Semiconducting polymer nano-PROTACs for activatable photo-immunometabolic cancer therapy

Innovative sarcoma therapy using multifaceted nano-PROTAC-induced EZH2 degradation and immunity enhancement

Sarcomas are highly malignant tumors characterized by their heterogeneity and resistance to conventional therapies, which significantly limit treatment options. EZH2 is highly expressed in sarcomas, but targeting it is difficult. In this study, we uncovered the non-canonical transcriptional mechanisms of EZH2 in sarcoma and highlighted the essential role of EZH2 in regulating YAP1 through non-canonical transcriptional pathways in the progression of sarcoma. Building on this, we developed YM@VBM, a novel and versatile nano-PROTAC (proteolysis-targeting chimera), by integrating a polyphenol-vanadium oxide system with the EZH2 degrader YM281 PROTAC, encapsulated in methoxy polyethylene glycol-NH2 to enhance biocompatibility. To further facilitate targeted drug delivery to tumors, YM@VBM nano-PROTACs were incorporated into microneedle patches. Our engineered YM@VBM exhibited multiple functionalities, including the peroxidase-like activity to generate reactive oxygen species, depletion of glutathione, and photothermal effects, specifically targeting sarcoma characteristics. YM@VBM significantly enhanced targeting efficacy via inducing potent EZH2 degradation. Most importantly, it can also activate anti-tumor immunity via excluding myeloid-derived suppressor cells, maturing dendritic cells, and forming tertiary lymphoid structures. Hence, we reveal that YM@VBM presents a promising treatment strategy for sarcoma, offering a multifaceted approach to combat this challenging malignancy.

Advancements in delivery Systems for Proteolysis-Targeting Chimeras (PROTACs): Overcoming challenges and expanding biomedical applications

PROTAC (Proteolysis-Targeting Chimera), an emerging drug development strategy based on small molecule technology, has garnered widespread attention due to its high efficiency, broad applicability, low resistance, and dosage advantages. However, PROTAC molecules still exhibit certain limitations that require urgent resolution. Although significant progress has been made in designing PROTACs that target various disease-related proteins, research on drug delivery systems (DDS) for PROTACs remains relatively limited. This review aims to explore the critical role of delivery system design in addressing the inherent challenges associated with PROTAC molecules from a novel perspective. Beginning with five major challenges-insufficient targeting, poor pharmacokinetic properties, low cell permeability, limited accessibility, and the Hook effect-this article introduces formulation strategies to mitigate these deficiencies. It discusses potential solutions through targeted modifications, nano-delivery systems, intelligent response systems, and membrane biomimetic technologies, among others. Furthermore, it elucidates the mechanisms and principles underlying these approaches and analyzes the advantages of various delivery strategies. The insights provided in this review offer insights for designing delivery systems tailored to PROTACs with diverse characteristics for different disease applications.

Homologous-Targeting Porous Type I/II Nanophotosensitizers for Efficient Delivery of STING Agonists and Enhanced Photodynamic Cancer Immunotherapy

Immunotherapy as a transformative cancer treatment modality frequently struggles with the immunosuppressive tumor microenvironment, which hinders effective immune responses. In this report, we construct biomimetic tumor cell membrane-cloaked porous covalent organic framework (COF) nanophotosensitizers (CMSCOFs) to synergistically enhance photodynamic therapy (PDT) and stimulate interferon genes (STING)-mediated immunotherapy. CMSCOF is prepared from porphyrin and benzothiadiazole-based units and cloaked with 4T1 cancer cell membranes for homologous tumor targeting. The porous structure of COF enables efficient encapsulation of the non-nucleotide STING agonist SR717. Upon 660 nm light irradiation, CMSCOFs trigger both type I and II photodynamic effects by producing both superoxide (O2•-) and singlet oxygen (1O2). The tumor cell membrane-cloaked design improves the stability of the nanophotosensitizers and mimics the natural cancer cells for enhanced blood circulation, tumor accumulation, and homologous-targeting to tumors. Inside tumor tissues, this unique CMSCOF design leads to enhanced immunogenic cell death (ICD) of tumor cells upon exposure to light irradiation. Furthermore, the encapsulated STING agonist SR717 is released after cellular internalization to activate the STING pathway and elicit a potent antitumor immune response. This synergistic approach effectively reverses the immunosuppressive tumor microenvironment, enhances cytotoxic T cell infiltration, and suppresses both primary and metastatic tumors, demonstrating the potential of CMSCOF nanophotosensitizers as a promising platform for photodynamic cancer immunotherapy.

Biomimetic Hybrid PROTAC Nanovesicles Block Multiple DNA Repair Pathways to Overcome Temozolomide Resistance Against Orthotopic Glioblastoma

Glioblastoma (GBM) remains one of the deadliest forms of cancer due to its high rates of postoperative recurrence and resistance to treatment. Temozolomide (TMZ) is the standard chemotherapy for GBM. However, the therapeutic efficacy of TMZ is significantly compromised by the activation of various intracellular DNA repair mechanisms that facilitate TMZ resistance. Herein, the upregulation of bromodomain-containing protein 4 (BRD4) expression is demonstrated to be a key contributor to TMZ resistance in GBM. To address this challenge, a biomimetic hybrid PROteolysis TArgeting Chimeras (PROTAC) liposome delivery system (M@TP) is developed. This system efficiently penetrates the blood-brain barrier (BBB) and specifically targets GBM cells through homotypic recognition. Once within TMZ-resistant GBM cells, the released PROTAC from M@TP can specifically degrade BRD4, effectively inhibiting multiple DNA repair pathways and restoring sensitivity to TMZ treatment. In vivo, studies showed that M@TP demonstrated significant efficacy in suppressing tumor growth in both TMZ-resistant and postoperative GBM, with prolonged mouse survival times. These findings highlight the potential of M@TP as a promising strategy to overcome TMZ resistance and improve therapeutic outcomes in GBM.

PROTAC 2.0: Expanding the frontiers of targeted protein degradation

Proteolysis targeting chimera (PROTAC) technology has revolutionized targeted protein degradation via the ubiquitin-proteasome system. Despite their efficacy in degrading previously undruggable proteins, classical PROTACs face challenges such as poor permeability, dose-dependent effects, and off-target toxicity, prompting the rise of next-generation PROTACs (PROTAC 2.0). This review explores emerging PROTAC-based strategies aimed at enhancing selectivity, bioavailability, and pharmacokinetics. We discuss innovative approaches such as photoactivable PROTACs, hypoxia-responsive degraders, dual and trivalent PROTACs, and antibody-conjugated degraders. Additionally, nanotechnology-based delivery systems are highlighted as promising tools to overcome membrane permeability issues. By analyzing these novel strategies, we highlight the evolution of PROTACs and their growing therapeutic potential. Advances in PROTAC 2.0 technologies are expected to expand their clinical applications, offering more selective and efficient degradation mechanisms.

Tumor microenvironment responsive nano-PROTAC for BRD4 degradation enhanced cancer photo-immunotherapy

Proteolysis Targeting Chimeras (PROTAC) technology has garnered great attention due to its advantages in targeted protein degradation, promising its potential for treating malignant cancer. Nevertheless, the inherent drawbacks of PROTAC technology hinder its clinical translation. The integration of nanotechnology with PROTAC molecules to create nano-PROTACs for combined therapy offers a promising solution. Among the various cancer treatment methods, phototherapy is considered the optimal choice to integrate with specific PROTACs due to its proven effectiveness and non-invasive nature. Herein, a nano-PROTAC formulation (ARV@PEG-ICG) consisting of a phototherapeutic agent named indocyanine green functionalized polyethylene glycol (PEG-ICG) and a BRD4 degrader (ARV-825) was fabricated for cancer photo-immunotherapy. Activated by acidic tumor microenvironment (TME), ARV@PEG-ICG nanoparticles (NPs) will decompose rapidly for ARV delivery. PEG-ICG generated abundant ROS with laser irradiation, downregulating the expression of Bcl-xL and inducing the cleavage of PARP to stimulate cell apoptosis. Furthermore, the degradation of BRD4, a transcriptional cofactor, inhibited nitric oxide synthase (iNOS) generation to improve phototherapeutic efficacy. In a 4T1 breast tumor model, dying 4T1 cells released tumor associated antigens (TAAs) to serve as the immunogenic cell death (ICD) inducer, facilitating DC maturation and T cell activation and amplifying systemic immune response. The distant tumor growth can also be inhibited due to the activation of long-term immune response. Overall, the current study aims to combine typical PROTAC with functional nanomaterials to form nano-PROTAC with high performance for PROTAC delivery mediated cancer treatment.

De Novo Design of Structure-Tunable Multivalent Targeting Chimeras for Tumor-Targeted PD-L1 Degradation and Potentiated Cancer Immunotherapy

Targeted protein degradation (TPD) technology holds significant potential for modulating protein homeostasis and treating diseases. However, current methods for degrading membrane proteins highly depend on the lysosome-targeting ligands or membrane receptors. In this study, we present a set of multivalent targeting chimeras (multi-TACs) for tumor-specific degradation of programmed death ligand 1 (PD-L1) on the surface of the tumor cell membrane. The multi-TACs are synthesized by copolymerization of small-molecule PD-L1 inhibitor BMS-1 with acid-responsive monomers. The chemical structures of the multi-TACs are optimized by investigating the correlation between PD-L1 degradation efficacy and the key parameters, including acid-sensitive moieties, BMS-1 valency, and spacer length. Mechanistic study reveals that the multi-TACs highly efficiently degrade PD-L1 on the surface of tumor cells via the adsorption-mediated endocytosis and lysosomal degradation pathways, which differ from the reported strategies for membrane protein degradation. The outperformed multi-TAC GG56 with tumor extracellular acidity and enzyme-sensitivity dramatically reduces PD-L1 levels and suppresses tumor growth in mouse models of B16-F10 melanoma and 4T1 breast tumors. Furthermore, GG56 serves as a versatile nanoplatform for combinatory chemo-immunotherapy and radio-immunotherapy of 4T1 breast tumor by co-delivery of chemotherapeutic and radio-sensitizer, respectively.

Chemiluminescence Resonance Energy Transfer for Targeted Photoactivation of Ion Channels in Living Cells

The regulation of oxidative stress in living cells is essential for maintaining cellular processes and signal transduction. However, developing straightforward strategies to activate oxidative stress-sensitive membrane channels in situ poses significant challenges. In this study, we present a chemiluminescence resonance energy transfer (CRET) system based on a conjugated oligomer, oligo(p-phenylenevinylene)-imidazolium (OPV-Im), designed for the activation of transient receptor potential melastatin 2 (TRPM2) calcium channels in situ by superoxide anion (O2⋅-) without requiring external light sources. The OPV-Im oligomer targeted the cell membrane efficiently, leading to the activation of TRPM2 channels in situ by the CRET process and subsequent intracellular calcium overload. This cascade resulted in mitochondrial damage and inhibition of autophagy, ultimately inducing cell apoptosis. Additionally, this strategy could be applied for the selective killing of tumor cells that overexpress TRPM2 ion channels and for inhibiting the growth of three-dimensional (3D) tumor spheroids. Our system offers a novel approach for regulating ion channel activity and oxidative stress in living cells compared to optogenetics and photodynamic therapy.

Bimetallic peroxide-based nanotherapeutics for immunometabolic intervention and induction of immunogenic cell death to augment cancer immunotherapy

Immunotherapy has transformed cancer treatment, but its efficacy is often limited by the immunosuppressive characteristics of the tumor microenvironment (TME), which are predominantly influenced by the metabolism of cancer cells. Among these metabolic pathways, the indoleamine 2,3-dioxygenase (IDO) pathway is particularly crucial, as it significantly contributes to TME suppression and influences immune cell activity. Additionally, inducing immunogenic cell death (ICD) in tumor cells can reverse the immunosuppressive TME, thereby enhancing the efficacy of immunotherapy. Herein, we develop CGDMRR, a novel bimetallic peroxide-based nanodrug based on copper-cerium peroxide nanoparticles. These nanotherapeutics are engineered to mitigate tumor hypoxia and deliver therapeutics such as 1-methyltryptophan (1MT), glucose oxidase (GOx), and doxorubicin (Dox) in a targeted manner. The design aims to alleviate tumor hypoxia, reduce the immunosuppressive effects of the IDO pathway, and promote ICD. CGDMRR effectively inhibits the growth of 4T1 tumors and elicits antitumor immune responses by leveraging immunometabolic interventions and therapies that induce ICD. Furthermore, when CGDMRR is combined with a clinically certified anti-PD-L1 antibody, its efficacy in inhibiting tumor growth is enhanced. This improved efficacy extends beyond unilateral tumor models, also affecting bilateral tumors and lung metastases, due to the activation of systemic antitumor immunity. This study underscores CGDMRR's potential to augment the efficacy of PD-L1 blockade in breast cancer immunotherapy.

Conquering PROTAC molecular design and drugability

PROTACs are reshaping drug discovery by enabling targeted protein degradation, overcoming the limitations of traditional inhibitors, and addressing previously "undruggable" proteins. The present perspective explores advancements in PROTAC molecular design, focusing on ligand discovery, E3 ligase recruitment, and ternary complex optimization. Integrating AI-driven modeling, FBDD, and SBDD accelerates PROTAC development. In contrast, emerging innovations, such as PHOTACs, hypoxia-responsive systems, and Ab-PROTACs, enhance precision and reduce systemic toxicity. Clinical successes, including ARV-110 for castration-resistant prostate cancer and ARV-471 for breast cancer, exemplify their ability to overcome resistance and provide durable effects. PROTACs are expanding into neurodegenerative diseases and rare conditions, highlighting their versatility. By addressing challenges in pharmacokinetics, safety, and scalability, PROTACs are poised to revolutionize precision medicine. This article presents a forward-looking perspective on conquering the molecular design and drugability of PROTACs, paving the path for transformative therapies.

Aggregation induced emission luminogen bacteria hybrid bionic robot for multimodal phototheranostics and immunotherapy

Multimodal phototheranostics utilizing single molecules offer a "one-and-done" approach, presenting a convenient and effective strategy for cancer therapy. However, therapies based on conventional photosensitizers often suffer from limitations such as a single photosensitizing mechanism, restricted tumor penetration and retention, and the requirement for multiple irradiations, which significantly constrain their application. In this report, we present an aggregation-induced emission luminogen (AIEgen) bacteria hybrid bionic robot to address above issues. This bionic robot is composed of multifunctional AIEgen (INX-2) and Escherichia coli Nissle 1917 (EcN), i.e., EcN@INX-2. The EcN@INX-2 bionic robot exhibits near-infrared II (NIR-II) fluorescence emission and demonstrates efficient photodynamic and photothermal effects, as well as tumor-targeting capabilities. These features are facilitated by the complementary roles of INX-2 and EcN. The robot successfully enables in vivo multimodal imaging and therapy of colon cancer models in female mice through various mechanisms, including the activation of anti-tumor immunity, as well as photodynamic and photothermal therapy. Our study paves an avenue for designing multifunctional diagnostic agents for targeted colon cancer therapy through image-guided combinational immunotherapy.

A Dual-Targeted Molecule for Disease-Activatable Proteolysis Targeting Chimeras and Targeted Radionuclide Therapy of Cancer

Proteolysis targeting chimeras (PROTACs) represent a cutting-edge approach for targeted protein degradation in cancer therapy, yet they face challenges such as poor pharmacokinetics and specificity issues, leading to undesirable off-target effects and limited antitumor potency. To address these issues, we introduce dual-targeted unimolecular theranostic probes (e.g., radioactive 177Lu-P-A and its cold counterpart natLu-P-A) for disease-activatable PROTACs in combination with targeted radionuclide therapy (TRT) against prostate cancer with high specificity and effectiveness. The probes achieve a cathepsin B (CTSB)-activatable pro-PROTAC moiety for precise degradation of bromodomain-containing protein 4 (BRD4) and a prostate-specific membrane antigen (PSMA)-targeted 177Lu-based TRT. Owing to the favorable pharmacokinetics and PSMA-mediated excellent targeting efficiency, the probe possesses high tumor imaging specificity and accumulation capacity of therapeutic units for highly effective PROTACs and TRT. In contrast, the free PROTACs unit (e.g., ARV-771) shows no observable therapeutic effect due to its poor targeting ability. Importantly, the BRD4 proteolysis by PROTAC activation can downregulate radiosensitivity-associated RAD51AP1 expression, synergistically enhancing the TRT effect and promoting apoptosis after combined therapy compared to individual treatment regimes. Additionally, the probe demonstrates high renal clearance, underscoring its biosafety for potential clinical translation. This study presents a potential approach for precise PROTACs combined with TRT for effective tumor therapy.

MnO2-Assisted Photosynthetic Bacteria Interfering with the Adenosine-A2AR Metabolic Pathway to Enhance Tumor Photothermal Immunotherapy

Hypoxia-related adenosine (Ado) exerts an immunosuppressive effect in tumors by binding to the metabolic checkpoint Ado A2A receptors (A2AR), thereby hindering the activation of antitumor immunity induced by immunogenic cell death (ICD). In this study, a MnO2-assisted photosynthetic bacteria (PSB) biohybrid (MnO2@PSB) is developed to enhance tumor photothermal immunotherapy by interfering with the Ado-A2AR metabolic pathway. Specifically, manganese dioxide (MnO2) nanoflowers are conjugated onto PSB by the carbodiimide reaction to construct the biohybrid MnO2@PSB. As a photothermal agent, MnO2@PSB generates heat to "burn" tumor cells under 808 nm laser irradiation, inducing tumor cell ICD. Meanwhile, MnO2@PSB catalyzes the decomposition of endogenous hydrogen peroxide into oxygen to alleviate tumor hypoxia, thereby reducing Ado production and downregulating the expression of A2AR, further reversing the tumor immunosuppressive microenvironment and amplifying the ICD effects. In various mouse 4T1 tumor models, MnO2@PSB can enhance antitumor immune responses, prolong mouse survival, and significantly inhibit tumor growth, recurrence, and metastasis under 808 nm laser irradiation. Collectively, this study provides a direction for enhanced antitumor immunotherapy through regulating metabolic pathways.

Perturbing Organelle-Level K+/Ca2+ Homeostasis by Nanotherapeutics for Enhancing Ion-Mediated Cancer Immunotherapy

Intracellular ions are involved in numerous pivotal immune processes, but the precise regulation of these signaling ions to achieve innovative immune therapeutic strategies is still a huge challenge. Here, an ion-mediated immunotherapy agent (IMIA) is engineered to achieve precise spatiotemporal control of perturbing K+/Ca2+ homeostasis at the organelle-level, thereby amplifying antitumor immune responses to achieve high-performance cancer therapy. By taking in intracellular K+ and supplying exogenous Ca2+ within tumor cells, K+/Ca2+ homeostasis is perturbed by IMIA. In parallel, perturbing K+ homeostasis induced endoplasmic reticulum (ER) stress triggers the release of Ca2+ from ER and causes a decreased concentration of Ca2+ in ER, which further accelerates ER-mitochondria Ca2+ flux and the influx of extracellular Ca2+ (store-operated Ca2+ entry (SOCE)) via opening Ca2+ release-activated Ca2+ (CRAC) channels, thus creating a self-amplifying ion interference loop to perturb K+/Ca2+ homeostasis. In this process, the elevated immunogenicity of tumor cells would evoke robust antitumor immune responses by driving the excretion of damage-associated molecular patterns (DAMPs). Importantly, this ion-immunotherapy strategy reshapes the immunosuppressive tumor microenvironment (TME), and awakens the systemic immune response and long-term immune memory effect, thus effectively inhibiting the growth of primary/distant tumors, orthotopic tumors as well as metastatic tumors in different mice models.

Biomimetic polymeric nanoreactors with photooxidation-initiated therapies and reinvigoration of antigen-dependent and antigen-free immunity

Immune cell-mediated anticancer modalities usually suffer from immune cell exhaustion and limited efficacy in solid tumors. Herein, the oxygen-carrying biomimetic nanoreactors (BNR2(O2)) have been developed with photooxidation-driven therapies and antigen-dependent/antigen-free immune reinvigoration against xenograft tumors. The BNR2(O2) composes polymeric nanoreactors camouflaged with cancer cell membranes can efficiently target homotypic tumors. It continuously releases O2 to boost intracellular reactive oxygen species (ROS) to oxide diselenide bonds, which controllably releases seleninic acids and anti-folate Pemetrexed compared to hydrogen peroxide and glutathione incubation. The O2-rich microenvironment sensitizes Pemetrexed and blocks programmed cell-death ligand 1 (PD-L1) to reverse T cell immunosuppression. The ROS and Pemetrexed upregulate pro-apoptosis proteins and inhibit folate-related enzymes, which cause significant apoptosis and immunogenic cell death to stimulate dendritic cell maturation for improved secretion of cytokines, expanding antigen-dependent T cell immunity. Furthermore, by regulating the release of seleninic acids, the checkpoint receptor human leukocyte antigen E of tumor cells can be blocked to reinvigorate antigen-free natural killer cell immunity. This work offers an advanced antitumor strategy by bridging biomimetic nanoreactors and modulation of multiple immune cells.

Prodrug Approach as a Strategy to Enhance Drug Permeability

Absorption and permeability are critical physicochemical parameters that must be balanced to achieve optimal drug uptake. These key factors are closely linked to the maximum absorbable dose required to provide appropriate plasma levels of drugs. Among the various strategies employed to enhance drug solubility and permeability, prodrug design stands out as a highly effective and versatile approach for improving physicochemical properties and enabling the optimization of biopharmaceutical and pharmacokinetic parameters while mitigating adverse effects. Prodrugs are compounds with reduced or no activity that, through bio-reversible chemical or enzymatic processes, release an active parental drug. The application of this technology has led to significant advancements in drug optimization during the design phase, and it offers broad potential for further development. Notably, approximately 13% of the drugs approved by the U.S. Food and Drug Administration (FDA) between 2012 and 2022 were prodrugs. In this review article, we will explore the application of prodrug strategies to enhance permeability, describing examples of market drugs. We also describe the use of the prodrug approach to optimize PROteolysis TArgeting Chimeras (PROTACs) permeability by using conjugation technologies. We will highlight some new technologies in prodrugs to enrich permeability properties, contributing to developing new effective and safe prodrugs.

PROTAC delivery in tumor immunotherapy: Where are we and where are we going?

Immunotherapy has emerged as a pioneering therapeutic modality, particularly within the realm of oncology, where Chimeric Antigen Receptor T-cell (CAR-T) therapy has manifested significant efficacy in the treatment of hematological malignancies. Nonetheless, the extension of immunotherapy to solid tumors poses a considerable challenge. This challenge is largely attributed to the intrinsic "cold" characteristics of certain tumors, which are defined by scant T-cell infiltration and a diminished immune response. Additionally, the impediment is exacerbated by the elusive nature of numerous targets within the tumor microenvironment, notably those deemed "undruggable" by small molecule inhibitors. This scenario underscores an acute necessity for the inception of innovative therapeutic strategies aimed at countering the resistance mechanisms underlying immune evasion in cold tumors, thereby amplifying the efficacy of cancer immunotherapy. Among the promising strategies is the deployment of Proteolysis Targeting Chimeras (PROTACs), which facilitate the targeted degradation of proteins. PROTACs present unique advantages and have become indispensable in oncology. However, they concurrently grapple with challenges such as solubility issues, permeability barriers, and the classical Hook effect. Notably, advanced delivery systems have been instrumental in surmounting these obstacles. This review commences with an analysis of the factors contributing to the suboptimal responses to immunotherapy in cold tumors. Subsequently, it delivers a thorough synthesis of immunotherapeutic concepts tailored for these tumors, clarifying the integral role of PROTACs in their management and delineating the trajectory of PROTAC technology from bench-side investigation to clinical utilization, facilitated by drug delivery systems. Ultimately, the review extrapolates the prospective future of this approach, aspiring to present novel insights that could catalyze progress in immunotherapy for the treatment of cold tumors.

Antitumour vaccination via the targeted proteolysis of antigens isolated from tumour lysates

The activation of cytotoxic T cells against tumour cells typically requires the cross-presentation, by antigen-presenting cells (and via major histocompatibility complex class I molecules), of an epitope derived from a tumour antigen. A critical step in antigen processing is the proteolysis of tumour antigens mediated by the ubiquitin-proteasome pathway. Here we describe a tumour vaccine leveraging targeted antigen degradation to augment antigen processing and cross-presentation. Analogous to proteolysis-targeting chimaeras, the vaccine consists of lymph-node-targeting lipid nanoparticles encapsulated with tumour antigens pre-conjugated with ligands that can bind to E3 ubiquitin ligases. In mice with subcutaneous human melanoma or triple-negative breast cancer, or with orthotopic mouse Lewis lung carcinoma or clinically inoperable mouse ovarian cancer, subcutaneously delivered vaccines prepared using tumour lysate proteins elicited antigen-specific adaptive immunity and immunological memory, and inhibited tumour growth, metastasis and recurrence, particularly when combined with immune checkpoint inhibition.

Self-Assembled Peptide-Derived Proteolysis-Targeting Chimera (PROTAC) Nanoparticles for Tumor-Targeted and Durable PD-L1 Degradation in Cancer Immunotherapy

Proteolysis-targeting chimeras (PROTACs) are a promising technique for the specific and durable degradation of cancer-related proteins via the ubiquitin-proteasome system in cancer treatment. However, the therapeutic efficacy of PROTACs is restricted due to their hydrophobicity, poor cell permeability and insufficient tumor-targeting ability. Herein, we develop the self-assembled peptide-derived PROTAC nanoparticles (PT-NPs) for precise and durable programmed death-ligand 1 (PD-L1) degradation in targeted tumors. The PT-NPs with an average size of 211.8 nm are formed through the self-assembly of amphiphilic peptide-derived PROTAC (CLQKTPKQC-FF-ALAPYIP), comprising a PD-L1-targeting 'CLQKTPKQC', self-assembling linker 'FF' and E3 ligase recruiting 'ALAPYIP'. Particularly, PT-NPs strongly bind to tumor cell surface PD-L1 to form PD-L1/PT-NPs complex, then internalized through receptor-mediated endocytosis and degraded in lysosomes. Second, free PROTACs released from PT-NPs to the cytoplasm further induce the durable proteolysis of cytoplasmic PD-L1 via the ubiquitin-proteasome system. In colon tumor models, intravenously injected PT-NPs accumulate significantly at targeted tumor tissues through nanoparticle-derived passive and active targeting. At the targeted tumor tissues, PT-NPs promote durable PD-L1 degradation and ultimately trigger a substantial antitumor immune response. Collectively, this study provides valuable insights into the rational design of self-assembled peptide-derived PROTAC nanoparticles to ensure noticeable accuracy and enhanced efficacy in cancer treatment.

Nanomaterial-enabled metabolic reprogramming strategies for boosting antitumor immunity

Immunotherapy has become a crucial strategy in cancer treatment, but its effectiveness is often constrained. Most cancer immunotherapies focus on stimulating T-cell-mediated immunity by driving the cancer-immunity cycle, which includes tumor antigen release, antigen presentation, T cell activation, infiltration, and tumor cell killing. However, metabolism reprogramming in the tumor microenvironment (TME) supports the viability of cancer cells and inhibits the function of immune cells within this cycle, presenting clinical challenges. The distinct metabolic needs of tumor cells and immune cells require precise and selective metabolic interventions to maximize therapeutic outcomes while minimizing adverse effects. Recent advances in nanotherapeutics offer a promising approach to target tumor metabolism reprogramming and enhance the cancer-immunity cycle through tailored metabolic modulation. In this review, we explore cutting-edge nanomaterial strategies for modulating tumor metabolism to improve therapeutic outcomes. We review the design principles of nanoplatforms for immunometabolic modulation, key metabolic pathways and their regulation, recent advances in targeting these pathways for the cancer-immunity cycle enhancement, and future prospects for next-generation metabolic nanomodulators in cancer immunotherapy. We expect that emerging immunometabolic modulatory nanotechnology will establish a new frontier in cancer immunotherapy in the near future.

MicroRNA-Triggered Programmable DNA-Encoded Pre-PROTACs for Cell-Selective and Controlled Protein Degradation

Proteolysis-targeting chimeras (PROTACs) have accelerated drug development; however, some challenges still exist owing to their lack of tumor selectivity and on-demand protein degradation. Here, we developed a miRNA-initiated assembled pre-PROTAC (miRiaTAC) platform that enables the on-demand activation and termination of target degradation in a cell type-specific manner. Using miRNA-21 as a model, we engineered DNA hairpins labeled with JQ-1 and pomalidomide and facilitated the modular assembly of DNA-encoded pre-PROTACs through a hybridization chain reaction. This configuration promoted the selective polyubiquitination and degradation of BRD4 upon miR-21 initiation, highlighting significant tumor selectivity and minimal systemic toxicity. Furthermore, the platform incorporates photolabile groups, enabling the precise optical control of pre-PROTACs during DNA assembly/disassembly, mitigating the risk of excessive protein degradation. Additionally, by introducing a secondary ligand targeting CDK6, these pre-PROTACs were used as a modular scaffold for the programmable assembly of active miRiaTACs containing two different warheads in exact stoichiometry, enabling orthogonal multitarget degradation. The integration of near-infrared light-mediated photodynamic therapy through an upconversion nanosystem further enhanced the efficacy of the platform with potent in vivo anticancer activity. We anticipate that miRiaTAC represents a significant intersection between dynamic DNA nanotechnology and PROTAC, potentially expanding the versatility of PROTAC toolkit for cancer therapy.

Epigenetics disruptions enabled by porphyrin-derived metal-organic frameworks disarm resistances to sonocatalytic ROS anti-tumor actions

Post-transcriptional epigenetic modifications provide numerous implications for tumor progression, metastasis and recurrence, which also pose resistances to reactive oxygen species (ROS)-based anti-tumor. Herein, we proposed an epigenetic deubiquitination disruption strategy to disarm the ubiquitination-deubiquitination balance-induced resistances to ROS production and ROS-based anti-tumor action for potentiating sonodynamic treatment (SDT) efficiency. To end it, porphyrin-derived metal-organic framework (MOF) sonocatalytic nanoplatforms were developed to load deubiquitination inhibitors (i.e., Auranofin). Ultrasound-triggered Auranofin release from PCN224@Au has been validated to blockade the deubiquitinating process and drive proteasome-mediated target protein degradation. The epigenetic deubiquitination disruption not only synergized with MOF-mediated sonocatalytic ROS production, but also inactivate deubiquitinating enzymes, blockade the deubiquitination process and further remove these resistances, both of which mutually behaved as reciprocal impetuses to significantly magnify SDT outcomes against liver cancers. Such a deubiquitination-engineered disruption approach finds an unprecedented pathway to disarm deubiquitination-induced resistances to SDT and other ROS-based anti-tumor means, which also enlightens us to establish other post-transcriptional epigenetic modification disruption strategies to re-program the tumor microenvironment and elevate the anti-tumor efficiency of various treatment methods (e.g., immunotherapy).

Synergistic Degradation of Durable Polymer Networks by Light and Acid Enabled by Pyrenylsilicon Crosslinks

Material photocontrol has gained importance in process engineering and biomedical applications. However, highly photoreactive materials are intrinsically unstable to light, which limits their continuous use in lit environments owing to their gradual deterioration. Herein, synergistically photocontrollable materials in the presence of acid are developed to overcome the conventional trade-off between their photoreactivity and photostability. Pyrenylsilicon derivatives are designed as synergistically cleavable moieties on C-Si bonds under simultaneous treatment with light and acid through photoinduced dearomatization and protonation to generate the Wheland intermediate, whereas the derivatives are highly stable to light or acid alone. The unique reactivity of pyrenylsilicon derivatives is applied to various polymer network crosslinkers, enabling synergistic control and degradation of materials with light and acids. Because of their high photostability in the absence of acids, these materials can be utilized as optical materials, robust elastomers, and 3D photoprinted gels.

Intratumoral lactic acid neutralization strategy for boosting chemoimmunotherapy using liposomal sodium bicarbonate

Glycolysis-related lactic acid overproduction creates an "ion-trapping" barrier and immunosuppressive tumor microenvironment that compromise effective intratumoral drug delivery and therapy. Therefore, normalization of tumor microenvironment via lactic acid neutralization can be a promising avenue for overcoming this therapeutic hurdle. In this study, the flexible liposomes loaded with sodium bicarbonate (NaHCO3@Flip) were used as a nano-adjuvant to boost chemoimmunotherapy. Their effects on assisting DOXIL and anti-programmed cell death protein 1 (PD-1) therapy were investigated. NaHCO3@Flip achieved deep tumor penetration, with the ability to neutralize lactic acid and normalize the acidic tumor microenvironment. NaHCO3@Flip is biosafe and can enhance cellular uptake efficiency of doxorubicin (DOX) by overcoming the ion-trapping barrier and amplify immunogenic cell death induced by DOX. The combination therapy of liposomal DOX and NaHCO3@Flip demonstrated enhanced inhibition of tumor growth. NaHCO3@Flip can also synergize with PD-1 antibody therapy. NaHCO3@Flip has the potential to serve as a therapeutic adjuvant for boosting chemoimmunotherapy by overcoming the ion-trapping effect and normalizing the tumor microenvironment.

Modularity-based mathematical modeling of ligand inter-nanocluster connectivity for unraveling reversible stem cell regulation

The native extracellular matrix is continuously remodeled to form complex interconnected network structures that reversibly regulate stem cell behaviors. Both regulation and understanding of its intricate dynamicity can help to modulate numerous cell behaviors. However, neither of these has yet been achieved due to the lack of designing and modeling such complex structures with dynamic controllability. Here we report modularity-based mathematical modeling of extracellular matrix-emulating ligand inter-cluster connectivity using the graph theory. Increasing anisotropy of magnetic nano-blockers proportionately disconnects arginine-glycine-aspartic acid ligand-to-ligand interconnections and decreases the number of ligand inter-cluster edges. This phenomenon deactivates stem cells, which can be partly activated by linearizing the nano-blockers. Remote cyclic elevation of high-anisotropy nano-blockers flexibly generates nano-gaps under the nano-blockers and augments the number of ligand inter-cluster edges. Subsequently, integrin-presenting stem cell infiltration is stimulated, which reversibly intensifies focal adhesion and mechanotransduction-driven differentiation both in vitro and in vivo. Designing and systemically modeling extracellular matrix-mimetic geometries opens avenues for unraveling dynamic cell-material interactions for tissue regeneration.

Sonodynamic Nano-LYTACs Reverse Tumor Immunosuppressive Microenvironment for Cancer Immunotherapy

Extracellular and transmembrane proteins, which account for the products of approximately 40% of all protein-encoding genes in tumors, play a crucial role in shaping the tumor immunosuppressive microenvironment (TIME). While protein degradation therapy has been applied to membrane proteins of cancer cells, it has rarely been extended to immune cells. We herein report a polymeric nanolysosome targeting chimera (nano-LYTAC) that undergoes membrane protein degradation on M2 macrophages and generates a sonodynamic effect for combinational cancer immunotherapy. Nano-LYTAC is found to have higher degradation efficacy to the interleukin 4 receptor (IL-4R) compared to traditional inhibitors. More importantly, it is revealed that the effect of nano-LYTAC on the function of the M2 macrophage is concentration-dependent: downregulating CD206 expression and interleukin 10 (IL-10) secretion from M2 macrophages at low concentration, while triggering their apoptosis at high concentration. Moreover, nano-LYTAC is found to possess long tumor retention (>48 h), allowing for multiple sonodynamic treatments with a single dose. Such a synergistic sonodynamic immunotherapy mediated by nano-LYTAC effectively reprograms the TIME via inhibiting the functions of M2 macrophages and regulatory T cells (Tregs), as well as promoting the maturation of dendritic cells (DCs) and tumor infiltration of T effector cells (Teffs), completely suppressing tumor growth, inhibiting pulmonary metastasis, and preventing recurrence under preclinical animal models.

NIR-II AIEgens for Infectious Diseases Phototheranostics

Pathogenic infectious diseases have persistently posed significant threats to public health. Phototheranostics, which combines the functions of diagnostic imaging and therapy, presents an extremely promising solution to block the spread of pathogens as well as the outbreak of epidemics owing to its merits of a wide-spectrum of activity, high controllability, non-invasiveness, and difficult to acquire resistance. Among multifarious phototheranostic agents, second near-infrared (NIR-II, 1000-1700 nm) aggregation-induced emission luminogens (AIEgens) are notable by virtue of their deep penetration depth, excellent biocompatibility, balanced radiative and nonradiative decay and aggregation-enhanced theranostic performance, making them an ideal option for combating pathogens. This minireview provides a systematical summary of the latest advancements in NIR-II AIEgens with emphasis on the molecular design and nanoplatform formulation to fulfill high-efficiency in treating bacterial and viral pathogens, classified by disease models. Then, the current challenges, potential opportunities, and future research directions are presented to facilitate the further progress of this emerging field.

A new era of cancer phototherapy: mechanisms and applications

The past decades have witnessed great strides in phototherapy as an experimental option or regulation-approved treatment in numerous cancer indications. Of particular interest is nanoscale photosensitizer-based phototherapy, which has been established as a prominent candidate for advanced tumor treatment by virtue of its high efficacy and safety. Despite considerable research progress on materials, methods and devices in nanoscale photosensitizing agent-based phototherapy, their mechanisms of action are not always clear, which impedes their practical application in cancer treatment. Hence, from a new perspective, this review elaborates the working mechanisms, involving impairment and moderation effects, of diverse phototherapies on cells, organelles, organs, and tissues. Furthermore, the most current available phototherapy modalities are categorized as photodynamic, photothermal, photo-immune, photo-gas, and radio therapies in this review. A comprehensive understanding of the inferiority and superiority of various phototherapies will facilitate the advent of a new era of cancer phototherapy.

Nanoscale covalent organic framework-mediated pyroelectrocatalytic activation of immunogenic cell death for potent immunotherapy

The conventional molecular immunogenic cell death (ICD) inducers suffer from poor biocompatibility and unsatisfactory efficacy. Here, a biocompatible nanosized covalent organic framework (nCOF)-based pyroelectric catalyst (denoted as TPAD-COF NPs) is designed for pyroelectric catalysis-activated in situ immunotherapy. TPAD-COF NPs confine organic pyroelectric molecules to rigid TPAD-COF NPs to substantially reduce aggregation and enhance biocompatibility, thus improving pyroelectrocatalytic efficiency. After tumor internalization, TPAD-COF NPs facilitate photothermal tumor ablation under near-infrared (NIR) laser exposure, resulting in effective ICD induction. In addition, TPAD-COF NPs effectively catalyze the conversion of temperature changes to pyroelectric changes, which subsequently react with adjacent O2 to generate reactive oxygen species, thus triggering robust ICD activation. In vivo evaluation using mouse models confirmed that TPAD-COF NPs evidently inhibited the proliferation of primary and distant tumors and prevented lung metastasis under NIR laser illumination. Therefore, this study opens an avenue for designing nCOF-based catalysts for pyroelectric catalysis-activated in situ immunotherapy.

Precision-engineered PROTACs minimize off-tissue effects in cancer therapy

Proteolysis-targeting chimeras (PROTACs) offer a groundbreaking approach to selectively degrade disease-related proteins by utilizing the ubiquitin-proteasome system. While this strategy shows great potential in preclinical and clinical settings, off-tissue effects remain a major challenge, leading to toxicity in healthy tissues. This review explores recent advancements aimed at improving PROTAC specificity, including tumor-specific ligand-directed PROTACs, pro-PROTACs activated in tumor environments, and E3 ligase overexpression strategies. Innovations such as PEGylation and nanotechnology also play a role in optimizing PROTAC efficacy. These developments hold promise for safer, more effective cancer therapies, though challenges remain for clinical translation.

Conditional PROTAC: Recent Strategies for Modulating Targeted Protein Degradation

Proteolysis-targeting chimeras (PROTACs) have emerged as a promising technology for inducing targeted protein degradation by leveraging the intrinsic ubiquitin-proteasome system (UPS). While the potential druggability of PROTACs toward undruggable proteins has accelerated their rapid development and the wide-range of applications across diverse disease contexts, off-tissue effects and side-effects of PROTACs have recently received attentions to improve their efficacy. To address these issues, spatial or temporal target protein degradation by PROTACs has been spotlighted. In this review, we explore chemical strategies for modulating protein degradation in a cell type-specific (spatio-) and time-specific (temporal-) manner, thereby offering insights for expanding PROTAC applications to overcome the current limitations of target protein degradation strategy.

Dual targeting and bioresponsive nano-PROTAC induced precise and effective lung cancer therapy

Epigenetic regulation has emerged as a promising therapeutic strategy for lung cancer treatment, which can facilitate the antitumor responses by modulating epigenetic dysregulation of target proteins in lung cancer. The proteolysis-targeting chimera (PROTAC) reagent, dBET6 shows effective inhibition of bromodomain-containing protein 4 (BRD4) that exerts antitumor efficacy by degrading BRD4 via the ubiquitin-proteasome system. Nevertheless, the low tissue specificity and bioavailability impede its therapeutic effects and clinical translation on lung cancer treatment. Herein, we developed a type of dual targeting and bioresponsive nano-PROTAC (c R GD/L LC membrane/D S-P LGA/d B ET6, named RLDPB), which was constructed by using the pH and glutathione (GSH)-responsive polymer, disulfide bond-linked poly(lactic-co-glycolic acid) (PLGA-S-S-PLGA, DS-PLGA) to load the PROTAC agent dBET6, and further camouflaged with the homotypic LLC cell membranes, followed by the conjugation with cRGD ligand to the surface of the nanoparticles. Notably, RLDPB showed enhanced celluar uptake by lung cancer cells in vitro and accumulation in the tumors via the dual targeting structure including cRGD and LLC membrane. The pH/GSH responsiveness improved the release of dBET6 from the DS-PLGA-based nanoparticles within the cells. RLDPB was demonstrated to facilitate tumor regression by inducing the apoptosis of lung cancer cells with the degradation of BRD4. Thus, RLDPB can be considered a powerful tool to suppress lung cancer, which opens a new avenue to treat lung cancer by PROTAC.

Recent breakthroughs in innovative elements, multidimensional enhancements, derived technologies, and novel applications of PROTACs

Proteolysis Targeting Chimera (PROTAC) is an emerging and evolving technology based on targeted protein degradation (TPD). Small molecule PROTACs have shown great efficacy in degrading disease-specific proteins in preclinical and clinical studies, but also showed various limitations. In recent years, new technologies and advances in TPD have provided additional optimized strategies based on conventional PROTACs that can overcome the shortcomings of conventional PROTACs in terms of undruggable targets, bioavailability, tissue-specificity, spatiotemporal control, and degradation scope. In addition, some designs of special targeting chimeras and applications based on multidisciplinary science have shed light on novel therapeutic modalities and drug design. However, each improvement has its own advantages, disadvantages and application conditions. In this review, we summarize the exploration of PROTAC elements, depict a landscape of improvements and derived concepts of PROTACs, and expect to provide perspectives for technological innovations, combinations and applications in future targeting chimera design.

Advancing Proteolysis Targeting Chimera (PROTAC) Nanotechnology in Protein Homeostasis Reprograming for Disease Treatment

Proteolysis targeting chimeras (PROTACs) represent a transformative class of therapeutic agents that leverage the intrinsic protein degradation machinery to modulate the hemostasis of key disease-associated proteins selectively. Although several PROTACs have been approved for clinical application, suboptimal therapeutic efficacy and potential adverse side effects remain challenging. Benefiting from the enhanced targeted delivery, reduced systemic toxicity, and improved bioavailability, nanomedicines can be tailored with precision to integrate with PROTACs which hold significant potential to facilitate PROTAC nanomedicines (nano-PROTACs) for clinical translation with enhanced efficacy and reduced side effects. In this review, we provide an overview of the recent progress in the convergence of nanotechnology with PROTAC design, leveraging the inherent properties of nanomaterials, such as lipids, polymers, inorganic nanoparticles, nanohydrogels, proteins, and nucleic acids, for precise PROTAC delivery. Additionally, we discuss the various categories of PROTAC targets and provide insights into their clinical translational potential, alongside the challenges that need to be addressed.

Sequential responsive nano-PROTACs for precise intracellular delivery and enhanced degradation efficacy in colorectal cancer therapy

PROteolysis TArgeting Chimeras (PROTACs) have been considered the next blockbuster therapies. However, due to their inherent limitations, the efficacy of PROTACs is frequently impaired by limited tissue penetration and particularly insufficient cellular internalization into their action sites. Herein, based on the ultra-pH-sensitive and enzyme-sensitive nanotechnology, a type of polymer PROTAC conjugated and pH/cathepsin B sequential responsive nanoparticles (PSRNs) are deliberately designed, following the construction of the PROTAC for Cyclin-dependent kinase 4 and 6 (CDK4/6). Colorectal cancer (CRC) which hardly responds to many treatments even immune checkpoint blockades was selected as the tumor model in this study. As a result, PSRNs were found to maintain nanostructure (40 nm) in circulation and efficiently accumulated in tumors via enhanced permeation and retention effect. Then, they were dissociated into unimers (<10 nm) in response to an acidic tumor microenvironment, facilitating tumor penetration and cellular internalization. Eventually, the CDK4/6 degrading PROTACs were released intracellularly following the cleavage of cathepsin B. Importantly, PSRNs led to the enhanced degradation of target protein in vitro and in vivo. The degradation of CDK4/6 also augmented the efficacy of immune checkpoint blockades, through the upregulation of programmed cell death-ligand 1 (PD-L1) expression in cancer cells and the suppression of regulatory T cells cell proliferation in tumor microenvironment. By combination with α-PD-1, an enhanced anti-tumor outcome is well achieved in CT26 tumor model. Overall, our study verifies the significance of precise intracellular delivery of PROTACs and introduces a promising therapeutic strategy for the targeted combination treatment of CRC.

Proteolysis-targeting drug delivery system (ProDDS): integrating targeted protein degradation concepts into formulation design

Targeted protein degradation (TPD) has emerged as a revolutionary paradigm in drug discovery and development, offering a promising avenue to tackle challenging therapeutic targets. Unlike traditional drug discovery approaches that focus on inhibiting protein function, TPD aims to eliminate proteins of interest (POIs) using modular chimeric structures. This is achieved through the utilization of proteolysis-targeting chimeras (PROTACs), which redirect POIs to E3 ubiquitin ligases, rendering them for degradation by the cellular ubiquitin-proteasome system (UPS). Additionally, other TPD technologies such as lysosome-targeting chimeras (LYTACs) and autophagy-based protein degraders facilitate the transportation of proteins to  endo-lysosomal or autophagy-lysosomal pathways for degradation, respectively. Despite significant growth in preclinical TPD research, many chimeras fail to progress beyond this stage in the drug development. Various factors contribute to the limited success of TPD agents, including a significant hurdle of inadequate delivery to the target site. Integrating TPD into delivery platforms could surmount the challenges of in vivo applications of TPD strategies by reshaping their pharmacokinetics and pharmacodynamic profiles. These proteolysis-targeting drug delivery systems (ProDDSs) exhibit superior delivery performance, enhanced targetability, and reduced off-tissue side effects. In this review, we will survey the latest progress in TPD-inspired drug delivery systems, highlight the importance of introducing delivery ideas or technologies to the development of protein degraders, outline design principles of protein degrader-inspired delivery systems, discuss the current challenges, and provide an outlook on future opportunities in this field.

Platelet-Drug Conjugates Engineered via One-step Fusion Approach for Metastatic and Postoperative Cancer Treatment

The exploration of cell-based drug delivery systems for cancer therapy has gained growing attention. Approaches to engineering therapeutic cells with multidrug loading in an effective, safe, and precise manner while preserving their inherent biological properties remain of great interest. Here, we report a strategy to simultaneously load multiple drugs in platelets in a one-step fusion process. We demonstrate doxorubicin (DOX)-encapsulated liposomes conjugated with interleukin-15 (IL-15) could fuse with platelets to achieve both cytoplasmic drug loading and surface cytokine modification with a loading efficiency of over 70 % within minutes. Due to their inherent targeting ability to metastatic cancers and postoperative bleeding sites, the engineered platelets demonstrated a synergistic therapeutic effect to suppress lung metastasis and postoperative recurrence in mouse B16F10 melanoma tumor models.

Light-Triggered PROTAC Nanoassemblies for Photodynamic IDO Proteolysis in Cancer Immunotherapy

While proteolysis-targeting chimeras (PROTACs) hold great potential for persistently reprogramming the immunosuppressive tumor microenvironment via targeted protein degradation, precisely activating them in tumor tissues and preventing uncontrolled proteolysis at off-target sites remain challenging. Herein, a light-triggered PROTAC nanoassembly (LPN) for photodynamic indoleamine 2,3-dioxygenase (IDO) proteolysis is reported. The LPN is derived from the self-assembly of prodrug conjugates, which comprise a PROTAC, cathepsin B-specific cleavable peptide linker, and photosensitizer, without any additional carrier materials. In colon tumor models, intravenously injected LPNs initially silence the activity of PROTACs and accumulate significantly in targeted tumor tissues due to an enhanced permeability and retention effect. Subsequently, the cancer biomarker cathepsin B begins to trigger the release of active PROTACs from the LPNs through enzymatic cleavage of the linkers. Upon light irradiation, tumor cells undergo immunogenic cell death induced by photodynamic therapy to promote the activation of effector T cells, while the continuous IDO degradation of PROTAC simultaneously blocks tryptophan metabolite-regulated regulatory-T-cell-mediated immunosuppression. Such LPN-mediated combinatorial photodynamic IDO proteolysis effectively inhibits tumor growth, metastasis, and recurrence. Collectively, this study presents a promising nanomedicine, designed to synergize PROTACs with other immunotherapeutic modalities, for more effective and safer cancer immunotherapy.

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.

Optimized Bionic Drug-Delivery-Inducing Immunogenic Cell Death and cGAS-STING Pathway Activation for Enhanced Photodynamic-Chemotherapy-Driven Immunotherapy in Prostate Cancer

Prostate cancer presents as a challenging disease, as it is often characterized as an immunologically "cold" tumor, leading to suboptimal outcomes with current immunotherapeutic approaches in clinical settings. Photodynamic therapy (PDT) harnesses reactive oxygen species generated by photosensitizers (PSs) to disrupt the intracellular redox equilibrium. This process induces DNA damage in both the mitochondria and nucleus, activating the process of immunogenic cell death (ICD) and the cGAS-STING pathway. Ultimately, this cascade of events leads to the initiation of antitumor immune responses. Nevertheless, existing PSs face challenges, including suboptimal tumor targeting, aggregation-induced quenching, and insufficient oxygen levels in the tumor regions. To this end, a versatile bionic nanoplatform has been designed for the simultaneous delivery of the aggregation-induced emission PS TPAQ-Py-PF6 and paclitaxel (PTX). The cell membrane camouflage of the nanoplatform leads to its remarkable abilities in tumor targeting and cellular internalization. Upon laser irradiation, the utilization of TPAQ-Py-PF6 in conjunction with PTX showcases a notable and enhanced synergistic antitumor impact. Additionally, the nanoplatform has the capability of initiating the cGAS-STING pathway, leading to the generation of cytokines. The presence of damage-associated molecular patterns induced by ICD collaborates with these aforementioned cytokines lead to the recruitment and facilitation of dendritic cell maturation. Consequently, this elicits a systemic immune response against tumors. In summary, this promising strategy highlights the use of a multifunctional biomimetic nanoplatform, combining chemotherapy, PDT, and immunotherapy to enhance the effectiveness of antitumor treatment.

Targeted Protein Degradation (TPD) for Immunotherapy: Understanding Proteolysis Targeting Chimera-Driven Ubiquitin-Proteasome Interactions

Targeted protein degradation or TPD, is rapidly emerging as a treatment that utilizes small molecules to degrade proteins that cause diseases. TPD allows for the selective removal of disease-causing proteins, including proteasome-mediated degradation, lysosome-mediated degradation, and autophagy-mediated degradation. This approach has shown great promise in preclinical studies and is now being translated to treat numerous diseases, including neurodegenerative diseases, infectious diseases, and cancer. This review discusses the latest advances in TPD and its potential as a new chemical modality for immunotherapy, with a special focus on the innovative applications and cutting-edge research of PROTACs (Proteolysis TArgeting Chimeras) and their efficient translation from scientific discovery to technological achievements. Our review also addresses the significant obstacles and potential prospects in this domain, while also offering insights into the future of TPD for immunotherapeutic applications.

Catalytic NIR chemiluminescence sensor with enhanced persistence and intensity for in vivo imaging

Chemiluminescence (CL) is a self-illumination phenomenon that involves the emission of light from chemical reactions, and it provides favorable spatial and temporal information on biological processes. However, it is still a great challenge to construct effective CL sensors that equip strong CL intensity, long emission wavelength, and persistent luminescence for deep tissue imaging. Here, we report a liposome encapsulated polymer dots (Pdots)-based system using catalytic CL substrates (L-012) as energy donor and fluorescent polymers and dyes (NIR 695) as energy acceptors for efficient Near-infrared (NIR) CL in vivo imaging. Thanks to the modulation of paired donor and acceptor distance and the slow diffusion of biomarker by liposome, the Pdots show a NIR emission wavelength (λ em, max = 720 nm), long CL duration (>24 h), and a high chemiluminescence resonance energy transfer efficiency (46.5 %). Furthermore, the liposome encapsulated Pdots possess excellent biocompatibility, sensitive response to H2O2, and persistent whole-body NIR CL imaging in the drug-induced inflammation and the peritoneal metastatic tumor mouse model. In a word, this NIR-II CL nanoplatform with long-lasting emission and high spatial-temporal resolution will be a concise strategy in deep tissue imaging and clinical diagnostics.

Metal-Phenolic Nanomaterial with Organelle-Level Precision Primes Antitumor Immunity via mtDNA-dependent cGAS-STING Activation

New generation of nanomaterials with organelle-level precision provide significant promise for targeted attacks on mitochondria, exhibiting remarkable therapeutic potency. Here, we report a novel amphiphilic phenolic polymer (PF) for the mitochondria-targeted photodynamic therapy (PDT), which can trigger excessive mitochondrial DNA (mtDNA) damage by the synergistic action of oxidative stress and furan-mediated DNA cross-linking. Moreover, the phenolic units on PF enable further self-assembly with Mn2+ via metal-phenolic coordination to form metal-phenolic nanomaterial (PFM). We focus on the synergistic activation of the cGAS-STING pathway by Mn2+ and tumor-derived mtDNA in tumor-associated macrophages (TAMs), and subsequently repolarizing M2-like TAMs to M1 phenotype. We highlight that PFM facilitates the cGAS-STING-dependent immunity at the organelle level for potent antitumor efficacy.

A Pyroptosis-Inducing Arsenic(III) Nanomicelle Platform for Synergistic Cancer Immunotherapy

Immunogenic cell death (ICD) could activate anti-tumor immune responses, which is highly attractive for improving cancer treatment effectiveness. Here, this work reports a multifunctional arsenic(III) allosteric inhibitor Mech02, which induces excessive accumulation of 1O2 through sensitized biocatalytic reactions, leading to cell pyroptosis and amplified ICD effect. After Mech02 is converted to Mech03, it could actualize stronger binding effects on the allosteric pocket of pyruvate kinase M2, further interfering with the anaerobic glycolysis pathway of tumors. The enhanced DNA damage triggered by Mech02 and the pyroptosis of cancer stem cells provide assurance for complete tumor clearance. In vivo experiments prove nanomicelle Mech02-HA NPs is able to activate immune memory effects and raise the persistence of anti-tumor immunity. In summary, this study for the first time to introduce the arsenic(III) pharmacophore as an enhanced ICD effect initiator into nitrogen mustard, providing insights for the development of efficient multimodal tumor therapy agents.

A near-infrared broad-spectrum antimicrobial nanoplatform powered by bacterial metabolic activity for enhanced antimicrobial photodynamic-immune therapy

The emergence of antimicrobial-resistant bacterial infections poses a significant threat to public health, necessitating the development of innovative and effective alternatives to antibiotics. Photodynamic therapy (PDT) and immunotherapy show promise in combating bacteria. However, PDT's effectiveness is hindered by its low specificity to bacteria, while immunotherapy struggles to eliminate bacteria in immunosuppressive environments. In this work, we introduce an innovative near-infrared antimicrobial nanoplatform (ZFC) driven by bacterial metabolism. ZFC, comprising d-cysteine-functionalized pentafluorophenyl bacteriochlorin (FBC-Cy) coordinated with Zn2+, is designed for antimicrobial photodynamic-immune therapy (aPIT) against systemic bacterial infections. By specifically targeting bacteria via d-amino acid incorporation into bacterial surface peptidoglycans during metabolism, ZFC achieves precise bacterial clearance in wound and pulmonary infections, exhibiting an antimicrobial efficacy of up to 90 % with minimal damage to normal cells under 750 nm light. Additionally, ZFC enhances the activation of antigen-presenting cells by 3.2-fold compared to control groups. Furthermore, aPIT induced by ZFC triggers systemic immune responses and establishes immune memory, resulting in a 1.84-fold increase in antibody expression against bacterial infections throughout the body of mice. In conclusion, aPIT prompted by ZFC presents a approach to treating bacterial infections, offering a broad-spectrum solution for systemic bacterial infections. STATEMENT OF SIGNIFICANCE: The new concept demonstrated focuses on an innovative near-infrared antimicrobial nanoplatform (ZFC) for antimicrobial photodynamic-immune therapy (aPIT), highlighting its reliance on bacterial metabolism and its non-damaging effect on normal tissues. ZFC efficiently targets deep-tissue bacterial infections by harnessing bacterial metabolism, thereby enhancing therapeutic efficacy while sparing normal tissues from harm. This approach not only clears bacterial infections effectively but also induces potent adaptive immune responses, leading to the eradication of distant bacterial infections. By emphasizing ZFC's unique mechanism driven by bacterial metabolism and its tissue-sparing properties, this work underscores the potential for groundbreaking advancements in antimicrobial therapy. Such advancements hold promise for minimizing collateral damage to healthy tissues, thereby improving treatment outcomes and mitigating the threat of antimicrobial resistance. This integrated approach represents a significant progress forward in the development of next-generation antimicrobial therapies with enhanced precision and efficacy.

Progress of proteolysis-targeting chimeras (PROTACs) delivery system in tumor treatment

Proteolysis targeting chimeras (PROTACs) can use the intrinsic protein degradation system in cells to degrade pathogenic target proteins, and are currently a revolutionary frontier of development strategy for tumor treatment with small molecules. However, the poor water solubility, low cellular permeability, and off-target side effects of most PROTACs have prevented them from passing the preclinical research stage of drug development. This requires the use of appropriate delivery systems to overcome these challenging hurdles and ensure precise delivery of PROTACs towards the tumor site. Therefore, the combination of PROTACs and multifunctional delivery systems will open up new research directions for targeted degradation of tumor proteins. In this review, we systematically reviewed the design principles and the most recent advances of various PROTACs delivery systems. Moreover, the constructive strategies for developing multifunctional PROTACs delivery systems were proposed comprehensively. This review aims to deepen the understanding of PROTACs drugs and promote the further development of PROTACs delivery system.

Tumor-targeted PROTAC prodrug nanoplatform enables precise protein degradation and combination cancer therapy

Proteolysis targeting chimeras (PROTACs) have emerged as revolutionary anticancer therapeutics that degrade disease-causing proteins. However, the anticancer performance of PROTACs is often impaired by their insufficient bioavailability, unsatisfactory tumor specificity and ability to induce acquired drug resistance. Herein, we propose a polymer-conjugated PROTAC prodrug platform for the tumor-targeted delivery of the most prevalent von Hippel-Lindau (VHL)- and cereblon (CRBN)-based PROTACs, as well as for the precise codelivery of a degrader and conventional small-molecule drugs. The self-assembling PROTAC prodrug nanoparticles (NPs) can specifically target and be activated inside tumor cells to release the free PROTAC for precise protein degradation. The PROTAC prodrug NPs caused more efficient regression of MDA-MB-231 breast tumors in a mouse model by degrading bromodomain-containing protein 4 (BRD4) or cyclin-dependent kinase 9 (CDK9) with decreased systemic toxicity. In addition, we demonstrated that the PROTAC prodrug NPs can serve as a versatile platform for the codelivery of a PROTAC and chemotherapeutics for enhanced anticancer efficiency and combination benefits. This study paves the way for utilizing tumor-targeted protein degradation for precise anticancer therapy and the effective combination treatment of complex diseases.

Eosinophil-Activating Semiconducting Polymer Nanoparticles for Cancer Photo-Immunotherapy

Eosinophils are important immune effector cells that affect T cell-mediated antitumor immunity. However, the low frequency and restrained activity of eosinophils restricted the outcome of cancer immunotherapies. We herein report an eosinophil-activating semiconducting polymer nanoparticle (SPNe) to improve photodynamic tumor immunogenicity, modulate eosinophil chemotaxis, and reinvigorate T-cell immunity for activated cancer photo-immunotherapy. SPNe comprises an amphiphilic semiconducting polymer and a dipeptidyl peptidase 4 (DPP4) inhibitor sitagliptin via a 1O2-cleavable thioketal linker. Upon localized NIR photoirradiation, SPNe generates 1O2 to elicit immunogenic cell death of tumors and induce specific activation of sitagliptin. The subsequent inhibition of DPP4 increases intratumoral CCL11 levels to promote eosinophil chemotaxis and activation. SPNe-mediated photo-immunotherapy synergized with immune checkpoint blockade greatly promotes tumor infiltration and activation of both eosinophils and T cells, effectively inhibiting tumor growth and metastasis. Thus, this study presents a generic polymeric nanoplatform to modulate specific immune cells for precision cancer immunotherapy.

Fe3O4 Nanoparticles That Modulate the Polarisation of Tumor-Associated Macrophages Synergize with Photothermal Therapy and Immunotherapy (PD-1/PD-L1 Inhibitors) to Enhance Anti-Tumor Therapy

Introduction

Traditional surgical resection, radiotherapy, and chemotherapy have been the treatment options for patients with head and neck squamous cell carcinoma (HNSCC) over the past few decades. Nevertheless, the five-year survival rate for patients has remained essentially unchanged, and research into treatments has been relatively stagnant. The combined application of photothermal therapy (PTT) and immunotherapy for treating HNSCC has considerable potential.

Methods

Live-dead cell staining and CCK-8 assays proved that Fe3O4 nanoparticles are biocompatible in vitro. In vitro, cellular experiments utilized flow cytometry and immunofluorescence staining to verify the effect of Fe3O4 nanoparticles on the polarisation of tumor-associated macrophages. In vivo, animal experiments were conducted to assess the inhibitory effect of Fe3O4 nanoparticles on tumor proliferation under the photothermal effect in conjunction with BMS-1. Tumour tissue sections were stained to observe the effects of apoptosis and the inhibition of tumor cell proliferation. The histological damage to animal organs was analyzed by hematoxylin and eosin (H&E) staining.

Results

The stable photothermal properties of Fe3O4 nanoparticles were validated by in vitro cellular and in vivo animal experiments. Fe3O4 photothermal action not only directly triggered immunogenic cell death (ICD) and enhanced the immunogenicity of the tumor microenvironment but also regulated the expression of tumor-associated macrophages (TAMs), up-regulating CD86 and down-regulating CD206 to inhibit tumor growth. The PD-1/PD-L1 inhibitor promoted tumor suppression, and reduced tumor recurrence and metastasis. In vivo studies demonstrated that the photothermal action exhibited a synergistic effect when combined with immunotherapy, resulting in significant suppression of primary tumors and an extension of survival.

Conclusion

In this study, we applied Fe3O4 photothermolysis in a biomedical context, combining photothermolysis with immunotherapy, exploring a novel pathway for treating HNSCC and providing a new strategy for effectively treating HNSCC.

Deep Red Light Driven Hydrogen Evolution by Heterojunction Polymer Dots for Diabetic Wound Healing

We describe small heterojunction polymer dots (Pdots) with deep-red light catalyzed H2 generation for diabetic skin wound healing. The Pdots with donor/acceptor heterojunctions showed remarkably enhanced photocatalytic activity as compared to the donor or acceptor nanoparticles alone. We encapsulate the Pdots and ascorbic acid into liposomes to form Lipo-Pdots nanoreactors, which selectively scavenge ⋅OH radicals in live cells and tissues under 650 nm light illumination. The antioxidant capacity of the heterojunction Pdots is ~10 times higher than that of the single-component Pdots described previously. Under a total light dose of 360 J/cm2, the Lipo-Pdots nanoreactors effectively scavenged ⋅OH radicals and suppressed the expression of pro-inflammatory cytokines in skin tissues, thereby accelerating the healing of skin wounds in diabetic mice. This study provides a feasible solution for safe and effective treatment of diabetic foot ulcers.