Biomimetic Nanophotosensitizer Amplifies Immunogenic Pyroptosis and Triggers Synergistic Cancer Therapy

Targeting pyroptosis for cancer immunotherapy: mechanistic insights and clinical perspectives

Pyroptosis is a distinct form of programmed cell death characterized by the rupture of the cell membrane and robust inflammatory responses. Increasing evidence suggests that pyroptosis significantly affects the tumor microenvironment and antitumor immunity by releasing damage-associated molecular patterns (DAMPs) and pro-inflammatory mediators, thereby establishing it as a pivotal target in cancer immunotherapy. This review thoroughly explores the molecular mechanisms underlying pyroptosis, with a particular focus on inflammasome activation and the gasdermin family of proteins (GSDMs). It examines the role of pyroptotic cell death in reshaping the tumor immune microenvironment (TIME) involving both tumor and immune cells, and discusses recent advancements in targeting pyroptotic pathways through therapeutic strategies such as small molecule modulators, engineered nanocarriers, and combinatory treatments with immune checkpoint inhibitors. We also review recent advances and future directions in targeting pyroptosis to enhance tumor immunotherapy with immune checkpoint inhibitors, adoptive cell therapy, and tumor vaccines. This study suggested that targeting pyroptosis offers a promising avenue to amplify antitumor immune responses and surmount resistance to existing immunotherapies, potentially leading to more efficacious cancer treatments.

Inorganic Nanobiomaterials Boost Tumor Immunotherapy: Strategies and Applications

ConspectusTumor immunotherapy, as a new antitumor method to fight cancer by activating or enhancing the body's own immune system, has been extensively studied and applied in clinical practice. However, as an extremely complex system, tumor heterogeneity and complex immunosuppressive tumor microenvironment (TME) lead to poor immune response rate or secondary drug resistance. The advent of nanotechnology has ushered in a new era for immunotherapy. In particular, inorganic nanomaterials, with their unique physicochemical properties and excellent biocompatibility, are becoming an important tool for enhancing immunotherapy. Inorganic nanomaterials can be used as carriers for immune agents, improving drug delivery efficiency and thereby reducing systemic immunotoxicity and enhancing immune responses. Inorganic nanomaterials also trigger tumor immunogenic cell death (ICD), stimulate antitumor immune responses, and alleviate immunosuppressive TME by increasing oxygen levels, modulating metabolic pathways, and altering the secretion of immunosuppressive cytokines. The synergistic integration of inorganic nanomaterials with immunotherapy adeptly navigates around the constraints of conventional treatments, reducing side effects while concurrently augmenting therapeutic efficacy. In this review, we summarize our recent efforts in the design and synthesis of inorganic nanobiomaterials to enhance the efficacy of tumor immunotherapy. These nanomaterials achieve the desired immune efficacy mainly through four strategies, including inducing ICD, developing tumor nanovaccines, activating pyroptosis, and regulating tumor metabolism, providing beneficial implications for tumor immunotherapy. For one thing, due to the deficiency of ICD effect in single therapy, we mainly developed nanocatalysts that integrate multiple therapeutic functions to play a catalytic role in TME, converting tumor substances or metabolites into therapeutic products in situ, and further enhancing ICD. For another, in order to solve the problems of low antigen loading and therapeutic efficiency of existing adjuvants, several novel multifunctional nanoadjuvants were prepared, which combine high antigen loading and multimode therapeutic function in one, and achieve efficient immune activation. Moreover, to attain strong inflammatory responses and immunogenicity, we engineer pyroptosis adjuvants that selectively induce tumor cell pyroptosis by enhancing intracellular oxidative stress or ion overload. Finally, to reverse the immunosuppressive microenvironment, we developed nanoplatforms that target tumor metabolism, altering the levels of nutrients and metabolites in tumor such as glucose, lactic acid, citric acid, and tryptophan to effectively alter the TME, thereby activating and enhancing the body's immune response. The implementation of these strategies not only improves the therapeutic effect but also reduces the side effects and provides valuable insights and references for the development of novel nanomaterials to assist immunotherapy.

Tumor Treatment by Nano-Photodynamic Agents Embedded in Immune Cell Membrane-Derived Vesicles

Non-invasive phototherapy includes modalities such as photodynamic therapy (PDT) and photothermal therapy (PTT). When combined with tumor immunotherapy, these therapeutic approaches have demonstrated significant efficacy in treating advanced malignancies, thus attracting considerable attention from the scientific community. However, the progress of these therapies is hindered by inherent limitations and potential adverse effects. Recent findings indicate that certain therapeutic strategies, including phototherapy, can induce immunogenic cell death (ICD), thereby opening new avenues for the integration of phototherapy with tumor immunotherapy. Currently, the development of biofilm nanomaterial-encapsulated drug delivery systems has reached a mature stage. Immune cell membrane-encapsulated nano-photosensitizers hold great promise, as they can enhance the tumor immune microenvironment. Based on bioengineering technology, immune cell membranes can be designed according to the tumor immune microenvironment, thereby enhancing the targeting and immune properties of nano-photosensitizers. Additionally, the space provided by the immune cell membrane allows for the co-encapsulation of immunotherapeutic agents and chemotherapy drugs, achieving a synergistic therapeutic effect. At the same time, the timing of photodynamic therapy (PDT) can be precisely controlled to regulate the action timing of both immunotherapeutic and chemotherapy drugs. This article summarizes and analyzes current research based on the aforementioned advancements.

Extracellular vesicles-hitchhiking boosts the deep penetration of drugs to amplify anti-tumor efficacy

Developing drug delivery systems capable of achieving deep tumor penetration is a challenging task, yet there is a significant demand for such systems in cancer treatment. Hitchhiking on tumor-derived extracellular vesicles (EVs) represents a promising strategy for enhancing drug penetration into tumors. However, the limited drug assembly on EVs restricts its further application. Here, we present a novel approach to efficiently attach antitumor drugs to EVs using an engineered cell membrane-based vector. This vector includes the AS1411 aptamer for tumor-specific targeting, the vesicular stomatitis virus glycoprotein (VSV-G) for tumor cell membrane fusion, and a photosensitizer as the therapeutic agent while ensuring optimal drug encapsulation and stability. Upon injection, photosensitizers are firstly transferred to the tumor cell membrane and subsequently piggybacked onto EVs with the inherent secretion process. By hitchhiking with EVs, photosensitizers can be transferred layer by layer deep into the solid tumors. The results suggest that this EVs-hitchhiking strategy enables photosensitizers to penetrate deeply into tumor tissue, thereby enhancing the efficacy of phototherapy. This study offers broad application prospects for delivering drugs deeply into tumor tissues.

Nanomaterials evoke pyroptosis boosting cancer immunotherapy

Cancer immunotherapy is currently a very promising therapeutic strategy for treating tumors. However, its effectiveness is restricted by insufficient antigenicity and an immunosuppressive tumor microenvironment (ITME). Pyroptosis, a unique form of programmed cell death (PCD), causes cells to swell and rupture, releasing pro-inflammatory factors that can enhance immunogenicity and remodel the ITME. Nanomaterials, with their distinct advantages and different techniques, are increasingly popular, and nanomaterial-based delivery systems demonstrate significant potential to potentiate, enable, and augment pyroptosis. This review summarizes and discusses the emerging field of nanomaterials-induced pyroptosis, focusing on the mechanisms of nanomaterials-induced pyroptosis pathways and strategies to activate or enhance specific pyroptosis. Additionally, we provide perspectives on the development of this field, aiming to accelerate its further clinical transition.

Copper-Based biomaterials for anti-tumor therapy: Recent advances and perspectives

Copper, an essential trace element, is integral to numerous metabolic pathways across biological systems. In recent years, copper-based biomaterials have garnered significant interest due to their superior biocompatibility and multifaceted functionalities, particularly in the treatment of malignancies such as sarcomas and cancers. On the one hand, these copper-based materials serve as efficient carriers for a range of therapeutic agents, including chemotherapeutic drugs, small molecule inhibitors, and antibodies, allowing them for precise delivery and controlled release triggered by specific modifications and stimuli. On the other hand, they can induce cell death through mechanisms such as ferroptosis, cuproptosis, apoptosis, and pyroptosis, or inhibit the proliferation and invasion of cancer cells via their outstanding properties. Furthermore, advanced design approaches enable these materials to support tumor imaging and immune activation. Despite this progress, the full scope of their functional capabilities remains to be fully elucidated. This review provides an overview of the anti-tumor functions, underlying mechanisms, and design strategies of copper-based biomaterials, along with their advantages and limitations. The aim is to provide insights into the design, study, and development of novel multifunctional biomaterials, with the ultimate goal of accelerating the clinical application of copper-based nanomaterials in cancer therapy. STATEMENT OF SIGNIFICANCE: This study explores the groundbreaking potential of copper-based biomaterials in cancer therapy, uniquely combining biocompatibility with diverse therapeutic mechanisms such as targeted drug delivery and inhibition of cancer cells through specific cell death pathways. By enhancing tumor imaging and immune activation, copper-based nanomaterials have opened new avenues for cancer treatment. This review examines these multifunctional biomaterials, highlighting their advantages and current limitations while addressing gaps in existing research. The findings aim to accelerate clinical applications of these materials in the field of oncology, providing valuable insights for the design of next-generation copper-based therapies. Therefore, this work is highly relevant to researchers and practitioners focused on innovative cancer treatments.

Nanoformula Design for Inducing Non-Apoptotic Cell Death Regulation: A Powerful Booster for Cancer Immunotherapy

Cancer treatment has witnessed revolutionary advancements marked by the emergence of immunotherapy, specifically immune checkpoint blockade (ICB). However, the inherent low immunogenicity of tumor cells and the intricate immunosuppressive network within the tumor microenvironment (TME) pose significant challenges to the further development of immunotherapy. Nanotechnology has ushered in unprecedented opportunities and vast prospects for tumor immunotherapy. Nevertheless, traditional nano-formulations often rely on inducing apoptosis to kill cancer cells, which encounters the issue of immune silencing, hindering effective tumor immune activation. The non-apoptotic modes of regulated cell death (RCD), including pyroptosis, ferroptosis, autophagy, necroptosis, and cuproptosis, have gradually garnered attention. These non-apoptotic cell death pathways can induce effective immunogenic cell death (ICD), enhancing cancer immunotherapy. This review comprehensively explores advanced nano-formulation design strategies and their applications in enhancing cancer immunotherapy by promoting non-apoptotic RCD in recent years. It also discusses the potential advantages of these strategies in inducing tumor-specific non-apoptotic RCD. By deeply understanding the significance of non-apoptotic RCD in synergistic cancer immunotherapy, this article provides valuable insights for developing more advanced nano-delivery systems that can robustly induce highly immunogenic non-apoptotic modes, offering novel research and development avenues to address the clinical challenges encountered by immunotherapy represented by ICB.

Building of CuO2@Cu-TA@DSF/DHA Nanoparticle Targets MAPK Pathway to Achieve Synergetic Chemotherapy and Chemodynamic for Pancreatic Cancer Cells

Background/Objectives: With the increase of reactive oxygen species (ROS) production, cancer cells can avoid cell death and damage by up-regulating antioxidant programs. Therefore, it will be more effective to induce cell death by using targeted strategies to further improve ROS levels and drugs that inhibit antioxidant programs. Methods: Considering that dihydroartemisinin (DHA) can cause oxidative damage to protein, DNA, or lipids by producing excessive ROS, while, disulfiram (DSF) can inhibit glutathione (GSH) levels and achieve the therapeutic effect by inhibiting antioxidant system and amplifying oxidative stress, they were co-loaded onto the copper peroxide nanoparticles (CuO2) coated with copper tannic acid (Cu-TA), to build a drug delivery system of CuO2@Cu-TA@DSF/DHA nanoparticles (CCTDD NPs). In response to the tumor microenvironment, DHA interacts with copper ion (Cu2+) to produce ROS, and a double (diethylthiocarbamate)-copper (II) (CuET) is generated by the complexation of DSF and Cu2+, which consumes GSH and inhibits antioxidant system. Meanwhile, utilizing the Fenton-like effect induced by the multi-copper mode can achieve ROS storm, activate the MAPK pathway, and achieve chemotherapy (CT) and chemodynamic (CDT). Results: Taking pancreatic cancer cell lines PANC-1 and BxPC-3 as the research objects, cell line experiments in vitro proved that CCTDD NPs exhibit efficient cytotoxicity on cancer cells. Conclusions: The CCTDD NPs show great potential in resisting pancreatic cancer cells and provides a simple strategy for designing powerful metal matrix composites.

Near-Infrared-II-Activated Transition Metal(II)-Coordinated Ligand Radical Primes Robust Anticancer Immunity

Photoactivatable metallodrugs combining tumor cell eradication and immune stimulation hold immense promise for targeted cancer therapy. However, limitations such as oxygen dependence, narrow visible light responsiveness, and poor immunogenicity hinder their efficacy in deep solid tumors with hypoxic and immunosuppressive microenvironments. Herein, we present a novel design strategy for transition metal(II)-coordinated ligand radicals exhibiting intense near-infrared-II (NIR-II) absorption, unique endoplasmic reticulum-targeting capability, and oxygen-independent photothermal performance, effectively addressing these constraints. Proof-of-concept results demonstrate the potent efficacy of our cobalt(II)-coordinated ligand radical (BPDP-Co) in inducing highly immunogenic pyroptosis in tumor cells under both normoxic and severe hypoxic conditions upon 1064 nm laser irradiation. This NIR-II activation triggers the release of damage-associated molecular patterns (DAMPs) and proinflammatory cytokines, fueling a robust antitumor immune response. In vivo studies demonstrate that treatment with BPDP-Co/NIR-II significantly inhibited 4T1 tumor growth in BALB/c mice with a high inhibitory rate of 85.7%, highlighting its therapeutic potential in tumor immunotherapy.

Controllable All-in-One Biomimetic Hollow Nanoscaffold Initiating Pyroptosis-Mediated Antiosteosarcoma Targeted Therapy and Bone Defect Repair

Pyroptosis has gained attention for its potential to reinvigorate the immune system within the tumor microenvironment. However, current approaches employing pyroptosis inducers suffer from limitations. They primarily rely on single agents, lack precise targeting, and potentially disrupt the intricate bone formation microenvironment, hindering local repair of tumor-induced bone defects. Therefore, a therapeutic strategy is urgently needed that can effectively trigger pyroptosis while simultaneously promoting bone regeneration. This research introduces an all-in-one construct designed to address these limitations. It combines a cell-camouflaged shell with an autosynergistic reactive oxygen species (ROS) generating polymer. This construct incorporates a hollow core of manganese dioxide (HMnO2) embedded with the photosensitizer IR780 and disguised by the cell membrane of an M1 macrophage. The M1 macrophage membrane grants the construct stealth-like properties, enabling it to accumulate selectively at the tumor site. Upon laser irradiation, IR780 acts as an exogenous trigger for ROS generation while simultaneously converting the light energy into heat. Additionally, the hollow structure of HMnO2 serves as an efficient carrier for IR780. Furthermore, Mn4+ ions released from HMnO2 deplete glutathione (GSH) within the tumor, further amplifying ROS production. This synergistic cascade ultimately culminates in pyroptosis induction through caspase-3-mediated cleavage of gasdermin E (GSDME) upon laser activation. Meanwhile, the depletion of GSH by HMnO2 within the tumor microenvironment (TME) leads to the generation of Mn2+ ions. These Mn2+ ions establish a supportive milieu, which promotes the transformation of bone marrow mesenchymal stem cells (BMSCs) into mature bone cells. This, in turn, promotes the repair of bone defects in rat femurs. Our findings strongly indicate that pyroptosis may be a strategy for osteosarcoma treatment, which presents a robust and versatile approach for targeted therapy and tissue regeneration in this patient population.

Engineering Bimetallic Polyphenol for Mild Photothermal Osteosarcoma Therapy and Immune Microenvironment Remodeling by Activating Pyroptosis and cGAS-STING Pathway

The immunosuppressive tumor microenvironment (ITME) of osteosarcoma (OS) poses a significant obstacle to the efficacy of existing immunotherapies. Despite the attempt of novel immune strategies such as immune checkpoint inhibitors and tumor vaccines, their effectiveness remains suboptimal due to the inherent difficulty in mitigating ITME simultaneously from both the tumor and immune system. The promotion of anti-tumor immunity through the induction of immunogenic cell death and activation of the cGAS-STING pathway has emerged as potential strategies to counter the ITME and stimulate systemic antitumor immune responses. Here, a bimetallic polyphenol-based nanoplatform (Mn/Fe-Gallate nanoparticles coated with tumor cell membranes is presented, MFG@TCM) which combines with mild photothermal therapy (PTT) for reversing ITME via simultaneously inducing pyroptosis in OS cells and activating the cGAS-STING pathway in dendritic cells (DCs). The immunostimulatory pathways, through the syngeneic effect, exerted a substantial positive impact on promoting the secretion of damage-associated molecular patterns (DAMPs) and proinflammatory cytokines, which favors remodeling the immune microenvironment. Consequently, effector T cells led to a notable antitumor immune response, effectively inhibiting the growth of both primary and distant tumors. This study proposes a new method for treating OS using mild PTT and immune mudulation, showing promise in overcoming current treatment limitations.

Research progress on the effect of pyroptosis on the occurrence, development, invasion and metastasis of colorectal cancer

Pyroptosis is a type of programmed cell death mediated by gasdermines (GSDMs). The N-terminal domain of GSDMs forms pores in the plasma membrane, causing cell membrane rupture and the release of cell contents, leading to an inflammatory response and mediating pyrodeath. Pyroptosis plays an important role in inflammatory diseases and malignant tumors. With the further study of pyroptosis, an increasing number of studies have shown that the pyroptosis pathway can regulate the tumor microenvironment and antitumor immunity of colorectal cancer and is closely related to the occurrence, development, treatment and prognosis of colorectal cancer. This review aimed to explore the molecular mechanism of pyroptosis and the role of pyroptosis in the occurrence, development, treatment and prognosis of colorectal cancer (CRC) and to provide ideas for the clinical diagnosis and treatment of CRC.

Nanoparticles in tumor microenvironment remodeling and cancer immunotherapy

Cancer immunotherapy and vaccine development have significantly improved the fight against cancers. Despite these advancements, challenges remain, particularly in the clinical delivery of immunomodulatory compounds. The tumor microenvironment (TME), comprising macrophages, fibroblasts, and immune cells, plays a crucial role in immune response modulation. Nanoparticles, engineered to reshape the TME, have shown promising results in enhancing immunotherapy by facilitating targeted delivery and immune modulation. These nanoparticles can suppress fibroblast activation, promote M1 macrophage polarization, aid dendritic cell maturation, and encourage T cell infiltration. Biomimetic nanoparticles further enhance immunotherapy by increasing the internalization of immunomodulatory agents in immune cells such as dendritic cells. Moreover, exosomes, whether naturally secreted by cells in the body or bioengineered, have been explored to regulate the TME and immune-related cells to affect cancer immunotherapy. Stimuli-responsive nanocarriers, activated by pH, redox, and light conditions, exhibit the potential to accelerate immunotherapy. The co-application of nanoparticles with immune checkpoint inhibitors is an emerging strategy to boost anti-tumor immunity. With their ability to induce long-term immunity, nanoarchitectures are promising structures in vaccine development. This review underscores the critical role of nanoparticles in overcoming current challenges and driving the advancement of cancer immunotherapy and TME modification.

Engineering materials for pyroptosis induction in cancer treatment

Cancer remains a significant global health concern, necessitating the development of innovative therapeutic strategies. This research paper aims to investigate the role of pyroptosis induction in cancer treatment. Pyroptosis, a form of programmed cell death characterized by the release of pro-inflammatory cytokines and the formation of plasma membrane pores, has gained significant attention as a potential target for cancer therapy. The objective of this study is to provide a comprehensive overview of the current understanding of pyroptosis and its role in cancer treatment. The paper discusses the concept of pyroptosis and its relationship with other forms of cell death, such as apoptosis and necroptosis. It explores the role of pyroptosis in immune activation and its potential for combination therapy. The study also reviews the use of natural, biological, chemical, and multifunctional composite materials for pyroptosis induction in cancer cells. The molecular mechanisms underlying pyroptosis induction by these materials are discussed, along with their advantages and challenges in cancer treatment. The findings of this study highlight the potential of pyroptosis induction as a novel therapeutic strategy in cancer treatment and provide insights into the different materials and mechanisms involved in pyroptosis induction.

Advancing Precision: A Controllable Self-Synergistic Nanoplatform Initiating Pyroptosis-Based Immunogenic Cell Death Cascade for Targeted Tumor Therapy

Heterogeneity of the tumor microenvironment (TME) is primarily responsible for ineffective tumor treatment and uncontrolled tumor progression. Pyroptosis-based immunogenic cell death (ICD) therapy is an ideal strategy to overcome TME heterogeneity and obtain a satisfactory antitumor effect. However, the efficiency of current pyroptosis therapeutics, which mainly depends on a single endogenous or exogenous stimulus, is limited by the intrinsic pathological features of malignant cells. Thus, it is necessary to develop a synergistic strategy with a high tumor specificity and modulability. Herein, a synergistic nanoplatform is constructed by combining a neutrophil camouflaging shell and a self-synergistic reactive oxygen species (ROS) supplier-loaded polymer. The covered neutrophil membranes endow the nanoplatform with stealthy properties and facilitate sufficient tumor accumulation. Under laser irradiation, the photosensitizer (indocyanine green) exogenously triggers ROS generation and converts the laser irradiation into heat to upregulate NAD(P)H:quinone oxidoreductase 1, which further catalyzes β-Lapachone to self-produce sufficient endogenous ROS, resulting in amplified ICD outcomes. The results confirm that the continuously amplified ROS production not only eliminates the primary tumor but also concurrently enhances gasdermin E-mediated pyroptosis, initiates an ICD cascade, re-educates the heterogeneous TME, and promotes a systemic immune response to suppress distant tumors. Overall, this self-synergistic nanoplatform provides an efficient and durable method for redesigning the immune system for targeted tumor inhibition.