Immuno-Nanozymes Mediated Synergistic Chemodynamic/Immuno-Therapy with Potentiated Anti-Tumor Efficacy

Self-assembling gelatin based delivery of multienzyme activity nanozyme and photosensitizer for ROS storm based cancer therapy

Nanozymes with multienzyme activity for reactive oxygen species (ROS) generation and intracellular redox imbalance are attractive strategy for cancer therapy. However, it is severely limited by low biocompatibility and catalytic efficiency, hypoxic and high levels of GSH in the tumor microenvironment. To address these issues, a copper doping carbon nanozyme (CC) with multienzyme activity was designed and integrated with photosensitizer Ce6 and gelatin to fabricate ROS amplifier (CCC). Gelatin endowed CCC with good biocompatibility, low hemolysis, and enzyme responsive degradation. CCC with high CAT-like, POD-like, OXD-like, and GSHox-like activities can induce the intracellular ROS storm formation to eliminate the cancer cells. The OXD-like activity and PDT performance mediated 1O2 generation was markedly potentiated by the CAT-like activity of CCC via catalyzing high expression of H2O2 to generate O2. At the same time, a large amount of ·OH were produced through POD-like activity of CCC and GSH was depleted by the GSHox-like activities of CCC, resulting in a destructive ROS storm formation and cellular redox homeostasis disruption. Both in vivo and in vitro experiments showed that CCC displayed satisfactory anti-tumor activity and biocompatibility. Our work provides a novel strategy for the development of nanozyne enhanced photodynamic therapy of cancer.

Emerging Chemodynamic Nanotherapeutics for Cancer Treatment

Chemodynamic therapy (CDT) has emerged as a transformative paradigm in the realm of reactive oxygen species -mediated cancer therapies, exhibiting its potential as a sophisticated strategy for precise and effective tumor treatment. CDT primarily relies on metal ions and hydrogen peroxide to initiate Fenton or Fenton-like reactions, generating cytotoxic hydroxyl radicals. Its notable advantages in cancer treatment are demonstrated, including tumor specificity, autonomy from external triggers, and a favorable side-effect profile. Recent advancements in nanomedicine are devoted to enhancing CDT, promising a comprehensive optimization of CDT efficacy. This review systematically elucidates cutting-edge achievements in chemodynamic nanotherapeutics, exploring strategies for enhanced Fenton or Fenton-like reactions, improved tumor microenvironment modulation, and precise regulation in energy metabolism. Moreover, a detailed analysis of diverse CDT-mediated combination therapies is provided. Finally, the review concludes with a comprehensive discussion of the prospects and intrinsic challenges to the application of chemodynamic nanotherapeutics in the domain of cancer treatment.

High-Lactate-Metabolizing Photosynthetic Bacteria Reprogram Tumor Immune Microenvironment

The elevated levels of lactate in tumor tissue play a pivotal role in fostering an immunosuppressive microenvironment. Therefore, efficiently reducing lactate levels to reprogram tumor immune microenvironment (TIM) is considered a crucial step for boosted immunotherapy. Here, a high-lactate-metabolizing photosynthetic bacteria (LAB-1) is selectively screened for TIM reprogramming, which then improves the efficacy of tumor immunotherapy. The culture medium for LAB-1 screening is initially developed through an orthogonal experiment, simulating the tumor microenvironment (TME) and utilizing lactate as the sole organic carbon source. As demonstrated in a murine 4T1 model, LAB-1 colonizes the TME selectively, resulting in a significant reduction in lactate levels and a subsequent increase in pH values within the tumor tissue. Furthermore, single-cell RNA sequencing analysis reveals that LAB-1 effectively reprograms the TIM, thereby enhancing the effectiveness of antitumor immune therapy. This approach of utilizing lactate-consuming bacteria represents a potent tool for augmenting tumor immunotherapy efficiency.

Copper Single-Atom-Based Metal-Organic Framework for Ultrasound-Enhanced Nanocatalytic Therapy

Chemodynamic therapy (CDT) is an emerging therapeutic modality triggered by endogenous substances in the tumor microenvironment (TME) to generate reactive oxygen species. However, the mild acid pH, low H2O2 concentration, and overexpressed glutathione can suppress the CDT efficiency. Herein, ultrasound (US)-triggered Cu2+-based single-atom nanoenzymes (FA-NH2-UiO-66-Cu, FNUC) are constructed with the performance of target and glutathione depletion. In the TME, the single-atom Cu sites of FNUC consume glutathione and the FNUC:Cu+ generates •OH via peroxidase-like activity. The US-activated FNUC exhibits a fast •OH generation rate, a low Michaelis constant, and a large •OH concentration, indicating the cavitation effect of US promotes the •OH generation. Meanwhile, the tumor target of FNUC is confirmed by NIR-II fluorescence imaging, in which it is modified with IR-1061. Combined with the antitumor performance of FNUC in vitro and in vivo, the novel Cu-based SAzymes can achieve efficient and precise cancer treatment.

Coordination of iron ions with phycocyanin for an improved Fenton activity at weakly acidic pH

Development of biomolecules coordinated iron ions-based Fenton agents is highly desirable for chemodynamic therapy in term of demanded biocompatibility and enhanced Fenton activity at tumor microenvironmental pH of 6.5. Herein, phycocyanin (PC), the only FDA-approved natural coloring agent, was selected to coordinate with iron ions. The spectroscopic investigations disclosed that PC displayed pH-dependent spectral and conformational responses upon addition of Fe ions. As a result, the effective formation of Fe-PC coordination merely occurred at pH 7 due to a less folded polypeptide matrix of PC. The formed Fe-PC coordination exerted an enhanced Fenton activity at pH 6.5 as attested by 3, 3', 5, 5'-tetramethlbenzidine assay and steady-state kinetic analysis. These findings not only provide fundamental insights of Fe-PC coordination but also highlight the potential biomedical significance of Fe-PC for severing as an effective Fenton agent in chemodynamic therapy.

Tumor-Microenvironment-Responsive Cerium-Enriched Copper Nanozyme with O2 Supply and Oxidative Stress Amplification for In Situ Disulfiram Chemotherapy and Chemodynamic Therapy Intensification

Traditional chemotherapy has faced tough challenges of systemic toxicity, hypoxia resistance, and inadequacy of monotherapy. Developing the tumor-specific O2-supply-enhanced chemotherapy without toxic drugs while combing other precise treatments can substantially improve therapeutic efficacy. Herein, a CeO2-enriched CuO nanozyme with O2 supply and oxidative stress amplification for tumor-specific disulfiram (DSF) chemotherapy and intensified chemodynamic therapy by synergistic in situ "nontoxicity-toxicity" activation is developed. Notably, CeO2 can not only act as a morphological "regulator," but also serve as a cascaded enzyme-mimetic catalyst via tumor-microenvironment-responsive cascaded-logical programmable valence conversion. Once internalized inside tumor cells, the nanozyme can be degraded by lysosomal acidity to release nontoxic DSF and Cu2+, which can trigger in situ "Cu2+-DSF" chelation, generating a highly toxic Cu(DTC)2 for in situ chemotherapy. Moreover, the enriched CeO2 with catalase-mimetic activity can decompose the endogenous H2O2 into O2, which can relieve the hypoxia to enhance the chemotherapeutic efficacy. Furthermore, the simultaneously generated Ce3+ can exert peroxidase-mimetic activity to catalyze H2O2 into hydroxyl radicals (•OH) for chemodynamic therapy. This Fenton-like chemistry is accompanied by the regeneration of Ce4+, which can deplete the intracellular overproduced GSH to amplify the oxidative stress. Therefore, this nanozyme can provide an alternative to precise cancer treatment.

Advances of Layered Double Hydroxide-Based Materials for Tumor Imaging and Therapy

Layered double hydroxides (LDH) are a class of functional anionic clays that typically consist of orthorhombic arrays of metal hydroxides with anions sandwiched between the layers. Due to their unique properties, including high chemical stability, good biocompatibility, controlled drug loading, and enhanced drug bioavailability, LDHs have many potential applications in the medical field. Especially in the fields of bioimaging and tumor therapy. This paper reviews the research progress of LDHs and their nanocomposites in the field of tumor imaging and therapy. First, the structure and advantages of LDH are discussed. Then, several commonly used methods for the preparation of LDH are presented, including co-precipitation, hydrothermal and ion exchange methods. Subsequently, recent advances in layered hydroxides and their nanocomposites for cancer imaging and therapy are highlighted. Finally, based on current research, we summaries the prospects and challenges of layered hydroxides and nanocomposites for cancer diagnosis and therapy.