Prussian Blue-Derived Nanoplatform for In Situ Amplified Photothermal/Chemodynamic/Starvation Therapy

Prussian blue nanoparticle-based pH-responsive self-assembly for enhanced photothermal and chemotherapy of tumors

In recent years, there has been growing interest in size-transformable nanoplatforms that exhibit active responses to acidic microenvironments, presenting promising prospects in the field of nanomedicine for tumor therapy. However, the design and fabrication of such size-adjustable nanotherapeutics pose significant challenges compared to size-fixed nanocomposites, primarily due to their distinct pH-responsive requirements. In this study, we developed pH-activated-aggregating nanosystems to integrate chemotherapy and photothermal therapy by creating size-transformable nanoparticles based on Prussian blue nanoparticles (PB NPs) anchored with acid-responsive polyoxometalates (POMs) quantum dots via electrostatic interactions (PPP NPs). Subsequently, we utilized doxorubicin (DOX) as a representative drug to formulate PPPD NPs. Notably, PPPD NPs exhibited a significant response to acidic conditions, resulting in changes in surface charge and rapid aggregation of PPP NPs. Furthermore, the aggregated PPP NPs demonstrated excellent photothermal properties under near-infrared laser irradiation. Importantly, PPPD NPs prolonged their retention time in tumor cells via a size-transformation approach. In vitro cellular assays revealed that the anticancer efficacy of PPPD NPs was significantly enhanced. The IC50 values for the PPPD NPs groupand the PPPD NPs + NIR group were 50.11 μg/mL and 30.9 μg/mL. Overall, this study introduces a novel strategy for cancer therapy by developing size-aggregating nano-drugs with stimuli-responsive properties, holding promise for improved therapeutic outcomes in future combination approaches involving photothermal therapy and chemotherapy.

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.

Metallic Copper-Based Dual-Enzyme Biomimetic Nanoplatform for Mild Photothermal Enhancement of Anticancer Catalytic Activity

Background: Chemodynamic therapy (CDT) is recognized as a promising cancer treatment. Recently, copper sulfide nanostructures have been extensively employed as Fenton-like reagents that catalyze the formation of acutely toxic hydroxyl radicals (·OH) from hydrogen peroxide (H2O2). However, CDT therapeutic potency is restricted by the tumor microenvironment (TME), such as insufficient amounts of hydrogen peroxide, excessive glutathione levels, etc. To address these disadvantages, glucose oxidase (GOx) or catalase (CAT) can be utilized to enhance CDT, while low therapeutic efficacy still inhibits their future applications. Our previous study revealed that mild photothermal effect could boost the CDT catalytic effectiveness as well as GOx enzyme activity over a range. Results: We engineered and constructed a hollow CuS nanoplatform loaded with GOx and CAT, coating with macrophage membranes (M@GOx-CAT@CuS NPs). The nanoplatforms allowed enhancement of the reactive oxygen species creation rate and GOx catalytic activeness of CDT through mild phototherapy directed by photoacoustic imaging. After actively targeting vascular cell adhesion molecule-1 (VCAM-1) in cancer cells mediated by macrophage membrane coating, M@GOx-CAT@CuS NPs released GOx and CAT under near-infrared irradiation. GOx catalyzed the formation of H2O2 and gluconic acid with glucose, creating a better catalytic environment for CDT. Meanwhile, CAT-catalyzed H2O2 decomposition to generate sufficient oxygen, appropriately alleviating the oxygen shortage in the TME. In addition, starvation effects decreased adenosine triphosphate levels and further underregulated heat shock protein expression to reduce the heat resistance of tumor cells, resulting in a better mild phototherapy outcome. Both in vitro and in vivo experiments demonstrated that the newly developed M@GOx-CAT@CuS nanoplatform has remarkable synergistic anticancer therapeutic effects. Conclusion: The cascade reaction-enhanced biomimetic nanoplatform opens up a new avenue for precision tumor diagnostic and therapeutic research.

Cascade-Catalyzed Nanogel for Amplifying Starvation Therapy by Nitric Oxide-Mediated Hypoxia Alleviation

Glucose oxidase (Gox)-mediated starvation therapy offers a prospective advantage for malignancy treatment by interrupting the glucose supply to neoplastic cells. However, the negative charge of the Gox surface hinders its enrichment in tumor tissues. Furthermore, Gox-mediated starvation therapy infiltrates large amounts of hydrogen peroxide (H2O2) to surround normal tissues and exacerbate intracellular hypoxia. In this study, a cascade-catalyzed nanogel (A-NE) was developed to boost the antitumor effects of starvation therapy by glucose consumption and cascade reactive release of nitric oxide (NO) to relieve hypoxia. First, the surface cross-linking structure of A-NE can serve as a bioimmobilization for Gox, ensuring Gox stability while improving the encapsulation efficiency. Then, Gox-mediated starvation therapy efficiently inhibited the proliferation of tumor cells while generating large amounts of H2O2. In addition, covalent l-arginine (l-Arg) in A-NE consumed H2O2 derived from glucose decomposition to generate NO, which augmented starvation therapy on metastatic tumors by alleviating tumor hypoxia. Eventually, both in vivo and in vitro studies indicated that nanogels remarkably inhibited in situ tumor growth and hindered metastatic tumor recurrence, offering an alternative possibility for clinical intervention.

Near-infrared laser-assisted Ag@Chi-PB nanocompounds for synergistically eradicating multidrug-resistant bacteria and promoting diabetic abscess healing

Chronic wound infections, particularly multidrug-resistant microbe-caused infections, have imposed severe challenges in clinical administration. The therapeutic effectiveness of the current strategy using conventional antibiotics is extremely unsatisfactory. The development of novel treatment strategies to inhibit the infections caused by multidrug-resistant bacteria is highly desired. In this work, based on the combination of nanocompounds with the assistance of NIR laser, an antibacterial strategy was designed for MRSA-infected abscesses in diabetic mice. The nanocompounds named Ag@Chi-PB were prepared by using chitosan-coated Prussian blue (PB) as a nanocarrier for silver nanoparticles anchoring. Combined with near-infrared (NIR) laser, the nanocompounds were more efficient at killing Escherichia coli (E. coli) and Methicillin-resistant staphyllococcus aureus (MRSA) in vitro. Notably, MRSA was significantly removed in vivo and promoted diabetic abscess healing by the combined therapy of this nanocompound and NIR laser, owing to the synergistic antibacterial effect of photothermal therapy and release of Ag+. Meanwhile, the nanocompound showed satisfactory biocompatibility and superior biosafety. Collectively, the combination therapy of this nanocompound with the assistance of NIR laser may represent a promising strategy for clinical anti-infection.

Tumor acidification and GSH depletion by bimetallic composite nanoparticles for enhanced chemodynamic therapy of TNBC

Chemodynamic therapy (CDT) based on intracellular Fenton reaction to produce highly cytotoxic reactive oxygen species (ROS) has played an essential role in tumor therapy. However, this therapy still needs to be improved by weakly acidic pH and over-expression of glutathione (GSH) in tumor microenvironment (TEM), which hinders its future application. Herein, we reported a multifunctional bimetallic composite nanoparticle MnO2@GA-Fe@CAI based on a metal polyphenol network (MPN) structure, which could reduce intracellular pH and endogenous GSH by remodeling tumor microenvironment to improve Fenton activity. MnO2 nanoparticles were prepared first and MnO2@GA-Fe nanoparticles with Fe3+ as central ion and gallic acid (GA) as surface ligands were prepared by the chelation reaction. Then, carbonic anhydrase inhibitor (CAI) was coupled with GA to form MnO2@GA-Fe@CAI. The properties of the bimetallic composite nanoparticles were studied, and the results showed that CAI could reduce intracellular pH. At the same time, MnO2 could deplete intracellular GSH and produce Mn2+ via redox reactions, which re-established the TME with low pH and GSH. In addition, GA reduced Fe3+ to Fe2+. Mn2+ and Fe2+ catalyzed the endogenous H2O2 to produce high-lever ROS to kill tumor cells. Compared with MnO2, MnO2@GA-Fe@CAI could reduce the tumor weight and volume for the xenograft MDA-MB-231 tumor-bearing mice and the final tumor inhibition rate of 58.09 ± 5.77%, showing the improved therapeutic effect as well as the biological safety. Therefore, this study achieved the high-efficiency CDT effect catalyzed by bimetallic through reshaping the tumor microenvironment.

A TME-activated nano-catalyst for triple synergistic therapy of colorectal cancer

Colorectal cancer cells are highly heterogeneous and exhibit various drug resistances, making personalized treatment necessary. This typically involves a combination of different treatment modalities such as surgery, radiation, and chemotherapy to increase patient survival. Inspired by this, synergistic therapy, which combines multiple modalities into a single nanotherapeutic drug, shows promise in treating cancer. In this study, a nano-catalyst based on calcium peroxide (CaO2) and the chemotherapeutic drug doxorubicin hydrochloride (DOX) co-loaded into HPB nanoparticles (HPB@CaO2/DOX-PAA) was developed to achieve synergistic cancer treatment through chemodynamic/chemo/photothermal (CDT/CT/PTT) mechanisms. After being endocytosed by cancer cells, the nano-catalyst decomposes, releasing cargo. During near-infrared light irradiation, HPB induces a photothermal effect, DOX exhibits significant RNA and DNA destruction capabilities, meanwhile CaO2 produces a large amount of H2O2 in the moderately acidic TME, which combines with Fe2+ ions derived from HPB to form the highly toxic •OH in a Fenton-like reaction, enhancing the chemodynamic treatment. Assays conducted ex vivo and in vivo have exhibited the efficacy of this triple synergistic therapeutic regimen, indicating its potential clinical application.

Synergistic cerium oxide nanozymes: targeting DNA damage and alleviating tumor hypoxia for improved NSCLC radiotherapy efficiency

Radiotherapy (RT) is one of the important treatment modalities for non-small cell lung cancer (NSCLC). However, the maximum radiation dose that NSCLC patient can receive varies little. Therefore, the exploitation of novel RT sensitization approaches is a critical need for the clinical treatment. RT resistance in NSCLC is linked to tumor microenvironment (TME) hypoxia, cell cycle arrest and associated genetic alterations. Here, we designed a novel method for targeted delivery of quercetin (QT) and CeO2 to enhance RT sensitivity. We loaded QT into CeO2@ZIF-8-HA nanoparticles to prevent its degradation in the circulatory system and successfully delivered QT and CeO2 targeted to NSCLC tumors. Under the protection and targeted delivery of Zeolitic Imidazolate Framework-8 (ZIF-8), the nanocomplexes exhibited excellent catalytic mimetic activity in decomposing H2O2 into O2, thus significantly reversing the hypoxia of TME, while the radiosensitizer QT caused DNA damage directly after RT. In a subcutaneous tumor model, CeO2@ZIF-8-HA overcame radiation resistance and enhanced therapeutic efficacy. This multiple sensitization strategy combining delivery of QT and CeO2@ZIF-8-HA nanozymes opens a promising approach for RT of NSCLC.

A Glucose Metabolic Intervention Nanoplatform for Enhanced Chemodynamic Therapy and Sensitized Photothermal Therapy of Hepatocellular Carcinoma

Traditional treatments for hepatocellular carcinoma (HCC) still lack effectiveness. Recently, the combined mode of chemodynamic therapy (CDT) and photothermal therapy (PTT) has shown great potential against HCC. However, insufficient Fenton reaction rates and hyperthermia-induced heat shock responses greatly impair their efficiency, hindering their further clinical application. Here, we constructed a cascade-amplified PTT/CDT nanoplatform by coating an IR780-embedded red blood cell membrane on glucose oxidase (GOx)-loaded Fe₃O₄ nanoparticles for effective HCC treatment. On the one hand, the nanoplatform interfered with glucose metabolism through the action of GOx to reduce the synthesis of ATP, which reduced the expression of heat shock proteins, thereby sensitizing the IR780-mediated PTT. On the other hand, hydrogen peroxide generated during GOx catalysis and the thermal effect of PTT accelerated the Fe₃O₄-mediated Fenton reaction, realizing enhanced CDT. Consequently, the sensitized PTT and enhanced CDT for HCC management could be simultaneously achieved by interfering with glucose metabolism, providing an alternative strategy for the effective treatment of tumors.