A tumor cell exosome-mimicking multifunctional nanozyme for targeted breast cancer radiotherapy

Multifunctional nanozymes: Promising applications in clinical diagnosis and cancer treatment

Cancer remains one of the greatest challenges in modern medicine. Traditional chemotherapy drugs often cause severe side effects, including nausea, vomiting, diarrhea, neurotoxicity, liver damage, and nephrotoxicity. In addition to these adverse effects, high recurrence and metastasis rates following treatment pose significant challenges for clinicians. There is an urgent need for novel therapeutic strategies to improve cancer treatment outcomes. In this context, nanozymes-artificial enzyme mimetics-have attracted considerable attention due to their unique advantages, including potent tumor-killing effects, enhanced biocompatibility, and reduced toxicity. Notably, nanozymes can dynamically monitor tumors through imaging and tracing. The multifunctional nanozyme (MN) is a promising research focus, integrating multiple catalytic activities, signal enhancement, sensing capabilities, and diverse modifications within a single nanozyme system. MNs can selectively target tumor regions, facilitating synergistic effects with other cancer therapies while enabling real-time imaging and tumor tracking. In this review, we first categorize MNs based on their composition and structural characteristics. We then discuss the primary mechanisms by which MNs exert their anticancer effects. Additionally, we review three types of MN biosensors and four MN-based therapeutic approaches applied in cancer treatment. Finally, we highlight the current challenges in MN research and provide an outlook on future developments in this field.

Biomimetic peroxisome targets myocardial injury and promotes heart repair and regeneration

Heart ischemic injury predominately causes mitochondrial dysfunction, leading to the accumulation of ROS and lactate. The ROS-associated DNA damage response (DDR) contributes to myocardial cell cycle arrest and the inhibition of proliferation, while lactate accumulation is often accompanied by a high risk of acute death. In this study, to restore myocardial metabolism and regenerate the heart, we established a biomimetic peroxisome by loading the Mn3O4 nanozyme into mesenchymal stem cell-derived extracellular vesicles (MSC-EV (Mn@EV)). This setup mimics the peroxidases of peroxisome to catalyze ROS, and inhibit DDR. Next, the Mn@EV was immobilized with lactate oxidase (LOX) after encompassed platelet membrane to obtain biomimetic peroxisome (Mn@LPEV). This mimics the substrate-oxidizing function to detoxify lactate and prevent death. Supported by its biomimetic and lactate-response delivery system, our biomimetic peroxisome effectively targeted deep tissues in the hearts of I/R mice, achieving a 4-fold increase in targeting compared with control vesicles. It maintained myocardial redox homeostasis by scavenging ROS and lactate, inhibiting DDR pathway, promoting myocardial regeneration, reducing acute mortality and fibrosis remodeling, accelerating immunomodulation and angiogenesis, and significantly protecting heart function.

Nanozyme-mediated glutathione depletion for enhanced ROS-based cancer therapies: a comprehensive review

Nanozymes can improve reactive oxygen species (ROS)-based cancer therapies by targeting cancer cells' antioxidant defense mechanisms, particularly glutathione (GSH) depletion, to overcome ROS-resistant cancer cells. Nanozymes, innovative enzyme-mimetic nanomaterials, can generate ROS, alter the tumor microenvironment (TME), and synergize with photodynamic therapy (PDT), chemodynamic therapy (CDT), radiotherapy, and immunotherapy. This review shows how nanozymes catalyze ROS generation, selectively deplete GSH, and target cancer elimination, offering clear advantages over standard therapies. Nanozymes selectively target cancer cells' antioxidant defenses to improve PDT, CDT, and radiation therapies. To maximize nanozyme-based cancer treatment efficacy, biodistribution, biocompatibility, and tumor heterogeneity must be assessed. To improve cancer treatment, multifunctional, stimuli-responsive nanozymes and synergistic combination drugs should be developed.

Rational Design of Nanozymes for Engineered Cascade Catalytic Cancer Therapy

Nanozymes have shown significant potential in cancer catalytic therapy by strategically catalyzing tumor-associated substances and metabolites into toxic reactive oxygen species (ROS) in situ, thereby inducing oxidative stress and promoting cancer cell death. However, within the complex tumor microenvironment (TME), the rational design of nanozymes and factors like activity, reaction substrates, and the TME itself significantly influence the efficiency of ROS generation. To address these limitations, recent research has focused on exploring the factors that affect activity and developing nanozyme-based cascade catalytic systems, which can trigger two or more cascade catalytic processes within tumors, thereby producing more therapeutic substances and achieving efficient and stable cancer therapy with minimal side effects. This area has shown remarkable progress. This Perspective provides a comprehensive overview of nanozymes, covering their classification and fundamentals. The regulation of nanozyme activity and efficient strategies of rational design are discussed in detail. Furthermore, representative paradigms for the successful construction of cascade catalytic systems for cancer treatment are summarized with a focus on revealing the underlying catalytic mechanisms. Finally, we address the current challenges and future prospects for the development of nanozyme-based cascade catalytic systems in biomedical applications.

Nanozymes-Mediated Cascade Reaction System for Tumor-Specific Diagnosis and Targeted Therapy

Cascade reactions are described as efficient and versatile tools, and organized catalytic cascades can significantly improve the efficiency of chemical interworking between nanozymes. They have attracted great interest in many fields such as chromogenic detection, biosensing, tumor diagnosis, and therapy. However, how to selectively kill tumor cells by enzymatic reactions without harming normal cells, as well as exploring two or more enzyme-engineered nanoreactors for cascading catalytic reactions, remain great challenges in the field of targeted and specific cancer diagnostics and therapy. The latest research advances in nanozyme-catalyzed cascade processes for cancer diagnosis and therapy are described in this article. Here, various sensing strategies are summarized, for tumor-specific diagnostics. Targeting mechanisms for tumor treatment using cascade nanozymes are classified and analyzed, "elements" and "dimensions" of cascade nanozymes, types, designs of structure, and assembly modes of highly active and specific cascade nanozymes, as well as a variety of new strategies of tumor targeting based on the cascade reaction of nanozymes. Finally, the integrated application of the cascade nanozymes systems in tumor-targeted and specific diagnostic therapy is summarized, which will lay the foundation for the design of more rational, efficient, and specific tumor diagnostic and therapeutic modalities in the future.

Biomimetic copper-doped polypyrrole nanoparticles induce glutamine metabolism inhibition to enhance breast cancer cuproptosis and immunotherapy

Cuproptosis, a newly discovered mechanism of inducing tumor cell death, primarily relies on the intracellular accumulation of copper ions. The utilization of Cu-based nanomaterials to induce cuproptosis holds promising prospects in future biomedical applications. However, the presence of high levels of glutathione (GSH) within tumor cells hinders the efficacy of cuproptosis. In this study, we have developed a BPTES-loaded biomimetic Cu-doped polypyrrole nanoparticles (CuP) nanosystem (PCB) for enhanced cuproptosis and immune modulation. PCB comprises an internal BPTES and CuP core and an external platelet membrane (PM) that facilitates active targeting to tumor sites following intravenous administration. Subsequently, PCB effectively suppresses glutaminase (GLS1) activity, thereby reducing GSH content. Moreover, CuP catalyze intracellular H2O2, amplifying oxidative stress while simultaneously inducing dihydrolipoyl transacetylase (DLAT) oligomerization through released Cu2+, resulting in cuproptosis. PCB not only inhibits primary tumors but also exhibits inhibitory effects on abscopal tumors. This work represents the first instance where GLS inhibition has been employed to enhance cuproptosis and immunotherapy. It also provides valuable insights into further investigations on cuproptosis.

Extracellular vesicles in nanomedicine and regenerative medicine: A review over the last decade

Small extracellular vesicles (sEVs) are known to be secreted by a vast majority of cells. These sEVs, specifically exosomes, induce specific cell-to-cell interactions and can activate signaling pathways in recipient cells through fusion or interaction. These nanovesicles possess several desirable properties, making them ideal for regenerative medicine and nanomedicine applications. These properties include exceptional stability, biocompatibility, wide biodistribution, and minimal immunogenicity. However, the practical utilization of sEVs, particularly in clinical settings and at a large scale, is hindered by the expensive procedures required for their isolation, limited circulation lifetime, and suboptimal targeting capacity. Despite these challenges, sEVs have demonstrated a remarkable ability to accommodate various cargoes and have found extensive applications in the biomedical sciences. To overcome the limitations of sEVs and broaden their potential applications, researchers should strive to deepen their understanding of current isolation, loading, and characterization techniques. Additionally, acquiring fundamental knowledge about sEVs origins and employing state-of-the-art methodologies in nanomedicine and regenerative medicine can expand the sEVs research scope. This review provides a comprehensive overview of state-of-the-art exosome-based strategies in diverse nanomedicine domains, encompassing cancer therapy, immunotherapy, and biomarker applications. Furthermore, we emphasize the immense potential of exosomes in regenerative medicine.

Transition-Metal-Based Nanozymes: Synthesis, Mechanisms of Therapeutic Action, and Applications in Cancer Treatment

Cancer, as one of the leading causes of death worldwide, drives the advancement of cutting-edge technologies for cancer treatment. Transition-metal-based nanozymes emerge as promising therapeutic nanodrugs that provide a reference for cancer therapy. In this review, we present recent breakthrough nanozymes for cancer treatment. First, we comprehensively outline the preparation strategies involved in creating transition-metal-based nanozymes, including hydrothermal method, solvothermal method, chemical reduction method, biomimetic mineralization method, and sol-gel method. Subsequently, we elucidate the catalytic mechanisms (catalase (CAT)-like activities), peroxidase (POD)-like activities), oxidase (OXD)-like activities) and superoxide dismutase (SOD)-like activities) of transition-metal-based nanozymes along with their activity regulation strategies such as morphology control, size manipulation, modulation, composition adjustment and surface modification under environmental stimulation. Furthermore, we elaborate on the diverse applications of transition-metal-based nanozymes in anticancer therapies encompassing radiotherapy (RT), chemodynamic therapy (CDT), photodynamic therapy (PDT), photothermal therapy (PTT), sonodynamic therapy (SDT), immunotherapy, and synergistic therapy. Finally, the challenges faced by transition-metal-based nanozymes are discussed alongside future research directions. The purpose of this review is to offer scientific guidance that will enhance the clinical applications of nanozymes based on transition metals.

Multifunctional AuPt Nanoparticles for Synergistic Photothermal and Radiation Therapy

Background

Photothermal therapy (PTT) has gained considerable interest as an emerging modality for cancer treatment in recent years. Radiation therapy (RT) has been widely used in the clinic as a traditional treatment method. However, RT and PTT treatments are limited by side effects and penetration depth, respectively. In addition, hypoxia within the tumor can lead to increased resistance to treatment.

Methods

We synthesized multiple sizes of AuPt by modulating the reaction conditions. The smallest size of AuPt was selected and modified with folic acid (FA) for PTT and RT synergy therapy. Various methods including transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FITR) are used to determine the structure and composition of AuPt-FA (AF). In addition, we researched the photothermal properties of AF with IR cameras and infrared lasers. Flow cytometry, colony formation assays, CCK8, and fluorescent staining for probing the treatment effect in vitro. Also, we explored the targeting of AF by TEM and In Vivo Imaging Systems (IVIS). In vivo experiments, we record changes in tumor volume and weight as well as staining of tumor sections (ROS, Ki67, and hematoxylin and eosin).

Results

The AuPt with particle size of 16 nm endows it with remarkably high photothermal conversion efficiency (46.84%) and catalase activity compared to other sizes of AuPt (30 nm and 100 nm). AF alleviates hypoxia in the tumor microenvironment, leading to the production of more reactive oxygen species (ROS) during the treatment. In addition, the therapeutic effect was significantly enhanced by combining RT and PTT, with an apoptosis rate of 81.1% in vitro and an in vivo tumor volume reduction rate of 94.0% in vivo.

Conclusion

These results demonstrate that AF potentiates the synergistic effect of PTT and RT and has the potential for clinical translation.