Ferrocene-liposome-PEG: a robust ˙OH/lipid peroxide nano-converter for inducing tumor ferroptosis

Cascade Hydroxyl Radical-Generating and Ferroptosis-Inducing Nanofiber System for the Therapy of Oral Squamous Cell Carcinoma

Nanofiber (NF) membrane systems that can provide cascade catalytic reaction and ferroptosis induction were developed for oral cancer therapy. Glucose oxidase (GOx) and aminoferrocene (AF) were introduced into the NF system for glucose deprivation/H2O2 generation and OH radical generation, respectively. GOx offers starvation therapy and AF (including iron) provides chemodynamic therapy/ferroptosis for combating oral cancer. GOx (water-soluble) and AF (poorly water-soluble) molecules were successfully entrapped in the NF membrane via an electrospinning process. GOx and AF were incorporated into the polyvinyl alcohol (PVA)-based NF, resulting in PVA/GOx/AF NF with fast disintegration and immediate drug-release properties. In oral squamous cell carcinoma (YD-9 cells), the PVA/GOx/AF NF group exhibited higher cytotoxicity, antiproliferation potential, cellular ROS level, apoptosis induction, lipid ROS level, and malondialdehyde level compared to the other NF groups. The electrospun PVA/GOx/AF NF can be directly applied to oral cancer without causing pain, offering starvation/chemodynamic therapy and ferroptosis induction.

Cu(II) complex that synergistically potentiates cytotoxicity and an antitumor immune response by targeting cellular redox homeostasis

Developing anticancer drugs with low side effects is an ongoing challenge. Immunogenic cell death (ICD) has received extensive attention as a potential synergistic modality for cancer immunotherapy. However, only a limited set of drugs or treatment modalities can trigger an ICD response and none of them have cytotoxic selectivity. This provides an incentive to explore strategies that might provide more effective ICD inducers free of adverse side effects. Here, we report a metal-based complex (Cu-1) that disrupts cellular redox homeostasis and effectively stimulates an antitumor immune response with high cytotoxic specificity. Upon entering tumor cells, this Cu(II) complex enhances the production of intracellular radical oxidative species while concurrently depleting glutathione (GSH). As the result of heightening cellular oxidative stress, Cu-1 gives rise to a relatively high cytotoxicity to cancer cells, whereas normal cells with low levels of GSH are relatively unaffected. The present Cu(II) complex initiates a potent ferroptosis-dependent ICD response and effectively inhibits in vivo tumor growth in an animal model (c57BL/6 mice challenged with colorectal cancer). This study presents a strategy to develop metal-based drugs that could synergistically potentiate cytotoxic selectivity and promote apoptosis-independent ICD responses through perturbations in redox homeostasis.

Liposome encapsulated polydopamine nanoparticles: Enhancing ferroptosis and activating hypoxia prodrug activity

The short lifespan of active oxygen species and depressed O2 level during ferroptosis treatment in tumor cells weaken ferroptosis therapy. How to improve the utilization efficiency of active oxygen species generated in real time is pivotal for anticancer treatment. Herein, the tirapazamine (TPZ) loaded polydopamine-Fe nanoparticles (PDA-Fe-TPZ) was modified with unsaturated liposome (Lip), which was constructed to overcome the drawbacks of traditional ferroptosis therapy. The Lip@PDA-Fe-TPZ nanoliposomes can react with H2O2 to produce •OH by Fenton reaction, which then attacks Lip and transforms into radical intermediate (L•) and phospholipid peroxide radical (LOO•) to avoid the annihilation of •OH. The introduced Lip enhances lipid peroxidation and promotes oxygen consumption, resulting in increased hypoxia at tumor site. The introduced TPZ can be triggered by reductase in tumor cells under hypoxia, which can reduce to transient oxidative free radicals by reductase enzymes and destroy the structure of the surrounding biomacromolecules, thus achieving the synergistic treatment of ferroptosis and chemotherapy. In this work, we organically combined enhanced ferrroptosis with hypoxic activated chemotherapy to achieve efficient and specific tumor killing effect, which can sever as a promising treatment of cancer in the future.

Biomimetic Nanoarchitectonics with Chitosan Nanogels for Collaborative Induction of Ferroptosis and Anticancer Immunity for Cancer Therapy

Immunogenic cell death (ICD) shows promising therapeutic potential for tumor regression. However, the low sensitivity and immunosuppressive state of current cell death manners seriously impede tumor immunogenicity. Ferroptosis characterized by excessive lipid peroxidation, has emerged as a potential strategy to induce ICD and activate antitumor immune responses. However, the effectiveness of ferroptosis is limited by antioxidant regulatory networks, including the glutathione peroxidase 4 (GPX4) and ferroptosis suppressor protein 1 (FSP1) pathways, presenting challenges for its induction. Herein, they propose a novel approach that involves utilizing functionalized chitosan-ferrocene-sodium alginate (CFA) crosslinked nanogels, which are modified to pravastatin (PRV) and M1 macrophage membrane (MM) (designing as CFA/PRV@MM). Specifically, ferrocene boots intracellular reactive oxygen species levels for efficient glutathione (GSH) depletion through Fenton reaction, thus disrupting the GPX4/GSH axis, while PRV intervenes in the mevalonate pathway to inhibit the FSP1/CoQ10 antioxidant axis, thereby synergistically causing pronounced ferroptotic damage and promoting ICD. The CFA/PRV@MM nanogels demonstrate superior therapeutic efficacy in a mouse breast model, resulting in effective tumor ablation and immune response with minimal side effects. RNA transcription analysis reveals that nanogels can significantly affect metabolic progress, as well as immune activation. This research provides valuable insights into the design of ferroptosis induction for cancer immunotherapy.

Recent progress in biomaterials-driven ferroptosis for cancer therapy

Ferroptosis, first suggested in 2012, is a type of non-apoptotic programmed cell death caused by the buildup of lipid peroxidation and marked by an overabundance of oxidized poly unsaturated fatty acids. During the last decade, researchers have uncovered the formation of ferroptosis and created multiple drugs aimed at it, but due to poor selectivity and pharmacokinetics, clinical application has been hindered. In recent years, biomedical discoveries and developments in nanotechnology have spurred the investigation of ferroptosis nanomaterials, providing new opportunities for the ferroptosis driven tumours treatment. Additionally, hydrogels have been widely studied in ferroptosis because of their unique 3D structure and excellent controllability. By using these biomaterials, it is possible to achieve controlled release and targeted delivery of drugs, thus increasing the potency of the drugs and minimizing adverse effects. Therefore, summarizing the biomedical nanomaterials, including hydrogels, used in ferroptosis for cancer therapy is a must. This article provides an overview of ferroptosis, detailing its properties and underlying mechanisms. It also categorizes and reviews the use of various nanomaterials in ferroptosis, along with relevant explanations and illustrations. In addition, we discuss the opportunities and challenges facing the application of nanomaterials in ferroptosis. Finally, the development prospects of this field are prospected. This review is intended to provide a foundation for the development and application of biomedical nanomaterials in ferroptosis.

A Dual Heat Shock Protein Down-Regulation Strategy Using PDA/Cu/ICG/R Controlled by NIR "Switch" Enhances Mild-Photothermal Therapy Effect

The purpose of this study is to down-regulate heat shock proteins and improve the mild photothermal therapy (mild-PTT) effect of polydopamine (PDA) by preparing the nanosystem of Cu2+ and indocyanine green (ICG)-loaded PDA nanospheres with surface modification of integrin-targeted cyclic peptide (cRGD) (PDA/Cu/ICG/R), which can limit ATP synthesis through the double mitochondrial destruction pathway. In vitro and in vivo experiments using PDA/Cu/ICG/R irradiated with an NIR laser demonstrate that when NIR is "OFF," Cu2+ can undergo Fenton-like reaction in tumor cells, producing a large amount of hydroxyl radicals (·OH), which leads to oxidative stress in cells. This oxidative stress can cause mitochondrial oxidative phosphorylation dysfunction, resulting in limited ATP synthesis. When NIR is "ON," mild-PTT can accelerate Cu2+ to produce ·OH. Simultaneously, NIR can activate ICG to produce reactive oxygen species (ROS) storm, amplify intracellular oxidative stress, and continuously damage mitochondria. The biodegradability of PDA greatly reduces the risk of toxicity caused by long-term retention of PDA/Cu/ICG/R in organisms. Finally, the improvement of the mild-PTT effect of PDA is successfully achieved through the double mitochondrial destruction pathway of Cu2+ and ICG controlled by NIR "switch."

Effects of Ferrocene and Ferrocenium on MCF-7 Breast Cancer Cells and Interconnection with Regulated Cell Death Pathways

The effects of ferrocene (Fc) and ferrocenium (Fc+) induced in triple negative human breast cancer MCF-7 cells were explored by immunofluorescence, flow cytometry, and transmission electron microscopy analysis. The different abilities of Fc and Fc+ to produce reactive oxygen species and induce oxidative stress were clearly observed by activating apoptosis and morphological changes after treatment, but also after tests performed on the model organism D. discoideum, particularly in the case of Fc+. The induction of ferroptosis, an iron-dependent form of regulated cell death driven by an overload of lipid peroxides in cellular membranes, occurred after 2 h of treatment with Fc+ but not Fc. However, the more stable Fc showed its effects by activating necroptosis after a longer-lasting treatment. The differences observed in terms of cell death mechanisms and timing may be due to rapid interconversion between the two oxidative forms of internalized iron species (from Fe2+ to Fe3+ and vice versa). Potential limitations include the fact that iron metabolism and mitophagy have not been investigated. However, the ability of both Fc and Fc+ to trigger different and interregulated types of cell death makes them suitable to potentially overcome the shortcomings of traditional apoptosis-mediated anticancer therapies.

In Situ Construction of Ferrocene-Containing Membrane-Bound Nanofibers for the Redox Control of Cancer Cell Death and Cancer Therapy

Precise manipulation of cancer cell death by harnessing reactive oxygen species (ROS) is a promising strategy to defeat malignant tumors. However, it is quite difficult to produce active ROS with spatial precision and regulate their biological outcomes. We succeed here in selectively generating short-lived and lipid-reactive hydroxyl radicals (•OH) adjacent to cancer cell membranes, successively eliciting lipid peroxidation and ferroptosis. DiFc-K-pY, a phosphorylated self-assembling precursor that consists of two branched Fc moieties and interacts specifically with epidermal growth factor receptor, can in situ produce membrane-bound nanofibers and enrich ferrocene moieties on cancer cell membranes in response to alkaline phosphatase. Within the acidic tumor microenvironment, DiFc-K-pY nanofibers efficiently convert tumoral H2O2 to active •OH around the target cell membranes via Fenton-like reactions, leading to lipid peroxidation and ferroptosis with good cellular selectivity. Our strategy successfully prevents tumor progression with acceptable biocompatibility through intratumoral administration.

Ferroptosis in Haematological Malignancies and Associated Therapeutic Nanotechnologies

Haematological malignancies are heterogeneous groups of cancers of the bone marrow, blood or lymph nodes, and while therapeutic advances have greatly improved the lifespan and quality of life of those afflicted, many of these cancers remain incurable. The iron-dependent, lipid oxidation-mediated form of cell death, ferroptosis, has emerged as a promising pathway to induce cancer cell death, particularly in those malignancies that are resistant to traditional apoptosis-inducing therapies. Although promising findings have been published in several solid and haematological malignancies, the major drawbacks of ferroptosis-inducing therapies are efficient drug delivery and toxicities to healthy tissue. The development of tumour-targeting and precision medicines, particularly when combined with nanotechnologies, holds potential as a way in which to overcome these obstacles and progress ferroptosis-inducing therapies into the clinic. Here, we review the current state-of-play of ferroptosis in haematological malignancies as well as encouraging discoveries in the field of ferroptosis nanotechnologies. While the research into ferroptosis nanotechnologies in haematological malignancies is limited, its pre-clinical success in solid tumours suggests this is a very feasible therapeutic approach to treat blood cancers such as multiple myeloma, lymphoma and leukaemia.