Triple Tumor Microenvironment-Responsive Ferroptosis Pathways Induced by Manganese-Based Imageable Nanoenzymes for Enhanced Breast Cancer Theranostics

The role of ferroptosis in breast cancer: Tumor progression, immune microenvironment interactions and therapeutic interventions

Ferroptosis represents a distinctive and distinct form of regulated cellular death, which is driven by the accumulation of lipid peroxidation. It is distinguished by altered redox lipid metabolism and is linked to a spectrum of cellular activities, including cancer. In breast cancer (BC), with triple negative breast cancer (TNBC) being an iron-and lipid-rich tumor, inducing ferroptosis was thought to be a novel approach to killing breast tumor cells. However, in the recent past, a novel conceptual framework has emerged which posits that in addition to the promotion of tumor cell death, ferritin deposition has a potent immunosuppressive effect on the tumor immune microenvironment (TIME) via the influence on both innate and adaptive immune responses. TIME of BC includes various cell populations from both the innate and adaptive immune systems. In this review, the internal association between iron homeostasis and the progression of ferroptosis, along with the common inducers and protectors of ferroptosis in BC, are discussed in detail. Furthermore, a comprehensive analysis is conducted on the dual role of ferroptosis in immune cells and proto-oncogenic functions, along with an evaluation of the potential applications of immunogenic cell death-targeted immunotherapy in TIME of BC. It is anticipated that our review will inform future research endeavors that seek to integrate ferroptosis and immunotherapy in the management of BC.

The cGAS-STING-mediated ROS and ferroptosis are involved in manganese neurotoxicity

Manganese (Mn) has been characterized as an environmental pollutant. Excessive releases of Mn due to human activities have increased Mn levels in the environment over the years, posing a threat to human health and the environment. Long-term exposure to high concentrations of Mn can induce neurotoxicity. Therefore, toxicological studies on Mn are of paramount importance. Mn induces oxidative stress through affecting the level of reactive oxygen species (ROS), and the overabundance of ROS further triggers ferroptosis. Additionally, Mn2+ was found to be a novel activator of the cyclic guanosine-adenosine synthase (cGAS)-stimulator of interferon genes (STING) pathway in the innate immune system. Thus, we speculate that Mn exposure may promote ROS production by activating the cGAS-STING pathway, which further induces oxidative stress and ferroptosis, and ultimately triggers Mn neurotoxicity. This review discusses the mechanism between Mn-induced oxidative stress and ferroptosis via activation of the cGAS-STING pathway, which may offer a prospective direction for future in-depth studies on the mechanism of Mn neurotoxicity.

A hypoxia-activated and tumor microenvironment-remodeling nanoplatform for augmenting sonodynamic-chemodynamic-chemotherapy of breast cancer

The tumor microenvironment (TME) offers a promising approach to enhancing cancer therapy by altering the conditions that support tumor growth and immune evasion. However, tumors are highly heterogeneous, and the TME can vary greatly even within different regions of the same tumor. Moreover, tumors can have evolving resistance mechanisms that limit the effectiveness of therapies. In this paper, we have designed a multifunctional nanoparticle named Lip-Ce6-MnO2-TPZ, making sonodynamic therapy (SDT), chemodynamic therapy (CDT), and hypoxia-activated prodrugs work synergistically to maximize cancer treatment efficacy. The innovative Lip-Ce6-MnO2-TPZ nanoparticle was constructed by loading Ce6, MnO2, and hypoxia responsive drug tirapazamine (TPZ) together into a cytotoxic reactive oxygen species (ROS) responsive nanocarrier. Upon ultrasound (US) irradiation, ROS generated by Ce6 could not only induce cell apoptosis but also accelerate the disassembly of the nanoparticle for enhancing the release of TPZ and MnO2. As a result, SDT consumed oxygen leading to the aggravation of the hypoxic condition in the tumor site for TPZ activation and DNA damage in tumor cells. Meanwhile, the MnO2 was reduced to Mn2+ by GSH and caused antioxidant depletion. Mn2+ triggered CDT through a Fenton-like reaction by converting H2O2 to highly toxic •OH. Overall, the Lip-Ce6-MnO2-TPZ platform could induce the generation of excess ROS combined with antioxidant depletion, resulting in oxidative stress and aberrant redox homeostasis of the TME. This strategy has brought forward the idea of inducing cancer cell death by synergistically working SDT, CDT, and hypoxia-activated prodrugs to maximize the therapeutic efficacy in cancer treatment.

Manganese-Based Nanotherapeutics for Targeted Treatment of Breast Cancer

Breast cancer (BC) is one of the most common cancers among women and is associated with high mortality. Traditional modalities, including surgery, radiotherapy, and chemotherapy, have achieved certain advancements but continue to combat challenges including harm to healthy tissues, resistance to treatment, and adverse drug reactions. The rapid advancements in nanotechnology recently facilitated the exploration of innovative strategies for breast cancer therapy. Manganese-based nanotherapeutics have attracted great attention because of their unique characteristics such as tunable structures/morphologies, versatility, magnetic/optical properties, strong catalytic activities, excellent biodegradability, and biocompatibility. In this review, we highlighted different types of Mn-based nanotherapeutics to modulate TME, including metal-immunotherapy, alleviating tumor hypoxia, and increasing reactive oxygen species production, and we emphasized its role in magnetic resonance imaging (MRI)-guided therapy, photoacoustic imaging, and theranostic-based therapy along with a therapeutic carrier, all of which were discussed in the context of breast cancer. Hopefully, the present review will provide insights into the current landscape and future directions of multifunctional applications of Mn-based nanotherapeutics in the field of breast cancer treatment.

Chemical Design of Magnetic Nanomaterials for Imaging and Ferroptosis-Based Cancer Therapy

Ferroptosis, an iron-dependent form of regulatory cell death, has garnered significant interest as a therapeutic target in cancer treatment due to its distinct characteristics, including lipid peroxide generation and redox imbalance. However, its clinical application in oncology is currently limited by issues such as suboptimal efficacy and potential off-target effects. The advent of nanotechnology has provided a new way for overcoming these challenges through the development of activatable magnetic nanoparticles (MNPs). These innovative MNPs are designed to improve the specificity and efficacy of ferroptosis induction. This Review delves into the chemical and biological principles guiding the design of MNPs for ferroptosis-based cancer therapies and imaging-guided therapies. It discusses the regulatory mechanisms and biological attributes of ferroptosis, the chemical composition of MNPs, their mechanism of action as ferroptosis inducers, and their integration with advanced imaging techniques for therapeutic monitoring. Additionally, we examine the convergence of ferroptosis with other therapeutic strategies, including chemodynamic therapy, photothermal therapy, photodynamic therapy, sonodynamic therapy, and immunotherapy, within the context of nanomedicine strategies utilizing MNPs. This Review highlights the potential of these multifunctional MNPs to surpass the limitations of conventional treatments, envisioning a future of drug-resistance-free, precision diagnostics and ferroptosis-based therapies for treating recalcitrant cancers.

Application of nanoparticles with activating STING pathway function in tumor synergistic therapy

Although immunotherapy is currently one of the most promising methods for cancer treatment, its clinical application is limited due to issues such as excessive autoimmune responses and lack of specificity. Therefore, there is a need to improve immunotherapy by integrating emerging medical technologies with traditional treatments. The activation of the cGAS-STING pathway plays a crucial role in innate immunity and antiviral defense, making it highly promising for immunotherapy and attracting significant attention. In recent years, research on nanomaterials and immunotherapy has achieved groundbreaking progress in the medical field. Due to their unique size, shape, stiffness, surface effects, and quantum size effects, nanomaterials can either carry STING activators or directly activate the STING pathway, offering new opportunities for tumor-specific immunotherapy. These unique advantages of nanomaterials have opened up broader prospects for nanoparticle-based therapies targeting the STING pathway. This paper summarizes the current research on utilizing nanomaterials to activate the STING pathway, detailing the characteristics, classifications, and different approaches for targeting tumor cells. Additionally, it focuses on the latest advancements in combined nanotherapies based on cGAS-STING pathway activation, including the integration of nanomaterial-mediated STING pathway activation with immunotherapy, radiotherapy, chemotherapy, targeted therapy, and photodynamic therapy. This provides new ideas for nanoparticle-based combination therapies involving the STING pathway.

A multi-functional integrated nanoplatform based on a tumor microenvironment-responsive PtAu/MnO2 cascade nanoreactor with multi-enzymatic activities for multimodal synergistic tumor therapy

The utilization or improvement of tumor microenvironment (TME) has become a breakthrough in emerging oncology therapies. To address the limited therapeutic efficacy of single modality, a multi-functional integrated nanoplatform based on a TME-responsive PtAu/MnO2 cascade nanoreactor with multi-enzymatic activities was developed for multimodal synergistic tumor therapy. Benefiting from the slightly acidic environment and high-level glutathione (GSH) in TME, PtAu/MnO2 cascade nanoreactor consumed GSH, followed by the reductive generation of manganese ion (Mn2+) and the release of PtAu nanoparticles (NPs). Then, the multimodal synergistic tumor therapy was activated as follows. First, GSH depletion inhibited the activity of glutathione peroxidase 4 and led to the accumulation of lipid peroxidation, thereby inducing tumor cell ferroptosis. Second, PtAu NPs exhibited catalase-like, glucose oxidase-like and nicotinamide adenine dinucleotide (NADH) oxidase-like activities, which generated oxygen for the cascade reaction to alleviate hypoxia and further depleted glucose, NADH and adenosine triphosphate, leading to the inhibition of tumor cell proliferation via starvation therapy. Third, the production of reactive oxygen species by the oxidase- and peroxidase-like activities of PtAu NPs and the Fenton-like reaction of Mn2+ simultaneously induced tumor cell apoptosis via chemodynamic therapy. Briefly, the in vitro and in vivo results confirmed that the multi-functional integrated nanoplatform based on a PtAu/MnO2 cascade nanoreactor with five nanozyme activities demonstrated outstanding biocompatibility and greater inhibition of tumor growth via synergistic ferroptosis/starvation therapy/apoptosis.

Advances in Manganese-based nanomaterials for cancer therapy via regulating Non-Ferrous ferroptosis

Ferroptosis, a regulated form of cell death distinct from apoptosis, was first identified in 2012 and is characterized by iron-dependent lipid peroxidation driven by reactive oxygen species (ROS). Since its discovery, ferroptosis has been linked to various diseases, with recent studies highlighting its potential in cancer therapy, particularly for targeting cancer cells that are resistant to traditional treatments like chemotherapy and radiotherapy. While iron has historically been central to ferroptosis, emerging evidence indicates that non-ferrous ions, especially manganese (Mn), also play a crucial role in modulating this process. Mn-based nanomaterials have shown significant promise in cancer treatment by enhancing ROS production, depleting antioxidant defenses, and inducing ferroptosis. Additionally, these materials offer advantages in tumor imaging, immunotherapy, and catalyzing the Fenton-like reactions essential for ferroptosis. This review delves into the mechanisms of Mn-induced ferroptosis, focusing on recent advancements in Mn-based nanomaterials and their applications in chemodynamic therapy and immunotherapy. By leveraging non-ferrous ion-mediated ferroptosis, these approaches provide a novel avenue for cancer treatment. Furthermore, this review explores the potential role of Mn-based nanomaterials in the lipid metabolism pathways involved in ferroptosis and highlights the advantages of Mn ions over other metals in promoting ferroptosis. These insights offer new perspectives for the development of tumor therapies centered on Mn-based nanomaterials.

Brain-targeting biomimetic disguised manganese dioxide nanoparticles via hybridization of tumor cell membrane and bacteria vesicles for synergistic chemotherapy/chemodynamic therapy of glioma

Glioma is a prevalent brain malignancy associated with poor prognosis. Although chemotherapy serves as the primary treatment for brain tumors, its effectiveness is hindered by the limited ability of drugs to traverse the blood-brain barrier (BBB) and the development of drug resistance linked to tumor hypoxia. Herein, we report the creation of hybrid camouflaged multifunctional nanovesicles comprising membranes of tumor C6 cells (mT) and bacterial outer membrane vesicles (OMVs) and co-loaded with manganese dioxide nanoparticles (MnO2 NPs) and doxorubicin (DOX) to synergistically enhance the chemotherapy/chemodynamic therapy (CDT) of glioma. Owing to OMV-mediated BBB penetration and mT-inherited tumor-homing properties, MnO2-DOX@mT/OMVs can penetrate the BBB and enhance the tumor cell-specific uptake of DOX via "proton sponge effect"-mediated lysosomal escape. This enhances the apoptotic effect induced by DOX and minimizing DOX-associated cardiotoxicity by facilitating the accumulation of DOX at the tumor site. Furthermore, the MnO2 NPs in MnO2-DOX@mT/OMVs can generate potent CDT by accelerating the Fenton-like reaction with DOX-generated H2O2 and achieving glutathione (GSH)-depletion-induced glutathione peroxidase 4 (GPX4) inactivation. These results showed that MnO2-DOX@mT/OMVs, designed for brain tumor targeting, significantly inhibited tumor growth and exhibited favorable biological safety. This innovative approach offers the augmentation of anticancer treatment efficacy via a potential combination of chemotherapy and CDT.

Nuclear-targeted smart nanoplatforms featuring double-shell hollow mesoporous copper sulfide coated with manganese dioxide synergistically potentiate chemotherapy and immunotherapy in hepatocellular carcinoma cells

Smart nanoplatforms designed for nuclear-targeted delivery of chemotherapeutic agents to tumor sites are pivotal in advancing tumor treatment and immunotherapy. Herein, we introduced a novel nuclear-targeting double-shell smart nanoplatform (HMCuS/Pt/ICG@MnO2@9R-P201 (HMCPIM9P)), which synergistically enhances chemotherapy, photodynamic therapy (PDT), photothermal therapy (PTT), immunotherapy and chemodynamic therapy (CDT). The core of this nanoplatform consists of double-shell multifunctional nanoparticles (HMCuS@MnO2) that enable targeted delivery of the photosensitizer Indocyanine Green (ICG) and the chemotherapeutic agent cisplatin (Pt). By effectively consuming glutathione (GSH), these nanoparticles boost the chemotherapeutic efficacy of Pt. Additionally, the manganese ion (Mn2+) present activate the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) (cGAS-STING) pathway, bolstering adaptive immune responses against tumors and elevating the level of tumor-infiltrating CD8+ T cells. The incorporation of the hepatoma-targeting peptide (9R-P201 peptide) allows the system to exhibit FOXM1 receptor-mediated nuclear targeting properties specifically in hepatocellular carcinoma (HCC). Notably, when combined with near-infrared (NIR) light, HMCPIM9P demonstrated a remarkable tumor inhibition rate of 95.6 %, fostered a robust immune response, and significantly inhibited tumor growth and recurrence. Overall, the smart nanoplatform boasts active nuclear targeting capabilities, enabling the enrichment of chemotherapeutic agents at tumor sites, and holds great potential for synergistic applications in enhancing chemotherapy and immunotherapy for HCC.

Albumin-based co-loaded sonosensitizer and STING agonist nanodelivery system for enhanced sonodynamic and immune combination antitumor therapy

STING agonists can activate natural and adaptive immune responses, and are expected to become a new type of immunotherapy drug for tumor therapy. However, how to target deliver STING agonists to tumor tissues is a key factor affecting the efficacy of tumor treatment. Sonodynamic therapy (SDT) has become a research hotspot in the field of cancer treatment due to its non-invasive, spatiotemporally controllable, and high tissue penetration capabilities. Therefore, how to choose the appropriate drug delivery strategy, build a suitable drug delivery system to co-deliver photosensitizers and STING agonists, is a challenge faced in the tumor treatment. In this study, we developed an albumin-based nanodelivery system named FA-ICG&MnOx@HSA that co-loaded the sonosensitizers indocyanine green (ICG) and manganese oxide (MnOx). This approach achieved folate receptor-targeting mediated tumor delivery and tumor microenvironment (TME)-responsive release facilitated by high levels of glutathione (GSH) and hydrogen peroxide (H2O2), which catalyze oxygen generation to potentiate SDT efficacy in killing tumors and inducing immunogenic cell death (ICD). Simultaneously, the released Mn2+ acted as a STING agonist promoting dendritic cell maturation, IFN-β production, and proliferation of T cells. Ultimately, this albumin based co-loaded sonosensitizer and STING agonist demonstrated promising potential for advancing tumor treatment.

Immunomodulatory microneedle patch for enhanced Ferroptosis and immunogenic cell death in postoperative tumor therapy

Microneedle technologies have emerged as a promising transdermal drug delivery platform for postoperative tumor therapy. Despite their potential, enhancing intracellular drug delivery to tumor cells and boosting the therapeutic efficiency of microneedles pose significant challenges. Herein, we develop a nanomedicine-loaded microneedle to enhance the induction of ferroptosis and immunogenic cell death for postoperative tumor therapy. This advancement is achieved by pre-formulating small molecule drugs with transition metal and protein templates into nanomedicine. Upon insertion into the tumors, the microneedle rapidly dissolves, facilitating the release and subsequent cellular uptake of the nanomedicine by tumor cells. Notably, the nanomedicine can release Mn ions and ferroptosis-inducer sulfasalazine (SAS) under acidic conditions. Furthermore, the released Mn ions can produce reactive oxygen species, which decrease the levels of glutathione (GSH) and glutathione peroxidase 4 (GPX4) with increased lipid peroxidation and enhanced induction of ferroptosis. Besides, the treatment stimulates immunogenic cell death through the cell surface exposure of calreticulin (CRT) and release of high-mobility group box 1 (HMGB1), which further stimulates dendric cell maturation, T cell infiltration, and macrophage polarization towards the M1 phenotype. Consequently, this strategy significantly inhibits postoperative tumor regrowth and extends overall survival. Our study indicates the potential of the combination of nanomedicine and microneedle to improve postoperative therapeutic efficiency.

Redox-manipulating nanocarriers for anticancer drug delivery: a systematic review

Spatiotemporally controlled cargo release is a key advantage of nanocarriers in anti-tumor therapy. Various external or internal stimuli-responsive nanomedicines have been reported for their ability to increase drug levels at the diseased site and enhance therapeutic efficacy through a triggered release mechanism. Redox-manipulating nanocarriers, by exploiting the redox imbalances in tumor tissues, can achieve precise drug release, enhancing therapeutic efficacy while minimizing damage to healthy cells. As a typical redox-sensitive bond, the disulfide bond is considered a promising tool for designing tumor-specific, stimulus-responsive drug delivery systems (DDS). The intracellular redox imbalance caused by tumor microenvironment (TME) regulation has emerged as an appealing therapeutic target for cancer treatment. Sustained glutathione (GSH) depletion in the TME by redox-manipulating nanocarriers can exacerbate oxidative stress through the exchange of disulfide-thiol bonds, thereby enhancing the efficacy of ROS-based cancer therapy. Intriguingly, GSH depletion is simultaneously associated with glutathione peroxidase 4 (GPX4) inhibition and dihydrolipoamide S-acetyltransferase (DLAT) oligomerization, triggering mechanisms such as ferroptosis and cuproptosis, which increase the sensitivity of tumor cells. Hence, in this review, we present a comprehensive summary of the advances in disulfide based redox-manipulating nanocarriers for anticancer drug delivery and provide an overview of some representative achievements for combinational therapy and theragnostic. The high concentration of GSH in the TME enables the engineering of redox-responsive nanocarriers for GSH-triggered on-demand drug delivery, which relies on the thiol-disulfide exchange reaction between GSH and disulfide-containing vehicles. Conversely, redox-manipulating nanocarriers can deplete GSH, thereby enhancing the efficacy of ROS-based treatment nanoplatforms. In brief, we summarize the up-to-date developments of the redox-manipulating nanocarriers for cancer therapy based on DDS and provide viewpoints for the establishment of more stringent anti-tumor nanoplatform.

Mapping the evolution and research landscape of ferroptosis-targeted nanomedicine: insights from a scientometric analysis

Objective

Notable progress has been made in "ferroptosis-based nano drug delivery systems (NDDSs)" over the past 11 years. Despite the ongoing absence of a comprehensive scientometric overview and up-to-date scientific mapping research, especially regarding the evolution, critical research pathways, current research landscape, central investigative themes, and future directions.

Methods

Data ranging from 1 January 2012, to 30 November 2023, were obtained from the Web of Science database. A variety of advanced analytical tools were employed for detailed scientometric and visual analyses.

Results

The results show that China significantly led the field, contributing 82.09% of the total publications, thereby largely shaping the research domain. Chen Yu emerged as the most productive author in this field. Notably, the journal ACS Nano had the greatest number of relevant publications. The study identified liver neoplasms, pancreatic neoplasms, gliomas, neoplasm metastases, and melanomas as the top five crucial disorders in this research area.

Conclusion

This research provides a comprehensive scientometric assessment, enhancing our understanding of NDDSs focused on ferroptosis. Consequently, it enables rapid access to essential information and facilitates the extraction of novel ideas in the field of ferroptotic nanomedicine for both experienced and emerging researchers.

Carbon Dot Nanozyme Ameliorating Ischemia-Reperfusion-Induced Muscle Injury by Antioxidation and Downregulating iNOS/COX-2 Pathway

Skeletal muscle ischemia-reperfusion (IR) injury is a prevalent type of muscle injury caused by events, such as trauma, arterial embolism, and primary thrombosis. The development of an IR injury is associated with oxidative stress and an excessive inflammatory response. Nanozymes, which have exceptional free radical scavenging activities, have gained significant attention for treating oxidative stress. This study demonstrates that carbon dot (C-dot) nanozymes possess superoxide dismutase (SOD)-like activity and can act as free radical scavengers. The carbon dot nanozymes are presented to mitigate inflammation by downregulating the iNOS/COX-2 pathway and scavenging reactive oxygen-nitrogen species to reduce oxidative stress, thereby suppressing inflammation. In the IR injury of skeletal muscle mice, we demonstrate that C-dots can effectively reduce inflammatory cytokines and tissue edema in skeletal muscle following IR injury in the limb. These findings suggest that C-dots have potential as a therapeutic approach for IR injury of skeletal muscle with negligible systemic toxicity. This offers a promising strategy for clinical intervention.

Regulation of ferroptosis by nanotechnology for enhanced cancer immunotherapy

INTRODUCTION

This review explores the innovative intersection of ferroptosis, a form of iron-dependent cell death, with cancer immunotherapy. Traditional cancer treatments face limitations in efficacy and specificity. Ferroptosis as a new paradigm in cancer biology, targets metabolic peculiarities of cancer cells and may potentially overcome such limitations, enhancing immunotherapy.

AREA COVERED

This review centers on the regulation of ferroptosis by nanotechnology to augment immunotherapy. It explores how nanoparticle-modulated ferroptotic cancer cells impact the TME and immune responses. The dual role of nanoparticles in modulating immune response through ferroptosis are also discussed. Additionally, it investigates how nanoparticles can be integrated with various immunotherapeutic strategies, to optimize ferroptosis induction and cancer treatment efficacy. The literature search was conducted using PubMed and Google Scholar, covering articles published up to March 2024.

EXPERT OPINION

The manuscript underscores the promising yet intricate landscape of ferroptosis in immunotherapy. It emphasizes the need for a nuanced understanding of ferroptosis' impact on immune cells and the TME to develop more effective cancer treatments, highlighting the potential of nanoparticles in enhancing the efficacy of ferroptosis and immunotherapy. It calls for deeper exploration into the molecular mechanisms and clinical potential of ferroptosis to fully harness its therapeutic benefits in immunotherapy.

The crosstalk between oncogenic signaling and ferroptosis in cancer

Ferroptosis, a novel form of cell death regulation, was identified in 2012. It is characterized by unique features that differentiate it from other types of cell death, including necrosis, apoptosis, autophagy, and pyroptosis. Ferroptosis is defined by an abundance of iron ions and lipid peroxidation, resulting in alterations in subcellular structures, an elevation in reactive oxygen species (ROS), a reduction in glutathione (GSH) levels, and an augmentation in Fe (II) cytokines. Ferroptosis, a regulated process, is controlled by an intricate network of signaling pathways, where multiple stimuli can either enhance or hinder the process. This review primarily examines the defensive mechanisms of ferroptosis and its interaction with the tumor microenvironment. The analysis focuses on the pathways that involve AMPK, p53, NF2, mTOR, System Xc-, Wnt, Hippo, Nrf2, and cGAS-STING. The text discusses the possibilities of employing a combination therapy that targets several pathways for the treatment of cancer. It emphasizes the necessity for additional study in this field.

Ferroptosis and ferroptosis-inducing nanomedicine as a promising weapon in combination therapy of prostate cancer

Incidence and mortality of prostate cancer (PCa) rank in the top five among male tumors. However, single treatment modalities are often restricted due to biochemical recurrence and drug resistance, necessitating the development of new approaches for the combination treatment of castration-resistant and neuroendocrine PCa. Ferroptosis is characterized by the accumulation of iron-overload-mediated lipid peroxidation and has shown promising outcomes in anticancer treatment, prompting us to present a review reporting the application of ferroptosis in the treatment of PCa. First, the process and mechanism of ferroptosis are briefly reviewed. Second, research advances combining ferroptosis-inducing agents and clinical treatment regimens, which exhibit a "two-pronged approach" effect, are further summarized. Finally, the recent progress on ferroptosis-inducing nanomaterials for combination anticancer therapy is presented. This review is expected to provide novel insights into ferroptosis-based combination treatment in drug-resistant PCa.

Targeted Liposomes Sensitize Plastic Melanoma to Ferroptosis via Senescence Induction and Coenzyme Depletion

Ferroptotic cancer therapy has been extensively investigated since the genesis of the ferroptosis concept. However, the therapeutic efficacy of ferroptosis induction in heterogeneous and plastic melanoma has been compromised, because the melanocytic and transitory cell subpopulation is resistant to iron-dependent oxidative stress. Here, we report a phenotype-altering liposomal nanomedicine to enable the ferroptosis-resistant subtypes of melanoma cells vulnerable to lipid peroxidation via senescence induction. The strategy involves the ratiometric coencapsulation of a cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor (palbociclib) and a ferroptosis inducer (auranofin) within cRGD peptide-modified targeted liposomes. The two drugs showed a synergistic anticancer effect in the model B16F10 melanoma cells, as evidenced by the combination index analysis (<1). The liposomes could efficiently deliver both drugs into B16F10 cells in a targeted manner. Afterward, the liposomes potently induced the intracellular redox imbalance and lipid peroxidation. Palbociclib significantly provoked cell cycle arrest at the G0/G1 phase, which sensitized auranofin-caused ferroptosis through senescence induction. Meanwhile, palbociclib depleted intracellular glutathione (GSH) and reduced nicotinamide adenine dinucleotide phosphate (NADPH), further boosting ferroptosis. The proof-of-concept was also demonstrated in the B16F10 tumor-bearing mice model. The current work offers a promising ferroptosis-targeting strategy for effectively treating heterogeneous melanoma by manipulating the cellular plasticity.

Enhancing cell pyroptosis with biomimetic nanoparticles for melanoma chemo-immunotherapy

Despite the fact that immunotherapy has significantly improved the prognosis of melanoma patients, the non-response rate of monoimmunotherapy is considerably high due to insufficient tumor immunogenicity. Therefore, it is necessary to develop alternative methods of combination therapy with enhanced antitumor efficiency and less systemic toxicity. In this study, we reported a cancer cell membrane-coated zeolitic imidazole framework-8 (ZIF-8) encapsulating pyroptosis-inducer oxaliplatin (OXA) and immunomodulator imiquimod (R837) for chemoimmunotherapy. With the assistance of DNA methyltransferase inhibitor decitabine (DCT), upregulated Gasdermin E (GSDME) was cleaved by OXA-activated caspase-3, further inducing tumor cell pyroptosis, then localized antitumor immunity was enhanced by immune adjuvant R837, followed by triggering systemic antitumor immune responses. These results provided a proof-of-concept for the use of cell membrane-coated biomimetic nanoparticles as a promising drug carrier of combination therapy and a potential insight for pyroptosis-based melanoma chemo-immunotherapy.

A pH-Sensitive Nanoparticle as Reactive Oxygen Species Amplifier to Regulate Tumor Microenvironment and Potentiate Tumor Radiotherapy

Background

Radiotherapy is a widely used clinical tool for tumor treatment but can cause systemic toxicity if excessive radiation is administered. Although numerous nanoparticles have been developed as radiosensitizers to reduce the required dose of X-ray irradiation, they often have limitations, such as passive reliance on radiation-induced apoptosis in tumors, and little consider the unique tumor microenvironment that contributes radiotherapy resistance.

Methods

In this study, we developed and characterized a novel self-assembled nanoparticle containing dysprosium ion and manganese ion (Dy/Mn-P). We systematically investigated the potential of Dy/Mn-P nanoparticles (NPs) as a reactive oxygen species (ROS) amplifier and radiosensitizer to enhance radiation therapy and modulate the tumor microenvironment at the cellular level. Additionally, we evaluated the effect of Dy/Mn-P on the stimulator of interferon genes (STING), an innate immune signaling pathway.

Results

Physicochemical analysis demonstrated the prepared Dy/Mn-P NPs exhibited excellent dispersibility and stability, and degraded rapidly at lower pH values. Furthermore, Dy/Mn-P was internalized by cells and exhibited selective toxicity towards tumor cells compared to normal cells. Our findings also revealed that Dy/Mn-P NPs improved the tumor microenvironment and significantly increased ROS generation under ionizing radiation, resulting in a ~70% increase in ROS levels compared to radiation therapy alone. This enhanced ROS generation inhibited ~92% of cell clone formation and greatly contributed to cytoplasmic DNA exposure. Subsequently, the activation of the STING pathway was observed, leading to the secretion of pro-inflammatory immune factors and maturation of dendritic cells (DCs).

Conclusion

Our study demonstrates that Dy/Mn-P NPs can potentiate tumor radiotherapy by improving the tumor microenvironment and increasing endogenous ROS levels within the tumor. Furthermore, Dy/Mn-P can amplify the activation of the STING pathway during radiotherapy, thereby triggering an anti-tumor immune response. This novel approach has the potential to expand the application of radiotherapy in tumor treatment.

The crosstalk of CD8+ T cells and ferroptosis in cancer

Ferroptosis is an iron-dependent, novel form of programmed cell death characterized by lipid peroxidation and glutathione depletion and is widespread in a variety of diseases. CD8+ T cells are the most important effector cells of cytotoxic T cells, capable of specifically recognizing and killing cancer cells. Traditionally, CD8+ T cells are thought to induce cancer cell death mainly through perforin and granzyme, and Fas-L/Fas binding. In recent years, CD8+ T cell-derived IFN-γ was found to promote cancer cell ferroptosis by multiple mechanisms, including upregulation of IRF1 and IRF8, and downregulation of the system XC-, while cancer cells ferroptosis was shown to enhance the anti-tumor effects of CD8+ T cell by heating the tumor immune microenvironment through the exposure and release of tumor-associated specific antigens, which results in a positive feedback pathway. Unfortunately, the intra-tumoral CD8+ T cells are more sensitive to ferroptosis than cancer cells, which limits the application of ferroptosis inducers in cancer. In addition, CD8+ T cells are susceptible to being regulated by other immune cell ferroptosis in the TME, such as tumor-associated macrophages, dendritic cells, Treg, and bone marrow-derived immunosuppressive cells. Together, these factors build a complex network of CD8+ T cells and ferroptosis in cancer. Therefore, we aim to integrate relevant studies to reveal the potential mechanisms of crosstalk between CD8+ T cells and ferroptosis, and to summarize preclinical models in cancer therapy to find new therapeutic strategies in this review.

Exploring the prognostic potential of m6A methylation regulators in low-grade glioma: implications for tumor microenvironment modulation

BACKGROUND

The biological behavior of low-grade glioma (LGG) is significantly affected by N6-methyladenosine (m6A) methylation, an essential epigenetic alteration. Therefore, it is crucial to create a prognostic model for LGG by utilizing genes that regulate m6A methylation.

METHODS

Using TCGA and GTEx databases. We examined m6A modulator levels in LGG and normal tissues, and investigated PD-L1 and PD-1 expression, immune scores, immune cell infiltration, tumor immune microenvironment (TIME) and potential underlying mechanisms in different LGG clusters. We also performed immunohistochemistry and RT-qPCR to identify essential m6A adjustment factor.

RESULTS

The results showed that m6A regulatory element expression was significantly increased in LGG tissues and was significantly associated with TMIE. A substantial increase in PD-L1 and PD-1 levels in LGG tissues and high-risk cohorts was observed. PD-L1 expression was positively correlated with FTO, ZCCHC4, and HNRNPD, whereas PD-1 expression was negatively correlated with FTO, ZC3H7B, and HNRNPD. The prognostic signature created using regulators of m6A RNA methylation was shown to be strongly associated with the overall survival of LGG patients, and FTO and ZCCHC4 were confirmed as independent prognostic markers by clinical samples. Furthermore, the results revealed different TIME characteristics between the two groups of patients, indicating disrupted signaling pathways associated with LGG.

CONCLUSION

Our results present that the m6A regulators play vital role in regulating PD-L1/PD-1 expression and the infiltration of immune cells, thereby exerting a sizable impact on the TIME of LGG. Therefore, m6A regulators have precise predictive value in the prognosis of LGG.

Exploring the role of m6A methylation regulators in glioblastoma multiforme and their impact on the tumor immune microenvironment

Although the role of N6-Methyladenosine (m6A) methylation factors has been established in multiple cancer types, its involvement in glioblastoma multiforme (GBM) remains limited. This study aims to explore the involvement of m6A regulators in GBM and examine their association with the tumor immune microenvironment (TIME). A comprehensive set of 24 candidate m6A RNA regulators was procured. Consensus clustering was performed based on these regulators to identify distinct GBM clusters. PD-L1 and PD-1 levels, immune cell infiltration, and immune scores were evaluated between two clusters. Prognostic signatures and correlation analysis with TIME were analyzed using Lasso and Spearman's analysis. GBM tissue was collected to verify the correlations. Eighteen m6A regulators (WTAP, YTHDF2, HNRNPC, CAPRIN1, YTHDF3, METTL14, GNL3, ZCCHC4, HNRNPD, YTHDF1, RBM15, PCIF1, RBM27, KIAA1429, MSI2, FTO, ALKBH5, and METTL3), PD-L1, and PD-1 were significantly upregulated in GBM tissue. These regulators were divided into two distinct molecular subtypes (clusters 1 and 2). Cluster 2 exhibited a significant increase in immune score, monocytes, M1 macrophages, activated mast cells, and eosinophils. HNRNPC, YWHAG, and ALKBH5 were significantly associated with TIME and positively correlated with PD-L1. Immune cell invasiveness profiles dynamically changed with copy number changes of these three m6A regulators. Finally, YWHAG and ALKBH5 were found to be independent prognostic indicators of GBM through risk analysis and were experimentally verified with clinical samples. YWHAG and ALKBH5 may be used as prognostic markers for patients with GBM. m6A methylation regulators may play an important role in regulating PD-L1/PD-1 expression and immune infiltration, thus having a significant impact on GBM TIME.