Search

INTRODUCTION: The blood brain barrier is a critical limiting step to achieving therapeutic CNS drug concentrations. We have developed a poly(lactic-co-glycolic acid)/poly(ethylene glycol) (PLGA/PEG)-based Platform Technology to interstitially deliver multiple chemotherapy agents from a single thermo-setting paste, potentially filling the 3-week therapy gap that currently exists between surgery and commencement of radiotherapy in the treatment of high grade gliomas. Here we evaluate mouldable PLGA/PEG paste for combined temozolomide (TMZ) and etoposide (ETOP) delivery in an orthotopic high grade glioma model. METHODS: Drug release and preserved stability of the active TMZ molecule (AIC) was evaluated by fluoroscopic and LC-mass spectrometer based methods. In vitro cytotoxicity of released TMZ/ETOP was evaluated against high grade glioma cell lines and patient-derived primary cultures using metabolic assays. In vivo efficacy and overall survival were evaluated in the syngenic orthotopic 9L glioma rat model of intra cavity chemotherapy. RESULTS: TMZ and ETOP were released from PLGA/PEG alone or in combination over 2 weeks in vitro. Cytotoxicity of released drugs in vitro is comparable to directly applied agents, demonstrating the retained molecular integrity of TMZ/ETOP upon loading and releasing from PLGA/PEG. Both high (20% w/w TMZ / 50% w/w ETOP) and low (10% w/w TMZ / 25% w/w ETOP) doses were well tolerated in vivo, with no observable weight loss nor neurological deficits. Significant survival benefits from PLGA/PEG/TMZ/ETOP therapy were observed compared to surgery alone (49 vs. 14 days; p < 0.001), surgery with blank paste (49 vs. 14 days; p < 0.001) or surgery with daily oral TMZ (49 vs. 33 days; p < 0.004). CONCLUSIONS: This study demonstrates that interstitial delivery of TMZ/ETOP achieves significant glioma survival benefits. As such, PLGA/PEG paste applied to the post-surgical resection cavity offers a realistic opportunity for localised control of residual disease in pediatric and adult high grade gliomas.

Atypical teratoid/rhabdoid tumors (AT/RT) are highly aggressive, malignant tumors and are the most common malignant brain tumor in children under 6 months of age. Currently, there is no standard treatment for AT/RT. Recent studies have reported potential anti-tumoral properties of ribavirin, a guanosine analog and anti-viral molecule approved by the Food and Drug Administration for treatment of hepatitis C. We previously demonstrated that ribavirin inhibited glioma cell growth in vitro and in vivo. Based on these results and the fact that no pre-clinical model of ribavirin in AT/RT exists, we decided to investigate the effect of ribavirin on several human AT/RT cell lines (BT12, BT16, and BT37) both in vitro and in vivo. We provide evidence that ribavirin has a significant impact on AT/RT cell growth and increases cell cycle arrest and cell death, potentially through modulation of the eIF4E and/or EZH2 pathways. Interestingly, using scratch wound and transwell Boyden chamber assays, we observed that ribavirin also impairs AT/RT cell migration, invasion, and adhesion. Finally, we demonstrate that ribavirin significantly improves the survival of mice orthotopically implanted with BT12 cells. Our work establishes that ribavirin is effective against AT/RT by decreasing tumoral cell growth and dissemination and could represent a new therapeutic option for children with this deadly disease.

Tumor progression, limited efficacy of current standard treatments, and the rise in patient mortality are associated with gene expression caused by the synergistic action of intratumoral hypoxia and HIF-1α activation. For this reason, recent investigations have focused on HIF-targeting therapeutic agents, with encouraging preclinical and clinical results in solid tumors. Here we describe the efficacy of a HIF-1α inhibitor, Acriflavine, and demonstrate its potency against brain cancer. This safe antibacterial dye induces cell death and apoptosis in several glioma cell lines, targets HIF-1α–mediated pathways, and decreases the level of PGK1, VEGF and HIF-1α in vitro and in vivo. Administered locally via biodegradable polymers, Acriflavine provides significant benefits in survival resulting in nearly 100% long term survival, confirmed by MRI and histological analyses. This study reports preclinical evidence that this safe, small molecule can contribute to brain tumor therapy and highlights the significance of HIF-1α-targeting molecules.

A Target Animal Safety protocol was used to examine adverse events in male and female Fischer F344/NTac rats treated with increasing doses of a subcutaneous implant of a lipid suspension of buprenorphine. A single injection of 0.65 mg/kg afforded clinically significant blood levels of drug for 3 days. Chemistry, hematology, coagulation, and urinalysis values with 2- to 10-fold excess doses of the drug-lipid suspension were within normal limits. Histopathology findings were unremarkable. The skin and underlying tissue surrounding the drug injection were unremarkable. Approximately 25% of a cohort of rats given the excess doses of 1.3, 3.9, and 6.5 mg/kg displayed nausea-related behavior consisting of intermittent and limited excess grooming and self-gnawing. These results confirm the safety of cholesterol-triglyceride carrier systems for subcutaneous drug delivery of buprenorphine in laboratory animals and further demonstrate the utility of lipid-based carriers as scaffolds for subcutaneous, long-acting drug therapy.

The use of appropriate analgesia in laboratory mice may be suboptimal because of concerns about adverse events (AE). Target Animal Safety trials were conducted to determine the safety of an extended-release suspension of buprenorphine. Drug or control suspensions were injected subcutaneously in surgically-treated BALB/c mice anesthetized with ketamine–xylazine to mimic post-operative conditions in which the compound might commonly be administered. Single and repeat five-fold (5×) excesses of the 3.25 mg/kg intended dose were used to provoke potential AE. Trials included prospective measurements of weight changes, blood chemistry, hematology, and histopathology. Clinical and histopathology findings were similar in drug-treated and control mice in a four-day trial using a single 16.25 mg/kg, 5× overdose of the drug. In a 12-day trial, which used a total buprenorphine dose of 48.75 mg/kg, clinical and histopathology values were also similar in control and drug-treated female mice. In the male arm of the repeat-overdose trial, two of eight mice died on the morning of day 12, three days following the third 16.25 mg/kg overdose administration. Histopathology did not reveal a cause of death. In a 14-month trial using a single 3.25 mg/kg dose of the drug, no significant findings identified potential AE. These findings indicate a high tolerance to an extended-release buprenorphine suspension administered post-operatively in mice with appropriate husbandry.

Dramatic improvements in cancer survival rates have been achieved over the past 40 years, with a one-year median survival for all cancers in 1971 climbing to a predicted 6-year median survival today.1 Colon cancer has proven to have the greatest improvement, from a median survival of 7 months in 1971 to a current estimate of 10 years. Encouraging improvements in survival for primary brain malignancies have also been noted, but not to such a profound extent. Despite significant advances in neuroimaging, surgical technique, radiation therapy, and conventional chemotherapy, median survival for WHO grade IV astrocytoma (glioblastoma multiforme [GBM]) remains 30 ATPs produced through oxidative phosphorylation.7 Theories have been proposed regarding the evolutionary advantage to malignant cells of the additional role of glycolytic enzymes as regulators of transcription and apoptosis.8 The breakdown of glucose also provides many of the cellular building blocks required for production of the proteins, nucleic acids, and lipids required for replication.7 In addition, aerobic glycolysis facilitates extracellular acidosis, selecting for cancer cells with more resistant phenotypes that can withstand anaerobic conditions once the oxygen supply has been outgrown.9 Some glycolytic enzymes have also been noted to play a role in regulating apoptosis. With the upregulation of glycolysis, therefore, malignant cells would be less likely to undergo cell death. Hexokinase (HK) is the first regulatory enzyme within glycolysis that catalyzes the conversion of glucose to glucose-6-phosphate, capturing glucose molecules within the cell. HK has 4 isoforms: I, II, III, and IV. HK II is found to be upregulated in many tumor cell lines10 and primarily promotes anabolic functions such as glycogen and lipid synthesis.11 Wolf et al recently found HK II to be a key mediator of aerobic glycolysis in GBMs, as opposed to predominant HK I expression in normal brain tissue and low-grade gliomas.12 3-Brompyruvate (3-BrPA) is a potent ATP inhibitor and direct inhibitor of HK II.13,14 3-BrPA has been shown to be well tolerated in vivo at doses required to significantly inhibit tumor ATP production, decrease lactic acid production, and promote apoptosis, with little noted toxicity to normal tissue at therapeutic doses.15–17 While shown to be effective in glioma cell lines,16 a limitation of the applicability of 3-BrPA to GBM therapy is its inability to cross the blood-brain barrier.18 A second molecule for targeting aerobic glycolysis is dichloroacetate (DCA), which inhibits the mitochondrial enzyme pyruvate dehydrogenase kinase (PDK).19 PDK is a direct inhibitor of pyruvate dehydrogenase (PDH), which regulates the passage of pyruvate into mitochondria. Through the inhibition of an inhibitor, therefore, DCA promotes mitochondrial oxidation and decreases lactic acid formation.19 In essence, DCA promotes the aerobic metabolism of glucose through the tricarboxylic acid (TCA) cycle and oxidative phosphorylation, in place of the conversion of pyruvate into lactate. Due to the widespread distribution of oral DCA in the central nervous system,20,21 its efficacy at inhibiting growth in several GBM cell lines has been investigated.6 DCA led to rapid reversal of mitochondrial hyperpolarization in GBM cells (a marker of an apoptosis-resistant state), promoted p53 activation, and suppressed angiogenesis. In a trial of 3 participants with recurrent GBMs and 2 with primary GBMs, DCA was administered, in addition to standard chemotherapeutic and radiation protocols, and found to possibly be associated with prolonged radiological regression and stabilization. The dose of DCA, however, was limited by reversible peripheral neuropathy. Peripheral nerve toxicity had previously been noted during in vivo and human studies involving disorders of lactic acidosis.22,23 Due to the reported inability of 3-BrPA to cross the blood-brain barrier and the dose-limiting toxicity of DCA, we set out to establish whether these molecules could be safely and effectively delivered locally at the tumor site. To maximize clinical relevancy, we selected a proven, FDA-approved method of local drug release using the biodegradable polyanhydride, poly-(1,3 bis[p-carboxyphenoxy] propane-co-sebacic acid) (p[CPP:SA, 20:80]).24 P(CPP:SA, 20:80) has been shown to be biocompatible in the brain with no evidence of systemic or local toxicity. In multiple glioma studies no difference in survival has been noted between groups receiving empty p(CPP:SA) wafers and untreated animals.25,26 We present the tolerability and efficacy of locally delivered 3-BrPA and DCA via p(CPP:SA, 20:80) polymer wafer. We then investigate the combination of 3-BrPA and DCA with temozolomide and radiation therapy.

Object The aim of this study was to demonstrate that paclitaxel could function as a radiosensitizer for malignant glioma in vitro and in vivo. Methods The radiosensitizing effect of paclitaxel was tested in vitro using the human U373MG and rat 9L glioma cell lines. Cell cycle arrest in response to paclitaxel exposure was quantified by flow cytometry. Cells were subsequently irradiated, and toxicity was measured using the clonogenic assay. In vivo studies were performed in Fischer 344 rats implanted with intracranial 9L gliosarcoma. Rats were treated with control polymer implants, paclitaxel controlled-release polymers, radiotherapy, or a combination of the 2 treatments. The study end point was survival. Results Flow cytometry demonstrated G2-M arrest in both U373MG and 9L cells following 6–12 hours of paclitaxel exposure. The order in which the combination treatment was administered was significant. Exposure to radiation treatment (XRT) during the 6–12 hours after paclitaxel treatment resulted in a synergistic reduction in colony formation. This effect was greater than the effect from either treatment alone and was also greater than the effect of radiation exposure followed by paclitaxel. Rats bearing 9L gliosarcoma tumors treated with paclitaxel polymer administration followed by single-fraction radiotherapy demonstrated a synergistic improvement in survival compared with any other treatment, including radiotherapy followed by paclitaxel treatment. Median survival for control animals was 13 days; for those treated with paclitaxel alone, 21 days; for those treated with XRT alone, 21 days; for those treated with XRT followed by paclitaxel, 45 days; and for those treated with paclitaxel followed by XRT, more than 150 days (p < 0.0001). Conclusions These results indicate that paclitaxel is an effective radiosensitizer for malignant gliomas because it renders glioma cells more sensitive to ionizing radiation by causing G2-M arrest, and induces a synergistic response to chemoradiotherapy.

Object The poor outcome of malignant gliomas is largely due to local invasiveness. Previous studies suggest that gliomas secrete excess glutamate and destroy surrounding normal peritumoral brain by means of excitotoxic mechanisms. In this study the authors assessed the effect on survival of 2 glutamate modulators (riluzole and memantine) in rodent glioma models. Methods In an in vitro growth inhibition assay, F98 and 9L cells were exposed to riluzole and memantine. Mouse cerebellar organotypic cultures were implanted with F98 glioma cells and treated with radiation, radiation + riluzole, or vehicle and assessed for tumor growth. Safety and tolerability of intracranially implanted riluzole and memantine CPP:SA polymers were tested in F344 rats. The efficacy of these drugs was tested against the 9L model and riluzole was further tested with and without radiation therapy (RT). Results In vitro assays showed effective growth inhibition of both drugs on F98 and 9L cell lines. F98 organotypic cultures showed reduced growth of tumors treated with radiation and riluzole in comparison with untreated cultures or cultures treated with radiation or riluzole alone. Three separate efficacy experiments all showed that localized delivery of riluzole or memantine is efficacious against the 9L gliosarcoma tumor in vivo. Systemic riluzole monotherapy was ineffective; however, riluzole given with RT resulted in improved survival. Conclusions Riluzole and memantine can be safely and effectively delivered intracranially via polymer in rat glioma models. Both drugs demonstrate efficacy against the 9L gliosarcoma and F98 glioma in vitro and in vivo. Although systemic riluzole proved ineffective in increasing survival, riluzole acted synergistically with radiation and increased survival compared with RT or riluzole alone.

Background and Purpose— Extravascular optical coherence tomography (OCT), as a noninvasive imaging methodology with micrometer resolution, was evaluated in a murine model of carotid atherosclerosis by way of assessing the efficacy of pravastatin therapy. Methods— An OCT device was engineered for extravascular plaque imaging. Wild-type mice and apolipoprotein E–deficient (ApoE −/− ) mice were randomized to 3 treatment groups: (1) wild-type on a diet of standard rodent chow (n=13); (2) ApoE −/− on a high-fat, atherosclerotic diet (HFD; n=13); and (3) ApoE −/− on a HFD given daily pravastatin (n=13). Mice were anesthetized and the left common carotid was surgically exposed. Three-dimensional (3D; 2 spatial dimensions+time) and 4D (3 spatial dimensions+time) OCT images of the vessel lumen patency were evaluated. After perfusion, in situ OCT imaging was performed for statistical comparison with the in vivo results and final histology. Results— Intraoperative OCT imaging positively identified carotid plaque in 100% of ApoE −/− mice on HFD. ApoE −/− mice on HFD had a significantly decreased lumen patency when compared with that in wild-type mice ( P −/− mice on HFD ( P −/− on HFD). The findings were confirmed with OCT imaging after perfusion and histology. Conclusions— OCT imaging offers the potential for real-time, detailed vessel lumen evaluation, potentially improving surgical accuracy and outcomes during cerebrovascular neurosurgical procedures. Pravastatin significantly increases vessel lumen patency in the ApoE −/− mouse on HFD.

Object Over the past several years, there has been increasing interest in combining angiogenesis inhibitors with radiotherapy and temozolomide chemotherapy in the treatment of glioblastoma. Although the US FDA approved bevacizumab for the treatment of glioblastoma in 2009, the European Medicines Agency rejected its use due to its questionable impact on patient survival. One factor contributing to the failure of angiogenesis inhibitors to increase overall patient survival may be their inability to cross the blood-brain barrier. Here the authors examined in a 9L glioma model whether intracranial polymer-based delivery of the angiogenesis inhibitor minocycline potentiates the effects of both radiotherapy and temozolomide chemotherapy in increasing median survival. The authors also investigated whether the relative timing of minocycline polymer implantation with respect to radiotherapy affects the efficacy of radiotherapy. Methods Minocycline was incorporated into the biodegradable polymer polyanhydride poly(1,3-bis-[p-carboxyphenoxy propane]-co-[sebacic anhydride]) (CPP:SA) at a ratio of 50:50 by weight. Female Fischer 344 rats were implanted with 9L glioma on Day 0. The minocycline polymer was then implanted on either Day 3 or Day 5 posttumor implantation. Cohorts of rats were exposed to 20 Gy focal radiation on Day 5 or were administered oral temozolomide (50 mg/kg daily) on Days 5–9. Results Both minocycline polymer implantations on Days 3 and 5 increased survival from 14 days to 19 days (p < 0.001 vs control). Treatment with a combination of both minocycline polymer and radiotherapy on Day 5 resulted in a 139% increase in median survival compared with treatment with radiotherapy alone (p < 0.005). There was not a statistically significant difference in median survival between the group that received minocycline implanted on the same day as radiotherapy and the group that received minocycline polymer 2 days prior to radiotherapy. Lastly, treatment with a combination of minocycline polymer with oral temozolomide resulted in a 38% extension of median survival compared with treatment of oral temozolomide alone (p < 0.001). Conclusions These results show that minocycline delivered locally potentiates the effects of both radiotherapy and oral temozolomide in increasing median survival in a rodent glioma model. More generally, these results suggest that traditional therapy in combination with local, as opposed to systemic, delivery of angiogenesis inhibitors may be able to increase median survival for patients with glioblastoma.

Background: The change in the reaction time of a tail or paw exposed to a thermal stimulus is a measure of nociceptive activity in laboratory animals. Tail-flick and plantar thermal sensitivity (Hargreaves) tests are non-invasive, minimize stress, and can be used to screen animals for phenotype and drug activity. Objective: Hargreaves testing has been widely used in rats. We investigated its use to measure the activity of opiate analgesia in mice. Methods: Mice were used in thermal stimulus studies at 1-5 hours and 1-5 days to test acute and extended release preparations of buprenorphine. Results: Hargreaves testing had limited value at 1-5 hours because mice can have an obtunded response to opiate therapy. Tail-flick studies with restrained mice are not affected by the initial locomotor stimulation. Discussion: The present report describes a simple restraint system for mice. The utility of the system is demonstrated by examining the efficacy of acute and extended release buprenorphine injections in Balb/c and Swiss mice. Conclusion: Standardized tail-flick testing provides a sensitive robust method to monitor opiate activity in mice.

Background: Long-acting therapy in laboratory animals offers advantages over the current practice of 2-3 daily drug injections. Yet little is known about the disintegration of biodegradable drug implants in rodents. Objective: Compare bioavailability of buprenorphine with the biodegradation of lipid-encapsulated subcutaneous drug pellets. Methods: Pharmacokinetic and histopathology studies were conducted in BALB/c female mice implanted with cholesterol-buprenorphine drug pellets. Results: Drug levels are below the level of detection (0.5 ng/mL plasma) within 4-5 days of implant. However, necroscopy revealed that interstitial tissues begin to seal implants within a week. Visual inspection of the implant site revealed no evidence of inflammation or edema associated with the cholesterol-drug residue. Chemical analyses demonstrated that the residues contained 10-13% of the initial opiate dose for at least two weeks post implant. Discussion: The results demonstrate that biodegradable scaffolds can become sequestered in the subcutaneous space. Conclusion: Drug implants can retain significant and unintended reservoirs of drugs.

There has been considerable interest in repurposing the poly ADP ribose polymerase inhibitor and purported radiosensitiser olaparib (Lynparza), with a recent dose escalation study of olaparib plus temozolomide in recurrent GBM showing good tolerance (Fulton et al 2018). Due to systemic therapy-associated caveats such as dose-limiting toxicities and blood-brain-barrier penetration, here we assess localised post-surgical delivery of olaparib from our previously developed poly(DL-lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) (PLGA/PEG) thermo-sensitive biodegradable paste. Metabolic and clonogenic assays revealed impaired proliferation and clonal growth respectively, upon acute exposure of high-grade glioma cells to olaparib (3–5µM), an effect dramatically potentiated with 3Gy radiation. Flow cytometry of Annexin V+/Propidium iodide+ rodent and human high-grade glioma cells, revealed a significant cell proportion increase at late stage apoptosis when exposed to 2–3µM olaparib and 3Gy radiation (relative to untreated, olaparib alone or radiation alone). A high-grade glioma orthotopic allograft study is ongoing where we already observe a significant overall survival benefit of locally-delivered 10% and 20% w/w (drug:polymer ratio) olaparib via PLGA/PEG paste post-surgery with adjuvant radiotherapy, compared to surgery/oral temozolomide/radiotherapy (GBM standard-of-care) and surgery/systemic olaparib (120 days vs. 44 vs 30 respectively). A more pronounced survival benefit, as determined by the total number of long-term surviving animals, was observed with combined PLGA/PEG/olaparib/temozolomide/radiotherapy or PLGA/PEG/olaparib/etoposide/radiotherapy. RNAseq data from 10 GBM patients show significantly elevated levels of apoptosis-inducing factor-1 in 5-aminolevulinic acid (5ALA)+ fluorescence–activated cell sorted populations (i.e. purified tumour cells from the invasive margin), relative to 5ALA- cells, confirming PARP-1 activity in infiltrative tumour cells. Collectively our data supports a clinical rationale for localised olaparib delivery with adjuvant radiotherapy.

Medulloblastoma (MB), an aggressive pediatric brain malignancy, is commonly classified into four subtypes. Although survival has improved remarkably, Group 3 and Shh-driven tumors still experience high rates of recurrent and metastatic disease. Disulfiram (DSF), a safe and inexpensive drug, has shown an antitumor effect when administered with copper (Cu++) against other brain malignancies, and its repurposing to MB could benefit current standards of treatment. ONS76 (Shh-driven Tp53 wild-type), UW228 (Shh-driven Tp53-mutated), D425med and D341med (Group 3) lines were treated with DSF-Cu++and tested with viability, proliferation and clonogenic assays. Flow cytometry (FACS) with AnnexinV-PI, Ki67, PI/RNAse for necrosis and cell cycle, and CD133 and Aldefluor for cell-stemness were carried out. MB lines were tested with western blotting (WB) and immunofluorescence (IF) for NPL4(Nuclear protein localization protein 4 homolog), AIF (apoptosis-inducing factor), cleaved-PARP(Poly-ADP-ribose-polymerase), H2AX and other molecular targets. In vivo safety (n=8) and efficacy studies (n=16) were carried out on Nu/Nu athymic mice implanted intracranially (IC) with D425med cells, along with Hematoxylin/Eosin and immunohistochemistry analyses on brain samples. DSF-Cu++showed remarkable cytotoxic and anti-proliferative activity against all MB lines. In particular, NPL4, a protein involved in the ubiquitin signaling, appears to be the primary DSF target, as previously shown in other malignancies. Apoptosis quickly follows the Heat-Shock Response, as confirmed by FACS, WB and IF, and cell-stemness is decreased significantly by nanomolar doses of DSF-Cu++(p=0.002). Oral administration of DSF-Cu++was proven safe at doses of 100 mg/kg and significantly prolonged survival in IC xenografts (median 28.5 days; p=0.02) compared to controls (median 24 days). DSF, a compound used in the treatment of chronic alcoholism, has recently shown a remarkable effect in a number of malignancies when co-administered with Cu++. We provide proof of its potential as a chemotherapeutic for pediatric MB, and describe its molecular mechanism of action.

Purpose: Nasopharyngeal carcinoma (NPC) is a squamous cell carcinoma that is often diagnosed at an advanced stage, leading to poor disease-free and overall survival. Accumulating literature suggests that elevated protein expression of EZH2, eIF4E, and IMPDH correlates with poor prognosis in NPC. These three proteins are modulated by the FDA-approved antiviral drug ribavirin, which has recently been repurposed by our laboratory and others as a promising anti-cancer agent. Based on this intersection of molecular signature and drug targets, we investigated the potential use of ribavirin as a therapeutic agent for NPC. Experimental Design: We assessed anti-neoplastic efficacy of ribavirin on human NPC cell lines in vitro using cellular growth assays, flow cytometry, and scratch wound assays. Mechanistic pathways involved were investigated using genomic expression datasets, western blots, and enzymatic activity assays. The effects of combining ribavirin with radiation were assessed via clonogenic assays and flow cytometry. Finally, we evaluated the effects of ribavirin on tumor growth in vivo using human cell line-derived xenograft models. Results: Ribavirin significantly decreased NPC cellular proliferation and migratory capacity in addition to promoting cell cycle arrest and cell death. Modulation of the EZH2, Snail, eIF4E, and IMPDH pathways was observed in response to ribavirin treatment. Ribavirin significantly enhanced the cytotoxic effects of radiation therapy in NPC. Most importantly, ribavirin significantly reduced flank tumor growth in NPC xenograft models. Conclusions: Our work suggests that ribavirin has potent anti-cancer effects in NPC and could represent a safe and promising addition to current NPC treatment regimens. Citation Format: Andy S. Ding, Joshua Casaos, Sakibul Huq, Henry Brem, Nicolas Skuli, Betty Tyler. Repurposing the FDA-approved antiviral drug ribavirin as targeted therapy for nasopharyngeal carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2190.

Anti-angiogenic agents, such as bevacizumab (BEV), can induce normalization of the blood brain barrier, which may influence the penetration and activity of a co-administered cytotoxic drug. However, it is unknown whether this effect is associated with a benefit in overall survival. This study employed intracranial human glioma models to evaluate the effect of BEV alone and in combination with temozolomide (TMZ) and/or radiation therapy (XRT) on overall survival. One hundred eight male athymic rats were intracranially injected with either U251 or U87 human glioma. Ten or eleven days after tumor inoculation, animals bearing U251 and U87, respectively, were treated with: TMZ alone (50 mg/kg for 5 consecutive days, P.O.), BEV alone (15 mg/kg, I.V.), a combination of TMZ and BEV, or a combination of TMZ, BEV, and a single fraction of XRT (20 Gy). Controls received no treatment. The U87 experiment was repeated and the relationship between survival and the extent of anti-angiogenesis via anti-laminin antibodies for the detection of blood vessels was assessed. In both U87 glioma experiments, all of the treatment groups had a statistically significant increase in survival as compared to the control groups. Also, for both U87 experiments the combination groups of TMZ and BEV had significantly better survival when compared to either treatment administered alone, with 75 % of animals demonstrating long-term survival (LTS) (defined as animals alive 120 days after tumor implantation) in one experiment and 25 % LTS in the repeat experiment. In the U251 glioma experiment, all treated groups (except BEV alone) had significantly improved survival as compared to controls with minimal statistical variance among groups. The percent vessel area was lowest in the group of animals treated with BEV alone. The addition of BEV to TMZ and/or XRT had variable effect on prolonging survival in the two human glioma models tested with reduced tumor vascularity in groups treated with BEV. These results indicate that BEV has anti-angiogenic activity and does not seem to hinder the effect of TMZ.

Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults, and radiation is one of the main treatment modalities. However, cure rates remain low despite best available therapies. Immunotherapy is a promising modality that could work synergistically with radiation, which has been shown to increase antigen presentation and promote a proinflammatory tumor microenvironment. Programmed-death-1 (PD-1) is a surface receptor expressed on activated and exhausted T cells, which mediate T cell inhibition upon binding with its ligand PD-L1, expressed on many tumor types including human GBMs. We tested the combination of anti-PD-1 immunotherapy with stereotactic radiosurgery in a mouse orthotopic GBM model.We performed intracranial implantation of mouse glioma cell line GL261 transfected with luciferase into C57BL/6 mice. Mice were stratified into 4 treatment groups: (1) control; (2) radiation only; (3) anti-PD-1 antibody only; and (4) radiation plus anti-PD-1 antibody. Overall survival was quantified. The mice were killed on day 21 after implantation to assess immunologic parameters in the brain/tumor, cervical lymph nodes, and spleen.Improved survival was demonstrated with combination anti-PD-1 therapy plus radiation compared with either modality alone: median survival was 25 days in the control arm, 27 days in the anti-PD-1 antibody arm, 28 days in the radiation arm, and 53 days in the radiation plus anti-PD-1 therapy arm (P.05 by log-rank Mantle-Cox). Long-term survival was seen only in the combined treatment arm, with a fraction (15%-40%) of animals alive at day 180+ after treatment. Immunologic data on day 21 after implantation showed increased tumor infiltration by cytotoxic T cells (CD8+/interferon-γ+/tumor necrosis factor-α+) and decreased regulatory T cells (CD4+/FOXP3) in the combined treatment group compared with the single modality arms.The combination of PD-1 blockade and localized radiation therapy results in long-term survival in mice with orthotopic brain tumors. These studies provide strong preclinical evidence to support combination trials in patients with GBM.

The immunosuppressive effects of chemotherapy present a challenge for designing effective cancer immunotherapy strategies. We hypothesized that although systemic chemotherapy (SC) exhibits negative immunologic effects, local chemotherapy (LC) can potentiate an antitumor immune response. We show that LC combined with anti–programmed cell death protein 1 (PD-1) facilitates an antitumor immune response and improves survival (P < 0.001) in glioblastoma. LC-treated mice had increased infiltration of tumor-associated dendritic cells and clonal expansion of antigen-specific T effector cells. In comparison, SC resulted in systemic and intratumoral lymphodepletion, with decreased immune memory in long-term survivors. Furthermore, adoptive transfer of CD8+ cells from LC-treated mice partially rescued SC-treated mice after tumor rechallenge. Last, the timing of chemo- and immunotherapy had differential effects on anti–PD-1 efficacy. This study suggests that both mode of delivery and timing have distinct effects on the efficacy of anti–PD-1. The results of this work could help guide the selection and scheduling of combination treatment for patients with glioblastoma and other tumor types.

Background Glioblastoma (GBM) is a poorly immunogenic neoplasm treated with focused radiation. Immunotherapy has demonstrated synergistic survival effects with stereotactic radiosurgery (SRS) in murine GBM. GITR is a co-stimulatory molecule expressed constitutively on regulatory T-cells and by effector T-cells upon activation. We tested the hypothesis that anti-GITR monoclonal antibody (mAb) and SRS together would confer an immune-mediated survival benefit in glioma using the orthotopic GL261 glioma model. Methods Mice received SRS and anti-GITR 10 days after implantation. The anti-GITR mAbs tested were formatted as mouse IgG1 D265A (anti-GITR (1)) and IgG2a (anti-GITR (2a)) isotypes. Mice were randomized to four treatment groups: (1) control; (2) SRS; (3) anti-GITR; (4) anti-GITR/SRS. SRS was delivered to the tumor in one fraction, and mice were treated with mAb thrice. Mice were euthanized on day 21 to analyze the immunologic profile of tumor, spleen, and tumor draining lymph nodes. Results Anti-GITR (1)/SRS significantly improved survival over either treatment alone (p

Purpose: Checkpoint molecules like programmed death-1 (PD-1) and T-cell immunoglobulin mucin-3 (TIM-3) are negative immune regulators that may be upregulated in the setting of glioblastoma multiforme. Combined PD-1 blockade and stereotactic radiosurgery (SRS) have been shown to improve antitumor immunity and produce long-term survivors in a murine glioma model. However, tumor-infiltrating lymphocytes (TIL) can express multiple checkpoints, and expression of ≥2 checkpoints corresponds to a more exhausted T-cell phenotype. We investigate TIM-3 expression in a glioma model and the antitumor efficacy of TIM-3 blockade alone and in combination with anti-PD-1 and SRS.Experimental Design: C57BL/6 mice were implanted with murine glioma cell line GL261-luc2 and randomized into 8 treatment arms: (i) control, (ii) SRS, (iii) anti-PD-1 antibody, (iv) anti-TIM-3 antibody, (v) anti-PD-1 + SRS, (vi) anti-TIM-3 + SRS, (vii) anti-PD-1 + anti-TIM-3, and (viii) anti-PD-1 + anti-TIM-3 + SRS. Survival and immune activation were assessed.Results: Dual therapy with anti-TIM-3 antibody + SRS or anti-TIM-3 + anti-PD-1 improved survival compared with anti-TIM-3 antibody alone. Triple therapy resulted in 100% overall survival (P < 0.05), a significant improvement compared with other arms. Long-term survivors demonstrated increased immune cell infiltration and activity and immune memory. Finally, positive staining for TIM-3 was detected in 7 of 8 human GBM samples.Conclusions: This is the first preclinical investigation on the effects of dual PD-1 and TIM-3 blockade with radiation. We also demonstrate the presence of TIM-3 in human glioblastoma multiforme and provide preclinical evidence for a novel treatment combination that can potentially result in long-term glioma survival and constitutes a novel immunotherapeutic strategy for the treatment of glioblastoma multiforme. Clin Cancer Res; 23(1); 124–36. ©2016 AACR.

The median survival for glioblastoma patients is ~15 months despite aggressive surgery and radio-chemotherapy approaches. Thus, developing new therapeutics is necessary to improve the treatment of these invasive brain tumors, which are known to show high levels of the eukaryotic initiation factor, eIF4E, a potent oncogene. Ribavirin, the only clinically approved drug known to target eIF4E, is an anti-viral molecule currently used in hepatitis C treatment. Here, we report the effect of ribavirin on proliferation, cell cycle, cell death and migration of several human and murine glioma cell lines, as well as human glioblastoma stem-like cells, in vitro. In addition, we tested ribavirin efficacy in vivo, alone and in combination with temozolomide and radiation. Our work showed that ribavirin inhibits glioma cell growth and migration, and increases cell cycle arrest and cell death, potentially through modulation of the eIF4E, EZH2 and ERK pathways. We also demonstrate that ribavirin treatment in combination with temozolomide or irradiation increases cell death in glioma cells. Finally and most importantly, ribavirin treatment in vivo significantly enhances chemo-radiotherapy efficacy and improves survival of rats and mice orthotopically implanted with gliosarcoma tumors or glioma stem-like cells, respectively. On the basis of these results, we propose that ribavirin represents a new therapeutic option for glioblastoma patients as an enhancer of the cytotoxic effects of temozolomide and radiotherapy.

Glioblastoma (GBM) is a poorly immunogenic neoplasm treated with focused radiation. Immunotherapy has demonstrated synergistic survival effects with stereotactic radiosurgery (SRS) in murine GBM. GITR is a co-stimulatory molecule expressed constitutively on regulatory T-cells and by effector T-cells upon activation. We tested the hypothesis that anti-GITR monoclonal antibody (mAb) and SRS together would confer an immune-mediated survival benefit in glioma using the orthotopic GL261 glioma model. Mice received SRS and anti-GITR 10 days after implantation. The anti-GITR mAbs tested were formatted as mouse IgG1 D265A (anti-GITR (1)) and IgG2a (anti-GITR (2a)) isotypes. Mice were randomized to four treatment groups: (1) control; (2) SRS; (3) anti-GITR; (4) anti-GITR/SRS. SRS was delivered to the tumor in one fraction, and mice were treated with mAb thrice. Mice were euthanized on day 21 to analyze the immunologic profile of tumor, spleen, and tumor draining lymph nodes. Anti-GITR (1)/SRS significantly improved survival over either treatment alone (p

The cranial window preparation provides optical access to the rodent brain for high-resolution in vivo optical imaging. Two types of cranial windows are commonly employed, namely the open-skull window and thinned-skull window. Chronic in vivo laser speckle contrast imaging (LSCI) through the cranial window permits characterization of neurovascular morphology and blood flow changes over days or weeks. However, the effects of window type and their long-term stability for in vivo LSCI have not been studied. Here we systematically characterize the effect of each cranial window type on in vivo neurovascular monitoring with LSCI over two weeks. Imaging outcomes for each window were assessed in terms of contrast-to-noise ratio (CNR), microvessel density (MVD) and total vessel length (TVL). We found that the thinned-skull window required a shorter recovery period (~ 4 days), provided a larger field of view and was a good choice for short-term (i.e. < 10 days) in vivo imaging, but not for the long term because of the confounding effects of skull regrowth after ten days. The open-skull window required a longer recovery period, as made evident by the decrease in window quality within the 10-day period. In spite of this, the open-skull window would be preferable for chronic (i.e. < 10 days) in vivo imaging applications. Overall, this study informs about the pros and cons of each cranial window type for LSCI-based neurovascular imaging.

After over 50 years of scientific contribution under the leadership of Harvey Cushing and later Walter Dandy, the Johns Hopkins Hunterian Laboratory entered a period of dormancy between the 1960s and early 1980s. In 1984, Henry Brem reinstituted the Hunterian Neurosurgical Laboratory, with a new focus on localized delivery of therapies for brain tumors, leading to several discoveries such as new antiangiogenic agents and Gliadel chemotherapy wafers for the treatment of malignant gliomas. Since that time, it has been the training ground for 310 trainees who have dedicated their time to scientific exploration in the lab, resulting in numerous discoveries in the area of neurosurgical research. The Hunterian Neurosurgical Laboratory has been a unique example of successful mentoring in a translational research environment. The laboratory's philosophy emphasizes mentorship, independence, self-directed learning, creativity, and people-centered collaboration, while maintaining productivity with a focus on improving clinical outcomes. This focus has been served by the diverse backgrounds of its trainees, both in regard to educational status as well as culturally. Through this philosophy and strong legacy of scientific contribution, the Hunterian Laboratory has maintained a positive and productive research environment that supports highly motivated students and trainees. In this article, the authors discuss the laboratory's training philosophy, linked to the principles of adult learning (andragogy), as well as the successes and the limitations of including a wide educational range of students in a neurosurgical translational laboratory and the phenomenon of combining clinical expertise with rigorous scientific training.

Quaternized derivatives of pectic galactan (QPG) were synthesized by a reaction of pectic galactan (PG) with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC) in the presence of aqueous sodium hydroxide solution under mild reaction conditions. The results showed that the concentration of CHPTAC and NaOH has great impact on the quaternization reaction. QPG was found to interact electrostatically with plasmid DNA in aqueous solution to form complexes in globular condensed morphology in a nanometer scale size ranging from 60 to 160nm. Complexes formed with QPG fluorescently labeled with 5-DTAF (QPG-5-DTAF) were introduced to the C6 rat glioma cell line, and were found to be able to enter the cell and approach the nucleus within 24h. The results suggest that this type of modified natural polysaccharide may have an advantage as a biocompatible and biodegradable gene delivery carrier and furthermore may serve as a cell specific carrier.

There is a need for enabling non-viral nanobiotechnology to allow safe and effective gene therapy and cell therapy, which can be utilized to treat devastating diseases such as brain cancer. Human adipose-derived mesenchymal stem cells (hAMSCs) display high anti-glioma tropism and represent a promising delivery vehicle for targeted brain tumor therapy. In this study, we demonstrate that non-viral, biodegradable polymeric nanoparticles (NPs) can be used to engineer hAMSCs with higher efficacy (75% of cells) than leading commercially available reagents and high cell viability. To accomplish this, we engineered a poly(beta-amino ester) (PBAE) polymer structure to transfect hAMSCs with significantly higher efficacy than Lipofectamine™ 2000. We then assessed the ability of NP-engineered hAMSCs to deliver bone morphogenetic protein 4 (BMP4), which has been shown to have a novel therapeutic effect by targeting human brain tumor initiating cells (BTIC), a source of cancer recurrence, in a human primary malignant glioma model. We demonstrated that hAMSCs genetically engineered with polymeric nanoparticles containing BMP4 plasmid DNA (BMP4/NP-hAMSCs) secrete BMP4 growth factor while maintaining their multipotency and preserving their migration and invasion capacities. We also showed that this approach can overcome a central challenge for brain therapeutics, overcoming the blood brain barrier, by demonstrating that NP-engineered hAMSCs can migrate to the brain and penetrate the brain tumor after both intranasal and systemic intravenous administration. Critically, athymic rats bearing human primary BTIC-derived tumors and treated intranasally with BMP4/NP-hAMSCs showed significantly improved survival compared to those treated with control GFP/NP-hAMCSs. This study demonstrates that synthetic polymeric nanoparticles are a safe and effective approach for stem cell-based cancer-targeting therapies.

Purpose: Glioblastoma multiforme (GBM) remains highly incurable, with frequent recurrences after standard therapies of maximal surgical resection, radiation, and chemotherapy. To address the need for new treatments, we have undertaken a chimeric antigen receptor (CAR) “designer T cell” (dTc) immunotherapeutic strategy by exploiting interleukin (IL)13 receptor α-2 (IL13Rα2) as a GBM-selective target. Experimental Design: We tested a second-generation IL13 “zetakine” CAR composed of a mutated IL13 extracellular domain linked to intracellular signaling elements of the CD28 costimulatory molecule and CD3ζ. The aim of the mutation (IL13.E13K.R109K) was to enhance selectivity of the CAR for recognition and killing of IL13Rα2+ GBMs while sparing normal cells bearing the composite IL13Rα1/IL4Rα receptor. Results: Our aim was partially realized with improved recognition of tumor and reduced but persisting activity against normal tissue IL13Rα1+ cells by the IL13.E13K.R109K CAR. We show that these IL13 dTcs were efficient in killing IL13Rα2+ glioma cell targets with abundant secretion of cytokines IL2 and IFNγ, and they displayed enhanced tumor-induced expansion versus control unmodified T cells in vitro. In an in vivo test with a human glioma xenograft model, single intracranial injections of IL13 dTc into tumor sites resulted in marked increases in animal survivals. Conclusions: These data raise the possibility of immune targeting of diffusely invasive GBM cells either via dTc infusion into resection cavities to prevent GBM recurrence or via direct stereotactic injection of dTcs to suppress inoperable or recurrent tumors. Systemic administration of these IL13 dTc could be complicated by reaction against normal tissues expressing IL13Ra1. Clin Cancer Res; 18(21); 5949–60. ©2012 AACR.

Primary malignant brain tumors (BT) are the most common and aggressive malignant brain tumor. Treatment of BTs is a daunting task with median survival just at 21 months. Methods of localized delivery have achieved success in treating BT by circumventing the blood brain barrier and achieving high concentrations of therapeutic within the tumor. The capabilities of localized delivery can be enhanced by utilizing mirco-electro-mechanical systems (MEMS) technology to deliver drugs with precise temporal control over release kinetics. An intracranial MEMS based device was developed to deliver the clinically utilized chemotherapeutic temozolomide (TMZ) in a rodent glioma model. The device is a liquid crystalline polymer reservoir, capped by a MEMS microchip. The microchip contains three nitride membranes that can be independently ruptured at any point during or after implantation. The kinetics of TMZ release were validated and quantified in vitro. The safety of implanting the device intracranially was confirmed with preliminary in vivo studies. The impact of TMZ release kinetics was investigated by conducting in vivo studies that compared the effects of drug release rates and timing on animal survival. TMZ delivered from the device was effective at prolonging animal survival in a 9L rodent glioma model. Immunohistological analysis confirmed that TMZ was released in a viable, cytotoxic form. The results from the in vivo efficacy studies indicate that early, rapid delivery of TMZ from the device results in the most prolonged animal survival. The ability to actively control the rate and timing of drug(s) release holds tremendous potential for the treatment of BTs and related diseases.

Object Brain tumors pose many unique challenges to treatment. The authors hypothesized that Fc-endostatin may be beneficial. It is a newly synthesized recombinant human endostatin conjugated to the Fc domain of IgG with a long half-life (weeks) and unknown toxicity. The authors examined the efficacy of Fc-endostatin using various delivery methods. Methods Efficacy was assessed using the intracranial 9L gliosarcoma rat model treated with Fc-endostatin for use in rodents (mFc-endostatin), which was administered either systemically or locally via different delivery methods. Oral temozolomide (TMZ) was administered in combination with mFc-endostatin to determine if there was a beneficial synergistic effect. Results Intracranial delivery of mFc-endostatin via a polymer or convection-enhanced delivery 5 days after tumor implantation increased median survival, compared with the control group (p = 0.0048 and 0.003, respectively). Animals treated weekly with subcutaneous mFc-endostatin (started 5 days post–tumor implantation) also had statistically improved survival as compared with controls (p = 0.0008). However, there was no statistical difference in survival between the local and systemic delivery groups. Control animals had a median survival of 13 days. Animals treated either with subcutaneous mFc-endostatin weekly or with polymer had a median survival of 18 and 15 days, respectively, and those treated with oral TMZ for 5 days (Days 5–9) had a median survival of 21 days. Survival was further increased with a combination of oral TMZ and mFc-endostatin polymer, with a median survival of 28 days (p = 0.029, compared with TMZ alone). Subcutaneous mFc-endostatin administered every week starting 18 days before tumor implantation significantly increased median survival when compared with controls (p = 0.0007), with 12.5% of the animals ultimately becoming long-term survivors (that is, survival longer than 120 days). The addition of TMZ to either weekly or daily subcutaneous mFc-endostatin and its administration 18 days before tumor implantation significantly increased survival (p = 0.017 and 0.0001, respectively, compared with TMZ alone). Note that 12.5% of the animals treated with weekly subcutaneous mFc-endostatin and TMZ were long-term survivors. Conclusions Systemically or directly (local) delivered mFc-endostatin prolonged the survival of rats implanted with intracranial 9L gliosarcoma. This benefit was further enhanced when mFc-endostatin was combined with the oral chemotherapeutic agent TMZ.

ObjectTreatment options for anaplastic or malignant intramedullary spinal cord tumors (IMSCTs) remain limited. Paclitaxel has potent cytotoxicity against experimental intracranial gliomas and could be beneficial in the treatment of IMSCTs, but poor CNS penetration and significant toxicity limit its use. Such limitations could be overcome with local intratumoral delivery. Paclitaxel has been previously incorporated into a biodegradable gel depot delivery system (OncoGel) and in this study the authors evaluated the safety of intramedullary injections of OncoGel in rats and its efficacy against an intramedullary rat gliosarcoma.MethodsSafety of intramedullary OncoGel was tested in 12 Fischer-344 rats using OncoGel concentrations of 1.5 and 6.0 mg/ml (5 μl); median survival and functional motor scores (Basso-Beattie-Bresnahan [BBB] scale) were compared with those obtained with placebo (ReGel) and medium-only injections. Efficacy of OncoGel was tested in 61 Fischer-344 rats implanted with an intramedullary injection of 9L gliosarcoma containing 100,000 cells in 5 μl of medium, and randomized to receive OncoGel administered on the same day (in 32 rats) or 5 days after tumor implantation (in 29 rats) using either 1.5 mg/ml or 3.0 mg/ml doses of paclitaxel. Median survival and BBB scores were compared with those of ReGel-treated and tumor-only rats. Animals were killed after the onset of deficits for histopathological analysis.ResultsOncoGel was safe for intramedullary injection in rats in doses up to 5 μl of 3.0 mg/ml of paclitaxel; a dose of 5 μl of 6.0 mg/ml caused rapid deterioration in BBB scores. OncoGel at concentrations of 1.5 mg/ml and 3.0 mg/ml paclitaxel given on both Day 0 and Day 5 prolonged median survival and preserved BBB scores compared with controls. OncoGel 1.5 mg/ml produced 62.5% long-term survivors when delivered on Day 0. A comparison between the 1.5 mg/ml and the 3.0 mg/ml doses showed higher median survival with the 1.5 mg/ml dose on Day 0, and no differences in median survival or BBB scores after treatment on Day 5.ConclusionsOncoGel is safe for intramedullary injection in rats in doses up to 5 μl of 3.0 mg/ml, prolongs median survival, and increases functional motor scores in rats challenged with an intramedullary gliosarcoma at the doses tested. This study suggests that locally delivered chemotherapeutic agents could be of temporary benefit in the treatment of malignant IMSCTs under experimental settings.

The treatment of intracranial malignancies is lim- ited by the ability of systemically administered therapies to cross the blood-brain barrier. Royer resorbable matrix, or R- Gel, is a dextran polymer administered in liquid form via nee- dle injection. Within minutes of preparation, the polymer forms a gel and subsequently solidifies, thereby conforming to the dimensions of the injection cavity. R-Gel can accom- modate a wide variety of therapeutic agents that may provide new options for local treatment delivery. This preclinical study evaluates the neurotoxicity of R-Gel implanted in the rat brain. Fifteen rats underwent intracranial administration of R-Gel (N ¼ 9) or saline (N ¼ 6) were monitored for sys- temic and neurotoxicity, and sacrificed at pre-determined time points. Animals that received the R-Gel injection demon- strated no behavioral changes or weight loss. Histopathologic analysis revealed an inflammatory response in both groups on day 3 and day 7 after implantation, which resolved by day 42. These results suggest that intracranial R-Gel is well toler- ated. Therapeutic studies of chemotherapy-complexed R-Gel are underway. V

Leptomeningeal carcinomatosis (LC) is a devastating complication of cancer. Intrathecal administration of cytotoxic chemotherapy adds little to survival which is measured in weeks. The potential toxicities and efficacy of intrathecally administered anti-angiogenic agents in this setting have not previously been explored. A well-characterized animal model was used to evaluate the neurotoxicity of intraventricularly administered bevacizumab (BCM). Thirty-three New Zealand White Rabbits were studied. Subcutaneous reservoirs and ventricular catheters (SRVC) were placed in eight rabbits, which were randomized to receive weekly intraventricular saline with or without BCM for four weeks. These rabbits were euthanized on day 36 and the brains were examined by a blinded neuropathologist. Twenty-five additional rabbits underwent cisternal injection of VX2 carcinoma cells with or without a single dose of BCM and were followed for survival. No clinical manifestations of neurotoxicity were noted in rabbits treated with intraventricular BCM. Similarly, no evidence of BCM neurotoxicity was identified in autopsied animals. The median survival of evaluable rabbits with LC treated with intraventricular saline (N = 13) was 15 days compared to 18 days for the animals receiving VX2 and one dose of BCM (N = 12). Conclusion: Intraventricular BCM can be administered to rabbits without clinical or pathologic neurotoxicity. Survival following one dose of BCM in rabbits with LC should be cautiously interpreted given uncertainties regarding the dose, schedule, and limited expected benefit of this non-rabbit antibody. This neurotoxicity study provides safety data to allow phase I/II studies in humans with treatment refractory LC.

Rapamycin, an anti-proliferative agent, is effective in the treatment of renal cell carcinoma and recurrent breast cancers. We proposed that this potent mammalian target of rapamycin inhibitor may be useful for the treatment of gliomas as well. We examined the cytotoxicity of rapamycin against a rodent glioma cell line, determined the toxicity of rapamycin when delivered intracranially, and investigated the efficacy of local delivery of rapamycin for the treatment of experimental malignant glioma in vivo. We also examined the dose-dependent efficacy of rapamycin and the effect when locally delivered rapamycin was combined with radiation therapy. Rapamycin was cytotoxic to 9L cells, causing 34% growth inhibition at a concentration of 0.01 µg/mL. No in vivo toxicity was observed when rapamycin was incorporated into biodegradable caprolactone-glycolide (35:65) polymer beads at 0.3%, 3%, and 30% loading doses and implanted intracranially. Three separate efficacy studies were performed to test the reproducibility of the effect of the rapamycin beads as well as the validity of this treatment approach. Animals treated with the highest dose of rapamycin beads tested (30%) consistently demonstrated significantly longer survival durations than the control and placebo groups. All dose-escalating rapamycin bead treatment groups (0.3%, 3% and 30%), treated both concurrently with tumor and in a delayed manner after tumor placement, experienced a significant increase in survival, compared with controls. Radiation therapy in addition to the simultaneous treatment with 30% rapamycin beads led to significantly longer survival duration than either therapy alone. These results suggest that the local delivery of rapamycin for the treatment of gliomas should be further investigated.

INTRODUCTION: We previously developed a humanized mouse model of chordomas, which allowed us to investigate the interaction between human chordomas and human immune cells. This platform is particularly useful for studying immunotherapy against rare cancers such as chordomas, where murine equivalents are currently unavailable. We aim to utilize this model to study synergism between PD-1 blockade and LXR-623, a synthetic agonist of liverX receptors, a class of anti-neoplastic agents disrupting cancer cholesterol-metabolism. Our preliminary data suggest that LXR-623 downregulates PD-L1 on chordoma cell lines and reduces immunosuppressive myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment. METHODS: To achieve immune system reconstitution/humanization, 20 NSG-SGM3 mice were engrafted with human fetal thymus and CD34+ stem cells, whose HLA-types were partially-matched with those of the U-CH1 chordoma cell lines. They were divided into the following groups (n=5 for each group): control group (isotype antibodies (Abs) + vehicle), LXR-623 monotherapy group (isotype Abs + LXR-623 100mg/kg, i.p., daily for 4 weeks), anti-PD-1 Abs monotherapy group (anti-human-PD-1-Abs (Clone: J116), 10 mg/kg, i.p., 3 times/week for 4 weeks), and combination group (anti-human-PD-1 Abs + LXR-623). Anti-tumor activities will be monitored via tumor size measurement, flow cytometric analyses of peripheral blood and spleen as well as chordomas, using various Abs including anti-mouse-CD45, anti-human-CD3, anti-human-CD4, anti-human-CD8, anti-human-CD11b, anti-human-CD14, anti-human-CD15, anti-human-CD19, anti-human-CD25, anti-human-CD45, anti-human-CD45RA, anti-human-CD45RO, anti-human-PD-1, and anti-human-FoxP3, multiplex cytokine analyses including IFN-gamma and TGF-beta, and multiplex-immunohistochemistry. We expect to observe the synergistic inhibitory effect of LXR-623 and anti-PD1-Abs against chordomas through PD-L1 downregulation and reduction in immunosuppressive MDSC levels mediated by LXR-623. We plan to sacrifice the last animal group on August 24th. Due to the lengthy nature of the experiment (humanization and treatment take 13–14 weeks), the data are not fully available at the time of submission but will be available by the late-breaking deadline.

Object Paclitaxel, a cellular proliferation inhibitor/radiation sensitizer, while effective against gliomas in vitro, has poor CNS penetration and dose-limiting toxicities when administered systemically. OncoGel (paclitaxel in Re-Gel) provides controlled local paclitaxel release when placed into the CNS. The authors evaluated the safety and efficacy of OncoGel in rats with intracranial 9L gliosarcoma. Methods Safety studies included intracranial delivery of increasing volumes of ReGel and OncoGel containing 1.5 (OncoGel 1.5) or 6.3 (OncoGel 6.3) mg/ml paclitaxel. An in vivo radiolabeled biodistribution study was performed in 18 Fischer-344 rats to determine intracerebral distribution. Efficacy studies compared overall survival for controls, ReGel only, radiation therapy only, OncoGel 6.3, or OncoGel 6.3 in combination with radiation therapy. ReGel and OncoGel 6.3 were delivered either simultaneously with tumor implantation (Day 0) or 5 days later (Day 5). Radiation therapy was given on Day 5. Results Control and ReGel animals died of tumor within 17 days. Survival significantly increased in the Onco-Gel 6.3 group on Day 0 (median 31 days; p = 0.0001), in the OncoGel 6.3 group on Day 5 (median 17 days; p = 0.02), and in the radiation therapy–only group (median 26 days; p = 0.0001) compared with controls. Animals receiving both OncoGel and radiation therapy had the longest median survival: 83 days in the group with radiation therapy combined with OncoGel 6.3 on Day 0, and 32 days in the group combined with OncoGel 6.3 on Day 5 (p = 0.0001 vs controls). After 120 days, 37.5% of the animals in the OncoGel Day 0 group, 37.5% of animals in the OncoGel 6.3 Day 0 in combination with radiation therapy group, and 12.5% of the animals in the OncoGel 6.3 on Day 5 in combination with radiation therapy group were alive. In the biodistribution study, measurable radioactivity was observed throughout the ipsilateral hemisphere up to 3 weeks after the OncoGel injection, with the most radioactivity detected 3 hours after injection. The highest dose of radioactivity observed in the contralateral hemisphere was at the Day 3 time point. Conclusions OncoGel containing 6.3 mg/ml of paclitaxel is safe for intracranial injection in rats and effective when administered on Day 0. When combined with radiation therapy, the combination was more effective than either therapy alone and should be studied clinically for the treatment of malignant glioma.

Object Diffuse brainstem tumors are the most difficult type of pediatric CNS malignancy to treat. These inoperable lesions are treated with radiation alone or in combination with chemotherapy, and the survival rate is less than 10%. It is therefore essential to develop a reliable animal model to screen new therapeutic agents for the treatment of this type of tumor. Methods A multipotent human glioblastoma stemlike neurosphere line, 060919, was established from a surgically resected glioblastoma specimen; when cells were implanted intracranially into athymic nude mice, they formed invasive, vascular tumors that exhibited the features of glioblastoma. Ten female Fischer 344 rats received an injection of 75,000 F98 rat glioma cells and 10 female athymic nude rats received an injection of 75,000 060919 human glioblastoma stemlike cells in the pontine tegmentum of the brainstem. A control group of 5 female Fischer rats received an injection of saline in the same location as the animals in the tumor groups. Kaplan-Meier curves were generated for survival, and brains were processed postmortem for histopathological investigation. Results Both F98 cells and 060919 cells grew in 100% of the animals injected. Median survival of animals injected with F98 was 15 days, consistent with the authors' previous reports on the establishment of the brainstem tumor model using the F98 rat glioma line. Median survival of animals injected with 060919 was 31 days. Histopathological analysis of the tumors confirmed the presence of brainstem lesions in animals that received brainstem injections of F98 and in animals that received brainstem injections of 060919. The 060919 brainstem tumors histologically resembled glioblastoma. Conclusions Tumor take and median survival were consistent for animals injected in the brainstem with either the established F98 rat glioma cell line or the 060919 human glioblastoma stemlike neurosphere line. Histopathological features of the 060919 brainstem tumors resembled glioblastoma. Establishment of this human glioblastoma stemlike brainstem animal model will improve the evaluation and identification of more efficacious agents for the treatment of high-grade brainstem tumors.

The homeobox transcription factor OTX2 plays an essential role during embryonic brain development. It is normally silenced in the adult brain, but is overexpressed by genomic amplification or other mechanisms in the majority of medulloblastomas (MBs). Retinoic acids (RAs) can suppress OTX2 expression and inhibit MB growth. In this study, 9-cis RA most potently inhibited MB cell growth. 9-cis RA functions through the downregulation of OTX2 expression, which subsequently induces neuronal differentiation of OTX2-expressing cells. Treatment with 9-cis RA reduced the growth of D425 flank xenograft tumors in mice. In an intracranial model, however, MB tumors showed resistance to 9-cis RA treatment, and we implicated fibroblast growth factor (FGF) as a potential mediator of resistance to RA therapy. These findings suggest a mechanism for RA-mediated anti-tumor effect on OTX2-positive MB cells and indicate that therapeutic targeting of OTX2 might be effective if FGF pathway-mediated resistance can be overcome.

Antineoplastic RNAse proteins, also known as Amphibinases, have been shown effective against various solid tumors but were found selectively neurotoxic to Purkinje cells in the cerebellum. This work describes the use of a waxy biodegradable poly(ricinoleic-co-sebacic acid) for the local controlled delivery of cytotoxic amphibinases in the parietal lobe of the brain in an attempt to overcome cerebellar neuronal toxicity while affecting glioma cells.Amphibinase analogues were encapsulated in poly(ricinoleic-co-sebacic acid) formulations using mix-melt technology and loaded onto surgical foam. In-vitro release was monitored by BCA colorimetry and by RNAse specific bioactivity. The implants were inserted into rat brains bearing 9L glioma to assess toxicity and efficacy.The various formulations showed extended linear release for several weeks with minimal burst effect. Best in-vivo efficacy was obtained with ACC7201 containing implants, resulting in the extension of the median survival from 13 to 18 days with 13% long-term survivors.Antineoplastic proteins were released from a p(SA-RA) polyanhydride implants in a controlled manner, providing efficacy against 9L glioma, while evading neurotoxicity in the cerebellum. The controlled release of Amphibinases forms the potential for a new therapy against brain tumors.

Convection-enhanced delivery using carboplatin in brainstem glioma models was reported to prolong survival. Functional impairment is of additional importance to evaluate the value of local chemotherapy. We established a neurological scoring system for the rat brainstem glioma model.In 46 male Fisher rats stereotactically 10(5) F-98 cells were implanted at 1.4-mm lateral to midline and at the lambdoid suture using guided screws. Following 4 days local delivery was performed using Alzet pumps (1 microl/h over 7 days) with either vehicle (5% dextrose) or carboplatin via one or two cannulas, respectively. All rats were subsequently tested neurologically using a specified neurological score. In 38 animals survival time was recorded. Representative MR imaging were acquired in eight rats, respectively, at day 12 after implantation. HE staining was used to evaluate tumor extension.Neurological scoring showed significantly higher impairment in the high dose carboplatin group during the treatment period. Survival was significantly prolonged compared to control animals in the high dose carboplatin-one cannula group as well as in both low dose carboplatin groups (18.6 +/- 3 versus 26.3 +/- 9, 22.8 +/- 2, 23.6 +/- 2 days; p0.05). Overall neurological grading correlated with survival time. MR imaging showed a focal contrast enhancing mass in the pontine brainstem, which was less exaggerated after local chemotherapy. Histological slices visualized decreased cellular density in treatment animals versus controls.Local chemotherapy in the brainstem glioma model showed significant efficacy for histological changes and survival. Our neurological grading enables quantification of drug and tumor-related morbidity as an important factor for functional performance during therapy.

Technical aspects of local chemotherapy in inoperable brainstem gliomas by convection-enhanced delivery (CED) are still under experimental considerations. In this study, we characterize the feasibility of multiple cannula placements in the rat brainstem.In 38 male Fisher rats, up to three guided screws were positioned in burr holes paramedian at 2.5 mm anterior and posterior to as well as at the lambdoid suture. Using Alzettrade mark pumps (1 microl/h flow rate over 7 days) either vehicle (5% dextrose) or 0.1 mg carboplatin was delivered via one, two, or three cannulas, respectively. During cannula insertion, electrocardiogram and respiratory rate was monitored. All rats were subsequently evaluated neurologically for 8 days. For drug distribution in coronal sections, the brain tissue concentration of platinum was measured. HE staining was used to evaluate the local site of drug delivery. Heart and respiratory rate remained within normal range during surgical procedure. Neurological scoring showed only mild neurological impairment in the groups receiving two or three cannulas, which resolved after vehicle delivery. However, after carboplatin delivery, this deficit remained unchanged. Drug distribution was more homogeneous in the three cannula group. Histological slices visualized edematous changes at the sight of cannula placement.The unilateral application of up to three cannulas in the brainstem of rats for local drug delivery studies is feasible. The remaining neurological deficit in carboplatin-treated animals underlines the need of low toxicity drugs for CED in the brainstem.

Sustained local delivery of single agents and controlled delivery of multiple chemotherapeutic agents are sought for the treatment of brain cancer. A resorbable, multi-reservoir polymer microchip drug delivery system has been tested against a tumor model. The microchip reservoirs were loaded with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). BCNU was more stable at 37 °C within the microchip compared to a uniformly impregnated polymeric wafer (70% intact drug vs. 38%, at 48 h). The half-life of the intact free drug in the microchip was 11 days, which is a marked enhancement compared to its half-life in normal saline and 10% ethanol (7 and 10 min, respectively) [P. Tepe, S.J. Hassenbusch, R. Benoit, J.H. Anderson, BCNU stability as a function of ethanol concentration and temperature, J. Neurooncol. 10 (1991) 121–127; P. Kari, W.R. McConnell, J.M. Finkel, D.L. Hill, Distribution of Bratton–Marshall-positive material in mice following intravenous injections of nitrosoureas, Cancer Chemother. Pharmacol. 4 (1980) 243–248]. A syngeneic Fischer 344 9L gliosarcoma rat model was used to study the tumoricidal efficacy of BCNU delivery from the microchip or homogeneous polymer wafer. A dose-dependent decrease in tumor size was found for 0.17, 0.67, and 1.24 mg BCNU-microchips. Tumors treated with 1.24 mg BCNU-microchips showed significant tumor reduction (p = 0.001) compared to empty control microchips at two weeks. The treatment showed similar efficacy to a polymer wafer with the same dosage. The microchip reservoir array may enable delivery of multiple drugs with independent release kinetics and formulations.

Meeting abstracts Glioblastoma, despite the use of radiation and chemotherapy, remains vastly lethal. Cancer immunotherapy has entered the era of maturity with new compounds like anti-PD-1 FDA approved to treat advanced tumors. However, the use of immunotherapy in the setting of chemotherapy

This work investigated the efficacy of intracranial delivery of acriflavine (ACF), a small-molecule hypoxia-inducible factor 1α (HIF-1α) therapeutic inhibitor, for the treatment of primary brain malignancies. ACF, a mixture of two closely related acridine molecules, has only recently been recognized as a potent hypoxia-inducible factor 1α (HIF-1α) inhibitor, but has already demonstrated highly effective anti-tumor activity against a wide spectrum of cancers. Thus far, no study has reported its efficacy in either glioma cell lines or brain tumor models. In our in vitro study on rodent and human glioma cell lines, we showed that ACF suppressed cell viability and increased cell death in a dose-dependent manner. Our in vivo study examined the safety and efficacy of locally delivered ACF in monotherapy. To overcome ACF's poor systemic bioavailability and limited BBB penetration, we delivered ACF directly to the site of the tumor via biodegradable polymer wafers. Throughout three separate experiments, enrolling a total of 60 F334 Fisher rats, we showed that animals receiving local implantation of ACF wafers achieved an extraordinary 100% survival rate of up to 300 days (p

INTRODUCTION: Checkpoint molecules like programmed death-1 (PD-1) and T cell immunoglobulin mucin-3 (TIM-3) act as negative regulators of the immune system and can be upregulated in the setting of glioblastoma multiforme (GBM). Combined PD-1 blockade and stereotactic radiosurgery (SRS) have been shown to improve antitumor immunity and produces long-term survivors in a murine glioma model.1 However, tumor infiltrating lymphocytes can express multiple checkpoints (including TIM-3), and expression of ≥2 checkpoints corresponds to a more exhausted T cell phenotype.2 It was therefore hypothesized that the addition of a second checkpoint-blocking antibody could achieve additive or synergistic antitumor effects. METHODS: C57BL/6 mice were implanted with mouse glioma cell line GL261 transfected with luciferase and randomized into 8 treatment arms: (1) control, (2) SRS, (3) anti-PD-1 antibody, (4) anti-TIM-3 antibody, (5) anti-PD-1 + SRS, (6) anti-TIM-3 + SRS, (7) anti-PD-1 + anti-TIM-3, and (8) anti-PD-1 + anti-TIM-3 + SRS. Overall survival was measured. Brain, cervical lymph nodes, and peripheral blood were harvested on day 21 to assess immune activation. RESULTS: Survival benefits were observed with combined anti-TIM-3 antibody + SRS compared to anti-TIM-3 antibody alone with a median survival (MS) of 69 vs. 25 days and overall survival (OS) of 50% vs. 0%, respectively (p < 0.001 by log-rank Mantel-Cox). Dual blockade with anti-TIM-3 + anti-PD-1 antibody also improved survival compared to TIM-3 blockade alone, (MS of 100 vs. 25 days, OS 60% vs. 0%, respectively, p < 0.05). Notably, OS in the triple therapy group (anti-PD-1 + anti-TIM-3 + SRS) was 100% by day 100 (p < 0.05), a significant improvement compared to all other treatment arms. Flow cytometry of organs harvested on day 21 showed that compared to the dual therapy groups, mice treated with triple therapy had increased tumor infiltration by interferon-gamma+ (IFNg) and tumor necrosis factor-alpha+ (TNFa)-producing CD4+ T cells, as well as IFNg+ CD8+ lymphocytes. CONCLUSIONS: Combining anti-TIM-3 with anti-PD-1 and radiation was synergistic and conferred a significant survival benefit.

Radiotherapy remains a major treatment method for malignant tumors. Magnetic resonance imaging (MRI) is the standard modality for assessing glioma treatment response in the clinic. Compared to MRI, ultrasound imaging is low-cost and portable and can be used during intraoperative procedures. The purpose of this study was to quantitatively compare contrast-enhanced ultrasound (CEUS) imaging and MRI of irradiated gliomas in rats and to determine which quantitative ultrasound imaging parameters can be used for the assessment of early response to radiation in glioma.Thirteen nude rats with U87 glioma were used. A small thinned skull window preparation was performed to facilitate ultrasound imaging and mimic intraoperative procedures. Both CEUS and MRI with structural, functional, and molecular imaging parameters were performed at preradiation and at 1 day and 4 days postradiation. Statistical analysis was performed to determine the correlations between MRI and CEUS parameters and the changes between pre- and postradiation imaging.Area under the curve (AUC) in CEUS showed significant difference between preradiation and 4 days postradiation, along with four MRI parameters, T2, apparent diffusion coefficient, cerebral blood flow, and amide proton transfer-weighted (APTw) (all p0.05). The APTw signal was correlated with three CEUS parameters, rise time (r = - 0.527, p0.05), time to peak (r = - 0.501, p0.05), and perfusion index (r = 458, p0.05). Cerebral blood flow was correlated with rise time (r = - 0.589, p0.01) and time to peak (r = - 0.543, p0.05).MRI can be used for the assessment of radiotherapy treatment response and CEUS with AUC as a new technique and can also be one of the assessment methods for early response to radiation in glioma.