Small Interfering RNA for Gliomas Treatment: Overcoming Hurdles in Delivery

Exploring the roles and clinical potential of exosome-derived non-coding RNAs in glioma

Non-coding accounts for 98 %-99 % of the human genome and performs many essential regulatory functions in eukaryotes, involved in cancer development and development. Non-coding RNAs are abundantly enriched in exosomes, which play a biological role as vectors. Some biofunctional non-coding RNAs are specifically designed as exosomes for the treatment of cancers such as glioma. Glioma is one of the most common primary tumors within the skull and has varying degrees of malignancy and histologic subtypes of grades I-IV. Gliomas are characterized by high malignancy and an abundant blood supply due to rapid cell proliferation and vascularization, often with a poor prognosis. Exosomal non-coding RNAs can be involved in the tumorigenesis process of glioma from multiple directions, such as angiogenesis, tumor proliferation, metastatic invasion, immune evasion, apoptosis, and autophagy. Therefore, non-coding RNAs in exosomes are suitable as markers or therapeutic targets for early diagnosis of diseases and for predicting the prognosis of a variety of diseases. Regulating exosome production and the level of exosomal non-coding RNA expression may be a new approach to prevent or eliminate glioma. In this review, we review the origin and characteristics of exosomal non-coding RNAs, and introduce the functional studies of exosomal non-coding RNAs in glioma and their potential clinical applications, in order to broaden new ideas for the treatment of glioma.

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.

Demystifying the potential of lipid-based nanocarriers in targeting brain malignancies

Drug targeting for brain malignancies is restricted due to the presence of the blood-brain barrier (BBB) and blood-brain tumor barrier (BBTB), which act as barriers between the blood and brain parenchyma. Certainly, the limited therapeutic options for brain malignancies have made notable progress with enhanced biological understanding and innovative approaches, such as targeted therapies and immunotherapies. These advancements significantly contribute to improving patient prognoses and represent a promising shift in the landscape of brain malignancy treatments. A more comprehensive understanding of the histology and pathogenesis of brain malignancies is urgently needed. Continued research focused on unraveling the intricacies of brain malignancy biology holds the key to developing innovative and tailored therapies that can improve patient outcomes. Lipid nanocarriers are highly effective drug delivery systems that significantly improve their solubility, bioavailability, and stability while also minimizing unwanted side effects. Surface-modified lipid nanocarriers (liposomes, niosomes, solid lipid nanoparticles, nanostructured lipid carriers, lipid nanocapsules, lipid-polymer hybrid nanocarriers, lipoproteins, and lipoplexes) are employed to improve BBB penetration and uptake through various mechanisms. This systematic review illuminates and covers various topics related to brain malignancies. It explores the different methods of drug delivery used in treating brain malignancies and delves into the benefits, limitations, and types of brain-targeted lipid-based nanocarriers. Additionally, this review discusses ongoing clinical trials and patents related to brain malignancy therapies and provides a glance into future perspectives for treating this condition.

Metabolic Reprogramming in Glioblastoma Multiforme: A Review of Pathways and Therapeutic Targets

Glioblastoma (GBM) is an aggressive and highly malignant primary brain tumor characterized by rapid growth and a poor prognosis for patients. Despite advancements in treatment, the median survival time for GBM patients remains low. One of the crucial challenges in understanding and treating GBMs involves its remarkable cellular heterogeneity and adaptability. Central to the survival and proliferation of GBM cells is their ability to undergo metabolic reprogramming. Metabolic reprogramming is a process that allows cancer cells to alter their metabolism to meet the increased demands of rapid growth and to survive in the often oxygen- and nutrient-deficient tumor microenvironment. These changes in metabolism include the Warburg effect, alterations in several key metabolic pathways including glutamine metabolism, fatty acid synthesis, and the tricarboxylic acid (TCA) cycle, increased uptake and utilization of glutamine, and more. Despite the complexity and adaptability of GBM metabolism, a deeper understanding of its metabolic reprogramming offers hope for developing more effective therapeutic interventions against GBMs.

Prospective Molecular Targets for Natural Killer Cell Immunotherapy against Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is the most common type of primary malignant brain tumor and has a dismal overall survival rate. To date, no GBM therapy has yielded successful results in survival for patients beyond baseline surgical resection, radiation, and chemotherapy. Immunotherapy has taken the oncology world by storm in recent years and there has been movement from researchers to implement the immunotherapy revolution into GBM treatment. Natural killer (NK) cell-based immunotherapies are a rising candidate to treat GBM from multiple therapeutic vantage points: monoclonal antibody therapy targeting tumor-associated antigens (TAAs), immune checkpoint inhibitors, CAR-NK cell therapy, Bi-specific killer cell engagers (BiKEs), and more. NK therapies often focus on tumor antigens for targeting. Here, we reviewed some common targets analyzed in the fight for GBM immunotherapy relevant to NK cells: EGFR, HER2, CD155, and IL-13Rα2. We further propose investigating the Lectin-like Transcript 1 (LLT1) and cell surface proliferating cell nuclear antigen (csPCNA) as targets for NK cell-based immunotherapy.

Multifunctional Fluoropolymer-Engineered Magnetic Nanoparticles to Facilitate Blood-Brain Barrier Penetration and Effective Gene Silencing in Medulloblastoma

Patients with brain cancers including medulloblastoma lack treatments that are effective long-term and without side effects. In this study, a multifunctional fluoropolymer-engineered iron oxide nanoparticle gene-therapeutic platform is presented to overcome these challenges. The fluoropolymers are designed and synthesized to incorporate various properties including robust anchoring moieties for efficient surface coating, cationic components to facilitate short interference RNA (siRNA) binding, and a fluorinated tail to ensure stability in serum. The blood-brain barrier (BBB) tailored system demonstrates enhanced BBB penetration, facilitates delivery of functionally active siRNA to medulloblastoma cells, and delivers a significant, almost complete block in protein expression within an in vitro extracellular acidic environment (pH 6.7) - as favored by most cancer cells. In vivo, it effectively crosses an intact BBB, provides contrast for magnetic resonance imaging (MRI), and delivers siRNA capable of slowing tumor growth without causing signs of toxicity - meaning it possesses a safe theranostic function. The pioneering methodology applied shows significant promise in the advancement of brain and tumor microenvironment-focused MRI-siRNA theranostics for the better treatment and diagnosis of medulloblastoma.

Therapeutic efficacy of a novel self-assembled immunostimulatory siRNA combining apoptosis promotion with RIG-I activation in gliomas

BACKGROUND

Current cancer therapies often fall short in addressing the complexities of malignancies, underscoring the urgent need for innovative treatment strategies. RNA interference technology, which specifically suppresses gene expression, offers a promising new approach in the fight against tumors. Recent studies have identified a novel immunostimulatory small-interfering RNA (siRNA) with a unique sequence (sense strand, 5'-C; antisense strand, 3'-GGG) capable of activating the RIG-I/IRF3 signaling pathway. This activation induces the release of type I and III interferons, leading to an effective antiviral immune response. However, this class of immunostimulatory siRNA has not yet been explored in cancer therapy.

METHODS

IsiBCL-2, an innovative immunostimulatory siRNA designed to suppress the levels of B-cell lymphoma 2 (BCL-2), contains a distinctive motif (sense strand, 5'-C; antisense strand, 3'-GGG). Glioblastoma cells were subjected to 100 nM isiBCL-2 treatment in vitro for 48 h. Morphological changes, cell viability (CCK-8 assay), proliferation (colony formation assay), migration/invasion (scratch test and Transwell assay), apoptosis rate, reactive oxygen species (ROS), and mitochondrial membrane potential (MMP) were evaluated. Western blotting and immunofluorescence analyses were performed to assess RIG-I and MHC-I molecule levels, and ELISA was utilized to measure the levels of cytokines (IFN-β and CXCL10). In vivo heterogeneous tumor models were established, and the anti-tumor effect of isiBCL-2 was confirmed through intratumoral injection.

RESULTS

IsiBCL-2 exhibited significant inhibitory effects on glioblastoma cell growth and induced apoptosis. BCL-2 mRNA levels were significantly decreased by 67.52%. IsiBCL-2 treatment resulted in an apoptotic rate of approximately 51.96%, accompanied by a 71.76% reduction in MMP and a 41.87% increase in ROS accumulation. Western blotting and immunofluorescence analyses demonstrated increased levels of RIG-I, MAVS, and MHC-I following isiBCL-2 treatment. ELISA tests indicated a significant increase in IFN-β and CXCL10 levels. In vivo studies using nude mice confirmed that isiBCL-2 effectively impeded the growth and progression of glioblastoma tumors.

CONCLUSIONS

This study introduces an innovative method to induce innate signaling by incorporating an immunostimulatory sequence (sense strand, 5'-C; antisense strand, 3'-GGG) into siRNA, resulting in the formation of RNA dimers through Hoogsteen base-pairing. This activation triggers the RIG-I signaling pathway in tumor cells, causing further damage and inducing a potent immune response. This inventive design and application of immunostimulatory siRNA offer a novel perspective on tumor immunotherapy, holding significant implications for the field.

Progressing nanotechnology to improve targeted cancer treatment: overcoming hurdles in its clinical implementation

The use of nanotechnology has the potential to revolutionize the detection and treatment of cancer. Developments in protein engineering and materials science have led to the emergence of new nanoscale targeting techniques, which offer renewed hope for cancer patients. While several nanocarriers for medicinal purposes have been approved for human trials, only a few have been authorized for clinical use in targeting cancer cells. In this review, we analyze some of the authorized formulations and discuss the challenges of translating findings from the lab to the clinic. This study highlights the various nanocarriers and compounds that can be used for selective tumor targeting and the inherent difficulties in cancer therapy. Nanotechnology provides a promising platform for improving cancer detection and treatment in the future, but further research is needed to overcome the current limitations in clinical translation.

Advances in Focused Ultrasound for the Treatment of Brain Tumors

Employing the full arsenal of therapeutics to treat brain tumors is limited by the relative impermeability of the blood-brain and blood-tumor barriers. In physiologic states, the blood-brain barrier serves a protective role by passively and actively excluding neurotoxic compounds; however, this functionality limits the penetrance of therapeutics into the tumor microenvironment. Focused ultrasound technology provides a method for overcoming the blood-brain and blood-tumor barriers through ultrasound frequency to transiently permeabilize or disrupt these barriers. Concomitant delivery of therapeutics has allowed for previously impermeable agents to reach the tumor microenvironment. This review details the advances in focused ultrasound in both preclinical models and clinical studies, with a focus on its safety profile. We then turn towards future directions in focused ultrasound-mediated therapies for brain tumors.