Glioblastoma: Pathogenesis and Current Status of Chemotherapy and Other Novel Treatments

Glioma-derived exosome Lncrna Agap2-As1 promotes glioma proliferation and metastasis by mediating Tgf-β1 secretion of myeloid-derived suppressor cells

Background

Glioma (GBM) is the most prevalent malignancy worldwide with high morbidity and mortality. Exosome-mediated transfer of long noncoding RNA (lncRNA) has been reported to be associated with human cancers, containing GBM. Meanwhile, myeloid-derived suppressor cells (MDSCs) play a vital role in mediating the immunosuppressive environments in GBM.

Objectives

This study is designed to explore the role and mechanism of exosomal (Exo) lncRNA AGAP2-AS1 on the MDSC pathway in GBM.

Methods

AGAP2-AS1, microRNA-486-3p (miR-486-3p), and Transforming growth factor beta-1 (TGF-β1) levels were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation, apoptosis, migration, and invasion were detected by 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, and Transwell assays. E-cadherin, Vimentin, CD9, CD81, and TGF-β1 protein levels were examined using Western blot. Exosomes were detected by a transmission electron microscope (TEM). Binding between miR-486-3p and AGAP2-AS1 or TGF-β1 was predicted by LncBase or TargetScan and then verified using a dual-luciferase reporter assay.

Results

AGAP2-AS1 was highly expressed in GBM tissues and cells. Functionally, AGAP2-AS1 absence or TGF-β1 knockdown repressed tumor cell growth and metastasis. Furthermore, Exo-AGAP2-AS1 from GBM cells regulated TGF-β1 expression via sponging miR-486-3p in MDSCs. Exo-AGAP2-AS1 upregulation facilitated GBM cell growth and metastasis via the MDSC pathway.

Conclusion

Exo-AGAP2-AS1 boosted GBM cell development partly by regulating the MDSC pathway, hinting at a promising therapeutic target for GBM treatment.

Targeting brain tumors with innovative nanocarriers: bridging the gap through the blood-brain barrier

Background

Glioblastoma multiforme (GBM) is recognized as the most lethal and most highly invasive tumor. The high likelihood of treatment failure arises from the presence of the blood-brain barrier (BBB) and stem cells around GBM, which avert the entry of chemotherapeutic drugs into the tumor mass.

Objective

Recently, several researchers have designed novel nanocarrier systems like liposomes, dendrimers, metallic nanoparticles, nanodiamonds, and nanorobot approaches, allowing drugs to infiltrate the BBB more efficiently, opening up innovative avenues to prevail over therapy problems and radiation therapy.

Methods

Relevant literature for this manuscript has been collected from a comprehensive and systematic search of databases, for example, PubMed, Science Direct, Google Scholar, and others, using specific keyword combinations, including "glioblastoma," "brain tumor," "nanocarriers," and several others.

Conclusion

This review also provides deep insights into recent advancements in nanocarrier-based formulations and technologies for GBM management. Elucidation of various scientific advances in conjunction with encouraging findings concerning the future perspectives and challenges of nanocarriers for effective brain tumor management has also been discussed.

C-Myc/H19/miR-29b axis downregulates nerve/glial (NG)2 expression in glioblastoma multiforme

Nerve/glial antigen (NG)2 is highly expressed in glioblastoma multiforme (GBM). However, the underlying mechanisms of its upregulated expression are largely unknown. In silico analyses reveal that the tumor-suppressive miR-29b targets NG2. We used GBM-based data from The Cancer Genome Atals databases to analyze the expression pattern of miR-29b and different target genes, including NG2. Moreover, we investigated the regulatory function of miR-29b on NG2 expression and NG2-related signaling pathways. We further studied upstream mechanisms affecting miR-29b-dependent NG2 expression. We found that miR-29b downregulates NG2 expression directly and indirectly via the transcription factor Sp1. Furthermore, we identified the NG2 coreceptor platelet-derived growth factor receptor (PDGFR)α as an additional miR-29b target. As shown by a panel of functional cell assays, a reduced miR-29b-dependent NG2 expression suppresses tumor cell proliferation and migration. Signaling pathway analyses revealed that this is associated with a decreased ERK1/2 activity. In addition, we found that the long noncoding RNA H19 and c-Myc act as upstream repressors of miR-29b in GBM cells, resulting in an increased NG2 expression. These findings indicate that the c-Myc/H19/miR-29b axis crucially regulates NG2 expression in GBM and, thus, represents a target for the development of future GBM therapies.

Spatially Resolved Microglia/Macrophages in Recurrent Glioblastomas Overexpress Fatty Acid Metabolism and Phagocytic Genes

BACKGROUND

Glioblastoma (GBM) tumors are rich in tumor-associated microglia/macrophages. Changes associated with treatment in this specific cell population are poorly understood. Therefore, we studied changes in gene expression of tumor-associated microglia/macrophages (Iba1+) cells in de novo versus recurrent GBMs.

METHODS

NanoString GeoMx® Digital Spatial Transcriptomic Profiling of microglia/macrophages (Iba1+) and glial cells (Gfap+) cells identified on tumor sections was performed on paired de novo and recurrent samples obtained from three IDH-wildtype GBM patients. The impact of differentially expressed genes on patient survival was evaluated using publicly available data.

RESULTS

Unsupervised analyses of the NanoString GeoMx® Digital Spatial Profiling data revealed clustering based on the transcriptomic data from Iba1+ and Gfap+ cells. As expected, conventional differential gene expression and enrichment analyses revealed upregulation of immune-function-related genes in Iba1+ cells compared to Gfap+ cells. A focused differential gene expression analysis revealed upregulation of phagocytosis and fatty acid/lipid metabolism genes in Iba1+ cells in recurrent GBM samples compared to de novo GBM samples. Importantly, of these genes, the lipid metabolism gene PLD3 consistently correlated with survival in multiple different publicly available datasets.

CONCLUSION

Tumor-associated microglia/macrophages in recurrent GBM overexpress genes involved in fatty acid/lipid metabolism. Further investigation is needed to fully delineate the role of PLD phospholipases in GBM progression.

Microneedle Patch Delivery of PLCG1-siRNA Efficient Enhanced Temozolomide Therapy for Glioblastoma

The blood-brain barrier (BBB) and drug resistance present challenges for chemotherapy of glioblastoma (GBM). A microneedle (MN) patch with excellent biocompatibility and biodegradability was designed to bypass the BBB and release temozolomide (TMZ) and PLCG1-siRNA directly into the tumor site for synergistic treatment of GBM. The codelivery of TMZ and PLCG1-siRNA enhanced DNA damage and apoptosis. The potential mechanism behind this enhancement is to knockdown of PLCG1 expression, which positively regulates the expression of signal transducer and activator of transcription 3 genes, thereby preventing DNA repair and enhancing the sensitivity of GBM to TMZ. The MN patch enables long-term sustainable drug release through in situ implantation and increases local drug concentrations in diseased areas, significantly extending mouse survival time compared to other drug treatment groups. MN drug delivery provides a platform for the combination treatment of GBM and other central nervous system diseases.

Potential of Nanocarrier-Associated Approaches for Better Therapeutic Intervention in the Management of Glioblastoma

Glioblastoma, commonly known as glioblastoma multiforme (GBM), is one of the deadliest and most invasive types of brain cancer. Two factors account for the majority of the treatment limitations for GBM. First, the presence of the blood-brain barrier (BBB) renders malignancy treatment ineffective, leading to recurrence without full recovery. Second, several adverse effects are associated with the drugs used in conventional GBM treatment. Recent studies have developed nanocarrier systems, such as liposomes, polymeric micelles, dendrimers, nanosuspensions, nanoemulsions, nanostructured lipid carriers, solid lipid nanocarriers, metal particles, and silica nanoparticles, which allow drug-loaded formulations to penetrate the BBB more effectively. This has opened up new possibilities for overcoming therapy issues. Extensive and methodical searches of databases such as PubMed, Science Direct, Google Scholar, and others were conducted to gather relevant literature for this work, using precise keyword combinations such as "GBM," "brain tumor," and "nanocarriers." This review provides deep insights into the administration of drugs using nanocarriers for the management of GBM and explores new advancements in nanotechnology. It also highlights how scientific developments can be explained in connection with hopeful findings about the potential of nanocarriers for the future successful management of GBM.

Development and validation of an LC-MS/MS method for the determination of ARN14988, an acid ceramidase inhibitor, and its application to a pharmacokinetic study in a mouse model

Despite aggressive treatment approaches, the overall survival of glioblastoma (GBM) patients remained poor with a strong need for more effective chemotherapeutic agents. A previous study has shown that ARN14988 is more cytotoxic to GBM cells compared to US Food and Drug Administration-approved temozolomide. This finding makes ARN14988 a desirable candidate for further pharmacological assessment. Therefore, an efficient analytical method is needed to quantify ARN14988. Herein, we have developed and validated sample preparation and LC-MS/MS triple quadrupole (QQQ) method for quantification of ARN14988 in mouse plasma. In this method, the liquid-liquid extraction of ARN14988 from mouse plasma was performed using 5% ethyl acetate in hexane. The chromatographic separation was achieved using a C18 -column with mobile phases of 10 mm ammonium acetate (pH 5) and 0.1% formic acid in methanol, within a runtime of 10 min. The monitored transitions were m/z 391.20 → m/z 147.00 for ARN14988, and m/z 455.30 → m/z 165.00 for verapamil (internal standard) in positive electrospray ionization. The developed method for ARN14988 showed linearity over the range of 10-5,000 ng/ml (r2  > 0.99). The selectivity, sensitivity, matrix effect, recovery, stability, inter-day and intraday accuracy and precision were determined using four quality control samples. This validated method was successfully applied to the pharmacokinetic study of ARN14988 in mice.

Modern Photodynamic Glioblastoma Therapy Using Curcumin- or Parietin-Loaded Lipid Nanoparticles in a CAM Model Study

Natural photosensitizers, such as curcumin or parietin, play a vital role in photodynamic therapy (PDT), causing a light-mediated reaction that kills cancer cells. PDT is a promising treatment option for glioblastoma, especially when combined with nanoscale drug delivery systems. The curcumin- or parietin-loaded lipid nanoparticles were prepared via dual asymmetric centrifugation and subsequently characterized through physicochemical analyses including dynamic light scattering, laser Doppler velocimetry, and atomic force microscopy. The combination of PDT and lipid nanoparticles has been evaluated in vitro regarding uptake, safety, and efficacy. The extensive and well-vascularized chorioallantois membrane (CAM) of fertilized hen's eggs offers an optimal platform for three-dimensional cell culture, which has been used in this study to evaluate the photodynamic efficacy of lipid nanoparticles against glioblastoma cells. In contrast to other animal models, the CAM model lacks a mature immune system in an early stage, facilitating the growth of xenografts without rejection. Treatment of xenografted U87 glioblastoma cells on CAM was performed to assess the effects on tumor viability, growth, and angiogenesis. The xenografts and the surrounding blood vessels were targeted through topical application, and the effects of photodynamic therapy have been confirmed microscopically and via positron emission tomography and X-ray computed tomography. Finally, the excised xenografts embedded in the CAM were analyzed histologically by hematoxylin and eosin and KI67 staining.

Glycation Interferes with the Expression of Sialyltransferases and Leads to Increased Polysialylation in Glioblastoma Cells

Glioblastoma (GBM) is a highly aggressive brain tumor that often utilizes aerobic glycolysis for energy production (Warburg effect), resulting in increased methylglyoxal (MGO) production. MGO, a reactive dicarbonyl compound, causes protein alterations and cellular dysfunction via glycation. In this study, we investigated the effect of glycation on sialylation, a common post-translational modification implicated in cancer. Our experiments using glioma cell lines, human astrocytes (hA), and primary glioma samples revealed different gene expressions of sialyltransferases among cells, highlighting the complexity of the system. Glycation has a differential effect on sialyltransferase expression, upregulating ST8SIA4 in the LN229 and U251 cell lines and decreasing the expression in normal hA. Subsequently, polysialylation increased in the LN229 and U251 cell lines and decreased in hA. This increase in polysialylation could lead to a more aggressive phenotype due to its involvement in cancer hallmark processes such as immune evasion, resistance to apoptosis, and enhancing invasion. Our findings provide insights into the mechanisms underlying GBM aggressiveness and suggest that targeting glycation and sialylation could be a potential therapeutic strategy.

Therapeutic effects against high-grade glioblastoma mediated by engineered induced neural stem cells combined with GD2-specific CAR-NK

PURPOSE

High-grade glioblastoma is extremely challenging to treat because of its aggressiveness and resistance to conventional chemo- and radio-therapies. On the contrary, genetic and cellular immunotherapeutic strategies based on the stem and immune cells are emerging as promising treatments against glioblastoma (GBM). We aimed to developed a novel combined immunotherapeutic strategy to improve the treatment efficacy using genetically engineered PBMC-derived induced neural stem cells (iNSCs) expressing HSV-TK and second-generation CAR-NK cells against GBM.

METHODS

iNSCs cells expressing HSV-TK (iNSCsTK) and GD2-specific CAR-NK92 (GD2NK92) were generated from PBMC-derived iNSCs and NK92 cell lines, respectively. The anti-tumor effect of iNSCsTK and the combinational therapeutics of iNSCsTK and GD2NK92 were evaluated by GBM cell line using in vitro and in vivo experiments.

RESULTS

PBMC-derived iNSCsTK possessed tumor-tropism migration ability in vitro and in vivo, which exhibited considerable anti-tumor activity via bystander effect in the presence of ganciclovir (GCV). iNSCsTK/GCV could slow GBM progression and prolong median survival in tumor-bearing mice. However, the anti-tumor effect was limited to single therapy. Therefore, the combinational therapeutic effect of iNSCsTK/GCV and GD2NK92 against GBM was investigated. This approach displayed a more significant anti-tumor effect in vitro and in xenograft tumor mice.

CONCLUSIONS

PBMC-derived iNSCsTK showed a significant tumor-tropic migration and an effective anti-tumor activity with GCV in vitro and in vivo. In addition, combined with GD2NK92, iNSCsTK therapeutic efficacy improved dramatically to prolong the tumor-bearing animal model's median survival.

A Network Pharmacology Prediction and Molecular Docking-Based Strategy to Explore the Potential Pharmacological Mechanism of Astragalus membranaceus for Glioma

Glioma treatment in traditional Chinese medicine has a lengthy history. Astragalus membranaceus, a traditional Chinese herb that is frequently utilized in therapeutic practice, is a component of many Traditional Chinese Medicine formulas that have been documented to have anti-glioma properties. Uncertainty persists regarding the molecular mechanism behind the therapeutic effects. Based on results from network pharmacology and molecular docking, we thoroughly identified the molecular pathways of Astragalus membranaceus' anti-glioma activities in this study. According to the findings of the enrichment analysis, 14 active compounds and 343 targets were eliminated from the screening process. These targets were mainly found in the pathways in cancer, neuroactive ligand-receptor interaction, protein phosphorylation, inflammatory response, positive regulation of phosphorylation, and inflammatory mediator regulation of Transient Receptor Potential (TRP) channels. The results of molecular docking showed that the active substances isoflavanone and 1,7-Dihydroxy-3,9-dimethoxy pterocarpene have strong binding affinities for the respective targets ESR2 and PTGS2. In accordance with the findings of our investigation, Astragalus membranaceus active compounds exhibit a multicomponent and multitarget synergistic therapeutic impact on glioma by actively targeting several targets in various pathways. Additionally, we propose that 1,7-Dihydroxy-3,9-dimethoxy pterocarpene and isoflavanone may be the main active ingredients in the therapy of glioma.

Novel approaches targeting ferroptosis in treatment of glioma

Glioma is a malignant brain tumor with a high mortality rate; hence novel treatment approaches are being explored to improve patient outcomes. Ferroptosis, a newly described form of regulated cell death, is emerging as a potential therapeutic target in glioma. Ferroptosis is characterized by the accumulation of lipid peroxides due to a loss of intracellular antioxidant systems represented by the depletion of glutathione and decreased activity of glutathione peroxidase 4 (GPX4). Since glioma cells have a high demand for iron and lipid metabolism, modulation of ferroptosis may represent a promising therapeutic approach for this malignancy. Recent studies indicate that ferroptosis inducers like erastin and RSL3 display potent anticancer activity in a glioma model. In addition, therapeutic strategies, including GPX4 targeting, lipid metabolism modulation, inhibition of amino acid transporters, and ferroptosis targeting natural compounds, have shown positive results in preclinical studies. This review will provide an overview of the functions of ferroptosis in glioma and its potential as a suitable target for glioma therapy.

General Clinico-Pathological Characteristics in Glioblastomas in Correlation with p53 and Ki67

Introduction: A glioblastoma is an intra-axial brain tumour of glial origin that belongs to the category of diffuse gliomas and is the most common malignant neoplasia of the central nervous system. The rate of survival at 5 years, from the moment of diagnosis, is not higher than 10%. Materials and methods: In this retrospective study, fifty-four patients diagnosed with glioblastoma, from the Pathology Department of the County Emergency Clinical Hospital of Târgu Mureș, between 2014 and 2017 were included. We studied the clinico-pathological data (age, gender, location, and laterality) and, respectively, the immunoexpression of p53, Ki67, ATRX, and IDH-1 proteins. Results: We observed a statistically significant association between the laterality of the tumour according to the age groups, with the localization on the right side being more frequent in the age group below 65 years of age, while the involvement of the left hemisphere was more prevalent in those over 65 years. Out of the total 54 cases, 87.04% were found to be primary glioblastomas; more than 70% of the cases were ATRX immunopositive; almost 80% of the glioblastomas studied had wild-type p53 profile; and 35% of the cases were found to have a Ki67 index greater than 20%. A statistically significant association between gender and ATRX mutation was found; female cases were ATRX immunopositive in 92% of the cases. Almost 70% of the cases were both IDH-1 and p53 wild-type, and we observed the presence of both mutations in only 3.7% of the cases. Approximately 83% of primary glioblastomas were ATRX positive, respectively, and all IDH-1 mutant cases were ATRX negative. Conclusions: Glioblastomas still represent a multidisciplinary challenge considering their reserved prognosis. In this study, we described the most common clinico-pathological characteristics and IHC marker expression profiles, highlighting a variety of percentage ranges in primary and secondary glioblastomas. Given the small number of studied cases, further prospective studies on larger cohorts are needed in the future to evaluate the role of these immunohistochemical markers as prognostic factors for survival or recurrence.

Mishel's uncertainty in illness theory: Informing nursing diagnoses and care planning

PURPOSE

Patients with glioblastoma multiforme (GBM) face uncertainty during the illness trajectory that decreases their quality of life. Uncertainty manifests as an altered state of mind in patients with GBM and increases the burden of managing their diagnosis. The uncertainty in illness theory (UIT) can be used to guide nursing practice and create care plans to decrease this uncertainty.

DATA SOURCES

The UIT and conceptual model were used to pair diagnoses from NANDA-I Nursing Diagnoses to form care plans for patients with GBM.

METHODS

In a stepwise approach, concepts from the UIT were organized and cross-walked into an integrated theory-driven practice framework to enhance care planning.

CONCLUSIONS

The UIT helps define and identify circumstances of uncertainty in patients experiencing illness, and Nursing Diagnoses provide engagement and outcomes for those uncertainty-based diagnoses. Some examples of the UIT guiding Nursing Diagnoses includes a patient's cognitive level guiding a Nursing Diagnosis care plan of Risk for Acute Confusion. Social Support can guide the care plan of Risk for Loneliness, and appraisal of uncertainty can guide a care plan for Ineffective Individual Coping. Using the UIT to guide theory-driven practice links interventions and outcomes in patients with GBM.

IMPLICATIONS FOR PRACTICE

The UIT can guide NANDA-I Nursing Diagnoses to assist nurses in creating a nursing care plan for nursing engagement to decrease uncertainty and increase the quality of life in patients with GBM. Theory-driven research defines the application of the UIT in GBM and provides foundational knowledge for theory-driven practice to occur.

Tyrphostin A9 attenuates glioblastoma growth by suppressing PYK2/EGFR-ERK signaling pathway

PURPOSE

Glioblastoma (GBM) is a fatal primary brain tumor with extremely poor clinical outcomes. The anticancer efficiency of tyrosine kinase inhibitors (TKIs) has been shown in GBM and other cancer, with limited therapeutic outcomes. In the current study, we aimed to investigate the clinical impact of active proline-rich tyrosine kinase-2 (PYK2) and epidermal growth factor receptor (EGFR) in GBM and evaluate its druggability by a synthetic TKI-Tyrphostin A9 (TYR A9).

METHODS

The expression profile of PYK2 and EGFR in astrocytoma biopsies (n = 48) and GBM cell lines were evaluated through quantitative PCR, western blots, and immunohistochemistry. The clinical association of phospho-PYK2 and EGFR was analyzed with various clinicopathological features and the Kaplan-Meier survival curve. The phospho-PYK2 and EGFR druggability and subsequent anticancer efficacy of TYR A9 was evaluated in GBM cell lines and intracranial C6 glioma model.

RESULTS

Our expression data revealed an increased phospho-PYK2, and EGFR expression aggravates astrocytoma malignancy and is associated with patients' poor survival. The mRNA and protein correlation analysis showed a positive association between phospho-PYK2 and EGFR in GBM tissues. The in-vitro studies demonstrated that TYR A9 reduced GBM cell growth, cell migration, and induced apoptosis by attenuating PYK2/EGFR-ERK signaling. The in-vivo data showed TYR A9 treatment dramatically reduced glioma growth with augmented animal survival by repressing PYK2/EGFR-ERK signaling.

CONCLUSION

Altogether, this study report that increased phospho-PYK2 and EGFR expression in astrocytoma was associated with poor prognosis. The in-vitro and in-vivo evidence underlined translational implication of TYR A9 by suppressing PYK2/EGFR-ERK modulated signaling pathway. The schematic diagram displayed proof of concept of the current study indicating activated PYK2 either through the Ca2+/Calmodulin-dependent protein kinase II (CAMKII) signaling pathway or autophosphorylation at Tyr402 induces association to the SH2 domain of c-Src that leads to c-Src activation. Activated c-Src in turn activates PYK2 at other tyrosine residues that recruit Grb2/SOS complex and trigger ERK½ activation. Besides, PYK2 interaction with c-Src acts as an upstream of EGFR transactivator that can activate the ERK½ signaling pathway, which induces cell proliferation and cell survival by increasing anti-apoptotic proteins or inhibiting pro-apoptotic proteins. TYR A9 treatment attenuate GBM cell proliferation and migration; and induce GBM cell death by inhibiting PYK2 and EGFR-induced ERK activation.

Multiple therapeutic approaches of glioblastoma multiforme: From terminal to therapy

Glioblastoma multiforme (GBM) is an aggressive brain cancer showing poor prognosis. Currently, treatment methods of GBM are limited with adverse outcomes and low survival rate. Thus, advancements in the treatment of GBM are of utmost importance, which can be achieved in recent decades. However, despite aggressive initial treatment, most patients develop recurrent diseases, and the overall survival rate of patients is impossible to achieve. Currently, researchers across the globe target signaling events along with tumor microenvironment (TME) through different drug molecules to inhibit the progression of GBM, but clinically they failed to demonstrate much success. Herein, we discuss the therapeutic targets and signaling cascades along with the role of the organoids model in GBM research. Moreover, we systematically review the traditional and emerging therapeutic strategies in GBM. In addition, we discuss the implications of nanotechnologies, AI, and combinatorial approach to enhance GBM therapeutics.

4-Methylumbelliferone enhances the effects of chemotherapy on both temozolomide-sensitive and resistant glioblastoma cells

Glioblastoma (GBM) is the most frequent malignant primary tumor of the CNS in adults, with a median survival of 14.6 months after diagnosis. The effectiveness of GBM therapies remains poor, highlighting the need for new therapeutic alternatives. In this work, we evaluated the effect of 4-methylumbelliferone (4MU), a coumarin derivative without adverse effects reported, in combination with temozolomide (TMZ) or vincristine (VCR) on U251, LN229, U251-TMZ resistant (U251-R) and LN229-TMZ resistant (LN229-R) human GBM cells. We determined cell proliferation by BrdU incorporation, migration through wound healing assay, metabolic and MMP activity by XTT and zymography assays, respectively, and cell death by PI staining and flow cytometry. 4MU sensitizes GBM cell lines to the effect of TMZ and VCR and inhibits metabolic activity and cell proliferation on U251-R cells. Interestingly, the lowest doses of TMZ enhance U251-R and LN229-R cell proliferation, while 4MU reverts this and even sensitizes both cell lines to TMZ and VCR effects. We showed a marked antitumor effect of 4MU on GBM cells alone and in combination with chemotherapy and proved, for the first time, the effect of 4MU on TMZ-resistant models, demonstrating that 4MU would be a potential therapeutic alternative for improving GBM therapy even on TMZ-refractory patients.

Personalized Treatment of Glioblastoma: Current State and Future Perspective

Glioblastoma (GBM) is the most aggressive glial tumor of the central nervous system. Despite intense scientific efforts, patients diagnosed with GBM and treated with the current standard of care have a median survival of only 15 months. Patients are initially treated by a neurosurgeon with the goal of maximal safe resection of the tumor. Obtaining tissue samples during surgery is indispensable for the diagnosis of GBM. Technological improvements, such as navigation systems and intraoperative monitoring, significantly advanced the possibility of safe gross tumor resection. Usually within six weeks after the surgery, concomitant radiotherapy and chemotherapy with temozolomide are initiated. However, current radiotherapy regimens are based on population-level studies and could also be improved. Implementing artificial intelligence in radiotherapy planning might be used to individualize treatment plans. Furthermore, detailed genetic and molecular markers of the tumor could provide patient-tailored immunochemotherapy. In this article, we review current standard of care and possibilities of personalizing these treatments. Additionally, we discuss novel individualized therapeutic options with encouraging results. Due to inherent heterogeneity of GBM, applying patient-tailored treatment could significantly prolong survival of these patients.

The STAT3-Regulated Autophagy Pathway in Glioblastoma

Glioblastoma (GBM) is the most common primary brain malignancy in adults with a dismal prognosis. Despite advances in genomic analysis and surgical technique and the development of targeted therapeutics, most treatment options are ineffective and mainly palliative. Autophagy is a form of cellular self-digestion with the goal of recycling intracellular components to maintain cell metabolism. Here, we describe some recent findings that suggest GBM tumors are more sensitive to the excessive overactivation of autophagy leading to autophagy-dependent cell death. GBM cancer stem cells (GSCs) are a subset of the GBM tumor population that play critical roles in tumor formation and progression, metastasis, and relapse, and they are inherently resistant to most therapeutic strategies. Evidence suggests that GSCs are able to adapt to a tumor microenvironment of hypoxia, acidosis, and lack of nutrients. These findings have suggested that autophagy may promote and maintain the stem-like state of GSCs as well as their resistance to cancer treatment. However, autophagy is a double-edged sword and may have anti-tumor properties under certain conditions. The role of the STAT3 transcription factor in autophagy is also described. These findings provide the basis for future research aimed at targeting the autophagy-dependent pathway to overcome the inherent therapeutic resistance of GBM in general and to specifically target the highly therapy-resistant GSC population through autophagy regulation.

Identification of a single cell-based signature for predicting prognosis risk and immunotherapy response in patients with glioblastoma

This study constructed a novel gene pair signature based on bulk and single-cell sequencing samples in relative expression order within the samples. The subsequent analysis included glioma samples from Xiangya Hospital. Gene pair signatures possessed a solid ability to predict the prognosis of glioblastoma and pan-cancer. Samples having different malignant biological hallmarks were distinguished by the algorithm, with the high gene pair score group featuring classic copy number variations, oncogenic mutations, and extensive hypomethylation, mediating poor prognosis. The increased gene pair score group with a poorer prognosis demonstrated significant enrichment in tumor and immune-related signaling pathways while presenting immunological diversity. The remarkable infiltration of M2 macrophages in the high gene pair score group was validated by multiplex immunofluorescence, suggesting that combination therapies targeting adaptive and innate immunity may serve as a therapeutic option. Overall, a gene pair signature applicable to predict prognosis hopefully provides a reference to guide clinical practice.

Discrimination of the chemotherapy resistance status of human leukemia and glioblastoma cell lines by MALDI-TOF-MS profiling

Chemotherapy mistreatment is partially due to a lack of rapid and reliable tools to discriminate between sensitive and resistant phenotypes. In many cases, the resistance mechanism is not fully understood, contributing to the diagnostic tools' absence. This work aims to determine the capacity of MALDI-TOF-MS profiling to discriminate between chemotherapy-resistant and sensitive phenotypes in leukemia and glioblastoma cells. A multivariate analysis of two therapy-resistant leukemia cell lines (Ki562 and Kv562) and two TMZ-resistant glioblastoma cell lines (U251-R and LN229-R) and their sensitive counterparts was performed. In this work, we first show MALDI-TOF-MS patterns analysis ability to differentiate these cancer cell lines by their chemotherapy-resistant status. We present a rapid and inexpensive tool that would guide and complement the therapeutic decision.

Interpreting the Therapeutic Efficiency of Multifunctional Hybrid Nanostructure against Glioblastoma

Glioblastoma is considered the most fatal malignant brain tumor that starts from the central nervous system (CNS), where the blood-brain barrier (BBB) remains the biggest challenge for active targeting of drugs in malignant brain tumor. Thereby, we have designed a paclitaxel PTX@ANG/FA-NPs hybrid novel nanodrug delivery system that can overcome the clinical BBB. The structural and morphological characterization of PTX@ANG/FA-NPs confirmed successful synthesis of nanomicelles with the size range of about 160 to 170 nm. The overall repressive effect of PTX@ANG/FA-NPs on human glioblastoma U251 cells was 1.2-times that of PTX alone. In vitro cellular uptake assay also demonstrated that the dual-targeted nanoparticles (NPs) were more easily taken up by glioblastoma U251 cells. Although the antiglioblastoma activity was confirmed by cell migration assay, apoptosis assay, and cellular uptake assay, the absorption was studied by in vivo fluorescence imaging and brain distribution. The synthesized PTX@ANG/FA-NPs probe significantly inhibited the migration of U251 within the cells and promoted the apoptosis process. Moreover, the RhB@ANG/FA-NPs and PTX@ANG/FA-NPs showed higher accumulating potential at sites of tumor BBB disruption. The novel nanodrug delivery system mediated enhanced distribution of drugs at the targeted site for therapeutics efficacies against glioblastomas across the BBB.

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.

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.

Circular RNA circ_0000741/miR-379-5p/TRIM14 signaling axis promotes HDAC inhibitor (SAHA) tolerance in glioblastoma

BACKGROUND

Histone deacetylase (HDAC) inhibitor-based therapeutic drug tolerance is a major obstacle to glioblastoma (GBM) treatment. Meanwhile, non-coding RNAs have been reported to be involved in the regulation of HDAC inhibitor (SAHA) tolerance in some human tumors. However, the relationship between circular RNAs (circRNAs) and SAHA tolerance is still unknown. Herein, we explored the role and mechanism of circ_0000741 on SAHA tolerance in GBM.

METHODS

Circ_0000741, microRNA-379-5p (miR-379-5p), and tripartite motif-containing 14 (TRIM14) level were detected by real-time quantitative polymerase chain reaction (RT-qPCR). (4-5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU), Colony formation, flow cytometry, and transwell assays were used to detect SAHA tolerance, proliferation, apoptosis, and invasion in SAHA-tolerant GBM cells. Western blot analysis of protein levels of E-cadherin, N-cadherin, and TRIM14. After Starbase2.0 analysis, the binding between miR-379-5p and circ_0000741 or TRIM14 was proved using a dual-luciferase reporter. The role of circ_0000741 on drug tolerance was assessed using a xenograft tumor model in vivo.

RESULTS

Circ_0000741 and TRIM14 were upregulated, and miR-379-5p was reduced in SAHA-tolerant GBM cells. Furthermore, circ_0000741 absence reduced SAHA tolerance, suppressed proliferation, invasion, and induced apoptosis in SAHA-tolerant GBM cells. Mechanistically, circ_0000741 might affect TRIM14 content via sponging miR-379-5p. Besides, circ_0000741 silencing enhanced the drug sensitivity of GBM in vivo.

CONCLUSION

Circ_0000741 might accelerate SAHA tolerance by regulating the miR-379-5p/TRIM14 axis, which provided a promising therapeutic target for GBM treatment.

Exploring the Past, Present, and Future of Anti-Angiogenic Therapy in Glioblastoma

Glioblastoma, a WHO grade IV astrocytoma, constitutes approximately half of malignant tumors of the central nervous system. Despite technological advancements and aggressive multimodal treatment, prognosis remains dismal. The highly vascularized nature of glioblastoma enables the tumor cells to grow and invade the surrounding tissue, and vascular endothelial growth factor-A (VEGF-A) is a critical mediator of this process. Therefore, over the past decade, angiogenesis, and more specifically, the VEGF signaling pathway, has emerged as a therapeutic target for glioblastoma therapy. This led to the FDA approval of bevacizumab, a monoclonal antibody designed against VEGF-A, for treatment of recurrent glioblastoma. Despite the promising preclinical data and its theoretical effectiveness, bevacizumab has failed to improve patients' overall survival. Furthermore, several other anti-angiogenic agents that target the VEGF signaling pathway have also not demonstrated survival improvement. This suggests the presence of other compensatory angiogenic signaling pathways that surpass the anti-angiogenic effects of these agents and facilitate vascularization despite ongoing VEGF signaling inhibition. Herein, we review the current state of anti-angiogenic agents, discuss potential mechanisms of anti-angiogenic resistance, and suggest potential avenues to increase the efficacy of this therapeutic approach.

The role of cell membrane-coated nanoparticles as a novel treatment approach in glioblastoma

Glioblastoma multiform (GBM) is the most prevalent and deadliest primary brain malignancy in adults, whose median survival rate does not exceed 15 months after diagnosis. The conventional treatment of GBM, including maximal safe surgery followed by chemotherapy and radiotherapy, usually cannot lead to notable improvements in the disease prognosis and the tumor always recurs. Many GBM characteristics make its treatment challenging. The most important ones are the impermeability of the blood-brain barrier (BBB), preventing chemotherapeutic drugs from reaching in adequate amounts to the tumor site, intratumoral heterogeneity, and roles of glioblastoma stem cells (GSCs). To overcome these barriers, the recently-developed drug-carrying approach using nanoparticles (NPs) may play a significant role. NPs are tiny particles, usually less than 100 nm showing various diagnostic and therapeutic medical applications. In this regard, cell membrane (CM)-coated NPs demonstrated several promising effects in GBM in pre-clinical studies. They benefit from fewer adverse effects due to their specific targeting of tumor cells, biocompatibility because of their CM surfaces, prolonged half-life, easy penetrating of the BBB, and escaping from the immune reaction, making them an attractive option for GBM treatment. To date, CM-coated NPs have been applied to enhance the effectiveness of major therapeutic approaches in GBM treatment, including chemotherapy, immunotherapy, gene therapy, and photo-based therapies. Despite the promising results in pre-clinical studies regarding the effectiveness of CM-coated NPs in GBM, significant barriers like high expenses, complex preparation processes, and unknown long-term effects still hinder its mass production for the clinic. In this regard, the current study aims to provide an overview of different characteristics of CM-coated NPs and comprehensively investigate their application as a novel treatment approach in GBM.

Clinically relevant glioblastoma patient-derived xenograft models to guide drug development and identify molecular signatures

Glioblastoma (GBM) heterogeneity, aggressiveness and infiltrative growth drastically limit success of current standard of care drugs and efficacy of various new therapeutic approaches. There is a need for new therapies and models reflecting the complex biology of these tumors to analyze the molecular mechanisms of tumor formation and resistance, as well as to identify new therapeutic targets. We established and screened a panel of 26 patient-derived subcutaneous (s.c.) xenograft (PDX) GBM models on immunodeficient mice, of which 15 were also established as orthotopic models. Sensitivity toward a drug panel, selected for their different modes of action, was determined. Best treatment responses were observed for standard of care temozolomide, irinotecan and bevacizumab. Matching orthotopic models frequently show reduced sensitivity, as the blood-brain barrier limits crossing of the drugs to the GBM. Molecular characterization of 23 PDX identified all of them as IDH-wt (R132) with frequent mutations in EGFR, TP53, FAT1, and within the PI3K/Akt/mTOR pathway. Their expression profiles resemble proposed molecular GBM subtypes mesenchymal, proneural and classical, with pronounced clustering for gene sets related to angiogenesis and MAPK signaling. Subsequent gene set enrichment analysis identified hallmark gene sets of hypoxia and mTORC1 signaling as enriched in temozolomide resistant PDX. In models sensitive for mTOR inhibitor everolimus, hypoxia-related gene sets reactive oxygen species pathway and angiogenesis were enriched. Our results highlight how our platform of s.c. GBM PDX can reflect the complex, heterogeneous biology of GBM. Combined with transcriptome analyses, it is a valuable tool in identification of molecular signatures correlating with monitored responses. Available matching orthotopic PDX models can be used to assess the impact of the tumor microenvironment and blood-brain barrier on efficacy. Our GBM PDX panel therefore represents a valuable platform for screening regarding molecular markers and pharmacologically active drugs, as well as optimizing delivery of active drugs to the tumor.

Glioblastoma multiforme: Diagnosis, treatment, and invasion

Glioblastoma multiforme (GBM) is an essentially incurable brain tumor, which has been explored for approximately a century. Nowadays, surgical resection, chemotherapy, and radiation therapy are still the standardized therapeutic options. However, due to the intrinsic invasion and metastasis features and the resistance to chemotherapy, the survival rate of glioblastoma patients remains unsatisfactory. To improve the current situation, much more research is needed to provide comprehensive knowledge of GBM. In this review, we summarize the latest updates on GBM treatment and invasion. Firstly, we review the traditional and emerging therapies that have been used for GBM treatment. Given the limited efficiency of these therapies, we further discuss the role of invasion in GBM recurrence and progression, and present current research progress on the mode and mechanisms of GBM invasion.

Screening of predicted synergistic multi-target therapies in glioblastoma identifies new treatment strategies

Background

IDH-wildtype glioblastoma (GBM) is a highly malignant primary brain tumor with a median survival of 15 months after standard of care, which highlights the need for improved therapy. Personalized combination therapy has shown to be successful in many other tumor types and could be beneficial for GBM patients.

Methods

We performed the largest drug combination screen to date in GBM, using a high-throughput effort where we selected 90 drug combinations for their activity onto 25 patient-derived GBM cultures. 43 drug combinations were selected for interaction analysis based on their monotherapy efficacy and were tested in a short-term (3 days) as well as long-term (18 days) assay. Synergy was assessed using dose-equivalence and multiplicative survival metrics.

Results

We observed a consistent synergistic interaction for 15 out of 43 drug combinations on patient-derived GBM cultures. From these combinations, 11 out of 15 drug combinations showed a longitudinal synergistic effect on GBM cultures. The highest synergies were observed in the drug combinations Lapatinib with Thapsigargin and Lapatinib with Obatoclax Mesylate, both targeting epidermal growth factor receptor and affecting the apoptosis pathway. To further elaborate on the apoptosis cascade, we investigated other, more clinically relevant, apoptosis inducers and observed a strong synergistic effect while combining Venetoclax (BCL targeting) and AZD5991 (MCL1 targeting).

Conclusions

Overall, we have identified via a high-throughput drug screening several new treatment strategies for GBM. Moreover, an exceptionally strong synergistic interaction was discovered between kinase targeting and apoptosis induction which is suitable for further clinical evaluation as multi-targeted combination therapy.

Diabetes Mellitus Management in the Context of Cranial Tumors

The study of the relationship between cancer and diabetes mellitus (DM) has been under investigation for many decades. Particularly in the field of neurology and neurosurgery, increasing emphasis has been put on the examination of comorbid DM in patients with cranial tumors. Namely, as the most common and invasive type of malignant adult brain tumor, glioblastoma (GBS) has been the focus of said research. Several mechanisms have been described in the attempt to elucidate the underlying association between DM and GBS, with the metabolic phenomenon known as the Warburg effect and its consequential downstream effects serving as the resounding culprits in recent literature. Since the effect seen in cancers like GBS exploits an upregulated form of aerobic glycolysis, the role of a sequela of DM, known as hyperglycemia, will be investigated. In particular, in the treatment of GBS, surgical resection and subsequent chemotherapy and/or radiotherapy are used in conjunction with corticosteroid therapy, the latter of which has been linked to hyperglycemia. Unsurprisingly, comorbid DM patients are significantly susceptible to this disposition. Further, this fact is reflected in recent literature that demonstrates the impact of hyperglycemia on cancer advancement and patient outcomes in several preclinical and clinical studies. Thus, this review will aim to underline the significance of diabetes and glycemic control via standard-of-care treatments such as metformin administration, as well as to describe emerging treatments such as the signaling modulation of insulin-like growth factor and the employment of the ketogenic diet.

Induction of Ferroptosis in Glioblastoma and Ovarian Cancers by a New Pyrrole Tubulin Assembly Inhibitor

We synthesized new aroyl diheterocyclic pyrrole (ARDHEP) 15 that exhibited the hallmarks of ferroptosis. Compound 15 strongly inhibited U-87 MG, OVCAR-3, and MCF-7 cancer cells, induced an increase of cleaved PARP, but was not toxic for normal human primary T lymphocytes at 0.1 μM. Analysis of the levels of lactoperoxidase, malondialdehyde, lactic acid, total glutathione, and ATP suggested that the in vivo inhibition of cancer cell proliferation by 15 went through stimulation of oxidative stress injury and Fe²⁺ accumulation. Quantitative polymerase chain reaction analysis of the mRNA expression in U-87 MG and SKOV-3 tumor tissues from 15-treated mice showed the presence of Ptgs2/Nfe2l2/Sat1/Akr1c1/Gpx4 genes correlated with ferroptosis in both groups. Immunofluorescence staining revealed significantly lower expressions of proteins Ki67, CD31, and ferroptosis negative regulation proteins glutathione peroxidase 4 (GPX4) and FTH1. Compound 15 was found to be metabolically stable when incubated with human liver microsomes.

Carbon-ion radiotherapy boost with standard dose proton radiation for incomplete-resected high-grade glioma: a phase 1 study

Background

To investigate the maximal tolerated dose (MTD) of a carbon-ion radiotherapy (CIRT) boost prior to standard dose proton radiotherapy (PRT) for newly diagnosed glioblastoma (GBM) and anaplastic astrocytoma (AA) patients with residual lesion after resection.

Methods

In total, 18 patients with high-grade glioma (HGG) (16 with GBM and 2 with AA) were enrolled in a prospective 3×3 design phase 1 trial. We investigated four dose-levels of CIRT boost [9 (starting level), 12, 15, and 18 Gy relative biological effectiveness (RBE)] delivered in three equal fractions prior to the standard dose PRT (60 Gy RBE in 30 fractions). Concurrent temozolomide (TMZ) was not provided during the CIRT boost but was initiated on the first day of PRT. Acute and late toxicities were scored based on the Common Terminology Criteria for Adverse Events (CTCAE, v 4.03). Dose-limiting toxicities (DLTs) were defined as radiation-induced severe toxicities (≥ grade 3).

Results

With a median follow-up of 17.9 months, no severe (≥ grade 3) acute or late toxicities were observed in patients treated with the first three dose levels (CIRT boost doses of 9, 12, 15 Gy RBE). Severe late toxicity (grade 3 radiation necrosis) was observed in the first patient treated with the 18 Gy RBE CIRT boost level. Therefore, this trial was terminated and the MTD of the induction CIRT boost was determined at 15 Gy RBE in 3 fractions. At the time of this analysis, both patients with AA were alive without disease progression. The progression-free survival (PFS) and overall survival (OS) for GBM at 12 months were 50.6% and 78.6%, respectively.

Conclusions

Particle beam radiotherapy consisting of a CIRT boost of 15 Gy RBE (in 3 fractions) following standard dose PRT (60 Gy RBE in 30 fractions), and used in conjunction with TMZ, is safe and potentially effective for patients with HGG.

Recent Advances in Glioma Cancer Treatment: Conventional and Epigenetic Realms

Glioblastoma (GBM) is the most typical and aggressive form of primary brain tumor in adults, with a poor prognosis. Successful glioma treatment is hampered by ineffective medication distribution across the blood-brain barrier (BBB) and the emergence of drug resistance. Although a few FDA-approved multimodal treatments are available for glioblastoma, most patients still have poor prognoses. Targeting epigenetic variables, immunotherapy, gene therapy, and different vaccine- and peptide-based treatments are some innovative approaches to improve anti-glioma treatment efficacy. Following the identification of lymphatics in the central nervous system, immunotherapy offers a potential method with the potency to permeate the blood-brain barrier. This review will discuss the rationale, tactics, benefits, and drawbacks of current glioma therapy options in clinical and preclinical investigations.

Eltanexor Effectively Reduces Viability of Glioblastoma and Glioblastoma Stem-Like Cells at Nano-Molar Concentrations and Sensitizes to Radiotherapy and Temozolomide

Current standard adjuvant therapy of glioblastoma multiforme (GBM) using temozolomide (TMZ) frequently fails due to therapy resistance. Thus, novel therapeutic approaches are highly demanded. We tested the therapeutic efficacy of the second-generation XPO1 inhibitor Eltanexor using assays for cell viability and apoptosis in GBM cell lines and GBM stem-like cells. For most GBM-derived cells, IC₅₀ concentrations for Eltanexor were below 100 nM. In correlation with reduced cell viability, apoptosis rates were significantly increased. GBM stem-like cells presented a combinatorial effect of Eltanexor with TMZ on cell viability. Furthermore, pretreatment of GBM cell lines with Eltanexor significantly enhanced radiosensitivity in vitro. To explore the mechanism of apoptosis induction by Eltanexor, TP53-dependent genes were analyzed at the mRNA and protein level. Eltanexor caused induction of TP53-related genes, TP53i3, PUMA, CDKN1A, and PML on both mRNA and protein level. Immunofluorescence of GBM cell lines treated with Eltanexor revealed a strong accumulation of CDKN1A, and, to a lesser extent, of p53 and Tp53i3 in cell nuclei as a plausible mechanism for Eltanexor-induced apoptosis. From these data, we conclude that monotherapy with Eltanexor effectively induces apoptosis in GBM cells and can be combined with current adjuvant therapies to provide a more effective therapy of GBM.

Design, Synthesis and Activity of New N1-Alkyl Tryptophan Functionalized Dendrimeric Peptides against Glioblastoma

Background: Due to resistance to conventional therapy, a blood–brain barrier that results in poor drug delivery, and a high potential for metastasis, glioblastoma (GBM) presents a great medical challenge. Since the repertoire of the possible therapies is very limited, novel therapeutic strategies require new drugs as well as new approaches. The multiple roles played by L-tryptophan (Trp) in tumorigenesis of GBM and the previously found antiproliferative properties of Trp-bearing dendrimers against this malignancy prompted us to design novel polyfunctional peptide-based dendrimers covalently attached to N¹-alkyl tryptophan (Trp) residues. Their antiproliferative properties against GBM and normal human astrocytes (NHA) and their antioxidant potential were tested. Methods: Two groups of amphiphilic peptide dendrimers terminated with N¹-butyl and N¹-aminopentane tryptophan were designed. The influence of dendrimers on viability of NHA and human GBM cell lines, displaying different genetic backgrounds and tumorigenic potentials, was determined by the MTT test. The influence of compounds on the clonogenic potential of GBM cells was assessed by colony-formation assay. Dendrimers were tested for radical scavenging potency as well as redox capability (DPPH, ABTS, and FRAP models). Results: Several peptide dendrimers functionalized with N¹-alkyl-tryptophan at 5 µM concentration exhibited high selectivity towards GBM cells retaining 85–95% viable NHA cells while killing cancer cells. In both the MTT and colony-formation assays, compounds 21 (functionalized with N¹-butyl-Trp and (+)8 charged) and 25 (functionalized with N¹-aminopentane-Trp and (+)12 charged) showed the most promise for their development into anticancer drugs. According to ABTS, DPPH, and FRAP antioxidant tests, dendrimers functionalized with N¹-alkylated Trp expressed higher ROS-scavenging capacity (ABTS and DPPH) than those with unsubstituted Trp. Conclusions: Peptide dendrimers functionalized with N¹-alkyl-tryptophan showed varying toxicity to NHA, while all were toxic to GBM cells. Based on their activity towards inhibition of GBM viability and relatively mild effect on NHA cells the most advantageous were derivatives 21 and 25 with the respective di-dodecyl and dodecyl residue located at the C-terminus. As expected, peptide dendrimers functionalized with N¹-alkyl-tryptophan expressed higher scavenging potency against ROS than dendrimers with unsubstituted tryptophan.

Challenges and Opportunities for Immunoprofiling Using a Spatial High-Plex Technology: The NanoString GeoMx® Digital Spatial Profiler

Characterization of the tumor microenvironment through immunoprofiling has become an essential resource for the understanding of the complex immune cell interactions and the assessment of biomarkers for prognosis and prediction of immunotherapy response; however, these studies are often limited by tissue heterogeneity and sample size. The nanoString GeoMx^® Digital Spatial Profiler (DSP) is a platform that allows high-plex profiling at the protein and RNA level, providing spatial and temporal assessment of tumors in frozen or formalin-fixed paraffin-embedded limited tissue sample. Recently, high-impact studies have shown the feasibility of using this technology to identify biomarkers in different settings, including predictive biomarkers for immunotherapy in different tumor types. These studies showed that compared to other multiplex and high-plex platforms, the DSP can interrogate a higher number of biomarkers with higher throughput; however, it does not provide single-cell resolution, including co-expression of biomarker or spatial information at the single-cell level. In this review, we will describe the technical overview of the platform, present current evidence of the advantages and limitations of the applications of this technology, and provide important considerations for the experimental design for translational immune-oncology research using this tissue-based high-plex profiling approach.

Biomarkers Regulated by Lipid-Soluble Vitamins in Glioblastoma

Glioblastoma (GBM), a highly lethal form of adult malignant gliomas with little clinical advancement, raises the need for alternative therapeutic approaches. Lipid-soluble vitamins have gained attention in malignant brain tumors owing to their pleiotropic properties and their anti-cancer potential have been reported in a number of human GBM cell lines. The aim of this paper is to systematically review and describe the roles of various biomarkers regulated by lipid-soluble vitamins, such as vitamins A, D, E, and K, in the pathophysiology of GBM. Briefly, research articles published between 2005 and 2021 were systematically searched and selected from five databases (Scopus, PubMed, Ovid MEDLINE, EMBASE via Ovid, and Web of Science) based on the study’s inclusion and exclusion criteria. In addition, a number of hand-searched research articles identified from Google Scholar were also included for the analysis. A total of 40 differentially expressed biomarkers were identified from the 19 eligible studies. The results from the analysis suggest that retinoids activate cell differentiation and suppress the biomarkers responsible for stemness in human GBM cells. Vitamin D appears to preferentially modulate several cell cycle biomarkers, while vitamin E derivatives seem to predominantly modulate biomarkers related to apoptosis. However, vitamin K1 did not appear to induce any significant changes to the Raf/MEK/ERK signaling or apoptotic pathways in human GBM cell lines. From the systematic analysis, 12 biomarkers were identified that may be of interest for further studies, as these were modulated by one or two of these lipid-soluble vitamins.

Graphene Oxide Nanoplatforms to Enhance Cisplatin-Based Drug Delivery in Anticancer Therapy

Chemotherapeutics such as platinum-based drugs are commonly used to treat several cancer types, but unfortunately, their use is limited by several side effects, such as high degradation of the drug before entering the cells, off-target organ toxicity and development of drug resistance. An interesting strategy to overcome such limitations is the development of nanocarriers that could enhance cellular accumulation in target cells in addition to decreasing associated drug toxicity in normal cells. Here, we aim to prepare and characterize a graphene-oxide-based 2D nanoplatform functionalised using highly branched, eight-arm polyethylene-glycol, which, owing to its high number of available functional groups, offers considerable loading capacity over its linear modalities and represents a highly potent nanodelivery platform as a versatile system in cancer therapy. The obtained results show that the GO@PEG carrier allows for the use of lower amounts of Pt drug compared to a Pt-free complex while achieving similar effects. The nanoplatform accomplishes very good cellular proliferation inhibition in osteosarcoma, which is strictly related to increased cellular uptake. This enhanced cellular internalization is also observed in glioblastoma, although it is less pronounced due to differences in metabolism compared to osteosarcoma. The proposed GO@PEG nanoplatform is also promising for the inhibition of migration, especially in highly invasive breast carcinoma (i.e., MDA-MB-231 cell line), neutralizing the metastatic process. The GO@PEG nanoplatform thus represents an interesting tool in cancer treatment that can be specifically tailored to target different cancers.

RNF216 Alleviates Radiation-Induced Apoptosis and DNA Damage Through Regulating Ubiquitination-Mediated Degradation of p53 in Glioblastoma

Glioblastoma (GBM) is the most common and lethal subtype of glioma, characterized by uncontrolled cancer cell proliferation, extensive infiltration, and therapeutic resistance. Ring finger protein 216 (RNF216) is a RING-type E3 ubiquitin ligase aberrantly expressed in multiple human cancers. Tumor protein 53 (p53) is a transcription factor that acts as a tumor suppressor. This study aimed to compare the RNF216 expression in GBM tissues and normal peritumoral tissues and to examine the effects of RNF216 overexpression/knockdown on tumorigenesis, radioresistance, and the p53 pathway in GBM. The results showed that RNF216 was overexpressed in GBM tissues and cell lines, and high RNF216 expression was related to a poor prognosis. RNF216 overexpression promoted GBM cell growth and inhibited apoptosis, while RNF216 knockdown impaired GBM cell growth and enhanced cell death. RNF216 was also highly expressed in recurrent GBM tissues compared with paired primary tumors. The upregulation of RNF216 not only facilitated GBM cell growth but also protected cells against X-ray irradiation-induced apoptosis and DNA damage, while RNF216 knockdown exerted opposite effects. Moreover, the implantation of GBM cells with RNF216 silencing suppressed tumorigenesis and increased radiosensitivity of mice bearing GBM xenografts. Further analysis revealed that RNF216 overexpression reduced the stability of p53 protein via ubiquitination and negatively regulated the p53 pathway, while RNF216 knockdown preserved the p53 protein. In conclusion, RNF216 effectively attenuated radiation-induced apoptosis and DNA damage in GBM via inducing ubiquitination-mediated degradation of p53. These findings suggest the potential therapeutic use of RNF216 inhibition for tumorigenesis and therapeutic resistance in GBM.

Ultrasmall Nanoparticle Delivery of Doxorubicin Improves Therapeutic Index for High-Grade Glioma

Purpose: Despite dramatic growth in the number of small molecule drugs developed to treat solid tumors, durable therapeutic options to control primary central nervous system malignancies are relatively scarce. Chemotherapeutic agents which appear biologically potent in model systems have often been found to be marginally effective at best when given systemically in clinical trials. This work presents for the first time an ultrasmall (< 8 nm) multimodal core-shell silica nanoparticle, Cornell prime dots (or C' dots), for the efficacious treatment of high-grade gliomas. Experimental Design: This work presents first-in-kind renally-clearable ultrasmall (< 8 nm) multimodal Cornell prime dots (or C' dots) with surface-conjugated doxorubicin via pH-sensitive linkers for the efficacious treatment in two different clinically relevant high-grade glioma models. Results: Optimal drug-per-particle ratios of as-developed nanoparticle-drug conjugates were established and used to obtain favorable pharmacokinetic profiles. The in vivo efficacy results showed significantly improved biological, therapeutic, and toxicological properties over the native drug after intravenous administration in platelet-derived growth factor-driven genetically engineered mouse model, and an epidermal growth factor expressing patient-derived xenograft (EGFR PDX) model. Conclusions: Ultrasmall C' dot-drug conjugates showed great translational potential over doxorubicin for improving the therapeutic outcome of patients with high-grade gliomas, even without a cancer-targeting moiety.

Simultaneous determination of LY3214996, abemaciclib, and M2 and M20 metabolites in human plasma, cerebrospinal fluid, and brain tumor by LC-MS/MS

A sensitive and rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method was established for the quantification of total and unbound concentrations of LY3214996, an extracellular signal-regulated kinase inhibitor; abemaciclib, a cyclin-dependent kinase 4/6 inhibitor; and abemaciclib active metabolites, M2 and M20, in human plasma, brain tumor, and cerebrospinal fluid samples. The method was validated over a concentration range of 0.2–500 nM within a total run time of 3.8 min using isocratic elution on a Kinetex™ F₅ column. Detection was performed on a Sciex QTRAP 6500+ mass spectrometer employing multiple reaction monitoring mode under positive electrospray ionization. The intra- and inter-batch accuracy as well as the precision of the method for all matrices was within ±20% and ≤20% at the lower limit of quantification, and within ±15% and ≤15% for other quality control levels for all analytes. The unbound fractions of drugs and metabolites in spiked and patient samples were determined using an optimized equilibrium dialysis. The validated method was successfully applied in a phase 0/2 clinical trial to assess the central nervous system penetration of LY3214996 and abemaciclib.

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The LC-MS/MS method was validated to measure LY3214996, abemaciclib, M2 and M20 in human plasma, brain tumor, and CSF.

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Unbound fractions of LY3214996, abemaciclib, M2 and M20 were established in human plasma, brain, and brain tumor.

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The total and unbound levels of LY3214996, abemaciclib, M2 and M20 in glioblastoma patients have been reported.

Controlled microwave-assisted reactions: A facile synthesis of polyfunctionally substituted phthalazines as dual EGFR and PI3K inhibitors in CNS SNB-75 cell line

Brain tumors are stubborn cancers with poor prognosis and disappointing survival rates. Targeted cancer therapeutics with higher efficacy and lower resistance are highly demanded. An efficient one-pot synthesis of polyfunctionalized phthalazines derivatives was developed by reacting ethyl 1-aryl-5-cyano-1,6-dihydro-4-methyl-6-oxo-3-pyridazine-carboxylates with cinnamonitrile derivatives and the cycloaddition reaction of thieno[3,4-d]pyridazines with activated double or triple bond systems under controlled microwave heating with high yields. The resultant synthesized phthalazines (5a-e, 9 and 13) were tested for their in vitro anti-cancer activities by using in vitro one dose assay at National Cancer institute, USA. Only phthalazine (5b) showed broad spectrum anti-tumor activity against most tested cancer cell lines from all subpanels with mean % GI = 22.61. Interestingly, all tested compounds showed varying growth inhibitory activity against a particular cell line, CNS SNB-75 cell line, but (5b) exhibited the highest growth inhibitory activity against CNS-SNB-75 cell line with (GI% = 108.81) and (IC₅₀ = 3.703 ± 0.2) compared to erlotinib; (IC₅₀ = 12.5 ± 0.68). It caused Pre-G1 apoptosis and growth arrest at S phase. It also increased percentage of the total apoptotic cells in CNS-SNB-75 cell line (39.26%) compared to control cells (2.17%) in the annexin V-FITC experiment. It revealed pronounced EGFR inhibitory activity (IC₅₀ = 47.27 ± 2.41 ng/mL) compared to erlotinib (IC₅₀ = 30.7 ± 1.56 ng/mL). It also inhibited the different PI3K isoforms α, β, γ and δ (with IC₅₀ of 4.39, 13.6, 12.5 and 3.11 μg/mL, respectively compared to LY294002 (with IC₅₀ of 12.7, 8.57, 6.89 and 5.7 μg/mL, respectively). It also caused significant lower protein expression levels of pPI3K, AKT, pAKT and Bcl2 and higher protein expression levels of BAX, Casp3 and Casp9 when compared to untreated cells. Conclusion: Phthalazine (5b) may be an effective, convenient and safe anti-cancer agent acting via proapoptotic and dual EGFR and PI3K kinase inhibitory actions in CNS SNB-75 cell line.

The Combined Use of 5-ALA and Chlorin e6 Photosensitizers for Fluorescence-Guided Resection and Photodynamic Therapy under Neurophysiological Control for Recurrent Glioblastoma in the Functional Motor Area after Ineffective Use of 5-ALA: Preliminary Results

The treatment of glial brain tumors is an unresolved problem in neurooncology, and all existing methods (tumor resection, chemotherapy, radiotherapy, radiosurgery, fluorescence diagnostics, photodynamic therapy, etc.) are directed toward increasing progression-free survival for patients. Fluorescence diagnostics and photodynamic therapy are promising methods for achieving gross total resection and additional treatment of residual parts of the tumor. However, sometimes the use of one photosensitizer for photodynamic therapy does not help, and the time until tumor relapse barely increases. This translational case report describes the preliminary results of the first combined use of 5-ALA and chlorin e6 photosensitizers for fluorescence-guided resection and photodynamic therapy of glioblastoma, which allowed us to perform total resection of tumor tissue according to magnetic resonance and computed tomography images, remove additional tissue with increased fluorescence intensity without neurophysiological consequences, and perform additional therapy. Two months after surgery, no recurrent tumor and no contrast uptake in the tumor bed were detected. Additionally, the patient had ischemic changes in the access zone and along the periphery and cystic-glial changes in the left parietal lobe.

Translational Regulation by hnRNP H/F Is Essential for the Proliferation and Survival of Glioblastoma

Deregulation of mRNA translation is a widespread characteristic of glioblastoma (GBM), aggressive malignant brain tumors that are resistant to conventional therapies. RNA-binding proteins (RBPs) play a critical role in translational regulation, yet the mechanisms and impact of these regulations on cancer development, progression and response to therapy remain to be fully understood. Here, we showed that hnRNP H/F RBPs are potent regulators of translation through several mechanisms that converge to modulate the expression and/or the activity of translation initiation factors. Among these, hnRNP H/F regulate the phosphorylation of eIF4E and its translational targets by controlling RNA splicing of the A-Raf kinase mRNA, which in turn modulates the MEK-ERK/MAPK signaling pathway. The underlying mechanism involves RNA G-quadruplex (RG4s), RNA structures whose modulation phenocopies hnRNP H/F translation regulation in GBM cells. Our results highlighted that hnRNP H/F are essential for key functional pathways regulating proliferation and survival of GBM, highlighting its targeting as a promising strategy for improving therapeutic outcomes.

POLE2 facilitates the malignant phenotypes of glioblastoma through promoting AURKA-mediated stabilization of FOXM1

Glioblastoma (GBM) is a type of brain cancer with high morbidity and mortality worldwide. The clinical significance, biological roles, and underlying molecular mechanisms of DNA poly ε-B subunit (POLE2) in GBM were investigated in the study. Firstly, the Cancer Genome Atlas (TCGA) database found that POLE2 was highly expressed in GBM. Immunohistochemistry (IHC) results further confirmed that POLE2 was abnormally elevated in GBM. In addition, loss-of-function assays revealed that POLE2 knockdown could inhibit the malignant behaviors of GBM, especially reduce cell viability, weaken cell clone formation, enhance the sensitivity of apoptosis, restrain migration and inhibit epithelial-mesenchymal transition (EMT) in vitro. In vivo experiments further clarified the suppressive effects of reduced POLE2 expression on tumors. Mechanically, POLE2 knockdown promoted the ubiquitination as well as reduced the stability of Forkhead transcription factor (FOXM1), which is a known tumor promotor in GBM, through Aurora kinase A (AURKA). Moreover, the knockdown of FOXM1 could weaken the promoting effects of POLE2 on malignant behaviors of GBM. In conclusion, our study revealed crucial roles and a novel mechanism of POLE2 involved in GBM through AURKA-mediated stability of FOXM1 and may provide the theoretical basis of molecular therapy for GBM.

Inhibition of Carbonic Anhydrase 2 Overcomes Temozolomide Resistance in Glioblastoma Cells

About 95% of Glioblastoma (GBM) patients experience tumor relapse as a consequence of resistance to the first-line standard chemotherapy using temozolomide (TMZ). Recent studies reported consistently elevated expression levels of carbonic anhydrase CA2 in recurrent glioblastoma and temozolomide-resistant glioblastoma stem-like cells (GSCs). Here we show that CA2 is preferentially expressed in GSCs and upregulated by TMZ treatment. When expressed in GBM cell lines, CA2 exerts significant metabolic changes reflected by enhanced oxygen consumption and increased extracellular acidification causing higher rates of cell invasion. Notably, GBM cells expressing CA2 respond to combined treatment with TMZ and brinzolamide (BRZ), a non-toxic and potent CA2 inhibitor. Interestingly, brinzolamide was more effective than the pan-CA inhibitor Acetazolamide (ACZ) to sensitize naïve GSCs and TMZ-resistant GSCs to TMZ induced cell death. Mechanistically, we demonstrated that the combined treatment of GBM stem cells with TMZ and BRZ caused autophagy of GBM cell lines and GSCs, reflected by enhanced LC3 cleavage (LC3-II) and p62 reduction. Our findings illustrate the potential of CA2 as a chemo-sensitizing drug target in recurrent GBM and propose a combined treatment of TMZ with CA2 inhibitor to tackle GBM chemoresistance and recurrence.