Challenging Hurdles of Current Targeting in Glioblastoma: A Focus on Immunotherapeutic Strategies

Nanoengineered immune check point inhibitors delivery for targeted brain cancer treatment: Current status and future perspectives

Brain tumors create special difficulties because of their position and the protective covering of blood brain barrier (BBB) that restricts efficient medication access. Treatment alternatives such as surgery and chemotherapy demonstrate poor performance against severe brain tumors. The use of immune checkpoint inhibitors (ICIs) hints at effective cancer therapy; however, their application to brain cancer faces challenges due to inefficient delivery through the BBB and the tumor's suppressive environment. Nanoengineering can increase the transport of ICIs to brain tumors. Numerous nano-delivery systems such as liposomes and micelles have explored ways to avoid the BBB via transcytosis and the EPR mechanism. Functionalization of nanocarriers enhances targeting tumor cells and improves treatment accuracy. New developments involve delivering ICIs together with adjuvants to change the TME and focusing on immune cells such as TAMs and Tregs to boost immunity against tumors. Nanoengineered ICIs have shown effective improvement in animal models by reducing toxicity and enhancing efficacy. Converting these successes into real clinical trials is not easy as they face regulatory concerns and safety challenges. Clinical trials currently examine the use of nanocarriers for treating brain cancer; however, scalability' and 'long-term safety' continue to pose challenges. Future approaches will focus on combining customized medicine with advanced nanotechnology and AI to refine treatment methods. Despite obstacles ahead, nanotechnology-based ICIs offer a hopeful approach to enhance brain cancer efficacy and address existing therapeutic constraints.

Glioblastoma therapy: State of the field and future prospects

Glioblastoma (GB) is a cancerous brain tumor that originates from glial cells and leads to thousands of deaths each year and a five-year survival of only 6.8 %. Treatments for GB include surgery, chemotherapy, radiation, and immunotherapy. GB is an incurable fatal disease, necessitating the development of innovative strategies to find a developing effective therapy. Genetic therapies may be crucial in treating GB by identifying the mutations and amplifications of multiple genes, which drive its proliferation and spread. Use of small interfering RNAs (siRNAs) provides a novel technology used to suppress the genes associated with disease, which forms a basis for targeted therapy in GB and its stem cell population, which are recognized for their ability to develop resistance to chemotherapy and tumorigenic capabilities. This review examines the use of siRNAs in GB, emphasizing their effectiveness in suppressing key oncogenes and signaling pathways associated with tumor development, invasion, stemness, and resistance to standard treatments. siRNA-based gene silencing is a promising approach for developing targeted therapeutics against GB and associated stem cell populations, potentially enhancing patient outcomes and survival rates in this devastating disease.

Exploring the combined anti-cancer effects of sodium butyrate and celastrol in glioblastoma cell lines: a novel therapeutic approach

Glioblastoma, a highly aggressive and lethal brain cancer, lacks effective treatment options and has a poor prognosis. In our study, we explored the potential anti-cancer effects of sodium butyrate (SB) and celastrol (CEL) in two glioblastoma cell lines. SB, a histone deacetylase inhibitor, and CEL, derived from the tripterygium wilfordii plant, act as mTOR and proteasome inhibitors. Both can cross the blood-brain barrier, and they exhibit chemo- and radiosensitive properties in various cancer models. GB cell lines LN-405 and T98G were treated with SB and CEL. Cell viability was assessed by MTT assay and IC50 values were obtained. Gene expression of DNA repair, apoptosis, and autophagy-related genes was analyzed by RT-PCR. Cell cycle distribution was determined using flow cytometry. Viability assays using MTT assay revealed IC50 values of 26 mM and 22.7 mM for SB and 6.77 μM, and 9.11 μM for CEL in LN-405 and T98G cells, respectively. Furthermore, we examined the expression levels of DNA repair genes (MGMT, MLH-1, MSH-2, MSH-6), apoptosis genes (caspase-3, caspase-8, caspase-9), and an autophagy gene (ATG-6) using real-time polymerase chain reaction. Additionally, flow cytometry analysis revealed alterations in cell cycle distribution following treatment with SB, CEL and their combination. These findings indicate that SB and CEL may act through multiple mechanisms, including DNA repair inhibition, apoptosis induction, and autophagy modulation, to exert their anti-cancer effects in glioblastoma cells. This is the first study providing novel insights into the potential therapeutic effects of SB and CEL in glioblastoma.

Autologous tumor lysate-loaded dendritic cell vaccination in glioblastoma: What happened to the evidence?

In patients with glioblastoma, the "DCVax-L" trial reported a survival benefit with the addition of autologous tumor lysate-loaded denditric cell vaccination to the standard-of-care (SoC) in patients with glioblastoma. The trial presented as a phase 3 externally controlled trial is showing an improvement in overall survival (OS) in patients receiving the vaccine therapy as compared to externally controlled patients, both in the newly diagnosed setting (median OS = 19.3 months versus 16.5 months; HR = 0.80; 98% CI, 0.00-0.94; P = 0.002) and in the recurrent setting (median OS = 13.2 months versus 7.8 months; HR = 0.58; 98% CI, 0.00-0.76; P < 0.001). Interestingly, the original endpoint, progression-free survival (PFS), was not improved by the experimental therapy. While we praise efforts to improve outcomes in a population representing a true unmet need, the trial's design, methods and report raise several issues undermining the ability to derive meaningful conclusion. These limitations are mainly driven by multiple changes occurring years after the trial ended. External controls were used in a trial originally randomizing patients, the primary endpoint was modified (OS instead of PFS), a new study population (recurrent glioblastoma) was added, and unplanned analyses were conducted, among several other changes. Additionally, due to inclusion criteria, the external controls likely selected patients with less favorable outcome as compared with patients enrolled in the trial, potentially biasing the reported survival benefit. In the absence of data sharing, these shortcomings will not be clarified. Dendritic cell vaccination remains a promising approach for GBM. It is therefore disappointing that due to key methodological limitations, the DCVax-L trial ultimately failed to provide sound conclusions about the potential efficacy of such approach for patients with glioblastoma.

Dendritic cell vaccines improve the glioma microenvironment: Influence, challenges, and future directions

INTRODUCTION

Gliomas, especially the glioblastomas, are one of the most aggressive intracranial tumors with poor prognosis. This might be explained by the heterogeneity of tumor cells and the inhibitory immunological microenvironment. Dendritic cells (DCs), as the most potent in vivo functional antigen-presenting cells, link innate immunity with adaptive immunity. However, their function is suppressed in gliomas. Therefore, overcoming the dysfunction of DCs in the TME might be critical to treat gliomas.

METHOD

In this paper we proposed the specificity of the glioma microenvironment, analyzed the pathways leading to the dysfunction of DCs in tumor microenvironment of patients with glioma, summarized influence of DC-based immunotherapy on the tumor microenvironment and proposed new development directions and possible challenges of DC vaccines.

RESULT

DC vaccines can improve the immunosuppressive microenvironment of glioma patients. It will bring good treatment prospects to patients. We also proposed new development directions and possible challenges of DC vaccines, thus providing an integrated understanding of efficacy on DC vaccines for glioma treatment.

Immune landscape-based machine-learning-assisted subclassification, prognosis, and immunotherapy prediction for glioblastoma

Introduction

As a malignant brain tumor, glioblastoma (GBM) is characterized by intratumor heterogeneity, a worse prognosis, and highly invasive, lethal, and refractory natures. Immunotherapy has been becoming a promising strategy to treat diverse cancers. It has been known that there are highly heterogeneous immunosuppressive microenvironments among different GBM molecular subtypes that mainly include classical (CL), mesenchymal (MES), and proneural (PN), respectively. Therefore, an in-depth understanding of immune landscapes among them is essential for identifying novel immune markers of GBM.

Methods and results

In the present study, based on collecting the largest number of 109 immune signatures, we aim to achieve a precise diagnosis, prognosis, and immunotherapy prediction for GBM by performing a comprehensive immunogenomic analysis. Firstly, machine-learning (ML) methods were proposed to evaluate the diagnostic values of these immune signatures, and the optimal classifier was constructed for accurate recognition of three GBM subtypes with robust and promising performance. The prognostic values of these signatures were then confirmed, and a risk score was established to divide all GBM patients into high-, medium-, and low-risk groups with a high predictive accuracy for overall survival (OS). Therefore, complete differential analysis across GBM subtypes was performed in terms of the immune characteristics along with clinicopathological and molecular features, which indicates that MES shows much higher immune heterogeneity compared to CL and PN but has significantly better immunotherapy responses, although MES patients may have an immunosuppressive microenvironment and be more proinflammatory and invasive. Finally, the MES subtype is proved to be more sensitive to 17-AAG, docetaxel, and erlotinib using drug sensitivity analysis and three compounds of AS-703026, PD-0325901, and MEK1-2-inhibitor might be potential therapeutic agents.

Conclusion

Overall, the findings of this research could help enhance our understanding of the tumor immune microenvironment and provide new insights for improving the prognosis and immunotherapy of GBM patients.