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Purpose:Oncolytic herpes simplex virus-1 (oHSV) infection of brain tumors activates NOTCH, however the consequences of NOTCH on oHSV-induced immunotherapy is largely unknown. Here we evaluated the impact of NOTCH blockade on virus-induced immunotherapy.Experimental Design:RNA sequencing (RNA-seq), TCGA data analysis, flow cytometry, Luminex- and ELISA-based assays, brain tumor animal models, and serum analysis of patients with recurrent glioblastoma (GBM) treated with oHSV was used to evaluate the effect of NOTCH signaling on virus-induced immunotherapy.Results:TCGA data analysis of patients with grade IV glioma and oHSV treatment of experimental brain tumors in mice showed that NOTCH signaling significantly correlated with a higher myeloid cell infiltration. Immunofluorescence staining and RNA-seq uncovered a significant induction of Jag1 (NOTCH ligand) expression in infiltrating myeloid cells upon oHSV infection. Jag1-expressing macrophages further spread NOTCH activation in the tumor microenvironment (TME). NOTCH-activated macrophages increased the secretion of CCL2, which further amplified myeloid-derived suppressor cells. CCL2 and IL10 induction was also observed in serum of patients with recurrent GBM treated with oHSV (rQnestin34.5; NCT03152318). Pharmacologic blockade of NOTCH signaling rescued the oHSV-induced immunosuppressive TME and activated a CD8-dependent antitumor memory response, resulting in a therapeutic benefit.Conclusions:NOTCH-induced immunosuppressive myeloid cell recruitment limited antitumor immunity. Translationally, these findings support the use of NOTCH inhibition in conjunction with oHSV therapy.

Supplementary Figure from NOTCH-Induced MDSC Recruitment after oHSV Virotherapy in CNS Cancer Models Modulates Antitumor Immunotherapy

Supplementary Data from NOTCH-Induced MDSC Recruitment after oHSV Virotherapy in CNS Cancer Models Modulates Antitumor Immunotherapy

Meningioangiomatosis (MA) is a rare process at the intersection of cerebral developmental and neoplastic disorders that often results in epilepsy. We evaluated molecular alterations in MA to characterize its biology and pathogenesis. We searched a comprehensive institutional database for patients with MA treated between 2004 and 2019. Demographic, clinical, surgical, and radiographical data were collected. MA and associated meningioma tissues were evaluated using a next-generation sequencing assay interrogating 1425 cancer-related genes. We studied 5 cases: 3 with MA and 2 with MA associated with a meningioma. Of the MAs associated with a meningioma, 1 had deletions in the NF2 gene in both the MA and the meningioma components, whereas the other had an NF2 deletion in only the MA component. Additional mutations were identified in the MA components, suggesting that MA arises from the meningioma rather than the meningioma resulting from a transformation of the MA. The 3 cases of pure MA showed variants of unknown significance with no alterations in known oncogenic drivers. Our findings provide a starting point to a better understanding of the pathogenesis of this rare lesion. Our study indicates that MA-meningiomas have a neoplastic nature that differs from the hamartomatous/developmental nature of pure MA.

Background Despite multi-model therapy of maximal surgical resection, radiation, chemotherapy, and tumor-treating fields, the median survival of glioblastoma (GBM) patients is less than 15 months. Protein arginine methyltransferase 5 (PRMT5) catalyzes the symmetric dimethylation of arginine residues and is overexpressed in GBM. Inhibition of PRMT5 causes senescence in stem-like GBM tumor cells. LB100, a first-in-class small molecular inhibitor of protein phosphatase 2A (PP2A), can sensitize therapy-resistant tumor cells. Here, we tested the anti-GBM effect of concurrent PRMT5 and PP2A inhibition. Methods Patient-derived primary GBM neurospheres (GBMNS), transfected with PRMT5 target-specific siRNA, were treated with LB100 and subjected to in vitro assays including PP2A activity and western blot. The intracranial mouse xenograft model was used to test the in vivo antitumor efficacy of combination treatment. Results We found that PRMT5 depletion increased PP2A activity in GBMNS. LB100 treatment significantly reduced the viability of PRMT5-depleted GBMNS compared to PRMT5-intact GBMNS. LB100 enhanced G1 cell cycle arrest induced by PRMT5 depletion. Combination therapy also increased the expression of phospho-MLKL. Necrostatin-1 rescued PRMT5-depleted cells from the cytotoxic effects of LB100, indicating that necroptosis caused the enhanced cytotoxicity of combination therapy. In the in vivo mouse tumor xenograft model, LB100 treatment combined with transient depletion of PRMT5 significantly decreased tumor size and prolonged survival, while LB100 treatment alone had no survival benefit. Conclusion Overall, combined PRMT5 and PP2A inhibition had significantly greater antitumor effects than PRMT5 inhibition alone.

Background The prognosis of glioblastoma (GBM) remains dismal because therapeutic approaches have limited effectiveness. A new targeted treatment using MEK inhibitors, including trametinib, has been proposed to improve GBM therapy. Trametinib had a promising preclinical effect against several cancers, but its adaptive treatment resistance precluded its clinical translation in GBM. Previously, we have demonstrated that protein arginine methyltransferase 5 (PRMT5) is upregulated in GBM and its inhibition promotes apoptosis and senescence in differentiated and stem-like tumor cells, respectively. We tested whether inhibition of PRMT5 can enhance the efficacy of trametinib against GBM. Methods Patient-derived primary GBM neurospheres (GBMNS) with transient PRMT5 knockdown were treated with trametinib and cell viability, proliferation, cell cycle progression, ELISA, and western blot were analyzed. In vivo, NSG mice were intracranially implanted with PRMT5-intact and -depleted GBMNS, treated with trametinib by daily oral gavage, and observed for tumor progression and mice survival rate. Results PRMT5 depletion enhanced trametinib-induced cytotoxicity in GBMNS. PRMT5 knockdown significantly decreased trametinib-induced AKT and ERBB3 escape pathways. However, ERBB3 inhibition alone failed to block trametinib-induced AKT activity suggesting that the enhanced antitumor effect imparted by PRMT5 knockdown in trametinib-treated GBMNS resulted from AKT inhibition and not ERBB3 inhibition. In orthotopic murine xenograft models, PRMT5-depletion extended the survival of tumor-bearing mice, and combination with trametinib further increased survival. Conclusion Combined PRMT5/MEK inhibition synergistically inhibited GBM in animal models and is a promising strategy for GBM therapy.

Background Pleomorphic xanthoastrocytomas (PXA) are circumscribed gliomas that typically have a favorable prognosis. Limited studies have revealed factors affecting survival outcomes in PXA. Here, we analyzed the largest PXA dataset in the literature and identify factors associated with outcomes. Methods Using the Surveillance, Epidemiology, and End Results (SEER) 18 Registries database, we identified histologically confirmed PXA patients between 1994 and 2016. Overall survival (OS) was analyzed using Kaplan-Meier survival and multivariable Cox proportional hazard models. Results In total, 470 patients were diagnosed with PXA (males = 53%; median age = 23 years [14-39 years]), the majority were Caucasian (n = 367; 78%). The estimated mean OS was 193 months [95% CI: 179-206]. Multivariate analysis revealed that greater age at diagnosis (≥39 years) (3.78 [2.16-6.59], P < .0001), larger tumor size (≥30 mm) (1.97 [1.05-3.71], P = .034), and postoperative radiotherapy (RT) (2.20 [1.31-3.69], P = .003) were independent predictors of poor OS. Pediatric PXA patients had improved survival outcomes compared to their adult counterparts, in which chemotherapy (CT) was associated with worse OS. Meanwhile, in adults, females and patients with temporal lobe tumors had an improved survival; conversely, tumor size ≥30 mm and postoperative RT were associated with poor OS. Conclusions In PXA, older age and larger tumor size at diagnosis are risk factors for poor OS, while pediatric patients have remarkably improved survival. Postoperative RT and CT appear to be ineffective treatment strategies while achieving GTR confer an improved survival in male patients and remains the cornerstone of treatment. These findings can help optimize PXA treatment while minimizing side effects. However, further studies of PXAs with molecular characterization are needed.

This meeting abstract was removed due to the OA licensing requirements of this journal. The full abstract is listed here : https://www.svin.org/files/SVIN_2021_Abstracts_for_Web.pdf

The inflammatory processes following traumatic brain injury (TBI) have not been fully characterized. We hypothesize that differences in systemic cytokine/chemokine (CC) levels are associated with TBI clinical outcomes. To test this hypothesis, we examined systemic levels of CCs and their relationship with patient outcomes. Plasma from acute TBI subjects was collected at 24–48 h, and the CC levels were measured using a multiplex 41-plex-kit. Clinical outcomes were assessed using the modified Rankin scale (mRS) with good outcomes defined as mRS ≤ 3 and poor outcome as mRS ≥ 4. The differences in CC concentrations between groups were then compared using the Mann-Whitney U test. Seventy-six acute TBI subjects were included in this study. In the mRS ≥ 4 group, interleukin-6 (IL-6) and interleukin-10 (IL-10) were elevated, indicating early activation of immune reaction and modulation. Simultaneously, PDGFAA and RANTES were lower in the mRS ≥ 4 group. Poor outcomes after TBI were associated with elevated levels of IL-6 and IL-10 and lower levels of PDGFAA and RANTES within 24–48 h after injury.

Purpose: Oncolytic herpes simplex virus-1 (oHSV) infection of brain tumors activates NOTCH, however the consequences of NOTCH on oHSV-induced immunotherapy is largely unknown. Here we evaluated the impact of NOTCH blockade on virus-induced immunotherapy. Experimental Design: RNA sequencing (RNA-seq), TCGA data analysis, flow cytometry, Luminex- and ELISA-based assays, brain tumor animal models, and serum analysis of patients with recurrent glioblastoma (GBM) treated with oHSV was used to evaluate the effect of NOTCH signaling on virus-induced immunotherapy. Results: TCGA data analysis of patients with grade IV glioma and oHSV treatment of experimental brain tumors in mice showed that NOTCH signaling significantly correlated with a higher myeloid cell infiltration. Immunofluorescence staining and RNA-seq uncovered a significant induction of Jag1 (NOTCH ligand) expression in infiltrating myeloid cells upon oHSV infection. Jag1-expressing macrophages further spread NOTCH activation in the tumor microenvironment (TME). NOTCH-activated macrophages increased the secretion of CCL2, which further amplified myeloid-derived suppressor cells. CCL2 and IL10 induction was also observed in serum of patients with recurrent GBM treated with oHSV (rQnestin34.5; NCT03152318). Pharmacologic blockade of NOTCH signaling rescued the oHSV-induced immunosuppressive TME and activated a CD8-dependent antitumor memory response, resulting in a therapeutic benefit. Conclusions: NOTCH-induced immunosuppressive myeloid cell recruitment limited antitumor immunity. Translationally, these findings support the use of NOTCH inhibition in conjunction with oHSV therapy.

With limited effective therapeutic strategies, the prognosis for glioblastoma (GBM) is very poor. Our previous study shows that the expression of Protein Arginine Methyltransferase 5 (PRMT5) is upregulated in GBM; its inhibition promotes apoptosis and senescence in differentiated and stem-like tumor cells, respectively. MEK inhibitors, including trametinib, are currently under investigation for GBM therapy. In this study, we tested whether inhibition of PRMT5 can enhance the anti-GBM efficacy of trametinib. Patient-derived primary GBM neurospheres (GBMNS) with transient PRMT5 knockdown were treated with trametinib and cell viability, proliferation, cell cycle progression, ELISA, and western blot analysis were conducted. In vivo, PRMT5-intact and -depleted GBMNS were intracranially implanted in NSG mice and treated with trametinib by daily oral gavage, and tumor progression and mice survival rate were analyzed by MRI and Kaplan-Meier survival curve, respectively. Depletion of PRMT5 increased the cytotoxic effect of trametinib in GBMNS. Trametinib treatment increased the activity of ERBB3 and AKT; With PRMT5 knockdown, the activity of both AKT and ERBB3 decreased significantly. But, inhibition of ERBB3 alone failed to block the trametinib-induced AKT activity suggesting that even though PRMT5 regulates the activity of both ERBB3 and AKT, the enhanced antitumor effect imparted by PRMT5 knockdown in trametinib treated GBMNS is because of AKT inhibition alone. In vivo, PRMT5-depletion extended the survival of the tumor-bearing mice that further increased in combination with trametinib treatment. Interestingly, trametinib treatment alone had no survival benefit.

Background Treatment for glioblastoma (GBM) in elderly (age > 65 years) patients can be affected by multiple geographic and socioeconomic parameters. Correspondingly, the aim of this study was to determine trends in treatment of elderly GBM patients in the United States. Methods All GBM patients in the U.S. National Cancer Database between 2005 and 2016 were retrospectively reviewed. Status of treatment by triple therapy (resection, chemotherapy, and radiation) were summarized and analyzed by U.S. Census region. Results There were 44 338 GBM patients included, with 21 573 (49%) elderly and 22 765 (51%) nonelderly patients with median ages 72 years (range, 65-90 years) and 47 years (range, 40-64 years), respectively. Compared to nonelderly patients, elderly patients had significantly lower odds of being treated by triple therapy (odds ratio, OR = 0.54) as a whole, and its individual elements of resection (OR = 0.78), chemotherapy (OR = 0.46), radiation therapy (OR = 0.52). This was reflected in each U.S. Census region, with the lowest odds of being treated with triple therapy, surgical resection, chemotherapy, and radiation therapy in New England (OR = 0.51) Mountain (OR = 0.66), West North Central (OR = 0.38), and the Middle Atlantic (OR = 0.44), respectively. Multivariable analysis revealed multiple socioeconomic parameters that significantly predicted lower odds of triple therapy in the elderly. Conclusions In the United States alone, there exists geographic disparity in the treatment outcomes of elderly GBM patients. Multiple socioeconomic parameters can influence access to treatment modalities for elderly patients compared to younger patients in different geographic regions, and public health initiatives targeting these aspects may prove beneficial conceptually to optimize and homogenize clinical outcomes.

Although foreign medical graduates (FMGs) have been essential to the US physician workforce, the increasing competitiveness has made it progressively challenging for FMGs to match in US neurosurgery programs. We describe geographic origins and characteristics associated with successful match into US neurosurgery training programs.Retrospective review of AANS membership data (2007-2017). Scopus was used to collect bibliometrics.From 2009 neurosurgical residents, 165 (8.2%) were FMGs. Most were male (n = 148; 89.6%) with a median age of 34.0 years. Top six feeder countries (TFC) included India (13.9%; n = 23), Lebanon and Pakistan (9.1%; n = 15), Caribbean Region (7.2%; n = 12), Mexico (6.67%; n = 11), and Greece (3.6%; n = 6). Compared to FMGs from non-top feeder countries (NTFC), TFC FMGs had higher H-indices (2 vs 4, p = 0.049), greater number of publications (2 vs 5, p = 0.04), were more likely to have an MBBS/MBBCh (n = 38 vs n = 17, p = 0.03), and had twice as many candidates from major feeder medical schools that successfully matched into a US neurosurgery program (n = 43 vs NTFC = 20, p 0.001). NTFC FMGs were almost 3-times more likely to match at an affiliated neurosurgery program (8 vs TFC = 3, p = 0.03), while TFC FMGs were 1.5-times more likely to match at an NIH Top-40 program (33 vs NTFC = 21, p = 0.03).TFC graduates have higher bibliometrics, frequently come from major feeder schools, and have greater match success at a broader selection of programs and NIH top-40 programs. Future studies characterizing FMG country and medical school origins may enable foreign students to geographically target institutions of interest and could allow US programs to better evaluate foreign training environments.

Diffuse axonal injury (DAI) is a type of traumatic brain injury (TBI) that results from a blunt head injury. In this particular subtype, accelerating-decelerating motions cause white matter tract damage and preferentially impact regions including the corpus callosum and brainstem. The neurological compromise therefore relates to the severity of the axonal insult. The most common mechanism for DAI is high-speed motor vehicle accidents, and the clinical presentation is typically out of proportion to the CT findings. As a result, MRI is the modality of choice. Currently, there are limited therapeutic options, and management is identical to other forms of TBI including intracranial pressure and cerebral perfusion pressure management. As this disease is heterogeneous, survivors have a wide range of functional outcomes.

We examine the impact of age and extent of resection (EOR) on overall survival (OS) in geriatric patients with Glioblastoma (GBM).The SEER 18 Registries was used to identify patients aged 65 and above with GBM from 2000-2016. Patients were categorized into 4 groups based on EOR: Biopsy/Local Excision (B/LE), Subtotal Resection (STR), Gross Total Resection (GTR), and Supratotal Resection (SpTR). Primary endpoint was OS, which was calculated using the Kaplan-Meier method and analyzed by the Log-rank and Wilcoxon-Breslow-Gehan test. Multivariable Cox proportional hazards regression model was utilized to identify factors associated with OS. Likelihood of undergoing SpTR was explored using a multivariable logistic regression model. Results are given as median [IQR] and HR [95 % CI].Among 17,820 geriatric patients with GBM, median age was 73 years [68-78], 44 % were female, 91 % White, and 8% Hispanic. SpTR was performed in 2907 (16 %), GTR was performed in 2451 (14 %) patients, STR in 4879 (28 %), and B/LE in 7396 (42 %). There was a decline in the proportion of patients treated with SpTR with advancing age (65-69 years, 17 % vs 95+ years, 0%; p0.0001), and older age corresponded with a decrease in the odds of undergoing SpTR. In survival analysis, GTR (HR 0.61 [0.58-0.65]) and SpTR (HR 0.65 [0.62-0.68]) were associated with improved survival, even in octogenarian patients.These findings suggest that aggressive surgical resection is associated with improvement in OS in geriatric patients. These results emphasize that age should not influence surgical strategy, as there is a survival benefit from maximal resection in geriatric patients.

Background: Middle meningeal artery (MMA) pseudoaneurysms are rare but can occur secondary to trauma with an associated skull fracture and can present with a variety of hemorrhage patterns. Epidural, subdural, subarachnoid, and intraparenchymal hematomas have all been reported. Given the wide range of clinical presentations and radiographic findings, multiple treatment strategies have been employed, including surgical removal, endovascular intervention, and conservative treatment. MMA pseudoaneurysms typically range from 2 to 5 mm in size and have been shown to have unpredictable growth patterns. Case Description: A 54-year-old male identifying as a Jehovah’s Witness presented after a fall and was found to have an epidural hematoma with an accompanying temporal bone fracture. Imaging demonstrated a traumatic pseudoaneurysm of the MMA. Given the patient’s religious preferences, the emphasis was made during surgical planning for the minimization of blood loss. The epidural hematoma was evacuated, and the MMA pseudoaneurysm was directly visualized and surgically excised after ligation of its tributaries. The patient tolerated the procedure well without significant blood loss and made a complete neurological recovery. Conclusion: A well-circumscribed hypodensity on CT within a surrounding hyperintense collection should raise suspicion of MMA pseudoaneurysm in the setting of overlying temporal bone fracture as supported by previous imaging findings of large MMA pseudoaneurysms. The early detection of MMA pseudoaneurysm is imperative, as the presence may dictate more urgent intervention and changes in operative technique. Although not much is known about the nature and progression of these lesions, surgical excision has remained a safe, reliable method of treatment.

INTRODUCTION Glioblastoma (GBM) is the most common malignant primary brain tumor. With limited effective therapeutic strategies, prognosis for GBM is very poor. Our previous study shows that the expression of Protein Arginine Methyltransferase 5 (PRMT5) is upregulated in GBM; its inhibition promotes anti-GBM effect through apoptosis and senescence of mature and immature tumor cells, respectively. In GBM, RAS-RAF- MEK-ERK signaling is aberrantly activated and promotes tumor growth. Therefore, MEK inhibitors, including trametinib are currently under investigation for GBM therapy. In this study, we tested whether inhibition of PRMT5 can enhance the anti-tumor efficacy of trametinib in GBM. METHODS Patient-derived primary GBM neurospheres (GBMNS) with transient PRMT5 knockdown were treated with trametinib and cell viability, proliferation, cell cycle progression, and western blot analysis were conducted. In vivo, PRMT5-intact and -depleted GBMNS were intracranially implanted in NSG mice and treated with trametinib by daily oral gavage, and tumor progression and mice survival rate were analyzed by MRI and Kaplan-Meier survival curve, respectively. RESULTS Trametinib treatment upregulated the expression of PRMT5 in GBMNS. Depletion of PRMT5 increased the cytotoxic effect of trametinib in GBMNS. In concurrence with the trametinib-induced PRMT5 upregulation, trametinib treatment increased the activity of AKT that was blocked with PRMT5 knockdown. In vivo, PRMT5-depletion extended the survival of the tumor bearing mice that further increased in combination with trametinib treatment. Interestingly, trametinib treatment alone had no survival benefit. CONCLUSION Trametinib treatment induces PRMT5 expression. Depletion of trametinib-induced PRMT5 expression sensitizes GBMNS for trametinib by inhibiting AKT activity.

NOTCH signaling is a method of cell-cell communication where membrane bound NOTCH ligands on signal-sending cells can bind to and initiate cleavage of the NOTCH receptor, releasing NICD which can initiate signal transduction in adjacent “signal-receiving” cells. We have recently shown that oHSV treatment of GBM cells induces NICD cleavage and NOTCH activation in adjacent uninfected glioma cells. RNA sequencing of GBM cells post-infection also uncovered Gene Ontology NOTCH signaling pathway to be significantly upregulated. This activation was induced by viral miRNA-H16, which represses FIH-1 expression. FIH-1 was found to be a negative regulator of Mib1, a ubiquitin ligase, which activates NOTCH ligand-mediated activation of adjacent signal-receiving cells bearing the NOTCH receptor (Otani et al Clin. Can. Res. 2020). Here we have investigated the impact of oHSV-induced NOTCH signaling on the tumor microenvironment. Treatment of brain tumors in immune competent mice with oHSV and NOTCH blocking gamma secretase inhibitor (GSI) induced an anti-tumor memory immune response. Long term survivors in mice treated with the combination also completely rejected subsequent tumor re-challenge in the other hemisphere. UMAP of flow cytometry of tumor-bearing hemispheres and functional analysis of isolated cellular fractions from treated mice showed a significant influx of MDSC cells after oHSV treatment that was rescued in mice treated with oHSV and GSI. Ongoing mechanistic studies are uncovering a significant induction of NOTCH in tumor associated macrophages that aids in recruitment of MDSC cells. Overall these studies have uncovered a significant impact of oHSV therapy on GBM tumor microenvironment and presents opportunities for combination therapies that can help improve therapeutic benefit and anti-tumor immunity.

Oncolytic viruses (OVs) are designed to ablate cancerous cells while sparing non-malignant cells and tissues. In the wake of an active tumor infection, OVs can activate an anti-tumor immune response. Currently, an oncolytic Herpes simplex 1 (HSV-1) derived virus encoding for granulocyte-macrophage colony stimulating factor (GM-CSF) is approved in the US and Europe as a treatment for metastatic melanoma, and an oncolytic adenovirus (oAd) is approved in China for head and neck cancer therapy. Despite the approved use for these indications, this promising biological therapy is currently under-used. However, a multitude of viruses are actively being explored in preclinical animal models and clinically in patients with different malignancies for safety and efficacy. Several ongoing clinical trials evaluate OV utility in combination with other therapies, such as chemotherapeutics and immune checkpoint inhibitors. In this chapter, we highlight some of the barriers faced by OVs and discuss methods used to convert these challenges into opportunities for improvement. Major advancements in this field include engineering OVs to deliver payloads with anti-angiogenic, immune modulatory, or extracellular matrix degrading proteins, as well as in combination with immunotherapies, DNA damaging agents, and stem cells to enhance the therapeutic efficacy of OVs. Despite facing some challenges, there is continued enthusiasm for this innovative and promising biological arsenal in treating cancer.

We describe a patient who developed Corynebacterium striatum native valve endocarditis after receiving two 6-week courses of daptomycin for the treatment of methicillin-resistant Staphylococcus aureus bacteremia and osteomyelitis. The organism exhibited in vitro heteroresistance to daptomycin, with two subpopulations showing daptomycin susceptibility (MIC of ≤0.094 μg/ml) and high-level resistance to daptomycin (MIC of ≥256 μg/ml). The selection of daptomycin-resistant Gram-positive skin flora with the potential of causing invasive disease may be a concern during prolonged courses of daptomycin.

Vancomycin and daptomycin MICs from 161 isolates of methicillin-resistant Staphylococcus aureus (MRSA) were compared using commercial and in-house broth microdilution, Etest, and common automated methods. Vancomycin Etest MICs were higher than those of other methods, whereas the MICs for daptomycin testing were comparable. Vancomycin MICs vary depending on the testing methodology.