Revisiting the potential of regulated cell death in glioma treatment: a focus on autophagy-dependent cell death, anoikis, ferroptosis, cuproptosis, pyroptosis, immunogenic cell death, and the crosstalk between them

Gliomas are primary tumors that originate in the central nervous system. The conventional treatment options for gliomas typically encompass surgical resection and temozolomide (TMZ) chemotherapy. However, despite aggressive interventions, the median survival for glioma patients is merely about 14.6 months. Consequently, there is an urgent necessity to explore innovative therapeutic strategies for treating glioma. The foundational study of regulated cell death (RCD) can be traced back to Karl Vogt's seminal observations of cellular demise in toads, which were documented in 1842. In the past decade, the Nomenclature Committee on Cell Death (NCCD) has systematically classified and delineated various forms and mechanisms of cell death, synthesizing morphological, biochemical, and functional characteristics. Cell death primarily manifests in two forms: accidental cell death (ACD), which is caused by external factors such as physical, chemical, or mechanical disruptions; and RCD, a gene-directed intrinsic process that coordinates an orderly cellular demise in response to both physiological and pathological cues. Advancements in our understanding of RCD have shed light on the manipulation of cell death modulation - either through induction or suppression - as a potentially groundbreaking approach in oncology, holding significant promise. However, obstacles persist at the interface of research and clinical application, with significant impediments encountered in translating to therapeutic modalities. It is increasingly apparent that an integrative examination of the molecular underpinnings of cell death is imperative for advancing the field, particularly within the framework of inter-pathway functional synergy. In this review, we provide an overview of various forms of RCD, including autophagy-dependent cell death, anoikis, ferroptosis, cuproptosis, pyroptosis and immunogenic cell death. We summarize the latest advancements in understanding the molecular mechanisms that regulate RCD in glioma and explore the interconnections between different cell death processes. By comprehending these connections and developing targeted strategies, we have the potential to enhance glioma therapy through manipulation of RCD.

Bevacizumab-induced isolated oculomotor nerve palsy in glioblastoma multiforme

INTRODUCTION

Bevacizumab, a monoclonal antibody against the vascular endothelial growth factor receptor, is the standard treatment of recurrent glioblastoma multiforme. In addition to common systemic side effects of bevacizumab, there are rare cases of cranial nerve palsy.

CASE REPORT

We report a case of transient oculomotor nerve palsy after systemic administration of bevacizumab. Twenty-four hours after the systemic infusion of bevacizumab, transient oculomotor nerve palsy developed in a 49-year-old male patient. In the cranial MRI, there was no malignancy-related progression.

MANAGEMENT AND OUTCOME

Bevacizumab treatment was discontinued. Methylprednisolone was started considering that bevacizumab increased the inflammatory response. Oculomotor nerve palsy resolved in 14 days.

DISCUSSION

There are many side effects of bevacizumab whose mechanisms of action have not been fully explained. Cranial nerve involvement is rarely reported. Our case is the first reported case of bevacizumab-induced oculomotor nerve palsy.

Transmembrane Protein TMEM230, a Target of Glioblastoma Therapy

Glioblastomas (GBM) are the most aggressive tumors originating in the brain. Histopathologic features include circuitous, disorganized, and highly permeable blood vessels with intermittent blood flow. These features contribute to the inability to direct therapeutic agents to tumor cells. Known targets for anti-angiogenic therapies provide minimal or no effect in overall survival of 12–15 months following diagnosis. Identification of novel targets therefore remains an important goal for effective treatment of highly vascularized tumors such as GBM. We previously demonstrated in zebrafish that a balanced level of expression of the transmembrane protein TMEM230/C20ORF30 was required to maintain normal blood vessel structural integrity and promote proper vessel network formation. To investigate whether TMEM230 has a role in the pathogenesis of GBM, we analyzed its prognostic value in patient tumor gene expression datasets and performed cell functional analysis. TMEM230 was found necessary for growth of U87-MG cells, a model of human GBM. Downregulation of TMEM230 resulted in loss of U87 migration, substratum adhesion, and re-passaging capacity. Conditioned media from U87 expressing endogenous TMEM230 induced sprouting and tubule-like structure formation of HUVECs. Moreover, TMEM230 promoted vascular mimicry-like behavior of U87 cells. Gene expression analysis of 702 patients identified that TMEM230 expression levels distinguished high from low grade gliomas. Transcriptomic analysis of patients with gliomas revealed molecular pathways consistent with properties observed in U87 cell assays. Within low grade gliomas, elevated TMEM230 expression levels correlated with reduced overall survival independent from tumor subtype. Highest level of TMEM230 correlated with glioblastoma and ATP-dependent microtubule kinesin motor activity, providing a direction for future therapeutic intervention. Our studies support that TMEM230 has both glial tumor and endothelial cell intracellular and extracellular functions. Elevated levels of TMEM230 promote glial tumor cell migration, extracellular scaffold remodeling, and hypervascularization and abnormal formation of blood vessels. Downregulation of TMEM230 expression may inhibit both low grade glioma and glioblastoma tumor progression and promote normalization of abnormally formed blood vessels. TMEM230 therefore is both a promising anticancer and antiangiogenic therapeutic target for inhibiting GBM tumor cells and tumor-driven angiogenesis.

WZY-321, a novel evodiamine analog, inhibits glioma cell growth in an autophagy-associated manner

Glioblastoma is one of the most aggressive types of brain tumor. The median survival rate of patients with glioblastoma (World Health Organization grade IV) is <15 months. Therefore, there is an urgent requirement for the development of novel and efficient therapeutic agents against glioma. In previous studies, WZY-321 (10-hydroxy-1-methyl-8,13b-dihydro-5H,7H-benzo[e]benzofuro[2',3':3,4]pyrido[2,1-b][1,3]oxazin-5-one), a novel evodiamine (Evo) analog, was reported to exhibit enhanced pharmacological properties and improved cytotoxicity against a number of human cancer cell lines compared with Evo. In the current study, the anti-proliferative effect of WZY-321 on SHG-44 and SWO-38 glioma cells was further studied, and its mechanism of action investigated. The results indicated that WZY-321 inhibited the proliferation of SHG-44 cells in a dose- and time-dependent manner by enhancing cellular apoptosis and inducing cell cycle arrest at the G2-M phase. Treatment of glioma cells with WZY-321 concomitantly increased the expression levels of microtubule associated protein 1 light chain 3α and Beclin1, indicating enhanced autophagy. Overall, the results of the present study revealed the anti-proliferative potential of WZY-321 in glioma cells, thus providing a possible autophagy-based therapeutic strategy for the treatment of glioblastoma.

Genetic variants of vascular endothelial growth factor predict risk and survival of gliomas

The vascular endothelial growth factor regulates angiogenesis that is increased in glioma. VEGF polymorphisms are thought to modulate vascular endothelial growth factor plasma levels and therefore may be implicated in glioma risk. We aimed to clarify the role of VEGF and von Willebrand factor polymorphisms in glioma susceptibility and prognosis. A case-control study of 126 glioma patients and 180 cancer-free controls was performed. Using Sequenom MassARRAY platform, 11 VEGF and 1 VWF polymorphisms were genotyped. Unconditional multivariate logistic regression models were used to calculate odds ratios and 95% confidence intervals. The associations between polymorphisms and survival were evaluated using a Cox regression model. Bonferroni's adjustment was used to correct for multiple testing. The VEGF polymorphism rs833061 was strongly associated with increased risk for glioma (odds ratio = 164.85) and glioblastoma (odds ratio = 155.66), confirmed after Bonferroni correction. Also, the VEGF polymorphisms rs3024994, rs2010963, and particularly the homozygous carriers of rs1005230 were associated with a worse prognosis for glioma and glioblastoma. Our data support a role of VEGF and VWF polymorphisms as glioma biomarkers, with additional potential relevance for molecular stratification of patients for anti-angiogenic therapies.

Bevacizumab and gefitinib enhanced whole-brain radiation therapy for brain metastases due to non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC) patients who experience brain metastases are usually associated with poor prognostic outcomes. This retrospective study proposed to assess whether bevacizumab or gefitinib can be used to improve the effectiveness of whole brain radiotherapy (WBRT) in managing patients with brain metastases. A total of 218 NSCLC patients with multiple brain metastases were retrospectively included in this study and were randomly allocated to bevacizumab-gefitinib-WBRT group (n=76), gefitinib-WBRT group (n=77) and WBRT group (n=75). Then, tumor responses were evaluated every 2 months based on Response Evaluation Criteria in Solid Tumors version 1.0. Karnofsky performance status and neurologic examination were documented every 6 months after the treatment. Compared to the standard WBRT, bevacizumab and gefitinib could significantly enhance response rate (RR) and disease control rate (DCR) of WBRT (P<0.001). At the same time, RR and DCR of patients who received bevacizumab-gefitinib-WBRT were higher than those who received gefitinib-WBRT. The overall survival (OS) rates and progression-free survival (PFS) rates also differed significantly among the bevacizumab-gefitinib-WBRT (48.6 and 29.8%), gefitinib-WBRT (36.7 and 29.6%) and WBRT (9.8 and 14.6%) groups (P<0.05). Although bevacizumab-gefitinib-WBRT was slightly more toxic than gefitinib-WBRT, the toxicity was tolerable. As suggested by prolonged PFS and OS status, bevacizumab substantially improved the overall efficacy of WBRT in the management of patients with NSCLC.

Long Non-coding RNA XIST Promotes Glioma Tumorigenicity and Angiogenesis by Acting as a Molecular Sponge of miR-429

Glioma is a worldwide malignancy, which displays significantly active metastasis and angiogenesis. Interaction between long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) has been shown to play crucial role in regulating tumor properties. However, the potential of lncRNA X-inactive specific transcript (XIST) to function as a miRNA regulator and its relevance in glioma tumorigenicity and angiogenesis have so far remained unclear. Expression analysis of lncRNA XIST in glioma cells revealed its significant up-regulation. Interestingly, silencing of XIST repressed both metastatic and pro-angiogenic ability in vitro as well as in vivo. Subsequent studies revealed that lncRNA XIST expression inversely correlated with miR-429 expression in glioma cells; miR-429 modulated XIST expression by directly targeting the XIST gene sequence. In addition, miR-429 inhibitor restored metastatic and pro-angiogenic ability of gliomas abolished by silencing XIST. Our data provide insight into the key roles of the lncRNA-miRNA functional network in gliomas, which can aid in developing new therapeutic strategies for gliomas through clinical trials.

Glioblastoma update: molecular biology, diagnosis, treatment, response assessment, and translational clinical trials

This is an exciting time in neuro-oncology. Discoveries elucidating the molecular mechanisms of oncogenesis and the molecular subtypes of glioblastoma multiforme (GBM) have led to new diagnostic and classification schemes with more prognostic power than histology alone. Molecular profiling has become part of the standard neuropathological evaluation of GBM. Chemoradiation followed by adjuvant temozolomide remains the standard therapy for newly diagnosed GBM, but survival remains unsatisfactory. Patients with recurrent GBM continue to have a dismal prognosis, but neuro-oncology centers with active clinical trial programs are seeing a small but increasing cadre of patients with longer survival. Molecularly targeted therapeutics, personalized therapy based on molecular profiling of individual tumors, and immunotherapeutic strategies are all being evaluated and refined in clinical trials. Understanding of the molecular mechanisms of tumor-mediated immunosuppression, and specifically interactions between tumor cells and immune effector cells in the tumor microenvironment, has led to a new generation of immunotherapies, including vaccine and immunomodulatory strategies as well as T-cell-based treatments. Molecularly targeted therapies, chemoradiation, immunotherapies, and anti-angiogenic therapies have created the need to develop more reliable neuroimaging criteria for differentiating the effects of therapy from tumor progression and changes in blood–brain barrier physiology from treatment response. Translational clinical trials for patients with GBM now incorporate quantitative imaging using both magnetic resonance imaging and positron emission tomography techniques. This update presents a summary of the current standards for therapy for newly diagnosed and recurrent GBM and highlights promising translational research.

Quantification of antiangiogenic treatment effects on tissue heterogeneity in glioma tumour xenograft model using a combination of DCE-MRI and 3D-ultramicroscopy

OBJECTIVES

This study aimed at assessing the effects of an anti-angiogenic treatment, which neutralises vascular endothelial growth factor (VEGF), on tumour heterogeneity.

METHODS

Murine glioma cells have been inoculated into the right brain frontal lobe of 16 mice. Anti-VEGF antibody was administered to a first group (n = 8), while a second group (n = 8) received a placebo. Magnetic resonance acquisitions, performed at days 10, 12, 15 and 23 following the implantation, allowed the derivation of a three-dimensional features dataset characterising tumour heterogeneity. Three-dimensional ultramicroscopy and standard histochemistry analysis have been performed to verify in vivo results.

RESULTS

Placebo-treated mice displayed a highly-vascularised area at the tumour periphery, a monolithic necrotic core and a chaotic dense vasculature across the entire tumour. In contrast, the B20-treated group did not show any highly vascularised regions and presents a fragmented necrotic core. A significant reduction of the number of vessel segments smaller than 17 μm has been observed. There was no difference in overall tumour volume and growth rate between the two groups.

CONCLUSIONS

Region-specific analysis revealed that VEGF inhibition affects only: (1) highly angiogenic compartments expressing high levels of VEGF and characterised by small capillaries, and also (2) the formation and structure of necrotic regions. These effects appear to be transient and limited in time.

KEY POINTS

• VEGF inhibition affects only the highly angiogenic region and small capillaries network • VEGF inhibition is transient in time • Tumour volume is not affected by anti-angiogenic treatment • VEGF inhibition also influences the architecture of necrotic regions.

Increased expression of platelet-derived growth factor associated protein-1 is associated with PDGF-B mediated glioma progression

The current treatment therapies available for malignant gliomas are inadequate. There is an urgent need to develop more effective therapies by characterizing the molecular pathogenesis of the disease. Over expression of platelet-derived growth factor (PDGF) ligands and receptors have been reported in malignant gliomas. Platelet-derived growth factor associated protein-1 (PDAP-1) is reported to modulate the mitogenic activity of PDGF ligands, but to date, there is no information concerning its role in PDGF-mediated glioma cell proliferation. This study aimed to characterize the role of PDAP-1 in PDGF-mediated glioma proliferation. The expression of PDAP-1 was observed to be significantly increased (p<0.05) in grade IV glioma tissue and cell lines compared to grade III. siRNA-mediated knockdown of PDAP-1 reduced the expression of PDGF-B and its downstream genes (Akt1/Protein kinase B (PKB) and phosphoinositide-dependent kinase-1 (PDK1) by up to 50%. In PDAP-1 knockdown glioma cells, more than a twofold reduction was also observed in the level of phosphorylated Akt. Interestingly, knockdown of PDAP-1 in combination with PDGF-B antibody inhibited glioma cell proliferation through activation of Caspase 3/7 and 9. We also demonstrate that PDAP-1 co-localizes with PDGF-B in the cytoplasm of glioma cells, and an interaction between both of the proteins was established. Collectively, these findings suggest that the expression of PDAP-1 is associated with disease malignancy, and its inhibition reduced the proliferation of malignant glioma cells through down-regulation of PDGF-B/Akt/PDK1 signaling. Thus, this study establishes PDAP-1 as an effecter of PDGF signaling in glioma cells and suggests that it could also be a promising therapeutic target.

The extracellular matrix niche microenvironment of neural and cancer stem cells in the brain

Numerous studies demonstrated that neural stem cells and cancer stem cells (NSCs/CSCs) share several overlapping characteristics such as self-renewal, multipotency and a comparable molecular repertoire. In addition to the intrinsic cellular properties, NSCs/CSCs favor a similar environment to acquire and maintain their characteristics. In the present review, we highlight the shared properties of NSCs and CSCs in regard to their extracellular microenvironment called the NSC/CSC niche. Moreover, we point out that extracellular matrix (ECM) molecules and their complementary receptors influence the behavior of NSCs/CSCs as well as brain tumor progression. Here, we focus on the expression profile and functional importance of the ECM glycoprotein tenascin-C, the chondroitin sulfate proteoglycan DSD-1-PG/phosphacan but also on other important glycoprotein/proteoglycan constituents. Within this review, we specifically concentrate on glioblastoma multiforme (GBM). GBM is the most common malignant brain tumor in adults and is associated with poor prognosis despite intense and aggressive surgical and therapeutic treatment. Recent studies indicate that GBM onset is driven by a subpopulation of CSCs that display self-renewal and recapitulate tumor heterogeneity. Based on the CSC hypothesis the cancer arises just from a small subpopulation of self-sustaining cancer cells with the exclusive ability to self-renew and maintain the tumor. Besides the fundamental stem cell properties of self-renewal and multipotency, GBM stem cells share further molecular characteristics with NSCs, which we would like to review in this article.

Saw Palmetto Extract Inhibits Metastasis and Antiangiogenesis through STAT3 Signal Pathway in Glioma Cell

Signal transducer and activator of transcription factor 3 (STAT3) plays an important role in the proliferation and angiogenesis in human glioma. Previous research indicated that saw palmetto extract markedly inhibited the proliferation of human glioma cells through STAT3 signal pathway. But its effect on tumor metastasis and antiangiogenesis is not clear. This study is to further clear the impact of saw palmetto extract on glioma cell metastasis, antiangiogenesis, and its mechanism. TUNEL assay indicated that the apoptotic cells in the saw palmetto treated group are higher than that in the control group (p < 0.05). The apoptosis related protein is detected and the results revealed that saw palmetto extract inhibits the proliferation of human glioma. Meanwhile pSTAT3 is lower in the experimental group and CD34 is also inhibited in the saw palmetto treated group. This means that saw palmetto extract could inhibit the angiogenesis in glioma. We found that saw palmetto extract was an important phytotherapeutic drug against the human glioma through STAT3 signal pathway. Saw palmetto extract may be useful as an adjunctive therapeutic agent for treatment of individuals with glioma and other types of cancer in which STAT3 signaling is activated.

How to train glioma cells to die: molecular challenges in cell death

The five-year survival rate for patients with malignant glioma is less than 10%. Despite aggressive chemo/radiotherapy these tumors have remained resistant to almost every interventional strategy evaluated in patients. Resistance to these agents is attributed to extrinsic mechanisms such as the tumor microenvironment, poor drug penetration, and tumoral heterogeneity. In addition, genetic and molecular examination of these tumors has revealed defective apoptotic regulation, enhanced pro-survival autophagy signaling, and a propensity for necrosis that aids in the adaptation to environmental stress and resistance to treatment. The combination of extrinsic and intrinsic hallmarks in glioma contributes to the multifaceted resistance to traditional anti-tumor agents. Here we describe the biology of the disease relevant to therapeutic resistance, with a specific focus on molecular deregulation of cell death pathways. Emerging studies investigating the targeting of these pathways including BH3 mimetics and autophagy inhibitors that are being evaluated in both the preclinical and clinical settings are discussed. This review highlights the pathways exploited by glioblastoma cells that drive their hallmark pro-survival predisposition and makes therapy development such a challenge.