Mitochondrial Dysfunction, Macrophage, and Microglia in Brain Cancer

Green synthesis of metal nanocarriers: A perspective for targeting glioblastoma

Glioblastoma, the most aggressive brain cancer, is challenging to treat owing to the difficulty of crossing the blood-brain barrier, high recurrence rates and significant mortality. This review highlights the potential of green synthesis methods in developing metal nanoparticles (MNPs) as a sustainable solution for drug delivery systems targeting glioblastoma. We explore the unique properties and modes of action of MNPs synthesised through eco-friendly processes by focusing on their bioavailability and precision in brain targeting, and discuss the potential of MNPs to target glioblastoma at the molecular level. Integrating green synthesis into cancer therapeutics represents a novel paradigm shift towards treatments with higher efficacy and lower environmental impact, offering hope in the fight against glioblastoma.

Dysregulated inter-mitochondrial crosstalk in glioblastoma cells revealed by in situ cryo-electron tomography

Glioblastomas (GBMs) are the most lethal primary brain tumors with limited survival, even under aggressive treatments. The current therapeutics for GBMs are flawed due to the failure to accurately discriminate between normal proliferating cells and distinctive tumor cells. Mitochondria are essential to GBMs and serve as potential therapeutical targets. Here, we utilize cryo-electron tomography to quantitatively investigate nanoscale details of randomly sampled mitochondria in their native cellular context of GBM cells. Our results show that compared with cancer-free brain cells, GBM cells own more inter-mitochondrial junctions of several types for communications. Furthermore, our tomograms unveil microtubule-dependent mitochondrial nanotunnel-like bridges in the GBM cells as another inter-mitochondrial structure. These quantified inter-mitochondrial features, together with other mitochondria-organelle and intra-mitochondrial ones, are sufficient to distinguish GBM cells from cancer-free brain cells under scrutiny with predictive modeling. Our findings decipher high-resolution inter-mitochondrial structural signatures and provide clues for diagnosis and therapeutic interventions for GBM and other mitochondria-related diseases.

Engineering Exosomes to Specifically Target the Mitochondria of Brain Cells

Mitochondrial dysfunction is associated with various health conditions, including cardiovascular and neurodegenerative diseases. Mitochondrial-targeting therapy aims to restore or enhance mitochondrial function to treat or alleviate these conditions. Exosomes, small vesicles that cells secrete, containing a variety of biomolecules, are critical in cell-to-cell communication and have been studied as potential therapeutic agents. Exosome-based therapy has the potential to treat both cardiovascular and neurodegenerative diseases. Combining these two approaches involves using exosomes as carriers to transport mitochondrial-targeting agents to dysfunctional or damaged mitochondria within target cells. This article presents a new technique for engineering brain-derived exosomes that target mitochondria and has demonstrated promise in initial tests with primary neuron cells and healthy rats. This promising development represents a significant step forward in treating these debilitating conditions.

Mitochondria and Brain Disease: A Comprehensive Review of Pathological Mechanisms and Therapeutic Opportunities

Mitochondria play a vital role in maintaining cellular energy homeostasis, regulating apoptosis, and controlling redox signaling. Dysfunction of mitochondria has been implicated in the pathogenesis of various brain diseases, including neurodegenerative disorders, stroke, and psychiatric illnesses. This review paper provides a comprehensive overview of the intricate relationship between mitochondria and brain disease, focusing on the underlying pathological mechanisms and exploring potential therapeutic opportunities. The review covers key topics such as mitochondrial DNA mutations, impaired oxidative phosphorylation, mitochondrial dynamics, calcium dysregulation, and reactive oxygen species generation in the context of brain disease. Additionally, it discusses emerging strategies targeting mitochondrial dysfunction, including mitochondrial protective agents, metabolic modulators, and gene therapy approaches. By critically analysing the existing literature and recent advancements, this review aims to enhance our understanding of the multifaceted role of mitochondria in brain disease and shed light on novel therapeutic interventions.

Oncolytic viruses engineered to enforce cholesterol efflux restore tumor-associated macrophage phagocytosis and anti-tumor immunity in glioblastoma

The codependency of cholesterol metabolism sustains the malignant progression of glioblastoma (GBM) and effective therapeutics remain scarce. In orthotopic GBM models in male mice, we identify that codependent cholesterol metabolism in tumors induces phagocytic dysfunction in monocyte-derived tumor-associated macrophages (TAMs), resulting in disease progression. Manipulating cholesterol efflux with apolipoprotein A1 (ApoA1), a cholesterol reverse transporter, restores TAM phagocytosis and reactivates TAM-T cell antitumor immunity. Cholesterol metabolomics analysis of in vivo-sorted TAMs further reveals that ApoA1 mediates lipid-related metabolic remodeling and lowers 7-ketocholesterol levels, which directly inhibits tumor necrosis factor signaling in TAMs through mitochondrial translation inhibition. An ApoA1-armed oncolytic adenovirus is also developed, which restores antitumor immunity and elicits long-term tumor-specific immune surveillance. Our findings provide insight into the mechanisms by which cholesterol metabolism impairs antitumor immunity in GBM and offer an immunometabolic approach to target cholesterol disturbances in GBM.

Design, Synthesis, and Biological Evaluation of Novel Mitochondria-targeting Exosomes

Mitochondrial dysfunction is implicated in both brain tumors and neurodegenerative diseases, leading to various cellular abnormalities that can promote tumor growth and resistance to thera-pies, as well as impaired energy production and compromised neuronal function. Developing targeted therapies aimed at restoring mitochondrial function and improving overall cellular health could potentially be a promising approach to treating these conditions. Brain-derived exosomes (BR-EVs) have emerged as potential drug delivery vessels for neurological conditions. Herein, we report a new method for creating mitochondria-targeting exosomes and test its application in vitro and in vivo.

Advances in mitophagy and mitochondrial apoptosis pathway-related drugs in glioblastoma treatment

Glioblastoma (GBM) is the most common malignant tumor of the central nervous system (CNS). It is a leading cause of death among patients with intracranial malignant tumors. GBM exhibits intra- and inter-tumor heterogeneity, leading to drug resistance and eventual tumor recurrence. Conventional treatments for GBM include maximum surgical resection of glioma tissue, temozolomide administration, and radiotherapy, but these methods do not effectively halt cancer progression. Therefore, development of novel methods for the treatment of GBM and identification of new therapeutic targets are urgently required. In recent years, studies have shown that drugs related to mitophagy and mitochondrial apoptosis pathways can promote the death of glioblastoma cells by inducing mitochondrial damage, impairing adenosine triphosphate (ATP) synthesis, and depleting large amounts of ATP. Some studies have also shown that modern nano-drug delivery technology targeting mitochondria can achieve better drug release and deeper tissue penetration, suggesting that mitochondria could be a new target for intervention and therapy. The combination of drugs targeting mitochondrial apoptosis and autophagy pathways with nanotechnology is a promising novel approach for treating GBM.This article reviews the current status of drug therapy for GBM, drugs targeting mitophagy and mitochondrial apoptosis pathways, the potential of mitochondria as a new target for GBM treatment, the latest developments pertaining to GBM treatment, and promising directions for future research.

Ion Channels in Gliomas-From Molecular Basis to Treatment

Ion channels provide the basis for the nervous system's intrinsic electrical activity. Neuronal excitability is a characteristic property of neurons and is critical for all functions of the nervous system. Glia cells fulfill essential supportive roles, but unlike neurons, they also retain the ability to divide. This can lead to uncontrolled growth and the formation of gliomas. Ion channels are involved in the unique biology of gliomas pertaining to peritumoral pathology and seizures, diffuse invasion, and treatment resistance. The emerging picture shows ion channels in the brain at the crossroads of neurophysiology and fundamental pathophysiological processes of specific cancer behaviors as reflected by uncontrolled proliferation, infiltration, resistance to apoptosis, metabolism, and angiogenesis. Ion channels are highly druggable, making them an enticing therapeutic target. Targeting ion channels in difficult-to-treat brain tumors such as gliomas requires an understanding of their extremely heterogenous tumor microenvironment and highly diverse molecular profiles, both representing major causes of recurrence and treatment resistance. In this review, we survey the current knowledge on ion channels with oncogenic behavior within the heterogeneous group of gliomas, review ion channel gene expression as genomic biomarkers for glioma prognosis and provide an update on therapeutic perspectives for repurposed and novel ion channel inhibitors and electrotherapy.

Honey bee venom melittin increases the oxidant activity of cisplatin and kills human glioblastoma cells by stimulating the TRPM2 channel

Melittin (MLT) treatment is believed to enhance tumor cell death, apoptotic, and oxidative cytotoxic effects of cisplatin (CSP) via the modulation of Ca²⁺ channels in several cancer lines. The activation of TRPM2 mediated anticancer and CSP resistance actions via mitochondrial Ca²⁺ and Zn²⁺ accumulation-induced mitochondrial reactive free oxygen species (MitSOX) in the glioblastoma cells. The aim was to elucidate the effects of CSP and MLT combination via the TRPM2 stimulation on the tumor cell viability, cell number, cell death (propidium iodide/Hoechst rate), apoptosis, and MitSOX levels in the DBTRG-05MG cells. In the DBTRG-05MG cells, we induced four groups as control, MLT (2.5 μg/ml for 24 h), CSP (25 μM for 24 h), and CSP + MLT. The CSP-induced intracellular Ca²⁺ influxes to the TRPM2 activation were increased in the cells from coming H₂O₂ and ADP-Ribose. The influxes were decreased in the cells by the incubations of TRPM2 antagonists (ACA and carvacrol). The incubation of CSP increased the parameters of intracellular Ca²⁺ responses, mitochondria function, cytosolic free Zn²⁺ accumulation, apoptosis (caspase -3, -8, and -9), and MitSOX generation in the tumor cells. After the treatment of MLT with/without CSP, the parameters were further increased in the cells. In conclusion, the treatment of MLT increased the anticancer, tumor cell death, apoptotic, and oxidant effects of CSP in the glioblastoma tumor cells via activating the TRPM2. As a result, TRPM2 stimulation by MLT may be utilized as a successful agent in the CSP treatment of glioblastoma tumors.

Eicosapentaenoic acid enhanced apoptotic and oxidant effects of cisplatin via activation of TRPM2 channel in brain tumor cells

Cisplatin (CiSP) induced-overload Ca²⁺ entry results in the increase of mitochondrial oxidative stress and apoptosis in the cancer cell. TRPM2 cation channel is gated by the cytosolic ADP-ribose (ADPR) and reactive oxygen species (ROS). The high content of polyunsaturated fatty acid (PUFA) in the brain is a main target of ROS. Eicosapentaenoic acid (EPA) induces oxidant action via the enhance of PUFA content in the glioblastoma (DBTRG) cells. We hypothesized that a combination of CiSP and EPA may offer a potential therapy in the DBTRG cell by exerting the antitumor, oxidant, and apoptotic actions and stimulating Ca²⁺ influx and TRPM2 activity. In the DBTRG cells, we induced four groups as control, EPA (30 μM for 24 h), CiSP (25 μM for 24 h), and CiSP + EPA. The CiSP-induced intracellular Ca²⁺ responses to the TRPM2 activation were increased in the DBTRG cells from coming H₂O₂ and ADPR. The responses were decreased in the cells by the inhibitions of TRPM2 (ACA and 2/APB) and PARP/1 (DPQ and PJ34). The incubation of EPA further increased the intracellular Ca²⁺ responses, mitochondria function, and the generation of ROS in the DBTRGs. After the treatment of EPA, lipid peroxidation, apoptosis, cell death, caspase -3, -8, and -9 levels were further increased in the cells, although the levels of glutathione, glutathione peroxidase, cell numbers, and viability were further decreased in the cells. In summary, anticancer, apoptotic, and oxidant actions of CiSP were further increased via the activation of TRPM2 channel in the DBTRGs. Hence, TRPM2 stimulation via EPA could be used as an effective agent in the treatment of glioblastoma tumors with CiSP.

Photostable Red-Emitting Fluorescent Rhein-Magnesium(Ⅱ) Coordination Polymer Nanodot-Based Nanostructures With a Large Stokes Shift for Imaging Mitochondria in Cancer Cell

The mitochondria play a significant role in many cellular processes and are recognized as one of the most important therapeutic targets in cancer. Direct long-term imaging of the mitochondria is very crucial for treating cancer. However, the development of a red-emitting mitochondrial probe with a large Stokes shift and photostability remains highly challenging. Fluorescent metal complexes with superior physicochemical property have emerged as new fluorescent nanomaterials due to their increasing advantages in bioimaging. Herein, a luminescent pitaya-type nanostructure based on rhein-magnesium(II) (Rh-Mg) coordination polymer nanodots was used as a fluorescent nanoprobe to selectively image the mitochondria benefiting from the introduction of triphenylphosphine. The as-prepared Rh-Mg nanodot-based nanoprobe showed red emission peaking at 620 nm, a large Stokes shift (100 nm), and excellent photostability as compared with commercial mitochondrial probes. Due to these extraordinary features, this fluorescent nanoprobe was successfully used for mitochondrial targeting imaging of live cancer cell line Neuro-2a (mouse neuroblastoma) and BV2 microglial cells. Therefore, our results pave a new way for the design of fluorescent nanoprobes for imaging mitochondria in cancer cell.