de Gooijer Mark , Colakoglu Hilal , Citirikkaya Ceren , Fedorushkova Daria , El Ouazani Amal , Shah Ronak , Meel Michael , Hulleman Esther , Borst Gerben , van Tellingen Olaf
Published: November 2023

Radiotherapy remains one of the most effective modalities for anticancer treatment and part of standard of care for many primary and metastatic brain tumors. Boosting the efficacy of radiotherapy is therefore a logical avenue to improve patient survival. We have developed a radiosensitization strategy called ‘induction of mitotic enrichment’. It has long been known that the radiosensitivity of a cell depends on the phase of the cell cycle and that mitotic cells are especially vulnerable. Enriching the tumor for mitotic cells by arresting them during division prior to each radiotherapy fraction should therefore render the tumor population more sensitive to irradiation. Ideally, induction of mitotic enrichment should be reversible and non-cytotoxic to prevent healthy tissue toxicity and be compatible with clinically applied fractionated radiotherapy regimens. We have now identified an orally available targeted tubulin polymerization inhibitor that can achieve repeated and reversible mitotic enrichment for up to 10 hours prior to radiotherapy, without causing cytotoxicity in vitro or healthy tissue toxicity in vivo. This tubulin inhibitor (ABT-751) efficiently radiosensitizes a range of preclinical tumor models representing adult and pediatric, primary and metastatic brain tumors. Importantly, ABT-751 also improves survival in mouse models of adult glioblastoma (GBM), but only in a mitotic enrichment setup when given several hours prior to radiotherapy to allow accumulation in mitosis. Of note, induction of mitotic enrichment does not exacerbate healthy tissue toxicity. To conclude, induction of mitotic enrichment by ABT-751 radiosensitizes adult GBM to fractionated radiotherapy. We are currently expanding our preclinical development of mitotic enrichment as a radiosensitization strategy to other targets and cancers and have designed a phase 0/I trial for adult GBM to demonstrate induction of mitotic enrichment and tolerability when combined with radiotherapy. We expect to start enrollment in this trial soon.
RTID-03. A PHASE 1/2 STUDY OF THE WEE1 INHIBITOR DEBIO 0123 IN COMBINATION WITH TEMOZOLOMIDE +- RADIOTHERAPY IN ADULTS WITH RECURRENT OR NEWLY DIAGNOSED GLIOBLASTOMA
Authors: Roth Patrick , Papadopoulos Kyriakos P , Vieito Maria , Yang Jonathan , Majd Nazanin , Sepúlveda Juan , Schaff Lauren , Moreno Victor , Pérez -Larraya Jaime Gállego , Micallef Sandrine , Bellon Anne , Omar Mokhtar , Imedio Esteban Rodrigo , Piggott Luke , Rodriguez-Freixinos Victor , Rodon Jordi
Published: November 2023

BACKGROUND: Debio 0123 is an oral, brain-penetrant, highly selective WEE1 inhibitor. WEE1 inhibition leads to S phase and G2/M cell cycle checkpoint abrogation, permitting mitosis without DNA repair, leading to mitotic catastrophe and subsequent cell death. Preclinically, Debio 0123 has been shown to effectively penetrate the brain and demonstrated improved response to radiotherapy (RT) in vitro and temozolomide (TMZ) in mouse models of GBM, supporting the clinical investigation of Debio 0123 with TMZ +/- RT. Trial design: This Phase 1/2 multi-center study (NCT05765812) is evaluating Debio 0123 in combination with TMZ in patients (pts) with recurrent GBM isocitrate dehydrogenase (IDH)-wildtype (WT) or astrocytoma, IDH-mutant, Grade 3 (per WHO 2021 criteria) after first-line, TMZ-based chemoradiotherapy (CxRT) (Phase 1 Arm A) and Debio 0123 combined with TMZ-based CxRT in pts with newly diagnosed GBM IDH-WT (Phase 1 Arm B). In Arm A, pts will receive escalating doses of Debio 0123 with TMZ in 28-day cycles supported by a Bayesian logistic regression model (BLRM). Arm B is a Debio 0123 dose escalation with concomitant TMZ/RT for up to 6 weeks. The primary objective of both Phase 1 arms is to identify the recommended Phase 2 dose (RP2D). Secondary objectives include safety, pharmacokinetics, and preliminary antitumor activity. Key inclusion criteria are ≤2 prior treatment lines (only 1 systemic line allowed) and Karnofsky Performance Status (KPS) ≥60 (Phase 1 Arm A). In Phase 1 Arm B, pts with KPS ≥70 who are eligible for standard TMZ-based CxRT will be included. Phase 2 will be an externally controlled, open-label study comparing the efficacy (overall survival) of Debio 0123 combined with TMZ at the Phase 1 Arm A RP2D vs. standard of care in pts with recurrent GBM IDH-WT. The control arm will include patient-level data from recently completed clinical trials. Accrual is currently ongoing.
RTID-08. A RANDOMIZED, MULTICENTER, DOUBLE-BLIND, PHASE 2B STUDY OF IGV-001, AN AUTOLOGOUS CELL IMMUNOTHERAPY WITH ANTISENSE OLIGO IMV-001 TARGETING IGF-1R, VS PLACEBO, IN NEWLY DIAGNOSED GLIOBLASTOMA PATIENTS
Authors: Lee Ian , Judy Kevin , Schulder Michael , Hanft Simon , Evans Linton , Wu Julian , Aulakh Sonikpreet , Wong Eric , Agarwal Vijay , Ramakrishna Rohan , Elder J Bradley , Gill Brian , Quiñones-Hinojosa Alfredo , Brennan Cameron , Perez-Olle Raul , Diwanji Madhavi , Pennock Gregory , Scott Charles , Andrews David , Boockvar John
Published: November 2023

Glioblastoma (GBM) is the most common primary brain malignancy in adults. Standard of care (SOC) for suspected GBM begins with maximal safe resection followed by adjuvant radiotherapy and temozolomide, and maintenance temozolomide. Imvax has developed the Goldspire™ platform to create IGV-001, an autologous biologic-device combination product for the treatment of newly diagnosed GBM (ndGBM). IGV-001 consists of autologous GBM tumor cells and an antisense oligonucleotide against IGF-1R mRNA (IMV-001), irradiated and administered via biodiffusion chambers implanted in the abdomen. Together, these components stimulate immunogenic cell death and antigen release. IGV-001 was well tolerated and multiple efficacy signals were observed in a Phase 1b study in patients with ndGBM, including significant improvements in progression-free survival (PFS), radiographic evidence of tumor response, and changes in immune response biomarkers. A Phase 2b randomized, multicenter, double-blind, placebo-controlled study has been initiated to assess the safety and efficacy of IGV-001 in patients with ndGBM (NCT04485949). After surgical resection, patients will be treated with IGV-001 or placebo followed by SOC. 25 US sites have been selected with a target enrollment of 93 patients (2:1 randomization) and the study is open to enrollment. Key inclusion criteria are 18 to 70 years of age, Karnofsky performance status score ≥ 70, diagnosis of GBM based on the treating neurosurgeon's best clinical judgement, confirmed measurable disease pre-operatively, tumor located in the supratentorial compartment, and adequate bone marrow and organ function. Key exclusion criteria include bihemispheric disease, multicentric disease, or treatment with Tumor Treating Fields prior to documented progression. The primary outcome is PFS, defined as the time from randomization to first progression, as determined by blinded central radiology review, or death. Secondary outcomes include overall survival, defined as the time from randomization to death due to any cause, and safety.
SURG-20. USEFULNESS OF PHOTODYNAMIC THERAPY (PDT) WITH TALAPORFIN SODIUM FOR GLIOBLASTOMA
Authors: Sasayama Takashi , Tanaka Kazuhiro , Nagashima Hiroaki , Fujita Yuichi , Yamanishi Shunsuke
Published: November 2023

BACKGROUND

Photodynamic therapy (PDT) with talaporfin sodium uses the toxicity of singlet oxygen generated by a reaction between a photosensitizer in tumor cells and light with a specific wavelength. PDT was introduced in our hospital in April 2017. We retrospectively analyzed the glioblastoma (GBM) patients treated with PDT and compared with the patients who did not receive PDT.

MATERIAL AND METHODS

From April 2015 to March 2023, total 145 patients with GBM were treated in our hospital. Among them, patients of recurrence, IDH mutant, biopsy and no chemo/radiotherapy were excluded. The patients’ characteristics, adverse event, changes of the MR image, recurrence pattern, outcome of the patients were analyzed. In addition, survival time of the patients between the PDT group and the non-PDT group was compared.

RESULTS

A total of 80 GBM patients were analyzed. Forty-four patients received PDT. 4 patients had adverse event; cyst formation, venous infarction, brain swelling, and delirium. In most of the patients, linear high signals of 5-7 mm on DWI were detected at the surface of the resected cavity and matched the PDT-irradiated area from 1 day after PDT. All hyperintense signal on DWI disappeared in about 30 days without any neurological deterioration. Sixty-seven patients had recurrence (PDT group; 33 cases, non-PDT group; 34 cases). Recurrence pattern of distant/dissemination were significantly increased in the PDT group compared with the non-PDT group. The PDT group tended to have longer survival in both OS (p = 0.08) and PFS(p = 0.07) than the non-PDT group. In multivariate analysis for OS, age and MGMT promotor methylation were significant prognostic factors, but not PDT.

CONCLUSION

PDT was safety and useful for GBM. However, the PDT group had significantly more distant/disseminated recurrences than the non-PDT group. We need to analyze more cases to clarify efficacy and recurrence patterns.
SURG-22. MECHANISMS OF BBB PERMEABILITY CHANGES TRIGGERED BY LASER THERAPY
Authors: Cleary Ryan , Kim Albert
Published: November 2023

The blood-brain barrier (BBB) severely limits access of systemically delivered drugs to the brain and brain tumors. Laser interstitial thermal therapy (LITT) has previously been shown to increase BBB permeability in both patients and in mice. The exact mechanisms of LITT-induced BBB permeability changes and their temporal features have yet to be elucidated. To answer this question, we used an established mouse model of LITT to evaluate changes in endothelial cell tight junction integrity and transcytosis over time in normal brain and demonstrate changes in transcytosis in human GBM tumor samples. Mean vesicular density (MVD) was calculated using electron microscopy to evaluate transcytosis. Immunohistochemistry (IHC) was used to assess tight junction integrity (Claudin 5 area/CD31 area) and Mfsd2a levels (Mfsd2a area/CD31 area) along endothelial cells in the laser penumbra. Tight junction integrity decreased 2.5 fold 3 days after LITT, with continued decrease 14 days post-LITT. Mean vesicular density (MVD) in endothelial cells within the laser penumbra increased 3-4 fold compared to sham treated mice, with a peak increase 14 days after LITT before returning to baseline levels 21 days after treatment. These changes in transcytosis correlated with a significant decrease in the intensity of Mfsd2a IHC in the laser penumbra at day 14. Finally, we found similar low levels of transcytosis in non-enhancing and enhancing human GBM tumor samples, confirming that transcytosis is potentially targetable to manipulate BBB permeability. CONCLUSION: Disruptions in tight junction integrity continue up to 14 days after LITT, while LITT-induced increases in transcytosis occur in a delayed fashion, peaking 14 days after laser treatment. Increased transcytosis is inversely correlated with decreased Mfsd2a expression, suggesting a role for Mfsd2a in regulation of LITT-induced BBB changes. Importantly, baseline levels of transcytosis in human GBM appear to be low, such that transcytosis could be targeted to increase BBB permeability.
SURG-32. EFFICACY OF LASER INTERSTITIAL THERMAL THERAPY (LITT) FOR BIOPSY-PROVEN RADIATION NECROSIS IN RADIOGRAPHICALLY RECURRENT BRAIN METASTASES
Authors: Strowd Roy , Chan Michael , Tatter Steven , Chiang Veronica , Fecci Peter , Prabhu Sujit , Hadjipanayis Constantinos , Kirkpatrick John , Sun David , Sinicrope Kaylyn , Mohammadi Alireza , Sevak Parag , Abram Steven , Kim Albert , Leuthardt Eric , Chao Samuel , Phillips John , Lacroix Michel , Williams Brian , Placantonakis Dimitris , Silverman Joshua , Baumgartner James , Piccioni David , Laxton Adrian
Published: November 2023

BACKGROUND

Evidence is growing for the efficacy of laser interstitial thermal therapy (LITT) for radiation necrosis (RN) following stereotactic radiosurgery (SRS) for patients with brain metastases. Questions remain regarding local control, symptom control, and concurrent use of therapies.

METHODS

Demographics, intraprocedural data, safety, Karnofsky performance status (KPS) and survival data were prospectively collected from the LAANTERN multi-center registry (NCT02392078) then analyzed on patients consented between 2016-2020 and who were undergoing LITT for biopsy-proven RN at one of 14 U.S. centers. Data was monitored for accuracy. Statistical analysis included individual variable summaries, multivariable Fine and Gray analysis, and Kaplan Meier estimated survival.

RESULTS

Ninety patients met inclusion criteria. Median hospitalization time was 32.5hrs. Median time to corticosteroid cessation after LITT was 13 days (range 0 - 1229) and cumulative incidence of lesional progression was 19% at 1-year. Median post-procedure overall-survival was 2.6 years [1.7, NR] and 77% at one year as estimated by Kaplan Meier. Median KPS remained 80 through 2-year follow-up. Seizure prevalence improved from 34.4% pre-procedure to 12% 1-month post-LITT and 7.9% at 3-months. There was no significant difference in risk of radiographic progression in total and near-total ablations (91% or greater ablative coverage) versus sub-total ablations (< 90%). Lesion size was not a significant predictor of future radiographic progression.

CONCLUSIONS

LITT is an effective, minimally invasive, safe treatment for RN, in terms of both local control and symptom management. LITT is effective in the management of lesion-related seizures in addition to averting expected neurological death. LITT facilitates ongoing systemic therapy (particularly immunotherapy) by enabling the rapid cessation of corticosteroids. Effective management options for RN could facilitate the more aggressive use of combined systemic and radiotherapeutic treatment options for brain metastases patients in order to avoid failure due to tumor recurrence and extend survival.
SURG-46. PRIMARY MALIGNANT MELANOMA, AN ATYPICAL PRESENTATION IN THE CERVICAL SPINE
Authors: Kamabu Larrey , Kataka Louange Maha , Galukande Moses , Lekuya Hervé Monka
Published: November 2023

Few studies have documented the occurrences of melanomas in the cervical spine. one percent of all malignant melanoma cases are primary melanoma of the central nervous system, which is extremely uncommon and nonspecific. We aimed to report a case of uncommon presentation of primary melanoma in the cervical spine. This a 59-year-old, male who presented with a 2-year history of anterior neck swelling, severe pain and tingling sensation in the left shoulder and arm which worsened in the previous 6 months. He developed weakness and paresthesia in the left upper arm and progressive gait disturbance of the left lower limb. Physical examination revealed masses in the left cervical and right submandibular region. There was left upper and lower extremities hemiparesis and hemi hypoesthesia. MRI showed hyperintense lesion on T1WI and hypointense on T2WI originating from the cervical spine and involving the vertebral bodies and paravertebral soft tissues. The patient underwent surgery, a black tumor was extracted, and histology revealed malignant melanoma. This case is presented in order to highlight the significance of and challenges associated with making a preoperative diagnosis of primary cervical melanoma with atypical radiological characteristics. Patients with extradural lesions that show hyperintensity on T1 weighted images and hypo intensity on T2-weighted images should have spinal melanoma examined as a possible differential diagnosis.
TMET-07. METABOLIC RISK FACTORS AND OUTCOMES IN PATIENTS WITH GLIOBLASTOMA
Authors: Aboubechara John Paul , Aboud Orwa
Published: November 2023

A growing body of evidence is beginning to implicate mutations in genes underlying cellular metabolism in the etiology of glioblastoma. The metabolic syndrome has been found to increase the risk of developing various systemic cancers, but it is not known how often the metabolic syndrome occurs in patients with glioblastoma or how it affects their clinical outcomes. Therefore, the purpose of this study is to test the hypothesis that the metabolic syndrome is a risk factor for developing glioblastoma and is associated with worse survival outcomes. A retrospective cohort study was conducted, consisting of patients at a single institution. Clinical records from 40 patients with glioblastoma IDH wild type were reviewed as part of this interim analysis—with plans to analyze 80 patients by study completion. Records included the patient’s diagnosis, progression free survival, overall survival, treatment, tumor molecular characteristics, blood pressure, body mass index, medications, and laboratory data. Our results demonstrate a trend that patients with the metabolic syndrome have worse overall survival compared to those who do not (16.7 months vs 8.1 months; p=0.069). Interestingly, hypertension (p=0.007), hyperglycemia (p = 0.044), and dyslipidemia (p = 0.041) were negatively associated with survival, while BMI was not. Furthermore, there was a significant negative association between overall survival and the number of metabolic risk factors that patients accumulate (i.e. BMI, HTN, etc.) (p=0.0038). However, our results demonstrate the prevalence of metabolic syndrome in GBM patients to be 30%, which is less than that of the general population, 35%. These interim results suggest that the metabolic syndrome is associated with worse survival in patients with glioblastoma IDH wild type, but that it is not a risk factor in the development of this cancer. These results support other work that has implicated metabolic dysregulation in the pathogenesis of glioblastoma.
TMET-08. ELONGATION CONTROL OF MRNA TRANSLATION DRIVES GROUP 3 MEDULLOBLASTOMA ADAPTATION TO NUTRIENT DEPRIVATION
Authors: Delaidelli Alberto , Yao Betty , Burwag Fares , de Santis Jessica Oliveira , Huang Yue Zhou , Zhang Haifeng , Negri Gian Luca , Hughes Christopher , Leprivier Gabriel , Sorensen Poul
Published: November 2023

Group 3 affiliation and MYC genetic amplification are associated with poor life expectancy and substantial morbidity in children suffering from medulloblastoma (MB). However, the high metabolic demand induced by MYC-driven transformation sensitizes MYC-overexpressing MB to cell death under conditions of nutrient deprivation (ND). Additionally, MYC-driven transformation is known to promote mitochondrial oxidative phosphorylation (OXPHOS). We previously reported that eukaryotic Elongation Factor Kinase 2 (eEF2K), the master regulator of mRNA translation elongation, promotes survival of MYC-overexpressing tumors under ND. Interestingly, eEF2K is overexpressed in MYC-driven MB and our preliminary proteomics data highlight large-scale alterations in OXPHOS components affecting eEF2K deficient MB cells. We therefore hypothesized that eEF2K activity is required for the selective translation of mRNAs needed for efficient OXPHOS, and for the progression of MYC-driven MB. We performed Multiplexed enhanced Protein Dynamic Mass Spectrometry in eEF2K knockdown MYC-overexpressing D425 MB cells to identify mRNAs selectively translated upon eEF2K activation. Messenger RNAs encoding multiple (9 out of 10 detected) components of the mitochondrial OXPHOS pathway are selectively translated upon eEF2K activation. Inactivation of eEF2K by genetic KO leads to the disassembly of electron transport chain (ETC) complexes I-IV without affecting mRNA levels of their respective components. Consistently, eEF2K KO MB cells display decreased mitochondrial membrane potential and 20% increased proton leak thorough the mitochondrial membrane. In addition, eEF2K inactivation results in increased Group 3 MB cell death under ND and doubles survival of MB bearing mice fed with calorie restricted diets (p< 0.05). Control of mRNA translation elongation by eEF2K is critical for mitochondrial ETC complex assembly and efficient OXPHOS in MYC-overexpressing MB, likely representing an adaptive response by which MYC-driven MB cells cope with acute metabolic stress. Future therapeutic studies will aim to combine eEF2K inhibition with caloric restriction mimetic drugs as eEF2K activity appears critical under metabolic stress conditions.
TMET-14. PROBING TCA CYCLE ACTIVITY IN H3WT AND H3K27M-ALTERED DIFFUSE MIDLINE GLIOMAS
Authors: Ijare Omkar , Roberson Jackson , Kumar Sushmita , Ramamurthy Rishith , Baskin David S , Pichumani Kumar
Published: November 2023

DMG has high levels of α-ketoglutarate (α-KG), causing histone hypomethylation and promoting tumor growth. Therefore, targeting α-KG production in DMG tumors may be of therapeutic value. α-KG is synthesized in the tricarboxylic acid cycle (TCA) cycle via oxidation of multiple nutrients including glucose and glutamine. Hence, probing mitochondrial metabolism in DMG with the goal of altering α-KG levels will lead to new therapies to treat DMG. Here, we examine glucose and glutamine metabolism in H3WT and H3K27M-altered patient-derived DMG cells (Dr. Monje’s lab) using GC-MS based metabolic flux analysis. Both cells were grown as neurospheres in tumor stem medium. Neurospheres were treated with 11.0 mM [U-13C]glucose or 4.0 mM [U-13C]glutamine. The 13C-isotopomer analysis revealed that H3K27M-altered cells produced higher levels of (M+3) pyruvate (14.05 ± 5.37% vs. 7.15 ± 2.98%), and (M+3) lactate (9.46 ± 6.48 % vs.3.87 ± 1.80 %) compared to the H3WT. Whereas, the glucose derived (M+2) citrate in the TCA cycle was similar in both cases (15.81 ± 2.91% vs. 16.76 ± 4.15%). This data shows that both types of DMG possess similar TCA cycle activity leading to the synthesis of α-KG, which we measured through glutamate 13C labeling. Next, we probed [U-13C]glutamine metabolism in these two types of DMG cells as glutamine is another major source of α-KG synthesis . Both cell lines showed higher levels of glutamine-derived M+5 α-KG (34.62 ± 2.12 % vs. 42.17 ± 5.05%). Interestingly, H3K27M-altered DMG showed higher flux via reductive carboxylation generating M+5 citrate when compared to M+4 citrate produced via canonical glutamine metabolism in the TCA cycle (citrate M+5: 7.13 ± 2.14% vs. 4.33 ± 1.68%; citrate M+4: 4.04 ± 1.06% vs. 7.85 ± 1.52%). Therefore, inhibiting synthesis of α-KG in H3 K27M-altered DMGs would be of therapeutic interest in the treatment of both DMG subtypes.
TMIC-12. RAB27 REGULATION OF VASCULAR WALL INTEGRITY MEDIATES T-CELL INFILTERATION IN GLIOBLASTOMA
Authors: Adnani Lata , Meehan Brian , Rak Janusz
Published: November 2023

Endothelial secretome exerts a potent influence on the phenotype of cancer cells and immune microenvironment. Recently, we have reported that glioblastoma stem cells acquire a more aggressive mesenchymal state under influence of vascular endothelial cell derived extracellular vesicles (EVs). Since Rab27, GTPases involved in multiple aspects of EV (exosome) biogenesis, has been implicated in control of angiogenic pathways through regulation of VEGFR1 turnover and possibly other mechanisms, we interrogated the role of Rab27 in the function of normal and glioblastoma associated brain microvasculature. Using mice with disrupted Rab27a and Rab27b isoforms, we documented that these proteins control development and stability of the brain vasculature including pathological angiogenesis in glioblastoma. Thus, relative to wild-type C57bl/6 (WT) and double heterozygous Rab27a+/-;Rab27b+/- (dHET) mice, animals with Rab27a/b double knock-out (Rab27a/b-dKO) exhibit reduced microvascular density in brain cortices. When neoangiogensis was induced following orthotopic inoculation of mouse glioma cells (GL261), multiple morphological anomalies were observed in the tumour vasculature relative to tumours established in control mice. Moreover, vascular permeability of tumours in Rab27a/b-dKO mice markedly exceeded that of similar tumours in wild type or heterozygous controls resulting in augmented T-cell infiltration into the otherwise ‘cold’ brain tumor microenvironment. Our results suggest that key switches in the cellular secretome, such as Rab27a and Rab27b, may impact endothelial membrane dynamic and intercellular interactions capabilities, whereby they may play a critical role in ensuring the stability and sustained cellular barrier function of the vasculature during brain tumour progression. Therapeutic implications of these findings are being explored.
TMIC-39. PERIVASCULAR CONTAINMENT OF T CELLS IN IDH-MUTANT ASTROCYTOMA ASSOCIATES WITH HIGH ABUNDANCE OF GEMISTOCYTIC TUMOR CELLS AND IMMUNE STIMULATORY MICROGLIA
Authors: van Hijfte Levi , Geurts Marjolein , de Heer Iris , Vallentgoed Wies , Balcioglu Emrah , Debets Reno , French Pim
Published: November 2023

Isocitrate dehydrogenase mutant (IDHmt) astrocytoma is considered a T cell-deficient tumor, yet little is known regarding the underlying mechanism that drives T cell exclusion. To this end, we have systematically characterized the IDHmt astrocytoma immune microenvironment. We used multiplex immunofluorescence stainings (n=75; 1293 regions), bulk (n=152) and single nucleus RNA-sequencing (snRNAseq) (n=8) alongside spatial proteomics and RNA sequencing (n=12; 72 regions of interest) on samples from one patient cohort from the Erasmus Medical Center in the Netherlands, enabling integrative spatially resolved multi-omics analysis. We identified three spatially distinct T cell distributions in IDHmt astrocytoma: perivascular accumulation of T cells (T cell cuffs); presence of T cells in the tumor stroma; and absence of T cells. T cells were most frequently present in cuffs. Notably, T cell cuffs were characterized by a high abundance of a histologically distinct tumor cell type called gemistocytes. Conversely, we find gemistocyte high regions to be enriched for T cell cuffs, B cells and tumor associated macrophages (TAMs). Gemistocyte high tumors have an increased expression of immune cell migration and activation programs. SnRNAseq demonstrates that these programs originate from TAMs and T cells. Interestingly, we find that gemistocytic tumor cells form a transcriptionally distinct tumor cell sub-cluster of the astrocyte-like tumor cell state that expresses CD44. Spatial transcriptomics consequently confirmed that gemistocytes co-occurred with a population of immune stimulatory microglia that expresses the CD44-ligand Secreted Phosphoprotein 1 (SPP1), the chemo-attractants CCL3, CCL4 and CCL4L2, and markers for reactive microglia. In summary, we systematically uncovered a previously unrecognized cellular network between T cells, gemistocytic tumor cells and a subpopulation of immune-stimulatory microglia. This spatially confined population of TAMs, together with gemistocytic tumor cells, harbors signatures associated with astrogliosis, a CNS-specific mechanism of T cell exclusion, and thus may explain the perivascular confinement of T cells.
TMIC-49. AUTOMATIC SEGMENTATION OF DISTINCT GLIOBLASTOMA HALLMARKS ON DIGITIZED H&E SLIDES VIA DEEP LEARNING: CURATION OF A LARGE MULTI-INSTITUTIONAL COHORT
Authors: Sandino Alvaro , Becerra David S , Sandino Nelly J , Romero Eduardo , Tiwari Pallavi
Published: November 2023

PURPOSE

Glioblastoma (GBM) is a heterogeneous brain tumor. Standard treatment constitutes surgery, chemo-radiation, and chemotherapy. After surgery, the resected tissue is analyzed under a microscope by neuropathologists to identify distinct histological hallmarks. However, visual analysis of GBM pathological features on Hematoxylin and Eosin (H&E)-stained slides is subjective, time-consuming, and more importantly, requires wide expertise. We present a hierarchical deep learning-strategy to automatically segment distinct GBM hallmarks that first distinguishes necrosis (NE) from cellular tumor (CT), and subsequently, segments regions of microvascular proliferation (MV) and pseudo-palisading cell patterns (PC) within the CT region, on digitized H&E slides.

METHODS

We employed n=541 publicly available studies including IvyGap (n=41), and TCGA (n=500). For the IvyGap cohort, expert-driven segmentations of CT, NE, MV and PC were available. We randomly employed n=21 slides from 4 patients for training, n=5 slides from 2 cases for validation, and n=2 slides from 2 cases for testing. We employed an EfficientNet model using ~600 patches of 224×224 pixels of NE and CT sampled for every slide. For semantic segmentation of MV and PC, we separately trained two EfficientNet-UNet models trained on ~200 squared-patches of 1792 and 896 pixels size, respectively.

RESULTS

Our hierarchical deep learning model on the IvyGap cohort achieved an accuracy of 96%, with an area under the curve (AUC) of 98% for distinguishing necrosis from non-necrotic (i.e. CT) regions. For segmenting PC and MV within the non-necrotic regions, our DL models achieve a dice score of 0.69 and 0.77, respectively. Additionally, the segmentation results for each of the pathological attributes were also generated and vetted for the TCGA cohort.

CONCLUSION

We developed a hierarchical model for automatic segmentation of NE, CT, and MP and PC in H&E-stained Glioblastoma images which could reduce cost, time, and effort in annotating these pathological phenotypes, for quantifying the GBM micro-environment.
TMIC-55. TURNING ENEMY INTO ALLY: HIJACK BRAIN TUMOR CELLS TO BREAK DOWN THE BLOOD-TUMOR BARRIER
Authors: Bahrampour Shahrzad , Huang Xi
Published: November 2023

A major obstacle in brain cancer treatment is the blood-tumor barrier (BTB), which limits the delivery of a vast majority of therapeutic agents. Medulloblastoma (MB), the most common pediatric malignant brain tumor, consists of four subgroups (WNT, SHH, Group 3, Group 4). Increasing BTB permeability of non-WNT MB is essential for effectively treating patients by overcoming this drug delivery impediment. Since the BTB is exposed to biofluids such as blood and brain interstitial fluid, which present dynamic osmotic challenges, we hypothesized that cell volume regulation plays a crucial role in BTB integrity. Using a genetically engineered mouse model of SHH MB, we show that tumor-specific knockout of volume-regulated ion channel, Lrrc8a, significantly increases BTB permeability and enhances the therapeutic response of MB-bearing mice to vismodegib, an FDA-approved antagonist of the SHH pathway. Lrrc8a-deficient tumor cells develop ectopic contact with blood vessels, permitting tumor cell-derived Tgfβ2 to activate Tgfβ signaling in endothelial cells. Consequently, endothelial cells in Lrrc8a knockout MB lose endothelial characteristics and gain mesenchymal features, indicative of Tgfβ signaling-induced endothelial-mesenchymal transition (EndMT). Furthermore, tumor-specific LRRC8A knockdown enhances BTB permeability in a xenograft human Group 3 MB model. Collectively, our findings establish Lrrc8a/LRRC8A as a therapeutic target to increase the therapy response of MB and provide evidence that inducing EndMT could be a strategy for enhancing BTB permeability to treat brain cancer.
TMIC-58. ALTERATIONS IN GLIOBLASTOMA TUMOR MICROENVIRONMENT TRANSCRIPTOME AFTER TREATMENT WITH PEMBROLIZUMAB
Authors: Majd Nazanin , Yang Liu , Williford Garret , Alfaro-Munoz Kristin , Dasgupta Pushan , Heimberger Amy , Kannan Kasthuri , Huse Jason , Bhat Krishna , de Groot John
Published: November 2023

BACKGROUND

Immune checkpoint inhibitors (CPI) have failed to show survival benefit in glioblastoma. Understanding the alterations in the tumor microenvironment after treatment with CPI is crucial for development of immunotherapy in glioblastoma. We previously reported our window-of-opportunity trial of pembrolizumab in GBM (NCT02337686). In the current study, we obtained 8 paired glioblastoma tumors pre- and post-treatment with pembrolizumab and conducted RNA sequencing analysis to understand the alterations in the tumor microenvironment transcriptome in response to pembrolizumab. Method: We conducted bulk RNA-sequencing profiling and differential gene expression analysis to compare the expression levels of patient-derived glioblastoma pre- and post-treatment with pembrolizumab, while controlling for paired information. We performed gene enrichment analysis on the differentially expressed genes. We employed the single sample mww-GST method to assess the enrichment of various immune cell types that were previously identified, across the two groups.

RESULTS

Our analysis revealed 294 down-regulated and 259 up-regulated genes in the post treatment samples. The gene enrichment analysis demonstrated that the up-regulated genes were enriched in pathways related to the immune system. The single sample mwwGST analysis indicated a consistent overall up-regulation of expression in immune cell infiltration. Notably, T cell-related signatures, such as CD4, CD8, and NKT exhibited significantly higher infiltration in the post-treatment group. Interestingly, gene ontology analyses showed upregulation of phagocytosis and antigen presentation gene modules in the post-treatment samples. Additionally, we found neuronal components and genes related to hyperexcitability and synaptic connectivity with an overrepresentation of AMPA and DLG4 pathways in post-treatment tissues.

CONCLUSION

Our data show that in addition to the anticipated infiltration of myeloid and lymphoid cell populations, checkpoint blockade can also unexpectedly influence glioma-neuron interactions, which may represent additional immunotherapy targets in GBM. Further proteomic validation of infiltration of different cell types and their interactome in pre- and post-CPI treated tissue is warranted.
TMIC-67. GLIOBLASTOMA AUGMENTS SYSTEMIC IMMUNUNOSUPPRESSION UPON LOSS OF TESTOSTERONE VIA ALTERATION OF GLUCOCORTICOIDS PRODUCTION
Authors: Lee Juyeun , Lathia Justin , Chung Yoon-Mi , Sharifi Nima , Hao Yue , Berens Michael
Published: November 2023

While sex differences in incidence, genetics, and immune changes are established in glioblastoma (GBM), the specific contribution of sex hormones to these differences has not been fully explored. Testosterone has been shown to have a pro-tumorigenic effect on human and mouse GBM tumor cells. However, the systemic effect of testosterone in an immune competent model has not been tested. To test this, we performed castration or sham surgery on C57BL/6 male mice, followed by intracranial implantation of syngeneic glioma cells. Surprisingly, castrated mice exhibited more aggressive tumor growth compared to sham surgery controls, and this castration-induced aggressiveness could be reversed by administering exogenous testosterone. This finding was further confirmed by chemically blocking androgen receptor signaling using enzalutamide. We observed a significant increase in adrenocorticotropic hormone (ACTH) levels in the serum from castrated mice compared to the sham group after tumor implantation. Additionally, mass spectrometry analysis detected elevated levels of circulating glucocorticoids in castrated mice, and pharmacological blockade of glucocorticoid receptor using mifepristone reversed the shorted survival in castrated mice, but not in sham control. Flow analysis revealed decreased production of anti-tumor cytokines such as IFN-γ and TNF-α in CD4+ and CD8+ T cells from tumors and lymph nodes in castrated mice, suggesting systemic immunosuppression in these animals. Indeed, castration of immune-compromised mice, specifically NSG and RAG1KO strains, did not result in reduced survival. Moreover, when GBM cells were subcutaneously implanted into the flank, tumor growth in castrated mice was decelerated compared to sham controls. We also observed significantly lower ACTH levels in the flank tumor model compared to the brain tumor model, indicating a brain-specific effect of steroid hormones on tumor control. Taken together, these findings demonstrate that testosterone regulates T cell function through glucocorticoids, ultimately affecting GBM growth in a site-specific manner.
TMIC-83. THE MOLECULAR AND SPATIAL ARCHITECTURE OF AN IMMUNE-RICH GLIOMA SUBTYPE
Authors: Kumar Anupam , Wang Lin , Solomon David , Hervey-Jumper Shawn , Berger Mitchel , Diaz Aaron , Phillips Joanna
Published: November 2023

Diffuse glioma exhibit an immunosuppressive microenvironment, yet glioma subsets driven by RAF-alterations exhibit an increased immune signature. In pleomorphic xanthoastrocytoma (PXA), we identified CXCL14 as an important factor promoting a cytotoxic T cell response. The molecular and spatial relationships within this tumor type, however, are unknown. To address this, we use single nucleus RNA sequencing (snRNAseq), spatial transcriptomics, and spatial molecular imaging to construct a high-resolution molecular landscape of PXA. SnRNAseq was performed on 36,781 cells from 10 tumors, including initial and recurrent pairs, spatial transcriptomes were performed on a total of 91 FOVs comprised of 17 PXAs, and spatial molecular imaging (SMI) of 1,000 RNA probes at subcellular resolution was performed on 48,518 cells from 6 tumors, including two PXA, two pilocytic astrocytoma, and two ganglioglioma. For snRNAseq, neoplastic cells were separated from non-malignant cells based on analysis of inferred copy number alterations. CellChat was used to infer cell-cell communication. For spatial transcriptomics, data from 200-300µm FOVs were normalized and divided into CD3-high versus CD3-low groups. For SMI, cells with fewer than 20 transcripts were eliminated, data were normalized using simple total counts, cells were segmented using the Nanostring pipeline, and semi-supervised clustering was performed. Dual CXCL14 RNAscope and Iba1/CD3 immunostaining confirmed spatial relationships within the tumor. In PXA with high-CD3, differential gene expression analysis demonstrated broad immune-enrichment and identified upregulation of several ligand-receptor pairs. Integrating these data with snRNAseq and cell-cell communication analysis inferred paracrine interactions between tumor cells and T cells. One such factor, CXCL14, was expressed widely by tumor cells but spatial analysis revealed cohesive clusters of CXCL14-high expressing tumor cells. In anaplastic (CNS WHO grade 3) tumors, however, both CXCL14 expression and microglia decreased. These high-resolution molecular analyses of PXA identify dynamic tumor-immune crosstalk regulating the immune microenvironment.
MODL-02. DEVELOPMENT OF RODENT GLIOBLASTOMA MODELS OF MGMT-MEDIATED TEMOZOLOMIDE RESISTANCE
Authors: Lee Teresa , Bhatt Deepti , Sundaram Ranjini , Saltzman W Mark , Bindra Ranjit S , Vasquez Juan C
Published: November 2023

O6-methylguanine-DNA methyltransferase (MGMT) is an enzyme that repairs O6-methylguanine DNA damage lesions generated by alkylators such as temozolomide (TMZ), the standard chemotherapeutic for glioblastoma (GBM) treatment. High MGMT expression leads to TMZ resistance and is correlated with lower survival, making it an important prognostic biomarker and potential therapeutic target. Xenograft models with human GBM cell lines require implantation into immunodeficient animals, precluding the study of MGMT-dependent alkylator sensitivity in the setting of an intact tumor immune microenvironment. In this study, we developed rat and mouse glioma models of MGMT overexpression and characterized response to alkylator therapy. RG2 rat glioma and SB28 mouse glioma cells, which have low endogenous MGMT levels, were transduced with cDNA expressing FLAG-tagged MGMT to generate an isogenic pair. RG2 MGMT+ and SB28 MGMT+ cells showed robust expression of MGMT, which was effectively abrogated by MGMT inhibitors. In vitro cell viability assays showed that MGMT overexpression resulted in increased resistance to TMZ compared to parental cells, and this resistance was reversed when cells were concurrently treated with the MGMT inhibitor lomeguatrib. To model MGMT overexpression in vivo, luciferase-expressing RG2 MGMT+ cells were implanted into the brains of syngeneic Fischer 344 rats. Rats were treated with TMZ at 50mg/kg daily x 5 days via intraperitoneal injection. Tumor growth was measured by bioluminescence imaging and rats were monitored for survival and toxicity. RG2 MGMT+ tumors were highly resistant to TMZ, as treatment did not improve survival or delay tumor growth. Overall, our newly developed isogenic rat and mouse glioma models recapitulate MGMT-dependent TMZ sensitivity and provide useful preclinical tools for studying MGMT as a biomarker and potential therapeutic target in GBM. In addition, these syngeneic models facilitate studies on the immune modulation of chemotherapeutic agents in the context of MGMT expression and allows for testing of chemoimmunotherapy combinations.