Hybrid Magnetic Nanovectors Promote Selective Glioblastoma Cell Death through a Combined Effect of Lysosomal Membrane Permeabilization and Chemotherapy

Organelle-targeted small molecular photosensitizers for enhanced photodynamic therapy: a minireview for recent advances and potential applications

Photodynamic therapy (PDT) is a promising approach for cancer treatment that involves the use of photosensitizers to generate reactive oxygen species upon light irradiation, resulting in selective cytotoxicity. To enhance the efficiency of PDT, researchers have developed organelle-targeting photosensitizers that specifically accumulate in critical cellular organelles. This review provides a comprehensive overview of recent advancements in the development of organelle-targeting photosensitizers for PDT. Different organelles, including mitochondria, plasma membrane, lysosome, endoplasmic reticulum, lipid droplets, nucleus, and Golgi, have been targeted to improve the selectivity and effectiveness of PDT. Various strategies have been employed to design and synthesize these photosensitizers, optimizing their organelle-specific accumulation and photodynamic efficiency. This review discusses the principles and mechanisms underlying the design of organelle-targeting photosensitizers, along with their exceptional results achieved in preclinical studies. Furthermore, potential applications and challenges in the development of multi-organelles-targeting photosensitizers and the synergistic use of multiple photosensitizers targeting different organelles are highlighted. Overall, organelle-targeting photosensitizers offer a promising avenue for advancing the field of PDT and improving its clinical applicability.

Utilization of nanotechnology to surmount the blood-brain barrier in disorders of the central nervous system

Central nervous system (CNS) diseases are a major cause of disability and death worldwide. Due to the blood-brain barrier (BBB), drug delivery for CNS diseases is extremely challenging. Nano-delivery systems can overcome the limitations of BBB to deliver drugs to the CNS, improve the ability of drugs to target the brain and provide potential therapeutic methods for CNS diseases. At the same time, the choice of different drug delivery methods (bypassing BBB or crossing BBB) can further optimize the therapeutic effect of the nano-drug delivery system. This article reviews the different methods of nano-delivery systems to overcome the way BBB enters the brain. Different kinds of nanoparticles to overcome BBB were discussed in depth.

Transcytosis: an effective mechanism to enhance nanoparticle extravasation and infiltration through biological barriers

Nanoparticles (NPs)1have been explored as drugs carriers for treating tumors and central nervous system (CNS)2diseases and for oral administration. However, they lack satisfactory clinical efficacy due to poor extravasation and infiltration through biological barriers to target tissues. Most clinical antitumor NPs have been designed based on enhanced permeability and retention effects which are insufficient and heterogeneous in human tumors. The tight junctions33TJs: tight junctionsof the blood-brain barrier44BBB: blood-brain barrierand the small intestinal epithelium severely impede NPs from being transported into the CNS and blood circulation, respectively. By contrast, transcytosis enables NPs to bypass these physiological barriers and enhances their infiltration into target tissues by active transport. Here, we systematically review the mechanisms and putative application of NP transcytosis for targeting tumor and CNS tissues, explore oral NP administration, and propose future research directions in the field of NP transcytosis.

Nanoparticles in CNS Therapeutics: Pioneering Drug Delivery Advancements

INTRODUCTION

The incidence of Central Nervous System (CNS) disorders, including Parkinson's disease, Alzheimer's disease, stroke, and malignancies, has risen significantly in recent decades, contributing to millions of deaths annually. Efficacious treatment of these disorders requires medicines targeting the brain. The Blood-brain Barrier (BBB) poses a formidable challenge to effective drug delivery to the brain, hindering progress in CNS therapeutics. This review explores the latest developments in nanoparticulate carriers, highlighting their potential to overcome BBB limitations.

OBJECTIVE

This study aimed to evaluate and summarise the critical factors and pathways in the nanoparticle- based CNS targeted drug delivery.

METHODS

An extensive literature search was conducted, comprising the initial development of nanoparticle- based CNS-targeted drug delivery approaches to the latest advancements using various online search tools.

RESULTS

The properties of nanoparticles, such as type of nanoparticles, size, shape, surface charge, hydrophobicity, and surface functionalisation, along with properties of the BBB during normal and pathological conditions and their impact on the delivery of nanoparticles across the BBB, are identified and discussed here.

CONCLUSION

Important properties and pathways that determine the penetration of nanoparticles across the CNS are reviewed in this article, along with recent advances in the field.

Chlorin e6-Loaded Nanostructured Lipid Carriers Targeted by Angiopep-2: Advancing Photodynamic Therapy in Glioblastoma

Glioblastoma (GBM) is a highly aggressive brain tumor known for its resistance to standard treatments. Despite surgery being a primary option, it often leads to incomplete removal and high recurrence rates. Photodynamic therapy (PDT) holds promise as an adjunctive treatment, but safety concerns and the need for high-power lasers have limited its widespread use. This research addresses these challenges by introducing a novel PDT approach, using chlorin e6 (Ce6) enclosed in nanostructured lipid carriers (Ang-Ce6-NLCs) and targeted to GBM with the angiopep-2 peptide. Remarkably, a single 5-min irradiation session with LEDs at 660 nm and low power density (10 mW cm- 2) proves effective against GBM, while reducing safety risks associated with high-power lasers. Encapsulation improves Ce6 stability and performance in physiological environments, while angiopep-2 targeting enhances delivery to GBM cells, maximizing treatment efficacy and minimizing off-target effects. The findings demonstrate that Ang-Ce6-NLCs-mediated PDT brings about a significant reduction in GBM cell viability, increases oxidative stress, reduces tumor migration, and enhances apoptosis. Overall, such treatment holds potential as a safe and efficient intraoperative removal of GBM infiltrating cells that cannot be reached by surgery, using low-power LED light to minimize harm to surrounding healthy tissue while maximizing tumor treatment.

Development and characterization of lipid nanocapsules loaded with iron oxide nanoparticles for magnetic targeting to the blood-brain barrier

Brain drug delivery is severely hindered by the presence of the blood-brain barrier (BBB). Its functionality relies on the interactions of the brain endothelial cells with additional cellular constituents, including pericytes, astrocytes, neurons, or microglia. To boost brain drug delivery, nanomedicines have been designed to exploit distinct delivery strategies, including magnetically driven nanocarriers as a form of external physical targeting to the BBB. Herein, a lipid-based magnetic nanocarrier prepared by a low-energy method is first described. Magnetic nanocapsules with a hydrodynamic diameter of 256.7 ± 8.5 nm (polydispersity index: 0.089 ± 0.034) and a ξ-potential of -30.4 ± 0.3 mV were obtained. Transmission electron microscopy-energy dispersive X-ray spectroscopy analysis revealed efficient encapsulation of iron oxide nanoparticles within the oily core of the nanocapsules. Both thermogravimetric analysis and phenanthroline-based colorimetric assay showed that the iron oxide percentage in the final formulation was 12 wt.%, in agreement with vibrating sample magnetometry analysis, as the specific saturation magnetization of the magnetic nanocapsules was 12% that of the bare iron oxide nanoparticles. Magnetic nanocapsules were non-toxic in the range of 50-300 μg/mL over 72 h against both the human cerebral endothelial hCMEC/D3 and Human Brain Vascular Pericytes cell lines. Interestingly, higher uptake of magnetic nanocapsules in both cell types was evidenced in the presence of an external magnetic field than in the absence of it after 24 h. This increase in nanocapsules uptake was also evidenced in pericytes after only 3 h. Altogether, these results highlight the potential for magnetic targeting to the BBB of our formulation.

Recent advancements and clinical aspects of engineered iron oxide nanoplatforms for magnetic hyperthermia-induced cancer therapy

The pervasiveness of cancer is a global health concern posing a major threat in terms of mortality and incidence rates. Magnetic hyperthermia (MHT) employing biocompatible magnetic nanoparticles (MNPs) ensuring selective attachment to target sites, better colloidal stability and conserving nearby healthy tissues has garnered widespread acceptance as a promising clinical treatment for cancer cell death. In this direction, multifunctional iron oxide nanoparticles (IONPs) are of significant interest for improved cancer care due to finite size effect associated with inherent magnetic properties. This review offers a comprehensive perception of IONPs-mediated MHT from fundamentals to clinical translation, by elucidating the underlying mechanism of heat generation and the related influential factors. Biological mechanisms underlying MHT-mediated cancer cell death such as reactive oxygen species generation and lysosomal membrane permeabilization have been discussed in this review. Recent advances in biological interactions (in vitro and in vivo) of IONPs and their translation to clinical MHT applications are briefed. New frontiers and prospects of promising combination cancer therapies such as MHT with photothermal therapy, cancer starvation therapy and sonodynamic therapy are presented in detail. Finally, this review concludes by addressing current crucial challenges and proposing possible solutions to achieve clinical success.

The piper at the gates of brain: A systematic review of surface modification strategies on lipid nanoparticles to overcome the Blood-Brain-Barrier

The Blood-Brain Barrier (BBB) significantly impedes drug delivery to the central nervous system. Nanotechnology, especially surface-functionalized lipid nanoparticles, offers innovative approaches to overcome this barrier. However, choosing an effective functionalization strategy is challenging due to the lack of detailed comparative analysis in current literature. Our systematic review examined various functionalization strategies and their impact on BBB permeability from 2041 identified articles, of which 80 were included for data extraction. Peptides were the most common modification (18) followed by mixed strategies (12) proteins (9), antibodies (7), and other strategies (8). Interestingly, 26 studies showed BBB penetration with unmodified or modified nanoparticles using commonly applied strategies such as PEGylation or surfactant addition. Statistical analysis across 42 studies showed correlation between higher in vivo permeation improvements and nanoparticle type, size, and functionalization category. The highest ratios were found for nanostructured lipid carriers or biomimetic systems, in studies with particle sizes under 150 nm, and in those applying mixed functionalization strategies. The interstudy heterogeneity we observed highlights the importance of adopting standardized evaluation protocols to enhance comparability. Our systematic review aims to provide a comparative insight and identify future research directions in the development of more effective lipid nanoparticle systems for drug delivery to the brain to help improve the treatment of neurological and psychiatric disorders and brain tumours.

Peptide-Hitchhiking for the Development of Nanosystems in Glioblastoma

Glioblastoma (GBM) remains the epitome of aggressiveness and lethality in the spectrum of brain tumors, primarily due to the blood-brain barrier (BBB) that hinders effective treatment delivery, tumor heterogeneity, and the presence of treatment-resistant stem cells that contribute to tumor recurrence. Nanoparticles (NPs) have been used to overcome these obstacles by attaching targeting ligands to enhance therapeutic efficacy. Among these ligands, peptides stand out due to their ease of synthesis and high selectivity. This article aims to review single and multiligand strategies critically. In addition, it highlights other strategies that integrate the effects of external stimuli, biomimetic approaches, and chemical approaches as nanocatalytic medicine, revealing their significant potential in treating GBM with peptide-functionalized NPs. Alternative routes of parenteral administration, specifically nose-to-brain delivery and local treatment within the resected tumor cavity, are also discussed. Finally, an overview of the significant obstacles and potential strategies to overcome them are discussed to provide a perspective on this promising field of GBM therapy.

Ultrasound-Activated Piezoelectric Nanoparticles Trigger Microglia Activity Against Glioblastoma Cells

Glioblastoma multiforme (GBM) is the most aggressive brain cancer, characterized by a rapid and drug-resistant progression. GBM "builds" around its primary core a genetically heterogeneous tumor-microenvironment (TME), recruiting surrounding healthy brain cells by releasing various intercellular signals. Glioma-associated microglia (GAM) represent the largest population of collaborating cells, which, in the TME, usually exhibit the anti-inflammatory M2 phenotype, thus promoting an immunosuppressing environment that helps tumor growth. Conversely, "classically activated" M1 microglia could provide proinflammatory and antitumorigenic activity, expected to exert a beneficial effect in defeating glioblastoma. In this work, an immunotherapy approach based on proinflammatory modulation of the GAM phenotype is proposed, through a controlled and localized electrical stimulation. The developed strategy relies on the wireless ultrasonic excitation of polymeric piezoelectric nanoparticles coated with GBM cell membrane extracts, to exploit homotypic targeting in antiglioma applications. Such camouflaged nanotransducers locally generate electrical cues on GAM membranes, activating their M1 phenotype and ultimately triggering a promising anticancer activity. Collected findings open new perspectives in the modulation of immune cell activities through "smart" nanomaterials and, more specifically, provide an innovative auspicious tool in glioma immunotherapy.

Ultrasmall iron oxide nanoparticles with MRgFUS for enhanced magnetic resonance imaging of orthotopic glioblastoma

Ultrasmall iron oxide nanoparticles (USIO NPs) are expected to become the next generation T1 contrast agents; however, their diagnostic and therapeutic potential for primary brain tumors (such as glioblastoma multiforme, GBM) is yet to be explored. At present, the main challenge is the effective hindering of biological barriers, including the blood-brain barrier (BBB) and the blood-brain tumor barrier (BBTB). Herein, we aimed to investigate whether the USIO NPs, in combination with MR-guided focused ultrasound (MRgFUS), could intensify MR imaging of GBM. In this study, we presented zwitterionic USIO NPs for enhanced MR imaging of both xenografted and orthotopic GBM mouse models. We first synthesized citric-stabilized USIO NPs with a size of 3.19 ± 0.76 nm, modified with ethylenediamine, and decorated with 1,3-propanesultone (1,3-PS) to form USIO NPs-1,3-PS. The obtained USIO NPs-1,3-PS exhibited good cytocompatibility and cellular uptake efficiency. MRgFUS, in combination with microbubbles, provided a non-invasive and safe technique for BBB opening, which, in turn, promoted the delivery of USIO NPs-1,3-PS in orthotopic GBM. This developed USIO NP nanoplatform may improve the precision imaging of solid tumors and therapeutic efficacy in the central nervous system.

Drug-Loaded Polydopamine Nanoparticles for Chemo/Photothermal Therapy against Colorectal Cancer Cells

Colorectal cancer (CRC) is a common and deadly malignancy, ranking second in terms of mortality and third in terms of incidence on a global scale. The survival rates for CRC patients are unsatisfactory primarily because of the absence of highly effective clinical strategies. The efficacy of existing CRC treatments, such as chemotherapy (CT), is constrained by issues such as drug resistance and damage to healthy tissues. Alternative approaches such as photothermal therapy (PTT), while offering advantages over traditional therapies, suffer instead from a low efficiency in killing tumor cells when used alone. In this context, nanostructures can efficiently contribute to a selective and targeted treatment. Here, we combined CT and PTT by developing a nanoplatform based on polydopamine nanoparticles (PDNPs), selected for their biocompatibility, drug-carrying capabilities, and ability to produce heat upon exposure to near-infrared (NIR) irradiation. As a chemotherapy drug, sorafenib has been selected, a multikinase inhibitor already approved for clinical use. By encapsulating sorafenib in polydopamine nanoparticles (Sor-PDNPs), we were able to successfully improve the drug stability in physiological media and the consequent uptake by CRC cells, thereby increasing its therapeutic effects. Upon NIR stimulus, Sor-PDNPs can induce a temperature increment of about 10 °C, encompassing both PTT and triggering a localized and massive drug release. Sor-PDNPs were tested on healthy colon cells, showing minimal adverse outcomes; conversely, they demonstrated excellent efficacy against CRC cells, with a strong capability to hinder cancer cell proliferation and induce apoptosis. Obtained findings pave the way to new synergistic chemo-photothermal approaches, maximizing the therapeutic outcomes against CRC while minimizing side effects on healthy cells.

Lipid-based nanoparticles to address the limitations of GBM therapy by overcoming the blood-brain barrier, targeting glioblastoma stem cells, and counteracting the immunosuppressive tumor microenvironment

Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor, characterized by high heterogeneity, strong invasiveness, poor prognosis, and a low survival rate. A broad range of nanoparticles have been recently developed as drug delivery systems for GBM therapy owing to their inherent size effect and ability to cross the blood-brain barrier (BBB). Lipid-based nanoparticles (LBNPs), such as liposomes, solid lipid NPs (SLNs), and nano-structured lipid carriers (NLCs), have emerged as the most promising drug delivery system for the treatment of GBM because of their unique size, surface modification possibilities, and proven bio-safety. In this review, the main challenges of the current clinical treatment of GBM and the strategies on how novel LBNPs overcome them were explored. The application and progress of LBNP-based drug delivery systems in GBM chemotherapy, immunotherapy, and gene therapy in recent years were systematically reviewed, and the prospect of LBNPs for GBM treatment was discussed.

Targeting Lysosome for Enhanced Cancer Photodynamic/Photothermal Therapy in a "One Stone Two Birds" Pattern

Highly immunogenic programmed death of tumor cells, such as immunogenic cell death (ICD) and pyroptosis, strengthens antitumor responses and thus represents a promising target for cancer immunotherapy. However, the development of ICD and pyroptosis inducers remains challenging, and their efficiency is typically compromised by self-protective autophagy. Here, we report a potent ICD and pyroptosis-inducing strategy by coupling combined photodynamic/photothermal therapy (PTT/PDT) to biological processes in cancer cells. For this purpose, we rationally synthesize a lysosomal-targeting boron-dipyrromethene dimer (BDPd) with intense NIR absorption/emission, high reactive oxygen species (ROS) yield, and photothermal abilities, which can be self-assembled with Pluronic F127, producing lysosomal-acting nanomicelles (BDPd NPs) to facilitate cancer cell internalization of BDPd and generation of intracellular ROS. Owing to the favorable lysosomal-targeting ability of the morpholine group on BDPd, the intracellular BDPd NPs can accumulate in the lysosome and induce robust lysosomal damage in cancer cells upon 660 nm laser irradiation, which results in the synergetic induction of pyroptosis and ICD via activating NLRP3/GSDMD and caspase-3/GSDME pathways simultaneously. More importantly, PTT/PDT-induced self-protective autophagic degradation was blocked due to the dysfunction of lysosomes. Either intratumorally or intravenously, the injected BDPd NPs could markedly inhibit the growth of established tumor tissues upon laser activation, provoke local and systemic antitumor immune responses, and prolong the survival time in the mouse triple-negative breast cancer model. Collectively, this work represents a promising strategy to boost the therapeutic potential of PTT/PDT by coupling phototherapeutic reagents with the subcellular organelles, creating a "one stone two birds" pattern.

Drug-Loaded Lipid Magnetic Nanoparticles for Combined Local Hyperthermia and Chemotherapy against Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is a devastating tumor of the central nervous system, currently missing an effective treatment. The therapeutic gold standard consists of surgical resection followed by chemotherapy (usually with temozolomide, TMZ) and/or radiotherapy. TMZ does not, however, provide significant survival benefit after completion of treatment because of development of chemoresistance and of heavy side effects of systemic administration. Improvement of conventional treatments and complementary therapies are urgently needed to increase patient survival and quality of life. Stimuli-responsive lipid-based drug delivery systems offer promising prospects to overcome the limitations of the current treatments. In this work, multifunctional lipid-based magnetic nanovectors functionalized with the peptide angiopep-2 and loaded with TMZ (Ang-TMZ-LMNVs) were tested to enhance specific GBM therapy on an in vivo model. Exposure to alternating magnetic fields (AMFs) enabled magnetic hyperthermia to be performed, that works in synergy with the chemotherapeutic agent. Studies on orthotopic human U-87 MG-Luc2 tumors in nude mice have shown that Ang-TMZ-LMNVs can accumulate and remain in the tumor after local administration without crossing over into healthy tissue, effectively suppressing tumor invasion and proliferation and significantly prolonging the median survival time when combined with the AMF stimulation. This powerful synergistic approach has proven to be a robust and versatile nanoplatform for an effective GBM treatment.

Magnetic self-assembly of 3D multicellular microscaffolds: A biomimetic brain tumor-on-a-chip for drug delivery and selectivity testing

In recent years, the need for highly predictive brain cancer models to test new anticancer compounds and experimental therapeutic approaches has significantly increased. Realistic in vitro brain tumor-on-a-chip platforms would allow a more accurate selection of valid candidate drugs and nanomedicines, therefore alleviating the economic and ethical issues of unsuccessful studies in vivo. Here, we present a multi-functional self-assembled brain tumor-on-a-chip model characterized by 3D glioma cultures interfaced both to nonmalignant brain cells of the peritumoral niche and to a 3D-real-scale blood-brain barrier (BBB) microfluidic system. This platform allowed us to screen multiple features, such as BBB crossing capabilities, apoptotic efficacy against GBM cells, and side effects on nonmalignant brain cells of a promising anticancer drug, nutlin-3a, which is fundamental for the treatment of brain cancer.

A Novel Patient-Personalized Nanovector Based on Homotypic Recognition and Magnetic Hyperthermia for an Efficient Treatment of Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is the deadliest brain tumor, characterized by an extreme genotypic and phenotypic variability, besides a high infiltrative nature in healthy tissues. Apart from very invasive surgical procedures, to date, there are no effective treatments, and life expectancy is very limited. In this work, an innovative therapeutic approach based on lipid-based magnetic nanovectors is proposed, owning a dual therapeutic function: chemotherapy, thanks to an antineoplastic drug (regorafenib) loaded in the core, and localized magnetic hyperthermia, thanks to the presence of iron oxide nanoparticles, remotely activated by an alternating magnetic field. The drug is selected based on ad hoc patient-specific screenings; moreover, the nanovector is decorated with cell membranes derived from patients' cells, aiming at increasing homotypic and personalized targeting. It is demonstrated that this functionalization not only enhances the selectivity of the nanovectors toward patient-derived GBM cells, but also their blood-brain barrier in vitro crossing ability. The localized magnetic hyperthermia induces both thermal and oxidative intracellular stress that lead to lysosomal membrane permeabilization and to the release of proteolytic enzymes into the cytosol. Collected results show that hyperthermia and chemotherapy work in synergy to reduce GBM cell invasion properties, to induce intracellular damage and, eventually, to prompt cellular death.

Cell-Membrane-Coated and Cell-Penetrating Peptide-Conjugated Trimagnetic Nanoparticles for Targeted Magnetic Hyperthermia of Prostate Cancer Cells

Prostate malignancy represents the second leading cause of cancer-specific death among the male population worldwide. Herein, enhanced intracellular magnetic fluid hyperthermia is applied in vitro to treat prostate cancer (PCa) cells with minimum invasiveness and toxicity and highly specific targeting. We designed and optimized novel shape-anisotropic magnetic core-shell-shell nanoparticles (i.e., trimagnetic nanoparticles - TMNPs) with significant magnetothermal conversion following an exchange coupling effect to an external alternating magnetic field (AMF). The functional properties of the best candidate in terms of heating efficiency (i.e., Fe₃O₄@Mn_0.5Zn_0.5Fe₂O₄@CoFe₂O₄) were exploited following surface decoration with PCa cell membranes (CM) and/or LN1 cell-penetrating peptide (CPP). We demonstrated that the combination of biomimetic dual CM-CPP targeting and AMF responsiveness significantly induces caspase 9-mediated apoptosis of PCa cells. Furthermore, a downregulation of the cell cycle progression markers and a decrease of the migration rate in surviving cells were observed in response to the TMNP-assisted magnetic hyperthermia, suggesting a reduction in cancer cell aggressiveness.

A prediction model for magnetic particle imaging-based magnetic hyperthermia applied to a brain tumor model

BACKGROUND AND OBJECTIVE

Brain tumor is a global health concern at the moment. Thus far, the only treatments available are radiotherapy and chemotherapy, which have several drawbacks such as low survival rates and low treatment efficacy due to obstruction of the blood-brain barrier. Magnetic hyperthermia (MH) using magnetic nanoparticles (MNPs) is a promising non-invasive approach that has the potential for tumor treatment in deep tissues. Due to the limitations of the current drug-targeting systems, only a small proportion of the injected MNPs can be delivered to the desired area and the rest are distributed throughout the body. Thus, the application of conventional MH can lead to damage to healthy tissues.

METHODS

Magnetic particle imaging (MPI)-guided treatment platform for MH is an emerging approach that can be used for spatial localization of MH to arbitrarily selected regions by using the MPI magnetic field gradient. Although the feasibility of this method has been demonstrated experimentally, a multidimensional prediction model, which is of crucial importance for treatment planning, has not yet been developed. Hence, in this study, the time dependent magnetization equation derived by Martsenyuk, Raikher, and Shliomis (which is a macroscopic equation of motion derived from the Fokker-Planck equation for particles with Brownian relaxation mechanism) and the bio-heat equations have been used to develop and investigate a three-dimensional model that predicts specific loss power (SLP), its spatio-thermal resolution (temperature distribution), and the fraction of damage in brain tumors.

RESULTS

Based on the simulation results, the spatio-thermal resolution in focused heating depends, in a complex manner, on several parameters ranging from MNPs properties to magnetic fields characteristics, and coils configuration. However, to achieve a high performance in focused heating, the direction and the relative amplitude of the AC magnetic heating field with respect to the magnetic field gradient are among the most important parameters that need to be optimized. The temperature distribution and fraction of the damage in a simple brain model bearing a tumor were also obtained.

CONCLUSIONS

The complexity in the relationship between the MNPs properties and fields parameter imposes a trade-off between the heating efficiency of MNPs and the accuracy (resolution) of the focused heating. Therefore, the system configuration and field parameters should be chosen carefully for each specific treatment scenario. In future, the results of the model are expected to lead to the development of an MPI-guided MH treatment platform for brain tumor therapy. However, for more accurate quantitative results in such a platform, a magnetization dynamics model that takes into account coupled Néel-Brownian relaxation mechanism in the MNPs should be developed.

Advanced Strategies for Overcoming Endosomal/Lysosomal Barrier in Nanodrug Delivery

Nanocarriers have therapeutic potential to facilitate drug delivery, including biological agents, small-molecule drugs, and nucleic acids. However, their efficiency is limited by several factors; among which, endosomal/lysosomal degradation after endocytosis is the most important. This review summarizes advanced strategies for overcoming endosomal/lysosomal barriers to efficient nanodrug delivery based on the perspective of cellular uptake and intracellular transport mechanisms. These strategies include promoting endosomal/lysosomal escape, using non-endocytic methods of delivery to directly cross the cell membrane to evade endosomes/lysosomes and making a detour pathway to evade endosomes/lysosomes. On the basis of the findings of this review, we proposed several promising strategies for overcoming endosomal/lysosomal barriers through the smarter and more efficient design of nanodrug delivery systems for future clinical applications.

Lipid-Based Nanocarriers in the Treatment of Glioblastoma Multiforme (GBM): Challenges and Opportunities

Glioblastoma multiforme (also known as glioblastoma; GBM) is one of the most malignant types of brain tumors that occurs in the CNS. Treatment strategies for glioblastoma are majorly comprised of surgical resection, radiotherapy, and chemotherapy along with combination therapy. Treatment of GBM is itself a tedious task but the involved barriers in GBM are one of the main impediments to move one step closer to the treatment of GBM. Basically, two of the barriers are of utmost importance in this regard, namely blood brain barrier (BBB) and blood brain tumor barrier (BBTB). This review will address different challenges and barriers in the treatment of GBM along with their etiology. The role and recent progress of lipid-based nanocarriers like liposomes, solid lipid nanocarriers (SLNs), nanostructured lipid carriers (NLCs), lipoplexes, and lipid hybrid carriers in the effective management of GBM will be discussed in detail.

Interactions of Nanoscale Self-Assembled Peptide-Based Assemblies with Glioblastoma Cell Models and Spheroids

Peptide nanoassemblies have garnered remarkable importance in the development of novel nanoscale biomaterials for drug delivery into tumor cells. Taking advantage of receptor mediated recognition of two known peptides, angiopep-2 (TFFYGGSRGKRNNFKTEEY) and A-COOP-K (ACGLSGLC10 VAK) that bind to the over-expressed receptors low density lipoprotein (LRP-1) and fatty acid binding protein (FABP3) respectively, we have developed new peptide conjugates by combining the anti-inflammatory, antitumor compound azelaic acid with angiopep-2, which efficiently self-assembled into nanofibers. Those nanofibers were then functionalized with the A-COOP-K sequence and formed supramolecular hierarchical structures that were found to entrap the chemotherapeutic drug doxorubicin efficaciously. Furthermore, the nanoassemblies were found to release the drug in a dose-dependent manner and showed a stepwise increase over a period of 2 weeks under acidic conditions. Two cell lines (U-87-MG and U-138-MG) were utilized as models for glioblastoma cells grown in the presence of serum and under serum-free conditions to mimic the growth conditions of natural tumors. The drug entrapped assemblies were found to inhibit the cell proliferation of both U-87 and U-138MG glioblastoma cells. Three dimensional spheroids of different sizes were grown to mimic the tumors and evaluate the efficacy of drug release and internalization. Our results indicated that the nanoassemblies were found to have higher internalization of DOX and were well-spread throughout the spheroids grown, particularly under serum-free conditions. The nanoassemblies also displayed blood-brain barrier penetration when tested with a multicellular in vitro model. Such self-assembled nanostructures with targeting ability may provide a suitable platform for the development of new peptide-based biomaterials that can provide more insights about the mechanistic approach for drug delivery for not only 2D cell cultures but also 3D tumoroids that mimic the tumor microenvironments.

Recent Advances on Surface-Modified GBM Targeted Nanoparticles: Targeting Strategies and Surface Characterization

Glioblastoma multiforme (GBM) is the most common malignant brain tumor, associated with low long-term survival. Nanoparticles (NPs) developed against GBM are a promising strategy to improve current therapies, by enhancing the brain delivery of active molecules and reducing off-target effects. In particular, NPs hold high potential for the targeted delivery of chemotherapeutics both across the blood-brain barrier (BBB) and specifically to GBM cell receptors, pathways, or the tumor microenvironment (TME). In this review, the most recent strategies to deliver drugs to GBM are explored. The main focus is on how surface functionalizations are essential for BBB crossing and for tumor specific targeting. We give a critical analysis of the various ligand-based approaches that have been used to target specific cancer cell receptors and the TME, or to interfere with the signaling pathways of GBM. Despite the increasing application of NPs in the clinical setting, new methods for ligand and surface characterization are needed to optimize the synthesis, as well as to predict their in vivo behavior. An expert opinion is given on the future of this research and what is still missing to create and characterize a functional NP system for improved GBM targeting.

Curcumin and N-Acetylcysteine Nanocarriers Alone or Combined with Deferoxamine Target the Mitochondria and Protect against Neurotoxicity and Oxidative Stress in a Co-Culture Model of Parkinson's Disease

As the blood-brain barrier (BBB) prevents most compounds from entering the brain, nanocarrier delivery systems are frequently being explored to potentially enhance the passage of drugs due to their nanometer sizes and functional characteristics. This study aims to investigate whether Pluronic® F68 (P68) and dequalinium (DQA) nanocarriers can improve the ability of curcumin, n-acetylcysteine (NAC) and/or deferoxamine (DFO), to access the brain, specifically target mitochondria and protect against rotenone by evaluating their effects in a combined Transwell® hCMEC/D3 BBB and SH-SY5Y based cellular Parkinson’s disease (PD) model. P68 + DQA nanoformulations enhanced the mean passage across the BBB model of curcumin, NAC and DFO by 49%, 28% and 49%, respectively (p < 0.01, n = 6). Live cell mitochondrial staining analysis showed consistent co-location of the nanocarriers within the mitochondria. P68 + DQA nanocarriers also increased the ability of curcumin and NAC, alone or combined with DFO, to protect against rotenone induced cytotoxicity and oxidative stress by up to 19% and 14% (p < 0.01, n = 6), as measured by the MTT and mitochondrial hydroxyl radical assays respectively. These results indicate that the P68 + DQA nanocarriers were successful at enhancing the protective effects of curcumin, NAC and/or DFO by increasing the brain penetrance and targeted delivery of the associated bioactives to the mitochondria in this model. This study thus emphasises the potential effectiveness of this nanocarrier strategy in fully utilising the therapeutic benefit of these antioxidants and lays the foundation for further studies in more advanced models of PD.

Effects of postoperative radiotherapy and docetaxel and PD-1 inhibitors on the survival and safety of glioblastoma patients: a systematic review and meta-analysis

Background

The present standard treatment rarely allows the complete removal of glioblastoma (GBM). So postoperative treatments are provided to prevent or delay tumor recurrence. The overall survival (OS) rate and safety of postoperative chemotherapy alone, or combined with radiotherapy (RT), or programmed cell death-1 (PD-1) inhibitor in GBM is still unclear. The present goal was to explore postoperative treatment's effect on the survival and safety of patients with GBM.

Methods

We searched the mainstream online databases for clinical studies of RT and chemotherapy and PD-1 inhibitors in the treatment of GBM published up to May 2020. The patients in the experimental group accepted an anti-PD-1 drug alone and RT + chemotherapy, whereas the controlled patients were treated with docetaxel alone. The literature qualities were assessed using Cochrane Risk of Bias 2.0, and studies were assigned. The meta-analysis was conducted by RevMan 5.4 software.

Results

A total of 927 articles were identified through the online database search. The articles unable to meet the inclusion criteria were excluded leaving 6 studies for inclusion in the study. Compared with docetaxel-based chemotherapy for GBM, combined RT chemotherapy and PD-1 inhibitor therapy had better OS [mean difference (MD), -1.75; 95% confidence interval (CI): -2.99 to -0.51; P=0.006] and progression-free survival (PFS) and a lower incidence of adverse reactions (MD, -7.03; 95% CI: -7.64 to -6.42; P<0.00001) above grade III.

Conclusions

Postoperative combination of RT and chemotherapy and PD-1 inhibitors had some advantages over docetaxel in terms of effectiveness. More clinical trials are needed to confirm effectiveness.

Insights into the Effect of Magnetic Confinement on the Performance of Magnetic Nanocomposites in Magnetic Hyperthermia and Magnetic Resonance Imaging

The combination of superparamagnetic iron oxide nanoparticles (SPIONs) and lipid matrices enables the integration of imaging, drug delivery, and therapy functionalities into smart theranostic nanocomposites. SPION confinement creates new interactions primarily among the embedded SPIONs and then between the nanocomposites and the surroundings. Understanding the parameters that rule these interactions in real interacting (nano)systems still represents a challenge, making it difficult to predict or even explain the final (magnetic) behavior of such systems. Herein, a systematic study focused on the performance of a magnetic nanocomposite as a magnetic resonance imaging (MRI) contrast agent and magnetic hyperthermia (MH) effector is presented. The effect of stabilizing agents and magnetic loading on the final physicochemical and, more importantly, functional properties (i.e., blocking temperature, specific absorption rate, relaxivity) was studied in detail.

Micro-Nanocarriers Based Drug Delivery Technology for Blood-Brain Barrier Crossing and Brain Tumor Targeting Therapy

The greatest obstacle to using drugs to treat brain tumors is the blood-brain barrier (BBB), making it difficult for conventional drug molecules to enter the brain. Therefore, how to safely and effectively penetrate the BBB to achieve targeted drug delivery to brain tumors has been a challenging research problem. With the intensive research in micro- and nanotechnology in recent years, nano drug-targeted delivery technologies have shown great potential to overcome this challenge, such as inorganic nanocarriers, organic polymer-carriers, liposomes, and biobased carriers, which can be designed in different sizes, shapes, and surface functional groups to enhance their ability to penetrate the BBB and targeted drug delivery for brain tumors. In this review, the composition and overcoming patterns of the BBB are detailed, and then the hot research topics of drug delivery carriers for brain tumors in recent years are summarized, and their mechanisms of action on the BBB and the factors affecting drug delivery are described in detail, and the effectiveness of targeted therapy for brain tumors is evaluated. Finally, the challenges and dilemmas in developing brain tumor drug delivery systems are discussed, which will be promising in the future for targeted drug delivery to brain tumors based on micro-nanocarriers technology.

Revealing Angiopep-2/LRP1 Molecular Interaction for Optimal Delivery to Glioblastoma (GBM)

Background: The family of synthetic peptide angiopeps, and particularly angiopep-2 (ANG-2) demonstrated the ability preclinically and clinically to shuttle active molecules across the blood–brain barrier (BBB) and selectively toward brain tumor cells. The literature has also proved that the transport occurs through a specific receptor-mediated transcytosis of the peptide by LRP-1 receptors present both on BBB and tumor cell membranes. However, contradictory results about exploiting this promising mechanism to engineer complex delivery systems, such as nanoparticles, are being obtained. Methodology: For this reason, we applied a molecular docking (MD)-based strategy to investigate the molecular interaction of ANG-2 and the LRP-1 ligand-binding moieties (CR56 and CR17), clarifying the impact of peptide conjugation on its transport mechanism. Results: MD results proved that ANG-2/LRP-1 binding involves the majority of ANG-2 residues, is characterized by high binding energies, and that it is site-specific for CR56 where the binding to 929ASP recalls a transcytosis mechanism, resembling the binding of the receptor to the receptor-associated protein. On the other hand, ANG-2 binding to CR17 is less site-specific but, as proved for apolipoprotein internalization in physiological conditions, it involves the ANG-2 lysin residue. Conclusions: Overall, our results proved that ANG-2 energetic interaction with the LRP-1 receptor is not hindered if specific residues of the peptide are chemically crosslinked to simple or complex engineered delivery systems.

Bacteria loaded with glucose polymer and photosensitive ICG silicon-nanoparticles for glioblastoma photothermal immunotherapy

Bacteria can bypass the blood-brain barrier (BBB), suggesting the possibility of employment of bacteria for combating central nervous system diseases. Herein, we develop a bacteria-based drug delivery system for glioblastoma (GBM) photothermal immunotherapy. The system, which we name as ‘Trojan bacteria’, consists of bacteria loaded with glucose polymer and photosensitive ICG silicon-nanoparticles. In an orthotopic GBM mouse model, we demonstrate that the intravenously injected bacteria bypass the BBB, targeting and penetrating GBM tissues. Upon 808 nm-laser irradiation, the photothermal effects produced by ICG allow the destruction of bacterial cells and the adjacent tumour cells. Furthermore, the bacterial debris as well as the tumour-associated antigens promote antitumor immune responses that prolong the survival of GBM-bearing mice. Moreover, we demonstrate the residual bacteria are effectively eliminated from the body, supporting the potential therapeutic use of this system.

Different blood-brain barrier permeable systems, such as bacteria loaded with chemotherapy, have been proposed to treat glioblastoma. Here, the authors generate bacteria loaded with glucose polymer and photosensitive ICG silicon-nanoparticles to eliminate bacteria-infected glioblastoma cells and induce an anti-tumour immune response upon photothermal therapy.

Metal-Based Nanostructured Therapeutic Strategies for Glioblastoma Treatment-An Update

Glioblastoma (GBM) is the most commonly diagnosed and most lethal primary malignant brain tumor in adults. Standard treatments are ineffective, and despite promising results obtained in early phases of experimental clinical trials, the prognosis of GBM remains unfavorable. Therefore, there is need for exploration and development of innovative methods that aim to establish new therapies or increase the effectiveness of existing therapies. One of the most exciting new strategies enabling combinatory treatment is the usage of nanocarriers loaded with chemotherapeutics and/or other anticancer compounds. Nanocarriers exhibit unique properties in antitumor therapy, as they allow highly efficient drug transport into cells and sustained intracellular accumulation of the delivered cargo. They can be infused into and are retained by GBM tumors, and potentially can bypass the blood-brain barrier. One of the most promising and extensively studied groups of nanostructured therapeutics are metal-based nanoparticles. These theranostic nanocarriers demonstrate relatively low toxicity, thus they might be applied for both diagnosis and therapy. In this article, we provide an update on metal-based nanostructured constructs in the treatment of GBM. We focus on the interaction of metal nanoparticles with various forms of electromagnetic radiation for use in photothermal, photodynamic, magnetic hyperthermia and ionizing radiation sensitization applications.

Modulation of Local Cellular Activities using a Photothermal Dye-Based Subcellular-Sized Heat Spot

Thermal engineering at the microscale, such as the regulation and precise evaluation of the temperature within cellular environments, is a major challenge for basic biological research and biomaterials development. We engineered a polymeric nanoparticle having a fluorescent temperature sensory dye and a photothermal dye embedded in the polymer matrix, named nanoheater-thermometer (nanoHT). When nanoHT is illuminated with a near-infrared laser at 808 nm, a subcellular-sized heat spot is generated in a live cell. Fluorescence thermometry allows the temperature increment to be read out concurrently at individual heat spots. Within a few seconds of an increase in temperature by approximately 11.4 °C from the base temperature (37 °C), we observed the death of HeLa cells. The cell death was observed to be triggered from the exact local heat spot at the subcellular level under the fluorescence microscope. Furthermore, we demonstrate the application of nanoHT for the induction of muscle contraction in C2C12 myotubes by heat release. We successfully showed heat-induced contraction to occur in a limited area of a single myotube based on the alteration of protein-protein interactions related to the contraction event. These results demonstrate that even a single heat spot provided by a photothermal material can be extremely effective in altering cellular functions.

Nanodrugs Detonate Lysosome Bombs

Cancer cell lysosomes contain various hydrolases and non-degraded substrates that are corrosive enough to destroy cancer cells. However, many traditional small molecule drugs targeting lysosomes have strong side effects because they cannot effectively differentiate between normal and cancer cells. Most lysosome-based research has focused on inducing mild lysosomal membrane permeabilization (LMP) to release anticancer drugs from lysosomal traps into the cancer cell cytoplasm. In fact, lysosomes are particularly powerful "bombs". Achieving cancer cell-selective LMP induction may yield high-efficiency anticancer effects and extremely low side effects. Nanodrugs have diverse and combinable properties and can be specifically designed to selectively induce LMP in cancer cells by taking advantage of the differences between cancer cells and normal cells. Although nanodrugs-induced LMP has made great progress recently, related reviews remain rare. Herein, we first comprehensively summarize the advances in nanodrugs-induced LMP. Next, we describe the different nanodrugs-induced LMP strategies, namely nanoparticles aggregation-induced LMP, chemodynamic therapy (CDT)-induced LMP, and magnetic field-induced LMP. Finally, we analyze the prospect of nanodrugs-induced LMP and the challenges to overcome. We believe this review provides a unique perspective and inspiration for designing lysosome-targeting drugs.

Non-apoptotic cell death-based cancer therapy: Molecular mechanism, pharmacological modulators, and nanomedicine

As an emerging cancer therapeutic target, non-apoptotic cell death such as ferroptosis, necroptosis and pyroptosis, etc., has revealed significant potential in cancer treatment for bypassing apoptosis to enhance the undermined therapeutic efficacy triggered by apoptosis resistance. A variety of anticancer drugs, synthesized compounds and natural products have been proven recently to induce non-apoptotic cell death and exhibit excellent anti-tumor effects. Moreover, the convergence of nanotechnology with functional materials and biomedicine science has provided tremendous opportunities to construct non-apoptotic cell death-based nanomedicine for innovative cancer therapy. Nanocarriers are not only employed in targeted delivery of non-apoptotic inducers, but also used as therapeutic components to induce non-apoptotic cell death to achieve efficient tumor treatment. This review first introduces the main characteristics, the mechanism and various pharmacological modulators of different non-apoptotic cell death forms, including ferroptosis, necroptosis, pyroptosis, autophagy, paraptosis, lysosomal-dependent cell death, and oncosis. Second, we comprehensively review the latest progresses of nanomedicine that induces various forms of non-apoptotic cell death and focus on the nanomedicine targeting different pathways and components. Furthermore, the combination therapies of non-apoptotic cell death with photothermal therapy, photodynamic therapy, immunotherapy and other modalities are summarized. Finally, the challenges and future perspectives in this regard are also discussed.

Ultrasound-responsive nutlin-loaded nanoparticles for combined chemotherapy and piezoelectric treatment of glioblastoma cells

Glioblastoma multiforme (GBM), also known as grade IV astrocytoma, represents the most aggressive primary brain tumor. The complex genetic heterogeneity, the acquired drug resistance, and the presence of the blood-brain barrier (BBB) limit the efficacy of the current therapies, with effectiveness demonstrated only in a small subset of patients. To overcome these issues, here we propose an anticancer approach based on ultrasound-responsive drug-loaded organic piezoelectric nanoparticles. This anticancer nanoplatform consists of nutlin-3a-loaded ApoE-functionalized P(VDF-TrFE) nanoparticles, that can be remotely activated with ultrasound-based mechanical stimulations to induce drug release and to locally deliver anticancer electric cues. The combination of chemotherapy treatment with chronic piezoelectric stimulation resulted in activation of cell apoptosis and anti-proliferation pathways, induction of cell necrosis, inhibition of cancer migration, and reduction of cell invasiveness in drug-resistant GBM cells. Obtained results pave the way for the use of innovative multifunctional nanomaterials in less invasive and more focused anticancer treatments, able to reduce drug resistance in GBM.

A review of recent advances in magnetic nanoparticle-based theranostics of glioblastoma

Rapid vascular growth, infiltrative cells and high tumor heterogenicity are some glioblastoma multiforme (GBM) characteristics, making it the most lethal form of brain cancer. Low efficacy of the conventional treatment modalities leads to rampant disease progression and a median survival of 15 months. Magnetic nanoparticles (MNPs), due to their unique physical features/inherent abilities, have emerged as a suitable theranostic platform for targeted GBM treatment. Thus, new strategies are being designed to enhance the efficiency of existing therapeutic techniques such as chemotherapy, radiotherapy, and so on, using MNPs. Herein, the limitations of the current therapeutic strategies, the role of MNPs in mitigating those inadequacies, recent advances in the MNP-based theranostics of GBM and possible future directions are discussed.

Superparamagnetic iron oxide nanoparticles for magnetic hyperthermia: Recent advancements, molecular effects, and future directions in the omics era

Superparamagnetic iron oxide nanoparticles have attracted attention in the biomedical field thanks to their ability to prompt hyperthermia in response to an alternated magnetic field. Hyperthermia is well-known for inducing...

Deciphering Nanoparticle Trafficking into Glioblastomas Uncovers an Augmented Antitumor Effect of Metronomic Chemotherapy

Nanoparticles have been explored in glioblastomas as they can traverse the blood-brain barrier and target glioblastoma selectively. However, direct observation of nanoparticle trafficking into glioblastoma cells and their underlying intracellular fate after systemic administration remains uncharacterized. Here, based on high-resolution transmission electron microscopy experiments of an intracranial glioblastoma model, it is shown that ligand-modified nanoparticles can traverse the blood-brain barrier, endocytose into the lysosomes of glioblastoma cells, and undergo endolysosomal escape upon photochemical ionization. Moreover, an optimal dose of metronomic chemotherapy using dual-drug-loaded nanocarriers can induce an augmented antitumor effect directly on tumors, which has not been recognized in previous studies. Metronomic chemotherapy enhances antitumor effects 3.5-fold compared with the standard chemotherapy regimen using the same accumulative dose in vivo. This study provides a conceptual framework that can be used to develop metronomic nanoparticle regimens as a safe and viable therapeutic strategy for treating glioblastomas and other advanced-stage solid tumors.

Multifunctional nanozyme for multimodal imaging-guided enhanced sonodynamic therapy by regulating the tumor microenvironment

Sonodynamic therapy (SDT) is a highly promising approach for cancer therapy, but its efficacy is severely hampered by the low specificity of sonosensitizers and the unfavorable characteristics of the tumor microenvironment (TME), such as hypoxia and glutathione (GSH) overexpression. To solve these problems, in this work, we encapsulated IR780 and MnO₂ in PLGA and linked Angiopep-2 (Ang) to synthesize a multifunctional nanozyme (Ang-IR780-MnO₂-PLGA, AIMP) to enhance SDT. With Ang functionalization to facilitate blood-brain barrier (BBB) penetration and glioma targeting, and through the function of IR780, these nanoparticles (NPs) showed improved targeting of cancer cells, especially mitochondria, and spread deep into tumor centers. Upon low-intensity focused ultrasound (LIFU) irradiation, reactive oxygen species (ROS) were produced and induced tumor cell apoptosis. Combined with the specific mitochondria-targeting ability of IR780, the sonodynamic effects were amplified because mitochondria are sensitive to ROS. In addition, MnO₂ exhibited enzyme-like activity, reacting with the high levels of hydrogen protons (H⁺), H₂O₂ and GSH in the TME to continuously produce oxygen and consume GSH, which further enhanced the effect of SDT. Moreover, Mn²⁺ can be released in response to TME stimulation and used as a magnetic resonance (MR) contrast agent. In addition, IR780 has photoacoustic (PA)/fluorescence (FL) imaging capabilities. Our results demonstrated that AIMP NPs subjected to LIFU triggering maximally enhanced the therapeutic effect of SDT by multiple mechanisms, including multiple targeting, deep penetration, oxygen supply in situ and GSH depletion, thereby significantly inhibiting tumor growth and distal metastasis without systemic toxicity. In summary, this multifunctional nanozyme provides a promising strategy for cancer diagnosis and treatment under the intelligent guidance of multimodal imaging (PA/FL/MR) and may be a safe clinical translational method.

Light-Activated Biomedical Applications of Chlorophyll Derivatives

Tetrapyrroles are the basis of essential physiological functions in most living organisms. These compounds represent the basic scaffold of porphyrins, chlorophylls, and bacteriochlorophylls, among others. Chlorophyll derivatives, obtained by the natural or artificial degradation of chlorophylls, present unique properties, holding great potential in the scientific and medical fields. Indeed, they can act as cancer-preventing agents, antimutagens, apoptosis inducers, efficient antioxidants, as well as antimicrobial and immunomodulatory molecules. Moreover, thanks to their peculiar optical properties, they can be exploited as photosensitizers for photodynamic therapy and as vision enhancers. Most of these molecules, however, are highly hydrophobic and poorly soluble in biological fluids, and may display undesired toxicity due to accumulation in healthy tissues. The advent of nanomedicine has prompted the development of nanoparticles acting as carriers for chlorophyll derivatives, facilitating their targeted administration with demonstrated applicability in diagnosis and therapy. In this review, the chemical and physical properties of chlorophyll derivatives that justify their usage in the biomedical field, with particular regard to light-activated dynamics are described. Their role as antioxidants and photoactive agents are discussed, introducing the most recent nanomedical applications and focusing on inorganic and organic nanocarriers exploited in vitro and in vivo.

Circumventing Drug Treatment? Intrinsic Lethal Effects of Polyethyleneimine (PEI)-Functionalized Nanoparticles on Glioblastoma Cells Cultured in Stem Cell Conditions

Simple Summary

Glioblastoma (GB) is the most frequent brain cancer that is highly difficult to treat. As with many cancer types, associated cancer stem cells can act as a reservoir of cancer-initiating cells, constituting a major hurdle for successful therapy. Herein, we report on a discovery of the intrinsic capability of polyethyleneimine-functionalized nanoparticles (PEI-NPs) to selectively eradicate glioblastoma stem cells (GSCs), contrary to current drug-based approaches to target and successfully eradicate GB. Already at negligible doses, PEI-NPs, without any anticancer therapeutic, very potently killed multiple GSC lines but not GB cells without stem cell characteristics. Moreover, PEI-NPs was observed in tumors in mice after both intravenous and intranasal administration, where the latter constitute a non-invasive administration route for drug delivery to the brain. These results, in turn, suggest that PEI-NPs can successfully cross the blood-brain barrier for the eradication of GSCs even without any anticancer drug, whereas the same NP platform can also be used for drug delivery thus opening up potential to reach synergistic therapeutic effects. This highly surprising intrinsic effect of the NP system on both the mechanistic action and specificity of GSC eradication puts forward a promising novel aspect of nanoparticles in medicine.

Abstract

Glioblastoma (GB) is the most frequent malignant tumor originating from the central nervous system. Despite breakthroughs in treatment modalities for other cancer types, GB remains largely irremediable due to the high degree of intratumoral heterogeneity, infiltrative growth, and intrinsic resistance towards multiple treatments. A sub-population of GB cells, glioblastoma stem cells (GSCs), act as a reservoir of cancer-initiating cells and consequently, constitute a significant challenge for successful therapy. In this study, we discovered that PEI surface-functionalized mesoporous silica nanoparticles (PEI-MSNs), without any anti-cancer drug, very potently kill multiple GSC lines cultured in stem cell conditions. Very importantly, PEI-MSNs did not affect the survival of established GB cells, nor other types of cancer cells cultured in serum-containing medium, even at 25 times higher doses. PEI-MSNs did not induce any signs of apoptosis or autophagy. Instead, as a potential explanation for their lethality under stem cell culture conditions, we demonstrate that the internalized PEI-MSNs accumulated inside lysosomes, subsequently causing a rupture of the lysosomal membranes. We also demonstrate blood–brain-barrier (BBB) permeability of the PEI-MSNs in vitro and in vivo. Taking together the recent indications for the vulnerability of GSCs for lysosomal targeting and the lethality of the PEI-MSNs on GSCs cultured under stem cell culture conditions, the results enforce in vivo testing of the therapeutic impact of PEI-functionalized nanoparticles in faithful preclinical GB models.

Effect of manganese doping on the hyperthermic profile of ferrite nanoparticles using response surface methodology

Magnetic hyperthermia-based cancer therapy mediated by magnetic nanomaterials is a promising antitumoral nanotherapy, owning to its power to generate heat under the application of an alternating magnetic field. However, although the ultimate targets of these treatments, the heating potential and its relation with the magnetic behavior of the employed magnetic nanomaterials are rarely studied. Here we provide a bridge between the heating potential and magnetic properties such as anisotropy energy constant and saturation magnetization of the nano-magnets by simultaneous investigation of both hyperthermia and magnetism under a controlled set of variables given by response surface methodology. In the study, we have simultaneously investigated the effect of various synthesis parameters like cation ratio, reaction temperature and time on the magnetic response and heat generation of manganese-doped ferrite nanomaterials synthesized by a simple hydrothermal route. The optimum generation of heat and magnetization is obtained at a cationic ratio of approximately 42 at a temperature of 100 °C for a time period of 4 h. The optimized nanomaterial was then evaluated for in vitro magnetic hyperthermia application for cancer therapy against glioblastoma in terms of cell viability, effect on cellular cytoskeleton and morphological alterations. Furthermore, the correlation between the magnetic properties of the synthesized nanomaterial with its hyperthermia output was also established using K.V.M s variable where K, V and M s are the anisotropy energy constant, volume, and saturation magnetization of the nanomaterial respectively. It was found that the intensity of heat generation decreases with an increase in K.V.M s value, beyond 950 J emu g-1.

Monitoring of the choline/lipid ratio by 1H-MRS can be helpful for prediction and early detection of tumor response to nano-photo-thermal therapy

Nanotechnology-based photothermal therapy (NPTT) is a new emerging modality of cancer therapy. To have the right prediction and early detection of response to NPTT, it is necessary to get rapid feedback from a tumor treated by NPTT procedure and stay informed of what happens in the tumor site. We performed this study to find if proton magnetic resonance spectroscopy (1H-MRS) can be well responsive to such an imperative requirement. We considered various treatment groups including gold nanoparticles (AuNPs), laser, and the combination of AuNPs and laser (NPTT group). Therapeutic effects on CT26 colon tumor-bearing BALB/c mice were studied by looking at alterations that happened in 1H-MRS signals and tumor size after conducting treatment procedures. In MRS studies, the alterations of choline and lipid concentrations and their ratio were investigated. Having normalized the metabolite peak to water peak, we found a significant decrease in choline concentration post-NPTT (from (1.25 ± 0.05) × 10^-3 to (0.43 ± 0.04) × 10^-3), while the level of lipid concentration in the tumor was slightly increased (from (2.91 ± 0.23) × 10^-3 to (3.52 ± 0.31) × 10^-3). As a result, the choline/lipid ratio was significantly decreased post-NPTT (from 0.41 ± 0.11 to 0.11 ± 0.02). Such alterations appeared just 1 day after NPTT. Tumor shrinkage in all groups was studied and significant changes were significantly detectable on day 7 post-NPTT procedure. In conclusion, the study of choline/lipid ratio using 1H-MRS may help us estimate what happens in a tumor treated by the NPTT method. Such an in vivo assessment is interestingly feasible as soon as just 1 day post-NPTT. This would undoubtedly help the oncologists make a more precise decision about treatment planning strategies. Monitoring of the choline/lipid ratio by ¹H-MRS can be helpful for prediction and early detection of response to nano-photo-thermal therapy.

Lipid-Based Nanocarriers for The Treatment of Glioblastoma

Glioblastoma multiforme (GBM) is the most common and malignant neoplasia having origin in the brain. The current treatments involve surgery, radiotherapy, and chemotherapy, being complete surgical resection the best option for the patient survival chances. However, in those cases where a complete removal is not possible, radiation and chemotherapy are applied. Herein, the main challenges of chemotherapy, and how they can be overcome with the help of nanomedicine, are approached. Natural pathways to cross the blood-brain barrier (BBB) are detailed, and different in vivo studies where these pathways are mimicked functionalizing the nanomaterial surface are shown. Later, lipid-based nanocarriers, such as liposomes, solid lipid nanoparticles, and nanostructured lipid carriers, are presented. To finish, recent studies that have used lipid-based nanosystems carrying not only therapeutic agents, yet also magnetic nanoparticles, are described. Although the advantages of using these types of nanosystems are explained, including their biocompatibility, the possibility of modifying their surface to enhance the cell targeting, and their intrinsic ability of BBB crossing, it is important to mention that research in this field is still at its early stage, and extensive preclinical and clinical investigations are mandatory in the close future.

Nanotechnology and Nanocarrier-Based Drug Delivery as the Potential Therapeutic Strategy for Glioblastoma Multiforme: An Update

Simple Summary

Glioblastoma multiforme (GBM) are among the most lethal tumors. The highly invasive nature and presence of GBM stem cells, as well as the blood brain barrier (BBB) which limits chemotherapeutic drugs from entering the tumor mass, account for the high chance of treatment failure. Recent developments have found that nanoparticles can be conjugated to liposomes, dendrimers, metal irons, or polymeric micelles, which enhance the drug-loaded compounds to efficiently penetrate the BBB, thus offering new possibilities for overcoming GBM stem cell-mediated resistance to chemotherapy and radiation therapy. In addition, there have been new emerging strategies that use nanocarriers for successful GBM treatment in animal models. This review highlights the recent development of nanotechnology and nanocarrier-based drug delivery for treatment of GBMs, which may be a promising therapeutic strategy for this tumor entity.

Abstract

Glioblastoma multiforme (GBM) is the most common and malignant brain tumor with poor prognosis. The heterogeneous and aggressive nature of GBMs increases the difficulty of current standard treatment. The presence of GBM stem cells and the blood brain barrier (BBB) further contribute to the most important compromise of chemotherapy and radiation therapy. Current suggestions to optimize GBM patients’ outcomes favor controlled targeted delivery of chemotherapeutic agents to GBM cells through the BBB using nanoparticles and monoclonal antibodies. Nanotechnology and nanocarrier-based drug delivery have recently gained attention due to the characteristics of biosafety, sustained drug release, increased solubility, and enhanced drug bioactivity and BBB penetrability. In this review, we focused on recently developed nanoparticles and emerging strategies using nanocarriers for the treatment of GBMs. Current studies using nanoparticles or nanocarrier-based drug delivery system for treatment of GBMs in clinical trials, as well as the advantages and limitations, were also reviewed.

Tailoring functional nanostructured lipid carriers for glioblastoma treatment with enhanced permeability through in-vitro 3D BBB/BBTB models

The blood-brain barrier (BBB) and blood-brain tumour barrier (BBTB) pose a significant challenge to drug delivery to brain tumours, including aggressive glioblastoma (GB). The present study rationally designed functional nanostructured lipid carriers (NLC) to tailor their BBB penetrating properties with high encapsulation of CNS negative chemotherapeutic drug docetaxel (DTX). We investigated the effect of four liquid lipids, propylene glycol monolaurate (Lauroglycol® 90), Capryol® propylene glycol monocaprylate, caprylocaproylmacrogol-8-glycerides (Labrasol®) and polyoxyl-15-hydroxystearate (Kolliphor® HS15) individually and in combination to develop NLCs with effective permeation across in-vitro 3D BBB model without alteration in the integrity of the barrier. With desirable spherical shape as revealed by TEM and an average particle size of 123.3 ± 0.642 nm and zeta potential of -32 mV, DTX-NLCs demonstrated excellent stability for six months in its freeze-dried form. The confocal microscopy along with flow cytometry data revealed higher internalisation of DTX-NLCs in U87MG over SVG P12 cells. Micropinocytosis was observed to be one of the dominant pathways for internalisation in U87MG cells while clathrin-mediated pathway was more predominat in patient-derived glioblastoma cells. The NLCs readily penetrated the actively proliferating peripheral cells on the surface of the 3D tumour spheroids as compared to the necrotic core. The DTX-NLCs induced cell arrest through G2/M phase with a significant decrease in the mitochondrial reserve capacity of cells. The NLCs circumvented BBTB with high permeability followed by accumulation in glioblastoma cells with patient-derived cells displaying ~2.4-fold higher uptake in comparison to U87MG when studied in a 3D in-vitro model of BBTB/GB. We envisage this simple and industrially feasible technology as a potential candidate to be developed as GB nanomedicine.

Tearable and Fillable Composite Sponges Capable of Heat Generation and Drug Release in Response to Alternating Magnetic Field

Tearable and fillable implants are used to facilitate surgery. The use of implants that can generate heat and release a drug in response to an exogenous trigger, such as an alternating magnetic field (AMF), can facilitate on-demand combined thermal treatment and chemotherapy via remote operation. In this study, we fabricated tearable sponges composed of collagen, magnetite nanoparticles, and anticancer drugs. Crosslinking of the sponges by heating for 6 h completely suppressed undesirable drug release in saline at 37 °C but allowed drug release at 45 °C. The sponges generated heat immediately after AMF application and raised the cell culture medium temperature from 37 to 45 °C within 15 min. Heat generation was controlled by switching the AMF on and off. Furthermore, in response to heat generation, drug release from the sponges could be induced and moderated. Thus, remote-controlled heat generation and drug release were achieved by switching the AMF on and off. The sponges destroyed tumor cells when AMF was applied for 15 min but not when AMF was absent. The tearing and filling properties of the sponges may be useful for the surgical repair of bone and tissue defects. Moreover, these sponges, along with AMF application, can facilitate combined thermal therapy and chemotherapy.