Ternary Regulation of Tumor Microenvironment by Heparanase-Sensitive Micelle-Loaded Monocytes Improves Chemo-Immunotherapy of Metastatic Breast Cancer

Tumor immunotherapy approaches such as programmed cell death-1/programmed cell death-ligand 1 (PD-1/PD-L1) checkpoint blockade and indoleamine 2,3-dioxygenase (IDO) inhibition are proven to promote immune response against tumors. Unfortunately, their positive response rates are unsatisfactory due to complicated immunosuppressive mechanisms in the tumor microenvironment, which can probably be rescued by integrating multiple immunoregulators and chemotherapeutic agents together. To improve the combination therapy of metastatic breast cancer, a ternary heparanase (Hpa)-sensitive micelle-loaded monocyte delivery system, termed as HDNH@MC, is designed, exploiting the capacity of Ly6C^hi monocytes to be recruited to tumor sites and the overexpression of Hpa in tumors. The prodrugs of the chemotherapeutic agent docetaxel and IDO inhibitor NLG919 are synthesized by conjugating them on the substrate of Hpa, heparan sulfate. Then the PD-1/PD-L1 inhibitor HY19991-encapsulating prodrug micelle@Ly6C^hi monocyte system is prepared. HNDH@MC elevates drug concentrations and relieves immunosuppression in tumors of 4T1 breast carcinomas mice model, thus enhancing the infiltration and activity of CD8⁺ T cells and presenting significant anti-cancer effect. The lung metastasis is suppressed and the survival of mice is prolonged. HNDH@MC will be a promising option for treating metastatic breast cancer by synergy of tumor-targeting chemotherapy and immunotherapy.     

Mitochondria-Targeted Photodynamic and Mild-Temperature Photothermal Therapy for Realizing Enhanced Immunogenic Cancer Cell Death via Mitochondrial Stress

Induction of immunogenic cell death (ICD) represents a robust therapeutic strategy for cancer treatment. However, only a few ICD inducers are currently available and many of them take effect based on traditional endoplasmic reticulum (ER) stress rather than mitochondrial stress. Besides, mitochondrion is closely related to ER and drug delivery via mitochondrial targeting usually shows a higher efficiency and cytotoxicity than that via ER targeting, which inspires to explore the ICD effect of cancer cells through mitochondrial stress. Herein, a mito-missile that can realize not only mitochondria-targeted photodynamic therapy (PDT)/mild-temperature photothermal therapy (MTPTT) but also ICD-induced cancer immunotherapy is constructed. The mito-missile (termed DIH) is prepared by coating dc-IR825 (a mitochondrion-targeting cyanine dye)-loaded polyamidoamine dendrimer with hyaluronic acid. dc-IR825 can precisely target mitochondria and produce reactive oxygen species (ROS) and mild heat upon near-infrared (NIR) light irradiation, inducing mitochondrial damage and mitochondrial stress-caused enhanced ICD. By combining PDT, MTPTT, and ICD-induced immunotherapy, the DIH mito-missile can efficiently inhibit tumor growth and even eradicate tumors. This study develops a dendrimer-based nanoplatform for realizing mitochondrion-acting PDT/MTPTT as well as mitochondrial stress-induced potentiated ICD, which may provide a guideline for designing effective ICD inducers in the future.     

PtCu Nanosonosensitizers with Inflammatory Microenvironment Regulation for Enhanced Sonodynamic Bacterial Elimination and Tissue Repair

Sonodynamic therapy (SDT) is considered a reliable replacement therapy to overcome the resistance to antibiotics and the limited tissue penetration of traditional photo-induced therapy. Herein, ultrasmall platinum-copper alloy nanoparticles (PtCu NPs) modified with poly (maleic anhydridealt-1-octadecene)-polyethylene glycol (C₁₈PMH-PEG) with high sonodynamic activity, strong catalytic ability, and good glutathione (GSH) depletion performance are synthesized for highly efficient bacterial elimination. PtCu NPs obtained through a thermal decomposition approach can generate high toxic singlet oxygen (¹O₂) under ultrasound (US) irradiation, showing good sonodynamic performance. Meanwhile, the partial oxygenation formed on the surface of PtCu NPs endows them with good Fenton-like catalytic performance and superior GSH-depleting ability, thus enhancing reactive oxygen species (ROS) generation. In vitro experiments confirm that the synthesized PtCu- NPs can not only efficiently kill both gram-positive and gram-negative bacteria but also eliminate staphylococcus aureus (S. aureus) infection through ROS generation and then accelerate wound healing in the S. aureus-infected wound model. Meanwhile, the copper ions released from PtCu NPs can promote cell migration and angiogenesis through the up-regulation of hypoxia inducible factor (HIF-1α) and platelet endothelial cell adhesion molecule (CD31). Finally, the S. aureus-induced deep-seated osteomyelitis infection and bone destruction were successfully inhibited by the PtCu-mediated combination therapy. Our work highlights a novel SDT strategy for enhanced sonodynamic bacteria elimination and tissue repair.     

Engineered Oxygen Factories Synergize with STING Agonist to Remodel Tumor Microenvironment for Cancer Immunotherapy

Immunotherapy is a revolutionary achievement in cancer treatment. However, inadequate immune cells infiltration in tumor microenvironment (TME) always leads to treatment failure. Moreover, hypoxic TME hampers normal functions of immune cells. Here, it is found that hypoxia suppresses the STING signaling and immune cells activation in the work. Remodeling tumor immune microenvironment and relieving hypoxia are thus essential for enhancing immunotherapy efficiency. Herein, a spirulina platensis (SP)-based magnetic biohybrid system is constructed as an oxygen factory and loaded with stimulator of interferon genes (STING) agonist ADU-S100 (ADU@Fe-SP) for tumor immunotherapy. Magnet-guided biohybrid SP can actively target tumor tissues and produce oxygen in situ through photosynthesis, which reverses the hypoxic TME and facilitates the function of immune cells. Besides, the targeted delivery of ADU-S100 can activate the STING/TBK1/IRF3 signaling and boost cytokines production in tumor and innate immune cells. The ADU@Fe-SP system thus induces efficient immune cells infiltration in TME, which efficiently inhibits tumor progression and significantly enhances anti-PD-1 therapy efficiency in SCC VII-bearing tumor xenograft. ADU@Fe-SP exerts antitumor effect in a STING-dependent manner by in vivo STING-knockout mice model. The efficiency of this immunotherapy strategy is also demonstrated in patient-derived xenograft model originating from oral cancer, showing great clinical potential.     

Engineering a Therapy‐Induced “Immunogenic Cancer Cell Death” Amplifier to Boost Systemic Tumor Elimination

Immunogenic cancer cell death (ICD) is drawing worldwide attention as it allows dying cancer cells to regulate the host's anti‐tumor immune system and awaken immunosurveillance. Thus, effectively activating therapy‐induced ICD is of great clinical significance to raise systemic anti‐tumor immunity and eradicate post‐treatment/abscopal cancer tissues. Enhanced cytotoxic reactive oxygen species (ROS) generation in cancer therapy has been positively correlated to ICD induction, which inspires design of a therapy‐induced ICD amplifier. The nanohybrid amplifier (FeOOH@STA/Cu‐LDH) is devised based on Cu‐containing layered double hydroxide (Cu‐LDH), incorporating ROS inducer (FeOOH nanodots), ROS generation booster (Cu‐LDH for photothermal therapy), and heat shock protein inhibitor (STA). Treating 4T1 tumor cells with this amplifier translocates calreticulins (CRT, one of main ICD signals) on the surface of dying cancer cells, which achieves the maximum at fever‐type temperature (40–42 °C). To demonstrate immunotherapeutic efficacy of this nanohybrid, 4T1 tumor‐bearing mouse model is established with primary and abscopal tumors. Significantly, only one treatment with the ICD amplifier eradicates the primary tumor and inhibits the abscopal tumor growth upon fever‐type heating and induces more cytotoxic T lymphocytes in abscopal tumors and spleens after treatment for 1 week. This research thus provides a new insight into nanomaterial‐mediated tumor immunotherapy.     

Multiplex SERS Detection of Metabolic Alterations in Tumor Extracellular Media

The composition and intercellular interactions of tumor cells in the tissues dictate the biochemical and metabolic properties of the tumor microenvironment. The metabolic rewiring has a profound impact on the properties of the microenvironment, to an extent that monitoring such perturbations could harbor diagnostic and therapeutic relevance. A growing interest in these phenomena has inspired the development of novel technologies with sufficient sensitivity and resolution to monitor metabolic alterations in the tumor microenvironment. In this context, surface‐enhanced Raman scattering (SERS) can be used for the label‐free detection and imaging of diverse molecules of interest among extracellular components. Herein, the application of nanostructured plasmonic substrates comprising Au nanoparticles, self‐assembled as ordered superlattices, to the precise SERS detection of selected tumor metabolites, is presented. The potential of this technology is first demonstrated through the analysis of kynurenine, a secreted immunomodulatory derivative of the tumor metabolism and the related molecules tryptophan and purine derivatives. SERS facilitates the unambiguous identification of trace metabolites and allows the multiplex detection of their characteristic fingerprints under different conditions. Finally, the effective plasmonic SERS substrate is combined with a hydrogel‐based three‐dimensional cancer model, which recreates the tumor microenvironment, for the real‐time imaging of metabolite alterations and cytotoxic effects on tumor cells.     

Design of Calixarene-Based ICD Inducer for Efficient Cancer Immunotherapy

Immunogenic cell death (ICD), which in situ generates cancer vaccines and elicits protective cognate anticancer immunity, has brought brightness to cancer immunotherapy. However, poor immunogenicity and low response rate of current ICD-inducing strategies restrict the development and clinical application of ICD-based immunotherapy. Herein, a novel calixarene, quaternary ammonium-modified azocalix[4]arene (CA-3) that drive bona fide ICD with high efficiency, is presented. In addition, the unique macrocyclic structure offers CA-3 with great potential to bind with anticancer drugs via host–guest interactions. With these two functions in one molecule, CA-3 effectively cooperates with various chemotherapeutics to improve their anticancer performance by activating ICD-associated anti-tumor immunity. These unique characteristics make CA-3, a general platform for improving the prognosis of many chemotherapies commonly used in clinical practice. Furthermore, the structure-activity relationship established in this study also provides insights for the design and synthesis of more efficient calixarene-based ICD inducers.     

Persistent Regulation of Tumor Microenvironment via Circulating Catalysis of MnFe2O4@Metal–Organic Frameworks for Enhanced Photodynamic Therapy

Reactive oxygen species (ROS)‐based cancer therapy, such as photodynamic therapy (PDT), is subject to the hypoxia and overexpressed glutathione (GSH) found in the tumor microenvironment (TME). Herein, a novel strategy is reported to continuously and simultaneously regulate tumor hypoxia and reducibility in order to achieve the desired therapeutic effect. To accomplish this, a biocompatible nanoplatform (MnFe₂O₄@metal–organic framework (MOF)) is developed by integrating a coating of porphyrin‐based MOF as the photosensitizer and manganese ferrite nanoparticle (MnFe₂O₄) as the nanoenzyme. The synthetic MnFe₂O₄@MOF nanoplatform exhibits both catalase‐like and glutathione peroxidase‐like activities. Once internalized in the tumor, the nanoplatform can continuously catalyze H₂O₂ to produce O₂ to overcome the tumor hypoxia by cyclic Fenton reaction. Meanwhile, combined with the Fenton reaction, MnFe₂O₄@MOF is able to persistently consume GSH in the presence of H₂O₂, which decreases the depletion of ROS upon laser irradiation during PDT and achieves better therapeutic efficacy in vitro and in vivo. Moreover, the nanoplatform integrates a treatment modality with magnetic resonance imaging, along with persistent regulation of TME, to promote more precise and effective treatment for future clinical application.     

Transformable Nanoparticle‐Enabled Synergistic Elicitation and Promotion of Immunogenic Cell Death for Triple‐Negative Breast Cancer Immunotherapy

Although cisplatin‐based neoadjuvant chemotherapy is an efficient therapy approach for triple‐negative breast cancer (TNBC), it has dismal prognosis and modestly improved survival benefit. Here, a synergistic immunotherapy of TNBC premised on the elicitation and promotion of immunogenic cell death (ICD) response, through a transformable nanoparticle‐enabled approach for contemporaneous delivery of cisplatin, adjudin, and WKYMVm is reported. The nanoparticles can sequentially respond to matrix metalloproteinases‐2, pH, and glutathione to achieve structural transformation with the advantages of optimal size change, efficient drug delivery, and well‐controlled release. Cisplatin and adjudin can synergistically amplify reactive oxygen species (ROS) cascade and eventually increase the formation of hydrogen peroxide and downstream highly toxic ROS like ?OH, which can elicit ICD response by mechanisms of endoplasmic reticulum stress, apoptotic cell death, and autophagy. WKYMVm can further promote anti‐TNBC immunity by activation of formyl peptide receptor 1 to build stable interactions between dendritic cells and dying cancer cells. Thus, the nanoparticles achieve significant primary tumor regression and pulmonary metastasis inhibition as well as a remarkable survival benefit, with boosting of the innate and adaptive anti‐TNBC immunity.     

High-Throughput Magnetic Actuation Platform for Evaluating the Effect of Mechanical Force on 3D Tumor Microenvironment

Accurately replicating and analyzing cellular responses to mechanical cues is vital for exploring metastatic disease progression. However, many of the existing in vitro platforms for applying mechanical stimulation seed cells on synthetic substrates. To better recapitulate physiological conditions, a novel actuating platform is developed with the ability to apply tensile strain on cells at various amplitudes and frequencies in a high-throughput multi-well culture plate using a physiologically relevant substrate. Suspending fibrillar fibronectin across the body of the magnetic actuator provides a matrix representative of early metastasis for 3D cell culture that is not reliant on a synthetic substrate. This platform enables the culturing and analysis of various cell types in an environment that mimics the dynamic stretching of lung tissue during normal respiration. Metabolic activity, YAP activation, and morphology of breast cancer cells are analyzed within one week of cyclic stretching or static culture. Further, matrix degradation is significantly reduced in breast cancer cell lines with metastatic potential after actuation. These new findings demonstrate a clear suppressive cellular response due to cyclic stretching that has implications for a mechanical role in the dormancy and reactivation of disseminated breast cancer cells to macrometastases.     

A Chemoimmunotherapy Nanogel Enables Efficient Delivery of Interleukin-2 and Induction of Immunogenic Cell Death for Effective Cancer Therapy

Interleukin-2 (IL-2) is one of the first FDA-approved immunotherapeutics, but its use is limited by toxicity and low efficacy. In addition, all immunotherapies are limited by the immunosuppressive and desmoplastic microenvironment of “immunologically cold” tumors, such as pancreatic ductal adenocarcinoma (PDAC) or hepatocellular carcinoma (HCC) with advanced liver fibrosis. Here, a new chemoimmunotherapy nanogel (IL2-Pt@Nanogel) for dual delivery of IL-2 and the type II immunogenic cell death inducer Pt-NHC that reduces the immunosuppressive phenotype of tumor-associated macrophages and diminishes regulatory T cell infiltration by inducing the production of type I interferon (IFN) by cancer cells is reported. Combining the angiotensin II receptor blocker losartan with IL2-Pt@Nanogel treatment reduces desmoplasia and reprogrammes the microenvironment of PDAC and HCC toward an immunostimulatory one. These effects result in potent anti-tumor efficacy in models of primary and metastatic PDAC and HCC with underlying liver fibrosis. This study presents a strategy for IL-2-based chemoimmunotherapy with the potential for clinical translation to treat solid tumors.     

Transcytosis Mediated Deep Tumor Penetration for Enhanced Chemotherapy and Immune Activation of Pancreatic Cancer

The hyperproliferative tumor stroma of pancreatic ductal adenocarcinoma (PDAC) severely limits drug permeation and constructs an immunosuppressive microenvironment, causing resistance to chemotherapy and immunotherapy. Traditional nanomedicine mainly focuses on manipulating nanoparticles’ particle size or electrical characteristics to penetrate deep PDAC through the paracellular pathway, but the transcellular pathway is often ignored. Therefore, a versatile drug-polymer conjugate PODEA-Gem-HMI is prepared and assembled into nanoparticles for the codelivery of chemotherapy drug gemcitabine and focal adhesion kinase (FAK) inhibitor defactinib. While sensing the mild acidity in the tumor microenvironment, the nanoparticle will disintegrate and release defactinib to modulate the tumor stroma. The PODEA block of the conjugate can bind with cell membranes reversibly and trigger adsorption-mediated transcytosis (AMT) for promoted tumor penetration and cellular uptake. The internalized conjugates will release gemcitabine responding to the overexpressed glutathione (GSH) for enhanced chemotherapy, and PHMI can condensate the STING monomers for prolonged spontaneous immune stimulation.     

Engineering Oncolytic Adenoviruses with VSVG-Decorated Tumor Cell Membranes for Synergistically Enhanced Antitumor Therapy

Oncolytic viruses hold great promise for cancer treatment but their practical applications are seriously impaired by a series of limitations. Herein, an engineered oncolytic adenovirus (OA) is constructed that can boost both the direct oncolysis and antitumor immune response of OA attributed to the increased tumor targeting and low-pH responsive fusogenic activity. The tumor cell membranes are decorated with vesicular stomatitis virus glycoprotein (VSVG) via vesicular stomatitis virus (VSV) infection and then used to mask OA (V-M@OA). After systemic administration, the engineered OA can target homologous tumors owing to the homing ability of tumor membranes. Then the unique low-pH responsive fusogenic activity of VSVG significantly enhances the replication of OA by promoting the whole virus infection process, resulting in remarkable virus-mediated tumoricidal effects and thus abundant in situ released tumor-associated antigens (TAAs). Meanwhile, VSVG on V-M@OA augments the adjuvanticity of OA and thus significantly enhancing the antitumor immune response. The synergism of virus-mediated killing and immune effects leads to significant tumor inhibition with no obvious side effects.     

Programmed Multiresponsive Vesicles for Enhanced Tumor Penetration and Combination Therapy of Triple‐Negative Breast Cancer

Nanomedicine is a promising approach for combination chemotherapy of triple‐negative breast cancer (TNBC). However, the therapeutic efficacy of nanoparticulate drugs is suppressed by a series of biological barriers. The authors herein present a programmed stimuli‐responsive liposomal vesicle to overcome the sequential barriers for enhanced TNBC therapy. The intelligent vesicles are engineered by integrating an enzyme‐cleavable polyethylene glycol (PEG) corona, a light‐responsive photosensitizer pheophorbide a (PPa), and a temperature‐sensitive liposome (TSL) into a single nanoplatform. The resultant enzyme, light, and temperature multisensitive liposome (ELTSL) is sequentially coloaded with a lipophilic oxaliplatin prodrug of hexadecyl‐oxaliplatin carboxylic acid (HOC) and hydrophilic doxorubicin hydrochloride (DOX). Dual drug‐loaded ELTSL displays enhanced tumor penetration and increased cellular uptake upon matrix metalloproteinase 2 mediated cleavage of the PEG corona. Under NIR laser irradiation, PPa induces mild hyperthermia effect to trigger ultrafast drug release in the tumor cells. In combination with PPa‐mediated photodynamic therapy, HOC and DOX coloaded ELTSL show significantly improved antitumor efficacy than monotherapy. Given the clinically translatable potential of the liposomal vesicles, ELTSL might represent a promising nanoplatform for combination TNBC therapy.     

Morphology Controlled Poly(aminophenylboronic acid) Nanostructures as Smart Substrates for Enhanced Capture and Release of Circulating Tumor Cells

A strategy is proposed to achieve an enhanced capture efficiency of and low damage to human leukemic lymphoblasts (CCRF‐CEM) by the synergistic effect of topographical interactions and phenylboronic acid functional groups on nanostructures. To realize this purpose, a simple and template free method to synthesize boronic acid derivative polyaniline bioinspired nanostructures with controlled morphology is established. Different nanostructured morphologies such as nanotexture, nanofibers, nanoparticles, microsphere, and 3D porous network have been prepared by controlling the nucleation and growth rate for polymerization. The phenylboronic acid functional groups on the surface of the nanostructures during poly­merization are used as artificial lectins to reversibly capture and release circulating tumor cells (CTCs) with little damage to the cells. The method presented here is simple, rapid, and highly efficient for CTC capture and release with low cost in materials and instruments.     

Long Circulation Red‐Blood‐Cell‐Mimetic Nanoparticles with Peptide‐Enhanced Tumor Penetration for Simultaneously Inhibiting Growth and Lung Metastasis of Breast Cancer

Limited blood circulation and poor tumor penetration are two main obstacles hampering the clinical translation of conventional nanosized drug delivery systems (NDDS). Here, red‐blood‐cell (RBC)‐mimetic nanoparticles (NPs) with long circulation and peptide‐enhanced tumor penetration for treating metastatic breast cancer are reported. The RBC‐mimetic NPs are composed of a paclitaxel (PTX)‐loaded polymeric core and a hydrophilic RBC vesicle shell. The RBC‐mimetic NPs display dramatically elongated blood circulation with an elimination half time of 32.8 h, 5.8‐fold higher than that of the parental polymeric NPs (i.e., 5.6 h). Moreover, the experimental results demonstrate that the tumor penetration ability of the RBC‐mimetic NPs can be significantly improved by coadministrating with a tumor‐penetrating peptide iRGD. Antitumor studies using a metastatic 4T1 breast tumor model show that RBC‐mimetic NPs in combination with iRGD significantly inhibit over 90% of the tumor growth and suppress 95% of the lung metastasis, much more efficient than PTX‐loaded polymer NP alone or the combination of polymer NPs and iRGD. The results reveal the importance of both long circulation and tumor penetration of nanosized drugs for efficient cancer therapy, which can provide a new insight for NDDS design.     

Tumor Microenvironment‐Responsive Dual Drug Dimer‐Loaded PEGylated Bilirubin Nanoparticles for Improved Drug Delivery and Enhanced Immune‐Chemotherapy of Breast Cancer

The application of combinational therapy makes up for the limitation of monotherapy and achieves superior treatment against cancer. However, the combinational therapy remains restricted by the poor tumor‐specific delivery and the abscopal effect. Herein, reactive oxygen species (ROS)‐responsive PEGylated bilirubin nanoparticles (BRNPs) are developed to encapsulate two glutathione‐activatable drugs, including dimer‐7‐ethyl‐10‐hydroxycamptothecin (d‐SN38) and dimer‐lonidamine (d‐LND). Dimerization of the drugs significantly increases the drug loading capacity and the encapsulation efficiency of nanoparticles. With the assistance of iRGD peptide (cRGDKGPDC), the cellular uptake of BRNPs is more than double when compared with the control. In response to high levels of intracellular ROS, d‐SN38 and d‐LND are rapidly released from nanoparticles (SL@BRNPs). Furthermore, the pharmacodynamic experiments verify combining SL@BRNPs with anti‐PD‐L1 antibody greatly inhibits the primary tumor of breast cancer, improves CD8+ T cells levels, and CD8+ T cells/Tregs ratios in the tumor. Additionally, it shows high immune memory effect and can prevent the growth of lung metastasis. Taken together, the strategy pioneers a new way for the rational design of nanoassemblies through the combination of activatable drug dimers and stimuli‐responsive drug release, and a successful application of novel drug delivery systems in combination with the immune checkpoint blockade antibody.     

Hyaluronidase with pH‐responsive Dextran Modification as an Adjuvant Nanomedicine for Enhanced Photodynamic‐Immunotherapy of Cancer

The condensed tumor extracellular matrix (ECM) consisting of cross‐linked hyaluronic acid (HA) is one of key factors that results in the aberrant tumor microenvironment (TME) and the resistance to various types of therapies. Herein, hyaluronidase (HAase) is modified by a biocompatible polymer, dextran (DEX), via a pH‐responsive traceless linker. The formulated DEX‐HAase nanoparticles show enhanced enzyme stability, reduced immunogenicity, and prolonged blood half‐life after intravenous injection. With efficient tumor passive accumulation, DEX‐HAase within the acidic TME would be dissociated to release native HAase, which afterward triggers the breakdown of HA to loosen the ECM structure, subsequently leading to enhanced penetration of oxygen and other therapeutic agents. The largely relieved tumor hypoxia would promote the therapeutic effect of nanoparticle‐based photodynamic therapy (PDT), accompanied by the reverse of the immunosuppressive TME to boost cancer immunotherapy. Interestingly, the therapeutic responses achieved by the combination of PDT and anti‐programmed death‐ligand 1 (anti‐PD‐L1) checkpoint blockade therapy could be significantly enhanced by pretreatment with DEX‐HAase. In addition to destructing tumors with direct light exposure, a robust abscopal effect is achieved after such treatment, which is promising for tumor metastasis inhibition. The work presents a new type of adjuvant nanomedicine to assist photodynamic‐immunotherapy of cancer, by effective modulation of TME.