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Purpose: Glioblastoma is one of the most lethal cancers in humans, and with existing therapy, survival remains at 14.6 months. Current barriers to successful treatment include their infiltrative behavior, extensive tumor heterogeneity, and the presence of a stem-like population of cells, termed brain tumor–initiating cells (BTIC) that confer resistance to conventional therapies.Experimental Design: To develop therapeutic strategies that target BTICs, we focused on a repurposing approach that explored already-marketed (clinically approved) drugs for therapeutic potential against patient-derived BTICs that encompass the genetic and phenotypic heterogeneity of glioblastoma observed clinically.Results: Using a high-throughput in vitro drug screen, we found that montelukast, clioquinol, and disulfiram (DSF) were cytotoxic against a large panel of patient-derived BTICs. Of these compounds, disulfiram, an off-patent drug previously used to treat alcoholism, in the presence of a copper supplement, showed low nanomolar efficacy in BTICs including those resistant to temozolomide and the highly infiltrative quiescent stem-like population. Low dose DSF-Cu significantly augmented temozolomide activity in vitro, and importantly, prolonged in vivo survival in patient-derived BTIC models established from both newly diagnosed and recurrent tumors. Moreover, we found that in addition to acting as a potent proteasome inhibitor, DSF-Cu functionally impairs DNA repair pathways and enhances the effects of DNA alkylating agents and radiation. These observations suggest that DSF-Cu inhibits proteasome activity and augments the therapeutic effects of DNA-damaging agents (temozolomide and radiation).Conclusions: DSF-Cu should be considered as an adjuvant therapy for the treatment of patients with glioblastoma in both newly diagnosed and recurrent settings. Clin Cancer Res; 22(15); 3860–75. ©2016 AACR.

CQ and BAF restore phospholipid levels and inhibit clonogenicity of IDHmut glioma cells.

CQ and BAF do not affect ER area or phospholipid levels in IDHwt glioma cells.

Oral administration of AZD is compatible with TMZ chemotherapy in vivo.

AZD and TMZ administration do not significantly influence body weights of treated animals.

2-HG induces a reduction in ER area in IDHmut glioma cells.

Purpose: The current standard of care for glioblastoma (GBM) involves a combination of surgery, radiotherapy, and temozolomide chemotherapy, but this regimen fails to achieve long-term tumor control. Resistance to temozolomide is largely mediated by expression of the DNA repair enzyme MGMT; however, emerging evidence suggests that inactivation of MSH6 and other mismatch repair proteins plays an important role in temozolomide resistance. Here, we investigate endogenous MSH6 mutations in GBM, anaplastic oligodendroglial tumor tissue, and corresponding brain tumor–initiating cell lines (BTIC).Experimental Design:MSH6 sequence and MGMT promoter methylation were determined in human tumor samples and BTICs. Sensitivity to temozolomide was evaluated in vitro using BTICs in the absence and presence of O6-benzylguanine to deplete MGMT. The influence of MGMT and MSH6 status on in vivo sensitivity to temozolomide was evaluated using intracranial BTIC xenografts.Results: We identified 11 previously unreported mutations in MSH6 in nine different glioma samples and six paired BTIC lines from adult patients. In addition, MSH6 mutations were documented in three oligodendrogliomas and two treatment-naïve gliomas, both previously unreported findings. These mutations were found to influence the sensitivity of BTICs to temozolomide both in vitro and in vivo, independent of MGMT promoter methylation status.Conclusions: These data demonstrate that endogenous MSH6 mutations may be present before alkylator therapy and occur in at least two histologic subtypes of adult glial neoplasms, with this report serving as the first to note these mutations in oligodendroglioma. These findings broaden our understanding of the clinical response to temozolomide in gliomas. Clin Cancer Res; 20(18); 4894–903. ©2014 AACR.

Molecular and genetic analysis of BTICs identifies subgroups with endogenous mutations in EGFR and PTEN.

Rapamycin partially inhibits growth of most BTICs irrespective of EGFR or PTEN mutational status.

Tumor metabolism is reprogrammed to meet the demands of proliferating cancer cells. In particular, cancer cells upregulate synthesis of the membrane phospholipids phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdE) in order to allow for rapid membrane turnover. Nonetheless, we show here that, in mutant isocitrate dehydrogenase 1 (IDHmut) gliomas, which produce the oncometabolite 2-hydroxyglutarate (2-HG), PtdCho and PtdE biosynthesis is downregulated and results in lower levels of both phospholipids when compared with wild-type IDH1 cells. 2-HG inhibited collagen-4-prolyl hydroxylase activity, leading to accumulation of misfolded procollagen-IV in the endoplasmic reticulum (ER) of both genetically engineered and patient-derived IDHmut glioma models. The resulting ER stress triggered increased expression of FAM134b, which mediated autophagic degradation of the ER (ER-phagy) and a reduction in the ER area. Because the ER is the site of phospholipid synthesis, ER-phagy led to reduced PtdCho and PtdE biosynthesis. Inhibition of ER-phagy via pharmacological or molecular approaches restored phospholipid biosynthesis in IDHmut glioma cells, triggered apoptotic cell death, inhibited tumor growth, and prolonged the survival of orthotopic IDHmut glioma-bearing mice, pointing to a potential therapeutic opportunity. Glioma patient biopsies also exhibited increased ER-phagy and downregulation of PtdCho and PtdE levels in IDHmut samples compared with wild-type, clinically validating our observations. Collectively, this study provides detailed and clinically relevant insights into the functional link between oncometabolite-driven ER-phagy and phospholipid biosynthesis in IDHmut gliomas.Significance: Downregulation of phospholipid biosynthesis via ER-phagy is essential for proliferation and clonogenicity of mutant IDH1 gliomas, a finding with immediate therapeutic implications. Cancer Res; 78(9); 2290–304. ©2018 AACR.

Pharmacological inhibition of EGFR and PI3K/mTORC1/2 signaling in BTICs.

2-HG inhibits PtdCho and PtdE biosynthesis.

Purpose: The EGFR and PI3K/mTORC1/2 pathways are frequently altered in glioblastoma (GBM), but pharmacologic targeting of EGFR and PI3K signaling has failed to demonstrate efficacy in clinical trials. Lack of relevant models has rendered it difficult to assess whether targeting these pathways might be effective in molecularly defined subgroups of GBMs. Here, human brain tumor–initiating cell (BTIC) lines with different combinations of endogenous EGFR wild-type, EGFRvIII, and PTEN mutations were used to investigate response to the EGFR inhibitor gefitinib, mTORC1 inhibitor rapamycin, and dual mTORC1/2 inhibitor AZD8055 alone and in combination with temozolomide (TMZ)Experimental Design:In vitro growth inhibition and cell death induced by gefitinib, rapamycin, AZD8055, and TMZ or combinations in human BTICs were assessed by alamarBlue, neurosphere, and Western blotting assays. The in vivo efficacy of AZD8055 was assessed in subcutaneous and intracranial BTIC xenografts. Kaplan–Meier survival studies were performed with AZD8055 and in combination with TMZ.Results: We confirm that gefitinib and rapamycin have modest effects in most BTIC lines, but AZD8055 was highly effective at inhibiting Akt/mTORC2 activity and dramatically reduced the viability of BTICs regardless of their EGFR and PTEN mutational status. Systemic administration of AZD8055 effectively inhibited tumor growth in subcutaneous BTIC xenografts and mTORC1/2 signaling in orthotopic BTIC xenografts. AZD8055 was synergistic with the alkylating agent TMZ and significantly prolonged animal survival.Conclusion: These data suggest that dual inhibition of mTORC1/2 may be of benefit in GBM, including the subset of TMZ-resistant GBMs. Clin Cancer Res; 20(22); 5756–67. ©2014 AACR.

Figure S1: Preclinical assessment of clioquinol. Figure S2: Preclinical assessment of montelukast. Figure S3: Secondary validation of compounds identified via HTS. Figure S4: Sensitivity of BTICs to TMZ. Figure S5: Copper is required for Disulfiram-mediated cell killing. Figure S6: Cell Viability and Apoptosis in the presence of DSF-Cu. Figure S7: Efficacy to DSF-Cu is independent of MGMT expression. Figure S8: Inhibition of proteasome activity by DSF-Cu. Figure S9: DSF-Cu in combination with TMZ prolongs survival in vivo. Figure S10: DSF-Cu mediated apoptosis in vivo. Table S1: Summary of BTIC Molecular Characterization. Table S2: Summary of Compound Priortization. Table S3: Down regulation of DNA repair genes by DSF-Cu.

Supplementary Figure 1. Detection of MSH6 somatic mutations by cDNA and genomic DNA sequencing. A-D, cDNA sequencing (A) revealed a heterozygous T1219I mutation that was also confirmed by sequencing the genomic DNA of cell line 119 (B) and the fresh frozen tumor from patient 119 (C). The T1219I mutation was not present in genomic DNA from a blood sample of patient 119 (D) demonstrating it to be of somatic rather than germline origin.

Phospholipid biosynthesis is down-regulated in IDHmut glioma cells.

Silencing FAM134b, Atg5 or Atg7 restores phospholipid biosynthesis in IDHmut glioma cells.

2-HG induces ER-phagy in IDHmut glioma cells.

ER-phagy is linked to phospholipid biosynthesis in BT54 neurospheres (A-C), orthotopic IDHmut tumor xenografts (D-J) and IDHmut patient biopsies (K-Q).

Gefitinib inhibits growth of EGFRvIII and PTENwt BTICs.

Supplementary Figure Legends from Dual mTORC1/2 Blockade Inhibits Glioblastoma Brain Tumor Initiating Cells In Vitro and In Vivo and Synergizes with Temozolomide to Increase Orthotopic Xenograft Survival

Effect of 2-HG on cell proliferation of IDH1 wild-type cells for the U87 (A) and NHA (B) models.

Comparison of PDH activity in the various models used in this study.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the basis of the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported. Anaplastic oligodendroglial tumors (AOTs) are chemotherapy-sensitive brain tumors. We report the final very long-term survival results from European Organization for the Research and Treatment of Cancer 26951 and Radiation Therapy Oncology Group 9402 phase III trials initiated in 1990s, which both studied radiotherapy with/without neo/adjuvant procarbazine, lomustine, and vincristine (PCV) for newly diagnosed anaplastic oligodendroglial tumors. The median follow-up duration in both was 18-19 years. For European Organization for the Research and Treatment of Cancer 26951, median, 14-year, and probable 20-year overall survival rates without versus with PCV were 2.6 years, 13.4%, and 10.1% versus 3.5 years, 25.1%, and 16.8% (N = 368 overall; hazard ratio [HR] 0.78; 95% CI, 0.63 to 0.98; P = .033), with 1p19q codeletion 9.3 years, 26.2%, and 13.6% versus 14.2 years, 51.0%, and 37.1% (n = 80; HR 0.60; 95% CI, 0.35 to 1.03; P = .063), respectively. For Radiation Therapy Oncology Group 9402, analogous results were 4.8 years, 16.5%, and 11.2% versus 4.8 years, 29.1%, and 24.6% (N = 289 overall; HR 0.79; 95% CI, 0.61 to 1.03; P = .08), with codeletion 7.3 years, 25.0%, and 14.9% versus 13.2 years, 46.1%, and 37% (n = 125; HR 0.61; 95% CI, 0.40 to 0.94; P = .02), respectively. With that, the studies show similar long-term survival even without tumor recurrence in a significant proportion of patients after first-line treatment with radiotherapy/PCV.

CIC encodes a transcriptional repressor and MAPK signalling effector that is inactivated by loss-of-function mutations in several cancer types, consistent with a role as a tumour suppressor. Here, we used bioinformatic, genomic, and proteomic approaches to investigate CIC’s interaction networks. We observed both previously identified and novel candidate interactions between CIC and SWI/SNF complex members, as well as novel interactions between CIC and cell cycle regulators and RNA processing factors. We found that CIC loss is associated with an increased frequency of mitotic defects in human cell lines and an in vivo mouse model and with dysregulated expression of mitotic regulators. We also observed aberrant splicing in CIC-deficient cell lines, predominantly at 3′ and 5′ untranslated regions of genes, including genes involved in MAPK signalling, DNA repair, and cell cycle regulation. Our study thus characterises the complexity of CIC’s functional network and describes the effect of its loss on cell cycle regulation, mitotic integrity, and transcriptional splicing, thereby expanding our understanding of CIC’s potential roles in cancer. In addition, our work exemplifies how multi-omic, network-based analyses can be used to uncover novel insights into the interconnected functions of pleiotropic genes/proteins across cellular contexts.

Tumor-related epilepsy may respond to chemotherapy. In a previously-published multi-centre randomized clinical trial of 562 elderly glioblastoma patients, temozolomide plus short-course radiotherapy conferred a survival benefit over radiotherapy alone. Seizure outcomes were not reported. We performed an unplanned secondary analysis of this trial’s data. The trial design has been previously reported. Seizures were recorded by clinicians as adverse events and by patients in quality of life questionnaires. A Chi-square test of seizure rates between the two groups (α = 0.05) and a Kaplan–Meier estimator of time-to-first self-reported seizure were planned. Almost all patients were followed until they died. In the radiotherapy alone group, 68 patients (24%) had a documented or self-reported seizure versus 83 patients (30%) in the temozolomide plus radiotherapy group, Chi-square analysis showed no difference (p = 0.15). Patients receiving radiotherapy alone tended to develop seizures earlier than those receiving temozolomide plus radiotherapy (p = 0.054). Patients with seizures had shorter overall survival than those without seizures (hazard ratio 1.24, p = 0.02). This study was not powered to detect differences in seizure outcomes, but temozolomide seemed to have minimal impact on seizure control in elderly patients with glioblastoma. Clinical Trial Registration: NCT00482677 2007-06-05.

Temozolomide (TMZ) is a life prolonging DNA alkylating agent active against glioblastomas (GBM) in which the O6-methylguanine-DNA methyltransferase (MGMT) gene is silenced by promoter methylation. Unfortunately acquired TMZ resistance severely undermines its clinical efficacy. Using an in vitro model, we tested whether poly (ADP-ribose) polymerase-1 and -2 (PARP) inhibition could suppress the emergence of resistance to enhance the effectiveness of TMZ. Using the MGMT-methylated GBM line U251N, in which TMZ resistance can be induced, we developed a method to rapidly recreate mechanisms of TMZ resistance seen in GBMs, including MMR mutations and MGMT re-expression. We then assessed whether TMZ resistant U251N sub-clones could be re-sensitized to TMZ by co-treatment with the PARP inhibitor ABT-888, and also whether the emergence of resistance could be suppressed by PARP inhibition. U251N cultures chronically exposed to TMZ developed discrete colonies that expanded during TMZ treatment. These colonies were isolated, expanded further as sub-clones, and assessed for mechanisms of TMZ resistance. Most resistant sub-clones had detectable mutations in one or more mismatch repair (MMR) genes, frequently MSH6, and displayed infrequent re-expression of MGMT. TMZ resistance was associated with isolated poly(ADP-ribose) (pADPr) up-regulation in one sub-clone and was unexplained in several others. TMZ resistant sub-clones regressed during co-treatment with TMZ and ABT-888, and early co-treatment of U251N parental cultures suppressed the emergence of TMZ resistant colonies. In a model of acquired resistance, co-treatment with TMZ and a PARP inhibitor had two important benefits: re-sensitization of TMZ resistant cells and suppression of TMZ resistance.

Description, Inferring structural variants in cancer single-cell chromatin accessibility data links genetics to chromatin organization., Single-cell epigenomic assays have tremendous potential to illuminate mechanisms of transcriptional control in functionally diverse cancer cell populations. However, application of these techniques to clinical tumor specimens has been hampered by the current inability to distinguish malignant from nonmalignant cells, which potently confounds data analysis and interpretation. Here, we describe Copy-scAT, an R package that uses single-cell epigenomic data to infer copy number variants (CNVs) that define cancer cells. Copy-scAT enables studies of subclonal chromatin dynamics in complex tumors like glioblastoma. By deploying Copy-scAT, we uncovered potent influences of genetics on chromatin accessibility profiles in individual subclones. Consequently, some genetic subclones were predisposed to acquire stem-like or more differentiated molecular phenotypes, reminiscent of developmental paradigms. Copy-scAT is ideal for studies of the relationships between genetics and epigenetics in malignancies with high levels of intratumoral heterogeneity and to investigate how cancer cells interface with their microenvironment.

Background Lymphopenia may lead to worse outcomes for glioblastoma patients. This study is a secondary analysis of the CCTG CE.6 trial evaluating the impact of chemotherapy and radiation on lymphopenia, and effects of lymphopenia on overall survival (OS). Methods CCTG CE.6 randomized elderly glioblastoma patients (≥ 65 years) to short-course radiation alone (RT) or short-course radiation with temozolomide (RT + TMZ). Lymphopenia (mild-moderate: grade 1–2; severe: grade 3–4) was defined per CTCAE v3.0, and measured at baseline, 1 week and 4 weeks post-RT. Preselected key factors for analysis included age, sex, ECOG, resection extent, MGMT methylation, Mini-Mental State Examination, and steroid use. Multinomial logistic regression and multivariable Cox regression models were used to identify lymphopenia-associated factors and association with survival. Results Five hundred and sixty-two patients were analyzed (281 RT vs 281 RT+TMZ). At baseline, both arms had similar rates of mild-moderate (21.4% vs 21.4%) and severe (3.2% vs 2.9%) lymphopenia. However, at 4 weeks post-RT, RT+TMZ was more likely to develop lymphopenia (mild-moderate: 27.9% vs 18.2%; severe: 9.3% vs 1.8%; p

Capicua (Cic) is a transcriptional repressor mutated in the brain cancer oligodendroglioma. Despite its cancer link, little is known of Cic’s function in the brain. We show that nuclear Cic expression is strongest in astrocytes and neurons but weaker in stem cells and oligodendroglial lineage cells. Using a new conditional Cic knockout mouse, we demonstrate that forebrain-specific Cic deletion increases proliferation and self-renewal of neural stem cells. Furthermore, Cic loss biases neural stem cells toward glial lineage selection, expanding the pool of oligodendrocyte precursor cells (OPCs). These proliferation and lineage effects are dependent on de-repression of Ets transcription factors. In patient-derived oligodendroglioma cells, CIC re-expression or ETV5 blockade decreases lineage bias, proliferation, self-renewal, and tumorigenicity. Our results identify Cic as an important regulator of cell fate in neurodevelopment and oligodendroglioma, and suggest that its loss contributes to oligodendroglioma by promoting proliferation and an OPC-like identity via Ets overactivity.

Background We report the analysis involving patients treated on the initial CODEL design. Methods Adults (>18) with newly diagnosed 1p/19q World Health Organization (WHO) grade III oligodendroglioma were randomized to radiotherapy (RT; 5940 centigray ) alone (arm A); RT with concomitant and adjuvant temozolomide (TMZ) (arm B); or TMZ alone (arm C). Primary endpoint was overall survival (OS), arm A versus B. Secondary comparisons were performed for OS and progression-free survival (PFS), comparing pooled RT arms versus TMZ-alone arm. Results Thirty-six patients were randomized equally. At median follow-up of 7.5 years, 83.3% (10/12) TMZ-alone patients progressed, versus 37.5% (9/24) on the RT arms. PFS was significantly shorter in TMZ-alone patients compared with RT patients (hazard ratio [HR] = 3.12; 95% CI: 1.26, 7.69; P = 0.014). Death from disease progression occurred in 3/12 (25%) of TMZ-alone patients and 4/24 (16.7%) on the RT arms. OS did not statistically differ between arms (comparison underpowered). After adjustment for isocitrate dehydrogenase (IDH) status (mutated/wildtype) in a Cox regression model utilizing IDH and RT treatment status as covariables (arm C vs pooled arms A + B), PFS remained shorter for patients not receiving RT (HR = 3.33; 95% CI: 1.31, 8.45; P = 0.011), but not OS ((HR = 2.78; 95% CI: 0.58, 13.22, P = 0.20). Grade 3+ adverse events occurred in 25%, 42%, and 33% of patients (arms A, B, and C). There were no differences between arms in neurocognitive decline comparing baseline to 3 months. Conclusions TMZ-alone patients experienced significantly shorter PFS than patients treated on the RT arms. The ongoing CODEL trial has been redesigned to compare RT + PCV versus RT + TMZ.

Background Oligodendroglioma is a rare primary central nervous system (CNS) tumor with highly variable outcome and for which therapy is usually not curative. At present, little is known regarding the pathways involved with progression of oligodendrogliomas or optimal biomarkers for stratifying risk. Developing new therapies for this rare cancer is especially challenging. To overcome these challenges, the neuro-oncology community must be particularly innovative, seeking multi-institutional and international collaborations, and establishing partnerships with patients and advocacy groups thereby ensuring that each patient enrolled in a study is as informative as possible. Methods The mission of the National Cancer Institute’s NCI-CONNECT program is to address the challenges and unmet needs in rare CNS cancer research and treatment by connecting patients, health care providers, researchers, and advocacy organizations to work in partnership. On November 19, 2018, the program convened a workshop on oligodendroglioma, one of the 12 rare CNS cancers included in its initial portfolio. The purpose of this workshop was to discuss scientific progress and regulatory challenges in oligodendroglioma research and develop a call to action to advance research and treatment for this cancer. Results The recommendations of the workshop include a multifaceted and interrelated approach covering: biology and preclinical models, data sharing and advanced molecular diagnosis and imaging; clinical trial design; and patient outreach and engagement. Conclusions The NCI-CONNECT program is well positioned to address challenges in oligodendroglioma care and research in collaboration with other stakeholders and is developing a list of action items for future initiatives.

Glioblastomas (GBMs) are aggressive brain tumors characterized by extensive inter- and intratumor heterogeneity. Patient-derived models, such as organoids and explants, have recently emerged as useful models to study such heterogeneity, although the extent to which they can recapitulate GBM genomic features remains unclear. Here, we analyze bulk exome and single-cell genome and transcriptome profiles of 12 IDH wild-type GBMs, including two recurrent tumors, and of patient-derived explants (PDEs) and gliomasphere (GS) lines derived from these tumors. We find that PDEs are genetically similar to, and variably retain gene expression characteristics of, their parent tumors. Notably, PDEs appear to exhibit similar levels of transcriptional heterogeneity compared with their parent tumors, whereas GS lines tend to be enriched for cells in a more uniform transcriptional state. The approaches and datasets introduced here will provide a valuable resource to help guide experiments using GBM-derived models, especially in the context of studying cellular heterogeneity.

Low grade astrocytomas (LGAs) are classified based on the mutational status of the isocitrate dehydrogenase (IDH) gene. While IDH wild-type (WT) LGAs evolve rapidly to glioblastoma, mutant tumors generally have a more indolent course. To identify potential drivers of the differential progression of LGAs, we analyzed transcriptomes from The Cancer Genome Atlas. Compared to mutant LGAs, platelet-derived growth factor (PDGF) signaling is enriched in WT cases, andPDGFAis the top overexpressed gene in the pathway. Putative mechanisms for differentialPDGFAexpression included copy number gains of chromosome 7 in WT cases and methylation of thePDGFApromoter in mutant LGAs. Additionally, we found that highPDGFAexpression is associated with aneuploidy, immunosuppressive features, and worse prognosis, and that WT LGAs use multiple means to inactivate the p53 pathway to progress to GBM. Our work highlights the contribution of PDGF gene family towards the unique behaviour of LGAs.STATEMENT OF SIGNIFICANCEThis study of gene expression in LGAs suggests that differential regulation of the PDGF pathway may underlie the different natural histories ofIDHWT andIDHmutant LGAs including divergent evolutionary trajectories to GBM. This insight may inspire new therapeutic strategies to suppress the transformation of LGAs to higher-grade cancers.

Tumor-related epilepsy may respond to chemotherapy. In a previously-published multi-centre randomized clinical trial of 562 elderly glioblastoma patients, temozolomide plus short-course radiotherapy conferred a survival benefit over radiotherapy alone. Seizure outcomes were not reported.We performed an unplanned secondary analysis of this trial's data. The trial design has been previously reported. Seizures were recorded by clinicians as adverse events and by patients in quality of life questionnaires. A Chi-square test of seizure rates between the two groups (α = 0.05) and a Kaplan-Meier estimator of time-to-first self-reported seizure were planned.Almost all patients were followed until they died. In the radiotherapy alone group, 68 patients (24%) had a documented or self-reported seizure versus 83 patients (30%) in the temozolomide plus radiotherapy group, Chi-square analysis showed no difference (p = 0.15). Patients receiving radiotherapy alone tended to develop seizures earlier than those receiving temozolomide plus radiotherapy (p = 0.054). Patients with seizures had shorter overall survival than those without seizures (hazard ratio 1.24, p = 0.02).This study was not powered to detect differences in seizure outcomes, but temozolomide seemed to have minimal impact on seizure control in elderly patients with glioblastoma.NCT00482677 2007-06-05.

Tumor metabolism is reprogrammed to meet the demands of proliferating cancer cells. In particular, cancer cells upregulate synthesis of the membrane phospholipids phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdE) in order to allow for rapid membrane turnover. Nonetheless, we show here that, in mutant isocitrate dehydrogenase 1 (IDHmut) gliomas, which produce the oncometabolite 2-hydroxyglutarate (2-HG), PtdCho and PtdE biosynthesis is downregulated and results in lower levels of both phospholipids when compared with wild-type IDH1 cells. 2-HG inhibited collagen-4-prolyl hydroxylase activity, leading to accumulation of misfolded procollagen-IV in the endoplasmic reticulum (ER) of both genetically engineered and patient-derived IDHmut glioma models. The resulting ER stress triggered increased expression of FAM134b, which mediated autophagic degradation of the ER (ER-phagy) and a reduction in the ER area. Because the ER is the site of phospholipid synthesis, ER-phagy led to reduced PtdCho and PtdE biosynthesis. Inhibition of ER-phagy via pharmacological or molecular approaches restored phospholipid biosynthesis in IDHmut glioma cells, triggered apoptotic cell death, inhibited tumor growth, and prolonged the survival of orthotopic IDHmut glioma-bearing mice, pointing to a potential therapeutic opportunity. Glioma patient biopsies also exhibited increased ER-phagy and downregulation of PtdCho and PtdE levels in IDHmut samples compared with wild-type, clinically validating our observations. Collectively, this study provides detailed and clinically relevant insights into the functional link between oncometabolite-driven ER-phagy and phospholipid biosynthesis in IDHmut gliomas. Significance: Downregulation of phospholipid biosynthesis via ER-phagy is essential for proliferation and clonogenicity of mutant IDH1 gliomas, a finding with immediate therapeutic implications. Cancer Res; 78(9); 2290–304. ©2018 AACR.

BACKGROUND PCV+RT substantially prolongs survival in AO patients, but long-term CF and QOL implications are unclear. We compared CF and QOL by treatment arm in RTOG 9402 participants and evaluated the impact that baseline characteristics had on CF, QOL, and survival. METHODS CF and QOL were evaluated using the Mini Mental State Exam (MMSE) and Brain-Quality of Life (B-QOL) scale at baseline and annually. Scores were analyzed between treatment arms at each time point for patients with ≥ 10 years of follow-up data. Shared parameter models evaluated MMSE and B-QOL scores and survival for all patients. RESULTS 42/148 (28.4%) participants in PCV+RT and 20/143 (14%) in RT alone arms survived ≥ 10 years. 35/42 and 39/42 (PCV+RT) and 18/20 and 17/20 (RT) participants completed baseline B-QOL and MMSE assessments, respectively. B-QOL scores did not differ between treatment groups at any time-point. Among 16 patients (10 PCV+RT, 6 RT) who completed year 10 MMSE evaluations, mean MMSE score at 10 years was higher in the RT arm (29.83 [95% CI 22.1, 30.0] vs. 26.50 [95% CI 29.4, 30.0], P= 0.04). Change in MMSE and B-QOL scores from baseline did not differ significantly between treatment groups at any time. In shared parameter models including all patients with baseline assessments, MMSE and B-QOL scores decreased over time (MMSE P= 0.0189, B-QOL P= 0.0005), but this did not differ by treatment group (MMSE P= 0.5727, B-QOL P= 0.3592). Younger age and higher KPS predicted better scores (MMSE P < 0.0001, P = 0.0002; B-QOL P = 0.0043, P = 0.0007). PCV+RT predicted better survival in both models. CONCLUSIONS PCV+RT improves survival in AO. Shared parameter models show decrease in MMSE and B-QOL over time. However, relative to RT alone, the addition of PCV did not impact change in CF and QOL over time.

BACKGROUND Imagining ways to prevent or treat glioblastoma (GBM) have been hindered by a lack of understanding of its pathogenesis. Although platelet derived growth factor-A (PDGFA) overexpression may be an early event, critical details of the biology of GBM, and tools to study its initiation have been lacking. Indeed, many PDGF-driven models replicate its microscopic appearance, but not genomic architecture. Recently, we reported an in vitro model of GBM initiation that overcomes this barrier to authenticity. METHODS We used a method developed to establish neural stem cell cultures to investigate the effects of PDGF-A on cells derived from the subventricular zone (SVZ), a putative region where the cells of origins for GBM are derived. We micro-dissect SVZ tissue from p53-null and wild-type adult mice, culture cells in media supplemented with PDGF-A, and assess cell viability, proliferation, mitotic capacity, and genome stability. RESULTS Paradoxical to its canonical role as a growth factor, we observe abrupt and substantial cell death in PDGF-A. Abnormal mitosis was the first observable alteration and occurred immediately in cells of both p53 wild-type and null genotypes: wild-type cells did not survive in PDGF-A, whereas a fraction of null cells evade apoptosis. Evading cells displayed attenuated proliferation accompanied by early chromosomal gains and losses. After approximately 100 days in PDGF-A, surviving cells suddenly proliferate rapidly, acquire growth factor independence, and become tumorigenic in immune-competent mice. Transformed cells continue to display highly abnormal mitotic phenotypes with complex karyotypes similar to GBM, had a neural progenitor cell (NPC) lineage profile, and were resistant to PDGFR-alpha inhibition. CONCLUSION Abnormal mitosis induced by PDGF-A initiates and perpetuates the genome instability that transforms p53-null neural progenitor cells to yield cancers with the types of recurring chromosomal gains and losses that characterize human GBM.

BACKGROUND Glioblastoma is associated with a poor prognosis in the elderly. Survival has been shown to increase among patients 70 years of age or younger when temozolomide chemotherapy is added to standard radiotherapy (60 Gy over a period of 6 weeks). In elderly patients, more convenient shorter courses of radiotherapy are commonly used, but the benefit of adding temozolomide to a shorter course of radiotherapy is unknown.METHODS We conducted a trial involving patients 65 years of age or older with newly diagnosed glioblastoma. Patients were randomly assigned to receive either radiotherapy alone (40 Gy in 15 fractions) or radiotherapy with concomitant and adjuvant temozolomide.RESULTS A total of 562 patients underwent randomization, 281 to each group. The median age was 73 years (range, 65 to 90). The median overall survival was longer with radiotherapy plus temozolomide than with radiotherapy alone (9.3 months vs. 7.6 months; hazard ratio for death, 0.67; 95% confidence interval [CI], 0.56 to 0.80; PCONCLUSIONS In elderly patients with glioblastoma, the addition of temozolomide to short-course radiotherapy resulted in longer survival than short-course radiotherapy alone. Funded by the Canadian Cancer Society Research Institute and others; ClinicalTrials. gov number, NCT00482677.)

IDH-wildtype GBM is the most common variant of this cancer and occurs in older adults. Unfortunately patients’ tumors are either inherently resistant to standard treatment, which includes radio- and chemo-therapy, or acquire resistance during the therapeutic process. Additionally, although effective in other cancers, targeted therapies have yielded disappointing results in GBM, perhaps because the fully developed disease has significant cellular and molecular heterogeneity, allowing the tumour to adapt to treatments. Better insight into managing GBM might result from a detailed knowledge of its initiating events, which have not yet been elucidated. With this in mind, we developed a mouse model of GBM in which the earliest stages can be studied. This ex vivo model recreates GBM by culturing subventricular zone (SVZ) cells, the putative ‘cell of origin’ of GBM in platelet-derived growth factor A (PDGFA). Under this condition SVZ cells from p53 null mice transform, becoming exogenous growth factor independent and tumorigenic in immune-competent mice. In contrast, wildtype SVZ cells do not proliferate in PDGFA and null cells in EGF/FGF do not transform. To discover why p53 null SVZ cells uniquely transform in PDGFA, we performed array comparative genomic hybridization (aCGH) on cells before and after transformation in PDGFA and whole genome sequencing (WGS) on transformed cells and tumours generated from PDGFA-transformed cells. aCGH and WGS revealed that the genomic landscape of transformed cells displayed a striking similarity to that observed in primary human GBM. Specifically, these studies showed that chromosomal alterations are a hallmark of culturing SVZ cells in PDGFA, an intriguing finding considering GBM is also characterized by a specific landscape of copy number alterations. This model may resemble the pathogenesis of human GBM and be leveraged to investigate the early stages of tumorigenesis, further leading to the development of preventative strategies and novel therapeutics.

Glioblastoma multiforme (GBM) is the most deadly brain tumor, and currently lacks effective treatment options. Brain tumor-initiating cells (BTICs) and orthotopic xenografts are widely used in investigating GBM biology and new therapies for this aggressive disease. However, the genomic characteristics and molecular resemblance of these models to GBM tumors remain undetermined. We used massively parallel sequencing technology to decode the genomes and transcriptomes of BTICs and xenografts and their matched tumors in order to delineate the potential impacts of the distinct growth environments. Using data generated from whole-genome sequencing of 201 samples and RNA sequencing of 118 samples, we show that BTICs and xenografts resemble their parental tumor at the genomic level but differ at the mRNA expression and epigenomic levels, likely due to the different growth environment for each sample type. These findings suggest that a comprehensive genomic understanding of in vitro and in vivo GBM model systems is crucial for interpreting data from drug screens, and can help control for biases introduced by cell-culture conditions and the microenvironment in mouse models. We also found that lack of MGMT expression in pretreated GBM is linked to hypermutation, which in turn contributes to increased genomic heterogeneity and requires new strategies for GBM treatment.