A Microenvironment Dual-Responsive Nano-Drug Equipped with PD-L1 Blocking Peptide Triggers Immunogenic Pyroptosis for Prostate Cancer Self-Synergistic Immunotherapy

Induction of immunogenic cell death (ICD) in tumor combined with immune checkpoint blockade (ICB) therapy is widely developed to improve the efficacy of cancer immunotherapy. However, the current ICD induced based on apoptosis, i.e., immunogenic apoptosis, is often restricted in immunogenicity owing to the inflammatory quenching that occurs early in apoptosis. Recently, pyroptosis is demonstrated to be a more efficient ICD form, i.e., immunogenic pyroptosis. The cell contents released during pyroptosis can powerfully activate tumor immunogenicity. Herein, first, it is demonstrated that lower doses of epigenetic drug decitabine can increase GSDME expression in prostate cancer (PCa) RM-1 cells and successfully induce an apoptosis-pyroptosis transition after photodynamic therapy (PDT). Subsequently, a microenvironment dual-responsive nano-drug equipped with PD-L1 blocking peptide (TSD@LSN-D) is developed for self-synergistic cancer immunotherapy. The poorly immunogenic RM-1 PCa model confirm that the powerful antitumor immune response evoked by TSD@LSN-D not only can effectively inhibit the primary tumor but also form a long-term immune memory to prevent PCa recurrence and metastasis. To the best of authors’ knowledge, this work presents the first concept that promotes the apoptosis–pyroptosis transition after tumor PDT through epigenetic modulation. Furthermore, the powerful combination of immunogenic pyroptosis with ICB opens a new platform for PCa immunotherapy.     

A Metal–Phenolic Nanocoordinator Launches Radiotherapeutic Cancer Pyroptosis Through an Epigenetic Mechanism

Radiotherapy, although clinically effective in immunoactivation, still cannot radio-functionalize tumor as a potent immunogenetic center. Given that newly found pyroptosis efficiently releases immunogenic damage-associated molecular patterns, initiating radiotherapeutic pyroptosis may turn a vision of radiotherapy-induced immunity into reality. However, a precondition is that the absent gasdermin E (GSDME), which essentiates in caspase-3-mediated pyroptosis, can be well translated in cancer cells. Here, an epigenetic strategy to launch cancer pyroptosis in radiotherapy is introduced. The nanocoordinator (PWE) is constructed via a metal–phenolic coordination between polyphenolic DNA methyltransferase inhibitor (epigallocatechin-3-gallate, EGCG), high-Z radiosensitizer (W⁶⁺), and polyphenol-modified block copolymer. While recovering GSDME expression by EGCG, PWE cleaves GSDME into fragmented GSDME N-terminal (pyroptotic key protein) via radiotherapeutic caspase-3. To examine anti-tumor immune activities, PWE amplifies immunological effects of traditional radiotherapy and decreases radiotherapy-upregulated regulatory T cells, providing new insight into tumor radiotherapy.     

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.     

Reshaping Antitumor Immunity with Chemo-Photothermal Integrated Nanoplatform to Augment Checkpoint Blockade-Based Cancer Therapy

Immune checkpoint therapy promotes cytotoxic T lymphocytes (CTLs) activity to eliminate tumors. Nevertheless, their effectiveness in solid tumors is limited by inadequate infiltration of CTLs and suppressive tumor microenvironment (TME). Herein, an anti-PD-1 antibody coupled chemo-photothermal integrated nanoplatform (A/Au@MSMs-P) is proposed to reshape antitumor immunity against cancer. The matrix metalloproteinase-2 (MMP-2) responsive A/Au@MSMs-P promotes the separation of abemaciclib-loaded gold-silica nanoparticles (A/Au@MSMs) and anti-PD-1 antibody, achieving a triple-coordinated strategy to enhance checkpoint blockade therapy. First, chemo-photothermal therapy of A/Au@MSMs induces cell cycle arrest in G1 phase and promotes tumor cells apoptosis to achieve local ablation. Second, immunogenic death of tumor cells promotes the maturation of dendritic cells and recruits antigen-specific CTLs into tumor tissue to promote immune activation. Third, abemaciclib markedly suppresses the proliferation of regulatory T cells (Tregs) to alleviate the immunosuppression of the TME and potentiates the effectiveness of CTLs. This triple-coordinated strategy not only reshapes the antitumor immunity to enhance checkpoint blockade, but also cooperates with chemo-photothermal therapy, leading to improved antitumor efficiency and prolonged survival rate. Taken together, this study presents a promising strategy for improving checkpoint therapy response and has great potential in future cancer therapy.     

Ferroptosis and Pyroptosis Co-Activated Nanomodulator for “Cold” Tumor Immunotherapy and Lung Metastasis Inhibition

Immune checkpoint blockade (ICB) therapy is an emerging strategy for cancer immunotherapy; however, the actual effects of ICB therapy are greatly limited by the immunosuppressive tumor microenvironment (TME, i.e., “cold” tumors). Although engineered nanomaterials display significant importance to regulate TME in cancer treatment, most of them focus on “immunosilent” apoptotic processes that cannot elicit sufficient immune responses for further immunotherapy. Herein, a GSH-responsive nanomodulator is reported that can reverse the immunosuppressive TME for “cold” tumor immunotherapy and lung metastasis inhibition through simultaneous ferroptosis and pyroptosis induction. The nanomodulator is constructed by loading FDA-approved sulfasalazine (SAS) and doxorubicin (DOX) on disulfide-doped organosilica hybrid micelles, where SAS and DOX are released through the GSH-stimulated rupture of micelles to induce ferroptosis and pyroptosis, respectively, promoting dendritic cells (DCs) maturation and cytotoxic T lymphocytes (CTLs) elevation through massive tumor-associated antigen release. In vivo experimental results verify that desirable tumor destruction of the nanomodulator at low concentrations is achieved. More importantly, combination of this nanomodulator and programed death ligand-1 antibodies significantly inhibits primary tumors and distant lung metastases as a result of elevated mature DCs and CTLs. This strategy to modulate immunosuppressive TME by nanomodulator-induced non-apoptotic death provides a new promising paradigm for ICB therapy.     

Inspired Epigenetic Modulation Synergy with Adenosine Inhibition Elicits Pyroptosis and Potentiates Cancer Immunotherapy

Overcoming innate or adaptive resistance to immune checkpoint inhibitor therapy in solid tumors with limited T-cell responses remains challenging. Increasing evidence has indicated that epigenetic alterations, especially overexpression of DNA methyltransferase and immunosuppressive adenosine, are major obstacles to T cell activation. Here, a tumor microenvironment (TME) inspired prodrug nanomicelle (AOZN) composed of the epigenetic modulator γ-oryzanol (Orz), the adenosine inhibitor α, β-methylene adenosine 5′ diphosphate (AMPCP), and GSH-activable crosslinker, is rationally designed. High glutathione redox triggers Orz and AMPCP release in the TME. The released Orz act as a DNA methyltransferases inhibitor to upregulate gasdermin D (GSDMD) expression and AMPCP converted procaspase-1 into active caspase-1 by increasing ATP levels. Active caspase-1 elicited GSDMD cleavage and induced pyroptosis in tumor cells. Furthermore, it is demonstrated that Orz and AMPCP likely have a synergistic effect in combating the immunosuppressive TME. Moreover, Orz enhances programmed death-ligand 1 (PD-L1) expression and sensitize tumors to anti-PD-L1 therapy. Thus, the AOZNs nano-formulation drastically improves the hydrophobic properties of Orz with advantages of safe, affordable, readily available, and efficiency in regressing tumor growth, enhancing PD-L1 responsive rate and prolonging survival of the B16F10 melanoma-bearing mouse model. As a result, AOZNs provides a promising strategy for enhancing cancer immunotherapy.     

Dual Targeted Immunotherapy via In Vivo Delivery of Biohybrid RNAi‐Peptide Nanoparticles to Tumor‐Associated Macrophages and Cancer Cells

Lung cancer is associated with very poor prognosis and considered one of the leading causes of death worldwide. Here, highly potent and selective biohybrid RNA interference (RNAi)‐peptide nanoparticles (NPs) are presented that can induce specific and long‐lasting gene therapy in inflammatory tumor associated macrophages (TAMs), via an immune modulation of the tumor milieu combined with tumor suppressor effects. The data here prove that passive gene silencing can be achieved in cancer cells using regular RNAi NPs. When combined with M2 peptide–based targeted immunotherapy that immuno‐modulates TAMs cell population, a synergistic effect and long‐lived tumor eradication can be observed along with increased mice survival. Treatment with low doses of siRNA (ED₅₀ 0.0025–0.01 mg kg^?1) in a multi and long‐term dosing system substantially reduces the recruitment of inflammatory TAMs in lung tumor tissue, reduces tumor size (≈95%), and increases animal survival (≈75%) in mice. The results here suggest that it is likely that the combination of silencing important genes in tumor cells and in their supporting immune cells in the tumor microenvironment, such as TAMs, will greatly improve cancer clinical outcomes.     

Endogenous Stimuli-Activatable Nanomedicine for Immune Theranostics for Cancer

Cancer immunotherapy has witnessed significant advances in the past decade, however challenges associated with immune-related adverse effects and immunosuppressive tumor microenvironment, have hindered their clinical application. Stimuli-activatable nanomedicines hold great potential for improving the efficiency of cancer immunotherapy and minimizing the side effects via tumor-specific accumulation, controllable drug release profile, and combinational therapy by integrating multiple therapeutic regimens. In this review, the recent advances of stimuli-activatable nanomedicines for cancer immunotherapy are first described, with particular focus on endogenous stimuli including pH, glutathione, reactive oxygen species, and excessive enzymes within the tumor microenvironment. Then, the endogenous stimuli-activatable nanomedicines that target tumor cells, immune cells, or periphery immune systems for eliciting sustained systemic immune activation and modulating the immunosuppressive tumor microenvironment, are described. Next, the general mechanisms underlying nanomedicine-based immunotherapy by eliciting anti-tumor immune responses and overcoming immunologic tolerance are described. Further, the emerging application of bioimaging techniques for monitoring immune response and evaluating therapy performance is described. Finally, the authors’ perspectives are provided for the clinical translation of nanomedicine-based cancer immunotherapy.     

Sono/Photodynamic Nanomedicine-Elicited Cancer Immunotherapy

Immunotherapy (e.g., cancer vaccines and checkpoint blockades), harnessing the host immune system to recognize and eradicate tumors, has emerged as one of the most potent cancer therapies. The clinical applications of cancer immunotherapies, however, have been limited by their low response rates and immune-related adverse effects. In recent years, sono/photodynamic nanomedicines (SPNs) have received increasing attention for cancer therapy since they have been reported to mediate enhanced immunotherapy by generating reactive oxygen species under site-specific exposure to exogenous energy sources. In particular, SPNs are capable of eliciting immunogenic cancer cell death, leading to the release of tumor-associated antigens and damage-associated molecular patterns. This allows for the maturation of antigen-presenting cells, thus eliminating disseminated or metastatic tumor cells by cytotoxic CD8⁺ T cells. Such immunostimulatory features of SPNs provide opportunities to enhance therapeutic potential by amplifying anticancer immunity when combined with conventional immunotherapeutics, including immune checkpoint inhibitors. This review elaborates on the recent strategies and efforts undertaken by researchers to enhance SPN-elicited cancer immunotherapy. The challenging issues and opportunities for SPNs in the activation of innate or adaptive immune responses and regulation of the tumor immunosuppressive microenvironment are also described.     

Macrophage-Mediated Tumor Cell Phagocytosis: Opportunity for Nanomedicine Intervention

Macrophages are one of the most abundant non-malignant cells in the tumor microenvironment, playing critical roles in mediating tumor immunity. As important innate immune cells, macrophages possess the potential to engulf tumor cells and present tumor-specific antigens for adaptive antitumor immunity induction, leading to growing interest in targeting macrophage phagocytosis for cancer immunotherapy. Nevertheless, live tumor cells have evolved to evade phagocytosis by macrophages via the extensive expression of anti-phagocytic molecules, such as CD47. In addition, macrophages also rapidly recognize and engulf apoptotic cells (efferocytosis) in the tumor microenvironment, which inhibits inflammatory responses and facilitates immune escape of tumor cells. Thus, intervention of macrophage phagocytosis by blocking anti-phagocytic signals on live tumor cells or inhibiting tumor efferocytosis presents a promising strategy for the development of cancer immunotherapies. Here, the regulation of macrophage-mediated tumor cell phagocytosis is first summarized, followed by an overview of strategies targeting macrophage phagocytosis for the development of antitumor therapies. Given the potential off-target effects associated with the administration of traditional therapeutics (for example, monoclonal antibodies and small molecule inhibitors), the opportunity for nanomedicine in macrophage phagocytosis intervention is highlighted.     

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.     

Combination of Bacterial‐Photothermal Therapy with an Anti‐PD‐1 Peptide Depot for Enhanced Immunity against Advanced Cancer

Photothermal therapy (PTT) is a promising cancer treatment, but it has so far proven successful only with relatively small subcutaneous tumors in animal models. Treating larger tumors (≈200 mm³) is challenging because most PTT materials do not efficiently reach the hypoxic, avascular center of tumors, and the immunosuppressive tumor microenvironment prevents T cells from fighting against residual tumor cells, thereby allowing recurrence and metastasis. Here, the widely used PTT material polydopamine is coated on the surface of the facultative anaerobe Salmonella VNP20009, which can penetrate deep into larger tumors. The coated bacteria are intravenously injected followed by near‐infrared laser irradiation at the tumor site, combined with a local inoculation of phospholipid‐based phase separation gel containing the anti‐programmed cell death‐1 peptide AUNP‐12. The gel releases AUNP‐12 sustainably during 42 days, maintaining the tumor microenvironment as immunopermissive. Using a mouse model of melanoma, this triple combination of biotherapy, PTT, and sustainable programmed cell death‐1 (PD‐1) blockade shows high efficiency on eliciting robust antitumor immune responses and eliminating relatively large tumors in 50% of animals within 80 days. Thus, the results shed new light on a previously unrecognized immunological facet of bacteria‐mediated therapy, and this innovative triple therapy may be a powerful cancer immunotherapy tool.     

A Combination of Cowpea Mosaic Virus and Immune Checkpoint Therapy Synergistically Improves Therapeutic Efficacy in Three Tumor Models

Immune checkpoint therapy (ICT) has the potential to treat cancer by removing the immunosuppressive brakes on T cell activity. However, ICT benefits only a subset of patients because most tumors are “cold”, with limited pre‐infiltration of effector T cells, poor immunogenicity, and low‐level expression of checkpoint regulators. It has been previously reported that Cowpea mosaic virus (CPMV) promotes the activation of multiple innate immune cells and the secretion of pro‐inflammatory cytokines to induce T cell cytotoxicity, suggesting that immunostimulatory CPMV could potentiate ICT. Here it is shown that in situ vaccination with CPMV increases the expression of checkpoint regulators on Foxp3^?CD4⁺ effector T cells in the tumor microenvironment. It is shown that combined treatment with CPMV and selected checkpoint‐targeting antibodies, specifically anti‐PD‐1 antibodies, or agonistic OX40‐specific antibodies, reduced tumor burden, prolonged survival, and induced tumor antigen‐specific immunologic memory to prevent relapse in three immunocompetent syngeneic mouse tumor models. This study therefore reveals new design principles for plant virus nanoparticles as novel immunotherapeutic adjuvants to elicit robust immune responses against cancer.     

A Supramolecular “Trident” for Cancer Immunotherapy

Immunotherapy has shown great promise for the treatment of cancer. However, the limited efficacy of single-agent immunotherapy hinders its widespread application, which stimulated the investigation of combination therapy with improved efficacy. Herein, a tri-functional immunostimulatory supramolecular nanomedicine consisting of indoximod (IND, an indoleamine 2,3-dioxygenase (IDO) inhibitor), ^DPPA-1 (a D-peptide antagonist against programmed cell death ligand-1 (PD-L1)), and a self-assembling D-tetrapeptide of G^DF^DF^DY (a powerful adjuvant with immunostimulatory properties) is reported. The resulting IND-G^DF^DF^DY-^DPPA-1 behaves as a supramolecular “trident,” and its three functional parts play parallel roles to boost the effective immune responses. It is shown that the supramolecular “trident” exhibits a stronger binding ability to PD-L1 than the ^DPPA-1 peptide (>fourfold) and is able to inhibit the IDO-1 pathway more efficiently than IND itself. The supramolecular “trident” activates and recruits the cytotoxic CD8⁺ T lymphocytes along with other immune effector cells in tumors, concomitant with downregulation of Foxp3⁺ T cells and upregulation of tumor immune-related cytokines, thus showing a strong ability to improve the tumor microenvironment and enhance immunotherapeutic effects to prevent tumor growth and metastasis in the breast tumor model. The findings may stimulate the development of self-assembling peptide-based multifunctional nanomedicines for cancer therapy.     

Size/Charge Changeable Acidity‐Responsive Micelleplex for Photodynamic‐Improved PD‐L1 Immunotherapy with Enhanced Tumor Penetration

The checkpoint blockade‐based immunotherapy has recently emerged as a promising approach for tumor treatment, but its clinical implementation has been impeded by poor tumor penetration of the nanocarriers and activation of antitumor immune response. To overcome the obstacles, a tumor acidity‐responsive micellar nanocomplex co‐loaded with programmed death‐ligand 1 (PD‐L1)‐blockade siRNA and mitochondrion‐targeting photosensitizer for the synergistic integration of photodynamic therapy and immunotherapy is reported in the present study. The nanosystem is coated with long‐circulating polyethylene glycol (PEG) shells, which can be shed in response to the weakly acidic tumor microenvironment and lead to significant size reduction and increasing positive charge. These transitions facilitate penetration and uptake of nanocarriers against tumors. Subsequently, under the mild acidic endo/lysosome condition, the micellar nanocomplexes are rapidly protonated and disintegrated to release the PD‐L1‐blockade siRNA and photosensitizer through sponge effect. Results from in vitro and in vivo experiments collectively reveal that the nanosystem efficiently activates a photodynamic therapy‐induced immune response and silences immune resistance mediated by the checkpoint gene PD‐L1. In consequence, melanoma growth is inhibited and the recurrence rate is reduced via triggering systemic antitumor immune responses. This study offers an alternative strategy for the development of efficient antitumor immune therapy.     

Inhibition of Immunosuppressive Tumors by Polymer‐Assisted Inductions of Immunogenic Cell Death and Multivalent PD‐L1 Crosslinking

Checkpoint blockade immunotherapies harness the host's own immune system to fight cancer, but only work against tumors infiltrated by swarms of preexisting T cells. Unfortunately, most cancers to date are immune‐deserted. Here, a polymer‐assisted combination of immunogenic chemotherapy and PD‐L1 degradation is reported for efficacious treatment in originally nonimmunogenic cancer. “Priming” tumors with backbone‐degradable polymer‐epirubicin conjugates elicits immunogenic cell death and fosters tumor‐specific CD8+ T cell response. Sequential treatment with a multivalent polymer‐peptide antagonist to PD‐L1 overcomes adaptive PD‐L1 enrichment following chemotherapy, biases the recycling of PD‐L1 to lysosome degradation via surface receptor crosslinking, and produces prolonged elimination of PD‐L1 rather than the transient blocking afforded by standard anti‐PD‐L1 antibodies. Together, these findings establish the polymer‐facilitated tumor targeting of immunogenic drugs and surface crosslinking of PD‐L1 as a potential new therapeutic strategy to propagate long‐term antitumor immunity, which might broaden the application of immunotherapy to immunosuppressive cancers.     

Living Cell-Derived Intelligent Nanobots for Precision Oncotherapy

The progress of precision oncology medicine is always limited by the tumor off-targeting, the drug side effects, and the treatment inefficiency due to the complex and ever-changing tumor microenvironment. Living cells, such as blood cells and immune cells, exhibit natural tumor tropism, controllable physicochemical modification, and excellent biocompatibility, which provide an advantageous pathway for innovative and efficient tumor suppression. Armed with nanoengineering techniques, artificial living cells harness their inherent biological properties to precisely identify and eradicate tumors, demonstrating broad biological application prospects and great transformational potential in personalized cancer therapy. Here, the recent advances of living cell-based bionanobots including platelets, red blood cells, neutrophil, macrophage, and CAR-T cells for cancer precision therapy and immune regulation are summarized, and the efficient anti-tumor strategies for engineering living cell nanorobots to overcome complex biological barriers and immune suppression are also outlined (e.g., immunotherapy, sonodynamic therapy, chemo/radiotherapy, and phototherapy). In addition, the study discusses the advantages, limitations, and current challenges of artificial living cell-based drug delivery systems, and provide perspectives on the future development of living cell-mediated precision tumor nanomedicine.     

Synergy of Immunostimulatory Genetherapy with Immune Checkpoint Blockade Motivates Immune Response to Eliminate Cancer

Normalizing the tumor-induced immune deficiency in the immunosuppressive tumor microenvironment (TME) through increasing the efficient infiltration and activation of antitumoral immunity in TME is the core of promising immunotherapy. Herein, a Cyclo(Arg-Gly-Asp-d -Phe-Lys) (RGD) peptides-modified combinatorial immunotherapy system based on the self-assembly of the nanoparticles named RGD-DMA composed of RGD-PEG-PLA, methoxy poly(ethylene glycol)-poly(lactide) (MPEG-PLA) and 1,2-Dioleoyl-3-trimethylammonium-propane (DOTAP) is used to codeliver the immunostimulatory chemokine CCL19-encoding plasmid DNA (CCL19 pDNA) and immune checkpoint ligand PD-L1 inhibitor (BMS-1). The RGD-DMA/pCCL19-BMS-1 system not only exhibited significant inhibition of tumor progression but also induced locally high concentrations of immunostimulatory cytokines at tumor sites without causing an obviously systemic inflammatory response. The immunosuppressive TME is efficaciously reshaped by the coadministration of RGD-DMA/pCCL19 and BMS-1, as indicated by the activated T lymphocytes, increased intratumoral-infiltration of mature dendritic cells (DCs), and the repolarization of macrophages from pro-tumoral M2-phenotype toward tumoricidal M1-phenotype. The upregulated PD-L1 expression at tumor sites caused by the increased IFN-γ levels after immunostimulatory gene therapy further demonstrated the synergistic effects of BMS-1 in counteracting the inhibitory role of PD-L1 expression in antitumor immunity. Therefore, the combination of immunostimulating therapy and immune checkpoint inhibitor that synergistically target multiple immune regulatory pathways demonstrates significant potential as a novel immunotherapy approach.     

Biodegradable Polymeric Nanoparticles Containing an Immune Checkpoint Inhibitor (aPDL1) to Locally Induce Immune Responses in the Central Nervous System

Immunotherapy is an efficient approach to clinical oncology. However, the immune privilege of the central nervous system (CNS) limits the application of immunotherapeutic strategies for brain cancers, especially glioblastoma (GBM). Tumor resistance to immune checkpoint inhibitors is a further challenge in immunotherapies. To overcome the immunological tolerance of brain tumors, a novel multifunctional nanoparticle (NP) for highly efficient synergetic immunotherapy is reported. The NP contains an anti-PDL1 antibody (aPDL1), upconverting NPs, and the photosensitizer 5-ALA; the surface of the NP is conjugated with the B1R kinin ligand to facilitate transport across the blood-tumor-barrier. Upon irradiation with a 980 nm laser, 5-ALA is transformed into protoporphyrin IX, generating reactive oxygen species. Photodynamic therapy (PDT) further promotes intratumoral infiltration of cytotoxic T lymphocytes and sensitizes tumors to PDL1 blockade therapy. It is demonstrated that combining PDT and aPDL1 can effectively suppress GBM growth in mouse models. The proposed NPs provide a novel and effective strategy for boosting anti-GBM photoimmunotherapy.     

A Near-Infrared Light-Responsive ROS Cascade Nanoplatform for Synergistic Therapy Potentiating Antitumor Immune Responses

Tumor occurrence is closely related to the unlimited proliferation and the evasion of the immune surveillance. However, it remains a challenge to kill tumor cells and simultaneously activate antitumor immunity upon spatially localized external stimuli. Herein, a robust tumor synergistic therapeutic nanoplatform is designed in combination with dual photosensitizers-loaded upconversion nanoparticles (UCNPs) and ferric-tannic acid (FeTA) nanocomplex. Dual photosensitizers-loaded UCNPs can induce photodynamic therapy (PDT) effect by generation of cytotoxic reactive oxygen species (ROS) on demand under near-infrared (NIR) light irradiation. FeTA can robustly respond to acidic tumor microenvironment to produce Fe²⁺ and subsequently induce chemodynamic therapy (CDT) by reacting with H₂O₂ in the tumor microenvironment. More importantly, the CDT/PDT synergy can not only exhibit significant antitumor ability but also induce ROS cascade to evoke immunogenic cell death. It increases tumor immunogenicity and promotes immune cell infiltration at tumor sites allowing further introduction of systemic immunotherapy responsiveness to inhibit the primary and distant tumor growth. This study provides a potential tumor microenvironment-responsive nanoplatform for imaging-guided diagnosis and combined CDT/PDT with improved immunotherapy responses and an external NIR-light control of photoactivation.