Precision therapy through breaking the intracellular redox balance with an MOF-based hydrogel intelligent nanobot for enhancing ferroptosis and activating immunotherapy

Synchronously Delivering Melittin and Evoking Ferroptosis via Tumor Microenvironment-Triggered Self-Destructive Metal-Organic Frameworks to Boost Cancer Immunotherapy

The primary goal of treating malignant tumors is to efficiently eliminate the primary tumor and prevent metastasis and recurrence. Unfortunately, the immunosuppressive tumor microenvironment (TME) is a significant obstacle to effective oncotherapy. Herein, a therapeutic strategy based on melittin (MLT) encapsulated in hyaluronic acid-modified metal-organic frameworks (MOFs) is pioneered, focusing on the safe delivery and TME-responsive release of MLT to reshaping the immunosuppressive TME and simultaneously activating the immune system to eradicate cancerous cells. Iron-based MOFs respond to glutathione and pH, degrade within a moderately acidic TME, and achieve tumor-specific release of MLT. Additionally, the iron-mediated Fenton reaction produces reactive oxygen species that augment oxidative stress, ultimately leading to tumor-specific ferroptosis, whereas MLT-induced membrane disruption promotes immunogenic cell death to activate the immune system. In combination with the immune checkpoint inhibitor anti-PD-L1, this nanodrug elicits potent antitumor immune responses, facilitating the infiltration of effector T cells and enhancing systemic antitumor T cell immunity to suppress both primary and distant tumors. This study demonstrates the tremendous potential of nanoscale self-destructive MOFs for the targeted transport and controlled release of MLT and reveals the promoting effect of combined MLT and ferroptosis delivery on cancer immunotherapy.

Ferroptosis: CD8+T cells' blade to destroy tumor cells or poison for self-destruction

Ferroptosis represents an emerging, iron-dependent form of cell death driven by lipid peroxidation. In recent years, it has garnered significant attention in the realm of cancer immunotherapy, particularly in studies involving immune checkpoint inhibitors. This form of cell death not only enhances our comprehension of the tumor microenvironment but is also considered a promising therapeutic strategy to address tumor resistance, investigate immune activation mechanisms, and facilitate the development of cancer vaccines. The combination of immunotherapy with ferroptosis provides innovative targets and fresh perspectives for advancing cancer treatment. Nevertheless, tumor cells appear to possess a wider array of ferroptosis evasion strategies compared to CD8+T cells, which have been conclusively shown to be more vulnerable to ferroptosis. Furthermore, ferroptosis in the TME can create a favorable environment for tumor survival and invasion. Under this premise, both inducing tumor cell ferroptosis and inhibiting T cell ferroptosis will impact antitumor immunity to some extent, and even make the final result run counter to our therapeutic purpose. This paper systematically elucidates the dual-edged sword role of ferroptosis in the antitumor process of T cells, briefly outlining the complexity of ferroptosis within the TME. It explores potential side effects associated with ferroptosis-inducing therapies and critically considers the combined application of ferroptosis-based therapies with ICIs. Furthermore, it highlights the current challenges faced by this combined therapeutic approach and points out future directions for development.

Dual-functional silver nanoparticle-enhanced ZnO nanorods for improved reactive oxygen species generation and cancer treatment

Recent advancements in sonodynamic therapy (SDT) for cancer treatment have highlighted the potential of enhancing reactive oxygen species (ROS) generation and improving therapeutic outcomes. This study introduces zinc oxide (ZnO) nanorods (NRs) in situ loaded with silver nanoparticles (ZnO@Ag NRs), designed to optimize ROS production under ultrasound irradiation and offer significant advantages in tumor specificity and biosafety. The transmission electron microscopy and elemental mapping confirmed the consistent size and monodispersed Ag nanoparticle for ZnO@Ag NR. Sonodynamic properties showed that ZnO@Ag NRs produce higher singlet oxygen and hydroxyl radicals under ultrasound. In vitro studies demonstrated excellent biocompatibility and enhanced cell-killing effects of ZnO@Ag NRs on CT-26 cells, while in vivo results confirmed its superior anti-tumor efficacy and biosafety. Furthermore, the ZnO@Ag NRs' antibacterial properties were also confirmed, suggesting additional benefits in treating cancers associated with bacterial infections. Collectively, these findings establish ZnO@Ag NRs as a potent and safe agent for ultrasound-driven cancer therapy.

MIL-101 magnetic nanocarrier for solid-phase delivery of doxorubicin to breast and lung cancer cells

An efficient strategy for passive delivery of doxorubicin (DOX) to the breast (MDA-MB-231) and lung (A-549) cancer cells is presented and compared with MCF-10A normal breast cells. Two versions of a peptide structure (linear and cyclic) have been designed and assessed. The molecular dynamic simulations in Material Studio2017 exhibited a higher adsorption capacity for L2 (cyclic version) compared with the adsorption capacity of L1 (linear version) on the PG surface by electrostatic interactions between guanidine of arginine and -OH of PG. The prepared final product based on iron oxide nanoparticles and MIL-101(Fe) (formulated as DOX@Fe3O4/MIL-101-(C,L)C[RW]3) is characterized and the drug content has been estimated. The release profiles revealed an ultra-fast stimulus-sensitive model in acidic media, which corroborates a pH-triggered release. The in vitro assessments disclosed that aggregation of nanocargo around the cancer cells and resulted toxicity are more than the neat DOX in the same dosage as DOX@Fe3O4/MIL-101-CC[RW]3. The obtained distinguished features lie in ability to utilize a biocompatible nanocargo structure to release an appropriate dose of DOX in a controlled manner in the cancer cell environment. Moreover, the functionalization of MIL-101 using cyclic and linear peptides and their comparison is one of the important features of this project.

Metal-organic frameworks: potential synergies with cold atmospheric plasmas for cancer control

Metal-organic frameworks (MOFs) have attracted increasing attention for cancer treatment due to their unique characteristics such as crystallized porous structures, high surface area, and diverse and modifiable chemical properties. Despite the plethora of reports on MOF-based onco-therapeutic designs, these nanocomposites have rarely been launched for clinical use, given, at least, one unavoidable concern, i.e., biosafety. Among the diverse possibilities that MOFs can be engaged for cancer treatment, one unignorable opportunity is how MOFs can be combined with other emerging anti-cancer approaches as one treatment modality to resolve issues of either one for surpassed treatment efficacy. Taking cold atmospheric plasmas (CAPs) as an example, this review delineates the unique features of MOFs and discusses the possible synergies they can create with CAPs for mutual benefits. By providing one example on how MOFs can help overcome the issues of other pre-clinical cancer treatment regimens, this review identifies one research niche that may thrive the field of plasma medicine and revolutionize the schema of MOFs for biological applications.

Disrupting redox homeostasis for tumor therapy based on PDT/chemo/ferroptosis therapeutic hybrid liposomes

Synergistic photodynamic therapy (PDT) with other therapeutic modalities can enhance the therapeutic efficacy of tumor treatment and reduce the adverse effects associated with drug leakage and off-target accumulation. However, shaping combined strategies for synergistic therapy remains challenging. Herein, we developed versatile hybrid liposomes self-assembled from Ce6-lipid conjugates and loaded with the chemo drug doxorubicin (DOX) and ferroptosis inducer Fe3O4 nanoparticles for synergistic PDT/chemo/ferroptosis therapy. Abundant ROS are generated by PDT upon 650 nm light irradiation, Fe3O4-mediated Fenton reaction, and DOX-induced apoptosis. Furthermore, amplifying oxidative stress in cancer cells to disrupt cellular redox homeostasis could accelerate tumor cell death through oxidative damage to lipids, proteins, and DNA. Overall, this work highlights liposome-based therapeutic nanoformulations, thus offering a breakthrough redox homeostasis-based synergistic PDT/chemo/ferroptosis therapy for lung cancer.

Metal-Organic Framework-Based Nanomedicines for Ferroptotic Cancer Therapy

As an iron-dependent, non-apoptosis, regulated cell death (RCD) modality, ferroptosis has gained growing attention for cancer therapy. With the development of nanomaterials in the biomedical field, ferroptotic cancer nanomedicine is extensively investigated. Amongst various nanomaterials, metal-organic frameworks (MOFs) are hybridized porous materials consisting of metal ions or clusters bridged by organic linkers. The superior properties of MOFs, such as high porosity and cargo loading, ease of surface modification, and good biocompatibility, make them appealing in inducing or sensitizing ferroptotic cell death. There are remarkable achievements in the field of MOF-based ferroptosis cancer therapy. However, this topic is not reviewed. This review will introduce the fundamentals of MOF and ferroptosis machinery, summarize the recent progress of MOF-based ferroptotic anticancer drug delivery, discuss the benefits and problems of MOFs as vehicles and sensitizers for cancer ferroptosis, and provide the perspective on future research direction on this promising field.

Ferroptosis-Based Therapeutic Strategies toward Precision Medicine for Cancer

Ferroptosis is a type of iron-dependent programmed cell death characterized by the dysregulation of iron metabolism and the accumulation of lipid peroxides. This nonapoptotic mode of cell death is implicated in various physiological and pathological processes. Recent findings have underscored its potential as an innovative strategy for cancer treatment, particularly against recalcitrant malignancies that are resistant to conventional therapies. This article focuses on ferroptosis-based therapeutic strategies for precision cancer treatment, covering the molecular mechanisms of ferroptosis, four major types of ferroptosis inducers and their inhibitory effects on diverse carcinomas, the detection of ferroptosis by fluorescent probes, and their implementation in image-guided therapy. These state-of-the-art tactics have manifested enhanced selectivity and efficacy against malignant carcinomas. Given that the administration of ferroptosis in cancer therapy is still at a burgeoning stage, some major challenges and future perspectives are discussed for the clinical translation of ferroptosis into precision cancer treatment.

CoFeSe2 @DMSA@FA Nanocatalyst for Amplification of Oxidative Stress to Achieve Multimodal Tumor Therapy

Nanomedicine has significantly advanced precise tumor therapy, providing essential technical blessing for active drug accumulation, targeted consignment, and mitigation of noxious side effects. To enhance anti-tumor efficacy, the integration of multiple therapeutic modalities has garnered significant attention. Here, we designed an innovative CoFeSe2 @DMSA@FA nanocatalyst with Se vacancies (abbreviated as CFSDF), which exhibits synergistic chemodynamic therapy (CDT) and photothermal therapy (PTT), leading to amplified tumor oxidative stress and enhanced photothermal effects. The multifunctional CFSDF nanocatalyst exhibits the remarkable ability to catalyze the Fenton reaction within the acidic tumor microenvironment, efficiently converting hydrogen peroxide (H2 O2 ) into highly harmful hydroxyl radicals (⋅OH). Moreover, the nanocatalyst effectively diminishes GSH levels and ameliorates intracellular oxidative stress. The incorporation of FA modification enables CFSDF to evade immune detection and selectively target tumor tissues. Numerous in vitro and in vivo investigations have consistently demonstrated that CFSDF optimizes its individual advantages and significantly enhances therapeutic efficiency through synergistic effects of multiple therapeutic modalities, offering a valuable and effective approach to cancer treatment.

Multifunctional nano MOF drug delivery platform in combination therapy

Recent preclinical and clinical studies have demonstrated that for cancer treatment, combination therapies are more effective than monotherapies in reducing drug-related toxicity, decreasing drug resistance, and improving therapeutic efficacy. With the rapid development of nanotechnology, the combination of metal-organic frameworks (MOFs) and multi-mode therapy offers a realistic possibility to further improve the shortcomings of cancer treatment. This article focuses on the latest developments, achievements, and treatment strategies of representative multifunctional MOF combination therapies for cancer treatment in recent years, which include not only bimodal combination therapies, but also multi-modal synergistic therapies, further demonstrating the effectiveness and superiority of the MOF drug delivery systems in cancer treatment.

Photodynamic Therapy Combined with Ferroptosis Is a Synergistic Antitumor Therapy Strategy

Ferroptosis is a programmed death mode that regulates redox homeostasis in cells, and recent studies suggest that it is a promising mode of tumor cell death. Ferroptosis is regulated by iron metabolism, lipid metabolism, and intracellular reducing substances, which is the mechanism basis of its combination with photodynamic therapy (PDT). PDT generates reactive oxygen species (ROS) and 1O2 through type I and type II photochemical reactions, and subsequently induces ferroptosis through the Fenton reaction and the peroxidation of cell membrane lipids. PDT kills tumor cells by generating excessive cytotoxic ROS. Due to the limited laser depth and photosensitizer enrichment, the systemic treatment effect of PDT is not good. Combining PDT with ferroptosis can compensate for these shortcomings. Nanoparticles constructed by photosensitizers and ferroptosis agonists are widely used in the field of combination therapy, and their targeting and biological safety can be improved through modification. These nanoparticles not only directly kill tumor cells but also further exert the synergistic effect of PDT and ferroptosis by activating antitumor immunity, improving the hypoxia microenvironment, and inhibiting the tumor angiogenesis. Ferroptosis-agonist-induced chemotherapy and PDT-induced ablation also have good clinical application prospects. In this review, we summarize the current research progress on PDT and ferroptosis and how PDT and ferroptosis promote each other.

The crosstalk between ferroptosis and anti-tumor immunity in the tumor microenvironment: molecular mechanisms and therapeutic controversy

The advent of immunotherapy has significantly reshaped the landscape of cancer treatment, greatly enhancing therapeutic outcomes for multiple types of cancer. However, only a small subset of individuals respond to it, underscoring the urgent need for new methods to improve its response rate. Ferroptosis, a recently discovered form of programmed cell death, has emerged as a promising approach for anti-tumor therapy, with targeting ferroptosis to kill tumors seen as a potentially effective strategy. Numerous studies suggest that inducing ferroptosis can synergistically enhance the effects of immunotherapy, paving the way for a promising combined treatment method in the future. Nevertheless, recent research has raised concerns about the potential negative impacts on anti-tumor immunity as a consequence of inducing ferroptosis, leading to conflicting views within the scientific community about the interplay between ferroptosis and anti-tumor immunity, thereby underscoring the necessity of a comprehensive review of the existing literature on this relationship. Previous reviews on ferroptosis have touched on related content, many focusing primarily on the promoting role of ferroptosis on anti-tumor immunity while overlooking recent evidence on the inhibitory effects of ferroptosis on immunity. Others have concentrated solely on discussing related content either from the perspective of cancer cells and ferroptosis or from immune cells and ferroptosis. Given that both cancer cells and immune cells exist in the tumor microenvironment, a one-sided discussion cannot comprehensively summarize this topic. Therefore, from the perspectives of both tumor cells and tumor-infiltrating immune cells, we systematically summarize the current conflicting views on the interplay between ferroptosis and anti-tumor immunity, intending to provide potential explanations and identify the work needed to establish a translational basis for combined ferroptosis-targeted therapy and immunotherapy in treating tumors.

Recent advances in nanoscale metal-organic frameworks for cancer chemodynamic therapy

Chemodynamic therapy (CDT), a novel therapeutic approach based on Fenton (Fenton-like) reaction, has been widely employed for tumor therapy. This approach utilizes Fe, Cu, or other metal ions (Mn, Zn, Co, or Mo) to react with the excess hydrogen peroxide (H₂O₂) in tumor microenvironments (TME), and form highly cytotoxic hydroxyl radical (˙OH) to kill cancer cells. Recently, nanoscale metal-organic frameworks (nMOFs) have attracted considerable attention as promising CDT agents with the rapid development of cancer CDT. This review focuses on summarizing the latest advances (2020-2022) on the design of nMOFs as nanomedicine for CDT or combination therapy of CDT and other therapies. The future development and challenges of CDT are also proposed based on recent progress. Our group hopes that this review will enlighten the research and development of nMOFs for CDT.

Precisely designed Fex (x = 1-2) cluster nanocatalysts for effective nanocatalytic tumor therapy

Atomically dispersed metal clusters are considered as promising nanocatalysts due to their excellent physicochemical properties. Here, we report a novel strategy for precisely designing Fe_x (x = 1-2) cluster nanocatalysts (Fe₁-N-C and Fe₂-N-C) with dual catalytic activity, which can catalyze H₂O₂ into reactive oxygen species (ROS) and oxidize glutathione (GSH) into glutathione disulfide simultaneously. The adsorption energies of Fe-N sites in Fe₂-N-C for GSH and H₂O₂ intermediates were well controlled due to the orbital modulation of adjacent Fe sites, contributing to the higher dual catalytic activity compared to Fe₁-N-C. Additionally, tamoxifen (TAM) was loaded into Fe₂-N-C (Fe₂@TDF NEs) to down-regulate the intracellular pH for higher Fenton-like catalytic efficiency and ROS production. The generated ROS could induce apoptosis and lipid peroxidation, triggering ferroptosis. Meanwhile, upregulation of ROS and lipid peroxidation, along with GSH depletion and GPX4 downregulation could promote the apoptosis and ferroptosis of tumor cells. In addition, the lactic acid accumulation effect of TAM and the high photothermal conversion ability of Fe₂@TDF NEs could further enhance the catalytic activity to achieve synergistic antitumor effects. As a result, this work highlights the critical role of adjacent metal sites at the atomic-level and provides a rational guidance for the design and application of nanocatalytic antitumor systems.

Carrier-Free H2 O2 Self-Supplier for Amplified Synergistic Tumor Therapy

Chemodynamic therapy (CDT) utilizes Fenton or Fenton-like reactions to convert hydrogen peroxide (H₂ O₂ ) into cytotoxic hydroxyl radicals (•OH) and draws extensive interest in tumor therapy. Nevertheless, high concentrations of glutathione (GSH) and insufficient endogenous H₂ O₂ often cause unsatisfactory therapeutic efficacy. Herein, a GSH-depleting and H₂ O₂ self-providing carrier-free nanomedicine that can efficiently load indocyanine green (ICG), β-lapachone (LAP), and copper ion (Cu²⁺ ) (ICG-Cu²⁺ -LAP, LICN) to mediate synergetic photothermal and chemotherapy in enhanced chemodynamic therapy is designed. The results show that  LICNs successfully enter tumors owing to the enhanced permeability and retention effect. Through the reductive intracellular environment, Cu²⁺ in LICN can react with intracellular GSH, alleviate the antioxidant capacity of tumor tissues, and trigger the release of drugs. When LICN is subjected to near-infrared (NIR) irradiation, enhanced photothermal effect and upregulated expression of NAD(P)H quinone oxidoreductase-1 (NQO1) are observed. Meanwhile, the released LAP not only supports chemotherapy but also catalyzes NQO1 and produces sufficient endogenous H₂ O₂ , thereby increasing the efficiency of Cu⁺ -based Fenton-like reaction. Notably, GSH depletion and H₂ O₂ self-sufficiency generate sufficient •OH and kill tumor cells with high specificity. Overall, the study provides an innovative strategy to self-regulate GSH and H₂ O₂ levels for effective anticancer therapy.