Light-inducible nanodrug-mediated photodynamic and anti-apoptotic synergy for enhanced immunotherapy in triple-negative breast cancer.

Triple negative breast cancer (TNBC) exhibits limited responsiveness to immunotherapy owing to its immunosuppressive tumor microenvironment (TME). Here, a reactive oxygen species (ROS)-labile nanodrug encapsulating the photosensitizer Ce6 and Bcl-2 inhibitor ABT-737 was developed to provoke a robust immune response via the synergistic effect of photodynamic therapy (PDT) and the reversal of apoptosis resistance. Upon exposure to first-wave near-infrared laser irradiation, the generated ROS triggers PEG cleavage, facilitating the accumulation of the nanodrug at tumor region and endocytosis by tumor cells. Further irradiation leads to the substantial generation of cytotoxic ROS, initiating an immunogenic cell death (ICD) cascade, which prompts the maturation of dendritic cells (DCs) as well as the infiltration of T cells into the tumor site. Meanwhile, Bcl-2 inhibition counteracts apoptosis resistance, thereby amplifying PDT-induced ICD and bolstering antitumor immunity. As a result, the ROS-sensitive nanodrug demonstrates a potent inhibitory effect on tumor growth.

Anchoring Microbubbles on Cerebrovascular Endothelium as a New Strategy Enabling Low-Energy Ultrasound-Assisted Delivery of Varisized Agents Across Blood-Brain Barrier.

The protective blood-brain barrier (BBB) prevents most therapeutic agents from entering the brain. Currently, focused ultrasound (FUS) is mostly employed to create microbubbles that induce a cavitation effect to open the BBB. However, microbubbles pass quickly through brain microvessels, substantially limiting the cavitation effect. Here, we constructed a novel perfluoropropane-loaded microbubble, termed ApoER-Pep-MB, which possessed a siloxane bonds-crosslinked surface to increase the microbubble stability against turbulence in blood circulation and was decorated with binding peptide for apolipoprotein E receptor (ApoER-Pep). The microbubble with tailor-made micron size (2 µm) and negative surface charge (-30 mV) performed ApoER-mediated binding rather than internalization into brain capillary endothelial cells. Consequently, the microbubble accumulated on the brain microvessels, based on which even a low-energy ultrasound with less safety risk than FUS, herein diagnostic ultrasound (DUS), could create a strong cavitation effect to open the BBB. Evans Blue and immunofluorescence staining studies demonstrated that the DUS-triggered cavitation effect not only temporarily opened the BBB for 2 h but also caused negligible damage to the brain tissue. Therefore, various agents, ranging from small molecules to nanoscale objects, can be efficiently delivered to target regions of the brain, offering tremendous opportunities for the treatment of brain diseases.

Nanodrug regulates ROS homeostasis via enhancing fatty acid oxidation and inhibiting autophagy to overcome tumor drug resistance.

The treatment of drug-resistant tumors poses a significant challenge in the field of tumor therapy. Disrupting the homeostasis of reactive oxygen species (ROS) within tumor cells may represent a pivotal strategy for overcoming the prevalent issue of drug resistance. However, the restricted sustainability of ROS generation and the increased autophagy capacity exhibited by tumor cells hinder the application of ROS-based therapies. In this study, we developed liposome nanoparticles (Ato/CQ@L) for co-encapsulation of atorvastatin (Ato), an activator of AMP-activated protein kinase (AMPK), and chloroquine (CQ), an autophagy inhibitor. Upon internalization by tumor cells, Ato upregulated carnitine palmitoyltransferase 1(CPT1) concentration and promoted fatty acid oxidation (FAO) within the tumor cells. The process of FAO coupled with an abundance of fatty acid substrates, facilitates a sustained generation of ROS production. Concurrently, a positive feedback loop is established between escalated concentration of ROS and AMPK protein levels, resulting in a persistent elevation in ROS levels. In addition, CQ disrupted lysosomes, leading to an increased lysosomal pH and reducing autophagy in tumor cells. In both in vivo and in vitro experiments, the Ato/CQ@L treatment group exhibited a considerable enhancement in tumor cell apoptosis, validating the efficacy of this combined therapy. In summary, the combined therapy involving Ato and CQ addresses the inherent limitations of conventional ROS therapy, which include insufficient ROS production and increased autophagy. This approach holds significant potential as a treatment strategy for drug-resistant triple-negative breast cancer.

Tumor acidity-activatable macromolecule autophagy inhibitor and immune checkpoint blockade for robust treatment of prostate cancer.

Immune checkpoint blockade (ICB) antibody such as anti-PD-L1 (aPD-L1) activates cytotoxic T cells (CTLs) to combat cancer, but they showed poor efficacy in prostate cancer (PCa). Lysosome-dependent autophagy is utilized by cancer cells to degrade their MHC-I and to lower their vulnerability to TNF-α and CTLs. Lysosomal pH-sensitive polymeric nanoparticle as a drug delivery carrier may also be a novel autophagy inhibitor to boost immunotherapy, but such an important effect has not been investigated. Herein, we developed a unique tumor acidity-activatable macromolecular nanodrug (called P-PDL1-CP) with the poly(2-diisopropylaminoethyl methacrylate) (PDPA) core and the conjugations of both aPD-L1 and long-chain polyethylene glycol (PEG) coating. The PDPA core was demonstrated to disturb lysosome to block the autophagic flux, thus elevating the cancer cell's MHC-I expression and vulnerability to the TNF-α and CTLs. Long-chain PEG facilitated a good tumor accumulation of P-PDL1-CP nanodrug. Furthermore, P-PDL1-CP nanodrug inhibited tumor autophagy, which synergized with aPD-L1 to promote the tumor-infiltrating CTLs and DCs maturation, to elevate intratumoral TNF-α and IFN-γ levels, and to elicit an anti-tumor immune memory effect in mice for PCa growth inhibition with low side effects. This study verified the synergistic anti-PCa treatment between autophagy inhibition and PD-L1 blockade and meantime broadened the application of pH-sensitive macromolecular nanodrug. STATEMENT OF SIGNIFICANCE: A macromolecular nanodrug, comprising the PDPA core and the surface conjugation of both aPD-L1 antibodies and long-chain PEG coating via a tumor acidity-labile α-carboxy-dimethylmaleic anhydride amine bond, was developed. Tumoral acidity triggered the release of aPD-L1 for immunotherapy. Meantime, the charge switch of the remanent nanodrug enhanced the cancer cell uptake of PDPA, which disturbed the lysosomes to inhibit autophagy. This advanced nanodrug promoted the tumor-infiltrating CTLs and DCs maturation, elevated the intratumoral TNF-α and IFN-γ levels, and elicited the robust anti-tumor immune memory effect. This study demonstrated that the pH-sensitive PDPA macromolecule could serve as a carrier for the aPD-L1 delivery and as an efficient autophagy inhibitor to boost the immunotherapy of prostate cancer.

Retinol-binding protein-hijacking nanopolyplex delivering siRNA to cytoplasm of hepatic stellate cell for liver fibrosis alleviation.

Activated hepatic stellate cell (aHSC) is mainly responsible for deposition of extracellular collagen matrix that causes liver fibrosis. Although several siRNAs adequately inhibited HSC activation in vitro, they were demonstrated poor RNAi efficiency in vivo. Developing HSC-targeting and cytoplasmic delivery nanocarrier is highly essential to acquire a desirable siRNA therapeutic index for anti-liver fibrosis. Here, we developed a unique crosslinking nanopolyplex (called T-C-siRNA) modified by vitamin A (VA) with the well-designed natures, including the negative charge, retinol-binding protein (RBP) hijacking, and cytoplasmic siRNA release in response to ROS and cis diol molecules. The nanopolyplex was given a yolk-shell-like shape, camouflage ability in blood, and HSC-targeting capability by hijacking the endogenous ligand RBP via surface VA. PDGFR-ß siRNA (siPDGFR-ß) supplied via T-C-siPDGFR-ß nanopolyplex dramatically reduced HSC activation and its production of pro-fibrogenic proteins in vitro and in vivo. Furthermore, T-C-siPDGFR-ß nanopolyplex effectively alleviated CCl4-induced liver injury, decreased hepatic collagen sediment, and recovered liver function in mice. This study provides a sophisticated method for HSC-targeting cytoplasmic RNA delivery using endogenous ligand hijacking and dual sensitivity of ROS and cis diol compounds.

Nanodrug Augmenting Antitumor Immunity for Enhanced TNBC Therapy via Pyroptosis and cGAS-STING Activation.

Pyroptosis is a proinflammatory form of programmed cell death that results in the release of cellular contents and activation of immune responses. However, GSDME (a pyroptosis-executed protein) is suppressed in many cancers. Herein, we constructed a nanoliposome (GM@LR) for codelivering the GSDME-expressing plasmid and manganese carbonyl (MnCO) into TNBC cells. MnCO generated Mn2+ and carbon monoxide (CO) in the presence of H2O2. The CO-activated caspase-3, which cleaved the expressed GSDME, converting apoptosis to pyroptosis in 4T1 cells. In addition, Mn2+ promoted maturation of dendritic cells (DCs) by the activation of STING signaling pathway. The increased proportion of intratumoral mature DCs brought about massive infiltration of cytotoxic lymphocytes, leading to a robust immune response. Besides, Mn2+ could be applied for magnetic resonance imaging (MRI)-guided metastasis detection. Taken together, our study showed that GM@LR nanodrug could effectively inhibit tumor growth via pyroptosis and STING activation combined immunotherapy.

A hierarchical tumor-targeting strategy for eliciting potent antitumor immunity against triple negative breast cancer.

Triple negative breast cancer (TNBC) as a highly aggressive and metastatic malignancy lacks targeting therapies nowadays. Moreover, although immune checkpoint blockade (ICB) is known to trigger anti-tumor immune response, most TNBC falls into the immunologically "cold" category unsuitable for ICB therapy due to insufficient lymphocyte infiltration. Herein, we develop a hierarchical targeting strategy for preparing a core-shell-structural nanodrug to concurrently block the programmed death ligand 1 (PD-L1) and deliver a stimulator of interferon gene (STING) agonist into tumor-infiltrating antigen-presenting cells (APCs). The nanodrug complexed the interferon stimulatory DNA (ISD) for STING activation in its core, conjugated PD-L1 antibody (aPD-L1) on its shell through a matrix metalloproteinase-2 (MMP-2) substrate peptide, and incorporated "hidden" mannose in its sublayer. Through aPD-L1-mediated active targeting of tumor cells and tumor-infiltrating APCs, the nanodrug efficiently accumulated in tumor sites. Then, the PD-L1-conjugating peptide was cleaved by tumor-enriched MMP-2, leaving aPD-L1 on target cells for ICB while exposing mannose to mediate targeted delivery of ISD into tumor-infiltrating dendritic cells (DCs) and tumor-associated macrophages (TAMs). Activating the STING signaling in DCs and TAMs not only stimulated the APCs maturation to prime anti-tumor immunity but also induced their chemokine secretion to promote tumor infiltration of anti-tumor effector T cells, thus sensitizing TNBC to the ICB therapy. Consequently, a potent antitumor immunity was evoked to effectively inhibit the tumor growth and metastasis in mice bearing orthotopic 4T1 breast cancer, showing the great potential in treating immunologically "cold" tumors.

Inflammation-Regulated Nanodrug Sensitizes Hepatocellular Carcinoma to Checkpoint Blockade Therapy by Reprogramming the Tumor Microenvironment.

Immune checkpoint blockade (ICB) utilizing programmed death ligand-1 (PD-L1) antibody is a promising treatment strategy in solid tumors. However, in fact, more than half of hepatocellular carcinoma (HCC) patients are unresponsive to PD-L1-based ICB treatment due to multiple immune evasion mechanisms such as the hyperactivation of inflammation pathway, excessive tumor-associated macrophages (TAMs) infiltration, and insufficient infiltration of T cells. Herein, an inflammation-regulated nanodrug was designed to codeliver NF-κB inhibitor curcumin and PD-L1 antibody to reprogram the tumor microenvironment (TME) and activate antitumor immunity. The nanodrug accumulated in TME by an enhanced permeability and retention effect, where it left antibody to block PD-L1 on the membrane of tumor cells and TAMs due to pH-responsiveness. Simultaneously, a new curcumin-encapsulated nanodrug was generated, which was easily absorbed by either tumor cells or TAMs to inhibit the nuclear factor kappa-B (NF-κB) signal and related immunosuppressive genes. The inflammation-regulated nanodrug possessed good biocompatibility. Simultaneously, it reprogrammed TME effectively and exhibited an effective anticancer effect in immunocompetent mice. Overall, this study provided a potent strategy to improve the efficiency of ICB-based treatment for HCC.

Nanodrugs Incorporating LDHA siRNA Inhibit M2-like Polarization of TAMs and Amplify Autophagy to Assist Oxaliplatin Chemotherapy against Colorectal Cancer.

Oxaliplatin (OXA) is a first-line chemotherapeutic agent for treating colorectal cancer (CC). However, the chemotherapeutic effect of OXA on CC is limited by the M2-like polarization of tumor-associated macrophages (TAMs) in the tumor microenvironment (TME) and protective autophagy of tumor cells. Here, a cationic polymer APEG-PAsp(PEI) (PAPEI) was prepared to deliver small-interfering RNA (siRNA) to silence the lactate dehydrogenase A (LDHA) gene (LDHA-siRNA) to enhance the chemotherapeutic effect of OXA on CC. The PAPEI/LDHA-siRNA nanocomplex effectively silenced the LDHA gene to inhibit the secretion of lactic acid from tumor cells, resulting in inhibition of the M2-like polarization of TAMs. In addition, the nanocomplex also amplified OXA-induced autophagy and transformed protective autophagy into autophagic death. Consequently, the combination treatment of OXA and PAPEI/LDHA-siRNA showed a dramatically increased chemotherapeutic effect on CC compared with the OXA-alone treatment, which also suggested its attractive potential for treating CC-like immune "cold" tumors.

Nanodrug regulates lactic acid metabolism to reprogram the immunosuppressive tumor microenvironment for enhanced cancer immunotherapy.

A majority of cancers fail to respond to immunotherapy due to the immunosuppressive tumor microenvironment (TME), and metabolic regulation of the TME has been a promising strategy to improve immunotherapy. Lactate is a key metabolic player in tumor immune response since its excess secretion aggravates tumor immune escape by favoring the polarization of tumor-associated macrophages (TAMs) to an immunosuppressive phenotype meanwhile impeding the tumor infiltration of the cytotoxic T lymphocyte. Here, we proposed a metabolic reprogramming mechanism to ameliorate tumor immunosuppression by using lonidamine and syrosingopine incorporated liposomes (L@S/L) to regulate lactate production and efflux. Concretely, lonidamine reduced lactate production by affecting the glycolytic metabolic pathway while syrosingopine decreased lactate efflux by inhibiting the key protein expression of the lactate transporter MCT-4. Consequently, both the drugs synergistically normalize the pH of the TME to overcome the tumor immunosuppressive microenvironment. In vivo studies demonstrated that the decreased extracellular lactate preferentially polarized TAMs to the M1 phenotype, simultaneously increased the proportion of NK cells and reduced the number of Treg cells. These results validated an efficient tumor immunotherapy in the breast cancer model. This new strategy of lactic acid metabolism regulation is proposed to operate in concert with immune modulation in the TME, which shows great potential for immunotherapy of immunologically "cold" tumors.

Surgical Tumor-Derived Photothermal Nanovaccine for Personalized Cancer Therapy and Prevention.

Recent breakthroughs in cell membrane-fabricated nanovaccine offer innovateive therapeutic options for preventing tumor metastasies and recurrence, yet the treatment of patient-specific solid tumor remained challenging owing to the immunosuppressive tumor microenvironment. Herein, we developed a personalized photothermal nanovaccine based on the surgical tumor-derived cell membranes (CMs) coating resiquimod (R848) loaded mesoporous polydopamine (MPDA) nanoparticles for targeting tumor photothermal immunotherapy and prevention. The fabricated photothermal nanovaccine MPDA-R848@CM (MR@C) demonstrates outstanding imaging-guided photothermal immunotherapy efficacy to eradicate solid tumors under near-IR laser irradiation and further inhibiting metastasis tumors by the resulted antitumor immunities, especially in combination with programmed death-ligand 1 antibody therapy (aPD-L1). Furthermore, from in vivo prophylactic testing results, it is confirmed that the 4T1 cells rechallenge can be prevented 100% in postsurgical tumor model after vaccination of the photothermal nanovaccine. Our work fabricates a personalized photothermal nanovaccine that possesses great potential for tumor-specific treatment and for preventing postoperative tumor recurrence.

GSH-Responsive Metal-Organic Framework for Intratumoral Release of NO and IDO Inhibitor to Enhance Antitumor Immunotherapy.

Immunotherapy brings great benefits for tumor therapy in clinical treatments but encounters the severe challenge of low response rate mainly because of the immunosuppressive tumor microenvironment. Multifunctional nanoplatforms integrating effective drug delivery and medical imaging offer tremendous potential for cancer treatment, which may play a critical role in combinational immunotherapy to overcome the immunosuppressive microenvironment for efficient tumor therapy. Here, a nanodrug (BMS-SNAP-MOF) is prepared using glutathione (GSH)-sensitive metal-organic framework (MOF) to encapsulate an immunosuppressive enzyme indoleamine 2,3-dioxygenase (IDO) inhibitor BMS-986205, and the nitric oxide (NO) donor s-nitrosothiol groups. The high T1 relaxivity allows magnetic resonance imaging to monitor nanodrug distribution in vivo. After the nanodrug accumulation in tumor tissue via the EPR effect and subsequent internalization into tumor cells, the enriched GSH therein triggers cascade reactions with MOF, which disassembles the nanodrug to rapidly release the IDO-inhibitory BMS-986205 and produces abundant NO. Consequently, the IDO inhibitor and NO synergistically modulate the immunosuppressive tumor microenvironment with increase CD8+ T cells and reduce Treg cells to result in highly effective immunotherapy. In an animal study, treatment using this theranostic nanodrug achieves obvious regressions of both primary and distant 4T1 tumors, highlighting its application potential in advanced tumor immunotherapy.

COCu: A Robust Self-Regenerative Hydrogel with Applicability as Both Hydrated Gel Dressing and Dry Suture for Seamless Tissue Fixation and Repair.

Self-regenerative hydrogels have recently been developed, and represent a special type of self-healing hydrogels with the ability to restore a dehydrated hydrogel with physical damage. In this study, a self-regenerative hydrogel (COCu) based on two chitosan polymers assembled by slow-released Cu2+ is developed. The COCu hydrogel displays an excellent regeneration ability after being dehydrated and fractured. By simple hydration at room temperature, the fragments of the dehydrated gel fuse into one seamless whole, thereby preserving the mechanical properties and functionalities of the original hydrogel. The regeneration process can be conducted repeatedly after different methods of dehydration (natural volatilization, heat drying, lyophilization) and various modes of deconstruction (flakes, powder, lumpy sponge, etc.). Furthermore, the COCu hydrogel provides ultra-stretchability, and it can be stretched into thin (0.01-0.1 mm) filaments, which, when dried (dtCOCu), can be used as suture lines. Moreover, when used as a dry suture, it regenerates into the hydrogel in the presence of the tissue fluid, forming an excellent sealant to immobilize tissues and seamlessly seal wounds. The fast self-regeneration allows for its facile application as both a hydrated gel dressing and dry suture, and offers customized strategies for fixing and repair of different wounds in soft tissues.

A polymer­calcium phosphate nanocapsule for RNAi-induced oxidative stress and cascaded chemotherapy.

As most of intracellular reactive oxygen species (ROS) is produced in the mitochondria, mitochondrial modulation of cancer cell is a promising strategy for maximizing the in situ-activable combination therapy of oxidative catastrophe and cascaded chemotherapy. Herein, a serum-stable polymer­calcium phosphate (CaP) hybrid nanocapsule carrying siRNA against ADP-ribosylation factor 6 (Arf6) overexpressed in cancer cells and parent drug camptothecin (CPT), designated as PTkCPT/siRNA, was developed for the RNAi-induced oxidative catastrophe and cascaded chemotherapy. A copolymer of mPEG-P(Asp-co-TkCPT), covalently tethered with chemotherapeutic CPT via a ROS-labile dithioketal (Tk) linker, was synthesized and self-assembled into a PTkCPT micelle as a nanotemplate for the CaP mineralization. The as-prepared PTkCPT/siRNA nanoparticle showed a core-shell-distinct nanocapsule which was consisted of a spherical polymeric core enclosed within a CaP shell capable of releasing siRNA in response to lysosomal acidity. Blocking Arf6 signal pathway of cancer cells led to their mitochondrial aggregation and subsequently induced a burst of ROS for oxidative catastrophe, which further triggered the cascaded CPT chemotherapy via the breakage of ROS-labile dithioketal linker. This strategy of RNAi-induced oxidative catastrophe and cascaded chemotherapy resulted in a significant combination effect on cancer cell killing and tumor growth inhibition in mice with low side effects, and provided a promising paradigm for precise cancer therapy.

One-step removal of harmful algal blooms by dual-functional flocculant based on self-branched chitosan integrated with flotation function.

Harmful algal blooms induce severe environmental problems. It is challenging to remove algae by the current available treatments involving complicate process and costly instruments. Here, we developed a CaO2@PEG-loaded water-soluble self-branched chitosan (CP-SBC) system, which can remove algae from water in one-step without additional instrumentation. This approach utilizes a novel flocculant (self-branched chitosan) integrated with flotation function (induced by CaO2@PEG). CP-SBC exhibited better flocculation performance than commercial flocculants, which is attributed to the enhanced bridging and sweeping effect of branched chitosan. CP-SBC demonstrated outstanding biocompatibility, which was verified by zebrafish test and algae activity test. CaO2@PEG-loaded self-branched chitosan can serve as an "Air flotation system" to spontaneous float the flocs after flocculation by sustainably released O2. Furthermore, CP-SBC can improve water quality through minimizing dissolved oxygen depletion and reducing total phosphorus concentrations.

Transparent floatable magnetic alginate sphere used as photocatalysts carrier for improving photocatalytic efficiency and recycling convenience.

Practical application of powder photocatalysts is far from satisfying due to their low photon utilization, inconvenient recovery and potential environmental risk. In this study, an easily recoverable, environmentally friendly and highly transparent floatable magnetic photocatalyst carrier was prepared based on biopolymer alginate and Fe3O4 particles. Further, three different types of photocatalysts were chosen as model semiconductor photocatalysts and loaded on the shell of the carriers. The freeze process facilitated the formation of internal cavities that enhanced floating ability and transparency of the spheres. Meanwhile, the excellent floating performance offered massive reaction sites for pollutants reacting with photocatalysts, O2 and photons on the air/water interface. Photodegradation results showed all three floatable hybrid photocatalysts exhibited enhanced photocatalytic efficiencies compared to the virgin photocatalysts. In short, the carrier can integrate excellent floating ability, environmental friendliness and full recycling with good stability, and it can greatly improve the photocatalytic efficiency of various powder semiconductor photocatalysts.