Magnetic Nanodroplets for Enhanced Deep Penetration of Solid Tumors and Simultaneous Magnetothermal-Sensitized Immunotherapy against Tumor Proliferation and Metastasis

Ultrasound nanodroplets loaded with Siglec-G siRNA and Fe3O4 activate macrophages and enhance phagocytosis for immunotherapy of triple-negative breast cancer

BACKGROUND

The progression of triple-negative breast cancer is shaped by both tumor cells and the surrounding tumor microenvironment (TME). Within the TME, tumor-associated macrophages (TAMs) represent a significant cell population and have emerged as a primary target for cancer therapy. As antigen-presenting cells within the innate immune system, macrophages are pivotal in tumor immunotherapy through their phagocytic functions. Due to the highly dynamic and heterogeneous nature of TAMs, re-polarizing them to the anti-tumor M1 phenotype can amplify anti-tumor effects and help mitigate the immunosuppressive TME.

RESULTS

In this study, we designed and constructed an ultrasound-responsive targeted nanodrug delivery system to deliver Siglec-G siRNA and Fe3O4, with perfluorohexane (PFH) at the core and mannose modified on the surface (referred to as MPFS@NDs). Siglec-G siRNA blocks the CD24/Siglec-G mediated "don't eat me" phagocytosis inhibition pathway, activating macrophages, enhancing their phagocytic function, and improving antigen presentation, subsequently triggering anti-tumor immune responses. Fe3O4 repolarizes M2-TAMs to the anti-tumor M1 phenotype. Together, these components synergistically alleviate the immunosuppressive TME, and promote T cell activation, proliferation, and recruitment to tumor tissues, effectively inhibiting the growth of primary tumors and lung metastasis.

CONCLUSION

This work suggests that activating macrophages and enhancing phagocytosis to remodel the TME could be an effective strategy for macrophage-based triple-negative breast cancer immunotherapy.

Mild Magnetothermal Immunotherapy for Malignant Pleural Effusion

Malignant pleural effusion (MPE) is one of the most difficult complications of cancer to cure, usually indicating poor prognosis in late-stage cancer patients. Due to the presence of a large number of tumor-associated immune cells with the tumor promoting phenotype in MPE and pleural tumors, current clinical therapy offers limited effectiveness. Here, a mild magnetothermal regulation strategy is proposed based on a magnetic nanocatlytic nanoplatform ZCMF@PEG-AF (ZCMF-AF) constructed by surface-modifying anti-F4/80 antibody (AF) on ZnCoFe2O4@ZnMnFe2O4 magnetic nanoparticles (ZCMF) to target and polarize tumor-associated macrophages. Under alternating magnetic field-induced hyperthermia (41-42 °C), ZCMF-AF exhibits in situ nanocatalytic production of hydroxyl radicals via released iron ions under acidic cellular environment, which induces repolarization from the immunosuppressed M2 phenotype to the M1 phenotype. More importantly, the tumor cell damage induced by M1 macrophages and magnetic hyperthermia promote the maturation of dendritic cells, which subsequently awakens cytotoxic T lymphocytes to combat tumor cells. The integrated innate and adaptive immunity activations based on ZCMF-AF nano-immunomedicine through intrapleural administration elicit substantially regulated immune microenvironment of MPE and pleural tumors. Moreover, the interpleural magnetic nanoparticle-based immunotherapy effectively reduced the MPE volume and inhibited tumor growth in the pleural cavity, significantly prolonging the survival of the MPE-bearing mice.

Metal-based smart nanosystems in cancer immunotherapy

Metals are an emerging topic in cancer immunotherapy that have shown great potential in modulating cancer immunity cycle and promoting antitumor immunity by activating the intrinsic immunostimulatory mechanisms which have been identified in recent years. The main challenge of metal-assisted immunotherapy lies in the fact that the free metals as ion forms are easily cleared during circulation, and even cause systemic metal toxicity due to the off-target effects. With the rapid development of nanomedicine, metal-based smart nanosystems (MSNs) with unique controllable structure become one of the most promising delivery carriers to solve the issue, owing to their various endogenous/external stimuli-responsiveness to release free metal ions for metalloimmunotherapy. In this review, the state-of-the-art research progress in metal-related immunotherapy is comprehensively summarized. First, the mainstream mechanisms of MSNs-assisted immunotherapy will be delineated. The immunological effects of certain metals and categorization of MSNs with different characters and compositions are then provided, followed by the representative exemplar applications of MSNs in cancer treatment, and synergistic combination immunotherapy. Finally, we conclude this review with a summary of the remaining challenges associated with MSNs and provide the authors' perspective on their further advances.

Macrophage membrane-functionalized manganese dioxide nanomedicine for synergistic treatment of atherosclerosis by mitigating inflammatory storms and promoting cholesterol efflux

Atherosclerosis (AS) poses a significant threat to human life and health. However, conventional antiatherogenic medications exhibit insufficient targeting precision and restricted therapeutic effectiveness. Moreover, during the progression of AS, macrophages undergo polarization toward the proinflammatory M1 phenotype and generate reactive oxygen species (ROS) to accelerate the occurrence of inflammatory storms, and ingest excess lipids to form foam cells by inhibiting cholesterol efflux. In our study, we developed a macrophage membrane-functionalized hollow mesoporous manganese dioxide nanomedicine (Col@HMnO2-MM). This nanomedicine has the ability to evade immune cell phagocytosis, enables prolonged circulation within the body, targets the inflammatory site of AS for effective drug release, and alleviates the inflammatory storm at the AS site by eliminating ROS. Furthermore, Col@HMnO2-MM has the ability to generate oxygen autonomously by breaking down surplus hydrogen peroxide generated at the inflammatory AS site, thereby reducing the hypoxic microenvironment of the plaque by downregulating hypoxia-inducible factor (HIF-1α), which in turn enhances cholesterol efflux to inhibit foam cell formation. In an APOE-/- mouse model, Col@HMnO2-MM significantly reduced inflammatory factor levels, lipid storage, and plaque formation without significant long-term toxicity. In summary, this synergistic treatment significantly improved the effectiveness of nanomedicine and may offer a novel strategy for precise AS therapy.

Ultrasound-Responsive Nanodelivery System of GPC3-Targeting and Sonosensitizer for Visualized Hepatocellular Carcinoma Therapy

Purpose

The incidence of hepatocellular carcinoma (HCC) is continuously increasing, and the mortality rate remains high. Thus, more effective strategies are needed to improve the treatment of HCC.

Methods

In this study, we report the use of a visualized glypican-3 (GPC3)-targeting nanodelivery system (named GC-NBs) in combination with sonodynamic therapy (SDT) to enhance the therapeutic efficacy for treating HCC. The obtained nanodelivery system could actively target hepatocellular carcinoma cells and achieve ultrasound imaging through phase changes into nanobubbles under low-intensity ultrasound irradiation. Meanwhile, the released chlorine e6 (Ce6) after the nanobubbles collapse could lead to the generation of reactive oxygen species (ROS) under ultrasound irradiation to induce SDT.

Results

Both in vitro and in vivo experiments have shown that GC-NBs can accumulate in tumour areas and achieve sonodynamic antitumour therapy under the navigation action of glypican-3-antibody (GPC3-Ab). Furthermore, in vitro and in vivo experiments did not show significant biological toxicity of the nanodelivery system. Moreover, GC-NBs can be imaged with ultrasound, providing personalized treatment monitoring.

Conclusion

GC-NBs enable a visualized antitumour strategy from a targeted sonodynamic perspective by combining tumour-specific targeting and stimuli-responsive controlled release into a single system.

Ultrasound-Based Micro-/Nanosystems for Biomedical Applications

Due to the intrinsic non-invasive nature, cost-effectiveness, high safety, and real-time capabilities, besides diagnostic imaging, ultrasound as a typical mechanical wave has been extensively developed as a physical tool for versatile biomedical applications. Especially, the prosperity of nanotechnology and nanomedicine invigorates the landscape of ultrasound-based medicine. The unprecedented surge in research enthusiasm and dedicated efforts have led to a mass of multifunctional micro-/nanosystems being applied in ultrasound biomedicine, facilitating precise diagnosis, effective treatment, and personalized theranostics. The effective deployment of versatile ultrasound-based micro-/nanosystems in biomedical applications is rooted in a profound understanding of the relationship among composition, structure, property, bioactivity, application, and performance. In this comprehensive review, we elaborate on the general principles regarding the design, synthesis, functionalization, and optimization of ultrasound-based micro-/nanosystems for abundant biomedical applications. In particular, recent advancements in ultrasound-based micro-/nanosystems for diagnostic imaging are meticulously summarized. Furthermore, we systematically elucidate state-of-the-art studies concerning recent progress in ultrasound-based micro-/nanosystems for therapeutic applications targeting various pathological abnormalities including cancer, bacterial infection, brain diseases, cardiovascular diseases, and metabolic diseases. Finally, we conclude and provide an outlook on this research field with an in-depth discussion of the challenges faced and future developments for further extensive clinical translation and application.

A Paramagnetic Metal-Organic Framework Enhances Mild Magnetic Hyperthermia Therapy by Downregulating Heat Shock Proteins and Promoting Ferroptosis via Aggravation of Two-Way Regulated Redox Dyshomeostasis

Mild magnetic hyperthermia therapy (MMHT) holds great potential in treating deep-seated tumors, but its efficacy is impaired by the upregulation of heat shock proteins (HSPs) during the treatment process. Herein, Lac-FcMOF, a lactose derivative (Lac-NH2 ) modified paramagnetic metal-organic framework (FcMOF) with magnetic hyperthermia property and thermal stability, has been developed to enhance MMHT therapeutic efficacy. In vitro studies showed that Lac-FcMOF aggravates two-way regulated redox dyshomeostasis (RDH) via magnetothermal-accelerated ferricenium ions-mediated consumption of glutathione and ferrocene-catalyzed generation of ∙OH to induce oxidative damage and inhibit heat shock protein 70 (HSP70) synthesis, thus significantly enhancing the anti-cancer efficacy of MMHT. Aggravated RDH promotes glutathione peroxidase 4 inactivation and lipid peroxidation to promote ferroptosis, which further synergizes with MMHT. H22-tumor-bearing mice treated with Lac-FcMOF under alternating magnetic field (AMF) demonstrated a 90.4% inhibition of tumor growth. This work therefore provides a new strategy for the simple construction of a magnetic hyperthermia agent that enables efficient MMHT by downregulating HSPs and promoting ferroptosis through the aggravation of two-way regulated RDH.

Dual-responsive magnetic nanodroplets for controlled oxygen release via ultrasound and magnetic stimulation

Magnetic oxygen-loaded nanodroplets (MOLNDs) are a promising class of nanomaterials dually sensitive to ultrasound and magnetic fields, which can be employed as nanovectors for drug delivery applications, particularly in the field of hypoxic tissue treatment. Previous investigations were primarily focused on the application of these hybrid systems for hyperthermia treatment, exploiting magnetic nanoparticles for heat generation and nanodroplets as carriers and ultrasound contrast agents for treatment progress monitoring. This work places its emphasis on the prospect of obtaining an oxygen delivery system that can be activated by both ultrasound and magnetic fields. To achieve this goal, Fe3O4 nanoparticles were employed to decorate and induce the magnetic vaporization of OLNDs, allowing oxygen release. We present an optimized method for preparing MOLNDs by decorating nanodroplets made of diverse fluorocarbon cores and polymeric coatings. Furthermore, we performed a series of characterizations for better understanding how magnetic decoration can influence the physicochemical properties of OLNDs. Our comprehensive analysis demonstrates the efficacy of magnetic stimulation in promoting oxygen release compared to conventional ultrasound-based methods. We emphasize the critical role of selecting the appropriate fluorocarbon core and polymeric coating to optimize the decoration process and enhance the oxygen release performance of MOLNDs.

Dual Responsive Magnetic Drug Delivery Nanomicelles with Tumor Targeting for Enhanced Cancer Chemo/Magnetothermal Synergistic Therapy

Introduction

Stimulus-responsive nanocarrier systems are promising in cancer treatment. They improve drug stability and facilitate controlled drug release. However, single-responsive nanocarriers still face insufficient tumor targeting and low efficacy.

Methods

In this study, we synthesized folate-modified DSPE-PEOz nanomicelles with PEG chains and loaded them with magnetic iron particles and doxorubicin (DOX). Folic acid (FA) was employed as a ligand to target cancer cells actively. The nanomicelles are biocompatible and acid-sensitive drug carriers. Magnetic field-responsive nanoparticles enable moderately controlled magnetothermal therapy of tumors regardless of tumor location. The pH/magnetic field dual-responsive nanomicelles shed their PEG layer in response to tumor tissue acidity and react to magnetic fields through magnetothermal effects.

Results

In vitro and in vivo experiments demonstrated that the nanomicelles could efficiently target cancer cells, release drugs in response to pH changes, and enhance drug uptake through magnetothermal effects.

Discussion

The dual-responsive magnetic nanomicelles are expected to enhance the anti-cancer efficacy of chemo/magnetothermal synergistic therapy.

Conjugated Nanoparticles for Solid Tumor Theranostics: Unraveling the Interplay of Known and Unknown Factors

Cancer diagnoses have been increasing worldwide, and solid tumors are among the leading contributors to patient mortality, creating an enormous burden on the global healthcare system. Cancer is responsible for around 10.3 million deaths worldwide. Solid tumors are one of the most prevalent cancers observed in recent times. On the other hand, early diagnosis is a significant challenge that could save a person's life. Treatment with existing methods has pitfalls that limit the successful elimination of the disorder. Though nanoparticle-based imaging and therapeutics have shown a significant impact in healthcare, current methodologies for solid tumor treatment are insufficient. There are multiple complications associated with the diagnosis and management of solid tumors as well. Recently, surface-conjugated nanoparticles such as lipid nanoparticles, metallic nanoparticles, and quantum dots have shown positive results in solid tumor diagnostics and therapeutics in preclinical models. Other nanotheranostic material platforms such as plasmonic theranostics, magnetotheranostics, hybrid nanotheranostics, and graphene theranostics have also been explored. These nanoparticle theranostics ensure the appropriate targeting of tumors along with selective delivery of cargos (both imaging and therapeutic probes) without affecting the surrounding healthy tissues. Though they have multiple applications, nanoparticles still possess numerous limitations that need to be addressed in order to be fully utilized in the clinic. In this review, we outline the importance of materials and design strategies used to engineer nanoparticles in the treatment and diagnosis of solid tumors and how effectively each method overcomes the drawbacks of the current techniques. We also highlight the gaps in each material platform and how design considerations can address their limitations in future research directions.

Deep Tumor Penetration of CRISPR-Cas System for Photothermal-Sensitized Immunotherapy via Probiotics

Since central cells are more malignant and aggressive in solid tumors, improving penetration of therapeutic agents and activating immunity in tumor centers exhibit great potential in cancer therapies. Here, polydopamine-coated Escherichia coli Nissle 1917 (EcN) bearing CRISPR-Cas9 plasmid-loaded liposomes (Lipo-P) are applied for enhanced immunotherapy in deep tumors through activation of innate and adaptive immunity simultaneously. After accumulation in the tumor center through hypoxia targeting, Lipo-P could be detached under the reduction of reactive oxygen species (ROS)-responsive linkers, lowering the thermal resistance of cancer cells via Hsp90α depletion. Owing to that, heating induced by polydopamine upon near-infrared irradiation could achieve effective tumor ablation. Furthermore, mild photothermal therapy induces immunogenic cell death, as bacterial infections in tumor tissues trigger innate immunity. This bacteria-assisted approach provides a promising photothermal-sensitized immunotherapy in deep tumors.

Recent advances in magnetic nanocarriers for tumor treatment

Magnetic nanocarriers are nano-platforms that integrate multiple moieties based on magnetic nanoparticles for diagnostic and therapeutic purposes. In recent years, they have become an advanced platform for tumor treatment due to their wide application in magnetic resonance imaging (MRI), biocatalysis, magneto-thermal therapy (MHT), and photoresponsive therapy. Drugs loaded into magnetic nanocarriers can efficiently be directed to targeted areas by precisely reshaping their structural properties. Magnetic nanocarriers allow us to track the location of the therapeutic agent, continuously control the therapeutic process and eventually assess the efficacy of the treatment. They are typically used in synergistic therapeutic applications to achieve precise and effective tumor treatment. Here we review their latest applications in tumor treatment, including stimuli-responsive drug delivery, MHT, photoresponsive therapy, immunotherapy, gene therapy, and synergistic therapy. We consider reducing toxicity, improving antitumor efficacy, and the targeting accuracy of magnetic nanocarriers. The challenges of their clinical translation and prospects in cancer therapy are also discussed.