A PD-L1-targeting Regulator for Metabolic Reprogramming to Enhance Glutamine Inhibition-Mediated Synergistic Antitumor Metabolic and Immune Therapy.

Inhibition of glutamine metabolism in tumor cells can cause metabolic compensation-mediated glycolysis enhancement and PD-L1 upregulation-induced immune evasion, significantly limiting the therapeutic efficacy of glutamine inhibitors. Here, inspired by the specific binding of receptor and ligand, a PD-L1-targeting metabolism and immune regulator (PMIR) are constructed by decorating the glutaminase inhibitor (BPTES)-loading zeolitic imidazolate framework (ZIF) with PD-L1-targeting peptides for regulating the metabolism within the tumor microenvironment (TME) to improve immunotherapy. At tumor sites, PMIR inhibits glutamine metabolism of tumor cells for elevating glutamine levels within the TME to improve the function of immune cells. Ingeniously, the accompanying PD-L1 upregulation on tumor cells causes self-amplifying accumulation of PMIR through PD-L1 targeting, while also blocking PD-L1, which has the effects of converting enemies into friends. Meanwhile, PMIR exactly offsets the compensatory glycolysis, while disrupting the redox homeostasis in tumor cells via the cooperation of components of the ZIF and BPTES. These together cause immunogenic cell death of tumor cells and relieve PD-L1-mediated immune evasion, further reshaping the immunosuppressive TME and evoking robust immune responses to effectively suppress bilateral tumor progression and metastasis. This work proposes a rational strategy to surmount the obstacles in glutamine inhibition for boosting existing clinical treatments.

Immunoadjuvant-Modified Rhodobacter sphaeroides Potentiate Cancer Photothermal Immunotherapy.

Photothermal immunotherapy has become a promising strategy for tumor treatment. However, the intrinsic drawbacks like light instability, poor immunoadjuvant effect, and poor accumulation of conventional inorganic or organic photothermal agents limit their further applications. Based on the superior carrying capacity and active tumor targeting property of living bacteria, an immunoadjuvant-intensified and engineered tumor-targeting bacterium was constructed to achieve effective photothermal immunotherapy. Specifically, immunoadjuvant imiquimod (R837)-loaded thermosensitive liposomes (R837@TSL) were covalently decorated onto Rhodobacter sphaeroides (R.S) to obtain nanoimmunoadjuvant-armed bacteria (R.S-R837@TSL). The intrinsic photothermal property of R.S combined R837@TSL to achieve in situ near-infrared (NIR) laser-controlled release of R837. Meanwhile, tumor immunogenic cell death (ICD) caused by photothermal effect of R.S-R837@TSL, synergizes with released immunoadjuvants to promote maturation of dendritic cells (DCs), which enhance cytotoxic T lymphocytes (CTLs) infiltration for further tumor eradication. The photosynthetic bacteria armed with immunoadjuvant-loaded liposomes provide a strategy for immunoadjuvant-enhanced cancer photothermal immunotherapy.

Immunostimulant Hydrogel-Guided Tumor Microenvironment Reprogramming to Efficiently Potentiate Macrophage-Mediated Cellular Phagocytosis for Systemic Cancer Immunotherapy.

Macrophage-mediated cellular phagocytosis (MMCP) plays a critical role in conducting antitumor immunotherapy but is usually impaired by the intrinsic phagocytosis evading ability of tumor cells and the immunosuppressive tumor microenvironment (TME). Herein, a MMCP-boosting hydrogel (TCCaGM) was elaborately engineered by encapsulating granulocyte-macrophage colony-stimulating factor (GM-CSF) and a therapeutic nanoplatform (TCCaN) that preloaded with the tunicamycin (Tuni) and catalase (CAT) with the assistance of CaCO3 nanoparticles (NPs). Strikingly, the hypoxic/acidic TME was efficiently alleviated by the engineered hydrogel, "eat me" signal calreticulin (CRT) was upregulated, while the "don't eat me" signal CD47 was downregulated on tumor cells, and the infiltrated DCs were recruited and activated, all of which contributed to boosting the macrophage-mediated phagocytosis and initiating tumor-specific CD8+ T cells responses. Meanwhile, the remodeled TME was beneficial to accelerate the polarization of tumor-associated macrophages (TAMs) to the antitumoral M1-like phenotype, further heightening tumoricidal immunity. With the combination of PD-1 antibody (αPD-1), the designed hydrogel significantly heightened systemic antitumor immune responses and long-term immunological effects to control the development of primary and distant tumors as well as suppress tumor metastasis and recurrence, which established an optimal strategy for high-performance antitumor immunotherapy.

Engineering metal-based hydrogel-mediated tertiary lymphoid structure formation via activation of the STING pathway for enhanced immunotherapy.

Tertiary lymphoid structures (TLSs) primarily constructed by multiple immune cells can effectively enhance tumor immune responses, but expediting the formation of TLSs is still an enormous challenge. Herein, a stimulator of interferon gene (STING)-activating hydrogel (ZCCG) was elaborately developed by coordinating Zn2+ with 4,5-imidazole dicarboxylic acid, and simultaneously integrating chitosan (a stimulant of STING pathway activation) and CpG (an agonist of toll-like receptor 9, TLR9) for initiating and activating cGAS-STING and TLR9 pathway-mediated immunotherapy. Moreover, the dual-pathway activation could effectively enhance the infiltration of immune cells and the expression of lymphocyte-recruiting chemokines in the tumor microenvironment (TME), thereby promoting the formation of TLSs and further strengthening tumoricidal immunity. Local administration of the hydrogel could prime systemic immune responses and long-term immune memory and improve the therapeutic effects of programmed death-1 antibody (αPD-1) to inhibit tumor progression, metastasis and recurrence. The engineered hydrogel lays the foundation for tumor immunotherapy strategies based on the enhanced formation of TLSs via the activation of the cGAS-STING and TLR9 pathways.

Nanoparticles Hitchhike on Monocytes for Glioblastoma Treatment after Low-Dose Radiotherapy.

Glioblastomas (GBMs) are aggressive primary brain tumors with fatal outcome. Traditional chemo-radiotherapy has poor therapeutic effect and significant side effects, due to the drug and radiotherapy (RT) resistance, natural blood-brain barrier, and high-dose RT damage. Even more, tumor-associated monocytes (macrophages and microglia, TAMs) constitute up to 30%-50% of the GBM cellular content, and the tumor microenvironment (TME) in GBM is extremely immunosuppressive. Here, we synthesized nanoparticles (D@MLL) that hitchhike on circulating monocytes to target intracranial GBMs with the assistance of low-dose RT. The chemical construction of D@MLL was DOX·HCl loaded MMP-2 peptide-liposome, which could target monocytes by the surface modified lipoteichoic acid. First, low-dose RT at the tumor site increases monocyte chemotaxis and induces M1 type polarization of TAMs. Subsequently, the intravenous injected D@MLL targets circulating monocytes and hitchhikes with them to the central site of the GBM area. DOX·HCl was then released by the MMP-2 response, inducing immunogenic cell death, releasing calreticulin and high-mobility group box 1. This further contributed to TAMs M1-type polarization, dendritic cell maturation, and T cell activation. This study demonstrates the therapeutic advantages of D@MLL delivered by endogenous monocytes to GBM sites after low-dose RT, and it provides a high-precision treatment for GBMs.

Inhalable Capsular Polysaccharide-Camouflaged Gallium-Polyphenol Nanoparticles Enhance Lung Cancer Chemotherapy by Depleting Local Lung Microbiota.

Local lung microbiota is closely associated with lung tumorigenesis and therapeutic response. It is found that lung commensal microbes induce chemoresistance in lung cancer by directly inactivating therapeutic drugs via biotransformation. Accordingly, an inhalable microbial capsular polysaccharide (CP)-camouflaged gallium-polyphenol metal-organic network (MON) is designed to eliminate lung microbiota and thereby abrogate microbe-induced chemoresistance. As a substitute for iron uptake, Ga3+ released from MON acts as a "Trojan horse" to disrupt bacterial iron respiration, effectively inactivating multiple microbes. Moreover, CP cloaks endow MON with reduced immune clearance by masquerading as normal host-tissue molecules, significantly increasing residence time in lung tissue for enhanced antimicrobial efficacy. In multiple lung cancer mice models, microbe-induced drug degradation is remarkably inhibited when drugs are delivered by antimicrobial MON. Tumor growth is sufficiently suppressed and mouse survival is prolonged. The work develops a novel microbiota-depleted nanostrategy to overcome chemoresistance in lung cancer by inhibiting local microbial inactivation of therapeutic drugs.

Specific activation of cGAS-STING pathway by nanotherapeutics-mediated ferroptosis evoked endogenous signaling for boosting systemic tumor immunotherapy.

Activation of the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway could effectively initiate antitumor immunity, but specific activation of STING pathway is still an enormous challenge. Herein, a ferroptosis-induced mitochondrial DNA (mtDNA)-guided tumor immunotherapy nanoplatform (designated as HBMn-FA) was elaborately developed for activating and boosting STING-based immunotherapy. On the one hand, the high-levels of reactive oxygen species (ROS) in tumor cells induced by HBMn-FA-mediated ferroptosis elicited mitochondrial stress to cause the release of endogenous signaling mtDNA, which specifically initiate cGAS-STING pathway with the cooperation of Mn2+. On the other hand, the tumor-derived cytosolic double-stranded DNA (dsDNA) from debris of death cells caused by HBMn-FA further activated the cGAS-STING pathway in antigen-presenting cells (e.g., DCs). This bridging of ferroptosis and cGAS-STING pathway could expeditiously prime systemic antitumor immunity and enhance the therapeutic efficacy of checkpoint blockade to suppress tumor growth in both localized and metastatic tumor models. The designed nanotherapeutic platform paves the way for novel tumor immunotherapy strategies that are based on specific activation of STING pathway.

Multifunctional liquid metal-based nanoparticles with glycolysis and mitochondrial metabolism inhibition for tumor photothermal therapy.

Tumor cells obtain energy supply from different metabolic pathways to maintain survival. In this study, a tumor acidity-responsive spherical nanoparticle (called as LMGC) was designed by attaching glucose oxidase (GOx) and mineralizing calcium carbonate on the surface of liquid metal nanoparticles to integrate the synergistic effect of adenosine triphosphate (ATP) generation inhibition and photothermal therapy (PTT) for enhanced tumor therapy. After GOx catalysis, the process of glycolysis was inhibited, and the increased H2O2 level enhanced the intratumoral oxidative stress. Besides, the gluconic acid production accelerated the degradation of LMGC and promoted Ca2+-mediated mitochondrial dysfunction. The inhibition of glycolysis and mitochondrial metabolism could significantly reduce ATP production and down-regulate heat shock protein (HSP) expression, which would reduce tumor cells heat resistance and improve PTT therapeutic effect. This liquid metal-based ATP inhibition system with enhanced therapeutic effect will find great potential for tumor treatment.

Neisseria meningitidis Opca Protein/MnO2 Hybrid Nanoparticles for Overcoming the Blood-Brain Barrier to Treat Glioblastoma.

The major hurdle in glioblastoma therapy is the low efficacy of drugs crossing the blood-brain barrier (BBB). Neisseria meningitidis is known to specifically enrich in the central nervous system through the guidance of an outer membrane invasion protein named Opca. Here, by loading a chemotherapeutic drug methotrexate (MTX) in hollow manganese dioxide (MnO2 ) nanoparticles with surface modification of the Opca protein of Neisseria meningitidis, a bionic nanotherapeutic system (MTX@MnO2 -Opca) is demonstrated to effectively overcome the BBB. The presence of the Opca protein enables the drug to cross the BBB and penetrate into tumor tissues. After accumulating in glioblastoma, the nanotherapeutic system catalyzes the decomposition of excess H2 O2 in the tumor tissue and thereby generates O2 , which alleviates tumor hypoxia and enhances the effect of chemotherapy in the treatment of glioblastoma. This bionic nanotherapeutic system may exhibit great potential in the treatment of glioblastoma.

Multifunctionalized Gold Sub-Nanometer Particles for Sensitizing Radiotherapy against Glioblastoma.

Glioblastoma is the most common lethal malignant intracranial tumor with a low 5-year survival rate. Currently, the maximal safe surgical resection, followed by high-dose radiotherapy (RT), is a standard treatment for glioblastoma. However, high-dose radiation to the brain is associated with brain injury and results in a high fatality rate. Here, integrated pharmaceutics (named D-iGSNPs) composed of gold sub-nanometer particles (GSNPs), blood-brain barrier (BBB) penetration peptide iRGD, and cell cycle regulator α-difluoromethylornithine is designed. In both simulated BBB and orthotopic murine GL261 glioblastoma models, D-iGSNPs are proved to have a beneficial effect on the BBB penetration and tumor targeting. Meanwhile, data from cell and animal experiments reveal that D-iGSNPs are able to sensitize RT. More importantly, the synergy of D-iGSNPs with low-dose RT can exhibit an almost equal therapeutic effect with that of high-dose RT. This study demonstrates the therapeutic advantages of D-iGSNPs in boosting RT, and may provide a facile approach to update the current treatment of glioblastoma.

Vascular disrupting agent induced aggregation of gold nanoparticles for photothermally enhanced tumor vascular disruption.

Although vascular disrupting agents (VDAs) have been extensively implemented in current clinical tumor therapy, the notable adverse events caused by long-term dosing severely limit the therapeutic efficacy. To improve this therapy, we report a strategy for VDA-induced aggregation of gold nanoparticles to further destroy tumor vascular by photothermal effect. This strategy could effectively disrupt tumor vascular and cut off the nutrition supply after just one treatment. In the murine tumor model, this strategy results in notable tumor growth inhibition and gives rise to a 92.7% suppression of tumor growth. Besides, enhanced vascular damage could also prevent cancer cells from distant metastasis. Moreover, compared with clinical therapies, this strategy still exhibits preferable tumor suppression and metastasis inhibition ability. These results indicate that this strategy has great potential in tumor treatment and could effectively enhance tumor vascular damage and avoid the side effects caused by frequent administration.