Injectable microenvironment-responsive hydrogels with redox-activatable supramolecular prodrugs mediate ferroptosis-immunotherapy for postoperative tumor treatment

Electron Pump and Photon Trap Effect-Derived Selective Antitumor of Fe-Ppy@CaO2-Modified Polyetheretherketone for Bone Tumor Therapy

Bone tumors with high mortality and disability have become a major clinical challenge. Herewith, it is necessary to design materials for bone tumor therapy and bone repair. In this work, Fe-doped polypyrrole (Fe-Ppy) and CaO2 are constructed on sulfonated polyetheretherketone (SP) to form a multistage-responsive coating. The coating achieves long-lasting antitumor through chemodynamic therapy (CDT), photothermal therapy (PTT), and combined immunotherapy. Fe-Ppy acts as an electron pump to replenish Fe2+ through oxidizing -NH- to -N+-, which lasts the Fenton reaction and persistently produces reactive oxygen species (ROS) in the tumor microenvironment (TME). CaO2 selectively provides exogenous H2O2 in response to TME to boost the electron cycle. Stronger near-infrared light absorption due to Fe doping and more photon traps caused by porous structure-induced scattering and refraction diminishment improve the photothermal conversion of modified SP. Furthermore, long-lasting ROS and effective photothermal conversion enhance M1 activation to secrete TNF-α and IFN to kill tumor cells. After tumor therapy, Fe-Ppy@CaO2-modified SP could adaptively switch the macrophage to M2 and promote osteogenesis with the abolishment of TME and NIR stimulation. In summary, Fe-Ppy@CaO2-modified SP with long-lasting ROS, enhanced photothermal conversion, and immunomodulation is a potential candidate for bone tumor therapy and tissue repair.

Iron-Dependent Cell Death: Exploring Ferroptosis as a Unique Target in Triple-Negative Breast Cancer Management

Triple-negative breast cancer (TNBC) is characterized by aggressive behavior, high metastatic potential, and frequent relapses, presenting significant treatment challenges. Ferroptosis, a unique form of programmed cell death marked by iron-dependent lipid peroxidation, has emerged as a crucial factor in cancer biology. Recent studies indicate that TNBC cells possess a distinct metabolic profile linked to iron and glutathione, which may render them more susceptible to ferroptosis than other breast cancer subtypes. Moreover, ferroptosis plays a role in the interactions between immune cells and tumor cells, suggesting its potential to modulate the tumor microenvironment and influence the immune response against TNBC.Evidence reveals that ferroptosis not only affects TNBC cell viability but also alters the tumor microenvironment by promoting the release of damage-associated molecular patterns (DAMPs), which can recruit immune cells to the tumor site. Specific ferroptosis-related genes and biomarkers, such as ACSL4 and GPX4, demonstrate altered expression patterns in TNBC tissues, offering promising avenues for diagnostic and prognostic applications. Furthermore, in preclinical models, the induction of ferroptosis has been shown to enhance the efficacy of existing therapies, indicating a synergistic effect that could be harnessed for therapeutic benefit. The compelling link between ferroptosis and TNBC underscores its potential as a novel therapeutic target. Future research should focus on developing strategies that exploit ferroptosis in conjunction with traditional therapies, including the identification of natural compounds and efficacious ferroptosis inducers for personalized treatment regimens. This review elucidates the multifaceted implications of ferroptosis in TNBC, providing valuable insights for improving both diagnosis and treatment of this formidable breast cancer subtype.

Biomaterial-Mediated Metabolic Regulation of Ferroptosis for Cancer Immunotherapy

Ferroptosis is a lipid peroxidation-driven cell death route and has attracted enormous interest for cancer therapy. Distinct from other forms of regulated cell death, its process is involved with multiple metabolic pathways including lipids, bioenergetics, iron, and so on, which influence cancer cell ferroptosis sensitivity and communication with the immune cells in the tumor microenvironment. Development of novel technologies for harnessing the ferroptosis-associated metabolic regulatory network would profoundly improve our understanding of the immune responses and enhance the efficacy of ferroptosis-dependent immunotherapy. Interestingly, the recent advances in bio-derived material-based therapeutic platforms offer novel opportunities to therapeutically modulate tumor metabolism through the in situ delivery of molecular or material cues, which not only allows the tumor-specific elicitation of ferroptosis but also holds promise to maximize their immunostimulatory impact. In this review, we will first dissect the crosstalk between tumor metabolism and ferroptosis and its impact on the immune regulation in the tumor microenvironment, followed by the comprehensive analysis on the recent progress in biomaterial-based metabolic regulatory strategies for evoking ferroptosis-mediated antitumor immunity. A perspective section is also provided to discuss the challenges in metabolism-regulating biomaterials for ferroptosis-immunotherapy. We envision that this review may provide new insights for improving tumor immunotherapeutic efficacy in the clinic.

The Mutual Regulatory Role of Ferroptosis and Immunotherapy in Anti-tumor Therapy

Ferroptosis is a form of cell death that is triggered by the presence of ferrous ions and is characterized by lipid peroxidation induced by these ions. The mechanism exhibits distinct morphological characteristics compared to apoptosis, autophagy, and necrosis. A notable aspect of ferroptosis is its ability to inhibit uncontrolled tumor replication and immortalization, especially in malignant, drug-resistant, and metastatic tumors. Additionally, immunotherapy, a novel therapeutic approach for tumors, has been found to have a reciprocal regulatory relationship with ferroptosis in the context of anti-tumor therapy. A comprehensive analysis of ferroptosis and immunotherapy in tumor therapy is presented in this paper, highlighting the potential for mutual adjuvant effects. Specifically, we discuss the mechanisms underlying ferroptosis and immunotherapy, emphasizing their ability to improve the tumor immune microenvironment and enhance immunotherapeutic effects. Furthermore, we investigate how immunotherapeutic factors may increase the sensitivity of tumor cells to ferroptosis. We aim to provide a prospective view of the promising value of combined ferroptosis and immunotherapy in anticancer therapy by elucidating the mutual regulatory network between each.

Ferroptosis in Cancer Therapy: Mechanisms, Small Molecule Inducers, and Novel Approaches

Ferroptosis, a unique form of programmed cell death, is initiated by an excess of iron accumulation and lipid peroxidation-induced damage. There is a growing body of evidence indicating that ferroptosis plays a critical role in the advancement of tumors. The increased metabolic activity and higher iron levels in tumor cells make them particularly vulnerable to ferroptosis. As a result, the targeted induction of ferroptosis is becoming an increasingly promising approach for cancer treatment. This review offers an overview of the regulatory mechanisms of ferroptosis, delves into the mechanism of action of traditional small molecule ferroptosis inducers and their effects on various tumors. In addition, the latest progress in inducing ferroptosis using new means such as proteolysis-targeting chimeras (PROTACs), photodynamic therapy (PDT), sonodynamic therapy (SDT) and nanomaterials is summarized. Finally, this review discusses the challenges and opportunities in the development of ferroptosis-inducing agents, focusing on discovering new targets, improving selectivity, and reducing toxic and side effects.

Advances in Hydrogels of Drug Delivery Systems for the Local Treatment of Brain Tumors

The management of brain tumors presents numerous challenges, despite the employment of multimodal therapies including surgical intervention, radiotherapy, chemotherapy, and immunotherapy. Owing to the distinct location of brain tumors and the presence of the blood-brain barrier (BBB), these tumors exhibit considerable heterogeneity and invasiveness at the histological level. Recent advancements in hydrogel research for the local treatment of brain tumors have sought to overcome the primary challenge of delivering therapeutics past the BBB, thereby ensuring efficient accumulation within brain tumor tissues. This article elaborates on various hydrogel-based delivery vectors, examining their efficacy in the local treatment of brain tumors. Additionally, it reviews the fundamental principles involved in designing intelligent hydrogels that can circumvent the BBB and penetrate larger tumor areas, thereby facilitating precise, controlled drug release. Hydrogel-based drug delivery systems (DDSs) are posited to offer a groundbreaking approach to addressing the challenges and limitations inherent in traditional oncological therapies, which are significantly impeded by the unique structural and pathological characteristics of brain tumors.

Alginate-Chitosan Biodegradable and Biocompatible Based Hydrogel for Breast Cancer Immunotherapy and Diagnosis: A Comprehensive Review

Breast cancer is the most common type of cancer and the second leading cause of cancer-related mortality in females. There are many side effects due to chemotherapy and traditional surgery, like fatigue, loss of appetite, skin irritation, and drug resistance to cancer cells. Immunotherapy has become a hopeful approach toward cancer treatment, generating long-lasting immune responses in malignant tumor patients. Recently, hydrogel has received more attention toward cancer therapy due to its specific characteristics, such as decreased toxicity, fewer side effects, and better biocompatibility drug delivery to the particular tumor location. Researchers globally reported various investigations on hydrogel research for tumor diagnosis. The hydrogel-based multilayer platform with controlled nanostructure has received more attention for its antitumor effect. Chitosan and alginate play a leading role in the formation of the cross-link in a hydrogel. Also, they help in the stability of the hydrogel. This review discusses the properties, preparation, biocompatibility, and bioavailability of various research and clinical approaches of the multipolymer hydrogel made of alginate and chitosan for breast cancer treatment. With a focus on cases of breast cancer and the recovery rate, there is a need to find out the role of hydrogel in drug delivery for breast cancer treatment.

Engineered cyclodextrin-based supramolecular hydrogels for biomedical applications

Cyclodextrin (CD)-based supramolecular hydrogels are polymer network systems with the ability to rapidly form reversible three-dimensional porous structures through multiple cross-linking methods, offering potential applications in drug delivery. Although CD-based supramolecular hydrogels have been increasingly used in a wide range of applications in recent years, a comprehensive description of their structure, mechanical property modulation, drug loading, delivery, and applications in biomedical fields from a cross-linking perspective is lacking. To provide a comprehensive overview of CD-based supramolecular hydrogels, this review systematically describes their design, regulation of mechanical properties, modes of drug loading and release, and their roles in various biomedical fields, particularly oncology, wound dressing, bone repair, and myocardial tissue engineering. Additionally, this review provides a rational discussion on the current challenges and prospects of CD-based supramolecular hydrogels, which can provide ideas for the rapid development of CD-based hydrogels and foster their translation from the laboratory to clinical medicine.