Checkpoint Nano-PROTACs for Activatable Cancer Photo-Immunotherapy

Genetically engineered nanomodulators elicit potent immunity against cancer stem cells by checkpoint blockade and hypoxia relief

Rapid development of checkpoint inhibitors has provided significant breakthroughs for cancer stem cell (CSC) therapy, while the therapeutic efficacy is restricted by hypoxia-mediated tumor immune evasion, especially hypoxia-induced CD47 overexpression in CSCs. Herein, we developed a genetically engineered CSC membrane-coated hollow manganese dioxide (hMnO2@gCMs) to elicit robust antitumor immunity by blocking CD47 and alleviating hypoxia to ultimately achieve the eradication of CSCs. The hMnO2 core effectively alleviated tumor hypoxia by inducing decomposition of tumor endogenous H2O2, thus suppressing the CSCs and reducing the expression of CD47. Cooperating with hypoxia relief-induced downregulation of CD47, the overexpressed SIRPα on gCM shell efficiently blocked the CD47-SIRPα "don't eat me" pathway, synergistically eliciting robust antitumor-mediated immune responses. In a B16F10-CSC bearing melanoma mouse model, the hMnO2@gCMs showed an enhanced therapeutic effect in eradicating CSCs and inhibiting tumor growth. Our work presents a simple, safe, and robust platform for CSC eradication and cancer immunotherapy.

New-generation advanced PROTACs as potential therapeutic agents in cancer therapy

Proteolysis-targeting chimeras (PROTACs) technology has garnered significant attention over the last 10 years, representing a burgeoning therapeutic approach with the potential to address pathogenic proteins that have historically posed challenges for traditional small-molecule inhibitors. PROTACs exploit the endogenous E3 ubiquitin ligases to facilitate degradation of the proteins of interest (POIs) through the ubiquitin-proteasome system (UPS) in a cyclic catalytic manner. Despite recent endeavors to advance the utilization of PROTACs in clinical settings, the majority of PROTACs fail to progress beyond the preclinical phase of drug development. There are multiple factors impeding the market entry of PROTACs, with the insufficiently precise degradation of favorable POIs standing out as one of the most formidable obstacles. Recently, there has been exploration of new-generation advanced PROTACs, including small-molecule PROTAC prodrugs, biomacromolecule-PROTAC conjugates, and nano-PROTACs, to improve the in vivo efficacy of PROTACs. These improved PROTACs possess the capability to mitigate undesirable physicochemical characteristics inherent in traditional PROTACs, thereby enhancing their targetability and reducing off-target side effects. The new-generation of advanced PROTACs will mark a pivotal turning point in the realm of targeted protein degradation. In this comprehensive review, we have meticulously summarized the state-of-the-art advancements achieved by these cutting-edge PROTACs, elucidated their underlying design principles, deliberated upon the prevailing challenges encountered, and provided an insightful outlook on future prospects within this burgeoning field.

Targeted pH-Activated Peptide-Based Nanomaterials for Combined Photodynamic Therapy with Immunotherapy

Photodynamic therapy (PDT) has demonstrated efficacy in eliminating local tumors, yet its effectiveness against metastasis is constrained. While immunotherapy has exhibited promise in a clinical context, its capacity to elicit significant systemic antitumor responses across diverse cancers is often limited by the insufficient activation of the host immune system. Consequently, the combination of PDT and immunotherapy has garnered considerable attention. In this study, we developed pH-responsive porphyrin-peptide nanosheets with tumor-targeting capabilities (PRGD) that were loaded with the IDO inhibitor NLG919 for a dual application involving PDT and immunotherapy (PRGD/NLG919). In vitro experiments revealed the heightened cellular uptake of PRGD/NLG919 nanosheets in tumor cells overexpressing αvβ3 integrins. The pH-responsive PRGD/NLG919 nanosheets demonstrated remarkable singlet oxygen generation and photocytotoxicity in HeLa cells in an acidic tumor microenvironment. When treating HeLa cells with PRGD/NLG919 nanosheets followed by laser irradiation, a more robust adaptive immune response occurred, leading to a substantial proliferation of CD3+CD8+ T cells and CD3+CD4+ T cells compared to control groups. Our pH-responsive targeted PRGD/NLG919 nanosheets therefore represent a promising nanosystem for combination therapy, offering effective PDT and an enhanced host immune response.

Glutathione-triggered prodrugs: Design strategies, potential applications, and perspectives

The burgeoning prodrug strategy offers a promising avenue toward improving the efficacy and specificity of cytotoxic drugs. Elevated intracellular levels of glutathione (GSH) have been regarded as a hallmark of tumor cells and characteristic feature of the tumor microenvironment. Considering the pivotal involvement of elevated GSH in the tumorigenic process, a diverse repertoire of GSH-triggered prodrugs has been developed for cancer therapy, facilitating the attenuation of deleterious side effects associated with conventional chemotherapeutic agents and/or the attainment of more efficacious therapeutic outcomes. These prodrug formulations encompass a spectrum of architectures, spanning from small molecules to polymer-based and organic-inorganic nanomaterial constructs. Although the GSH-triggered prodrugs have been gaining increasing interests, a comprehensive review of the advancements made in the field is still lacking. To fill the existing lacuna, this review undertakes a retrospective analysis of noteworthy research endeavors, based on a categorization of these molecules by their diverse recognition units (i.e., disulfides, diselenides, Michael acceptors, and sulfonamides/sulfonates). This review also focuses on explaining the distinct benefits of employing various chemical architecture strategies in the design of these prodrug agents. Furthermore, we highlight the potential for synergistic functionality by incorporating multiple-targeting conjugates, theranostic entities, and combinational treatment modalities, all of which rely on the GSH-triggering. Overall, an extensive overview of the emerging field is presented in this review, highlighting the obstacles and opportunities that lie ahead. Our overarching goal is to furnish methodological guidance for the development of more efficacious GSH-triggered prodrugs in the future. By assessing the pros and cons of current GSH-triggered prodrugs, we expect that this review will be a handful reference for prodrug design, and would provide a guidance for improving the properties of prodrugs and discovering novel trigger scaffolds for constructing GSH-triggered prodrugs.

A PROTAC Augmenter for Photo-Driven Pyroptosis in Breast Cancer

Proteolysis targeting chimera (PROTAC) has recently emerged as a promising strategy for inducing post-translational knockdown of target proteins in disease treatment. The degradation of bromodomain-containing protein 4 (BRD4), an essential nuclear protein for gene transcription, induced by PROTAC is proposed as an epigenetic approach to treat breast cancer. However, the poor membrane permeability and indiscriminate distribution of PROTAC in vivo results in low bioavailability, limiting its development and application. Herein, a nano "targeting chimera" (abbreviated as L@NBMZ) consisting of BRD4-PROTAC combined with a photosensitizer, to serve as the first augmenter for photo-driven pyroptosis in breast cancer, is developed. With excellent BRD4 degradation ability, high biosafety, and biocompatibility, L@NBMZ blocks gene transcription by degrading BRD4 through proteasomes in vivo, and surprisingly, induces the cleavage of caspase-3. This type of caspase-3 cleavage is synergistically amplified by light irradiation in the presence of photosensitizers, leading to efficient photo-driven pyroptosis. Both in vitro and in vivo outcomes demonstrate the remarkable anti-cancer efficacy of this augmenter, which significantly inhibits the lung metastasis of breast cancer in vivo. Thus, the photo-PROTAC "targeting chimera" augmenter construction strategy may pave a new way for expanding PROTAC applications within anti-cancer paradigms.

Biomimetic nanotechnology for cancer immunotherapy: State of the art and future perspective

Cancer continues to be a significant worldwide cause of mortality. This underscores the urgent need for novel strategies to complement and overcome the limitations of conventional therapies, such as imprecise targeting and drug resistance. Cancer Immunotherapy utilizes the body's immune system to target malignant cells, reducing harm to healthy tissue. Nevertheless, the efficacy of immunotherapy exhibits variation across individuals and has the potential to induce autoimmune responses. Biomimetic nanoparticles (bNPs) have transformative potential in cancer immunotherapy, promising improved accurate targeting, immune system activation, and resistance mechanisms, while also reducing the occurrence of systemic autoimmune side effects. This integration offers opportunities for personalized medicine and better therapeutic outcomes. Despite considerable potential, bNPs face barriers like insufficient targeting, restricted biological stability, and interactions within the tumor microenvironment. The resolution of these concerns is crucial in order to expedite the integration of bNPs from the research setting into clinical therapeutic uses. In addition, optimizing manufacturing processes and reducing bNP-related costs are essential for practical implementation. The present research introduces comprehensive classifications of bNPs as well as recent achievements in their application in cancer immunotherapies, emphasizing the need to address barriers for swift clinical integration.

Nanoparticles in tumor microenvironment remodeling and cancer immunotherapy

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

In vivo visualization of tumor-associated macrophages re-education by photoacoustic/fluorescence dual-modal imaging with a metal-organic frames-based caspase-1 nanoreporter

Tumor-associated macrophages (TAMs) are vital in the tumor microenvironment, contributing to immunosuppression and therapy tolerance. Despite their importance, the precise re-education of TAMs in vivo continues to present a formidable challenge. Moreover, the lack of real-time and efficient methods to comprehend the spatiotemporal kinetics of TAMs repolarization remains a significant hurdle, severely hampering the accurate assessment of treatment efficacy and prognosis. Herein, we designed a metal-organic frameworks (MOFs) based Caspase-1 nanoreporter (MCNR) that can deliver a TLR7/8 agonist to the TAMs and track time-sensitive Caspase-1 activity as a direct method to monitor the initiation of immune reprogramming. This nanosystem exhibits excellent TAMs targeting ability, enhanced tumor accumulation, and stimuli-responsive behavior. By inducing the reprogramming of TAMs, they were able to enhance T-cell infiltration in tumor tissue, resulting in inhibited tumor growth and improved survival in mice model. Moreover, MCNR also serves as an activatable photoacoustic and fluorescent dual-mode imaging agent through Caspase-1-mediated specific enzyme digestion. This feature enables non-invasive and real-time antitumor immune activation monitoring. Overall, our findings indicate that MCNR has the potential to be a valuable tool for tumor immune microenvironment remodeling and noninvasive quantitative detection and real-time monitoring of TAMs repolarization to immunotherapy in the early stage.

Supramolecular prodrug-like nanotheranostics with dynamic and activatable nature for synergistic photothermal immunotherapy of metastatic cancer

Synergistic photothermal immunotherapy has attracted widespread attention due to the mutually reinforcing therapeutic effects on primary and metastatic tumors. However, the lack of clinical approval nanomedicines for spatial, temporal, and dosage control of drug co-administration underscores the challenges facing this field. Here, a photothermal agent (Cy7-TCF) and an immune checkpoint blocker (NLG919) are conjugated via disulfide bond to construct a tumor-specific small molecule prodrug (Cy7-TCF-SS-NLG), which self-assembles into prodrug-like nano-assemblies (PNAs) that are self-delivering and self-formulating. In tumor cells, over-produced GSH cleaves disulfide bonds to release Cy7-TCF-OH, which re-assembles into nanoparticles to enhance photothermal conversion while generate reactive oxygen species (ROSs) upon laser irradiation, and then binds to endogenous albumin to activate near-infrared fluorescence, enabling multimodal imaging-guided phototherapy for primary tumor ablation and subsequent release of tumor-associated antigens (TAAs). These TAAs, in combination with the co-released NLG919, effectively activated effector T cells and suppressed Tregs, thereby boosting antitumor immunity to prevent tumor metastasis. This work provides a simple yet effective strategy that integrates the supramolecular dynamics and reversibility with stimuli-responsive covalent bonding to design a simple small molecule with synergistic multimodal imaging-guided phototherapy and immunotherapy cascades for cancer treatment with high clinical value.

Nano-PROTACs: state of the art and perspectives

PROteolysis TArgeting Chimeras (PROTACs), as a recently identified technique in the field of new drug development, provide new concepts for disease treatment and are expected to revolutionize drug discovery. With high specificity and flexibility, PROTACs serve as an innovative research tool to target and degrade disease-relevant proteins that are not currently pharmaceutically vulnerable to eliminating their functions by hijacking the ubiquitin-proteasome system. To date, PROTACs still face the challenges of low solubility, poor permeability, off-target effects, and metabolic instability. The combination of nanotechnology and PROTACs has been explored to enhance the in vivo performance of PROTACs regarding overcoming these challenging hurdles. In this review, we summarize the latest advancements in the building-block design of PROTAC prodrug nanoparticles and provide an overview of existing/potential delivery systems and loading approaches for PROTAC drugs. Furthermore, we discuss the current status and prospects of the split-and-mix approach for PROTAC drug optimization. Additionally, the advantages and translational potentials of carrier-free nano-PROTACs and their combinational therapeutic effects are highlighted. This review aims to foster a deeper understanding of this rapidly evolving field and facilitate the progress of nano-PROTACs that will continue to push the boundaries of achieving selectivity and controlled release of PROTAC drugs.

Dual-Programmable Semiconducting Polymer NanoPROTACs for Deep-Tissue Sonodynamic-Ferroptosis Activatable Immunotherapy

Proteolysis-targeting chimeras (PROTACs) can provide promising opportunities for cancer treatment, while precise regulation of their activities remains challenging to achieve effective and safe therapeutic outcomes. A semiconducting polymer nanoPROTAC (SPNFeP ) is reported that can achieve ultrasound (US) and tumor microenvironment dual-programmable PROTAC activity for deep-tissue sonodynamic-ferroptosis activatable immunotherapy. SPNFeP is formed through a nano-precipitation of a sonodynamic semiconducting polymer, a ferroptosis inducer, and a newly synthesized PROTAC molecule. The semiconducting polymers work as sonosensitizers to produce singlet oxygen (1 O2 ) via sonodynamic effect under US irradiation, and ferroptosis inducers react with intratumoral hydrogen peroxide (H2 O2 ) to generate hydroxyl radical (·OH). Such a dual-programmable reactive oxygen species (ROS) generation not only triggers ferroptosis and immunogenic cell death (ICD), but also induces on-demand activatable delivery of PROTAC molecules into tumor sites. The effectively activated nanoPROTACs degrade nicotinamide phosphoribosyl transferase (NAMPT) to suppress tumor infiltration of myeloid-derived suppressive cells (MDSCs), thus promoting antitumor immunity. In such a way, SPNFeP mediates sonodynamic-ferroptosis activatable immunotherapy for entirely inhibiting tumor growths in both subcutaneous and 2-cm tissue-covered deep tumor mouse models. This study presents a dual-programmable activatable strategy based on PROTACs for effective and precise cancer combinational therapy.

An Activatable Phototheranostic Probe for Anti-hypoxic Type I Photodynamic- and Immuno-Therapy of Cancer

Photodynamic therapy (PDT), which utilizes type I photoreactions, has great potential as an effective cancer treatment because of its hypoxia-tolerant superiority over the commonly used type II pathway. A few type I photosensitizers are exploited; however, they majorly induce cytotoxicity and possess poor tumor specificity and low-efficient theranostics. To resolve this issue, herein an aminopeptidase N (APN)-activated type I phototheranostic probe (CyA) is reported for anti-hypoxic PDT in conjunction with immunotherapy for effective cancer treatment. CyA can specifically activate near-infrared fluorescence, photoacoustic signals, and phototoxicity following APN-induced substrate cleavage and the subsequent generation of active phototheranostic molecules (such as CyBr). CyA endows specific imaging capabilities and effective phototoxicity toward tumor cells overexpressing APN under both normoxia and hypoxia. In addition, the locally activatable PDT induces systemic antitumor immune responses. More importantly, the integration of localized activated PDT and systemic immunotherapy evokes enhanced therapeutic effects with improved tumor inhibition efficiency in live mice compared with individual treatments. This study aims to present an activatable phototheranostic probe for effective hypoxia-tolerant PDT and combination therapy.

Nanomedicine Combats Drug Resistance in Lung Cancer

Lung cancer is the second most prevalent cancer and the leading cause of cancer-related death worldwide. Surgery, chemotherapy, molecular targeted therapy, immunotherapy, and radiotherapy are currently available as treatment methods. However, drug resistance is a significant factor in the failure of lung cancer treatments. Novel therapeutics have been exploited to address complicated resistance mechanisms of lung cancer and the advancement of nanomedicine is extremely promising in terms of overcoming drug resistance. Nanomedicine equipped with multifunctional and tunable physiochemical properties in alignment with tumor genetic profiles can achieve precise, safe, and effective treatment while minimizing or eradicating drug resistance in cancer. Here, this work reviews the discovered resistance mechanisms for lung cancer chemotherapy, molecular targeted therapy, immunotherapy, and radiotherapy, and outlines novel strategies for the development of nanomedicine against drug resistance. This work focuses on engineering design, customized delivery, current challenges, and clinical translation of nanomedicine in the application of resistant lung cancer.

Amino Acid-Starved Cancer Cells Utilize Macropinocytosis and Ubiquitin-Proteasome System for Nutrient Acquisition

To grow in nutrient-deprived tumor microenvironment, cancer cells often internalize and degrade extracellular proteins to refuel intracellular amino acids. However, the nutrient acquisition routes reported by previous studies are mainly restricted in autophagy-lysosomal pathway. It remains largely unknown if other protein degradation systems also contribute to the utilization of extracellular nutrients. Herein, it is demonstrated that under amino acid starvation, extracellular protein internalization through macropinocytosis and protein degradation through ubiquitin-proteasome system are activated as a nutrient supply route, sensitizing cancer cells to proteasome inhibition. By inhibiting both macropinocytosis and ubiquitin-proteasome system, an innovative approach to intensify amino acid starvation for cancer therapy is presented. To maximize therapeutic efficacy and minimize systemic side effects, a pH-responsive polymersome nanocarrier is developed to deliver therapeutic agents specifically to tumor tissues. This nanoparticle system provides an approach to exacerbate amino acid starvation for cancer therapy, which represents a promising strategy for cancer treatment.

Recent Advances in Optically Controlled PROTAC

Proteolysis-targeting chimera (PROTAC) technology is a groundbreaking therapeutic approach with significant clinical potential for degrading disease-inducing proteins within targeted cells. However, challenges related to insufficient target selectivity raise concerns about PROTAC toxicity toward normal cells. To address this issue, researchers are modifying PROTACs using various approaches to enhance their target specificity. This review highlights innovative optically controlled PROTACs as anti-cancer therapies currently used in clinical practice and explores the challenges associated with their efficacy and safety. The development of optically controlled PROTACs holds the potential to significantly expand the clinical applicability of PROTAC-based technology within the realm of drug discovery.

High-Precision Single-Cell microRNA Therapy by a Functional Nanopipette with Sensitive Photoelectrochemical Feedback

This work proposes the concept of single-cell microRNA (miR) therapy and proof-of-concept by engineering a nanopipette for high-precision miR-21-targeted therapy in a single HeLa cell with sensitive photoelectrochemical (PEC) feedback. Targeting the representative oncogenic miR-21, the as-functionalized nanopipette permits direct intracellular drug administration with precisely controllable dosages, and the corresponding therapeutic effects can be sensitively transduced by a PEC sensing interface that selectively responds to the indicator level of cytosolic caspase-3. The experimental results reveal that injection of ca. 4.4 × 10-20  mol miR-21 inhibitor, i.e., 26488 copies, can cause the obvious therapeutic action in the targeted cell. This work features a solution to obtain the accurate knowledge of how a certain miR-drug with specific dosages treats the cells and thus provides an insight into futuristic high-precision clinical miR therapy using personalized medicine, provided that the prerequisite single-cell experiments are courses of personalized customization.

Three Strategies in Engineering Nanomedicines for Tumor Microenvironment-Enabled Phototherapy

Canonical phototherapeutics have several limitations, including a lack of tumor selectivity, nondiscriminatory phototoxicity, and tumor hypoxia aggravation. The tumor microenvironment (TME) is characterized by hypoxia, acidic pH, and high levels of H2 O2 , GSH, and proteases. To overcome the shortcomings of canonical phototherapy and achieve optimal theranostic effects with minimal side effects, unique TME characteristics are employed in the development of phototherapeutic nanomedicines. In this review, the effectiveness of three strategies for developing advanced phototherapeutics based on various TME characteristics is examined. The first strategy involves targeted delivery of phototherapeutics to tumors with the assistance of TME-induced nanoparticle disassembly or surface modification. The second strategy involves near-infrared absorption increase-induced phototherapy activation triggered by TME factors. The third strategy involves enhancing therapeutic efficacy by ameliorating TME. The functionalities, working principles, and significance of the three strategies for various applications are highlighted. Finally, possible challenges and future perspectives for further development are discussed.

Self-Assembled Nano-PROTAC Enables Near-Infrared Photodynamic Proteolysis for Cancer Therapy

Confining the protein degradation activity of proteolysis-targeting chimera (PROTAC) to cancer lesions ensures precision treatment. However, it still remains challenging to precisely control PROTAC function in tumor regions in vivo. We herein describe a near-infrared (NIR) photoactivatable nano-PROTAC (NAP) for remote-controllable proteolysis in tumor-bearing mice. NAP is formed by molecular self-assembly from an amphiphilic conjugate of PROTAC linked with an NIR photosensitizer through a singlet oxygen (1O2)-cleavable linker. The activity of PROTAC is initially silenced but can be remotely switched on upon NIR photoirradiation to generate 1O2 by the photosensitizer. We demonstrated that NAP enabled tumor-specific degradation of bromodomain-containing protein 4 (BRD4) in an NIR light-instructed manner. This in combination with photodynamic therapy (PDT) elicited an effective suppression of tumor growth. This work thus presents a novel approach for spatiotemporal control over targeted protein degradation by PROTAC.

Impairing Tumor Metabolic Plasticity via a Stable Metal-Phenolic-Based Polymeric Nanomedicine to Suppress Colorectal Cancer

Targeting metabolic vulnerability of tumor cells is a promising anticancer strategy. However, the therapeutic efficacy of existing metabolism-regulating agents is often compromised due to tolerance resulting from tumor metabolic plasticity, as well as their poor bioavailability and tumor-targetability. Inspired by the inhibitive effect of N-ethylmaleimide on the mitochondrial function, a dendronized-polymer-functionalized metal-phenolic nanomedicine (pOEG-b-D-SH@NP) encapsulating maleimide-modified doxorubicin (Mal-DOX) is developed to enable improvement in the overall delivery efficiency and inhibition of the tumor metabolism via multiple pathways. It is observed that Mal-DOX and its derived nanomedicine induces energy depletion of CT26 colorectal cancer cells more efficiently than doxorubicin, and shifts the balance of programmed cell death from apoptosis toward necroptosis. Notably, pOEG-b-D-SH@NP simultaneously inhibits cellular oxidative phosphorylation and glycolysis, thus potently suppressing cancer growth and peritoneal intestinal metastasis in mouse models. Overall, the study provides a promising dendronized-polymer-derived nanoplatform for the treatment of cancers through impairing metabolic plasticity.

Magnetic-Manipulated NK Cell Proliferation and Activation Enhance Immunotherapy of Orthotopic Liver Cancer

The immunotherapy of deep solid tumors in the human body, such as liver cancer, still faces great challenges, especially the inactivation and insufficient infiltration of immune cells in solid tumor microenvironment. Natural killer (NK) cells are gaining ever-increasing attention owing to their unique features and are expected to play an important role in the liver cancer immunotherapy. However, NK cells are severely insufficient and inactivated in solid liver tumor due to the highly immunosuppressive intratumor microenvironment, resulting in poor clinical therapeutic efficacy. Herein, we propose a mild magnetocaloric regulation approach using a magnetogenetic nanoplatform MNPs@PEI-FA/pDNA (MPFD), which is synthesized by loading a heat-inducible plasmid DNA (HSP70-IL-2-EGFP) on polyethyleneimine (PEI)- and folic acid (FA)-modified ZnCoFe₂O₄@ZnMnFe₂O₄ magnetic nanoparticles (MNPs) to promote the proliferation and activation of tumor-infiltrating NK cells under magnetic manipulation without the limitation of penetration depth for orthotopic liver cancer immunotherapy. The magnetothermally responsive MPFD serves as a magnetism-heat nanotransducer to induce the gene transcription of IL-2 cytokine in orthotopic liver tumor for NK cell proliferation and activation. Both in vitro and in vivo results demonstrate that the remote mild magnetocaloric regulation (∼40 °C) by MPFD initiates the HSP70 promoter to trigger the overexpression of IL-2 cytokine for subsequent secretion, leading to in situ expansion and activation of tumor-infiltrating NK cells through the IL-2/IL-2 receptor (IL-2R) pathways and the resulting prominent tumor inhibition. This work not only evidences the great potential of magnetogenetic nanoplatform but also reveals the underlying proliferation and activation mechanism of NK cells in liver cancer treatment by magnetogenetic nanoplatform.

Engineering MMP-2 Activated Nanoparticles Carrying B7-H3 Bispecific Antibodies for Ferroptosis-Enhanced Glioblastoma Immunotherapy

Administration of bispecific antibodies (biAbs) in tumor therapy is limited by their short half-life and off-target toxicity. Optimized strategies or targets are needed to overcome these barriers. B7-H3 (CD276), a member of the B7 superfamily, is associated with poor survival in glioblastoma (GBM) patients. Moreover, a dimer of EGCG (dEGCG) synthesized in this work enhanced the IFN-γ-induced ferroptosis of tumor cells in vitro and in vivo. Herein, we prepared recombinant anti-B7-H3×CD3 biAbs and constructed MMP-2-sensitive S-biAb/dEGCG@NPs to offer a combination treatment strategy for efficient and systemic GBM elimination. Given their GBM targeted delivery and tumor microenvironment responsiveness, S-biAb/dEGCG@NPs displayed enhanced intracranial accumulation, 4.1-, 9.5-, and 12.3-fold higher than that of biAb/dEGCG@NPs, biAb/dEGCG complexes, and free biAbs, respectively. Furthermore, 50% of GBM-bearing mice in the S-biAb/dEGCG@NP group survived longer than 56 days. Overall, S-biAb/dEGCG@NPs can induce GBM elimination by boosting the ferroptosis effect and enhancing immune checkpoint blockade (ICB) immunotherapy and may be successful antibody nanocarriers for enhanced cancer therapy.

Targeted Protein Degradation Technology and Nanomedicine: Powerful Allies against Cancer

Targeted protein degradation (TPD) is an emerging therapeutic strategy with the potential of targeting undruggable pathogenic proteins. After the first proof-of-concept proteolysis-targeting chimeric (PROTAC) molecule was reported, the TPD field has entered a new era. In addition to PROTAC, numerous novel TPD strategies have emerged to expand the degradation landscape. However, their physicochemical properties and uncontrolled off-target side effects have limited their therapeutic efficacy, raising concerns regarding TPD delivery system. The combination of TPD and nanotechnology offers great promise in improving safety and therapeutic efficacy. This review provides an overview of novel TPD technologies, discusses their clinical applications, and highlights the trends and perspectives in TPD nanomedicine.

The E3 ubiquitin ligases regulate PD-1/PD-L1 protein levels in tumor microenvironment to improve immunotherapy

The tumor microenvironment (TME) is the tumor surrounding environment, which is critical for tumor development and progression. TME is also involved in clinical intervention and treatment outcomes. Modulation of TME is useful for improving therapy strategies. PD-L1 protein on tumor cells interacts with PD-1 protein on T cells, contributing to T cell dysfunction and exhaustion, blockage of the immune response. Evidence has demonstrated that the expression of PD-1/PD-L1 is associated with clinical response to anti-PD-1/PD-L1 therapy in cancer patients. It is important to discuss the regulatory machinery how PD-1/PD-L1 protein is finely regulated in tumor cells. In recent years, studies have demonstrated that PD-1/PD-L1 expression was governed by various E3 ubiquitin ligases in TME, contributing to resistance of anti-PD-1/PD-L1 therapy in human cancers. In this review, we will discuss the role and molecular mechanisms of E3 ligases-mediated regulation of PD-1 and PD-L1 in TME. Moreover, we will describe how E3 ligases-involved PD-1/PD-L1 regulation alters anti-PD-1/PD-L1 efficacy. Altogether, targeting E3 ubiquitin ligases to control the PD-1/PD-L1 protein levels could be a potential strategy to potentiate immunotherapeutic effects in cancer patients.