Glioblastoma multiforme: Pathogenesis and treatment

Advanced 3D Models of Human Brain Tissue Using Neural Cell Lines: State-of-the-Art and Future Prospects

Human-relevant three-dimensional (3D) models of cerebral tissue can be invaluable tools to boost our understanding of the cellular mechanisms underlying brain pathophysiology. Nowadays, the accessibility, isolation and harvesting of human neural cells represents a bottleneck for obtaining reproducible and accurate models and gaining insights in the fields of oncology, neurodegenerative diseases and toxicology. In this scenario, given their low cost, ease of culture and reproducibility, neural cell lines constitute a key tool for developing usable and reliable models of the human brain. Here, we review the most recent advances in 3D constructs laden with neural cell lines, highlighting their advantages and limitations and their possible future applications.

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.

Mechanisms of Resistance and Current Treatment Options for Glioblastoma Multiforme (GBM)

Glioblastoma multiforme (GBM) is a highly aggressive form of brain cancer that is difficult to treat due to its resistance to both radiation and chemotherapy. This resistance is largely due to the unique biology of GBM cells, which can evade the effects of conventional treatments through mechanisms such as increased resistance to cell death and rapid regeneration of cancerous cells. Additionally, the blood–brain barrier makes it difficult for chemotherapy drugs to reach GBM cells, leading to reduced effectiveness. Despite these challenges, there are several treatment options available for GBM. The standard of care for newly diagnosed GBM patients involves surgical resection followed by concurrent chemoradiotherapy and adjuvant chemotherapy. Emerging treatments include immunotherapy, such as checkpoint inhibitors, and targeted therapies, such as bevacizumab, that attempt to attack specific vulnerabilities in GBM cells. Another promising approach is the use of tumor-treating fields, a type of electric field therapy that has been shown to slow the growth of GBM cells. Clinical trials are ongoing to evaluate the safety and efficacy of these and other innovative treatments for GBM, intending to improve with outcomes for patients.

Synthesis and evaluation of 99mTc-labeled 1-(2-Pyridyl)piperazine derivatives as radioligands for 5HT7 receptors

Glioblastoma multiform (GBM) is one of the most aggressive tumors of the central nervous system in humans. GBM overexpresses serotonin-7 receptors (5-HT₇Rs); hence, this study aims to develop 5-HT₇R targeted radiotracers. Aryl piperazine derivatives can act as ligands for 5-HT₇R. Therefore, compounds 6 and 7 as 1-(3-nitropyridin-2-yl)piperazine derivatives were synthesized and radiolabeled with ^99mTcN²⁺ core. Radiolabeled 6 and 7 (^99mTcN-[6] and ^99mTcN-[7]) were prepared with high radiochemical purity (RCP > 96%). They displayed high affinity toward U-87 MG cell line 5-HT₇R. The calculated K_i for ^99mTcN-[7] was lower than that of ^99mTcN-[6] (14.85 ± 0.32 vs 22.57 ± 0.73 nM) which indicates the higher affinity of ^99mTcN-[7] toward 5-HT₇R. A molecular docking study also confirmed the binding of these radiotracers to 5-HT₇R. The biodistribution study in normal mice revealed that ^99mTcN-[7] has the highest brain accumulation at 30 min post-injection (0.54 ± 0.12 %ID/g) while the uptake of ^99mTcN-[6] is much lower (0.14 ± 0.02 %ID/g). The biodistribution study in the xenograft model confirms that the radiotracers recognize the tumor site. ^99mTcN-[6], and ^99mTcN-[7] showed the highest tumor uptake at 1-hour post-injection (5.44 ± 0.58 vs 4.94 ± 1.65 %ID/g) and tumor-to-muscle ratios were (4.61 vs. 5.61). The injection of pimozide blocks the receptors and significantly reduces the tumor-to-muscle ratios at 1-hour post-injection to 0.81 and 0.31, respectively. In correlation with in vitro study, ^99mTcN-[6] and ^99mTcN-[7] visualize the tumor site in U-87 MG glioma xenografted nude mice and display the tumor-to-muscle ratios of 7.05 and 6.03.

Clinical, pharmacological, and formulation evaluation of disulfiram in the treatment of glioblastoma - a systematic literature review

INTRODUCTION

Glioblastoma (GB) is one of the most challenging central nervous system (CNS) tumors in treatment options and response, urging the development of novel management strategies. The anti-alcoholism drug, disulfiram (DS), has a potential anticancer activity, and its complex mechanism of action is assumed to be well exploited against the heterogeneous GB.

AREA COVERED

Through a systematic literature review about repositioning DS to GB treatment, an evaluation of the clinical, pharmacological, and formulation strategies is provided to specify the challenges of drug delivery and thus to advance its clinical translation. From six databases, 35 articles were selected, including case report (1); clinical trials (3); original articles mainly representing in vitro and preclinical pharmacological data, and 10 dealing with technological approaches.

EXPERT OPINION

The repositioning of DS in GB treatment is facing drug and tumor-associated limitations due to the oral drug's low bioavailability, unwanted metabolism, and inefficient delivery to brain-tumor tissue. Development strategies using molecular encapsulation of DS and the parenteral dosage forms improve the anticancer pharmacology of the drug. The development of optimized drug delivery systems (DDS) shows promise for the clinical translation of DS into GB adjuvant therapy.

The short isoform of MS4A7 is a novel player in glioblastoma microenvironment, M2 macrophage polarization, and tumor progression

BACKGROUND

The unique intracranial tumor microenvironment (TME) contributes to the immunotherapy failure for glioblastoma (GBM), thus new functional protein targets are urgently needed. Alternative splicing is a widespread regulatory mechanism by which individual gene can express variant proteins with distinct functions. Moreover, proteins located in the cell plasma membrane facilitate targeted therapies. This study sought to obtain functional membrane protein isoforms from GBM TME.

METHODS

With combined single-cell RNA-seq and bulk RNA-seq analyses, novel candidate membrane proteins generated by prognostic splicing events were screened within GBM TME. The short isoform of MS4A7 (MS4A7-s) was selected for evaluation by RT-PCR and western blotting in clinical specimens. Its clinical relevance was evaluated in a GBM patient cohort. The function of MS4A7-s was identified by in vitro and in vivo experiments. MS4A7-s overexpression introduced transcriptome changes were analyzed to explore the potential molecular mechanism.

RESULTS

The main expression product, isoform MS4A7-s, generated by exon skipping, is an M2-specific plasma membrane protein playing a pro-oncogenic role in GBM TME. Higher expression of MS4A7-s correlates with poor prognosis in a GBM cohort. In vitro cell co-culture experiments, intracranial co-injection tumorigenesis assay, and RNA-seq suggest MS4A7-s promotes activation of glioma-associated macrophages' (GAMs) PI3K/AKT/GSK3β pathway, leading to M2 polarization, and drives malignant progression of GBM.

CONCLUSIONS

MS4A7-s, a novel splicing isoform of MS4A7 located on the surface of GAMs in GBM TME, is a predictor of patient outcome, which contributes to M2 polarization and the malignant phenotype of GBM. Targeting MS4A7-s may constitute a promising treatment for GBM.

Highlighted Advances in Therapies for Difficult-To-Treat Brain Tumours Such as Glioblastoma

Glioblastoma multiforme (GBM) remains a challenging disease, as it is the most common and deadly brain tumour in adults and has no curative solution and an overall short survival time. This incurability and short survival time means that, despite its rarity (average incidence of 3.2 per 100,000 persons), there has been an increased effort to try to treat this disease. Standard of care in newly diagnosed glioblastoma is maximal tumour resection followed by initial concomitant radiotherapy and temozolomide (TMZ) and then further chemotherapy with TMZ. Imaging techniques are key not only to diagnose the extent of the affected tissue but also for surgery planning and even for intraoperative use. Eligible patients may combine TMZ with tumour treating fields (TTF) therapy, which delivers low-intensity and intermediate-frequency electric fields to arrest tumour growth. Nonetheless, the blood–brain barrier (BBB) and systemic side effects are obstacles to successful chemotherapy in GBM; thus, more targeted, custom therapies such as immunotherapy and nanotechnological drug delivery systems have been undergoing research with varying degrees of success. This review proposes an overview of the pathophysiology, possible treatments, and the most (not all) representative examples of the latest advancements.

Nasal administration of a temozolomide-loaded thermoresponsive nanoemulsion reduces tumor growth in a preclinical glioblastoma model

Glioblastoma (GB) is the worst and most common primary brain tumor. Temozolomide (TMZ), an alkylating agent, is widely used for treating primary and recurrent high-grade gliomas. However, at least 50% of TMZ treated patients do not respond to TMZ and the development of chemoresistance is a major problem. Here, we designed a lipid nanoemulsion containing a thermoresponsive polymer (poloxamer 407) aiming to improve TMZ release into the brain via nasal delivery. Increasing amounts of poloxamer 407 were added to preformed nanoemulsions (250 nm-range) obtained by spontaneous emulsification. The influence of the polymer concentration (from 2.5% to 12.5%) and temperature on viscosity was clearly evidenced. Such effect was also noticed on the mucoadhesiveness of formulations, as well as TMZ release rate and retention/permeation through nasal porcine mucosa using Franz-type diffusion cells. From these results, a formulation containing 10% of poloxamer (NTMZ-P10) was selected for further experiments by nasal route. A significantly higher TMZ amount was observed in the brain of rats from NTMZ-P10 in comparison with controls. Finally, our results show that formulation reduced significantly tumor growth by three-fold: 103.88 ± 43.67 mm³ (for NTMZ-P10) and 303.28 ± 95.27 mm³ (control). Overall, these results suggest the potential of the thermoresponsive formulation, administered by the non-invasive nasal route, as a future effective glioblastoma treatment.

Update for astrocytomas: medical and surgical management considerations

Astrocytomas include a wide range of tumors with unique mutations and varying grades of malignancy. These tumors all originate from the astrocyte, a star-shaped glial cell that plays a major role in supporting functions of the central nervous system (CNS), including blood-brain barrier (BBB) development and maintenance, water and ion regulation, influencing neuronal synaptogenesis, and stimulating the immunological response. In terms of epidemiology, glioblastoma (GB), the most common and malignant astrocytoma, generally occur with higher rates in Australia, Western Europe, and Canada, with the lowest rates in Southeast Asia. Additionally, significantly higher rates of GB are observed in males and non-Hispanic whites. It has been suggested that higher levels of testosterone observed in biological males may account for the increased rates of GB. Hereditary syndromes such as Cowden, Lynch, Turcot, Li-Fraumeni, and neurofibromatosis type 1 have been linked to increased rates of astrocytoma development. While there are a number of specific gene mutations that may influence malignancy or be targeted in astrocytoma treatment, O6-methylguanine-DNA methyltransferase (MGMT) gene function is an important predictor of astrocytoma response to chemotherapeutic agent temozolomide (TMZ). TMZ for primary and bevacizumab in the setting of recurrent tumor formation are two of the main chemotherapeutic agents currently approved in the treatment of astrocytomas. While stereotactic radiosurgery (SRS) has debatable implications for increased survival in comparison to whole-brain radiotherapy (WBRT), SRS demonstrates increased precision with reduced radiation toxicity. When considering surgical resection of astrocytoma, the extent of resection (EoR) is taken into consideration. Subtotal resection (STR) spares the margins of the T1 enhanced magnetic resonance imaging (MRI) region, gross total resection (GTR) includes the margins, and supramaximal resection (SMR) extends beyond the margin of the T1 and into the T2 region. Surgical resection, radiation, and chemotherapy are integral components of astrocytoma treatment.

Identification of Dysregulated microRNAs in Glioblastoma Stem-like Cells

Glioblastoma multiforme (GBM) is the most common malignant primary brain tumor in adults. Despite multimodal therapy, median survival is poor at 12-15 months. At the molecular level, radio-/chemoresistance and resulting tumor progression are attributed to a small fraction of tumor cells, termed glioblastoma stem-like cells (GSCs). These CD133-expressing, self-renewing cells display the properties of multi-lineage differentiation, resulting in the heterogenous composition of GBM. MicroRNAs (miRNAs) as regulators of gene expression at the post-transcriptional level can alter many pathways pivotal to cancer stem cell fate. This study explored changes in the miRNA expression profiles in patient-derived GSCs altered on differentiation into glial fiber acid protein (GFAP)-expressing, astrocytic tumor cells using a polymerase chain reaction (PCR) array. Initially, 22 miRNAs showed higher expression in GSCs and 9 miRNAs in differentiated cells. The two most downregulated miRNAs in differentiated GSCs were miR-17-5p and miR-425-5p, whilst the most upregulated miRNAs were miR-223-3p and let-7-5p. Among those, miR-425-5p showed the highest consistency in an upregulation in all three GSCs. By transfection of a 425-5p miRNA mimic, we demonstrated downregulation of the GFAP protein in differentiated patient-derived GBM cells, providing potential evidence for direct regulation of miRNAs in the GSC/GBM cell transition.

Influence of measurement mode on the results of glioblastoma multiforme analysis with the FTIR microspectroscopy

Fourier Transform Infrared (FTIR) microspectroscopy is well known for its effectiveness in spectral and biochemical analyses of various materials. It enables to determine the sample biochemical composition by assigning detected frequencies, characteristic for functional groups of main biological macromolecules. In analysis of tissue sections one of two measurement modes, namely transmission and transflection, is usually applied. The first one has relatively straightforward geometry, hence it is considered to be more precise and accurate. However, IR-transparent media are very fragile and expensive. Transflection does not require expensive substrates, but is more prone to disruptive influence of Mie scattering as well as electric field standing wave effect. The excessive comparison of spectra' characteristics, obtained via both measurement modes, was performed in this paper. By the means of Mann-Whitney non-parametrical U test and PCA, the comparison of results obtained with both modes and assessment of usefulness of IR spectra obtained with transmission and transflection modes to differentiate between healthy and GBM-affected tissue, were performed. The main objective of the presented research is to compare the results of FTIR analysis of unfixed biological samples performed with transflection and transmission mode. In frame of the study we demonstrated the discrepancies between results of biochemical analysis performed based on data obtained with transmission and transflection. Such observation suggests that caution should be taken in drawing conclusions from the results obtained with transflection geometry, as its more prone to disruptive effects. Despite that, IR spectra developed with both modes allowed to distinguish GBM area from healthy tissue, which proves their diagnostic potential. Especially, application of the ME-EMSC correction of spectra before PCA enhances the performance of both methods to distinguish the analysed tissue areas.

Small-molecule toosendanin reverses macrophage-mediated immunosuppression to overcome glioblastoma resistance to immunotherapy

T cell-based immunotherapy holds promise for treating solid tumors, but its therapeutic efficacy is limited by intratumoral immune suppression. This immune suppressive tumor microenvironment is largely driven by tumor-associated myeloid cells, including macrophages. Here, we report that toosendanin (TSN), a small-molecule compound, reprograms macrophages to enforce antitumor immunity in glioblastoma (GBM) in mouse models. Our functional screen of genetically probed macrophages with a chemical library identifies that TSN reverses macrophage-mediated tumor immunosuppression, leading to enhanced T cell infiltration, activation, and reduced exhaustion. Chemoproteomic and structural analyses revealed that TSN interacts with Hck and Lyn to abrogate suppressive macrophage immunity. In addition, a combination of immune checkpoint blockade and TSN therapy induced regression of syngeneic GBM tumors in mice. Furthermore, TSN treatment sensitized GBM to Egfrviii chimeric antigen receptor (CAR) T cell therapy. These findings suggest that TSN may serve as a therapeutic compound that blocks tumor immunosuppression and circumvents tumor resistance to T cell-based immunotherapy in GBM and other solid tumors that warrants further investigation.

Raman Spectroscopy Characterization of Multi-Functionalized Liposomes as Drug-Delivery Systems for Neurological Disorders

The characterization of nanoparticle-based drug-delivery systems represents a crucial step in achieving a comprehensive overview of their physical, chemical, and biological features and evaluating their efficacy and safety in biological systems. We propose Raman Spectroscopy (RS) for the characterization of liposomes (LPs) to be tested for the control of neuroinflammation and microglial dysfunctions in Glioblastoma multiforme and Alzheimer's disease. Drug-loaded LPs were functionalized to cross the blood-brain barrier and to guarantee localized and controlled drug release. The Raman spectra of each LP component were used to evaluate their contribution in the LP Raman fingerprint. Raman data analysis made it possible to statistically discriminate LPs with different functionalization patterns, showing that each molecular component has an influence in the Raman spectrum of the final LP formulation. Moreover, CLS analysis on Raman data revealed a good level of synthetic reproducibility of the formulations and confirmed their stability within one month from their synthesis, demonstrating the ability of the technique to evaluate the efficacy of LP synthesis using small amount of sample. RS represents a valuable tool for a fast, sensitive and label free biochemical characterization of LPs that could be used for quality control of nanoparticle-based therapeutics.

Molecular MRI-Based Monitoring of Cancer Immunotherapy Treatment Response

Immunotherapy constitutes a paradigm shift in cancer treatment. Its FDA approval for several indications has yielded improved prognosis for cases where traditional therapy has shown limited efficiency. However, many patients still fail to benefit from this treatment modality, and the exact mechanisms responsible for tumor response are unknown. Noninvasive treatment monitoring is crucial for longitudinal tumor characterization and the early detection of non-responders. While various medical imaging techniques can provide a morphological picture of the lesion and its surrounding tissue, a molecular-oriented imaging approach holds the key to unraveling biological effects that occur much earlier in the immunotherapy timeline. Magnetic resonance imaging (MRI) is a highly versatile imaging modality, where the image contrast can be tailored to emphasize a particular biophysical property of interest using advanced engineering of the imaging pipeline. In this review, recent advances in molecular-MRI based cancer immunotherapy monitoring are described. Next, the presentation of the underlying physics, computational, and biological features are complemented by a critical analysis of the results obtained in preclinical and clinical studies. Finally, emerging artificial intelligence (AI)-based strategies to further distill, quantify, and interpret the image-based molecular MRI information are discussed in terms of perspectives for the future.

Optimal Approximation of Fractional Order Brain Tumor Model Using Generalized Laguerre Polynomials

A brain tumor occurs when abnormal cells form within the brain. Glioblastoma (GB) is an aggressive and fast-growing type of brain tumor that invades brain tissue or spinal cord. GB evolves from astrocytic glial cells in the central nervous system. GB can occur at almost any age, but the occurrence increases with advancing age in older adults. Its symptoms may include nausea, vomiting, headaches, or even seizures. GB, formerly known as glioblastoma multiforme, currently has no cure with a high rate of resistance to therapy in clinical treatment. However, treatments can slow tumor progression or alleviate the signs and symptoms. In this paper, a fractional order brain tumor model was considered. The optimal solution of the model was obtained using an optimization method based on operational matrices. The solution to the problem under study was expanded in terms of generalized Laguerre polynomials (GLPs). The study problem was shifted to a system of nonlinear algebraic equations by the use of Lagrange multipliers combined with operational matrices based on GLPs. The analysis of convergence was discussed. In the end, some numerical examples were presented to justify theoretical statements along with the patterns of biological behavior.

Kavain ablates the radio-resistance of IDH-wildtype glioblastoma by targeting LITAF/NF-κB pathway

BACKGROUND

Glioblastoma multiforma (GBM) is the most malignant intrinsic tumor of the central nervous system (CNS), with high morbidity of 3.19/100,000 per year and a poor 5-year survival rate (< 5%) worldwide. Numerous studies have indicated that GBM shows remarkable radioresistance and aggressive recurrence. However, the mechanisms to endow GBM cells with radioresistance are complex and unclear.

METHODS

Cell growth curve and colony formation assays were used to analyze the radioresistance of GBM. Immunoprecipitation and immunoblotting experiments were carried out to analyze protein expression and interaction.

RESULTS

In the present study, we found that LITAF, lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-α factor, is up-regulated both in mRNA and protein in GBM tumors. Meanwhile, we observed that high LITAF expression contributes to radioresistance of GBM cell lines (including U87, U251, DK, and AM38 cells), indicated by knockout or knockdown of LITAF in cells sensitizing them to radiation treatment both in vitro and in vivo. Furthermore, we demonstrated that kavain, an active constituent of Piper methysticum Forst., effectively ablates GSC-like cells' (such as CD133 + U87, U251, DK, and AM38 populations) radioresistance in a LITAF-dependent manner.

CONCLUSION

In mechanism, our results indicated that 1) the elevation of LITAF in GBM cells activates the NF-κB pathway to promote mesenchymal transition, and 2) kavain disturbs STAT6B/LITAF protein interaction and then expels LITAF from the nucleus. Therefore, we consider that kavain may be a potential candidate to develop an irradiation therapy adjuvant for GBM.

Reprogramming systemic and local immune function to empower immunotherapy against glioblastoma

The limited benefits of immunotherapy against glioblastoma (GBM) is closely related to the paucity of T cells in brain tumor bed. Both systemic and local immunosuppression contribute to the deficiency of tumor-infiltrating T cells. However, the current studies focus heavily on the local immunosuppressive tumor microenvironment but not on the co-existence of systemic immunosuppression. Here, we develop a nanostructure named Nano-reshaper to co-encapsulate lymphopenia alleviating agent cannabidiol and lymphocyte recruiting cytokine LIGHT. The results show that Nano-reshaper increases the number of systemic T cells and improves local T-cell recruitment condition, thus greatly increasing T-cell infiltration. When combined with immune checkpoint inhibitor, this therapeutic modality achieves 83.3% long-term survivors without recurrence in GBM models in male mice. Collectively, this work unveils that simultaneous reprogramming of systemic and local immune function is critical for T-cell based immunotherapy and provides a clinically translatable option for combating brain tumors.

Ferritin-Enhanced Direct MicroRNA Detection via Controlled Radical Polymerization

Accurate quantitative detection of tracing nucleic acids remains a great challenge in cancer genetic testing. It is crucial to propose a low-cost and highly sensitive direct gene detection method for cancer prevention and treatment. Herein, this work reports an ultrasensitive biosensor via a ferritin-enhanced atom-transfer radical polymerization (Ft-ATRP) process. Intriguingly, microRNA-21, an early marker of lung cancer, can be detected without being transcribed in advance by an innovative signal amplification strategy using ferritin-mediated aggregation of hydrophilic nitroxide radical monomers as an electrochemical biosensor. The sensor uses peptide nucleic acid probes modified on a gold electrode to accurately bind the target lung cancer marker in the sample, and then ferritin, which is naturally present in human blood, induces Ft-ATRP on the electrode surface under mild conditions. Many of 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical (MATMP) monomers with electrochemical signals are combined into polymeric chains to be modified on target assays. The limit of detection (LOD) of microRNA-21 is as low as 6.03 fM, and the detection concentration ranges from 0.01 to 100 pM (R² = 0.994). The RNA biosensor can realize great performance analysis of complicated samples in simple operation, in addition, the detection process used by the catalyst, polymers containing electrochemical signals, and the electrolyte solution all have good water solubility. The superior performance of the RNA biosensor demonstrates its potential to screen and identify lung cancer in target patients.

CASP4 can be a diagnostic biomarker and correlated with immune infiltrates in gliomas

Background

Gliomas are the most common and invasive malignant tumors that originate in the central nervous system. Currently, the primary treatment modality for gliomas is maximum surgical resection, supplemented by radiotherapy and chemotherapy. However, the long-term survival rate has not signifificantly increased. Pyroptosis is a new form of programmed lytic death that has been recently discovered. Caspase 4 (CASP4) plays a key role in pyroptosis. Many studies have shown that pyroptosis is not only related to inflflammation but is also closely related to the occurrence and development of most tumors. This study aimed to prove that CASP4 has a key role in the mechanism of gliomas.

Methods

We used expression data from The Cancer Genome Atlas and the Chinese Glioma Genome Atlas to explore the relationship between CASP4 expression and glioma prognosis. The differential expression of CASP4 in gliomas and normal tissues was fifirst tested, and then the connection between CASP4 and tumor prognosis was explored. The relationship between CASP4 expression and immune cell infifiltration was also investigated. Finally, the possible pathways were analyzed using Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and Gene Set Enrichment Analysis.

Results

CASP4 was highly expressed and associated with a signifificantly lower survival rate in patients with glioma. It could also inflfluence immune cell infifiltration by releasing cytokines.

Conclusion

CASP4 can be a diagnostic biomarker and is a promising therapeutic target for gliomas.

A NEW HYPOTHESIS IN THE TREATMENT OF RECURRENT GLIOBLASTOMA MULTIFORME (GBM). PART 2: IS THERE AN ALTERNATIVE THERAPY OPTION IN RECURRENT GM WHEN ALL STANDARD TREATMENTS HAVE BEEN EXHAUSTED?

Glioblastoma multiforme (GBM) is the most aggressive and malignant brain tumor. The average survival time for a patient diagnosed with GBM, using standard treatment methods, is several months. Besides the routinely applied treatments such as neurosurgery, radiotherapy, and chemotherapy, progress is being made in the field of oncology, offering hope for improved treatment outcomes. New treatment methods include individualized multimodal immunotherapy (IMI) and modulated electro-hyperthermia. The coauthor of the above series of articles (parts 1 and 2) - A.Cz. presents the concept of a new, potentially breakthrough treatment option for recurrent GBM. A.Cz. was diagnosed with GBM in August 2021. Exhaustion of standard treatment methods, as well as immunotherapy and virotherapy, only provided temporary relief. Unfortunately, after a few months, the disease recurred. Having little to lose, A.Cz. accepted an ablative dose of 2960 MBq (80 mCi) of I131, based on available literature data. Three days before the administration of radioiodine therapy (RIT), A.Cz. prophylactically blocked the thyroid's ability to absorb the radioisotope. In June 2023, approximately 7 weeks after receiving single I131 dose, the MRI examination confirmed a 30% reduction in the tumor's size. Based on this, one can speculate that Iodine-131 therapy may be an alternative treatment option for GBM patients in the future. However, this hypothesis requires confirmation in further clinical studies.

Substrate stiffness regulates the recurrent glioblastoma cell morphology and aggressiveness

Recurrent glioblastoma is highly aggressive with currently no specific treatment regime. Therefore, to identify novel therapeutic targets for recurrent GBM, we used a cellular model developed in our lab from commercially available cell line U87MG and patient-derived cultures that allows the comparison between radiation naïve (Parent) and recurrent GBM cells generated after parent cells are exposed to lethal dose of radiation. Total RNA-seq of parent and recurrent population revealed significant upregulation of cell-ECM interactions pathway in the recurrent population. These results led us to hypothesize that the physical microenvironment contributes to the aggressiveness of recurrent GBM. To verify this, we cultured parent and recurrent GBM cells on collagen-coated polyacrylamide gels mimicking the stiffness of normal brain (Young's modulus E = 0.5kPa) or tumorigenic brain (E = 10kPa) and tissue culture plastic dishes (E ∼ 1 GPa). We found that compared to parent cells, recurrent cells showed higher proliferation, invasion, migration, and resistance to EGFR inhibitor. Using orthotopic GBM mouse model and resection model, we demonstrate that recurrent cells cultured on 0.5kPa had higher in vivo tumorigenicity and recurrent disease progression than parent cells, whereas these differences were insignificant when parent and recurrent cells were cultured on plastic substrates. Furthermore, recurrent cells on 0.5kPa showed high expression of ECM proteins like Collagen, MMP2 and MMP9. These proteins were also significantly upregulated in recurrent patient biopsies. Additionally, the brain of mice injected with recurrent cells grown on 0.5kPa showed higher Young's moduli suggesting the ability of these cells to make the surrounding ECM stiffer. Total RNA-seq of parent and recurrent cells grown on plastic and 0.5kpa identified PLEKHA7 significantly upregulated specifically in recurrent cells grown on 0.5 kPa substrate. PLEKHA7 was also found to be high in recurrent GBM patient biopsies. Accordingly, PLEKHA7 knockdown reduced invasion and survival of recurrent GBM cells. Together, these data provide an in vitro model system that captures the observed in vivo and clinical behavior of recurrent GBM by mimicking mechanical microenvironment and identifies PLEKHA7 as a novel potential target for recurrent GBM.

A NEW HYPOTHESIS IN THE TREATMENT OF RECURRENT GLIOBLASTOMA MULTIFORME (GBM). PART 1: INTRODUCTION

Modern treatment of glioblastoma multiforme (GBM) is based on neurosurgical methods combined with radiotherapy and chemotherapy. The prognosis for patients with GBM is extremely poor. Often, complete removal of the tumor is impossible and it often recurs. Therefore, in addition to standard regimens, modern methods such as modulated electrohyperthermia, monoclonal antibodies and individualised multimodal immunotherapy (IMI) based on vaccines and oncolytic viruses are also used in the treatment of GBM. Radioiodine therapy (RIT) also holds out hope for an effective treatment of this extremely aggressive brain tumor. The expression of the sodium iodide symporter (NIS) gene has been proven to have a positive effect on the treatment of selected cancers. Research confirm the presence of expression of this gene in GBM cells, although only in animal studies. Is it possible and therapeutically effective to treat GBM with RIT without the use of an exogenous NIS gene? The safety of therapy is relevant, as the only more serious adverse effect may be hypothyroidism. The use of RIT requires further clinical studies in patients. Perhaps it is worth revolutionizing GBM therapy to give sufferers a "new life".

MiR-195 connects lncRNA RUNX1-IT1 and cyclin D1 to regulate the proliferation of glioblastoma cells

AIMS

LncRNA RUNX1-IT1 has been characterized as a tumor suppressive lncRNA in several cancers, while its role in glioblastoma (GBM) is unknown. This study aimed to investigate the potential involvement of RUNX1-IT1 in GBM.

METHODS

Expression of RUNX1-IT1 in GBM tissues and paired non-tumor tissues was determined by RT-qPCR. The interaction between RUNX1-IT1 and miR-195 was analyzed by dual luciferase activity assay. Overexpression of RUNX1-IT1 and miR-195 was achieved in GBM cells to explore the interaction between them. The effects of RUNX1-IT1 and miR-195 overexpression on the expression of cyclin D1 were analyzed by RT-qPCR and Western blot. Cell proliferation was analyzed by CCK-8 assay.

RESULTS

RUNX1-IT1 was upregulated in GBM. RUNX1-IT1 and miR-195 interacted with each other, but failed to regulate the expression of each other. Overexpression of RUNX1-IT1 resulted in the upregulation of cyclin D1, and also reduced the effects of miR-195 overexpression on cyclin D1 expression. RUNX1-IT1 and cyclin overexpression increased cell proliferation, while miR-195 overexpression decreased cell proliferation. In addition, RUNX1-IT1 overexpression reduced the effects of miR-195 overexpression on cell proliferation.

CONCLUSIONS

RUNX1-IT1 may sponge miR-195 to upregulate cyclin D1, thereby increasing the proliferation of glioblastoma cells.

Mesenchymal stem cells loaded with Ad5-Ki67/IL-15 enhance oncolytic adenovirotherapy in experimental glioblastoma

The conventional treatment strategy for glioblastoma multiforme (GBM) is surgical resection followed by radiotherapy and chemotherapy. Oncolytic adenovirotherapy is a promising alternative to conventional treatment. It provides a strategic combination of direct tumor-specific cell lysis and antitumor immune promotion. Despite advances in oncolytic adenovirotherapy, limitations remain, including the host's antiviral immune response and insufficient viral infiltration into the tumor. Mesenchymal stem cells (MSCs) have emerged as innovative vehicles due to their ability to home to tumors and protect oncolytic adenovirus (oAd) from the host antiviral immune system. We developed an Ad5-Ki67/IL-15 driven by the Ki67 promoter and armed with IL-15. Using this construction, viral replication is related to Ki67 expression in GBM cells. Thus, MSCs with background Ki67 expression can help deliver higher levels of oncolytic viruses and can strike a balance between viral load and cell viability. Using in vitro assay, MSCs loaded with Ad5-Ki67/IL-15 (MSC-Ad5) were shown to exert anti-glioblastoma efficacy. Compared to previous attempts at direct intratumoral injection of high doses of viruses, MSCs loaded with lower doses of viruses exerted stronger therapeutic effects and promoted macrophage/microglia infiltration in a Vivo model. Collectively, our results suggest that the use of MSCs as vehicles of oAd is a promising strategy and deserves further investigation for the treatment of GBM.

LncRNA LINC01018/miR-942-5p/KNG1 axis regulates the malignant development of glioma in vitro and in vivo

AIMS

Since the inhibitory effect of KNG1 on glioma has been proved, this study further explores the regulation of the lncRNA/miRNA axis on KNG1 in glioma.

METHODS

The miRNAs that target KNG1 and the lncRNA that targets miR-942-5p were predicted by bioinformatics analysis and verified by experiments. The correlations between miR-942-5p and the survival of patients and between KNG1 and miR-942-5p were analyzed. After transfection, cell migration, invasion, proliferation, and cell cycle were detected through wound healing, Transwell, colony formation, and flow cytometry assays. A mouse subcutaneous xenotransplanted tumor model was established. The expressions of miR-942-5p, KNG1, LINC01018, and related genes were evaluated by quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR), Western blot, or immunohistochemistry.

RESULTS

MiR-942-5p targeted KNG1, and LINC01018 sponged miR-942-5p. The high survival rate of patients was related to low miR-942-5p level. MiR-942-5p was highly expressed, whereas KNG1 was lowly expressed in glioma. MiR-942-5p was negatively correlated with KNG1. Silent LINC01018 or KNG1 and miR-942-5p mimic enhanced the migration, invasion, and proliferation of glioma cells, and regulated the expressions of metastasis-related and proliferation-related genes. LINC01018 knockdown and miR-942-5p mimic promoted glioma tumor growth in mice. The levels of miR-942-5p and KNG1 were decreased by LINC01018 knockdown, and LINC01018 expression was suppressed by miR-942-5p mimic. MiR-942-5p inhibitor, KNG1, and LINC01018 had the opposite effect to miR-942-5p mimic.

CONCLUSION

LINC01018/miR-942-5p/KNG1 pathway regulates the development of glioma cells in vitro and in vivo.

Role of the Ca2+ channel α2δ-1 auxiliary subunit in proliferation and migration of human glioblastoma cells

The overexpression of α2δ-1 is related to the development and degree of malignancy of diverse types of cancer. This protein is an auxiliary subunit of voltage-gated Ca2+ (CaV) channels, whose expression favors the trafficking of the main pore-forming subunit of the channel complex (α1) to the plasma membrane, thereby generating an increase in Ca2+ entry. Interestingly, TLR-4, a protein belonging to the family of toll-like receptors that participate in the inflammatory response and the transcription factor Sp1, have been linked to the progression of glioblastoma multiforme (GBM). Therefore, this report aimed to evaluate the role of the α2δ-1 subunit in the progression of GBM and investigate whether Sp1 regulates its expression after the activation of TLR-4. To this end, the expression of α2δ-1, TLR-4, and Sp1 was assessed in the U87 human glioblastoma cell line, and proliferation and migration assays were conducted using different agonists and antagonists. The actions of α2δ-1 were also investigated using overexpression and knockdown strategies. Initial luciferase assays and Western blot analyses showed that the activation of TLR-4 favors the transcription and expression of α2δ-1, which promoted the proliferation and migration of the U87 cells. Consistent with this, overexpression of α2δ-1, Sp1, and TLR-4 increased cell proliferation and migration, while their knockdown with specific siRNAs abrogated these actions. Our data also suggest that TLR-4-mediated regulation of α2δ-1 expression occurs through the NF-kB signaling pathway. Together, these findings strongly suggest that the activation of TLR-4 increases the expression of α2δ-1 in U87 cells, favoring their proliferative and migratory potential, which might eventually provide a theoretical basis to examine novel biomarkers and molecular targets for the diagnosis and treatment of GBM.

2,5-Bis(2,2,2-trifluoroethoxy)phenyl-tethered 1,3,4-Oxadiazoles Derivatives: Synthesis, In Silico Studies, and Biological Assessment as Potential Candidates for Anti-Cancer and Anti-Diabetic Agent

In the present work, a series of new 1-{5-[2,5-bis(2,2,2-trifluoroethoxy)phenyl]-1,3,4-oxadiazol-3-acetyl-2-aryl-2H/methyl derivatives were synthesized through a multistep reaction sequence. The compounds were synthesized by the condensation of various aldehydes and acetophenones with the laboratory-synthesized acid hydrazide, which afforded the Schiff's bases. Cyclization of the Schiff bases yielded 1,3,4-oxadiazole derivatives. By spectral analysis, the structures of the newly synthesized compounds were elucidated, and further, their anti-cancer and anti-diabetic properties were investigated. To examine the dynamic behavior of the candidates at the binding site of the protein, molecular docking experiments on the synthesized compounds were performed, followed by a molecular dynamic simulation. ADMET (chemical absorption, distribution, metabolism, excretion, and toxicity) prediction revealed that most of the synthesized compounds follow Lipinski's rule of 5. The results were further correlated with biological studies. Using a cytotoxic assay, the newly synthesized 1,3,4-Oxadiazoles were screened for their in vitro cytotoxic efficacy against the LN229 Glioblastoma cell line. From the cytotoxic assay, the compounds 5b, 5d, and 5m were taken for colony formation assay and tunnel assay have shown significant cell apoptosis by damaging the DNA of cancer cells. The in vivo studies using a genetically modified diabetic model, Drosophila melanogaster, indicated that compounds 5d and 5f have better anti-diabetic activity among the different synthesized compounds. These compounds lowered the glucose levels significantly in the tested model.

The miR-429 suppresses proliferation and migration in glioblastoma cells and induces cell-cycle arrest and apoptosis via modulating several target genes of ERBB signaling pathway

BACKGROUND

Glioblastoma multiforme (GBM) is an aggressive and lethal brain cancer, which is incurable with standard cancer treatments. miRNAs have great potential to be used for gene therapy due to their ability to modulate several target genes simultaneously. We found miR-429 is downregulated in GBM and has several predicted target genes from the ERBB signaling pathway using bioinformatics tools. ERBB is the most over-activated genetic pathway in GBM patients, which is responsible for augmented cell proliferation and migration in GBM.

METHODS AND RESULTS

Here, miR-429 was overexpressed using lentiviral vectors in U-251 and U-87 GBM cells and it was observed that the expression level of several oncogenes of the ERBB pathway, EGFR, PIK3CA, PIK3CB, KRAS, and MYC significantly decreased, as shown by real-time PCR and western blotting. Using the luciferase assay, we showed that miR-429 directly targets MYC, BCL2, and EGFR. In comparison to scrambled control, miR-429 had a significant inhibitory effect on cell proliferation and migration as deduced from MTT and scratch wound assays and induced cell-cycle arrest and apoptosis in flow cytometry.

CONCLUSIONS

Altogether, miR-429 seems to be an efficient suppressor of the ERBB genetic signaling pathway and a potential therapeutic for GBM.

P2Y12 receptor antagonism inhibits proliferation, migration and leads to autophagy of glioblastoma cells

Glioblastoma (GBM) is the most aggressive and lethal among the primary brain tumors, with a low survival rate and resistance to radio and chemotherapy. The P2Y₁₂ is an adenosine diphosphate (ADP) purinergic chemoreceptor, found mainly in platelets. In cancer cells, its activation has been described to induce proliferation and metastasis. Bearing in mind the need to find new treatments for GBM, this study aimed to investigate the role of the P2Y₁₂R in the proliferation and migration of GBM cells, as well as to evaluate the expression of this receptor in patients' data obtained from the TCGA data bank. Here, we used the P2Y₁₂R antagonist, ticagrelor, which belongs to the antiplatelet agent's class. The different GBM cells (cell line and patient-derived cells) were treated with ticagrelor, with the agonist, ADP, or both, and the effects on cell proliferation, colony formation, ADP hydrolysis, cell cycle and death, migration, and cell adhesion were analyzed. The results showed that ticagrelor decreased the viability and the proliferation of GBM cells. P2Y₁₂R antagonism also reduced colony formation and migration potentials, with alterations on the expression of metalloproteinases, and induced autophagy in GBM cells. Changes were observed at the cell cycle level, and only the U251 cell line showed a significant reduction in the ADP hydrolysis profile. TCGA data analysis showed a higher expression of P2Y₁₂R in gliomas samples when compared to the other tumors. These data demonstrate the importance of the P2Y₁₂ receptor in gliomas development and reinforce its potential as a pharmacological target for glioma treatment.

Anoctamins and Calcium Signalling: An Obstacle to EGFR Targeted Therapy in Glioblastoma?

Glioblastoma is the most common form of high-grade glioma in adults and has a poor survival rate with very limited treatment options. There have been no significant advancements in glioblastoma treatment in over 30 years. Epidermal growth factor receptor is upregulated in most glioblastoma tumours and, therefore, has been a drug target in recent targeted therapy clinical trials. However, while many inhibitors and antibodies for epidermal growth factor receptor have demonstrated promising anti-tumour effects in preclinical models, they have failed to improve outcomes for glioblastoma patients in clinical trials. This is likely due to the highly plastic nature of glioblastoma tumours, which results in therapeutic resistance. Ion channels are instrumental in the development of many cancers and may regulate cellular plasticity in glioblastoma. This review will explore the potential involvement of a class of calcium-activated chloride channels called anoctamins in brain cancer. We will also discuss the integrated role of calcium channels and anoctamins in regulating calcium-mediated signalling pathways, such as epidermal growth factor signalling, to promote brain cancer cell growth and migration.

Hypoxia Enhances Glioma Resistance to Sulfasalazine-Induced Ferroptosis by Upregulating SLC7A11 via PI3K/AKT/HIF-1α Axis

Glioma is the most common primary brain tumor, with a high rate of recurrence and treatment resistance. Glioblastoma is highly invasive, infiltrating surrounding brain parenchyma, and is known to cause intracranial metastasis resulting in a dismal prognosis. Hypoxia contributes significantly to chemo- and radiotherapy resistance in cancer. Ferroptosis is a nonapoptotic oxidative cell death that has been identified as a potential anticancer mechanism. Sulfasalazine (SAS) activates ferroptosis and plays a potential role in tumor treatment. However, the relationship between hypoxia and SAS resistance has not been elucidated. This study is aimed at investigating the role of hypoxia in SAS-induced ferroptosis and the underlying mechanisms. Here, we found that hypoxia significantly suppressed SAS-induced ferroptosis by upregulating SLC7A11 expression in the U87 and U251 glioma cell lines. Hypoxia promotes SLC7A11 expression by enhancing the PI3K/AKT/HIF-1α pathway. The AKT inhibitor MK-2206 and HIF-1α inhibitor PX-478 significantly reversed this effect. In addition, under normoxia, PX-478 induced a higher lipid peroxidation level by decreasing SLC7A11 expression in the U87 and U251 cells but could not induce cell death directly; it could significantly enhance the tumor cell killing effect of SAS. In vivo, the combination of PX-478 and SAS had a coordinated synergistic effect on anticancer activity, as revealed by subcutaneous and orthotopic xenograft mouse models. In conclusion, hypoxia enhanced glioma resistance to SAS-induced ferroptosis by upregulating SLC7A11 via activating the PI3K/AKT/HIF-1α axis. Combination therapy with PX-478 and SAS may be a potential strategy against glioma.

DNA5mC Regulator-Mediated Molecular Clusters and Tumor Microenvironment Signatures in Glioblastoma

Growing evidence links DNA methylation to tumor immunity. The impact of DNA methylation (5 mC) on the microenvironment surrounding tumors and immunotherapy remains to be clarified. Through clustering gene expression of 20 DNA methylation regulators, this study aimed at systematically analyzing DNA methylation regulator patterns and tumor microenvironment characteristics of TCGA-GBM patients. Various subtypes of glioblastoma exhibit different tumor microenvironments and DNA methylation patterns. Each DNA methylation modification was then assigned a DNA methylation score (DMS). High DMS was associated with a good prognosis. In contrast, the low DMS group had a relatively low survival rate. A correlation was also found between high DMS and enhanced immunotherapy efficacy in two immune checkpoint blocking treatment cohorts. To conclude, identifying DNA methylation regulation patterns may prove critical to understanding glioblastoma progression and differentiation, as well as future therapeutic targets.

Therapeutic efficacy of 166Holmium siloxane in microbrachytherapy of induced glioblastoma in minipig tumor model

Glioblastoma is considered the most common malignant primary tumor of central nervous system. In spite of the current standard and multimodal treatment, the prognosis of glioblastoma is poor. For this reason, new therapeutic approaches need to be developed to improve the survival time of the glioblastoma patient. In this study, we performed a preclinical experiment to evaluate therapeutic efficacy of 166Ho microparticle suspension administered by microbrachytherapy on a minipig glioblastoma model. Twelve minipigs were divided in 3 groups. Minipigs had injections into the tumor, containing microparticle suspensions of either 166Ho (group 1; n = 6) or 165Ho (group 2; n = 3) and control group (group 3; n = 3). The survival time from treatment to euthanasia was 66 days with a good state of health of all minipigs in group 1. The median survival time from treatment to tumor related death were 8.6 and 7.3 days in groups 2 and control, respectively. Statistically, the prolonged life of group 1 was significantly different from the two other groups (p < 0.01), and no significant difference was observed between group 2 and control (p=0.09). Our trial on the therapeutic effect of the 166Ho microparticle demonstrated an excellent efficacy in tumor control. The histological and immunohistochemical analysis showed that the efficacy was related to a severe 166Ho induced necrosis combined with an immune response due to the presence of the radioactive microparticles inside the tumors. The absence of reflux following the injections confirms the safety of the injection device.

Anticancer effects of ABTL0812, a clinical stage drug inducer of autophagy-mediated cancer cell death, in glioblastoma models

Background

Glioblastoma multiforme (GBM) is the most malignant adult brain tumor. Current standard of care treatments have very limited efficacy, being the patients´ overall survival 14 months and the 2-year survival rate less than 10%. Therefore, the treatment of GBM is an urgent unmet clinical need.

Methods

The aim of this study was to investigate in vitro and in vivo the potential of ABTL0812, an oral anticancer compound currently in phase II clinical stage, as a novel therapy for GBM.

Results

We showed that ABTL0812 inhibits cell proliferation in a wide panel of GBM cell lines and patient-derived glioblastoma stem cells (GSCs) with half maximal inhibitory concentrations (IC50s) ranging from 15.2 µM to 46.9 µM. Additionally, ABTL0812 decreased GSCs neurosphere formation. GBM cells aggressiveness is associated with a trans-differentiation process towards a less differentiated phenotype known as proneural to mesenchymal transition (PMT). ABTL0812 was shown to revert PMT and induce cell differentiation to a less malignant phenotype in GBM cell lines and GSCs, and consequently reduced cell invasion. As previously shown in other cancer types, we demonstrated that the molecular mechanism of action of ABTL0812 in glioblastoma involves the inhibition of Akt/mTORC1 axis by overexpression of TRIB3, and the activation of endoplasmic reticulum (ER) stress/unfolded protein response (UPR). Both actions converge to induce autophagy-mediated cell death. ABTL0812 anticancer efficacy was studied in vivo using subcutaneous and orthotopic intra-brain xenograft tumor models. We demonstrated that ABTL0812 impairs tumor growth and increases disease-free survival and overall survival of mice. Furthermore, the histological analysis of tumors indicated that ABTL0812 decreases angiogenesis. Finally, we investigated the combination of ABTL0812 with the standard of care treatments for GBM radiotherapy and temozolomide in an orthotopic model, detecting that ABTL0812 potentiates the efficacy of both treatments and that the strongest effect is obtained with the triple combination of ABTL0812+radiotherapy+temozolomide.

Conclusions

Overall, the present study demonstrated the anticancer efficacy of ABTL0812 as single agent and in combination with the GBM standard of care treatments in models of glioblastoma and supports the clinical investigation of ABTL0812 as a potential novel therapy for this aggressive brain tumor type.

Tau Protein as Therapeutic Target for Cancer? Focus on Glioblastoma

Despite being extensively studied for several decades, the microtubule-associated protein Tau has not finished revealing its secrets. For long, Tau has been known for its ability to promote microtubule assembly. A less known feature of Tau is its capability to bind to cancer-related protein kinases, suggesting a possible role of Tau in modulating microtubule-independent cellular pathways that are associated with oncogenesis. With the intention of finding new therapeutic targets for cancer, it appears essential to examine the interaction of Tau with these kinases and their consequences. This review aims at collecting the literature data supporting the relationship between Tau and cancer with a particular focus on glioblastoma tumors in which the pathological significance of Tau remains largely unexplored. We will first treat this subject from a mechanistic point of view showing the pivotal role of Tau in oncogenic processes. Then, we will discuss the involvement of Tau in dysregulating critical pathways in glioblastoma. Finally, we will outline promising strategies to target Tau protein for the therapy of glioblastoma.

Smart Nanoformulations for Brain Cancer Theranostics: Challenges and Promises

Despite their low prevalence, brain tumors are among the most lethal cancers. They are extremely difficult to diagnose, monitor and treat. Conventional anti-cancer strategies such as radio- and chemotherapy have largely failed, and to date, the development of even a single effective therapeutic strategy against central nervous system (CNS) tumors has remained elusive. There are several factors responsible for this. Brain cancers are a heterogeneous group of diseases with variable origins, biochemical properties and degrees of invasiveness. High-grade gliomas are amongst the most metastatic and invasive cancers, which is another reason for therapeutic failure in their case. Moreover, crossing the blood brain and the blood brain tumor barriers has been a significant hindrance in the development of efficient CNS therapeutics. Cancer nanomedicine, which encompasses the application of nanotechnology for diagnosis, monitoring and therapy of cancers, is a rapidly evolving field of translational medicine. Nanoformulations, because of their extreme versatility and manipulative potential, are emerging candidates for tumor targeting, penetration and treatment in the brain. Moreover, suitable nanocarriers can be commissioned for theranostics, a combinatorial personalized approach for simultaneous imaging and therapy. This review first details the recent advances in novel bioengineering techniques that provide promising avenues for circumventing the hurdles of delivering the diagnostic/therapeutic agent to the CNS. The authors then describe in detail the tremendous potential of utilizing nanotechnology, particularly nano-theranostics for brain cancer imaging and therapy, and outline the different categories of recently developed next-generation smart nanoformulations that have exceptional potential for making a breakthrough in clinical neuro-oncology therapeutics.

Characterization of EGFR-reprogrammable temozolomide-resistant cells in a model of glioblastoma

Temozolomide (TMZ) resistance is a major clinical challenge for glioblastoma (GBM). O⁶-methylguanine-DNA methyltransferase (MGMT) mediated DNA damage repair is a key mechanism for TMZ resistance. However, MGMT-null GBM patients remain resistant to TMZ, and the process for resistance evolution is largely unknown. Here, we developed an acquired TMZ resistant xenograft model using serial implantation of MGMT-hypermethylated U87 cells, allowing the extraction of stable, TMZ resistant (TMZ-R) tumors and primary cells. The derived tumors and cells exhibited stable multidrug resistance both in vitro and in vivo. Functional experiments, as well as single-cell RNA sequencing (scRNA-seq), indicated that TMZ treatment induced cellular heterogeneity including quiescent cancer stem cells (CSCs) in TMZ-R tumors. A subset of these were labeled by NES⁺/SOX2⁺/CADM1⁺ and demonstrated significant advantages for drug resistance. Further study revealed that Epidermal Growth Factor Receptor (EGFR) deficiency and diminished downstream signaling may confer this triple positive CSCs subgroup’s quiescent phenotypes and chemoresistance. Continuous EGF treatment improved the chemosensitivity of TMZ-R cells both in vitro and in vivo, mechanically reversing cell cycle arrest and reduced drug uptake. Further, EGF treatment of TMZ-R tumors favorably normalized the response to TMZ in combination therapy. Here, we characterize a unique subgroup of CSCs in MGMT-null experimental glioblastoma, identifying EGF + TMZ therapy as a potential strategy to overcome cellular quiescence and TMZ resistance, likely endowed by deficient EGFR signaling.

New Directions in the Therapy of Glioblastoma

Glioblastoma is the most common histologic type of all gliomas and contributes to 57.3% of all cases. Despite the standard management based on surgical resection and radiotherapy, it is related to poor outcome, with a 5-year relative survival rate below 6.9%. In order to improve the overall outcome for patients, the new therapeutic strategies are needed. Herein, we describe the current state of knowledge on novel targeted therapies in glioblastoma. Based on recent studies, we compared treatment efficacy measured by overall survival and progression-free survival in patients treated with selected potential antitumor drugs. The results of the application of the analyzed inhibitors are highly variable despite the encouraging conclusions of previous preclinical studies. This paper focused on drugs that target major glioblastoma kinases. As far, the results of some BRAF inhibitors are favorable. Vemurafenib demonstrated a long-term efficacy in clinical trials while the combination of dabrafenib and trametinib improves PFS compared with both vemurafenib and dabrafenib alone. There is no evidence that any MEK inhibitor is effective in monotherapy. According to the current state of knowledge, BRAF and MEK inhibition are more advantageous than BRAF inhibitor monotherapy. Moreover, mTOR inhibitors (especially paxalisib) may be considered a particularly important group. Everolimus demonstrated a partial response in a significant proportion of patients when combined with bevacizumab, however its actual role in the treatment is unclear. Neither nintedanib nor pemigatinib were efficient in treatment of GBM. Among the anti-VEGF drugs, bevacizumab monotherapy was a well-tolerated option, significantly associated with anti-GBM activity in patients with recurrent GBM. The efficacy of aflibercept and pazopanib in monotherapy has not been demonstrated. Apatinib has been proven to be effective and tolerable by a single clinical trial, but more research is needed. Lenvatinib is under trial. Finally, promising results from a study with regorafenib may be confirmed by the ongoing randomized AGILE trial. The studies conducted so far have provided a relatively wide range of drugs, which are at least well tolerated and demonstrated some efficacy in the randomized clinical trials. The comprehensive understanding of the molecular biology of gliomas promises to further improve the treatment outcomes of patients.

N6-methyladenosine-modified HOTAIRM1 promotes vasculogenic mimicry formation in glioma

Vasculogenic mimicry (VM) has been reported to accelerate angiogenesis in malignant tumors, yet the mechanism underlying VM has not been fully elucidated. N6-methyladenosine (m6A) mainly modulates mRNA fate and affects multiple tumorigenesis. Here, we aimed to investigate m6A-modified HOXA transcript antisense RNA myeloid-specific 1 (HOTAIRM1) in the regulation of glioma-associated VM formation. Gene expression was analyzed by quantitative RT-PCR. Cell viability, metastases, and VM formation capacity were determined by CCK-8, migration and invasion, as well as tube formation assays, respectively. The function and mechanisms of m6A-modified HOTAIRM1 were defined through liquid chromatography-tandem mass spectrometry m6A quantification, methylated RNA immunoprecipitation sequencing, RNA stability assays, and RNA pull-down experiments. A glioma xenograft mouse model was further established for VM evaluation in vivo. The results showed that HOTAIRM1, methyltransferase-like 3 (METTL3), and insulin-like growth factor binding protein 2 (IGFBP2) were upregulated in glioma tissues and cell lines. HOTAIRM1 functions as an oncogene in glioma progression; however, knockdown of HOTAIRM1 significantly reduced cell viability, migration, invasion, and VM formation. Notably, METTL3-dependent m6A modification enhanced HOTAIRM1 mRNA stability, whereas knockdown of METTL3 deficiency significantly suppressed VM in glioma. Moreover, HOTAIRM1 was found to bind IGFBP2, and HOTAIRM1 deficiency blocked glioma progression and VM formation in vivo. Our results indicated that METTL3-dependent m6A-modified HOTAIRM1 promoted VM formation in glioma.

Utilizing Immunoinformatics to Target Brain Tumors; An Aid to Current Neurosurgical Practice

Context: Despite major advancements in the field, the current neurosurgical practice requires an interdisciplinary approach. It is known that surgical practice and other cancer-eliminating treatments can be combined for optimal results. However, recent attempts have failed to address many debilitating conditions, indicating an emergent need for novel interdisciplinary therapeutic approaches. Evidence Acquisition: We searched PubMed and Google Scholar for the keywords “immunoinformatics,” “in silico,” “neurology,” and “neurosurgery.” Without time restriction. Results: The immune system is versatile because it is involved in physiological brain function and affects the course of central nervous system (CNS) disease and infection. A novel approach combines neurosurgery and immunoinformatics for optimal results. For instance, brain tumors, such as glioblastoma multiforme (GBM), are still associated with a severely reduced survival of patients, and resection of tumors may provide little help. In silico approaches could help to identify molecular pathways and design immunotherapies for such conditions at a significantly increased speed compared to traditional vaccinology approaches. Conclusions: The neurosurgical practice could be affected by different infectious organisms. These organisms can be targeted by in silico vaccinology techniques. Here, we provide a brief overview of bioinformatics/immunoinformatics and discuss the possible role of immunoinformatics in neurosurgery. In light of the current Coronavirus disease-2019 (COVID-19) epidemic, projections for future studies are also included.

Parvifloron D-based potential therapy for glioblastoma: Inducing apoptosis via the mitochondria dependent pathway

Glioblastoma (GB) is the most malignant and frequent primary tumor of the central nervous system. The lack of diagnostic tools and the poor prognosis associated with this tumor type leads to restricted and limited options of treatment, namely surgical resection and radio-chemotherapy. However, despite these treatments, in almost all cases, patients experience relapse, leading to survival rates shorter than 5 years (∼15-18 months after diagnosis). Novel therapeutic approaches are urgently required (either by discovering new medicines or by repurposing drugs) to surpass the limitations of conventional treatments and improve patients' survival rate and quality of life. In the present work, we investigated the antitumor potential of parvifloron D (ParvD), a drug lead of natural origin, in a GB cell line panel. This natural drug lead induced G2/M cell cycle arrest and apoptosis via activation of the intrinsic mitochondria-dependent pathway. Moreover, the necessary doses of ParvD to induce pronounced inhibitory effects were substantially lower than that of temozolomide (TMZ, first-line treatment) required to promote comparable effects. Therefore, ParvD may have the potential to overcome the resistance related to TMZ and contribute to the pursuit of hopeful treatments based on ParvD as a drug lead for future chemotherapeutics.

Hyaluronic Acid Scaffolds for Loco-Regional Therapy in Nervous System Related Disorders

Hyaluronic acid (HA) is a Glycosaminoglycan made of disaccharide units containing N-acetyl-D-glucosamine and glucuronic acid. Its molecular mass can reach 10 MDa and its physiological properties depend on its polymeric property, polyelectrolyte feature and viscous nature. HA is a ubiquitous compound found in almost all biological tissues and fluids. So far, HA grades are produced by biotechnology processes, while in the human organism it is a major component of the extracellular matrix (ECM) in brain tissue, synovial fluid, vitreous humor, cartilage and skin. Indeed, HA is capable of forming hydrogels, polymer crosslinked networks that are very hygroscopic. Based on these considerations, we propose an overview of HA-based scaffolds developed for brain cancer treatment, central and peripheral nervous systems, discuss their relevance and identify the most successful developed systems.

Surgical Treatment of Glioblastoma: State-of-the-Art and Future Trends

Glioblastoma (GBM) is a highly aggressive disease and is associated with poor prognosis despite treatment advances in recent years. Surgical resection of tumor remains the main therapeutic option when approaching these patients, especially when combined with adjuvant radiochemotherapy. In the present study, we conducted a comprehensive literature review on the state-of-the-art and future trends of the surgical treatment of GBM, emphasizing topics that have been the object of recent study.

Long non-coding RNA LINC01018 inhibits human glioma cell proliferation and metastasis by directly targeting miRNA-182-5p

AIM

Accumulating evidence suggests that lncRNAs are potential biomarkers and key regulators of tumor development and progression. However, the precise function of most lncRNAs in glioma remains unknown. In this study, we explored the role of long intergenic non-protein coding RNA 1018 (LINC01018) in human glioma.

METHODS

Expression levels of LINC01018 and miR-182-5p in clinical glioma tissues and cell lines were detected by quantitative real-time PCR (qRT-PCR). Cell proliferation, migration, and invasion were determined by Cell Counting Kit-8 (CCK-8) assay and Transwell assay. Epithelial-mesenchymal transition (EMT) related proteins were measured by Western blotting. Direct relationship between LINC01018 and miR-182-5p was tested by dual-luciferase reporter assay, RNA immunoprecipitation assay (RIP), and rescue assays. Lastly, bioinformatics analyses were conducted to predict the downstream factors of LINC01018/miR-182-5p axis in glioma.

RESULTS

LINC01018 was significantly down-regulated in glioma tissues and cell lines. Overexpression of LINC01018 dramatically inhibited cell proliferation, migration, and invasion and reverse EMT process in glioma. LINC01018 directly target to miR-182-5p. Forced up-regulation of miR-182-5p reversed the inhibitory effects on proliferative and metastatic abilities of glioma cells with LINC01018 overexpression. Lastly, the bioinformatics analyses revealed that LINC01018/miR-182-5p axis mediated a cluster of downstream genes (ADRA2C, RAB6B, RAB27B, RAPGEF5, STEAP2, TAGLN3, and UNC13C), which were potential key factors in the development of glioma.

CONCLUSION

LINC01018 inhibits cell proliferation and metastasis in human glioma by targeting miR-182-5p, and should be considered as a potential therapeutic target in this cancer.

An N-heterocyclic carbene iridium(III) complex as a potent anti-cancer stem cell therapeutic

Cancer stem cells (CSCs) represent a difficult to treat cellular niche within tumours due to their unique characteristics, which give them a high propensity for resistance to classical anti-cancer treatments and the ability to repopulate the tumour mass. An attribute that may be implicated in the high rates of recurrence of certain tumours. However, other characteristics specific to these cells, such as their high dependence on mitochondria, may be exploited for the development of new therapeutic agents that are effective against the niche. As such, a previously described phosphorescent N-heterocyclic carbene iridium(III) compound which showed a high level of cytotoxicity against classical tumour cell lines with mitochondria-specific effects was studied for its potential against CSCs. The results showed a significantly higher level of activity against several CSC lines compared to non-CSCs. Mitochondrial localisation and superoxide production were confirmed. Although the cell death involved caspase activation, their role in cell death was not definitive, with a potential implication of other, non-apoptotic pathways shown. A cytostatic effect of the compound was also displayed at low mortality doses. This study thus provides important insights into the mechanisms and the potential for this class of molecule in the domain of anti-CSC therapeutics.

The Role of Apparent Diffusion Coefficient Values in Glioblastoma: Differentiating Tumor Progression Versus Treatment-Related Changes

OBJECTIVE

Glioblastoma represents the most common primary brain malignancy with a median survival of 15 months. Follow-up examinations are crucial to establish the presence of tumor recurrence, as well as treatment-associated changes such as ischemic infarction and radiation effects. Even though magnetic resonance imaging is a valuable tool, a histopathological diagnosis is often required because of imaging overlap between tumor recurrence and treatment associated changes. We set out to measure the apparent diffusion coefficient (ADC) values of the lesions in magnetic resonance imaging scans of treated glioblastoma patients to investigate if ADC values could accurately differentiate between tumor progression, radiation-related changes, and ischemic infarctions.

METHODS

We evaluated ADC values among 3 groups, patients with tumor progression, radiation necrosis, and ischemic infarctions. The regions of interest were placed in the areas of greatest hypointensity among solid lesions using the ADC maps, excluding areas with necrotic, cystic, or hemorrhagic changes. The ADC values of the contralateral normal appearing white matter were also measured as the reference value for each patient. The relative ADC (rADC) values were measured for all 3 groups. Comparison between lesions and normal white matter was evaluated by Wilcoxon signed test.

RESULTS

A total of 157 patients were included in the study; 49 patients classified as tumor progression, 58 patients as radiation necrosis, and 50 patients as ischemic infarctions. The mean ± SD ADC value was 752.8 ± 132.5 for tumor progression, 479.0 ± 105.2 for radiation-related changes, and 250.1 ± 57.2 for ischemic infarctions. The mean ± SD rADC value was 1.07 ± 0.22 for tumor progression, 0.66 ± 0.14 for radiation necrosis, and 0.34 ± 0.08 for ischemic infarctions. The mean rADC values were significantly higher in tumor progression, compared with both radiation necrosis and ischemic changes (P < 0.001).

CONCLUSIONS

The present study demonstrates that ADC values are a helpful tool to differentiate between tumor progression, radiation necrosis, and posttreatment ischemic changes.

Exploring the role of nanomedicines for the therapeutic approach of central nervous system dysfunction: At a glance

In recent decades, research scientists, molecular biologists, and pharmacologists have placed a strong emphasis on cutting-edge nanostructured materials technologies to increase medicine delivery to the central nervous system (CNS). The application of nanoscience for the treatment of neurodegenerative diseases (NDs) such as Alzheimer’s disease (AD), Parkinson’s disease (PD), multiple sclerosis (MS), Huntington’s disease (HD), brain cancer, and hemorrhage has the potential to transform care. Multiple studies have indicated that nanomaterials can be used to successfully treat CNS disorders in the case of neurodegeneration. Nanomedicine development for the cure of degenerative and inflammatory diseases of the nervous system is critical. Nanoparticles may act as a drug transporter that can precisely target sick brain sub-regions, boosting therapy success. It is important to develop strategies that can penetrate the blood–brain barrier (BBB) and improve the effectiveness of medications. One of the probable tactics is the use of different nanoscale materials. These nano-based pharmaceuticals offer low toxicity, tailored delivery, high stability, and drug loading capacity. They may also increase therapeutic effectiveness. A few examples of the many different kinds and forms of nanomaterials that have been widely employed to treat neurological diseases include quantum dots, dendrimers, metallic nanoparticles, polymeric nanoparticles, carbon nanotubes, liposomes, and micelles. These unique qualities, including sensitivity, selectivity, and ability to traverse the BBB when employed in nano-sized particles, make these nanoparticles useful for imaging studies and treatment of NDs. Multifunctional nanoparticles carrying pharmacological medications serve two purposes: they improve medication distribution while also enabling cell dynamics imaging and pharmacokinetic study. However, because of the potential for wide-ranging clinical implications, safety concerns persist, limiting any potential for translation. The evidence for using nanotechnology to create drug delivery systems that could pass across the BBB and deliver therapeutic chemicals to CNS was examined in this study.