A GPX4-targeted photosensitizer to reverse hypoxia-induced inhibition of ferroptosis for non-small cell lung cancer therapy

Molecular engineering strategies for fabricating type-I mitochondria-targeted aggregation-induced emission photosensitizers for apoptosis-ferroptosis synergistically boosting photodynamic therapy

The precise distribution and subcellular localization of photosensitizers (PSs) play a crucial role in maximizing the utilization of reactive oxygen species (ROS) and enhancing photodynamic therapy (PDT). However, the therapeutic efficacy of PDT is significantly compromised by the hypoxic microenvironment, particularly in malignant tumors. To address these challenges, we designed and synthesized three donor-donor-π-bridge-acceptor (D-D-π-A) type aggregation-induced emission (AIE) PSs: TCM-OTs, TCM-OH, and TCPy-OH. By fine-tuning the acceptor and donor substituents, we successfully modulated organelle-targeting specificity and ROS generation to mitigate hypoxia-related limitations. Among these compounds, TCM-OH emerged as a highly promising PS, exhibiting selective mitochondrial targeting and efficient type-I ROS generation. To further enhance its pharmacological properties, we encapsulated each PS into DSPE-PEG2k to form nanoparticles (NPs). Notably, TCM-OH NPs facilitated the production of superoxide (•O2-) and hydroxyl radicals (•OH) within mitochondria, leading to mitochondrial dysfunction and subsequent cell death via a synergistic ferroptosis-apoptosis pathway under light irradiation. Both in vitro and in vivo experiments demonstrated the potent therapeutic efficacy of this strategy, with minimal toxicity, underscoring its potential for hypoxic cancer treatment. Overall, this study provides a rational design framework for developing potent type-I PSs with multimodal capabilities for biomedical applications.

ML210 Antagonizes ABCB1- Not ABCG2-Mediated Multidrug Resistance in Colorectal Cancer

Objectives: ABCB1-mediated multidrug resistance (MDR) compromises chemotherapy efficacy in colorectal cancer (CRC). Despite decades of research, no selective ABCB1 inhibitor has achieved clinical success. This study investigates ML210 as a novel ABCB1-specific inhibitor to reverse ABCB1-driven MDR. Methods: Cytotoxicity assays (MTT) were performed on ABCB1-overexpressing HCT-8/V and ABCG2-overexpressing S1-M1-80 CRC cells. Drug accumulation (doxorubicin/mitoxantrone) was quantified via flow cytometry, and cell cycle effects were analyzed using propidium iodide staining. Molecular docking utilized the ABCB1 crystal structure. Results: ML210 selectively reversed ABCB1-mediated resistance to doxorubicin and vincristine in HCT-8/V cells, enhancing intracellular drug accumulation without affecting ABCG2 activity. It induced cell cycle arrest in ABCB1-overexpressing cells and did not alter ABCB1 protein expression. Molecular docking revealed stable binding of ML210 within the ABCB1 substrate pocket through hydrophobic interactions and hydrogen bonding. Conclusions: ML210 is a selective ABCB1 inhibitor that circumvents MDR via direct transport blockade, offering a targeted strategy against ABCB1-mediated chemoresistance in CRC. Its specificity for ABCB1 over ABCG2 highlights potential clinical advantages.

Refining Single-Atom Catalytic Kinetics for Tumor Homologous-Targeted Catalytic Therapy

Single-atom nanozymes (SAzymes) hold significant potential for tumor catalytic therapy, but their effectiveness is often compromised by low catalytic efficiency within tumor microenvironment. This efficiency is mainly influenced by key factors including hydrogen peroxide (H2O2) availability, acidity, and temperature. Simultaneous optimization of these key factors presents a significant challenge for tumor catalytic therapy. In this study, we developed a comprehensive strategy to refine single-atom catalytic kinetics for enhancing tumor catalytic therapy through dual-enzyme-driven cascade reactions. Iridium (Ir) SAzymes with high catalytic activity and natural enzyme glucose oxidase (GOx) were utilized to construct the cascade reaction system. GOx was loaded by Ir SAzymes due to its large surface area. Then, the dual-enzyme-driven cascade reaction system was modified by cancer cell membranes for improving biocompatibility and achieving tumor homologous targeting ability. GOx catalysis reaction could produce abundant H2O2 and lower the local pH, thereby optimizing key reaction-limiting factors. Additionally, upon laser irradiation, Ir SAzymes could raise local temperature, further enhancing the catalytic efficiency of dual-enzyme system. This comprehensive optimization maximized the performance of Ir SAzymes, significantly improving the efficiency of catalytic therapy. Our findings present a strategy of refining single-atom catalytic kinetics for tumor homologous-targeted catalytic therapy.

Recent advances in the use of liquid crystalline nanoparticles for non-small cell lung cancer treatment

INTRODUCTION

Non-small cell lung cancer (NSCLC) continues to pose a considerable health challenge with few therapeutic alternatives. Liquid crystalline nanoparticles (LCN) are nanostructured drug delivery systems made of lipid-based amphiphilic materials that self-assemble into crystalline phases in aqueous environments. LCN have become a promising way to treat NSCLC owing to their specific properties that make them useful for targeted delivery and controlled drug release.

AREAS COVERED

The review provides a brief overview of the use of LCN in the treatment of NSCLC. It explores their composition, fabrication methods, and characterization processes. The article further addresses several nanoparticle-based approaches for the treatment of NSCLC. Ultimately, it underscores the promise of LCNs as a promising drug delivery system for NSCLC and discusses the obstacles and outlook in this field.

EXPERT OPINION

LCN represents a promising frontier in the treatment of NSCLC, offering several specific advantages over conventional therapies. Utilizing their intrinsic self-assembly characteristics, LCN provides meticulous control over drug encapsulation, release kinetics, and cellular absorption, which are crucial for improving therapy success. LCN also has the capability for co-delivery of various drugs, facilitating synergistic therapeutic benefits and addressing multidrug resistance, a prevalent issue in NSCLC treatment.

Unraveling the nexus: Genomic instability and metabolism in cancer

The DNA-damage response (DDR) is a signaling network that enables cells to detect and repair genomic damage. Over the past three decades, inhibiting DDR has proven to be an effective cancer therapeutic strategy. Although cancer drugs targeting DDR have received approval for treating various cancers, tumor cells often develop resistance to these therapies, owing to their ability to undergo energetic metabolic reprogramming. Metabolic intermediates also influence tumor cells' ability to sense oxidative stress, leading to impaired redox metabolism, thus creating redox vulnerabilities. In this review, we summarize recent advances in understanding the crosstalk between DDR and metabolism. We discuss combination therapies that target DDR, metabolism, and redox vulnerabilities in cancer. We also outline potential obstacles in targeting metabolism and propose strategies to overcome these challenges.

The role of glutathione peroxidase 4 in the progression, drug resistance, and targeted therapy of non-small cell lung cancer

Lung cancer is one of the main causes of cancer-related deaths globally, with non-small cell lung cancer (NSCLC) being the most prevalent histological subtype of lung cancer. Glutathione peroxidase 4 (GPX4) is a crucial antioxidant enzyme that plays a role in regulating ferroptosis. It is also involved in a wide variety of biological processes, such as tumor cell growth invasion, migration, and resistance to drugs. This study comprehensively examined the role of GPX4 in NSCLC and investigated the clinical feasibility of targeting GPX4 for NSCLC treatment. We discovered that GPX4 influences the progression of NSCLC by modulating multiple signaling pathways, and that blocking GPX4 can trigger ferroptosis and increase the sensitivity to chemotherapy. As a result, GPX4 represents a prospective therapeutic target for NSCLC. Targeting GPX4 inhibits the development of NSCLC cells and decreases their resistance to treatment.

Mechanisms and Therapeutic Potential of GPX4 in Pain Modulation

Pain, a complex symptom encompassing both sensory and emotional dimensions, constitutes a significant global public health issue. Oxidative stress is a pivotal factor in the complex pathophysiology of pain, with glutathione peroxidase 4 (GPX4) recognized as a crucial antioxidant enzyme involved in both antioxidant defense mechanisms and ferroptosis pathways. This review systematically explores GPX4's functions across various pain models, including neuropathic, inflammatory, low back, and cancer-related pain. Specifically, the focus includes GPX4's physiological roles, antioxidant defense mechanisms, regulation of ferroptosis, involvement in signal transduction pathways, and metabolic regulation. By summarizing current research, we highlight the potential of GPX4-targeted therapies in pain management.

Computational discovery of novel GPX4 inhibitors from herbal sources as potential ferroptosis inducers in cancer therapy

Ferroptosis, a cell death regulation process dependent on iron levels, represents a promising therapeutic target in cancer treatment. However, the scarcity of potent ferroptosis inducers hinders advancement in this area. This study addresses this gap by screening the PubChem database for compounds with favorable ADMET properties to identify potential GPX4 inhibitors. A structure-based virtual screening was conducted to compare binding affinities of selected compounds to that of RSL3. The candidates-isochondrodendrine, hinokiflavone, irinotecan, and ginkgetin-were further analyzed through molecular dynamics (MD) simulations to assess their stability within the GPX4-ligand complexes. The computed binding free energies for RSL3, isochondrodendrine, hinokiflavone, irinotecan and ginkgetin were -80.12, -107.31, -132.03, and -137.52 and -91.11 kJ/mol, respectively, indicating their significantly higher inhibitory effects compared to RSL3. These findings highlight the potential for developing novel GPX4 inhibitors to promote ferroptosis, warranting further experimental validation.

A prospective therapeutic strategy: GPX4-targeted ferroptosis mediators

As a crucial regulator of oxidative homeostasis, seleno-protein glutathione peroxidase 4 (GPX4) represents the primary defense system against ferroptosis, making it a promising target with important clinical application prospects. From the discovery of covalent and allosteric sites in GPX4, substantial advancements in GPX4-targeted small molecules have been made through diverse discovery and design strategies in recent years. Moreover, as an emerging hotspot in drug development, seleno-organic compounds can functionally mimic GPX4 to reduce hydroperoxides. To facilitate the further development of selective ferroptosis mediators as potential pharmaceutical agents, this review comprehensively covers all GPX4-targeted small molecules, including inhibitors, degraders, and activators. In addition, seleno-organic compounds as GPX mimics are also included. We also provide perspectives regarding challenges and future research directions in this field.

Dual Enzyme-Driven Cascade Reactions Modulate Immunosuppressive Tumor Microenvironment for Catalytic Therapy and Immune Activation

Lactate-enriched tumor microenvironment (TME) fosters an immunosuppressive milieu to hamper the functionality of tumor-associated macrophages (TAMs). However, tackling the immunosuppressive effects wrought by lactate accumulation is still a big challenge. Herein, we construct a dual enzyme-driven cascade reaction platform (ILH) with immunosuppressive TME modulation for photoacoustic (PA) imaging-guided catalytic therapy and immune activation. The ILH is composed of iridium (Ir) metallene nanozyme, lactate oxidase (LOx), and hyaluronic acid (HA). The combination of Ir nanozyme and LOx can not only efficiently consume lactate to reverse the immunosuppressive TME into an immunoreactive one by promoting the polarization of TAMs from the M2 to M1 phenotype, thus enhancing antitumor defense, but also alleviate tumor hypoxia as well as induce strong oxidative stress, thus triggering immunogenic cell death (ICD) and activating antitumor immunity. Furthermore, the photothermal performance of Ir nanozyme can strengthen the cascade catalytic ability and endow ILH with a PA response. Based on the changes in PA signals from endogenous molecules, three-dimensional multispectral PA imaging was utilized to track the process of cascade catalytic therapy in vivo. This work provides a nanoplatform for dual enzyme-driven cascade catalytic therapy and immune activation by regulating the immunosuppressive TME.

Red-Light Triggered H-Abstraction Photoinitiators for the Efficient Oxygen-Independent Therapy of Hypoxic Tumors

The clinical application of photodynamic therapy (PDT) is limited by oxygen-dependence and side effects caused by photosensitizer residues. Photoinitiators based on the H-abstraction reaction can address these challenges because they can generate alkyl radical-killing cells independently of oxygen and undergo rapid bleaching following H-abstraction. Nonetheless, the development of photoinitiators for PDT has been impeded by the absence of effective design strategies. Herein, we have developed aryl-ketone substituted cyanine (ACy-R), the first red-light triggered H-abstraction photoinitiators for hypoxic cancer therapy. These ACy-R molecules inherited the near-infrared absorption of cyanine dye, and aryl-ketone modification imparted H-abstraction capability. Experimental and quantum calculations revealed that modifying the electron-withdrawing groups of the aryl (e.g., ACy-5F) improved the contribution of the O atom to the photon excitation process promoting intersystem crossing and H-abstraction ability. Particularly, ACy-5F rapidly penetrated cells and enriched in the endoplasmic reticulum. Even under severe hypoxia, ACy-5F initiated red-light induced H-abstraction with intracellular biomolecules, inducing necroptosis and ferroptosis. Moreover, ACy-5F was degraded after H-abstraction, thus avoiding the side effects of long-term phototoxicity after therapy. This study not only provides a crucial molecular tool for hypoxic tumors therapy, but also presents a promising strategy for the development of multifunctional photosensitizers and photoinitiators.

Research progress on GPX4 targeted compounds

Blocking the System Xc-_ GSH_GPX4 pathway to induce ferroptosis in tumor cells is a novel strategy for cancer treatment. GPX4 serves as the core of the System Xc-/GSH/GPX4 pathway and is a predominant target for inducing ferroptosis in tumor cells. This article summarizes compounds identified in current research that directly target the GPX4 protein, including inhibitors, activators, small molecule degraders, chimeric degraders, and the application of combination therapies with other drugs, aiming to promote further research on the target and related diseases.

Charge-reversal polymeric nanomodulators for ferroptosis-enhanced photodynamic therapy

The clinical application of photodynamic therapy (PDT) has some limitations including poor tumor targeting properties, a high reductive tumor microenvironment, and inefficient activation of single cell death machinery. We herein report pH-sensitive polymeric nanomodulators (NBS-PDMC NPs) for ferroptosis-enhanced photodynamic therapy. NBS-PDMC NPs were constructed using a positively charged type-I photosensitizer (NBS) coordinated with a demethylcantharidin (DMC)-decorated block copolymer via electrostatic interactions. NBS-PDMC NPs had a negative surface charge, which ensures their high stability in bloodstream circulation, while exposure to lysosomal acidic environments reverses their surface charge to positive for tumor penetration and the release of DMC and NBS. Under NIR light irradiation, NBS generated ROS to induce cell damage; in the meantime, DMC inhibited the expression of the GPX4 protein in tumor cells and promoted ferroptosis of tumor cells. This polymer design concept provides some novel insights into smart drug delivery and combinational action to amplify the antitumor effect.

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.

A review on ferroptosis and photodynamic therapy synergism: Enhancing anticancer treatment

Ferroptosis is an iron-dependent programmed cell death modality, which has showed great potential in anticancer treatment. Photodynamic therapy (PDT) is widely used in clinic as an anticancer therapy. PDT combined with ferroptosis-promoting therapy has been found to be a promising strategy to improve anti-cancer therapy efficacy. Fenton reaction in ferroptosis can provide oxygen for PDT, and PDT can produce reactive oxygen species for Fenton reaction to enhance ferroptosis. In this review, we briefly present the importance of ferroptosis in anticancer treatment, mechanism of ferroptosis, researches on PDT induced ferroptosis, and the mechanism of the synergistic effect of PDT and ferroptosis on cancer killing.