Emerging photodynamic nanotherapeutics for inducing immunogenic cell death and potentiating cancer immunotherapy

Hydroxyethyl starch-based self-reinforced nanomedicine inhibits both glutathione and thioredoxin antioxidant pathways to boost reactive oxygen species-powered immunotherapy

The adaptive antioxidant systems of tumor cells, predominantly glutathione (GSH) and thioredoxin (TRX) networks, severely impair photodynamic therapy (PDT) potency and anti-tumor immune responses. Here, a multistage redox homeostasis nanodisruptor (Phy@HES-IR), integrated by hydroxyethyl starch (HES)-new indocyanine green (IR820) conjugates with physcion (Phy), an inhibitor of the pentose phosphate pathway (PPP), is rationally designed to achieve PDT primed cancer immunotherapy. In this nanodisruptor, Phy effectively depletes intracellular GSH of tumor cells by inhibiting 6-phosphogluconate dehydrogenase (6PGD) activity. Concurrently, it is observed for the first time that the modified IR820-NH2 molecule not only exerts PDT action but also interferes with TRX antioxidant pathway by inhibiting thioredoxin oxidase (TRXR) activity. The simultaneous weakening of two major antioxidant pathways of tumor cells is favorable to maximize the PDT efficacy induced by HES-IR conjugates. By virtue of the excellent protecting ability of the plasma expander HES, Phy@HES-IR can remain stable in the blood circulation and efficiently enrich in the tumor region. Consequently, PDT and metabolic modulation synergistically induced immunogenic cell death, which not only suppressed primary tumors but also stimulated potent anti-tumor immunity to inhibit the growth of distant tumors in 4T1 tumor-bearing mice.

Emerging role of immunogenic cell death in cancer immunotherapy: Advancing next-generation CAR-T cell immunotherapy by combination

Immunogenic cell death (ICD) is a stress-driven form of regulated cell death (RCD) in which dying tumor cells' specific signaling pathways are activated to release damage-associated molecular patterns (DAMPs), leading to the robust anti-tumor immune response as well as a reversal of the tumor immune microenvironment from "cold" to "hot". Chimeric antigen receptor (CAR)-T cell therapy, as a landmark in anti-tumor immunotherapy, plays a formidable role in hematologic malignancies but falls short in solid tumors. The Gordian knot of CAR-T cells for solid tumors includes but is not limited to, tumor antigen heterogeneity or absence, physical and immune barriers of tumors. The combination of ICD induction therapy and CAR-T cell immunotherapy is expected to promote the intensive use of CAR-T cell in solid tumors. In this review, we summarize the characteristics of ICD, stress-responsive mechanism, and the synergistic effect of various ICD-based therapies with CAR-T cells to effectively improve anti-tumor capacity.

A dual-prodrug nanogel combining Vorinostat and Pyropheophorbide a for a high efficient photochemotherapy

The challenges posed by intractable relapse and metastasis in cancer treatment have led to the development of various forms of photodynamic therapy (PDT). However, traditional drug delivery systems, such as virus vectors, liposomes, and polymers, often suffer from issues like desynchronized drug release, carrier instability, and drug leakage during circulation. To address these problems, we have developed a dual-prodrug nanogel (PVBN) consisting of Pyro (Pyropheophorbide a) and SAHA (Vorinostat) bound to BSA (Bovine Serum Albumin), which facilitates synchronous and spontaneous drug release in situ within the lysosome. Detailed results indicate that PVBN-treated tumor cells exhibit elevated levels of ROS and Acetyl-H3, leading to necrosis, apoptosis, and cell cycle arrest, with PDT playing a dominant role in the synergistic therapeutic effect. Furthermore, the anti-tumor efficacy of PVBN was validated in melanoma-bearing mice, where it significantly inhibited tumor growth and pulmonary metastasis. Overall, our dual-prodrug nanogel, formed by the binding of SAHA and Pyro to BSA and releasing drugs within the lysosome, represents a novel and promising strategy for enhancing the clinical efficacy of photochemotherapy.

Endoplasmic reticulum-targeted iridium(III) photosensitizer induces pyroptosis for augmented tumor immunotherapy

An ideal tumor treatment strategy involves therapeutic approaches that can enhance the immunogenicity of the tumor microenvironment while simultaneously eliminating the primary tumor. A cholic acid-modified iridium(III) (Ir3) photosensitizer, targeted to the endoplasmic reticulum (ER), has been reported to exhibit potent type I and type II photodynamic therapeutic effects against triple-negative breast cancer (MDA-MB-231). This photosensitizer induces pyroptotic cell death mediated by gasdermin E (GSDME) through photodynamic means and enhances tumor immunotherapy. Mechanistic studies have revealed that complex Ir3 induces characteristics of damage-related molecular patterns (DAMPs) in MDA-MB-231 breast cancer cells under light conditions. These include cell-surface calreticulin (CRT) eversion, extracellular high mobility group box 1 (HMGB1) and ATP release, accompanied by ER stress and increased reactive oxygen species (ROS). Consequently, complex Ir3 promotes dendritic cell maturation and antigen presentation under light conditions, fully activates T cell-dependent immune response in vivo, and ultimately eliminates distant tumors while destroying primary tumors. In conclusion, immune regulation and targeted intervention mediated by metal complexes represent a new and promising approach to tumor therapy. This provides an effective strategy for the development of combined targeted therapy and immunotherapy.

Erythrocyte Membrane Camouflaged Nanotheranostics for Optical Molecular Imaging-Escorted Self-Oxygenation Photodynamic Therapy

Hypoxic tumor microenvironment (TME) hampers the application of oxygen (O2)-dependent photodynamic therapy (PDT) in solid tumors. To address this problem, a biomimetic nanotheranostics (named MMCC@EM) is developed for optical molecular imaging-escorted self-oxygenation PDT. MMCC@EM is synthesized by encapsulating chlorin e6 (Ce6) and catalase (CAT) in metal-organic framework (MOF) nanoparticles with erythrocyte membrane (EM) camouflage. Based on the biomimetic properties of EM, MMCC@EM efficiently accumulates in tumor tissues. The enriched MMCC@EM achieves TME-activatable drug release, thereby releasing CAT and Ce6, and this process can be monitored through fluorescence (FL) imaging. In addition, endogenous hydrogen peroxide (H2O2) will be decomposed by CAT to produce O2, which can be reflected by the measurement of intratumoral oxygen concentration using photoacoustic (PA) imaging. Such self-oxygenation nanotheranostics effectively mitigate tumor hypoxia and improve the generation of singlet oxygen (1O2). The 1O2 disrupts mitochondrial function and triggers caspase-3-mediated cellular apoptosis. Furthermore, MMCC@EM triggers immunogenic cell death (ICD) effect, leading to an increased infiltration of cytotoxic T lymphocytes (CTLs) into tumor tissues. As a result, MMCC@EM exhibits good therapeutic effects in 4T1-tumor bearing mice under the navigation of FL/PA duplex imaging.

Biomimetic gold nanocages incorporating copper-human serum albumin for tumor immunotherapy via cuproptosis-lactate regulation

Cancer immunotherapy remains a significant challenge due to insufficient proliferation of immune cells and the sturdy immunosuppressive tumor microenvironment. Herein, we proposed the hypothesis of cuproptosis-lactate regulation to provoke cuproptosis and enhance anti-tumor immunity. For this purpose, copper-human serum albumin nanocomplex loaded gold nanocages with bacterial membrane coating (BAu-CuNCs) were developed. The targeted delivery and disassembly of BAu-CuNCs in tumor cells initiated a cascade of reactions. Under near infrared (NIR) laser irradiation, the release of copper-human serum albumin (Cu-HSA) was enhanced that reacted with intratumoral glutathione (GSH) via a disulfide exchange reaction to liberate Cu2+ ions and exert cuproptosis. Subsequently, the cuproptosis effect triggered immunogenic cell death (ICD) in tumor by the release of damage associated molecular patterns (DAMPs) to realize anti-tumor immunity via robust production of cytotoxic T cells (CD8+) and helper T cells (CD4+). Meanwhile, under NIR irradiation, gold nanocages (AuNCs) promoted excessive reactive oxygen species (ROS) generation that played a primary role in inhibiting glycolysis, reducing the lactate and ATP level. The combine action of lower lactate level, ATP reduction and GSH depletion further sensitized the tumor cells to cuproptosis. Also, the lower lactate production led to the significant blockage of immunosuppressive T regulatory cells (Tregs) and boosted the anti-tumor immunity. Additionally, the effective inhibition of breast cancer metastasis to the lungs enhanced the anti-tumor therapeutic impact of BAu-CuNCs + NIR treatment. Hence, BAu-CuNCs + NIR concurrently induced cuproptosis, ICD and hindered lactate production, leading to the inhibition of tumor growth, remodeling of the immunosuppressive tumor microenvironment and suppression of lung metastasis. Therefore, leveraging cuproptosis-lactate regulation, this approach presents a novel strategy for enhanced tumor immunotherapy.

Photoswitchable dynamics and RNAi synergist with tailored interface and controlled release reprogramming tumor immunosuppressive niche

Immunosuppressive tumor microenvironment (ITM) severely limited the efficacy of immunotherapy against triple-negative breast cancer (TNBC). Herein, Apt-LPR, a light-activatable photodynamic therapy (PDT)/RNAi immune synergy-enhancer was constructed by co-loading miR-34a and photosensitizers in cationic liposomes (in phase III clinical trial). Interestingly, the introduction of tumor-specific aptamers creates a special "Liposome-Aptamer-Target" interface, where the aptamers are initially in a "lying down" state but transform to "standing up" after target binding. The interfacing mechanism was elaborately revealed by computational and practical experiments. This unique interface endowed Apt-LPR with neutralized surface potential of cationic liposomes to reduce non-specific cytotoxicity, enhanced DNase resistance to protect aptamers, and preserved target-binding ability for selective drug delivery. Upon near-infrared irradiation, the generated reactive oxygen species would oxidize unsaturated phospholipids to destabilize both liposomes and lysosomes, realizing stepwise lysosomal escape of miR-34a for tumor cell apoptosis and downregulation of PD-L1 to suppress immune escape. Together, tumor-associated antigens released from PDT-damaged mitochondria and endoplasmic reticulum could activate the suppressive immune cells to establish an "immune hot" milieu. The collaborative immune-enhancing strategy effectively aroused systemic antitumor immunity and inhibited primary and distal tumor progression as well as lung metastasis in 4T1 xenografted mouse models. The photo-controlled drug release and specific tumor-targeting capabilities of Apt-LPR were also visualized in MDA-MB-231 xenografted zebrafish models. Therefore, this photoswitchable PDT/RNAi immune stimulator offered a powerful approach to reprogramming ITM and reinforcing cancer immunotherapy efficacy.

Multifunctional single-component photosensitizers as metal-free ferroptosis inducers for enhanced photodynamic immunotherapy

Immunotherapy can enhance primary tumor efficacy, restrict distant growth, and combat lung metastasis. Unfortunately, it remains challenging to effectively activate the immune response. Here, tertiary butyl, methoxy, and triphenylamine (TPA) were utilized as electron donors to develop multifunctional photosensitizers (PSs). CNTPA-TPA, featuring TPA as the donor (D) and cyano as the acceptor (A), excelled in reactive oxygen species (ROS) generation due to its smaller singlet-triplet energy gap (ΔES-T) and larger spin-orbit coupling constant (SOC). Additionally, cyano groups reacted with glutamate (Glu) and glutathione (GSH), reducing intracellular GSH levels. This not only enhanced PDT efficacy but also triggered redox dyshomeostasis-mediated ferroptosis. The positive effects of photodynamic therapy (PDT) and ferroptosis promoted immunogenic cell death (ICD) and immune activation. By further combining anti-programmed cell death protein ligand-1 (anti-PD-L1) antibody, the powerful treatments of ferroptosis-assisted photodynamic immunotherapy significantly eradicated the primary tumors, inhibited the growth of distant tumors, and suppressed lung metastasis. In this study, a three-pronged approach was realized by single-component CNTPA-TPA, which simultaneously served as metal-free ferroptosis inducers, type-I photosensitizers, and immunologic adjuvants for near-infrared fluorescence imaging (NIR FLI)-guided multimodal phototheranostics of tumor. STATEMENT OF SIGNIFICANCE: (1) CNTPA-TPA shared the smallest singlet-triplet energy gap and the largest spin-orbit coupling constant, which boosted intersystem crossing for efficient type-I photodynamic therapy (PDT); (2) Special reactions between cyano groups with glutamate and glutathione in mild conditions restricted the biosynthesis of intracellular GSH. GSH-depletion efficiently induced glutathione peroxidase 4 inactivation and lipid peroxide, resulting in ferroptosis of tumor cells; (3) The combination treatments of ferroptosis-assisted photodynamic immunotherapy induced by single-component CNTPA-TPA with the participation of anti-PD-L1 antibody resulted in increased T-cell infiltration and profound suppression of both primary and distant tumor growth, as well as lung metastasis.

Light-responsive functional nanomaterials as pioneering therapeutics: a paradigm shift to combat age-related disorders

Aging, marked by dysregulated cellular systems, gives rise to a spectrum of age-related disorders, including neurodegeneration, atherosclerosis, immunosenescence, and musculoskeletal issues. These conditions contribute significantly to the global disease burden, posing challenges to health span and economic resources. Current therapeutic approaches, although diverse in mechanism, often fall short in targeting the underlying cellular pathologies. They fail to address the issues compounded by altered pharmacokinetics in the elderly. Nanotechnology emerges as a transformative solution, offering tissue-specific targeted therapies through nanoparticles. Functional nanomaterials (FNMs) respond to internal or external stimuli, with light-responsive nanomaterials gaining prominence. Harnessing the benefits of deep tissue penetration and ease of manipulation particularly in the near-infrared spectrum, light-responsive FNMs present innovative strategies for age-related comorbidities. This review comprehensively summarizes the potential of light-responsive FNM-based approaches for targeting cellular environments in age-related disorders, and also emphasizes the advantages over traditional treatment modalities. Specifically, it focuses on the development of various classes of light-responsive functional nanomaterials including plasmonic nanomaterials, nanomaterials as carriers, upconversion nanomaterials, 2D nanomaterials, transition metal oxide and dichalcogenide nanomaterials and carbon-based nanomaterials against age related diseases. We foresee that such advanced developments in the field of nanotechnology could provide a new hope for clinical diagnosis and treatment of age-related disorders.

Reactive oxygen species of tumor microenvironment: Harnessing for immunogenic cell death

The tumor microenvironment (TME) is a dynamic and complex system that undergoes continuous changes in its network architecture, notably affecting redox homeostasis. These alterations collectively shape a diverse ecosystem actively supporting tumor progression by influencing the cellular and molecular components of the TME. Despite the remarkable clinical advancements in cancer immunotherapy, its spectrum of clinical utility is limited by the altered TME and inadequate tumor immunogenicity. Recent studies have revealed that some conventional and targeted therapy strategies can augment the efficacy of immunotherapy even in patients with less immunogenic solid tumors. These strategies provoke immunogenic cell death (ICD) through the ROS-dependent liberation of damage-associated molecular patterns (DAMPs). These DAMPs recognize and bind with Pattern Recognition Receptors (PRRs) on immune cells, activating and maturing defense cells, ultimately leading to a robust antitumor immune response. The present review underscores the pivotal role of redox homeostasis in orchestrating the transition of TME from a cold to a hot phenotype and the ROS-ICD axis in immune response induction. Additionally, it provides up-to-date insights into strategies that leverage ROS generation to induce ICD. The comprehensive analysis aims to develop ROS-based effective cancer immunotherapies for less immunogenic tumors.

Photothermal Particle-Loaded Panax Notoginseng Polysaccharide Cryogels As Personalized Tumor Vaccines

Combination immunotherapy is being increasingly explored for cancer treatment, leading to various vector materials for the codelivery of immune agents and drugs. However, current tumor vaccines exhibit poor immunogenicity, severely compromising their therapeutic efficacy. Herein, an injectable hydrogel was developed based on dopamine (DA) and Panax notoginseng polysaccharide (PNPS) loaded with hair microparticles (HMPs) to enhance the immunogenicity of tumor vaccines. Photothermal effects of incorporated HMPs can trigger immunogenic cancer cell death and the release of abundant autologous tumor antigens, which are captured by catechol groups. Concomitant breakdown of PNPS recruits and activates dendritic cells (DCs). The macroporous structure of cryogels allows immune cell infiltration and interaction with antigens adsorbed on PNPS and DA cryogels (PD cryogels), thereby provoking potent cytotoxic T-cell responses. Hence, PD cryogels enabling cell infiltration and accelerated DC maturation may serve as a therapeutic vaccination platform against cancer.

2D nanomaterials-based delivery systems and their potentials in anticancer synergistic photo-immunotherapy

As the field of cancer therapeutics evolves, integrating two-dimensional (2D) nanomaterials with photo-immunotherapy has emerged as a promising approach with significant potential to augment cancer treatment efficacy. These 2D nanomaterials include graphene-based 2D nanomaterials, 2D MXenes, 2D layered double hydroxides, black phosphorus nanosheets, 2D metal-organic frameworks, and 2D transition metal dichalcogenides. They exhibit high load capacities, multiple functionalization pathways, optimal biocompatibility, and physiological stability. Predominantly, they function as anti-tumor delivery systems, amalgamating diverse therapeutic modalities, most notably phototherapy and immunotherapy, and the former is a recognized non-invasive treatment modality, and the latter represents the most promising anti-cancer strategy presently accessible. Thus, integrating phototherapy and immunotherapy founded on 2D nanomaterials unveils a novel paradigm in the war against cancer. This review delineates the latest developments in 2D nanomaterials as delivery systems for synergistic photo-immunotherapy in cancer treatment. We elaborate on the burgeoning realm of photo-immunotherapy, exploring the interplay between phototherapy and enhanced immune cells, immune response modulation, or immunosuppressive tumor microenvironments. Notably, the strategies to augment photo-immunotherapy have also been discussed. Finally, we discuss the challenges and future perspectives of these 2D nanomaterials in photo-immunotherapy.

Mesoporous polydopamine Targeting CDK4/6 Inhibitor toward Brilliant Synergistic Immunotherapy of Breast Cancer

Immunotherapy utilizing anti-PD-L1 blockade has achieved dramatic success in clinical breast cancer management but is often hampered by the limited immune response. Increasing evidence shows that immunogenic cell death (ICD) recently arises as a promising strategy for enlarging tumor immunogenicity and eliciting systemic anti-tumor immunity effectively. However, developing simple but versatile, highly efficient but low-toxic, biosafe, and clinically available transformed ICD inducers remains a huge demand and is highly desirable. Herein, a multifunctional ICD inducer is purposefully developed A6-MPDA@PAL by integrating photothermal therapy (PTT) nanoplatforms mesoporous polydopamine (MPDA), CDK4/6 inhibitor palbociclib (PAL), and CD44-specific targeting A6 peptide in a simple way for augmenting the immune antitumor efficacy of anti-PD-L1 therapy. Remarkably, the light-inducible nanoplatforms exhibit multiple favorable therapeutic features ensuring a superior and biosafe PTT/chemotherapy efficacy. Together with stronger accumulative ICD induction, single administration of A6-MPDA@PAL can trigger robust systemic antitumor immunity and abscopal effect with the assistance of anti-PD-L1 blockade by fascinating the intratumoral infiltration of T lymphocytes and reversing the immunosuppressive tumor microenvironment simultaneously, therapy achieving brilliant synergistic immunotherapy with effective tumor ablation. This study presents a simple and smart ICD inducer opening up attractive clinical possibilities for reinforcing the anti-PD-L1 therapy against breast cancer.

Recent Advances of Engineered Cell Membrane-Based Nanotherapeutics to Combat Inflammatory Diseases

An immune reaction known as inflammation serves as a shield from external danger signals, but an overactive immune system may additionally lead to tissue damage and even a variety of inflammatory disorders. By inheriting biological functionalities and serving as both a therapeutic medication and a drug carrier, cell membrane-based nanotherapeutics offer the potential to treat inflammatory disorders. To further strengthen the anti-inflammatory benefits of natural cell membranes, researchers alter and optimize the membranes using engineering methods. This review focuses on engineered cell membrane-based nanotherapeutics (ECMNs) and their application in treating inflammation-related diseases. Specifically, this article discusses the methods of engineering cell membranes for inflammatory diseases and examines the progress of ECMNs in inflammation-targeted therapy, inflammation-neutralizing therapy, and inflammation-immunomodulatory therapy. Additionally, the article looks into the perspectives and challenges of ECMNs in inflammatory treatment and offers suggestions as well as guidance to encourage further investigations and implementations in this area.

A Tumor Environment-Activated Photosensitized Biomimetic Nanoplatform for Precise Photodynamic Immunotherapy of Colon Cancer

Aggressive nature of colon cancer and current imprecise therapeutic scenarios simulate the development of precise and effective treatment strategies. To achieve this, a tumor environment-activated photosensitized biomimetic nanoplatform (PEG2000-SiNcTI-Ph/CpG-ZIF-8@CM) is fabricated by encapsulating metal-organic framework loaded with developed photosensitizer PEG2000-SiNcTI-Ph and immunoadjuvant CpG oligodeoxynucleotide within fusion cell membrane expressing programmed death protein 1 (PD-1) and cluster of differentiation 47 (CD47). By stumbling across, systematic evaluation, and deciphering with quantum chemical calculations, a unique attribute of tumor environment (low pH plus high concentrations of adenosine 5'-triphosphate (ATP))-activated photodynamic effect sensitized by long-wavelength photons is validated for PEG2000-SiNcTI-Ph/CpG-ZIF-8@CM, advancing the precision of cancer therapy. Moreover, PEG2000-SiNcTI-Ph/CpG-ZIF-8@CM evades immune surveillance to target CT26 colon tumors in mice mediated by CD47/signal regulatory proteins α (SIRPα) interaction and PD-1/programmed death ligand 1 (PD-L1) interaction, respectively. Tumor environment-activated photodynamic therapy realized by PEG2000-SiNcTI-Ph/CpG-ZIF-8@CM induces immunogenic cell death (ICD) to elicit anti-tumor immune response, which is empowered by enhanced dendritic cells (DC) uptake of CpG and PD-L1 blockade contributed by the nanoplatform. The photodynamic immunotherapy efficiently combats primary and distant CT26 tumors, and additionally generates immune memory to inhibit tumor recurrence and metastasis. The nanoplatform developed here provides insights for the development of precise cancer therapeutic strategies.

Black Phosphorus Quantum Dot Loaded Bioinspired Nanoplatform Synergized with aPD-L1 for Multimode Cancer Immunotherapy

Efforts to prolong the blood circulation time and bypass immune clearance play vital roles in improving the therapeutic efficacy of nanoparticles (NPs). Herein, a multifunctional nanoplatform (BPP@RTL) that precisely targets tumor cells is fabricated by encapsulating ultrasmall phototherapeutic agent black phosphorus quantum dot (BPQD), chemotherapeutic drug paclitaxel (PTX), and immunomodulator PolyMetformin (PM) in hybrid membrane-camouflaged liposomes. Specifically, the hybrid cell membrane coating derived from the fusion of cancer cell membrane and red blood cell membrane displays excellent tumor targeting efficiency and long blood circulation property due to the innate features of both membranes. After collaboration with aPD-L1-based immune checkpoint blockade therapy, a boosted immunotherapeutic effect is obtained due to elevated dendritic cell maturation and T cell activation. Significantly, laser-irradiated BPP@RTL combined with aPD-L1 effectively eliminates primary tumors and inhibits lung metastasis in 4T1 breast tumor model, offering a promising treatment plan to develop personalized antitumor strategy.

Endoplasmic Reticulum-Targeting Self-Assembly Nanosheets Promote Autophagy and Regulate Immunosuppressive Tumor Microenvironment for Efficient Photodynamic Immunotherapy

The poor efficiency and low immunogenicity of photodynamic therapy (PDT), and the immunosuppressive tumor microenvironment (ITM) lead to tumor recurrence and metastasis. In this work, TCPP-TER-Zn@RSV nanosheets (TZR NSs) that co-assembled from the endoplasmic reticulum (ER)-targeting photosensitizer TCPP-TER-Zn nanosheets (TZ NSs for short) and the autophagy promoting and indoleamine-(2, 3)-dioxygenase (IDO) inhibitor-like resveratrol (RSV) are fabricated to enhance antitumor PDT. TZR NSs exhibit improved therapeutic efficiency and amplified immunogenic cancer cell death (ICD) by ER targeting PDT and ER autophagy promotion. TZR NSs reversed the ITM with an increase of CD8+ T cells and reduce of immunosuppressive Foxp3 regulatory T cells, which effectively burst antitumor immunity thus clearing residual tumor cells. The ER-targeting TZR NSs developed in this paper presents a simple but valuable reference for high-efficiency tumor photodynamic immunotherapy.

Potentiating Immunogenic Cell Death in Cold Tumor with Functional Living Materials of FeAu-Methylene Blue Composites

Low immunogenicity, absence of tumor-infiltrating lymphocytes and immunosuppressive microenvironment of immune cold tumors are the main bottlenecks leading to unfavorable prognosis. Here, an integrated tumor bioimaging and multimodal therapeutic strategy is developed, which converts immune cold into hot by modulating oxidative stress levels, enhancing photo-killing efficacy, inducing immunogenic cell death and inhibiting the immune checkpoint. On that occasion, the unique tumor microenvironment can be harnessed to biosynthesize in situ self-assembly iron complexes and fluorescent gold nanoclusters from metal ions Fe(II) and Au(III) for active targeting and real-time visualization of the tumors, simultaneously regulating reactive oxygen species levels within tumors via peroxidase-like activity. Furthermore, methylene blue (MB)-mediated photodynamic therapy promotes the release of damage-associated molecular patterns (DAMPs), which acts as in situ tumor vaccine and further induces dendritic cells maturation, augments the infiltration of antitumor T cells and significantly impedes the primary tumor growth and proliferation. More strikingly, by synergizing with the programmed cell death receptor-1 (PD-1) checkpoint inhibitor, the immunosuppressive microenvironment is remodeled and the survival time of model mice is prolonged. In summary, this paradigm utilizes the tumor-specific microenvironment to boost robust and durable systemic antitumor immunity, providing a novel opportunity for precision cancer theranostics.

Biomimetic Dual-Target Theranostic Nanovaccine Enables Magnetic Resonance Imaging and Chemo/Chemodynamic/Immune Therapy of Glioma

Development of theranostic nanomedicines to tackle glioma remains to be challenging. Here, we present an advanced blood-brain barrier (BBB)-crossing nanovaccine based on cancer cell membrane-camouflaged poly(N-vinylcaprolactam) (PVCL) nanogels (NGs) incorporated with MnO2 and doxorubicin (DOX). We show that the disulfide bond-cross-linked redox-responsive PVCL NGs can be functionalized with dermorphin and imiquimod R837 through cell membrane functionalization. The formed functionalized PVCL NGs having a size of 220 nm are stable, can deplete glutathione, and responsively release both Mn2+ and DOX under the simulated tumor microenvironment to exert the chemo/chemodynamic therapy mediated by DOX and Mn2+, respectively. The combined therapy induces tumor immunogenic cell death to maturate dendritic cells (DCs) and activate tumor-killing T cells. Further, the nanovaccine composed of cancer cell membranes as tumor antigens, R837 as an adjuvant with abilities of DC maturation and macrophages M1 repolarization, and MnO2 with Mn2+-mediated stimulator of interferon gene activation of tumor cells can effectively act on both targets of tumor cells and immune cells. With the dermorphin-mediated BBB crossing, cell membrane-mediated homologous tumor targeting, and Mn2+-facilitated magnetic resonance (MR) imaging property, the designed NG-based theranostic nanovaccine enables MR imaging and combination chemo-, chemodynamic-, and imnune therapy of orthotopic glioma with a significantly decreased recurrence rate.

Genetically Edited Cascade Nanozymes for Cancer Immunotherapy

Immune checkpoint blockade (ICB) has brought tremendous clinical progress, but its therapeutic outcome can be limited due to insufficient activation of dendritic cells (DCs) and insufficient infiltration of cytotoxic T lymphocytes (CTLs). Evoking immunogenic cell death (ICD) is one promising strategy to promote DC maturation and elicit T-cell immunity, whereas low levels of ICD induction of solid tumors restrict durable antitumor efficacy. Herein, we report a genetically edited cell membrane-coated cascade nanozyme (gCM@MnAu) for enhanced cancer immunotherapy by inducing ICD and activating the stimulator of the interferon genes (STING) pathway. In the tumor microenvironment (TME), the gCM@MnAu initiates a cascade reaction and generates abundant cytotoxic hydroxyl (•OH), resulting in improved chemodynamic therapy (CDT) and boosted ICD activation. In addition, released Mn2+ during the cascade reaction activates the STING pathway and further promotes the DC maturation. More importantly, activated immunogenicity in the TME significantly improves gCM-mediated PD-1/PD-L1 checkpoint blockade therapy by eliciting systemic antitumor responses. In breast cancer subcutaneous and lung metastasis models, the gCM@MnAu showed synergistically enhanced therapeutic effects and significantly prolonged the survival of mice. This work develops a genetically edited nanozyme-based therapeutic strategy to improve DC-mediated cross-priming of T cells against poorly immunogenic solid tumors.

pH-responsive iron-loaded carbonaceous nanoparticles for chemodynamic therapy based on the Fenton reaction

The Fenton reaction-based chemodynamic therapy is a form of cancer therapy, and its efficacy can be significantly improved by promoting catalytic reactions involving iron ions. A system with high catalytic capacity and low biological toxicity that effectively inhibits tumor progression is required for optimal treatment. In this study, iron-loaded carbonaceous nanoparticles (CNPs@Fe) with Fenton catalytic activity were fabricated and applied for the chemodynamic therapy of cancer. The carbonaceous nanoparticles derived from glucose via a caramelization reaction demonstrated high biocompatibility. Besides, aromatic structures in the carbonaceous nanoparticles helped accelerate electron transfer to enhance the catalytic decomposition of H2O2, resulting in the formation of highly reactive hydroxyl radicals (˙OH). At pH 6.0 (representing weak acidity in the tumor microenvironment), the Fenton catalytic activity of CNPs@Fe in the decomposition of H2O2 was 15.3 times higher than that of Fe2+ and 28.3 times higher than that of Fe3O4via a chromogenic reaction. The reasons for the enhancement were revealed by analyzing the chemical composition of carbonaceous nanoparticles using high-resolution mass spectra. The developed Fenton agent also demonstrated significant therapeutic effectiveness and minimal side effects in in vitro and in vivo anticancer studies. This work proposes a novel approach to promote the generation of reactive oxygen species (ROS) for the chemodynamic therapy of cancer.

CaCO3 nanoplatform for cancer treatment: drug delivery and combination therapy

The use of nanocarriers for drug delivery has opened up exciting new possibilities in cancer treatment. Among them, calcium carbonate (CaCO3) nanocarriers have emerged as a promising platform due to their exceptional biocompatibility, biosafety, cost-effectiveness, wide availability, and pH-responsiveness. These nanocarriers can efficiently encapsulate a variety of small-molecule drugs, proteins, and nucleic acids, as well as co-encapsulate multiple drugs, providing targeted and sustained drug release with minimal side effects. However, the effectiveness of single-drug therapy using CaCO3 nanocarriers is limited by factors such as multidrug resistance, tumor metastasis, and recurrence. Combination therapy, which integrates multiple treatment modalities, offers a promising approach for tackling these challenges by enhancing efficacy, leveraging synergistic effects, optimizing therapy utilization, tailoring treatment approaches, reducing drug resistance, and minimizing side effects. CaCO3 nanocarriers can be employed for combination therapy by integrating drug therapy with photodynamic therapy, photothermal therapy, sonodynamic therapy, immunotherapy, radiation therapy, radiofrequency ablation therapy, and imaging. This review provides an overview of recent advancements in CaCO3 nanocarriers for drug delivery and combination therapy in cancer treatment over the past five years. Furthermore, insightful perspectives on future research directions and development of CaCO3 nanoparticles as nanocarriers in cancer treatment are discussed.

Enhancing photodynamic immunotherapy by reprograming the immunosuppressive tumor microenvironment with hypoxia relief

Tumor hypoxia impairs the generation of reactive oxygen species and the induction of immunogenic cell death (ICD) for photodynamic therapy (PDT), thus impeding its efficacy and the subsequent immunotherapy. In addition, hypoxia plays a critical role in forming immunosuppressive tumor microenvironments (TME) by regulating the infiltration of immunosuppressive tumor-associated macrophages (TAMs) and the expression of programmed death ligand 1 (PD-L1). To simultaneously tackle these issues, a MnO2-containing albumin nanoplatform co-delivering IR780, NLG919, and a paclitaxel (PTX) dimer is designed to boost photodynamic immunotherapy. The MnO2-catalyzed oxygen supply bolsters the efficacy of PDT and PTX-mediated chemotherapy, collectively amplifying the induction of ICD and the expansion of tumor-specific cytotoxic T lymphocytes (CTLs). More importantly, hypoxia releif reshapes the immunosuppressive TME via down-regulating the intratumoral infiltration of M2-type TAMs and the PD-L1 expression of tumor cells to enhance the infiltration and efficacy of CTLs in combination with immune checkpoint blockade (ICB) by NLG919, consequently eradicating primary tumors and almost completely preventing tumor relapse and metastasis. This study sets an example of enhanced immunotherapy for breast cancers through dual ICD induction and simultaneous immunosuppression modulation via both hypoxia relief and ICB, providing a strategy for the treatment of other hypoxic and immunosuppressive cancers.

A NRF2 Regulated and the Immunosuppressive Microenvironment Reversed Nanoplatform for Cholangiocarcinoma Photodynamic-Gas Therapy

Photodynamic therapy (PDT) is a minimally invasive and controllable local cancer treatment for cholangiocarcinoma (CCA). However, the efficacy of PDT is hindered by intratumoral hypoxia and the presence of an antioxidant microenvironment. To address these limitations, combining PDT with gas therapy may be a promising strategy to enhance tumor oxygenation. Moreover, the augmentation of oxidative damage induced by PDT and gas therapy can be achieved by inhibiting NRF2, a core regulatory molecule involved in the antioxidant response. In this study, an integrated nanotherapeutic platform called CMArg@Lip, incorporating PDT and gas therapies using ROS-responsive liposomes encapsulating the photosensitizer Ce6, the NO gas-generating agent L-arginine, and the NRF2 inhibitor ML385, is successfully developed. The utilization of CMArg@Lip effectively deals with challenges posed by tumor hypoxia and antioxidant microenvironment, resulting in elevated levels of oxidative damage and subsequent induction of ferroptosis in CCA. Additionally, these findings suggest that CMArg@Lip exhibits notable immunomodulatory effects, including the promotion of immunogenic cell death and facilitation of dendritic cell maturation. Furthermore, it contributes to the anti-tumor function of cytotoxic T lymphocytes through the downregulation of PD-L1 expression in tumor cells and the activation of the STING signaling pathway in myeloid-derived suppressor cells, thereby reprogramming the immunosuppressive microenvironment via various mechanisms.

A lipid/PLGA nanocomplex to reshape tumor immune microenvironment for colon cancer therapy

Immune checkpoint blockade therapy provides a new strategy for tumor treatment; however, the insufficient infiltration of cytotoxic T cells and immunosuppression in tumor microenvironment lead to unsatisfied effects. Herein, we reported a lipid/PLGA nanocomplex (RDCM) co-loaded with the photosensitizer Ce6 and the indoleamine 2,3-dioxygenase (IDO) inhibitor 1MT to improve immunotherapy of colon cancer. Arginine-glycine-aspartic acid (RGD) as the targeting moiety was conjugated on 1,2-distearoyl-snglycero-3-phosphoethanolamine lipid via polyethylene glycol (PEG), and programmed cell death-ligand 1 (PD-L1) peptide inhibitor DPPA (sequence: CPLGVRGK-GGG-d(NYSKPTDRQYHF)) was immobilized on the terminal group of PEG via matrix metalloproteinase 2 sensitive peptide linker. The Ce6 and 1MT were encapsulated in PLGA nanoparticles. The drug loaded nanoparticles were composited with RGD and DPPA modified lipid and lecithin to form lipid/PLGA nanocomplexes. When the nanocomplexes were delivered to tumor, DPPA was released by the cleavage of a matrix metalloproteinase 2-sensitive peptide linker for PD-L1 binding. RGD facilitated the cellular internalization of nanocomplexes via avβ3 integrin. Strong immunogenic cell death was induced by 1O2 generated from Ce6 irradiation under 660 nm laser. 1MT inhibited the activity of IDO and reduced the inhibition of cytotoxic T cells caused by kynurenine accumulation in the tumor microenvironment. The RDCM facilitated the maturation of dendritic cells, inhibited the activity of IDO, and markedly recruited the proportion of tumor-infiltrating cytotoxic T cells in CT26 tumor-bearing mice, triggering a robust immunological memory effect, thus effectively preventing tumor metastasis. The results indicated that the RDCM with dual IDO and PD-L1 inhibition effects is a promising platform for targeted photoimmunotherapy of colon cancer.

Three-in-One Peptide Prodrug with Targeting, Assembly and Release Properties for Overcoming Bacterium-Induced Drug Resistance and Potentiating Anti-Cancer Immune Response

The presence of bacteria in tumor results in chemotherapeutic drug resistance and weakens the immune response in colorectal cancer. To overcome bacterium-induced chemotherapeutic drug resistance and potentiate antitumor immunity, herein a novel molecule Biotin-Lys(SA-Cip-OH)-Lys(SA-CPT)-Phe-Phe-Nap (Biotin-Cip-CPT-Nap) is rationally designed containing four functional motifs (i.e., a biotin motif for targeting, Phe-Phe(-Nap) motif for self-assembly, ciprofloxacin derivative (Cip-OH) motif for antibacterial effect, and camptothecin (CPT) motif for chemotherapy). Using the designed molecule, a novel strategy of intracellular enzymatic nanofiber formation and synergistic antibacterium-enhanced chemotherapy and immunotherapy is achieved. Under endocytosis mediated by highly expressed biotin receptor in colorectal cancer cell membrane and the catalysis of highly expressed carboxylesterase in the cytoplasm, this novel molecule can be transformed into Biotin-Nap, which self-assembled into nanofibers. Meanwhile, antibiotic Cip-OH and chemotherapeutic drug CPT are released, overcoming bacterium-induced drug resistance and enhancing the therapeutic efficacy of immunotherapy towards colorectal cancer. This work offers a feasible strategy for the design of novel multifunctional prodrugs to improve the efficiency of colorectal cancer treatment.

Self-Adjuvanting Polyguanidine Nanovaccines for Cancer Immunotherapy

Tapping into the innate immune system's power, nanovaccines can induce tumor-specific immune responses, which is a promising strategy in cancer immunotherapy. However, traditional vaccine design, requiring simultaneous loading of antigens and adjuvants, is complex and poses challenges for mass production. Here, we developed a tumor nanovaccine platform that integrates adjuvant functions into the delivery vehicle, using branched polyguanidine (PolyGu) nanovaccines. These nanovaccines were produced by modifying polyethylenimine (PEI) with various guanidine groups, transforming PEI's cytotoxicity into innate immune activation. The PolyGu nanovaccines based on poly(phenyl biguanidine ) (Poly-PBG) effectively stimulated dendritic cells, promoted their maturation via the TLR4 and NLRP3 pathways, and displayed robust in vivo immune activity. They significantly inhibited tumor growth and extended mouse survival. The PolyGu also showed promise for constructing more potent mRNA-based nanovaccines, offering a platform for personalized cancer vaccine. This work advances cancer immunotherapy toward potential clinical application by introducing a paradigm for developing self-adjuvanting nanovaccines.

Manganese Dioxide Nanoplatform with a Hollow Rhombic Dodecahedron Morphology for Drug Delivery

Manganese dioxide (MnO2) is considered as a promising drug carrier material suitable for the tumor microenvironment while lacking conducive structures for drug loading. Herein, we construct a MnO2 nanoplatform with a hollow rhombic dodecahedral morphology for drug delivery. In this work, we obtained zeolitic imidazolate framework nanoparticles (ZIF-90 NPs) via a coordination reaction. Furthermore, the drug-loading nanoparticles (ZIF-90/DOX NPs) were obtained by Schiff's base reaction and then selected as a sacrificial template to obtain the hollow nanoplatforms (ZIF-90@MnO2 NPs). Moreover, the photothermal effect and multiresponsive drug release behaviors were revealed by loading the photothermal agent IR-820 and the anticancer drug doxorubicin hydrochloride (DOX). Our study demonstrates that the ZIF-90@MnO2 NPs loaded with photosensitizers exhibited excellent photothermal conversion performance. Benefiting from the hollow structure and redox activity, remarkable drug loading and release performances of ZIF-90@MnO2 NPs were achieved. It is shown that ZIF-90@MnO2 NPs achieved a satisfactory drug-loading efficiency (up to ca. 69.7%) for DOX. More promisingly, the ZIF-90@MnO2 NPs exhibited significant glutathione (GSH)/pH-responsive drug release and degradation performances. Overall, this work highlights the potential of controlled drug release of nanocarriers and offers unique insights into the design of nanocarriers with hollow structures.

Copper-coordinated nanoassemblies based on photosensitizer-chemo prodrugs and checkpoint inhibitors for enhanced apoptosis-cuproptosis and immunotherapy

Cuproptosis is a recently identified copper-dependent form of nonapoptotic cell death and holds great prospect in cancer treatment. One of the most intriguing aspects of cuproptosis is its ability to synergize with apoptosis-based cancer treatments. Herein, we presented a novel approach using copper-coordinated nanoassemblies (CCNAs) that were constructed by incorporating a photosensitizer Zinc Phthalocyanine (ZnPc)-chemotherapeutic (DOX) prodrug with a thioketal (TK) spacer and an IDO inhibitor (1-methyl tryptophan, 1-MT) as building blocks for Cu2+-coordination self-assembly to achieve combinational apoptosis-cuproptosis and immunotherapy. Upon NIR laser irradiation, the ZnPc component of CCNAs exhibited a photodynamic effect that generated reactive oxygen species (ROS). This triggered the release of DOX, leading to enhanced tumor cell apoptosis. Additionally, the presence of Cu2+ in the CCNAs not only enhanced the photodynamic process by catalyzing oxygen generation but also promoted the aggregation of toxic mitochondrial proteins, leading to cell cuproptosis. Importantly, the intensified cuproptosis-apoptosis effect triggered an immunogenic cell death (ICD) response. The released 1-MT complemented this response by reversing the immunosuppressive tumor microenvironment (ITM), synergistically amplifying anti-tumor immunity and suppressing the growth of primary and distant tumors. The findings of this study provide a new perspective on potential cancer treatments based on cuproptosis-apoptosis synergistic immunotherapy and stimulate further research in the design of advanced metal-coordinated nanomedicines. STATEMENT OF SIGNIFICANCE: The combination of cuproptosis and apoptosis that act with different mechanisms holds enormous potential in cancer treatment. Here, copper-coordinated nanoassemblies (CCNAs) based on photosensitizer-chemo prodrugs and checkpoint inhibitors were constructed for mediating cuproptosis-apoptosis and subsequently promoting cancer immunotherapy. CCNAs not only promoted the photodynamic effect and activation of chemotherapy through catalyzing the generation of oxygen but also induced toxic mitochondrial protein aggregation, leading to cell cuproptosis. These synergistic antitumor effects triggered robust immune responses with the aid of immune checkpoint blockade, almost eradicating primary tumors and inhibiting distant tumors by around 83 % without systemic toxicity.

Hydrogel-mediated tumor T cell infiltration and immune evasion to reinforce cancer immunotherapy

Cancer immunotherapy has received increasing attention in tumor therapy. However, insufficient infiltration of T cells and over-expressed PD-L1 checkpoint in tumor cells severely impede cancer immunotherapy. Here, an injectable hydrogel was designed to reinforce T cell infiltration and inactivate PD-L1 for powerful cancer immunotherapy. The hydrogel was created by sodium alginate (SA) as the gelator, where linagliptin particles and BMS-202 particles were present in hydrogel micropores. After gelation in the tumor site, the linagliptin powerfully suppressed chemokine CXCL10 degradation, enabling the introduced CXCL10 to realize sustainable chemotaxis towards strong T cell infiltration. Meanwhile, the BMS-202 inactivated PD-L1 of tumor cells, thereby eliminating the PD-L1-governed immune evasion. Therefore, the hydrogel in combination with CXCL10 demonstrated powerful cancer immunotherapy against primary and distant tumors, along with efficient inhibition of lung metastasis. Our study not only offers a potent platform against tumors, but also provides a conceptually new approach to reinforce cancer immunotherapy.

Endoplasmic Reticulum-Targeting AIE Photosensitizers to Boost Immunogenic Cell Death for Immunotherapy of Bladder Carcinoma

Bladder cancer is characterized by high rates of recurrence and multifocality. Immunogenic cell death (ICD) of cancer cells has emerged as a promising strategy to improve the immunogenicity of tumor cells for enhanced cancer immunotherapy. Although photosensitizer-based photodynamic therapy (PDT) has been validated as capable of inducing ICD in cancer cells, the photosensitizers with a sufficient ICD induction ability are still rare, and there have been few reports on the development of advanced photosensitizers to strongly evoke the ICD of bladder cancer cells for eliciting potent antitumor immune responses and eradicating bladder carcinoma in situ. In this work, we have synthesized a new kind of endoplasmic reticulum (ER)-targeting aggregation-induced emission (AIE) photosensitizer (named DPASCP-Tos), which could effectively anchor to the cellular ER and trigger focused reactive oxygen species (ROS) production within the ER, thereby boosting ICD in bladder cancer cells. Furthermore, we have demonstrated that bladder cancer cells killed by ER-targeted PDT could serve as a therapeutic cancer vaccine to elicit a strong antitumor immunity. Prophylactic vaccination of the bladder cancer cells killed by DPASCP-Tos under light irradiation promoted the maturation of dendritic cells (DCs) and the expansion of tumor antigen-specific CD8+ T cells in vivo and protected mice from subsequent in situ bladder tumor rechallenge and extended animal survival. In summary, the ER-targeted AIEgens developed here significantly amplified the ICD of bladder cells through focused ROS-based ER oxidative stress and transformed bladder cancer cells into the therapeutic vaccine to enhance immunogenicity against orthotopic bladder cancer, providing valuable insights for bladder carcinoma treatment.

In Situ Nanofiber Patch Boosts Postoperative Hepatocellular Carcinoma Immune Activation by Trimodal Combination Therapy

Poor clinical efficacy associated with postoperative hepatocellular carcinoma (HCC) often results from recurrence and metastasis. Hence, research has focused on establishing an effective multimodal therapy. However, complex combinations of active ingredients require multiple functions in therapeutic systems. Herein, a portable nanofiber patch composing germanium phosphorus (GeP) and anlotinib (AL) was designed to form a versatile platform for molecularly targeted photothermal-immune checkpoint blockade (ICB) trimodal combination therapy. The patches possess hydrophilic, satisfactory mechanical, and excellent photothermal conversion properties. Moreover, they achieve a penetrating and sustained drug release. The near-infrared light-assisted GeP-induced temperature increase regulates AL release, downregulating the expression of vascular-related factor receptors, triggering immunogenic cell death of tumor cells, and inducing dendritic cell maturation. Simultaneously, ICB therapy (programmed cell death ligand 1, PD-L1) was introduced to improve treatment outcomes. Notably, this trimodal combination therapy significantly inhibits vascular hypergrowth, enhances effector T-cell infiltration, and sensitizes the PD-L1 antibody response, boosting immunotherapy to suppress residual HCC recurrence and metastasis. Further validation of the genome sequencing results revealed cell pathways related primarily to regulatory immune effects. This study demonstrates the use of an effective and practical nanofiber patch to improve multimodal therapy of postoperative HCC, with high clinical translation value.

A pro-death autophagy-based nanoplatform for enhancing antitumour efficacy with improved immune responses

Due to the pro-survival effect of mild autophagy, the therapeutic effect of chemo-immunotherapy is unsatisfactory. In addition, the adverse tumour microenvironment (TME), including the lack of antigen presentation, the deficiency of oxygen supply and immunosuppressive cells, results in immune escape and metastasis. Herein, a novel nanoplatform (CS-3BP/PA@DOX) based on the autophagy cascade is proposed for the first time to deliver the chemotherapeutic doxorubicin (DOX) and respiration inhibitor 3-bromopyruvic acid (3BP) to overcome the above obstacles. CS-3BP/PA@DOX exerts a synergistic therapeutic effect to initiate pro-death autophagy and facilitate the antigen presentation process by combining DOX chemotherapy and starvation therapy with 3BP. Additionally, CS-3BP/PA@DOX remodelled the immunosuppressive TME by alleviating hypoxia, damaging dense ECM, and downregulating PD-L1 to enhance antitumour immunity. 3BP was found to promote GSH depletion by inhibiting respiration for the first time, which reduces the chemical resistance of cancer and increases the sensitivity of cells to ROS, providing a new therapeutic direction of 3BP for antitumour treatment. Collectively, this study offers an opportunity to magnify pro-death autophagy, augment antitumour efficacy, facilitate anti-metastatic effects, and boost immune responses.

Mn(iii)-mediated carbon-centered radicals generate an enhanced immunotherapeutic effect

A strategy for designing cancer therapeutic nanovaccines based on immunogenic cell death (ICD)-inducing therapeutic modalities is particularly attractive for optimal therapeutic efficacy. In this work, a highly effective cancer therapeutic nanovaccine (denoted as MPL@ICC) based on immunogenic photodynamic therapy (PDT) was rationally designed and fabricated. MPL@ICC was composed of a nanovehicle of MnO2 modified with a host-guest complex using amino pillar[6]arene and lactose-pyridine, a prodrug of isoniazid (INH), and chlorine e6 (Ce6). The nanovaccine exhibited excellent biosafety, good targeting ability to hepatoma cells and enrichment at tumor sites. Most importantly, it could modulate the tumor microenvironment (TME) to facilitate the existence of Mn(iii) and Mn(iii)-mediated carbon-centered radical generation with INH released from the prodrug in situ to further strengthen ICD. This is the first report on Mn(iii)-mediated generation of carbon-centered radicals for successful anti-tumor immunotherapy using ICD, which provides a novel strategy for designing highly efficient cancer therapeutic nanovaccines.

Nanoplatform-enhanced photodynamic therapy for the induction of immunogenic cell death

As an efficient, non-invasive, low-side-effect, and highly selective cancer therapy, photodynamic therapy (PDT) is used to treat various malignant tumors. However, the inefficiency of dealing with deep tumors and metastatic lesions highly limits the use of PDT. Immunogenic cell death (ICD) is a particular form of tumor cell death that could elicit a tumor-special immune response, leading to a systemic anti-tumor effect and providing therapeutic benefits for metastatic lesions. In this regard, it is crucial to enhance the ability of PDT to induce ICD. Luckily, advanced nanotechnology created many promising ways to improve the immunogenicity of PDT and achieve photoimmunotherapy. This review summarizes the emerging strategies for triggering immunogenic cell death via nanoplatform-enhanced PDT, with particular emphasis on their advantages in photoimmunotherapy. We highlight the nanoplatforms classified according to the basic principles of photodynamic therapy and immunogenic cell death, which provides a valuable reference for the design of nanoplatform for photoimmunotherapy. In addition, we also discuss the current situation and prospect of nano-based photoimmunotherapy in clinical studies.

Microbes mediated immunogenic cell death in cancer immunotherapy

Immunogenic cell death (ICD) is one of the 12 distinct cell death forms, which can trigger immune system to fight against cancer cells. During ICD, a number of cellular changes occur that can stimulate an immune response, including the release of molecules called damage-associated molecular patterns (DAMPs), signaling to immune cells to recognize and attack cancer cells. By virtue of their pivotal role in immune surveillance, ICD-based drug development has been a new approach to explore novel therapeutic combinations and personalized strategies in cancer therapy. Several small molecules and microbes can induce ICD-relevant signals and cause cancer cell death. In this review, we highlighted the role of microbe-mediate ICD in cancer immunotherapy and described the mechanisms through which microbes might serve as ICD inducers in cancer treatment. We also discussed current attempts to combine microbes with chemotherapy regimens or immune checkpoint inhibitors (ICIs) in the treatment of cancer patients. We surmise that manipulation of microbes may guide personalized therapeutic interventions to facilitate anticancer immune response.

A Bacterial Nanomedicine Combines Photodynamic-Immunotherapy and Chemotherapy for Enhanced Treatment of Oral Squamous Cell Carcinoma

Bacterial therapy is an emerging hotspot in tumor immunotherapy, which can initiate antitumor immune activation through multiple mechanisms. Porphyromonas gingivalis (Pg), a pathogenic bacterium inhabiting the oral cavity, contains a great deal of pathogen associated molecular patterns that can activate various innate immune cells to promote antitumor immunity. Owing to the presence of protoporphyrin IX (PpIX), Pg is also an excellent photosensitizer for photodynamic therapy (PDT) via the in situ generation of reactive oxygen species. This study reports a bacterial nanomedicine (nmPg) fabricated from Pg through lysozyme degradation, ammonium chloride lysis, and nanoextrusion, which has potent PDT and immune activation performances for oral squamous cell carcinoma (OSCC) treatment. To further promote the tumoricidal efficacy, a commonly used chemotherapeutic drug doxorubicin (DOX) is efficiently encapsulated into nmPg through a simple incubation method. nmPg/DOX thus prepared exhibits significant synergistic effects on inhibiting the growth and metastasis of OSCC both in vitro and in vivo via photodynamic-immunotherapy and chemotherapy. In summary, this work develops a promising bacterial nanomedicine for enhanced treatment of OSCC.

Engineering Diselenide-IR780 Homodimeric Nanoassemblies with Enhanced Photodynamic and Immunotherapeutic Effects for Triple-Negative Breast Cancer Treatment

Photodynamic therapy (PDT) has emerged as an efficient approach for non-invasive cancer treatment. However, organic small-molecule photosensitizers are often associated with defects in hydrophobicity, poor photostability, and aggregation-caused quenching, which limit their application. Usually, the carrier-assisted drug delivery system is a common strategy to solve the above obstacles, but additional carrier material could increase the risk of potential biological toxicity. The carrier-free drug delivery system with easy preparation and high drug-loading capability is proposed subsequently as a potential strategy to develop the clinical use of hydrophobic drugs. Herein, we rationally designed three IR780-based carrier-free nanosystems formed by carbon/disulfide/diselenide bond conjugated IR780-based homodimers. The IR780-based homodimers could self-assemble to form nanoparticles (DC-NP, DS-NP, DSe-NP) and exhibited higher reactive oxygen species generation capability and photostability than free IR780, in which DSe-NP with 808 nm laser irradiation performed best and resulted in the strongest cytotoxicity to 4T1 cells. Meanwhile, the glutathione consumption ability of DSe-NP boosted its PDT effect and then induced excessive oxidative stress of 4T1 cells, increasing antitumor efficacy by enhancing immunogenic cell death further. In tumor-bearing mice, DSe-NP displayed obvious tumor site accumulation, which obviously inhibited tumor growth and metastasis, and enhanced the immunological effect by effectively inducing dendritic cells to mature and activating T lymphocytes and natural killer cells. In summary, our study presented an IR780-based carrier-free nanodelivery system for a combination of PDT and immunity therapy and established expanding the application of organic small-molecule photosensitizers by an approach of carrier-free drug delivery system.

Metal-organic framework-based photodynamic combined immunotherapy against the distant development of triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) is an aggressive, metastatic and apparently drug-resistant subtype of breast cancer with a higher immune response compared to other types of breast cancer. Photodynamic therapy (PDT) has been gaining popularity for its non-invasive nature, minimal side effects, and spatiotemporally controlled benifits. The use of metal-organic frameworks (MOFs) loaded with programmed death-ligand 1 inhibitors (iPD-L1) offers the possibility of combining PDT with immunotherapy.

METHOD

Here, we construct PCN-224, a MOFs with good biocompatibility and biodegradability for the delivery of the PD-L1 small molecule inhibitor BMS-202 to achieve a synergistic anti-tumor strategy of PDT and immunotherapy. Hyaluronic acid (HA) modified PEG (HA-PEG) was synthesized for the outer layer modification of the nanocomplex, which prolongs its systemic circulation time.

RESULTS

In vitro cellular experiments show that the nanocomplexes irradiated by 660 nm laser has a strong ability to produce singlet oxygen, which effectively induce PDT. PDT with strong immunogenicity leads to tumor necrosis and apoptosis, and induces immunogenic cell death, which causes tumor cells to release danger associated molecular patterns. In combination with iPD-L1, the combination therapy stimulates dendritic cell maturation, promotes T-cell activation and intratumoral infiltration, and reshapes the tumor immune microenvironment to achieve tumor growth inhibition and anti-distant tumor progression.

CONCLUSIONS

MOFs-based nano-systems as a platform for combination therapy offer a potentially effective strategy for the treatment of TNBC with high metastatic rates.

"Closed-Loop" O2-Economizer Induced In Situ Therapeutic Vaccine against Hypoxic Tumors

Therapeutic tumor vaccines, which use tumor antigens to stimulate a cancer patient's immune system to eventually kill the tumor tissues, have emerged as one of the most attractive strategies in anticancer research. Especially, exploring in situ vaccines has become a potential field in cancer immunotherapy. However, due to the hypoxic tumor microenvironment, the generation of tumor antigens is always mild and not sufficient. Hence, in this study, we designed a closed-loop mitochondrial oxygen-economizer (TPCA) to induce enhanced phototherapy-driven in situ vaccines. The O2-economizer was developed by the integration of the photosensitizer CyI and the mitochondrial inhibitor atovaquone into the PAMAM dendrimer. In vitro and in vivo studies showed that TPCA could enter the mitochondria through (3-propylcarboxyl) triphenylphosphine bromide (TPP) and effectively restrict the respiration of tumor cells to reduce tumor hypoxia, thus providing continuous oxygen for enhanced iodinated cyanine dye mediated photodynamic therapy, which could further induce in situ vaccines for ablating the primary tumor directly and inhibiting the tumor metastasis and recurrence. Furthermore, the antitumor mechanism revealed that O2-economizer-based oxygen-boosted PDT elicited immunogenic cancer cell death with enhanced exposure and release of DAMPs and altered the immunosuppressive tumor microenvironment with increased recruitment of T cells in tumors, thereby inducing in situ vaccines and provoking the systematic antitumor responses against CT26 tumors. This study will provide innovative approaches for local, abscopal, and metastatic tumor treatment.

Nickel(II) Phototheranostics: A Case Study in Photoactivated H2O2-Enhanced Immunotherapy

Phototheranostics have emerged as a promising subset of cancer theranostics owing to their potential to provide precise photoinduced diagnoses and therapeutic outcomes. However, the design of phototheranostics remains challenging due to the nature of tumors and their microenvironment, including limitations to the oxygen supply, high rates of recurrence and metastasis, and the immunosuppressive state of cancer cells. Here we report a dual-functional oxygen-independent phototheranostic agent, Ni-2, rationally designed to provide a near-infrared (NIR) photoactivated thermal- and hydroxyl radical (•OH)-enhanced photoimmunotherapeutic anticancer response. Under 880 nm laser irradiation, Ni-2 exhibited high photostability and excellent photoacoustic and photothermal effects with a photothermal conversion efficacy of 58.0%, as well as novel photoredox features that allowed the catalytic conversion of H2O2 to •OH upon photooxidation of Ni(II) to Ni(III). As a multifunctional photoagent, Ni-2 was found not only to inhibit tumor growth in a CT26 tumor-bearing mouse model but also to activate an immune response via a combination of photothermal- and H2O2-induced effects. When combined with an antiprogrammed death-ligand 1 (aPD-L1), Ni-2 treatment allowed for the suppression of distant tumor growth and cancer metastasis. Collectively, the present results provide support for the proposition that Ni-2 or its analogues could emerge as useful tools for photoimmunotherapy. They also highlight the potential of appropriately designed 3d transition metal complexes as "all- in-one" phototheranostics.

Controllable hypoxia-activated chemotherapy as a dual enhancer for synergistic cancer photodynamic immunotherapy

The efficacy of photodynamic therapy (PDT) is severely limited by the hypoxic tumor microenvironment (TME), while the performance of PDT-aroused antitumor immunity is frustrated by the immunosuppressive TME and deficient immunogenic cell death (ICD) induction. To simultaneously tackle these pivotal problems, we herein create an albumin-based nanoplatform co-delivering IR780, NLG919 dimer and a hypoxia-activated prodrug tirapazamine (TPZ) as the dual enhancer for synergistic cancer therapy. Under NIR irradiation, IR780 generates 1O2 for PDT, which simultaneously cleaves the ROS-sensitive linker for triggered TPZ release, and activates its chemotherapy via exacerbated tumor hypoxia. Meanwhile, firstly found by us, TPZ-mediated chemotherapy boosts PDT-induced tumor ICD to evoke stronger antitumor immunity including the development of tumor-specific cytotoxic T lymphocytes (CTLs). Eventually, enriched intratumoral GSH triggers the activation of NLG919 to mitigate the immunosuppressive TME via specific indoleamine 2,3-dioxygenase 1 (IDO-1) inhibition, consequently promoting the intratumoral infiltration of CTLs and the killing of both primary and distant tumors, while the resultant memory T cells allows nearly 100% suppression of tumor recurrence and metastasis. This nanoplatform sets up an example for dully enhanced photodynamic immunotherapy of breast cancer via hypoxia-activated chemotherapy, and paves a solid way for the treatment of other hypoxic and immunosuppressive malignant tumors.

Stimulators of immunogenic cell death for cancer therapy: focusing on natural compounds

A growing body of evidence indicates that the anticancer effect of the immune system can be activated by the immunogenic modulation of dying cancer cells. Cancer cell death, as a result of the activation of an immunomodulatory response, is called immunogenic cell death (ICD). This regulated cell death occurs because of increased immunogenicity of cancer cells undergoing ICD. ICD plays a crucial role in stimulating immune system activity in cancer therapy. ICD can therefore be an innovative route to improve anticancer immune responses associated with releasing damage-associated molecular patterns (DAMPs). Several conventional and chemotherapeutics, as well as preclinically investigated compounds from natural sources, possess immunostimulatory properties by ICD induction. Natural compounds have gained much interest in cancer therapy owing to their low toxicity, low cost, and inhibiting cancer cells by interfering with different mechanisms, which are critical in cancer progression. Therefore, identifying natural compounds with ICD-inducing potency presents agents with promising potential in cancer immunotherapy. Naturally derived compounds are believed to act as immunoadjuvants because they elicit cancer stress responses and DAMPs. Acute exposure to DAMP molecules can activate antigen-presenting cells (APCs), such as dendritic cells (DCs), which leads to downstream events by cytotoxic T lymphocytes (CTLs) and natural killer cells (NKs). Natural compounds as inducers of ICD may be an interesting approach to ICD induction; however, parameters that determine whether a compound can be used as an ICD inducer should be elucidated. Here, we aimed to discuss the impact of multiple ICD inducers, mainly focusing on natural agents, including plant-derived, marine molecules, and bacterial-based compounds, on the release of DAMP molecules and the activation of the corresponding signaling cascades triggering immune responses. In addition, the potential of synthetic agents for triggering ICD is also discussed.

Reinforcing the immunogenic cell death to enhance cancer immunotherapy efficacy

Immunogenic cell death (ICD) has been a revolutionary modality in cancer treatment since it kills primary tumors and prevents recurrent malignancy simultaneously. ICD represents a particular form of cancer cell death accompanied by production of damage-associated molecular patterns (DAMPs) that can be recognized by pattern recognition receptors (PRRs), which enhances infiltration of effector T cells and potentiates antitumor immune responses. Various treatment methods can elicit ICD involving chemo- and radio-therapy, phototherapy and nanotechnology to efficiently convert dead cancer cells into vaccines and trigger the antigen-specific immune responses. Nevertheless, the efficacy of ICD-induced therapies is restrained due to low accumulation in the tumor sites and damage of normal tissues. Thus, researchers have been devoted to overcoming these problems with novel materials and strategies. In this review, current knowledge on different ICD modalities, various ICD inducers, development and application of novel ICD-inducing strategies are summarized. Moreover, the prospects and challenges are briefly outlined to provide reference for future design of novel immunotherapy based on ICD effect.

Biomimetic biomineralization nanoplatform-mediated differentiation therapy and phototherapy for cancer stem cell inhibition and antitumor immunity activation

Growing evidence suggests that the presence of cancer stem cells (CSCs) is a major challenge in current tumor treatments, especially the transition from non-CSCs to differentiation of CSCs for evading conventional therapies and driving metastasis. Here we propose a therapeutic strategy of synergistic differentiation therapy and phototherapy to induce differentiation of CSCs into mature tumor cells by differentiation inducers and synergistic elimination of them and normal cancer cells through phototherapy. In this work, we synthesized a biomimetic nanoplatform loaded with IR-780 and all-trans retinoic acid (ATRA) via biomineralization. This method can integrate aluminum ions into small-sized protein carriers to form nanoclusters, which undergo responsive degradation under acidic conditions and facilitate deep tumor penetration. With the help of CSC differentiation induced by ATRA, IR-780 inhibited the self-renewal of CSCs and cancer progression by generating hyperthermia and reactive oxygen species in a synergistic manner. Furthermore, ATRA can boost immunogenic cell death induced by phototherapy, thereby strongly causing a systemic anti-tumor immune response and efficiently eliminating CSCs and tumor cells. Taken together, this dual strategy represents a new paradigm of targeted eradication of CSCs and tumors by inducing CSC differentiation, improving photothermal therapy/photodynamic therapy and enhancing antitumor immunity.

Remodeling the tumor immune microenvironment via siRNA therapy for precision cancer treatment

How to effectively transform the pro-oncogenic tumor microenvironments (TME) surrounding a tumor into an anti-tumoral never fails to attract people to study. Small interfering RNA (siRNA) is considered one of the most noteworthy research directions that can regulate gene expression following a process known as RNA interference (RNAi). The research about siRNA delivery targeting tumor cells and TME has been on the rise in recent years. Using siRNA drugs to silence critical proteins in TME was one of the most efficient solutions. However, the manufacture of a siRNA delivery system faces three major obstacles, i.e., appropriate cargo protection, accurately targeted delivery, and site-specific cargo release. In the following review, we summarized the pharmacological actions of siRNA drugs in remolding TME. In addition, the delivery strategies of siRNA drugs and combination therapy with siRNA drugs to remodel TME are thoroughly discussed. In the meanwhile, the most recent advancements in the development of all clinically investigated and commercialized siRNA delivery technologies are also presented. Ultimately, we propose that nanoparticle drug delivery siRNA may be the future research focus of oncogene therapy. This summary offers a thorough analysis and roadmap for general readers working in the field.

Metal-Based Photosensitizers as Inducers of Regulated Cell Death Mechanisms

Over the last few decades, various forms of regulated cell death (RCD) have been discovered and were found to improve cancer treatment. Although there are several reviews on RCD induced by photodynamic therapy (PDT), a comprehensive summary covering metal-based photosensitizers (PSs) as RCD inducers has not yet been presented. In this review, we systematically summarize the works on metal-based PSs that induce different types of RCD, including ferroptosis, immunogenic cell death (ICD), and pyroptosis. The characteristics and mechanisms of each RCD are explained. At the end of each section, a summary of the reported commonalities between different metal-based PSs inducing the same RCD is emphasized, and future perspectives on metal-based PSs inducing novel forms of RCD are discussed at the end of the review. Considering the essential roles of metal-based PSs and RCD in cancer therapy, we hope that this review will provide the stage for future advances in metal-based PSs as RCD inducers.

Cell membrane-specific self-assembly of peptide nanomedicine induces tumor immunogenic death to enhance cancer therapy

Immunogenic cell death (ICD), as an unusual cell death pattern, mediates cancer cells to release a series of damage-associated molecular patterns (DAMPs), and is widely used in the field of cancer immunotherapy. Injuring the cell membrane can serve as a novel ICD initiation strategy. In this study, a peptide nanomedicine (PNpC) is designed using the fragment CM11 of cecropin, which is effective in disrupting cell membranes because of its α-helical structure. PNpC self-assembles in situ in the presence of high levels of alkaline phosphatase (ALP) on the tumor cell membrane, transforming from nanoparticles to nanofibers, which reduces the cellular internalization of the nanomedicine and increases the interaction between CM11 and tumor cell membranes. Both in vitro and in vivo results indicate that PNpC plays a significant role in killing tumor cells by triggering ICD. The ICD induced by the destruction of the cancer cell membrane is accompanied by the release of DAMPs, which promotes the maturation of DCs and facilitates the presentation of tumor-associated antigens (TAA), resulting in the infiltration of CD8+ T cells. We believe that PNpC can trigger ICD while killing cancer cells, providing a new reference for cancer immunotherapy.

PD-L1 Blockade Peptide-Modified Polymeric Nanoparticles for Oxygen-Independent-Based Hypoxic Tumor Photo/Thermodynamic Immunotherapy

Distant metastasis of malignant tumors is considered to be the main culprit for the failure of current antitumor treatments. Conventional single treatments often exhibit limited efficacy in inhibiting tumor metastasis. Therefore, there is a growing interest in developing collaborative antitumor strategies based on photothermal therapy (PTT) and free-radical-generated photodynamic therapy (PDT), especially utilizing oxygen-independent nanoplatforms, to address this challenge. Such antitumor strategies can enhance the therapeutic outcomes by ensuring the cytotoxicity of free radicals even in the hypoxic tumor microenvironment, thereby improving the effective suppression of primary tumors. Additionally, these approaches can stimulate the production of tumor-associated antigens and amplify the immunogenic cell death (ICD) effects, potentially feasible for enhancing the therapeutic outcomes of immunotherapy. Herein, we fabricated a functional nanosystem that co-loads IR780 and 2,2'-azobis[2-(2-imidazolin-2-yl)propane]-dihydrochloride (AIPH) to realize PTT-triggered thermodynamic combination therapy via the oxygen-independent pathway for the elimination of primary tumors. Furthermore, the nanocomposites were surface-decorated with a predesigned complex peptide (PLGVRGC-anti-PD-L1 peptide, MMP-sensitive), which facilitated the immunotherapy targeting distant tumors. Through the specific recognition of matrix metalloproteinase (MMP), the sensitive segment on the obtained aNC@IR780A was cleaved. As a result, the freed anti-PD-L1 peptide effectively blocked immune checkpoints, leading to the infiltration and activation of T cells (CTLs). This nanosystem was proven to be effective at inhibiting both primary tumors and distant tumors, providing a promising combination strategy for tumor PTT/TDT/immunotherapy.

Lipid nanoparticle-based mRNA delivery systems for cancer immunotherapy

Cancer immunotherapy, which harnesses the power of the immune system, has shown immense promise in the fight against malignancies. Messenger RNA (mRNA) stands as a versatile instrument in this context, with its capacity to encode tumor-associated antigens (TAAs), immune cell receptors, cytokines, and antibodies. Nevertheless, the inherent structural instability of mRNA requires the development of effective delivery systems. Lipid nanoparticles (LNPs) have emerged as significant candidates for mRNA delivery in cancer immunotherapy, providing both protection to the mRNA and enhanced intracellular delivery efficiency. In this review, we offer a comprehensive summary of the recent advancements in LNP-based mRNA delivery systems, with a focus on strategies for optimizing the design and delivery of mRNA-encoded therapeutics in cancer treatment. Furthermore, we delve into the challenges encountered in this field and contemplate future perspectives, aiming to improve the safety and efficacy of LNP-based mRNA cancer immunotherapies.