Remodelling and Treatment of the Blood-Brain Barrier in Glioma

Blood-oxygenation-level-dependent (BOLD) MRI responses to CO2 and O2 inhalation in brain gliomas

PURPOSE

Cerebrovascular abnormalities are intricately involved in gliomas. While static cerebrovascular properties such as cerebral blood flow, volume, and permeability have been extensively studied, dynamic vascular parameters have not been fully understood. This study aimed to characterize the vascular responses to CO2 and O2 inhalation in brain gliomas.

METHODS

In 15 glioma patients, concomitant CO2 and O2 inhalation was applied while BOLD MR images were continuously acquired for nine minutes, resulting in the measurement of O2-reactivity, CO2-reactivity, and bolus arrival time (BAT). Vascular parameters were compared between the tumor regions and contralateral healthy tissue using Student t-tests. The dependence of vascular parameters on glioma grade, glioma subtypes, and molecular biomarkers were assessed using a multiple linear regression.

RESULTS

Visual inspection suggested that reliable O2-reactivity, CO2-reactivity, and BAT maps could be obtained in every patient. Compared to the contralateral healthy tissue, glioma regions on average revealed a diminished O2-reactivity (p < 0.001) and CO2-reactivity (p < 0.001), but a lengthened BAT (p < 0.001). Intra-tumoral heterogeneity in the vascular parameters between core and periphery was also observed. Astrocytomas had a lower CO2-reactivity (p = 0.014) and a longer BAT (p = 0.012) relative to oligodendrogliomas. Glioma grade had no association with O2-reactivity, CO2-reactivity, or BAT. Patients who lost ATRX expression had a lower CO2- and O2-reactivity (p = 0.005 and p = 0.035) compared to patients who retained ATRX expression.

CONCLUSIONS

Gliomas are associated with abnormal CO2- and O2-reactivity measured with MRI. These dynamic parameters may provide new insights into the vascular pathophysiology in gliomas.

Ion channel expression and function in glioblastoma multiforme (GBM): pathophysiological mechanisms and therapeutic potential

Glioblastoma Multiforme (GBM) is a highly malignant and diffusely invasive WHO Grade IV brain tumor arising from glial and neural stem cells. GBM is characterized by rapid proliferation and migration, aggressive invasion of local brain parenchyma, a hypoxic microenvironment, resistance to apoptosis and high vascular remodeling and angiogenesis. These hallmarks contribute to a near universal tumor recurrence after treatment or resection and poor patient prognosis. Ion channels, a superfamily of proteins responsible for permitting ion flux across otherwise impermeant membranes, show extensive remodeling in GBM with aberrant function mechanistically linked to manipulation of each of these hallmarks. In this review, we will discuss the known links between ion channel expression and activity and cellular processes that are enhanced or perturbed during GBM formation or progression. We will also discuss the extent to which basic or translational findings on ion channels in GBM samples or cell lines have shown preclinical promise towards the development of improved therapeutics against GBMs.

Carbon-Encapsulated Iron Nanoparticles Seeking Integrins in Murine Glioma

Purpose

Targeting integrin receptors for MRI represents a novel method in diagnosing glioblastoma. In the present study carbon-encapsulated iron nanoparticles to explore murine glioma tracking based upon specific direct targeting with monoclonal antibodies against the beta-3 subunit (CD61) of the integrin αVβ3 receptor are described.

Methods

The carbon arc discharge method was used to synthesize nanoparticles and amidation-type reaction were applied to attach monoclonal antibody (anti-CD61) with acidic group functionalized nanoparticles to lead two types of bioconjugates (Fe@C-CONH-anti-CD61 and Fe@C-(CH2)2-CONH-anti-CD61). The as-synthesized bioconjugates were tested on murine glioma cells (GL261) using MTT, LDH and calcein AM/propidium iodide assays. Relaxometry measurements were performed with a 1.5 T (63 MHz) MRI scanner using both GL261 cells and C57BL/6 mice bearing GL261 tumors.

Results

The results showed that Fe@C-CONH-anti-CD61 and Fe@C-(CH2)2-CONH-anti-CD61 nanoparticles have higher binding affinity towards GL261 cells compared to pristine nanoparticles without antibodies. Studies evidenced that the antibody-decorated nanoparticles did not produce any severe cytotoxic effects on murine glioma cells. Preclinical MRI studies demonstrated that the Fe@C-(CH2)2-CONH-anti-CD61 nanoparticle-based construct specifically targeted murine glioma in animals.

Conclusion

The carbon-encapsulated iron nanoparticles functionalized with monoclonal antibodies recognizing the beta-3 subunit of the integrin αVβ3 receptor can be considered as a potential contrast agent for MRI-based tracking glioblastoma.

Plant Alkaloids as Promising Anticancer Compounds with Blood-Brain Barrier Penetration in the Treatment of Glioblastoma: In Vitro and In Vivo Models

Glioblastoma (GBM) is one of the most invasive central nervous system tumors, with rising global incidence. Therapy resistance and poor prognosis highlight the urgent need for new anticancer drugs. Plant alkaloids, a largely unexplored yet promising class of compounds, have previously contributed to oncology treatments. While past reviews provided selective insights, this review aims to collectively compare data from the last decade on (1) plant alkaloid-based anticancer drugs, (2) alkaloid transport across the blood-brain barrier (BBB) in vitro and in vivo, (3) alkaloid mechanisms of action in glioblastoma models (in vitro, in vivo, ex vivo, and in silico), and (4) cytotoxicity and safety profiles. Additionally, innovative drug delivery systems (e.g., nanoparticles and liposomes) are discussed. Focusing on preclinical studies of single plant alkaloids, this review includes 22 botanical families and 28 alkaloids that demonstrated anti-GBM activity. Most alkaloids act in a concentration-dependent manner by (1) reducing glioma cell viability, (2) suppressing proliferation, (3) inhibiting migration and invasion, (4) inducing cell death, (5) downregulating Bcl-2 and key signaling pathways, (6) exhibiting antiangiogenic effects, (7) reducing tumor weight, and (8) improving survival rates. The toxic and adverse effect analysis suggests that alkaloids such as noscapine, lycorine, capsaicin, chelerythrine, caffeine, boldine, and colchicine show favorable therapeutic potential. However, tetrandrine, nitidine, harmine, harmaline, cyclopamine, cocaine, and brucine may pose greater risks than benefits. Piperine's toxicity and berberine's poor bioavailability suggest the need for novel drug formulations. Several alkaloids (kukoamine A, cyclovirobuxine D, α-solanine, oxymatrine, rutaecarpine, and evodiamine) require further pharmacological and toxicological evaluation. Overall, while plant alkaloids show promise in glioblastoma therapy, progress in assessing their BBB penetration remains limited. More comprehensive studies integrating glioma research and advanced drug delivery technologies are needed.

Unlocking the therapeutic potential of tumor-derived EVs in ischemia-reperfusion: a breakthrough perspective from glioma and stroke

Clinical studies have revealed a bidirectional relationship between glioma and ischemic stroke, with evidence of spatial overlap between the two conditions. This connection arises from significant similarities in their pathological processes, including the regulation of cellular metabolism, inflammation, coagulation, hypoxia, angiogenesis, and neural repair, all of which involve common biological factors. A significant shared feature of both diseases is the crucial role of extracellular vesicles (EVs) in mediating intercellular communication. Extracellular vesicles, with their characteristic bilayer structure, encapsulate proteins, lipids, and nucleic acids, shielding them from enzymatic degradation by ribonucleases, deoxyribonucleases, and proteases. This structural protection facilitates long-distance intercellular communication in multicellular organisms. In gliomas, EVs are pivotal in intracranial signaling and shaping the tumor microenvironment. Importantly, the cargos carried by glioma-derived EVs closely align with the biological factors involved in ischemic stroke, underscoring the substantial impact of glioma on stroke pathology, particularly through the crucial roles of EVs as key mediators in this interaction. This review explores the pathological interplay between glioma and ischemic stroke, addressing clinical manifestations and pathophysiological processes across the stages of hypoxia, stroke onset, progression, and recovery, with a particular focus on the crucial role of EVs and their cargos in these interactions.

Advancing neurological disorders therapies: Organic nanoparticles as a key to blood-brain barrier penetration

The blood-brain barrier (BBB) plays a vital role in protecting the central nervous system (CNS) by preventing the entry of harmful pathogens from the bloodstream. However, this barrier also presents a significant obstacle when it comes to delivering drugs for the treatment of neurodegenerative diseases and brain cancer. Recent breakthroughs in nanotechnology have paved the way for the creation of a wide range of nanoparticles (NPs) that can serve as carriers for diagnosis and therapy. Regarding their promising properties, organic NPs have the potential to be used as effective carriers for drug delivery across the BBB based on recent advancements. These remarkable NPs have the ability to penetrate the BBB using various mechanisms. This review offers a comprehensive examination of the intricate structure and distinct properties of the BBB, emphasizing its crucial function in preserving brain balance and regulating the transport of ions and molecules. The disruption of the BBB in conditions such as stroke, Alzheimer's disease, and Parkinson's disease highlights the importance of developing creative approaches for delivering drugs. Through the encapsulation of therapeutic molecules and the precise targeting of transport processes in the brain vasculature, organic NP formulations present a hopeful strategy to improve drug transport across the BBB. We explore the changes in properties of the BBB in various pathological conditions and investigate the factors that affect the successful delivery of organic NPs into the brain. In addition, we explore the most promising delivery systems associated with NPs that have shown positive results in treating neurodegenerative and ischemic disorders. This review opens up new possibilities for nanotechnology-based therapies in cerebral diseases.

From Gut to Brain: The Impact of Short-Chain Fatty Acids on Brain Cancer

The primary source of short-chain fatty acids (SCFAs), now recognized as critical mediators of host health, particularly in the context of neurobiology and cancer development, is the gut microbiota's fermentation of dietary fibers. Recent research highlights the complex influence of SCFAs, such as acetate, propionate, and butyrate, on brain cancer progression. These SCFAs impact immune modulation and the tumor microenvironment, particularly in brain tumors like glioma. They play a critical role in regulating cellular processes, including apoptosis, cell differentiation, and inflammation. Moreover, studies have linked SCFAs to maintaining the integrity of the blood-brain barrier (BBB), suggesting a protective role in preventing tumor infiltration and enhancing anti-tumor immunity. As our understanding of the gut-brain axis deepens, it becomes increasingly important to investigate SCFAs' therapeutic potential in brain cancer management. Looking into how SCFAs affect brain tumor cells and the environment around them could lead to new ways to prevent and treat these diseases, which could lead to better outcomes for people who are dealing with these challenging cancers.

Exosomes as nature's nano carriers: Promising drug delivery tools and targeted therapy for glioma

Exosomes, minute vesicles originating from diverse cell types, exhibit considerable potential as carriers for drug delivery in glioma therapy. These naturally occurring nanocarriers facilitate the transfer of proteins, RNAs, and lipids between cells, offering advantages such as biocompatibility, efficient cellular absorption, and the capability to traverse the blood-brain barrier (BBB). In the realm of cancer, particularly gliomas, exosomes play pivotal roles in modulating tumor growth, regulating immunity, and combating drug resistance. Moreover, exosomes serve as valuable biomarkers for diagnosing diseases and assessing prognosis. This review aims to elucidate the therapeutic and diagnostic promise of exosomes in glioma treatment, highlighting the innovative advances in exosome engineering that enable precise drug loading and targeting. By circumventing challenges associated with current glioma treatments, exosome-mediated drug delivery strategies can enhance the efficacy of chemotherapy drugs like temozolomide and overcome drug resistance mechanisms. This review underscores the multifaceted roles of exosomes in glioma pathogenesis and therapy, underscoring their potential as natural nanocarriers for targeted therapy and heralding a new era of hope for glioma treatment.

A detailed evaluation of the advantages among extracellular vesicles from three cell origins for targeting delivery of celastrol and treatment of glioblastoma

As one of the most common brain tumors, glioblastoma (GBM) lacks efficient therapeutic treatment and remains lethal. Extracellular vesicles (EVs) have emerged as a promising platform for GBM therapies. Nevertheless, the properties of EVs are significantly influenced by their cell origins. This study aimed to evaluate the advantages of EVs derived from bone marrow mesenchymal stem cells (BMSCs), human glioblastoma cells (U-87 MG) and macrophage cells (RAW264.7) to develop a more effective strategy for the delivery of anti-GBM drug celastrol (Cel). Three kinds of EVs exhibited spherical- or oval-shapes with an average size ranging from 90 to 140 nm. Western blot analysis confirmed the presence of specific EV markers (ALIX, CD63 or TSG101). Notably, the yield of BMSCs-derived EVs (BMSC-EVs) significantly surpassed that of U-87 MG and RAW264.7 cells. Furthermore, BMSC-EVs demonstrated the highest entrapment efficiency for Cel (72 %) and enhanced internalization into the target cells U-87 MG. The increased cytotoxicity and cell apoptosis further confirmed that Cel-loaded BMSC-EVs (BMSC-EVs-Cel) were more potent for killing U-87 MG cells compared with free Cel. In vivo studies utilizing both orthotopic and subcutaneous GBM models revealed facilitated blood-brain barrier penetration and transportation of cargo into tumor tissue by BMSC-EVs. Importantly, BMSC-EVs-Cel could effectively inhibit GBM growth, induce tumor tissue apoptosis and suppress intratumoral microvessel density in comparison with free Cel and temozolomide, while successfully decrease systemic toxicity. Overall, this study elucidates the properties of EVs derived from distinct cell origins and highlights the great potential of BMSC-EVs for brain tumor treatment.

Nanotherapeutic strategy against glioblastoma using enzyme inhibitors

Glioblastoma is the most aggressive brain cancer and thus patients with glioblastoma have a severely low 5-year survival rate (<5 %). Glioblastoma damages neural centers, causing severe depression, anxiety, and cognitive disorders. Glioblastoma is highly resistant to most of available anti-tumor medications, due to heterogeneity of glioblastoma as well as the presence of stem-like cells. To overcome the challenges in the current medications against glioblastoma, novel medications that are effective in treating the aggressive and heterogenous glioblastoma should be developed. Enzyme inhibitor and nanomedicine have been getting attention because of effective anticancer efficacies of enzyme inhibitors and a role of nanomedicine as effective carrier of chemotherapeutic drugs by targeting specific tumor areas. Furthermore, a tumor-initiating neuroinflammatory microenvironment, which is crucial for glioblastoma progression, was linked with several carcinogenesis pathways. Therefore, in this review, first we summarize neuroinflammation and glioblastoma-related neuropathways. Second, we discuss the importance of enzyme inhibitors targeting specific proteins in relation with neuroinflammation and glioblastoma-related molecular mechanisms. Third, we summarize recent findings on the significance of nanotherapeutic anticancer drugs developed using natural or synthetic enzyme inhibitors against glioblastoma as well as currently available Food and Drug Administration (FDA)-approved drugs against glioblastoma.

Glioma immune microenvironment composition calculator (GIMiCC): a method of estimating the proportions of eighteen cell types from DNA methylation microarray data

A scalable platform for cell typing in the glioma microenvironment can improve tumor subtyping and immune landscape detection as successful immunotherapy strategies continue to be sought and evaluated. DNA methylation (DNAm) biomarkers for molecular classification of tumor subtypes have been developed for clinical use. However, tools that predict the cellular landscape of the tumor are not well-defined or readily available. We developed the Glioma Immune Microenvironment Composition Calculator (GIMiCC), an approach for deconvolution of cell types in gliomas using DNAm data. Using data from 17 isolated cell types, we describe the derivation of the deconvolution libraries in the biological context of selected genomic regions and validate deconvolution results using independent datasets. We utilize GIMiCC to illustrate that DNAm-based estimates of immune composition are clinically relevant and scalable for potential clinical implementation. In addition, we utilize GIMiCC to identify composition-independent DNAm alterations that are associated with high immune infiltration. Our future work aims to optimize GIMiCC and advance the clinical evaluation of glioma.

Blood-tumor barrier in focus - investigation of glioblastoma-induced effects on the blood-brain barrier

PURPOSE

Glioblastoma (GBM) is the most prevalent, malignant, primary brain tumor in adults, characterized by limited treatment options, frequent relapse, and short survival after diagnosis. Until now, none of the existing therapy and treatment approaches have proven to be an effective cure. The availability of predictive human blood-tumor barrier (BTB) test systems that can mimic in-vivo pathophysiology of GBM would be of great interest in preclinical research. Here, we present the establishment of a new BTB in-vitro test system combining GBM spheroids and BBB models derived from human induced pluripotent stem cells (hiPSCs).

METHODS

We co-cultured hiPSC-derived brain capillary endothelial-like cells (iBCECs) with GBM spheroids derived from U87-MG and U373-MG cell lines in a cell culture insert-based format. Spheroids were monitored over 168 hours (h) of culture, characterized for GBM-specific marker expression and treated with standard chemotherapeutics to distinguish inhibitory effects between 2D mono-culture and 3D spheroids. GBM-induced changes on iBCECs barrier integrity were verified via measurement of transendothelial electrical resistance (TEER), immunocytochemical staining of tight junction (TJ) proteins claudin-5 and occludin as well as the glucose transporter-1 (Glut-1). GBM-induced secretion of vascular endothelial growth factor (VEGF) was additionally quantified.

RESULTS

Our hypothesis was validated by reduced expression of TJ proteins, occludin and claudin-5 together with significant barrier breakdown in iBCECs after only 24 h of co-culture, demonstrated by reduction in TEER from 1313 ± 265 Ω*cm2 to 712 ± 299 Ω*cm2 (iBCECs + U87-MG) and 762 ± 316 Ω*cm2 (iBCECs + U373-MG). Furthermore, 3D spheroids show more resistance to standard GBM chemotherapeutics in-vitro compared to 2D cultures.

CONCLUSIONS

We demonstrate the establishment of a simplified, robust in-vitro BTB test system, with potential application in preclinical therapeutic screening and in studying GBM-induced pathological changes at the BBB.

Immunotherapeutic advances in glioma management: The rise of vaccine-based approaches

BACKGROUND

Gliomas, particularly glioblastoma multiforme (GBM), are highly aggressive brain tumors that present significant challenges in oncology due to their rapid progression and resistance to conventional therapies. Despite advancements in treatment, the prognosis for patients with GBM remains poor, necessitating the exploration of novel therapeutic approaches. One such emerging strategy is the development of glioma vaccines, which aim to stimulate the immune system to target and destroy tumor cells.

AIMS

This review aims to provide a comprehensive evaluation of the current landscape of glioma vaccine development, analyzing the types of vaccines under investigation, the outcomes of clinical trials, and the challenges and opportunities associated with their implementation. The goal is to highlight the potential of glioma vaccines in advancing more effective and personalized treatments for glioma patients.

MATERIALS AND METHODS

This narrative review systematically assessed the role of glioma vaccines by including full-text articles published between 2000 and 2024 in English. Databases such as PubMed/MEDLINE, EMBASE, the Cochrane Library, and Scopus were searched using key terms like "glioma," "brain tumor," "glioblastoma," "vaccine," and "immunotherapy." The review incorporated both pre-clinical and clinical studies, including descriptive studies, animal-model studies, cohort studies, and observational studies. Exclusion criteria were applied to omit abstracts, case reports, posters, and non-peer-reviewed studies, ensuring the inclusion of high-quality evidence.

RESULTS

Clinical trials investigating various glioma vaccines, including peptide-based, DNA/RNA-based, whole-cell, and dendritic-cell vaccines, have shown promising results. These vaccines demonstrated potential in extending survival rates and managing adverse events in glioma patients. However, significant challenges remain, such as therapeutic resistance due to tumor heterogeneity and immune evasion mechanisms. Moreover, the lack of standardized guidelines for evaluating vaccine responses and issues related to ethical considerations, regulatory hurdles, and vaccine acceptance among patients further complicate the implementation of glioma vaccines.

DISCUSSION

Addressing the challenges associated with glioma vaccines involves exploring combination therapies, targeted approaches, and personalized medicine. Combining vaccines with traditional therapies like radiotherapy or chemotherapy may enhance efficacy by boosting the immune system's ability to fight tumor cells. Personalized vaccines tailored to individual patient profiles present an opportunity for improved outcomes. Furthermore, global collaboration and equitable distribution are critical for ensuring access to glioma vaccines, especially in low- and middle-income countries with limited healthcare resources CONCLUSION: Glioma vaccines represent a promising avenue in the fight against gliomas, offering hope for improving patient outcomes in a disease that is notoriously difficult to treat. Despite the challenges, continued research and the development of innovative strategies, including combination therapies and personalized approaches, are essential for overcoming current barriers and transforming the treatment landscape for glioma patients.

The Use of Apparent Diffusion Coefficient Values for Differentiating Bevacizumab-Related Cytotoxicity from Tumor Recurrence and Radiation Necrosis in Glioblastoma

OBJECTIVES

Glioblastomas (GBM) are the most common primary invasive neoplasms of the brain. Distinguishing between lesion recurrence and different types of treatment related changes in patients with GBM remains challenging using conventional MRI imaging techniques. Therefore, accurate and precise differentiation between true progression or pseudoresponse is crucial in deciding on the appropriate course of treatment. This retrospective study investigated the potential of apparent diffusion coefficient (ADC) map values derived from diffusion-weighted imaging (DWI) as a noninvasive method to increase diagnostic accuracy in treatment response.

METHODS

A cohort of 21 glioblastoma patients (mean age: 59.2 ± 11.8, 12 Male, 9 Female) that underwent treatment with bevacizumab were selected. The ADC values were calculated from the DWI images obtained from a standardized brain protocol across 1.5-T and 3-T MRI scanners. Ratios were calculated for rADC values. Lesions were classified as bevacizumab-induced cytotoxicity based on characteristic imaging features (well-defined regions of restricted diffusion with persistent diffusion restriction over the course of weeks without tissue volume loss and absence of contrast enhancement). The rADC value was compared to these values in radiation necrosis and recurrent lesions, which were concluded in our prior study. The nonparametric Wilcoxon signed rank test with p < 0.05 was used for significance.

RESULTS

The mean ± SD age of the selected patients was 59.2 ± 11.8. ADC values and corresponding mean rADC values for bevacizumab-induced cytotoxicity were 248.1 ± 67.2 and 0.39 ± 0.10, respectively. These results were compared to the ADC values and corresponding mean rADC values of tumor progression and radiation necrosis. Significant differences between rADC values were observed in all three groups (p < 0.001). Bevacizumab-induced cytotoxicity had statistically significant lower ADC values compared to both tumor recurrence and radiation necrosis.

CONCLUSION

The study demonstrates the potential of ADC values as noninvasive imaging biomarkers for differentiating recurrent glioblastoma from radiation necrosis and bevacizumab-induced cytotoxicity.

Survival strategies: How tumor hypoxia microenvironment orchestrates angiogenesis

During tumor development, the tumor itself must continuously generate new blood vessels to meet their growth needs while also allowing for tumor invasion and metastasis. One of the most common features of tumors is hypoxia, which drives the process of tumor angiogenesis by regulating the tumor microenvironment, thus adversely affecting the prognosis of patients. In addition, to overcome unsuitable environments for growth, such as hypoxia, nutrient deficiency, hyperacidity, and immunosuppression, the tumor microenvironment (TME) coordinates angiogenesis in several ways to restore the supply of oxygen and nutrients and to remove metabolic wastes. A growing body of research suggests that tumor angiogenesis and hypoxia interact through a complex interplay of crosstalk, which is inextricably linked to the TME. Here, we review the TME's positive contribution to angiogenesis from an angiogenesis-centric perspective while considering the objective impact of hypoxic phenotypes and the status and limitations of current angiogenic therapies.

Blood-Brain Barrier-Targeting Nanoparticles: Biomaterial Properties and Biomedical Applications in Translational Neuroscience

Overcoming the blood-brain barrier (BBB) remains a significant hurdle in effective drug delivery to the brain. While the BBB serves as a crucial protective barrier, it poses challenges in delivering therapeutic agents to their intended targets within the brain parenchyma. To enhance drug delivery for the treatment of neurological diseases, several delivery technologies to circumvent the BBB have been developed in the last few years. Among them, nanoparticles (NPs) are one of the most versatile and promising tools. Here, we summarize the characteristics of NPs that facilitate BBB penetration, including their size, shape, chemical composition, surface charge, and importantly, their conjugation with various biological or synthetic molecules such as glucose, transferrin, insulin, polyethylene glycol, peptides, and aptamers. Additionally, we discuss the coating of NPs with surfactants. A comprehensive overview of the common in vitro and in vivo models of the BBB for NP penetration studies is also provided. The discussion extends to discussing BBB impairment under pathological conditions and leveraging BBB alterations under pathological conditions to enhance drug delivery. Emphasizing the need for future studies to uncover the inherent therapeutic properties of NPs, the review advocates for their role beyond delivery systems and calls for efforts translating NPs to the clinic as therapeutics. Overall, NPs stand out as a highly promising therapeutic strategy for precise BBB targeting and drug delivery in neurological disorders.

Immunological processes of enhancers and suppressors of long non-coding RNAs associated with brain tumors and inflammation

Immunological processes, such as inflammation, can both cause tumor suppression and cancer progression. Moreover, deregulated levels of long non-coding RNA (lncRNA) expression in the brain may cause inflammation and lead to the growth of tumors. Like other biological processes, the immune system's role in cancer is complicated, varies, and can help or hurt the cancer's maintenance. According to research, inflammation and brain cancer are correlated via several signaling pathways. A variety of lncRNAs have recently been revealed to influence cancer by modulating inflammatory pathways. As a result, lncRNAs have the potential to influence carcinogenesis, tumor formation, or tumor suppression via an increase or decrease in inflammation functions. Although the study and targeting of lncRNAs have made great progress in the treatment of cancer, there are definitely limitations and challenges. Using new technologies like nanocarriers and cell-penetrating peptides (CPPs) to target treatments without hurting healthy body tissues has shown to be very effective. In this review article, we have collected significantly related lncRNAs and their inhibitory or stimulating roles in inflammation and brain cancer for the first time. However, there are limitations, such as side effects and damage to normal tissues. With the advancement of new targeting technologies, these lncRNAs may be candidates for the specific targeting therapy of brain cancers by limiting inflammation or stimulating the immune system against them in the future.

Unexplained Causes of Glioma-Associated Epilepsies: A Review of Theories and an Area for Research

Approximately 30% of glioma patients are able to survive beyond one year postdiagnosis. And this short time is often overshadowed by glioma-associated epilepsy. This condition severely impairs the patient's quality of life and causes great suffering. The genetic, molecular and cellular mechanisms underlying tumour development and epileptogenesis remain incompletely understood, leading to numerous unanswered questions. The various types of gliomas, namely glioblastoma, astrocytoma and oligodendroglioma, demonstrate distinct seizure susceptibility and disease progression patterns. Patterns have been identified in the presence of IDH mutations and epilepsy, with tumour location in cortical regions, particularly the frontal lobe, showing a more frequent association with seizures. Altered expression of TP53, MGMT and VIM is frequently detected in tumour cells from individuals with epilepsy associated with glioma. However, understanding the pathogenesis of these modifications poses a challenge. Moreover, hypoxic effects induced by glioma and associated with the HIF-1a factor may have a significant impact on epileptogenesis, potentially resulting in epileptiform activity within neuronal networks. We additionally hypothesise about how the tumour may affect the functioning of neuronal ion channels and contribute to disruptions in the blood-brain barrier resulting in spontaneous depolarisations.

Differential metabolic alterations in IDH1 mutant vs. wildtype glioma cells promote epileptogenesis through distinctive mechanisms

Glioma-related epilepsy (GRE) is a hallmark clinical presentation of gliomas with significant impacts on patient quality of life. The current standard of care for seizure management is comprised of anti-seizure medications (ASMs) and surgical resection. Seizures in glioma patients are often drug-resistant and can often recur after surgery despite total tumor resection. Therefore, current research is focused on the pro-epileptic pathological changes occurring in tumor cells and the peritumoral environment. One important contribution to seizures in GRE patients is metabolic reprogramming in tumor and surrounding cells. This is most evident by the significantly heightened seizure rate in patients with isocitrate dehydrogenase mutated (IDHmut) tumors compared to patients with IDH wildtype (IDHwt) gliomas. To gain further insight into glioma metabolism in epileptogenesis, this review compares the metabolic changes inherent to IDHmut vs. IDHwt tumors and describes the pro-epileptic effects these changes have on both the tumor cells and the peritumoral environment. Understanding alterations in glioma metabolism can help to uncover novel therapeutic interventions for seizure management in GRE patients.

Migration-Associated Transportome and Therapeutic Potential in Glioblastoma Multiforme (GBM)

GBM is a highly aggressive and very common malignant form of primary brain tumors in adults [...].

Cell-free DNA-based liquid biopsies in neurology

This article reviews recent developments in the application of cell-free DNA-based liquid biopsies to neurological diseases. Over the past few decades, an explosion of interest in the use of accessible biofluids to identify and track molecular disease has revolutionized the fields of oncology, prenatal medicine and others. More recently, technological advances in signal detection have allowed for informative analysis of biofluids that are typically sparse in cells and other circulating components, such as CSF. In parallel, advancements in epigenetic profiling have allowed for novel applications of liquid biopsies to diseases without characteristic mutational profiles, including many degenerative, autoimmune, inflammatory, ischaemic and infectious disorders. These events have paved the way for a wide array of neurological conditions to benefit from enhanced diagnostic, prognostic, and treatment abilities through the use of liquid biomarkers: a 'liquid biopsy' approach. This review includes an overview of types of liquid biopsy targets with a focus on circulating cell-free DNA, methods used to identify and probe potential liquid biomarkers, and recent applications of such biomarkers to a variety of complex neurological conditions including CNS tumours, stroke, traumatic brain injury, Alzheimer's disease, epilepsy, multiple sclerosis and neuroinfectious disease. Finally, the challenges of translating liquid biopsies to use in clinical neurology settings-and the opportunities for improvement in disease management that such translation may provide-are discussed.

Lipid-Based Nanocarriers in the Treatment of Glioblastoma Multiforme (GBM): Challenges and Opportunities

Glioblastoma multiforme (also known as glioblastoma; GBM) is one of the most malignant types of brain tumors that occurs in the CNS. Treatment strategies for glioblastoma are majorly comprised of surgical resection, radiotherapy, and chemotherapy along with combination therapy. Treatment of GBM is itself a tedious task but the involved barriers in GBM are one of the main impediments to move one step closer to the treatment of GBM. Basically, two of the barriers are of utmost importance in this regard, namely blood brain barrier (BBB) and blood brain tumor barrier (BBTB). This review will address different challenges and barriers in the treatment of GBM along with their etiology. The role and recent progress of lipid-based nanocarriers like liposomes, solid lipid nanocarriers (SLNs), nanostructured lipid carriers (NLCs), lipoplexes, and lipid hybrid carriers in the effective management of GBM will be discussed in detail.

A three-component multi-b-value diffusion-weighted imaging might be a useful biomarker for detecting microstructural features in gliomas with differences in malignancy and IDH-1 mutation status

OBJECTIVES

The purpose of the study was to explore the performance of a three-component diffusion model in evaluating the degree of malignancy and isocitrate dehydrogenase 1 (IDH-1) gene type of gliomas.

METHODS

Overall, 60 patients with gliomas were enrolled. The intermediate and perfusion-related diffusion coefficients (D_int and D_p) and fractions of strictly limited, intermediate, and perfusion-related diffusion (F_very-slow, F_int, and F_p) were obtained with a three-component diffusion model. Parameters were also obtained from a diffusion kurtosis model and mono- and biexponential models. All parameters were compared between different tumor grades and IDH-1 gene types. Diagnostic performance and logistic regression analyses were performed.

RESULTS

High-grade gliomas (HGGs) had significantly higher F_int, F_very-slow, and D_p values but significantly lower F_p and D_int values than low-grade gliomas (LGGs), and F_int and F_p differed significantly among grade II, III, and IV gliomas (p < 0.05 for all). F_int achieved the highest AUC of 0.872 in differentiating between LGGs and HGGs. Logistic regression analysis revealed that in each model, F_int, diffusion coefficient (D), apparent diffusion coefficient (ADC), mean diffusivity (MD), and mean kurtosis (MK) were associated with glioma grading. After multiple regression analysis, F_int remained the only differentiator. Additionally, F_int and F_p showed significant differences between IDH-1 mutated and IDH-1 wild-type gliomas (p = 0.007 and 0.01, respectively).

CONCLUSIONS

The three-component DWI model served as a useful biomarker for detecting microstructural features in gliomas with different grades and IDH-1 mutation statuses.

KEY POINTS

• The three-component model enables the estimation of an intermediate diffusion component. • The three-component model performed better than the other models in glioma grading and genotyping. • F_int was useful in evaluating the grade and genotype of gliomas.

Mutated Isocitrate Dehydrogenase (mIDH) as Target for PET Imaging in Gliomas

Gliomas are the most common primary brain tumors in adults. A diffuse infiltrative growth pattern and high resistance to therapy make them largely incurable, but there are significant differences in the prognosis of patients with different subtypes of glioma. Mutations in isocitrate dehydrogenase (IDH) have been recognized as an important biomarker for glioma classification and a potential therapeutic target. However, current clinical methods for detecting mutated IDH (mIDH) require invasive tissue sampling and cannot be used for follow-up examinations or longitudinal studies. PET imaging could be a promising approach for non-invasive assessment of the IDH status in gliomas, owing to the availability of various mIDH-selective inhibitors as potential leads for the development of PET tracers. In the present review, we summarize the rationale for the development of mIDH-selective PET probes, describe their potential applications beyond the assessment of the IDH status and highlight potential challenges that may complicate tracer development. In addition, we compile the major chemical classes of mIDH-selective inhibitors that have been described to date and briefly consider possible strategies for radiolabeling of the most promising candidates. Where available, we also summarize previous studies with radiolabeled analogs of mIDH inhibitors and assess their suitability for PET imaging in gliomas.

Ion Channels in Gliomas-From Molecular Basis to Treatment

Ion channels provide the basis for the nervous system's intrinsic electrical activity. Neuronal excitability is a characteristic property of neurons and is critical for all functions of the nervous system. Glia cells fulfill essential supportive roles, but unlike neurons, they also retain the ability to divide. This can lead to uncontrolled growth and the formation of gliomas. Ion channels are involved in the unique biology of gliomas pertaining to peritumoral pathology and seizures, diffuse invasion, and treatment resistance. The emerging picture shows ion channels in the brain at the crossroads of neurophysiology and fundamental pathophysiological processes of specific cancer behaviors as reflected by uncontrolled proliferation, infiltration, resistance to apoptosis, metabolism, and angiogenesis. Ion channels are highly druggable, making them an enticing therapeutic target. Targeting ion channels in difficult-to-treat brain tumors such as gliomas requires an understanding of their extremely heterogenous tumor microenvironment and highly diverse molecular profiles, both representing major causes of recurrence and treatment resistance. In this review, we survey the current knowledge on ion channels with oncogenic behavior within the heterogeneous group of gliomas, review ion channel gene expression as genomic biomarkers for glioma prognosis and provide an update on therapeutic perspectives for repurposed and novel ion channel inhibitors and electrotherapy.

Polymeric and small molecule-conjugates of temozolomide as improved therapeutic agents for glioblastoma multiforme

Temozolomide (TMZ), an imidazotetrazine, is a second-generation DNA alkylating agent used as a first-line treatment of glioblastoma multiforme (GBM). It was approved by FDA in 2005 and declared a blockbuster drug in 2008. Although TMZ has shown 100% oral bioavailability and crosses the blood-brain barrier effectively, however it suffers from limitations such as a short half-life (∼1.8 h), rapid metabolism, and lesser accumulation in the brain (∼10-20%). Additionally, development of chemoresistance has been associated with its use. Since it is a potential chemotherapeutic agent with an unmet medical need, advanced delivery strategies have been explored to overcome the associated limitations of TMZ. Nanocarriers including liposomes, solid lipid nanoparticles (SLNs), nanostructure lipid carriers (NLCs), and polymeric nanoparticles have demonstrated their ability to improve its circulation time, stability, tissue-specific accumulation, sustained release, and cellular uptake. Because of the appreciable water solubility of TMZ (∼5 mg/mL), the physical loading of TMZ in these nanocarriers is always challenging. Alternatively, the conjugation approach, wherein TMZ has been conjugated to polymers or small molecules, has been explored with improved outcomes in vitro and in vivo. This review emphasized the practical evidence of the conjugation strategy to improve the therapeutic potential of TMZ in the treatment of glioblastoma multiforme.

The epigenetic-metabolic interplay in gliomagenesis

Although tumourigenesis occurs due to genetic mutations, the role of epigenetic dysregulations in cancer is also well established. Epigenetic dysregulations in cancer may occur as a result of mutations in genes encoding histone/DNA-modifying enzymes and chromatin remodellers or mutations in histone protein itself. It is also true that misregulated gene expression without genetic mutations in these factors could also support tumour initiation and progression. Interestingly, metabolic rewiring has emerged as a hallmark of cancer due to gene mutations in specific metabolic enzymes or dietary/environmental factors. Recent studies report an intricate cross-talk between epigenetic and metabolic reprogramming in cancer. This review discusses the role of epigenetic and metabolic dysregulations and their cross-talk in tumourigenesis with a special focus on gliomagenesis. We also discuss the role of recently developed human embryonic stem cells/induced pluripotent stem cells-derived organoid models of gliomas and how these models are proving instrumental in uncovering human-specific cellular and molecular complexities of gliomagenesis.

Innate Lymphoid Cells in the Central Nervous System

Immune cells are present within the central nervous system and play important roles in neurological inflammation and disease. As relatively new described immune cell population, Innate Lymphoid Cells are now increasingly recognized within the central nervous system and associated diseases. Innate Lymphoid Cells are generally regarded as tissue resident and early responders, while conversely within the central nervous system at steady-state their presence is limited. This review describes the current understandings on Innate Lymphoid Cells in the central nervous system at steady-state and its borders plus their involvement in major neurological diseases like ischemic stroke, Alzheimer's disease and Multiple Sclerosis.

Recent Development in NKT-Based Immunotherapy of Glioblastoma: From Bench to Bedside

Glioblastoma multiforme (GBM) is an aggressive and dismal disease with a median overall survival of around 15 months and a 5-year survival rate of 7.2%. Owing to genetic mutations, drug resistance, disruption to the blood–brain barrier (BBB)/blood–brain tumor barrier (BBTB), and the complexity of the immunosuppressive environment, the therapeutic approaches to GBM represent still major challenges. Conventional therapies, including surgery, radiotherapy, and standard chemotherapy with temozolomide, have not resulted in satisfactory improvements in the overall survival of GBM patients. Among cancer immunotherapeutic approaches, we propose that adjuvant NKT immunotherapy with invariant NKT (iNKT) and cytokine-induced killer (CIK) cells may improve the clinical scenario of this devastating disease. Considering this, herein, we discuss the current strategies of NKT therapy for GBM based primarily on in vitro/in vivo experiments, clinical trials, and the combinatorial approaches with future therapeutic potential.

In vitro antitumor activity of dialkylamine-1,4-naphthoquinones toward human glioblastoma multiforme cells

In this study, we evaluated the in vitro antitumor activity of dialkylamino-1,4-naphthoquinones (1a–n) toward human glioblastoma multiforme cells (GBM02).

Simulation of magnetic nanoparticles crossing through a simplified blood-brain barrier model for Glioblastoma multiforme treatment

BACKGROUND AND OBJECTIVES

Glioblastoma multiforme is considered as one of the most aggressive types of cancer, while various treatment techniques have been proposed. Magnetic nanoparticles (MNPs) loaded with drug and magnetically controlled and targeted to tissues affected by disease, is considered as a possible treatment. However, MNPs are difficult to penetrate the central nervous system and approach the unhealthy tissue, because of the blood-brain barrier (BBB). This study investigates numerically the delivery of magnetic nanoparticles through the barrier driven by normal pressure drop and external gradient magnetic fields, employing a simplified geometrical model, computational fluid dynamics and discrete element method. The goal of the study is to provide information regarding the permeability of the BBB under various conditions like the imposed forces and the shape of the domain, as a preliminary predictive tool.

METHODS

To achieve that, the three-dimensional Navier-Stokes equations are solved in the margin of a blood vessel along with a discrete model for the MNPs with various acting forces. The numerical results are compared with experimental measurements showing that the model can predict acceptably the flow behavior.

RESULTS

The effect of nanoparticles' size, external magnetic field and blood flow in the vessel, on the brain-barrier's permeability are investigated. Three different cases of available area among the endothelial cells per the MNPs' size ratio are also examined, showing that the MNPs' size and available area is not the dominant parameter affecting the permeability of the BBB. The results indicate that the applied magnetic field enhances the drug delivery into the central nervous system (CNS). When larger MNPs (∼100 nm) are exposed to an external magnetic field, the permeability can be improved up to 30%, while it is shown that smaller MNPs (∼10 nm) cannot be driven by the applied magnetic field and in this case the permeability remains relatively unchanged. Finally, the blood flow increase leads to a permeability improvement up to 15%.

CONCLUSIONS

The applied magnetic field improves up to 45% the permeability of the BBB for MNPs of 100 nm. The geometric characteristics of the endothelial cells, the nanoparticles' size and the blood flow are not so decisive parameters for the drug delivery into the CNS, compared to the external magnetic force.

Biobanked Glioblastoma Patient-Derived Organoids as a Precision Medicine Model to Study Inhibition of Invasion

Glioblastoma (GBM) is highly resistant to treatment and invasion into the surrounding brain is a cancer hallmark that leads to recurrence despite surgical resection. With the emergence of precision medicine, patient-derived 3D systems are considered potentially robust GBM preclinical models. In this study, we screened a library of 22 anti-invasive compounds (i.e., NF-kB, GSK-3-B, COX-2, and tubulin inhibitors) using glioblastoma U-251 MG cell spheroids. We evaluated toxicity and invasion inhibition using a 3D Matrigel invasion assay. We next selected three compounds that inhibited invasion and screened them in patient-derived glioblastoma organoids (GBOs). We developed a platform using available macros for FIJI/ImageJ to quantify invasion from the outer margin of organoids. Our data demonstrated that a high-throughput invasion screening can be done using both an established cell line and patient-derived 3D model systems. Tubulin inhibitor compounds had the best efficacy with U-251 MG cells, however, in ex vivo patient organoids the results were highly variable. Our results indicate that the efficacy of compounds is highly related to patient intra and inter-tumor heterogeneity. These results indicate that such models can be used to evaluate personal oncology therapeutic strategies.