Predictive modeling of dose fall-off in radiosurgery could assist in clinical decision-making when prescribing a treatment plan with minimized toxicity risk. The purpose of this study is to develop a predictive dose fall-off model. Materials/Methods: We retrospectively reviewed treatment plans from 257 patients (365 lesions) with total doses ranging from 20 to 35Gy in 5 fractions. For each plan, we measured both total volume of the external contour (EXT) and BrainMinusPTV (BMP) receiving P=20% to P=80% of the prescription dose. The model has form y=Fa(PTV)b+/-delta. y=volume of EXT or BMP (cc’s); a and b are curve-fitting coefficients; PTV=total planning target volume (cc’s); F is an adjustment factor (>1) to account for number of targets; delta is the 95% prediction band. F, a, b, and delta were modeled such that dose-fall can be forecast for any PTV and dose level. Results: The model coefficients were as follows: Coefficient EXT BMP a 19927(100×P)exp(-2) 17122(100×P)exp(-2) b 0.42(100×P)exp(0.17) 0.63 F -0.0156×(100×P)+2.5517 delta 384467×(100×P)exp(-2.3159) The table can be used to determine the model for any P from 20% to 80%. Example: the EXT receiving 50%, P=0.5, a=8.0, b=0.82, F=1.8, delta=45. Thus, EXT-50=8(PTV0.82) or 1.8×8(PTV0.82) for 1-3 or >3 targets, respectively,+/-45cc’s. The model was verified against published values of dose fall-off from linacs. Conclusion: A predictive dose fall-off model was generated for linac-based radiosurgery. The model can be used for quality assurance or for inter-institutional comparisons. Ongoing work is being conducted to extend the model to a SRS cones system.

We examined functional outcomes and quality of life of whole brain radiotherapy (WBRT) with integrated fractionated stereotactic radiotherapy boost (FSRT) for brain metastases treatment. Methods Eighty seven people with 1-3 brain metastases were enrolled on this Phase II trial of WBRT (30Gy/10)+simultaneous FSRT, (60Gy/10). Results Mean (Min-Max) baseline KPS, Mini Mental Status Exam (MMSE) and FACT-BR quality of life were 83 (70-100), 28 (21-30) and 143 (98-153). Lower baseline MMSE (but not KPS or FACT-Br) was associated with worse survival after adjusting for age, number of metastases, primary and extra-cranial disease status. Crude rates of deterioration (>10 points decrease from baseline for KPS and FACT-Br, MMSE fall to<27) ranged from 26-38% for KPS, 32-59% for FACT-Br and 0-16%for MMSE depending on the time-point assessed with higher rates generally noted at earlier time points (<6months post-treatment). Using a linear mixed models analysis, significant declines from baseline were noted for KPS and FACT-Br (largest effects at 6 weeks to 3 months) with no significant change in MMSE. Conclusions The effects on function and quality of life of this integrated treatment of WBRT+simultaneous FSRT were similar to other published series combining WBRT+SRS.

The purpose of this study was to investigate the impact of an intervention designed to support newly diagnosed primary brain tumour patients. The intervention involved a structured, one time meeting between newly diagnosed patients and trained volunteer “veteran” primary brain tumour patients. Methods Two trained volunteers met for a single, face to face meeting on an individual basis with a total of 10 newly diagnosed patients. A combination of questionnaires and interviews were used to investigate the impact of the intervention for the new patients and the volunteers. Results: The intervention appeared to be of substantial value for both groups of participants. Analysis revealed that the newly diagnosed patients experienced a range of benefits, including those related to the themes of: increased hope; valued guidance; hearing what it’s really like; overcoming aloneness; and realignment of priorities. Veteran patients experienced a sense accomplishment and decreased anxiety as a result of the intervention. Only minor adverse effects and challenges were reported. Conclusions The findings provide initial evidence that the experimental intervention has the potential to be a safe, effective means of promoting psycho-social well-being in newly diagnosed patients and may also have positive effects for veteran patients. Further investigation into the use of one to one, peer support for brain tumour patients is an important research priority.

Improving neurocognitive outcomes following treatment for brain metastases have become increasingly important. We propose that a brief telephone-based neurocognitive assessment may improve follow-up cognitive assessments in this palliative population. Aim: To prospectively assess the feasibility and reliability of a telephone based brief neurocognitive assessment compared to the same tests delivered face-to-face. Methods: Brain metastases patients to be treated with whole brain radiotherapy (WBRT) were assessed using a brief validated neurocognitive battery at baseline, at 1 month and 3 months following WBRT (in person and over the phone). The primary outcome was feasibility and inter-procedural (in person versus telephone) reliability. The secondary objective was to evaluate the change in neurocognitive function before and after WBRT. Results: Out of 39 patients enrolled, 82% of patients completed the baseline in-person and telephone neurocognitive assessments. However, at 1 month, only 41% of enrolled patients completed the in-person and telephone cognitive assessments and at 3 months, only 10% of patients completed them. Results pertaining to reliability and change in neurocognitive function will be updated. Conclusion: The pre-defined definition of feasibility (at least 80% completion for face to face and telephone neurocognitive assessments) was met at baseline. However, a large proportion of participants did not complete either telephone or in person neurocognitive follow-up at 1 month and at 3 months post-WBRT. Attrition remained a challenge for neurocognitive testing in this population even when a telephone-based brief assessment was used.

Due to the non-curative nature of high grade brain tumours “difficult discussions” about goals of care, advance care planning, palliative care, and end of life are inherent to the practice of the neuro-oncology team. Clinician and patient barriers are common and may include anxiety about destroying hope, lack of readiness to discuss end of life topics, difficulty managing emotional responses, and concerns over competency in facilitating difficult discussions. Nonetheless, clinician comfort and skill in facilitating these discussions is critical and can impact patient perception of illness, coping response, and ability to make decisions about care. Methods At our regional cancer centre, a novel quality improvement initiative was designed to bring monthly case presentation of “difficult discussions” into a pre-existing weekly multi-disciplinary case conference (MCC). We will describe the rationale and developmental processes behind this initiative. Roughly 15 neuro-oncology clinicians attended each case conference, with guest attendance from palliative care and psychosocial oncology. Clinician groups represented included physicians (77%), nurses (8%), nurse practitioners (10 %), and occupational therapists (5%). Baseline and monthly surveys were administered to determine clinicians’ self- rated practices, skills, and attitudes towards “difficult discussions”. Results Early findings indicate that the initiative has been well-received. Physicians indicated highest levels of agreement with the statement “I feel that having difficult discussions is part of my responsibility”. Non physician groups indicated the greatest agreement that the intervention is beneficial to their practice. Discussion: Our challenges and successes may help guide others to incorporate a similar initiative at disease-site meetings.

Individuals with primary brain tumors experience a range of physical, cognitive and psychosocial sequelae which impact their independence, safety and quality of life. These impairments may be addressed through rehabilitation intervention. Despite acknowledgement that timely rehabilitation services over the course of the disease process is of benefit, few outpatient neuro-oncology treatment teams include a rehabilitation professional. Purpose: The aims are: (1) to describe a rehabilitation consultation model of care integrated into outpatient neuro-oncology treatment for individuals with primary brain tumors; and (2) to describe the characteristics of individuals referred for rehabilitation services. Methods: This retrospective descriptive study examined data from 200 individuals that received rehabilitation consultation from January 2015 to March 2016 at Princess Margaret Hospital, Pencer Brain Tumor Centre. Information on patient demographics, referral characteristics, and number of patient care visits was collected. Descriptive statistics were calculated. Preliminary Results: Of all patients, (n=195), the most common diagnosis is glioblastoma, 39% (n=76), and 50% are 50-69 years of age (M=55, SD=15.0). The most common reason for initial referral was decline in physical functioning, strength and balance (41%). In 77% of cases, patients were seen immediately at the time of referral. In total, 540 consultations were completed (face-to-face=230, telephone=310) with 2.78 on average (SD=4.0) per patient. Conclusion: Given the range of symptoms that individuals with primary brain tumors experience coupled with changes in functional status as the disease progresses, integrated and timely rehabilitation consultation is feasible.

Human embryonic stem cells (hESCs) are known for their indefinite self-renewal ability and pluripotent nature. However, during long-term culture, normal hESCs can undergo neoplastic transformation and acquire enhanced self-renewal ability and aberrant differentiation potential. These transformed-hESCs (trans-hESCs) exhibit high expression of the pluripotent gene, LIN28A. LIN28A, an RNA binding protein, is known: for its role in self-renewal of hESCs, as a reprogramming factor for generating induced-pluripotent stem cells and as a potent oncogene in several poorly differentiated, highly malignant human cancers. Despite its multiple functions, how LIN28A contributes to neoplastic transformation of normal hESCs is poorly understood. Our preliminary data demonstrate that following LIN28A knockdown, trans-hESCs display normal hESCs morphology consisting of both pluripotent colony cells surrounded by more differentiated fibroblast-like cells. Neural precursors derived from LIN28A knockdown trans-hESCs also revert back to a state of normal cell morphology and growth. Further analyses revealed that the expression levels of stage-specific embryonic antigen (SSEA3), OCT3/4 and NANOG decreases and are comparable to that observed in normal hESCs following LIN28A downregulation. Expression of miRNA targets of LIN28A such as let7i and mir125b was increased to levels seen in normal hESCs. These preliminary results indicate that LIN28A is a major contributing factor to neoplastic transformation of hESCs and that this process can be reversed by cellular “reprogramming”. This study will enhance our understanding of role of LIN28A in the transformation process in various human cancers thus, underscoring the value of hESCs and their neoplastic-derivatives as cellular and molecular model for studying tumor progression.

Medulloblastoma (MB), the most common malignant pediatric brain tumor, is categorized into four molecular subgroups. Given the high rate of metastatic dissemination at diagnosis and recurrence in Group 3 MBs, these patients have the worst clinical outcome with a 5-year survivorship of approximately 50%. By adapting the existing COG (Children’s Oncology Group) Protocol for children with newly diagnosed high-risk MB, for treatment of immuno-deficient mice intracranially engrafted with human MB brain tumour initiating cells we aim to identify and characterize the treatment-refractory cell population in Group 3 MBs. Mice were sacrificed at multiple time points during the course of tumor development and therapy: (i) at engraftment; (ii) post-radiation; (iii) post-radiation and chemotherapy; and (iv) at MB recurrence. MB cell populations recovered separately from brains and spines were comprehensively profiled for gene expression analysis, stem cell and molecular features to generate a global, comparative profile of MB cells through therapy. We report a higher expression of CD133, Sox2 and Bmi1 in addition to increased self-renewal capacity following chemoradiotherapy treatment. The enrichment map constructed from global gene expression analysis showed an increase in pathways regulating self-renewal, DNA repair and chemoresistance post-therapy despite the apparent decrease in tumour size and vascularity. Additionally, from gene expression at MB recurrence, we identified a list of genes that negatively correlate with survival in patients diagnosed with Group 3 MB. A differential genomic profile of the “treatment-responsive” tumors against those that fail therapy may contribute to discovery of novel therapeutic approaches for the most aggressive subgroup of MB.

Medulloblastoma (MB) is the most common malignant pediatric brain tumour, and is categorized into four molecular subgroups, with Group 3 MB having the worst prognosis due to the highest rate of metastatic dissemination and relapse. In this work, we describe the epigenetic regulator Bmi1 as a novel therapeutic target for treatment of recurrent Group 3 MB. Through comparative profiling of primary and recurrent MB, we show that Bmi1 defines a treatment-refractory cell population that is uniquely targetable by a novel class of small molecule inhibitors. We have optimized an in vivo mouse-adapted therapy model that has the advantage of generating recurrent, human, treatment-refractory MBs. Our preliminary studies showed that although chemoradiotherapy administered to mice engrafted with human MB showed reduction in tumour size, Bmi1 expression was enriched in the post-treatment residual tumour. Furthermore, we found that knockdown of Bmi1 in human recurrent MB cells decreases proliferation and self-renewing capacities of MB cells in vitro as well as both tumour size and extent of spinal leptomeningeal metastases in vivo. Oral administration of a potent Bmi1 inhibitor, PTC 028, resulted in a marked reduction in tumour burden and an increased survival in treatment cohort. Bmi1 inhibitors showed high specificity for MB cells and spared normal human neural stem cells, when treated with doses relevant for MB cells. As Group 3 medulloblastoma is often metastatic and uniformly fatal at recurrence, with no current or planned trials of targeted therapy, an efficacious agent such as Bmi1 inhibitor could be rapidly transitioned to clinical trials.

Brain tumors are the most common solid tumors in children in Canada. While technological advances have increased their survival rates, survivors of childhood brain tumors (SCBT) often develop obesity, which can reduce lifespan and quality of life. While adiposity is a known factor for cardiometabolic disorders in the general population, adiposity patterns in SCBT have not been determined. This study aims to investigate how adiposity patterns differ between SCBT and non-cancer controls, and how lifestyle and treatment factors may contribute to these patterns. Methods: Fifty-nine SCBT and 108 non-cancer controls were recruited from the clinics at McMaster Children’s Hospital. Sociodemographic and lifestyle details were collected using standardized tools to assess diet, physical activity, and sleep. Brain tumor type, location and treatment details were obtained from medical records. Total and visceral adiposity were determined by total fat mass (FM) as well as waist-to-hip (WHR) and waist-to-height ratio (WHTR). Results: SCBT have higher total and visceral adiposity, while BMI is similar to controls. Female SCBT who received radiotherapy and/or chemotherapy have higher adiposity. A dietary pattern of white bread and fried foods with low dark bread was positively associated with adiposity. Lower physical activity levels, but not sleep durations, were associated with higher adiposity. Conclusion: SCBT have higher visceral and total adiposity than non-cancer controls. Sex, chemoradiotherapy, high fat diet, and physical inactivity, can contribute to these adiposity patterns. These results provide multiple points of entry to design interventions that reduce adiposity, and may improve long-term outcomes in SCBT.

To describe the epidemiology of children under age 3 diagnosed with central nervous system tumors in Canada. Case ascertainment: Retrospective observation study of children under age 3 diagnosed with neoplasm involving the central nervous system between 1990 and 2005 at 13 of the Canadian pediatric oncology centres. Results: Case ascertainment was 573 persons. Below 6 months of age at diagnosis, no gender difference was seen and the commonest location of tumor was supratentorial. Embryonal tumors were the commonest, increased head circumference and vomiting were the commonest presenting symptom and survival rates were poor. Over 6 months of age at diagnosis, male predominance occurred and commonest location of tumor was the cerebellum. The commonest tumor was astrocytic, vomiting was the commonest presenting symptom and survival was better than in the under 6-month age group. Conclusion: Over the study period, the incidence rate and degree of resection remained stable. A trend to increased survival in children with ependymal tumors occurred; while, with medulloblastoma, survival decreased.

Proton beam therapy (PBT) offers compelling advantages in physical dose distribution compared to photon therapy. There are increasing numbers of gantry-based proton facilities worldwide but no such facilities exist in Canada. To access PBT, Canadian patients must travel abroad for treatment at high cost. In the face of limited access, this report seeks to provide recommendations for the selection of patients most likely to benefit from PBT and suggests an out-of-country referral process. METHODS: A systematic literature search for studies between January 1990 and May 2014 evaluating clinical outcomes after PBT. A draft report was developed through review of evidence, externally reviewed, and approved by the Alberta Health Services Cancer Care Proton Therapy Guidelines steering committee. RESULTS: Proton therapy is often used to treat tumours close to radiosensitive tissues, and children at risk of developing significant late effects of radiation therapy (RT). Local control rates with PBT appear similar to or, in some cases, higher than photon RT in uncontrolled and retrospective studies. Randomized trials comparing equivalent doses of PBT and photon RT are not available. SUMMARY: Referral for PBT is recommended for patients being treated with curative intent, with an expectation for long-term survival, and who are able and willing to travel abroad to a proton facility. Commonly accepted indications for referral include chordoma and chondrosarcoma, intraocular melanoma, and solid tumours in children and adolescents occurring in patients with greatest risk of long-term sequelae. Current data do not provide sufficient evidence to recommend routine referral of patients with most head and neck, breast, lung, gastrointestinal tract, and pelvic cancers including prostate cancer. It is recommended that all referrals be considered by a multidisciplinary team to select appropriate cases.

Proton therapy enables normal tissue sparing for curative-intent treatment of children with cancer who require radiation therapy. In the USA and elsewhere, proton therapy is being rapidly adopted, and many new proton centres are being established. Without a proton centre in Canada, children and their families must travel abroad for treatment at high cost and has raised the question whether a Canadian proton therapy facility is needed. METHODS: Canadian Pediatric Oncology centres were surveyed to assess current and future clinical practices. Needs were modeled by screening the Alberta Cancer Registry, ascertaining the number of children eligible for proton RT and comparing to the number who actually received this therapy. RESULTS: Most centres (63%) referred children, and 49 children were referred abroad between 2008 and 2013. Referrals were estimated to increase to 36 cases per annum across Canada. Most respondents (75%) supported that proton therapy will reduce late effects in most or selected cases compared to photon therapy. The registry search revealed 37,170 patients irradiated of which 379 children (1.0%) were potentially eligible for proton therapy, accounting for 15.9% of the new cases of childhood cancers diagnosed in Alberta over the interval. CONCLUSIONS: A strong perceived need for a pediatric proton therapy in Canada was identified. Proton therapy utilization was lower than modeled needs. Future referrals are anticipated to increase, with annual estimated cost of approximately $60 million spent outside of Canada that could be invested within the Canadian health care economy. These issues are worthy of further national discussion.

Gangliogliomas (GG) are low grade neuroepithelial tumours of the central nervous system (CNS) comprised of neoplastic glial and neuronal cells. There are no animal models or cell lines to study. Microarray data of a panel of low grade gliomas including GG revealed overexpression of the DLX2 homeobox gene required for tangential interneuronal migration and differentiation in the embryonic forebrain. We hypothesized that DLX2 regulates neural versus glial cell fate decisions in CNS progenitors and that GG are arrested in development. METHODS: DLX2 expression was examined along with glial fibrillary acidic protein (GFAP; glial marker) and synaptophysin and/or NeuN (neuronal markers) expression in a cohort of GG tumours using immunohistochemistry and dual immunofluorescence labelling of formalin fixed paraffin embedded (FFPE) tissue sections. BRAF mutational status was also assessed. RESULTS: In our discovery cohort (Genoa), 10/30 samples (33%) expressed DLX2. In our validation cohort (Edmonton), 22/36 (61%) expressed nuclear DLX2 and 12/22 DLX2+cases had BRAF mutations (55%; 11 V600E, 1 V600G). 12/18 cases with BRAF mutations were DLX2+(67%). One heavily pre-treated child with progressive cervicomedullary GG has had a very good partial response to BRAF inhibitor therapy. All 22 DLX2+tumours co-expressed GFAP (100%) and 21/22 (95%) also expressed synaptophysin or NeuN. CONCLUSIONS: Our results support GG as neurodevelopmental tumours arising from bipotential CNS progenitors that are arrested at the neural-glial cell fate "decision" point. Biological or differentiation-based treatments could be considered+/- BRAF inhibitors for those GG with/without the V600E mutation, respectively.

Dianhydrogalactitol (VAL-083) is a unique bi-functional alkylating agent causing N7-guanine-methylation and inter-strand DNA crosslinks. VAL-083 readily crosses the blood-brain barrier, accumulates in brain tumor tissue and has shown activity in prior NCI-sponsored clinical trials against various cancers, including glioblastoma (GBM) and medulloblastoma. VAL-083 is also active against GBM cancer stem cells and acts as a radiosensitizer independent of O6-methylguanine-DNA methyltransferase activity (in contrast to e.g. temozolomide and BCNU). Here we report new insights into VAL-083 mechanism of action by showing that VAL-083 induces irreversible cell-cycle arrest and cell death caused by replication-dependent DNA damage. In lung (H2122, H1792, H23, A549) and prostate (PC3, LNCaP) cancer cell lines VAL-083 treatment caused irreversible S/G2 cell-cycle arrest and cell death (IC50 range 3.06-25.7 µM). VAL-083 pulse-treatment led to persistent phosphorylation of DNA double-strand breaks (DSB) sensors ATM, single-strand DNA-binding Replication Protein A (RPA32), and histone variant H2A.X, suggesting persistent DNA lesions. After 10 months in culture with increasing VAL-083 concentrations, H1792 and LNCaP cells survive at concentrations up to 9.4 µM and 7.4 µM, respectively, suggesting that efficient resistance mechanisms are not easily acquired by the cancer cells. Taken together with previous results showing that VAL-083 circumvents cisplatin-resistance and is less dependent on p53 activity than cisplatin, these results suggest a molecular mechanism for VAL-083 that differs from both TMZ, BCNU and cisplatin. They further suggest that irreparable DNA damage induced by VAL-083 is impervious to common strategies employed by cancer cells to escape effects of alkylating drugs used in GBM treatment.

Somatic mutations in the Capicua (CIC) gene were first identified in Type I low-grade gliomas (LGGs), which are characterized by 1p/19q co-deletions and IDH mutations. They are found at frequencies of ~50-70% in this glioma subtype, and have since been identified in ~40% of stomach adenocarcinomas (STADs) of the microsatellite instability (MSI) subtype; however, the role of these somatic mutations in malignancy has yet to be established. In Drosophila, CIC functions as a transcriptional repressor whose activity is inhibited upon activation of the mitogen-activated protein kinase (MAPK) signalling pathway. Though mammalian CIC appears to retain these functions, only three of its target genes have been established in human cells: ETV1, ETV4, and ETV5 (ETV1/4/5). To further probe CIC’s transcriptional network, we developed CIC knockout cell lines and performed transcriptomic and proteiomic analyses in these and in control cell lines expressing wild type CIC, identifying a total of 582 differentially expressed genes. We also used RNA-seq data from The Cancer Genome Atlas (TCGA) for Type I LGGs and STADs to perform additional differential expression analyses between CIC-deficient and CIC-expressing samples. Though gene-level overlap was limited between the three contexts, we found that CIC appears to regulate the expression of genes involved in cell-cell adhesion, metabolism, and developmental processes in all three contexts. These results shed light on the pathological role of CIC mutations and may help explain why these have been associated with poorer outcome within Type I LGGs.

Glioblastoma (GBM) is an aggressive brain tumor that is resistant to conventional radiation and cytotoxic chemotherapies. We hypothesize that brain tumor initiating cells (BTICs), a subpopulation of treatment-resistant cells with stem cell properties cause tumor relapse and a subset of neural stem cell genes regulate BTIC self-renewal, driving GBM recurrence. We adapted the existing treatment protocol for adults with primary GBM for in vivo treatment of immunocompromised mice engrafted with GBMs. Post-chemoradiotherapy, the recovered GFP+GBMs were profiled for self-renewal and expression of critical stem cell genes. Using invitro and invivo gain-of-function/loss-of-function experiments, we investigated the regulatory functions of Bmi1 in primary neural stem & progenitor cells (NSPCs) and GBM tumor formation. Finally, global RNA-Seq profiling was performed to understand the consequences of Bmi1 dysregulation on target gene expression. GBM cells showed an increase in Bmi1 levels post-chemoradiotherapy, suggesting the presence of a treatment-refractory BTICs. GFP+cells extracted from treated xenografts had higher self-renewal and BTIC marker expression. Although treated mice responded to therapy, we observed tumor relapse with increased Bmi1 expression. Knockdown of Bmi1 diminished self-renewal and proliferation of GBM cells and delayed tumorigenesis, highlighting a critical role for Bmi1 in tumor maintenance. Conversely, over-expressing Bmi1 in NSPCs failed to initiate tumor formation in vivo. Using high-throughput sequencing data, we generated a map of signaling pathways dysregulated in GBM that may lead to tumor recurrence. Our data confirms the existence of a rare treatment-refractory BTIC population with enhanced self-renewal capacity that escapes therapy and drives tumor relapse.

Glioblastoma (GBM), an aggressive primary adult brain tumor, is feared for its near uniformly fatal prognosis. Despite the use of aggressive treatment including surgical resection, radiotherapy and chemotherapy, the outcome of patients with GBM has failed to improve significantly. Numerous studies have implicated CD133+GBM subpopulation as driver of chemo- and radio-resistance. CD133 expression correlates with disease progression, recurrence, and poor overall survival of GBM patients. Here, we describe the preclinical evaluation of a recombinant CD133xCD3 bispecific T-cell engager (BiTE) antibody that redirects human polyclonal T cells to CD133+GBM cells, inducing very potent anti-tumor response. CD133-specific BiTE was constructed; with one arm recognizing the tumor antigen (CD133) while the second is specific to CD3 antigen. Using CD133high and CD133low primary GBM lines, we validated the binding of BiTEs to CD133+GBMs and CD3+T cells. In order to test the ability of BiTEs to functionally elicit CD133-specific cytotoxic responses in vitro, we performed killing assays. We observed CD133-specific BiTE mediated T cell activation and redirection to kill CD133-expressing GBM cells in a co-culture of T cells and GBM cells. The killing was more efficient in CD133high GBMs compared to CD133low GBMs, validating its specificity to target CD133+BTICs. Treatment with BiTEs yielded significant reductions in brain tumor burden in vivo. These data offers compelling evidence that BiTE-mediated cytotoxicity against treatment-resistant CD133+GBMs could provide a very potent, specific and can be a novel therapeutic strategy for GBM patients.

Our ongoing work has demonstrated that hexokinase 2 (HK2) but not HK1 or HK3 is a critical mediator of tumour glycolysis and mitochondrial metabolism in Glioblastoma (GB). Furthermore, HK2 is highly expressed in GB but not in normal brain making it an attractive therapeutic target. Our current findings now support that loss of HK2 alters tumor vasculature, increases sensitivity to radiation, and confers a significant survival benefit in several GB xenograft-bearing mice. Using a genome wide transcript analysis, we identified that loss of HK2 attenuates several pro-growth signaling pathways in GB including ERK signaling. Mechanistically, ERK rescue experiments in HK2 depleted cells rescues cell sensitivity to radiation and reduces DNA damage. Furthermore using a systems biology approach and a rationale drug screen we identified several antifungal agents in the azole class as to inhibit tumor metabolism and growth in HK2 expressing GB cells. Loss of HK2 in GB cells dampened the effect of several azoles suggesting that the mechanism of action is mediated in part through HK2. Furthermore, we tested several azole compounds known to cross the blood brain barrier in vivo. Clinically achievable doses of azoles as single agents increased survival in several orthotopic xenograft GB mouse models. In summary, HK2 drives several oncogenic pathways associated with GB including ERK signaling and sensitizes tumour cells to the azole class of antifungals. Future work will determine whether azoles work synergistically with radiation and temozolomide and elucidate the mechanisms by which they inhibit GB growth in HK2 expressing cells.

High-grade gliomas are deadly cancers, and current standard-of-care has demonstrated limited success. The ability to specifically target glioma cells can allow for the development of improved theranostic agents leading to better detection methods, as well as safer anti-cancer therapies. Brevican (Bcan), a CNS-specific protein is upregulated in glioma cells and correlates with tumor progression. Particularly, a Bcan isoform lacking normal glycosylation, called B/bDg is a unique glioma marker and is not expressed in non-cancerous tissues. Therefore, B/bDg represents a valuable target for anti-cancer strategies. We describe here the discovery of novel high-affinity B/bDg-targeted peptides using rapid combinatorial library screening approaches and a microfluidic sorting device of our own design. Briefly, a one-bead-one-compound (OBOC) peptide library was screened against small magnetic particles decorated with B/bDg. Positive “hit” beads labeled with magnetic particles were isolated using an inexpensive but yet, accurate and high-throughput in-house microfluidic magnetic-activated sorter. These hits were exposed to cells expressing B/bDg, and beads with the highest cell association were isolated and sequenced. Seven novel peptides were identified. Cell uptake analyses and blocking studies revealed that 5 of these peptides displayed specific uptake in B/bDg-overexpressing cells. These candidates displayed nano-/micromolar binding affinity for recombinant B/bDg protein. Further analyses of these candidates using confocal microscopy revealed increased peptide binding/uptake in patient-derived glioma stem cells (GSCs) compared with primary human astrocytes. We plan to incorporate these onto multi-functional BBB-penetrating nanoparticles loaded with imaging agents or a drug payload to translate them into highly selective and efficacious brain cancer theranostic agents.