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BACKGROUND Older age is a poor prognostic factor for glioblastoma (GBM) patients. We tested whether the intrinsic molecular landscape of the tumor may contribute to this poor prognosis. METHODS In accordance with the 2021 WHO classification scheme, we included only isocitrate dehydrogenase (IDH) wild type GBM. Based on published literature, we defined older as age > 65. RNA expression, gene amplification, tumor mutational burden (TMB) and mutational profiles were analyzed in three unique datasets: Tempus (n = 1,410), Caris (n = 1,432), and TCGA (n = 557). Comparison were made between < 65 and ³ 65 year olds using Pearson’s Chi-squared tests, Fisher’s exact tests, or Wilcoxon rank-sum where appropriate. RESULTS From our evaluable gene sets, TERT promoter mutations were more prevalent in patients ³ 65 years old (Caris 82.64 vs 77.27%, p = 0.016; Tempus 58.0 vs 49.0%, p = 0.002). There were no significant differences in PDCD1, CD274, CD3E, TNFRSF18, CD40, CD8A, TNFRSF4, CTLA4, HAVCR2, TNFSF9, CD274, or CDKN2A; PDL-1 (by IHC); dMMR/MSI-H, TMB; CDK6 amplification, EGFR amplification, EGFR, EGFRvIII, EGFR fusions, MET fusions, PTEN, TP53, or NF-1. MGMT promoter methylation (Caris data) was more common in the older group (49.73 v 34.14%, p < 0.001). TGCA data demonstrated that gene expression, TMB, and methylation did not change significantly with age. Additionally, PCOLCE2 and SLC10A4 were differentially methylated, and missense mutations, of any type, were more common in the older group (p=0.006). CONCLUSION Despite worse survival outcomes for older patients with IDHwt GBM as compared to younger counterparts, the molecular landscape is similar at the genomic, transcriptomic and epigenomic levels. The key exception is TERT promoter mutations that are more common in older GBM patients. Poorer survival is therefore not likely to be attributable solely to intratumoral factors.

The proportion of aging populations affected by dementia is increasing. There is an urgent need to identify biological aging markers in mid-life before symptoms of age-related dementia present for early intervention to delay the cognitive decline and the onset of dementia. In this cohort study involving 1,676 healthy participants (mean age 40) with up to 15 years of follow up, we evaluated the associations between cognitive function and two classes of novel biological aging markers: blood-based epigenetic aging and neuroimaging-based brain aging. Both accelerated epigenetic aging and brain aging were prospectively associated with worse cognitive outcomes. Specifically, every year faster epigenetic or brain aging was on average associated with 0.19-0.28 higher (worse) Stroop score, 0.04-0.05 lower (worse) RAVLT score, and 0.23-0.45 lower (worse) DSST (all false-discovery-rate-adjusted p

Immune-related therapies have revolutionized the management of cancer. Oncolytic viruses are now considered part of the immunotherapy armamentarium and have shown promise in clinical trials of patients with glioblastoma. These studies have suggested that tumor microenvironment remodeling is required to achieve an effective response in solid tumors. Here, we showed that Delta-24-RGDOX (DNX-2440), an oncolytic adenovirus expressing the T cell activator OX40L, triggered antitumor immune responses. However, Delta-24-RGDOX also elicited paradoxical activation of the cytokine-driven immunosuppressive IDO-kynurenine-AhR circuitry. The IDO-kynurenine-AhR cascade had the dual effects of preventing optimum viral replication and decreasing the virus-initiated antitumor immune response. To enhance virotherapy, we combined Delta-24-RGDOX with clinically relevant IDO inhibitors. This combination therapy increased the frequency of activated CD8+ T cells and decreased the frequencies of immunosuppressive MDSC and Treg populations in animal models of gliomas and melanoma. Functional studies demonstrated that the IDO blockade-dependent activation of immune cells against tumor antigens could be reversed by the oncometabolite kynurenine. The concurrent targeting of effectors and suppressors in the tumor immune landscape significantly prolonged the survival of glioma- and melanoma-bearing mice. Our data identified the striking role of immunosuppressive pathways in the resistance of solid tumors to oncolytic virotherapy. Specifically, the activity of the tumor microenvironment IDO circuitry was responsible, at least partially, for the remodeling of local immunosuppression after tumor infection. Combining molecular and immune-related therapies may improve outcomes in human gliomas and other cancers treated with virotherapy.

The symbiotic interactions between cancer stem cells and the tumor microenvironment (TME) are critical for tumor progression. However, the molecular mechanism underlying this symbiosis in glioblastoma (GBM) remains enigmatic. Here, we show that circadian locomotor output cycles kaput (CLOCK) and its heterodimeric partner brain and muscle ARNT-like 1 (BMAL1) in glioma stem cells (GSCs) drive immunosuppression in GBM. Integrated analyses of the data from transcriptome profiling, single-cell RNA sequencing, and TCGA datasets, coupled with functional studies, identified legumain (LGMN) as a direct transcriptional target of the CLOCK–BMAL1 complex in GSCs. Moreover, CLOCK-directed olfactomedin-like 3 (OLFML3) upregulates LGMN in GSCs via the hypoxia-inducible factor 1-alpha (HIF1A) signaling. Consequently, LGMN promotes microglial infiltration into the GBM TME via upregulating CD162, and polarizes infiltrating microglia towards an immune-suppressive phenotype. In GBM mouse models, inhibition of the CLOCK–OLFML3–HIF1A–LGMN–CD162 axis reduces intratumoral immune-suppressive microglia, increases CD8+ T cell infiltration, activation and cytotoxicity, and synergizes with anti-PD1 therapy. In human GBM, the CLOCK-regulated LGMN signaling correlates positively with microglial level and poor prognosis. Together, these findings uncover the CLOCK–OLFML3–HIF1A–LGMN axis as a molecular switch that controls microglial biology and immunosuppression, thus revealing potential new therapeutic targets for GBM patients.

OBJECTIVE The median age of onset for glioblastoma (GBM; IDHwt) is 68-70 years. Age is a strong prognostic factor for GBM patient outcomes such that overall survival in older adults is less than their younger counterparts – even after adjustment for MGMT promoter methylation status. Aging is associated with increased levels of senescence in the brain. Several age-related neurological disorders have been shown to improve with senolytic treatments. Here, we explored the effects and therapeutic neutralization of syngeneic brain tumors on increasing senescence levels in the extratumoral brain (ie. outside of the brain tumor) of young and old mice. METHODS General RNA-sequencing, as well as single-cell (sc) RNA-sequencing was performed on extratumoral tissue from young (8-12 weeks) and older adult (80-90 weeks) C57BL/6 mice with or without GL261 and key markers were validated with RT-PCR. The combined effects of the senolytics, dasatinib and quercetin, with radiation, anti-PD-1 mAb, and IDO enzyme inhibitor treatment, was also investigated. RESULTS General- and sc-RNA sequencing revealed a distinct gene expression profile in the extratumoral brain of older mice with syngeneic GL261 as compared to all other groups. RT-PCR results confirmed that the brain tumor increased gene expression for senescence levels, p53, and NFkB signaling in the older adult extratumoral brain. Expression of the senescence marker p16INK4A was primarily localized to oligodendrocyte progenitor cells in the older adult brain. The combinatorial treatment of senolytics with RT, anti-PD-1 mAb, and IDO enzyme inhibitor led to a synergistic survival benefit in older adult mice with GL261 as compared to the treatment with senolytics, or immunotherapy, alone. CONCLUSIONS The data suggest that the extratumoral brain may be responsible in-part for the poorer outcomes of older adults with GBM and that treatment approaches that target senescent cells may provide clinical benefit.

INTRODUCTION Indoleamine 2,3-dioxygenase 1 (IDO) is an immunosuppressive enzyme that catabolizes the essential amino acid, tryptophan (Trp), into the metabolite, kynurenine. IDO is expressed in >90% of patient resected GBM. IDO suppresses the anti-brain tumor immune response, in-part, through non-metabolic activities. To determine how IDO non-metabolically suppresses the anti-GBM immune response, IDO-protein degrader (IDO-proteolysis targeting chimera; IDO-PROTAC) effects were studied in multiple human models of GBM. METHODS The IDO-expressing GBM cell lines, U87, U138, as well as the patient derived xenograft (PDX) line, GBM43, were treated with either IDO-PROTAC, mutant PROTAC, IDO enzyme inhibitor, or IDO siRNA, followed by RNA-seq analysis and/or mass spectrometry with quantitative proteomics using tandem mass tag (TMT) labelling. RESULTS Transcriptomic analysis revealed differentially expressed genes that were commonly regulated after treatment with the IDO-PROTAC as compared to treatment with the mutant PROTAC or IDO enzyme inhibitor groups in U87, U138, and GBM43 cells. Mass spectrometry analysis found 34 unique proteins that were differentially expressed inside of human GBM cells, with an additional 20 unique proteins that were identified in the supernatant of cultured human GBM cells after IDO-PROTAC treatment. Meta-analysis of the transcriptomic and proteomic analyses identified a novel factor that was unique to IDO-PROTAC treatment. GO terms that were enriched after IDO-PROTAC treatment identified nucleoside kinase activity as well as metallocarboxypeptidase activity. CONCLUSIONS This study discovered multiple new targets and pathways that immunosuppressive IDO regulates through a non-metabolic function. Functional analyses that validate the newly-discovered IDO-dependent, IDO-enzyme independent factors, are ongoing.

OBJECTIVE Previous work indicates poorer survival outcomes for older glioblastoma (GBM) patients ≥ 65 years of age as compared to younger patients < 65 years of age. The cellular mechanisms associated with this age-dependent survival difference remain elusive. Here we evaluated the overall survival of young and old immunocompetent mice with intracranial brain tumors that were depleted for specific immune cell populations. METHODS Young 6-8 weeks of age vs old 80+ weeks of age C57BL/6 mice were treated for up to 3 weeks with either IgG isotype control antibodies or with depleting antibodies against murine CD4, CD8, or NK1.1, beginning at 3 days prior to- and every 3 days post-intracranial injection of the mouse brain tumor cell lines, GL261 or CT-2A. Overall survival was compared between groups. Additionally, absolute peripheral blood mononuclear cell (PBMC) counts for CD3+ T cells, CD4+ T cells, and CD8+ T cells were analyzed between aneurysm control- and GBM-patients. RESULTS Older adult mice, but not younger mice, with either intracranial GL261 or CT-2A cell-based brain tumors have a significantly decreased overall survival when depleted for CD4+ T cells as compared to the IgG control-treated group, as well as groups depleted for CD8+ T- or NK-cells (P < 0.05). Coincidently, older GBM patients have fewer CD4+ T cells as compared to younger GBM patient counterparts (P < 0.05). CONCLUSIONS The data suggest that the levels of CD4+ T cells play more important roles in the survival of old subjects with GBM than in the younger subjects. A mechanistic understanding for this CD4+ T cell-dependent survival benefit is ongoing.

Oncolytic viruses are considered part of immunotherapy and have shown promise in preclinical experiments and clinical trials in a small fraction of patients. To improve the response rate, it is necessary to reshape the tumor microenvironment that shields the tumor from the immune system of the patient. We engineered Delta-24-RGDOX (DNX-2440), an oncolytic adenovirus to express the T-cell activator OX40L, which triggered, in murine glioblastoma models, a dramatic reshaping of the tumor microenvironment dominated by changes in immune processes in an RNA-seq analysis of ingenuity pathways. Paradoxically, network analyses also revealed that Delta-24-RGDOX induced robust activation of the cytokine-driven immunosuppressive IDO-Kynurenine-AhR circuitry, indicating a potential mechanism of resistance of gliomas to oncolytic virotherapy. To reverse this immunosuppression, we combined Delta-24-RGDOX with clinically relevant IDO inhibitors to treat glioma-bearing mice. The combined therapy decreased the activation of the IDO network without affecting viral activity. Flow cytometry assays revealed a decrease in the presence of the immunosuppressive cell populations, MDSCs and Tregs, which presence was higher in Delta-24-RGDOX-treated tumors. These data were further confirmed in gene set enrichment analyses. Functional co-culture studies showed that the combined therapy activated splenocytes against tumor antigens and that this activation was reversed by Kynurenine. Importantly, the combination treatment eradicated the tumors in a CD4-dependent manner and significantly prolonged the survival of glioma-bearing mice. Altogether, these studies indicate that the combination treatment promotes an adaptive immune response while decreasing the immunosuppression caused by the virus-induced IDO activation. Furthermore, our data identified the striking role of immunosuppressive pathways in the resistance of gliomas to oncolytic virotherapy. Specifically, the activity of the tumor microenvironment IDO circuitry was responsible, at least partially, for the remodeling of local immunosuppression after tumor infection. Combining molecular and immune-related therapies may improve outcomes in human gliomas treated with virotherapy.

Glioblastoma is the most common primary malignant brain tumor in adults. Age is a prognostic factor for grade IV glioma (GIV) survival, where older adults 65 and older, tend to have quicker mortality compared to adults 18-64. This may be due to intrinsic aspects of the aged host, including age-dependent changes to the brain and immune systems. We studied pharmacologic management of GIV patients treated with medications affecting the brain, immune, and other systems for associations with age and survival. Electronic records for 1,208 GIV patients were collected at a single institution from 1/1/2000 to 9/8/2021 and used to construct a multivariable time-dependent cox model that examined intra-cohort hazards associated with 14 different categories of outpatient medications. Date of diagnosis was identified as the start-time and subject death was used to define the event-time. Patients who were alive or lost to follow-up were censored to last recorded date. Survival time was calculated as the difference between diagnosis date and event time or censorship. For positive control, we confirmed that younger and older patients experienced an improved hazard with temozolomide. Strikingly, younger, but not older patients, experienced increased hazard with a steroid prescription (1.46 [1.12,1.90], **). In contrast, older, but not younger patients experienced improvements in hazard with prescription of neurological medications including benzodiazepines (0.47 [0.27, 0.80] **) and anti-convulsants (0.28 [0.08, 0.90] *), in addition to heart failure treatments including angiotensin II inhibitors (0.48 [0.27, 0.85] *) and diuretics (0.30 [0.15, 0.87] *). Patients prescribed antidepressants didn’t show improved hazard across younger and older GIV patients, which consistent with our previously published work. These data indicate novel associative benefits due to prescription of select pharmacologic agents that vary with patient age. This work may be used to better understand therapeutic approaches that selectively benefit younger vs. older adults with GIV.

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.