Enriched environment reduces glioma growth through immune and non-immune mechanisms in mice

Mice exposed to standard (SE) or enriched environment (EE) were transplanted with murine or human glioma cells and differences in tumour development were evaluated. We report that EE exposure affects: (i) tumour size, increasing mice survival; (ii) glioma establishment, proliferation and invasion; (iii) microglia/macrophage (M/Mφ) activation; (iv) natural killer (NK) cell infiltration and activation; and (v) cerebral levels of IL-15 and BDNF. Direct infusion of IL-15 or BDNF in the brain of mice transplanted with glioma significantly reduces tumour growth. We demonstrate that brain infusion of IL-15 increases the frequency of NK cell infiltrating the tumour and that NK cell depletion reduces the efficacy of EE and IL-15 on tumour size and of EE on mice survival. BDNF infusion reduces M/Mφ infiltration and CD68 immunoreactivity in tumour mass and reduces glioma migration inhibiting the small G protein RhoA through the truncated TrkB.T1 receptor. These results suggest alternative approaches for glioma treatment

Genetically Engineered T-Cells for Malignant Glioma: Overcoming the Barriers to Effective Immunotherapy.

Malignant gliomas carry a dismal prognosis. Conventional treatment using chemo- and radiotherapy has limited efficacy with adverse events. Therapy with genetically engineered T-cells, such as chimeric antigen receptor (CAR) T-cells, may represent a promising approach to improve patient outcomes owing to their potential ability to attack highly infiltrative tumors in a tumor-specific manner and possible persistence of the adaptive immune response. However, the unique anatomical features of the brain and susceptibility of this organ to irreversible tissue damage have made immunotherapy especially challenging in the setting of glioma. With safety concerns in mind, multiple teams have initiated clinical trials using CAR T-cells in glioma patients. The valuable lessons learnt from those trials highlight critical areas for further improvement: tackling the issues of the antigen presentation and T-cell homing in the brain, immunosuppression in the glioma microenvironment, antigen heterogeneity and off-tumor toxicity, and the adaptation of existing clinical therapies to reflect the intricacies of immune response in the brain. This review summarizes the up-to-date clinical outcomes of CAR T-cell clinical trials in glioma patients and examines the most pressing hurdles limiting the efficacy of these therapies. Furthermore, this review uses these hurdles as a framework upon which to evaluate cutting-edge pre-clinical strategies aiming to overcome those barriers

Efficacy of Combined 5-Fluorouracil and Photodynamic Therapy in Glioma Spheroids

Standard treatment regimens consisting of surgery, radiation and chemotherapy have proven ineffective for the treatment of high-grade gliomas such as glioblastoma multiforme (GBM). An effective cure requires elimination of nests of tumor cells that have migrated from the resection margin and infiltrated normal brain. A number of localized therapies, including light-based approaches such as photodynamic therapy (PDT) and photochemical internalization (PCI) are currently under investigation for the management of GBM patients. Several studies have demonstrated a high degree of synergy between PDT and bleomycin, via the PCI mechanism, in a variety of in vitro and in vivo models, including glioma cell lines. The purpose of this study was to examine the efficacy of combined treatments consisting of PDT and the chemotherapeutic agent, 5-fluorouracil (5-FU) in a 3-dimensional spheroid model consisting of F98 rat glioma cells. Spheroids were incubated with a photosensitizer (aluminum phthalocyanine disulfonate; AlPcS2a) and irradiated with 670 nm laser light. Three different wash protocols (0, 4 and 24 h) were employed to determine whether any observed interactions between PDT and 5-FU could be attributed to the PCI mechanism, or were simply due to different cytotoxic pathways of the two treatment modalities. Although the combined PDT + 5-FU treatments resulted in greater suppression of spheroid growth compared to either treatment alone, no statistically significant differences in growth effects were observed between 0 and 4 h wash protocols suggesting that the combined treatment effects were due to different mechanisms of cytotoxicity, rather than a PCI effect

Novel therapeutic venues for glioblastoma: novel rising preclinical treatment opportunities

High grade gliomas, including anaplastic glioma WHO grade III and glioblastoma WHO IV (GBM), carry a dismal prognosis. Taking all nowadays-available therapeutics options, including radiation, chemotherapy and surgery, for GBM into consideration the prognosis after initial diagnosis is about 12 month. Despite this bad prognosis, researchers gained a tremendous insight into the molecular and genetic signatures of low and high grade gliomas. Several different subtypes of GBM were demonstrated with respect to their genetic background. These genetic alterations include p53 mutation in secondary GBMs and EGFR amplification in primary GBMs, respectively. Very recently, great excitement was raised after the discovery of IDH1 mutation in low-grade gliomas and secondary GBMs. This discovery is of great significance since it allows further categorizing of GBMs and is helpful in distinguishing low-grade gliomas from non-neoplastic adjacent brain tissue. Despite all this progress there is an urgent need for fresh additional therapeutic strategies. In addition to the identification of novel therapeutic regimens it is of utmost importance to gain an understanding about the molecular mechanisms on how GBMs manage to evade from almost any anti-cancer treatment regimen. In experimental models of glioblastoma there are a number of novel therapeutic regimens that exhibited promising results. These novel therapeutics include, but are not limited to: Apoptosis-based therapeutics (Tumor necrosis factor alpha related apoptosis inducing ligand, TRAIL), tyrosinkinase-inhibitors, Heat-shock-protein 90 (HSP90) inhibitors, polyphenols, novel drug combinations and intracranial application based strategies. This chapter will primarily review and focus on molecular mechanisms of resistance in GBM and rising new therapeutic venues for high-grade gliomas. High-grade gliomas are a group of primary heterogenous tumors of which glioblastoma World Health Organisation, WHO IV (GBM), is the most common one. Once the diagnosis of GBM is made, the average survival time is approximately 12-15 month (Hegi, Diserens et al., 2005). Treatment usually consists of temozolomide (commonly used chemotherapeutic drug for the treatment of GBM, TMZ), radiation (either alone or in combination with chemotherapeutics) and surgery (Hegi, Diserens et al., 2005)..

Injectable diblock copolypeptide hydrogel provides platform to maintain high local concentrations of taxol and local tumor control

Abstract Introduction Surgical resection and systemic chemotherapy with temozolomide remain the mainstay for treatment of glioblastoma. However, many patients are not candidates for surgical resection given inaccessible tumor location or poor health status. Furthermore, despite being first line treatment, temozolomide has only limited efficacy. Methods The development of injectable hydrogel-based carrier systems allows for the delivery of a wide range of chemotherapeutics that can achieve high local concentrations, thus potentially avoiding systemic side effects and wide-spread neurotoxicity. To test this modality in a realistic environment, we developed a diblock copolypeptide hydrogel (DCH) capable of carrying and releasing paclitaxel, a compound that we found to be highly potent against primary gliomasphere cells. Results The DCH produced minimal tissue reactivity and was well tolerated in the immune-competent mouse brain. Paclitaxel-loaded hydrogel induced less tissue damage, cellular inflammation and reactive astrocytes than cremaphor-taxol (typical taxol-carrier) or hydrogel alone. In a deep subcortical xenograft model, of glioblastoma in immunodeficient mice, injection of paclitaxel-loaded hydrogel led to a high local concentration of paclitaxel and led to local tumor control and improved survival. However, the tumor cells were highly migratory and were able to eventually escape the area of treatment. Conclusions These findings suggest this technology may be ultimately applicable to patients with deep-seated inoperable tumors, but as currently formulated, complete tumor eradication would be highly unlikely. Future studies should focus on targeting the migratory potential of surviving cells

Mathematical Model of the Impact of Chemotherapy and Anti-Angiogenic Therapy on Drug Resistance in Glioma Growth

This research presents a mathematical model of glioma growth dynamics with drug resistance, capturing interactions among five cell populations: glial cells, sensitive glioma cells, resistant glioma cells, endothelial cells, and neuron cells, along with two therapy agent populations: chemotherapy and anti-angiogenic therapy. Glioma is a malignant tumor originating from glial cells, undergoes chemotherapy-induced mutations, leading to drug-resistant glioma cells. This not only impacts glioma cells but also normal cells. Combining chemotherapy and anti-angiogenic therapy, the model employs a Holling type II response function, considering optimal dosages for treatment optimization. Through analysis, three equilibrium are identified: two stable and one unstable equilibrium points. Numerical simulations, employing phase portraits and trajectory diagrams, illustrate the combined therapies impact on glioma cells. In summary, this concise model explores glioma dynamics and drug resistance, offering insights into the efficacy of combined therapies, crucial for optimizing glioma treatment

Immunocompetent murine models for the study of glioblastoma immunotherapy.

Glioblastoma remains a lethal diagnosis with a 5-year survival rate of less than 10%. (NEJM 352:987-96, 2005) Although immunotherapy-based approaches are capable of inducing detectable immune responses against tumor-specific antigens, improvements in clinical outcomes are modest, in no small part due to tumor-induced immunosuppressive mechanisms that promote immune escape and immuno-resistance. Immunotherapeutic strategies aimed at bolstering the immune response while neutralizing immunosuppression will play a critical role in improving treatment outcomes for glioblastoma patients. In vivo murine models of glioma provide an invaluable resource to achieving that end, and their use is an essential part of the preclinical workup for novel therapeutics that need to be tested in animal models prior to testing experimental therapies in patients. In this article, we review five contemporary immunocompetent mouse models, GL261 (C57BL/6), GL26 (C57BL/6) CT-2A (C57BL/6), SMA-560 (VM/Dk), and 4C8 (B6D2F1), each of which offer a suitable platform for testing novel immunotherapeutic approaches

Depression and anxiety in glioma patients

Glioma patients carry the burden of having both a progressive neurological disease and cancer, and may face a variety of symptoms, including depression and anxiety. These symptoms are highly prevalent in glioma patients (median point prevalence ranging from 16-41% for depression and 24-48% for anxiety when assessed by self-report questionnaires) and have a major impact on health-related quality of life and even overall survival time. A worse overall survival time for glioma patients with depressive symptoms might be due to tumor progression and/or its supportive treatment causing depressive symptoms, an increased risk of suicide or other (unknown) factors. Much is still unclear about the etiology of depressive and anxiety symptoms in glioma. These psychiatric symptoms often find their cause in a combination of neurophysiological and psychological factors, such as the tumor and/or its treatment. Although these patients have a particular idiosyncrasy, standard treatment guidelines for depressive and anxiety disorders apply, generally recommending psychological and pharmacological treatment. Only a few nonpharmacological trials have been conducted evaluating the efficacy of psychological treatments (eg, a reminiscence therapy-based care program) in this population, which significantly reduced depressive and anxiety symptoms. No pharmacological trials have been conducted in glioma patients specifically. More well-designed trials evaluating the efficacy of nonpharmacological treatments for depressive and anxiety disorders in glioma are urgently needed to successfully treat psychiatric symptoms in brain tumor patients and to improve (health-related) quality of life