Dual catalytic cascaded nanoplatform for photo/chemodynamic/starvation synergistic therapy

Reduced graphene oxide quantum dots/manganese dioxide/glucose oxidase nanoparticles for cascade catalytic cancer treatment in multimodal starvation therapy-augmented chemodynamic/photothermal therapy

Combination cancer therapy can boost the overall treatment efficacy using functional nanomaterials that specifically target cancer cells. Furthermore, the treatment outcome can be improved by focusing on specific characteristics in the tumor microenvironment (TME). In this study, tumor-targeting multifunctional nanoparticles were constructed from reduced graphene oxide quantum dots (rGOQD), manganese dioxide (MnO2), glucose oxidase (GOx), and cell-penetrating peptide (CPP). The rGOQD/MnO2/GOx/CPP nanoparticles can treat tumors by strengthening chemodynamic/photothermal therapy (CDT/PTT) with starvation therapy (ST). The MnO2 reacts with high concentrations of endogenous H2O2 in an acidic TME to produce reactive oxygen species (ROSs) from Mn2+. The highly cytotoxic hydroxyl radical (•OH) kills cancer cells and initiates CDT. The MnO2 can also consume the •OH scavenger glutathione (GSH) in cancer cells and eliminate their antioxidant defense. The GOx oxidizes glucose to cause cancer cell glucose starvation for ST, which produces H2O2 to boost the efficacy of CDT. By consuming glucose, ST mediated by GOx leads to reduced ATP production in the glycolysis pathway. This downregulates the expression of ATP-dependent heat shock proteins that provide cancer cell thermal resistance when the photothermal agent rGOQD is irradiated with near-infrared (NIR) light for PTT. Therefore, we prepare different rGOQD-based nanoparticles and characterize their physicochemical and biological properties. The nanoparticles were studied in vitro against U87 glioblastoma cells for targeted cancer therapy. Using nude mice bearing subcutaneous U87 tumors, the in vivo study indicates rGOQD/MnO2/GOx/CPP plus NIR irradiation can substantially inhibit the tumor growth rate without causing adverse effects from CPP-mediated trimodal ST/CDT/PTT.

Multidimensional applications of prussian blue-based nanoparticles in cancer immunotherapy

Immunotherapy holds notable progress in the treatment of cancer. However, the clinical therapeutic effect remains a significant challenge due to immune-related side effects, poor immunogenicity, and immunosuppressive microenvironment. Nanoparticles have emerged as a revolutionary tool to surmount these obstacles and amplify the potency of immunotherapeutic agents. Prussian blue nanoparticles (PBNPs) exhibit multi-dimensional immune function in cancer immunotherapy, including acting as a nanocarrier to deliver immunotherapeutic agents, as a photothermal agent to improve the efficacy of immunotherapy through photothermal therapy, as a nanozyme to regulate tumor microenvironment, and as an iron donor to induce immune events related to ferroptosis and tumor-associated macrophages polarization. This review focuses on the advances and applications of PBNPs in cancer immunotherapy. First, the biomedical functions of PBNPs are introduced. Then, based on the immune function of PBNPs, we systematically reviewed the multidimensional application of PBNPs in cancer immunotherapy. Finally, the challenges and future developments of PBNPs-based cancer immunotherapy are highlighted.

Advances and perspectives in phototherapy-based combination therapy for cancer treatment

Phototherapy, including photothermal therapy (PTT) and photodynamic therapy (PDT), has the advantages of spatiotemporal selectivity, non-invasiveness, and negligible drug resistance. Phototherapy has been approved for treating superficial epidermal tumors. However, its therapeutic efficacy is limited by the hypoxic tumor microenvironment and the highly expressed heat shock protein. Moreover, poor tissue penetration and focused irradiation laser region in phototherapy make treating deep tissues and metastatic tumors challenging. Combination therapy strategies, which integrate the advantages of each treatment and overcome their disadvantages, can significantly improve the therapeutic efficacy. Recently, many combination therapy strategies have been reported. Our study summarizes the strategies used for combining phototherapy with other cancer treatments such as chemotherapy, immunotherapy, sonodynamic therapy, gas therapy, starvation therapy, and chemodynamic therapy. Some research cases were selected to analyze the combination therapy effect, delivery platform feature, and synergetic anticancer mechanisms. Moreover, additional research cases are summarized in the tables. This review provides strong evidence that phototherapy-based combination strategies can enhance the anticancer effect compared with phototherapy alone. Additionally, the challenges and future perspectives associated with these combinational therapies are discussed.

Anti-Colon Cancer Activity of Copper-Doped Folate Carbon Dots/MnO2 Complexes Based on Oxygenation and Immune-Enhancing Effects

In clinical practice, the treatment of colon cancer is faced with the dilemma of metastasis and recurrence, which is related to immunosuppression and hypoxia. Immune checkpoint blockade (ICB) is a negative regulatory pathway of immunity. Immune checkpoint blockade (ICB) is an important immunotherapy method. However, inadequate immunogenicity reduces the overall response rate of ICB. In this study, a tumor microenvironment-responsive nanomedicine (Cu-FACD@MnO2@FA) was prepared to increase host immune response and increase intracellular oxygen levels. Cu-FACD@MnO2@FA preferentially enriched at the tumor site, combined with the immune checkpoint inhibitor alpha PD-L1, induced sufficient immunogenicity to treat colon cancer. Immunofluorescence detection of tumor cells and tissues showed that the expression of hypoxa-inducing factor 1α was significantly down-regulated after treatment and the expression of immunoactivity-related proteins was significantly changed. In vivo treatment in a bilateral tumor mouse model showed complete ablation of the primary tumor and efficient inhibition of the distal tumor. In this study, for the first time, the oxygenation effects of MnO2-coated Cu-doped carbon dots and chemodynamic therapy and a strategy of combining with immuno-blocking therapy were used for treating colon cancer.

Manganese-based nanomaterials in diagnostics and chemodynamic therapy of cancers: new development

In the realm of cancer treatment, traditional modalities like radiotherapy and chemotherapy have achieved certain advancements but continue to grapple with challenges including harm to healthy tissues, resistance to treatment, and adverse drug reactions. The swift progress in nanotechnology recently has opened avenues for investigating innovative approaches to cancer therapy. Especially, chemodynamic therapy (CDT) utilizing metal nanomaterials stands out as an effective cancer treatment choice owing to its minimal side effects and independence from external energy sources. Transition metals like manganese are capable of exerting anti-tumor effects through a Fenton-like mechanism, with their distinctive magnetic properties playing a crucial role as contrast agents in tumor diagnosis and treatment. Against this backdrop, this review emphasizes the recent five-year advancements in the application of manganese (Mn) metal ions within nanomaterials, particularly highlighting their unique capabilities in catalyzing CDT and enhancing MRI imaging. Initially, we delineate the biomedical properties of manganese, followed by an integrated discussion on the utilization of manganese-based nanomaterials in CDT alongside multimodal therapies, and delve into the application and future outlook of manganese-based nanomaterial-mediated MRI imaging techniques in cancer therapy. By this means, the objective is to furnish novel viewpoints and possibilities for the research and development in future cancer therapies.

Cancer diagnosis and treatment platform based on manganese-based nanomaterials

Cancer is a leading cause of death worldwide, and the development of new diagnostic and treatment methods is crucial. Manganese-based nanomaterials (MnNMs) have emerged as a focal point in the field of cancer diagnosis and treatment due to their multifunctional properties. These nanomaterials have been extensively explored as contrast agents for various imaging technologies such as magnetic resonance imaging (MRI), photoacoustic imaging (PAI), and near-infrared fluorescence imaging (NIR-FL). The use of these nanomaterials has significantly enhanced the contrast for precise tumor detection and localization. Moreover, MnNMs have shown responsiveness to the tumor microenvironment (TME), enabling innovative approaches to cancer treatment. This review provides an overview of the latest developments of MnNMs and their potential applications in tumor diagnosis and therapy. Finally, potential challenges and prospects of MnNMs in clinical applications are discussed. We believe that this review would serve as a valuable resource for guiding further research on the application of manganese nanomaterials in cancer diagnosis and treatment, addressing the current limitations, and proposing future research directions.

Recent advances in glucose oxidase-based nanocarriers for tumor targeting therapy

Glucose oxidase (GOx) can specifically catalyze the conversion of β-d-glucose into gluconic acid and hydrogen peroxide (H2O2) in the presence of oxygen, making it promising for tumor starvation therapy and oxidative therapy. However, GOx's immunogenicity, poor in vivo stability, short half-life, and potential systemic toxicity, limit its application in cancer therapy. Nanocarriers are capable of improving the pharmacological properties of therapeutic drugs (e.g. stability, circulating half-life, and tumor accumulation) and lower toxicity, hence resolving GOx issues and enhancing its efficacy. Although the application of targeted nanocarriers based on GOx has recently flourished, this field has not yet been reviewed and evaluated. Herein, we initially examined the mechanism of GOx-based nanocarriers for enhanced tumor therapy. Also, we present a comprehensive and up-to-date review that highlights GOx-based nanocarriers for tumor targeting therapy. This review expands on GOx-based nano-targeted combination therapies from both passive and active targeting perspectives, meanwhile, active targeting is further classified into ligand-mediated targeting and physical-mediated targeting. Furthermore, this review also emphasizes the present challenges and promising advancements.

Role and Application of Biocatalysts in Cancer Drug Discovery

A biocatalyst is an enzyme that speeds up or slows down the rate at which a chemical reaction occurs and speeds up certain processes by 108 times. It is used as an anticancer agent because it targets drug activation inside the tumor microenvironment while limiting damage to healthy cells. Biocatalysts have been used for the synthesis of different heterocyclic compounds and is also used in the nano drug delivery systems. The use of nano-biocatalysts for tumor-targeted delivery not only aids in tumor invasion, angiogenesis, and mutagenesis, but also provides information on the expression and activity of many markers related to the microenvironment. Iosmapinol, moclobemide, cinepazide, lysine dioxygenase, epothilone, 1-homophenylalanine, and many more are only some of the anticancer medicines that have been synthesised using biocatalysts. In this review, we have highlighted the application of biocatalysts in cancer therapies as well as the use of biocatalysts in the synthesis of drugs and drug-delivery systems in the tumor microenvironment.

Biomolecule-based Stimuli-responsive Nanohybrids for Tumor-specific and Cascade-enhanced Synergistic Therapy

Poor tumor specificity is one of the key obstacles for clinical applications of nanotheranostic agents, consequently leading to serious side effects and unsatisfactory therapeutic efficacy. Herein, biomolecule-based nanohybrids (named as Hb-PDA-GOx) with multiple stimuli-responsiveness were designed and fabricated to enhance tumor-specific therapy. The nanohybrids embodied two proteins, i.e., hemoglobin (Hb) and glucose oxidase (GOx), which exhibited cascade catalytic activity selectively within the tumor microenvironment (TME). Specifically, GOx catalyzes the overexpressed glucose into gluconic acid and hydrogen peroxide (H₂O₂), which not only initiated starvation therapy (ST) through cutting off the nutrition supply for carcinoma cells, but also provided H₂O₂ for sequential Fenton reaction induced by Hb that generating biotoxic hydroxyl radicals (•OH) for chemodynamic therapy (CDT). Moreover, localized heat generation from polydopamine (PDA) in the nanohybrids can implement photothermal therapy (PTT) and reinforce the CDT efficacy. Excitingly, effective eradication of solid tumors and significant suppression of metastatic tumors growth were achieved by utilizing Hb-PDA-GOx as a versatile theranostic agent. All these results had been verified by in vitro and/or in vivo experiments. In light of the superior anticancer effects and insignificant systemic toxicity, the as-fabricated biomolecule-based nanohybrids could be employed as a promising agent for tumor-specific therapy. More importantly, the high biocompatibility and biodegradability of the selected biomolecules would facilitate subsequent clinical translation. STATEMENT OF SIGNIFICANCE: 1) A facile one-pot synthesis strategy was proposed to fabricate biomolecule-based tumor theranostic agent with high biocompatibility and biodegradability, which would facilitate subsequent clinical translation; 2) The as-developed theranostic agent was endowed with multiple stimuli-responsiveness for achieving tumor-specific and cascade-enhanced synergistic therapy; 3) The in vivo experiments demonstrated that the as-developed theranostic agent can not only effectively eradicate solid tumors, but also significantly suppress metastatic tumors growth.

Glucose Metabolism Intervention-Facilitated Nanomedicine Therapy

Ordinarily, cancer cells possess features of abnormally increased nutrient intake and metabolic pathways. The disorder of glucose metabolism is the most important among them. Therefore, starvation therapy targeting glucose metabolism specifically, which results in metabolic disorders, restricted synthesis, and inhibition of tumor growth, has been developed for cancer therapy. However, issues such as inadequate targeting effectiveness and drug tolerance impede their clinical transformation. In recent years, nanomaterial-assisted starvation treatment has made significant progress in addressing these challenges, whether as a monotherapy or in combination with other medications. Herein, representative researches on the construction of nanosystems conducting starvation therapy are introduced. Elaborate designs and interactions between different treatment mechanisms are meticulously mentioned. Not only are traditional treatments based on glucose oxidase involved, but also newly sprung small molecule agents targeting glucose metabolism. The obstacles and potential for advancing these anticancer therapies were also highlighted in this review.

Chemodynamic Therapy via Fenton and Fenton-Like Nanomaterials: Strategies and Recent Advances

Chemodynamic therapy (CDT), a novel cancer therapeutic strategy defined as the treatment using Fenton or Fenton-like reaction to produce •OH in the tumor region, was first proposed by Bu, Shi, and co-workers in 2016. Recently, with the rapid development of Fenton and Fenton-like nanomaterials, CDT has attracted tremendous attention because of its unique advantages: 1) It is tumor-selective with low side effects; 2) the CDT process does not depend on external field stimulation; 3) it can modulate the hypoxic and immunosuppressive tumor microenvironment; 4) the treatment cost of CDT is low. In addition to the Fe-involved CDT strategies, the Fenton-like reaction-mediated CDT strategies have also been proposed, which are based on many other metal elements including copper, manganese, cobalt, titanium, vanadium, palladium, silver, molybdenum, ruthenium, tungsten, cerium, and zinc. Moreover, CDT has been combined with other therapies like chemotherapy, radiotherapy, phototherapy, sonodynamic therapy, and immunotherapy for achieving enhanced anticancer effects. Besides, there have also been studies that extend the application of CDT to the antibacterial field. This review introduces the latest advancements in the nanomaterials-involved CDT from 2018 to the present and proposes the current limitations as well as future research directions in the related field.

Tumor microenvironment responsive self-cascade catalysis for synergistic chemo/chemodynamic therapy by multifunctional biomimetic nanozymes

Chemodynamic therapy (CDT) is an emerging approach to treat cancer based on the tumor microenvironment (TME), but its limited content of endogenous hydrogen peroxide (H₂O₂) weakens the anticancer effects. Herein, a multifunctional biomimetic nanozyme (Se@SiO₂-Mn@Au/DOX, named as SSMA/DOX) is fabricated, which undergoes TME responsive self-cascade catalysis to facilitate MRI guided enhanced chemo/chemodynamic therapy. The SSMA/DOX nanocomposites (NCs) responsively degrade in acidic conditions of tumor to release Se, DOX, Au and Mn²⁺. Mn²⁺ not only enables MRI to guided therapy, but also catalyzes the endogenous H₂O₂ into hydroxyl radical (˙OH) for CDT. In addition, the Au NPs continuously catalyze glucose to generate H₂O₂, enhancing CDT by supplementing a sufficiently reactive material and cutting off the energy supply of the tumor by consuming glucose. Simultaneously, Se enhances the chemotherapy of doxorubicin hydrochloride (DOX) and CDT by upregulating ROS in the tumor cells, achieving remarkable inhibition effect towards tumor. Moreover, SSMA/DOX NCs have good biocompatibility and degradability, which avoid long-term toxicity and side effects. Overall, the degradable SSMA/DOX NCs provide an innovative strategy for tumor microenvironment responsive self-cascade catalysis to enhance tumor therapy.

Synthesis of manganese-oxide and palladium nanoparticles co-decorated polypyrrole/graphene oxide (MnO2@Pd@PPy/GO) nanocomposites for anti-cancer treatment

Design and fabrication of novel multifunctional nanomaterials as novel “theranostic nanoagents”with high efficiency and low side effects is important for cancer treatment. Herein, we synthesized manganese-oxide and palladium nanoparticle-co-decorated polypyrrole/graphene oxide (MnO₂@Pd@PPy/GO) nanocomposites, which could be used as a novel “theranostic nanoagent” for cancer treatment. Various spectroscopic and microscopic characterizations of the synthesized MnO₂@Pd@PPy/GO nanocomposites suggest that the nanocomposites are assembled sequentially by graphene oxide, polypyrrole, palladium nanoparticles and manganese-oxide nanoplates. Further research revealed that the nanocomposites had excellent photothermal conversion performance (reached near 50 °C after 10 min of irradiation), pH responsive enzymatic-like catalytic activity and enhanced magnetic resonance imaging (MRI) performance (r₁ = 7.74 mM⁻¹ s⁻¹ at pH 5.0 and glutathione (GSH)). Cell experiments also testified that combined cancer treatment (the viability of cancer cells is 30%) with photothermal therapy (PTT, the viability of cancer cells is 91% only with irradiation) and chemodynamic therapy (CDT, the viability of cancer cells is 74.7% only with nanocomposites) guided by MRI was achieved when the as-prepared nanocomposites were employed as theranostic nanoagents. This work could provide some new ideas for the controllable synthesis and application of multicomponent nanomaterials.

Manganese-oxide and palladium nanoparticle-co-decorated polypyrrole/graphene oxide (MnO₂@Pd@PPy/GO) nanoenzyme composites were synthesized, and could be as a novel “theranostic nanoagent” for cancer treatment due to excellent performance.

Mitochondria-targeted accumulation of oxygen-irrelevant free radicals for enhanced synergistic low-temperature photothermal and thermodynamic therapy

BACKGROUND

Although lower temperature (< 45 °C) photothermal therapy (LPTT) have attracted enormous attention in cancer therapy, the therapeutic effect is still unsatisfying when applying LPTT alone. Therefore, combining with other therapies is urgently needed to improve the therapeutic effect of LPTT. Recently reported oxygen-irrelevant free radicals based thermodynamic therapy (TDT) exhibit promising potential for hypoxic tumor treatment. However, overexpression of glutathione (GSH) in cancer cells would potently scavenge the free radicals before their arrival to the specific site and dramatically diminish the therapeutic efficacy.

METHODS AND RESULTS

In this work, a core-shell nanoplatform with an appropriate size composed of arginine-glycine-aspartate (RGD) functioned polydopamine (PDA) as a shell and a triphenylphosphonium (TPP) modified hollow mesoporous manganese dioxide (H-mMnO2) as a core was designed and fabricated for the first time. This nanostructure endows a size-controllable hollow cavity mMnO2 and thickness-tunable PDA layers, which effectively prevented the pre-matured release of encapsulated azo initiator 2,2'-azobis[2-(2-imidazolin-2-yl) propane] dihydrochloride (AIBI) and revealed pH/NIR dual-responsive release performance. With the mitochondria-targeting ability of TPP, the smart nanocomposites (AIBI@H-mMnO2-TPP@PDA-RGD, AHTPR) could efficiently induce mitochondrial associated apoptosis in cancer cells at relatively low temperatures (< 45 °C) via selectively releasing oxygen-irrelevant free radicals in mitochondria and facilitating the depletion of intracellular GSH, exhibiting the advantages of mitochondria-targeted LPTT/TDT. More importantly, remarkable inhibition of tumor growth was observed in a subcutaneous xenograft model of osteosarcoma (OS) with negligible side effects.

CONCLUSIONS

The synergistic therapy efficacy was confirmed by effectively inducing cancer cell death in vitro and completely eradicating the tumors in vivo. Additionally, the excellent biosafety and biocompatibility of the nanoplatforms were confirmed both in vitro and in vivo. Taken together, the current study provides a novel paradigm toward oxygen-independent free-radical-based cancer therapy, especially for the treatment of hypoxic solid tumors.

Glutathione-triggered nanoplatform for chemodynamic/metal-ion therapy

The integration of metal-ion therapy and hydroxyl radical (˙OH)-mediated chemodynamic therapy (CDT) holds great potential for anticancer treatment with high specificity and efficiency. Herein, Ag nanoparticles (Ag NPs) were enveloped with Cu²⁺-based metal-organic frameworks (MOFs) and further decorated with hyaluronic acid (HA) to construct a glutathione (GSH)-activated nanoplatform (Ag@HKU-HA) for specific chemodynamic/metal-ion therapy. The obtained nanoplatform could avoid the premature leakage of Ag in circulation, but realize the release of Ag at the tumor site owing to the degradation of external MOFs triggered by Cu²⁺-reduced glutathione. The generated Cu⁺ could catalyze endogenous H₂O₂ to the highly toxic ˙OH by a Fenton-like reaction. Meanwhile, Ag NPs were oxidized to toxic Ag ions in the tumor environment. As expect, the effect of CDT combined with metal-ion therapy exhibited an excellent inhibition of tumor cells growth. Therefore, this nanoplatform may provide a promising strategy for on-demand site-specific cancer combination treatment.

Synergistic anticancer theragnostic study of a core-shell structured galvanic cell

The chemodynamic therapy (CDT) effect is restricted by the neutral pH environment in the tumor, also, the protein corona formed on the surface of the CDT catalyst reduces its activity. Here, we synthesized a core-shell CDT drug consisting of Fe/Fe₃C core and mesoporous graphite carbon shell with biotin modification (denoted FeCNB). The shell and core form a galvanic cells in the physiological electrolyte solution to achieve high-efficiency CDT under physiological pH conditions. The mesoporous in the shell effectively separates the protein corona from the Fe/Fe₃C, avoiding the influence of the protein corona on the catalyst. However, the mesoporous is permeable for the substrate and product of the catalytic reaction. FeCNB also has T2-magnetic resonance imaging (MRI) function and photothermal conversion ability under 808 nm laser irradiation. The tumor heating further improves the CDT effect to achieve a satisfactory synergistic photothermal therapy (PTT)/CDT outcome. In addition, FeCNB degrades in the microenvironment to ensure its excellent biocompatibility. It is the first study of CDT drug design and fabrication based on the mechanism of the galvanic cells.