Stimulation of In Vivo Antitumor Immunity with Hollow Mesoporous Silica Nanospheres

The use of appropriate adjuvants that support the generation of robust and long‐lasting antitumor immune responses is crucial for tumor immunotherapy owing to the immunosuppressive environment of the growing tumor. However, the most commonly used adjuvant, aluminum hydroxide, is ineffective for generating such immune responses and therefore not suitable for cancer immunotherapy. It is now shown that plain hollow mesoporous silica nanospheres markedly improve the antitumor immunity, the Th1 and Th2 immunity, and the CD4⁺ and CD8⁺ effector memory T cell population in bone marrow in vivo and may thus be used as immunoadjuvants to treat cancer in humans.     

Sonodynamic Cytokine Nanocomplexes with Specific Stimulation towards Effector T Cell for Combination Cancer Immunotherapy

Cytokine therapy mediates the interaction between immune cells and non-immune cells in the tumor microenvironment (TME), forming a promising approach in cancer therapy. However, the dose-dependent adverse effects and non-selective stimulation of cytokines limit their clinical use. We herein report a sonodynamic cytokine nano-immunocomplex (SPN_AI) that specifically activates effector T cells (Teffs) for antitumor immunotherapy. By conjugating anti-interleukin-2 (anti-IL-2) antibodies S4B6 on the semiconducting polymer nanoparticles to afford SPN_A, this nanoantibody SPN_A can bind with IL-2 to form SPN_AI which can block the interaction between IL-2 and regulatory T cells (Tregs), selectively activating Teffs in TME. Moreover, SPN_AI generates ¹O₂ to trigger immunogenic cell death of cancer cells upon sono-irradiation, which promotes the maturation of dendritic cells and the proliferation of Teffs. This SPN_AI-mediated combination sonodynamic immunotherapy thus elevates the ratio of Teffs/Tregs in TME, resulting in inhibition of tumor growth, suppression of lung metastasis and prevention of tumor relapse.     

Selective addition of CXCR3+CCR4-CD4+ Th1 cells enhances generation of cytotoxic T cells by dendritic cells in vitro

Increasing importance is being given to the stimulation of Th1 response in cancer immunotherapy because its presence can shift the direction of adaptive immune responses toward protective immunity. Based on chemokine receptor expression, CXCR3⁺CCR4^-CD4⁺ T cells as Th1-type cells were investigated its capacity in monocyte-derived dendritic cell (DC) maturation and polarization, and induction of antigen specific cytotoxic T lymphocytes (CTL) in vitro. The levels of IL-4, IL-5 and IL-10 were decreased to the basal level compared with high production of IFN-γ, TNF-α, and IL-2 in CXCR3⁺CCR4^-CD4⁺ T cells stimulated with anti-CD3 and anti-CD28 antibodies. Co-incubation of activated CD4⁺ or CXCR3⁺CCR4^-CD4⁺ T cells with DC (CD4⁺/DC or CXCR3⁺CD4⁺/DC, respectively) particularly up-regulated IL-12 and CD80 expression compared with DC matured with TNF-α and LPS (mDC). Although there was no significant difference between the effects of the CXCR3⁺CCR4^-CD4⁺ and CD4⁺ T cells on DC phenotype expression, CXCR3⁺CD4⁺/DC in CTL culture were able to expand number of CD8⁺ T cells and increased frequencies of IFN-γ secreting cells and overall cytolytic activity against tumor antigen WT-1. These results demonstrated that the selective addition of CXCR3⁺CCR4^-CD4⁺ T cells to CTL cultures could enhance the induction of CTLs by DC in vitro, and implicated on a novel strategy for adoptive T cell therapy.     

Enhanced antitumor chemo-immunotherapy by local co-delivery of chemotherapeutics,immune checkpoint blocking antibody and IDO inhibitor using an injectable polypeptide hydrogel

The efficiency of antitumor immunotherapy is usually limited by the immunosuppressive tumor microenvironment (TME). In this study, we developed a chemo-immunotherapy strategy that is able to improve the immunosuppressive TME for enhancing the antitumor efficacy. The chemo-immunotherapy was achieved by the topical co-delivery of a chemotherapeutic drug, Doxorubicin (DOX), an immune checkpoint blocking antibody targeting programmed cell death protein 1 (aPD-1), and an indoleamine-2,3-dioxygenase (IDO) inhibitor, 1-methyl-d -tryptophan (d -1MT) by using a thermosensitive polypeptide hydrogel. It was revealed that the sustained DOX release from the hydrogel caused the immunogenic cell death (ICD) of B16F10 cells in vitro, and the tumor cell lysates subsequently promoted the activation of dendritic cells (DCs). After intratumoral injection into B16F10 melanoma-bearing mice, the DOX/aPD-1/D-1MT co-loaded hydrogel exhibited enhanced tumor inhibition efficacy and prolonged animal survival time, compared to the DOX/aPD-1/D-1MT mixed solution, DOX-loaded hydrogel or DOX/aPD-1 co-loaded hydrogel. The improvement of immunosuppressive TME and enhancement of antitumor immune response after the local chemo-immunotherapy were demonstrated by the augmented activation of DCs and increased infiltration of CD8⁺ and CD4⁺ T cells, as well as enhanced secretion of pro-inflammatory cytokines. Therefore, the hydrogel-based local chemo-immunotherapy system holds great potential for effective antitumor treatment.     

In situ Engineering of Tumor-Associated Macrophages via a Nanodrug-Delivering-Drug (β-Elemene@Stanene) Strategy for Enhanced Cancer Chemo-Immunotherapy

Tumor-associated macrophages (TAMs) play a critical role in the immunosuppressive solid tumor microenvironment (TME), yet in situ engineering of TAMs for enhanced tumor immunotherapy remains a significant challenge in translational immuno-oncology. Here, we report an innovative nanodrug-delivering-drug (STNSP@ELE) strategy that leverages two-dimensional (2D) stanene-based nanosheets (STNSP) and β-Elemene (ELE), a small-molecule anticancer drug, to overcome TAM-mediated immunosuppression and improve chemo-immunotherapy. Our results demonstrate that both STNSP and ELE are capable of polarizing the tumor-supportive M2-like TAMs into a tumor-suppressive M1-like phenotype, which acts with the ELE chemotherapeutic to boost antitumor responses. In vivo mouse studies demonstrate that STNSP@ELE treatment can reprogram the immunosuppressive TME by significantly increasing the intratumoral ratio of M1/M2-like TAMs, enhancing the population of CD4⁺ and CD8⁺ T lymphocytes and mature dendritic cells, and elevating the expression of immunostimulatory cytokines in B16F10 melanomas, thereby promoting a robust antitumor response. Our study not only demonstrates that the STNSP@ELE chemo-immunotherapeutic nanoplatform has immune-modulatory capabilities that can overcome TAM-mediated immunosuppression in solid tumors, but also highlights the promise of this nanodrug-delivering-drug strategy in developing other nano-immunotherapeutics and treating various types of immunosuppressive tumors.     

Post translational modification-assisted cancer immunotherapy for effective breast cancer treatment

Post translational modifications (PTM) such as phosphorylation are often correlated with tumorigenesis and malignancy in breast cancer. Herein, we report a PTM-assisted strategy as a simplified version of a personalized cancer vaccine for enhanced cancer immunotherapy. Titanium modified dendritic mesoporous silica nanoparticles (TiDMSN) are applied to assist the specific enrichment of phosphorylated tumor antigens released upon immunogenic cell death. This strategy significantly improved the tumor inhibition efficacy in a bilateral breast cancer model and the expansion of both CD8⁺ and CD4⁺ T cells in the distant tumor site. The nanotechnology based PTM-assisted strategy provides a simple and generalizable methodology for effective personalized cancer immunotherapy.

The nano-enabled post-translational modification assisted strategy for effective cancer immunotherapy.     

Bioorthogonal Reaction-Mediated Tumor-Selective Delivery of CRISPR/Cas9 System for Dual-Targeted Cancer Immunotherapy

CRISPR system-assisted immunotherapy is an attractive option in cancer therapy. However, its efficacy is still less than expected due to the limitations in delivering the CRISPR system to target cancer cells. Here, we report a new CRISPR/Cas9 tumor-targeting delivery strategy based on bioorthogonal reactions for dual-targeted cancer immunotherapy. First, selective in vivo metabolic labeling of cancer and activation of the cGAS-STING pathway was achieved simultaneously through tumor microenvironment (TME)-biodegradable hollow manganese dioxide (H-MnO₂) nano-platform. Subsequently, CRISPR/Cas9 system-loaded liposome was accumulated within the modified tumor tissue through in vivo click chemistry, resulting in the loss of protein tyrosine phosphatase N2 (PTPN2) and further sensitizing tumors to immunotherapy. Overall, our strategy provides a modular platform for precise gene editing in vivo and exhibits potent antitumor response by boosting innate and adaptive antitumor immunity.     

Sodium Bicarbonate Nanoparticles for Amplified Cancer Immunotherapy by Inducing Pyroptosis and Regulating Lactic Acid Metabolism

Although immunotherapy has a broad clinical application prospect, it is still hindered by low immune responses and immunosuppressive tumor microenvironment. Herein, a simple and drug-free inorganic nanomaterial, alkalescent sodium bicarbonate nanoparticles (NaHCO₃ NPs), is prepared via a fast microemulsion method for amplified cancer immunotherapy. The obtained alkalescent NaHCO₃ regulates lactic acid metabolism through acid-base neutralization so as to reverse the mildly acidic immunosuppressive tumor environment. Additionally, it can further release high amounts of Na⁺ ions inside tumor cells and induce a surge in intracellular osmolarity, and thus activate the pyroptosis pathway and immunogenic cell death (ICD), release damage-associated molecular patterns (DAMPs) and inflammatory factors, and improve immune responses. Collectively, NaHCO₃ NPs observably inhibit primary/distal tumor growth and tumor metastasis through acid neutralization remitted immunosuppression and pyroptosis induced immune activation, showing an enhanced antitumor immunity efficiency. This work provides a new paradigm for lactic acid metabolism and pyroptosis mediated tumor treatment, which has a potential for application in clinical tumor immunotherapy.     

Bystander CD4+ T cells: crossroads between innate and adaptive immunity

T cells are the central mediators of both humoral and cellular adaptive immune responses. Highly specific receptor-mediated clonal selection and expansion of T cells assure antigen-specific immunity. In addition, encounters with cognate antigens generate immunological memory, the capacity for long-term, antigen-specific immunity against previously encountered pathogens. However, T-cell receptor (TCR)-independent activation, termed “bystander activation”, has also been found. Bystander-activated T cells can respond rapidly and secrete effector cytokines even in the absence of antigen stimulation. Recent studies have rehighlighted the importance of antigen-independent bystander activation of CD4⁺ T cells in infection clearance and autoimmune pathogenesis, suggesting the existence of a distinct innate-like immunological function performed by conventional T cells. In this review, we discuss the inflammatory mediators that activate bystander CD4⁺ T cells and the potential physiological roles of these cells during infection, autoimmunity, and cancer.Subject terms: T cells, CD4-positive T cells     

Bombyx batryticatus Protein-Rich Extract Induces Maturation of Dendritic Cells and Th1 Polarization: A Potential Immunological Adjuvant for Cancer Vaccine

Bombyx batryticatus, a protein-rich edible insect, is widely used as a traditional medicine in China. Several pharmacological studies have reported the anticancer activity of B. batryticatus extracts; however, the capacity of B. batryticatus extracts as immune potentiators for increasing the efficacy of cancer immunotherapy is still unverified. In the present study, we investigated the immunomodulatory role of B. batryticatus protein-rich extract (BBPE) in bone marrow-derived dendritic cells (BMDCs) and DC vaccine-immunized mice. BBPE-treated BMDCs displayed characteristics of mature immune status, including high expression of surface molecules (CD80, CD86, major histocompatibility complex (MHC)-I, and MHC-II), increased production of proinflammatory cytokines (tumor necrosis factor-α and interleukin-12p70), enhanced antigen-presenting ability, and reduced endocytosis. BBPE-treated BMDCs promoted naive CD4⁺ and CD8⁺ T-cell proliferation and activation. Furthermore, BBPE/ovalbumin (OVA)-pulsed DC-immunized mice showed a stronger OVA-specific multifunctional T-cell response in CD4⁺ and CD8⁺ T cells and a stronger Th1 antibody response than mice receiving differently treated DCs, which showed the enhanced protective effect against tumor growth in E.G7 tumor-bearing mice. Our data demonstrate that BBPE can be a novel immune potentiator for a DC-based vaccine in anticancer therapy.     

A Novel d-Peptide Identified by Mirror-Image Phage Display Blocks TIGIT/PVR for Cancer Immunotherapy

The low response rate and adaptive resistance of PD-1/PD-L1 blockade demands the studies on novel therapeutic targets for cancer immunotherapy. We discovered that a novel immune checkpoint TIGIT expressed higher than PD-1 in many tumors especially anti-PD-1 resistant tumors. Here, mirror-image phage display bio-panning was performed using the d -enantiomer of TIGIT synthesized by hydrazide-based native chemical ligation. d -peptide ^DTBP-3 was identified, which could occupy the binding interface and effectively block the interaction of TIGIT with its ligand PVR. ^DTBP-3 showed proteolytic resistance, tumor tissue penetrating ability, and significant tumor suppressing effects in a CD8⁺ T cell dependent manner. More importantly, ^DTBP-3 could inhibit tumor growth and metastasis in anti-PD-1 resistant tumor model. This is the first d -peptide targeting TIGIT, which could serve as a potential candidate for cancer immunotherapy.     

Oclacitinib,a Janus Kinase Inhibitor,Reduces the Frequency of IL-4- and IL-10-, but Not IFN-γ-, Producing Murine CD4+ and CD8+ T Cells and Counteracts the Induction of Type 1 Regulatory T Cells

The purpose of the present study was to broaden the knowledge and understanding of the effects of oclacitinib (OCL), a Janus kinase inhibitor, on T cells in the context of both the immune mechanisms underlying anti-inflammatory and anti-allergic properties of the drug and its safety. The results indicate that beneficial effects of OCL in the treatment of skin allergic diseases may be partially mediated by the inhibition of IL-4 production in CD4⁺ and CD8⁺ T cells. To a certain extent, the antiproliferative effect of OCL on CD8⁺ T cells may also contribute to its therapeutic effect. The study found that OCL does not affect the proliferation of CD4⁺ T cells or the number of IFN-γ- and IL-17-producing CD4⁺ and CD8⁺ T cells. Moreover, OCL was found to counteract the induction of type 1 regulatory T (Tr1) cells and to act as a strong inhibitor of IL-10 production in both CD4⁺ and CD8⁺ T cells. Thus, these results indicate that beneficial effects of OCL in the treatment of skin allergic diseases are not mediated through: (a) the abolishment of IFN-γ and IL-17-production in CD4⁺ and CD8⁺ T cells; (b) generation of Tr1 cells; (c) inhibition of CD4⁺ T cell proliferation; (d) induction of IL-10 production in CD4⁺ T cells. The results of this study strongly suggest that, with respect to the evaluated parameters, OCL exerts a suppressive effect on Th2- but not Th1-mediated immunity.     

A Novel d‐Peptide Identified by Mirror‐Image Phage Display Blocks TIGIT/PVR for Cancer Immunotherapy

The low response rate and adaptive resistance of PD‐1/PD‐L1 blockade demands the studies on novel therapeutic targets for cancer immunotherapy. We discovered that a novel immune checkpoint TIGIT expressed higher than PD‐1 in many tumors especially anti‐PD‐1 resistant tumors. Here, mirror‐image phage display bio‐panning was performed using the d ‐enantiomer of TIGIT synthesized by hydrazide‐based native chemical ligation. d ‐peptide ^DTBP‐3 was identified, which could occupy the binding interface and effectively block the interaction of TIGIT with its ligand PVR. ^DTBP‐3 showed proteolytic resistance, tumor tissue penetrating ability, and significant tumor suppressing effects in a CD8⁺ T cell dependent manner. More importantly, ^DTBP‐3 could inhibit tumor growth and metastasis in anti‐PD‐1 resistant tumor model. This is the first d ‐peptide targeting TIGIT, which could serve as a potential candidate for cancer immunotherapy.     

Platinum-Based TREM2 Inhibitor Suppresses Tumors by Remodeling the Immunosuppressive Microenvironment

Triggering receptor expressed on myeloid cells-2 (TREM2) is a key pro-tumorigenic marker of tumor-infiltrating macrophages, showing potent immunosuppressive activity in tumor microenvironment. A platinum(IV) complex OPA derived from oxaliplatin (OP) and artesunate (ART) exhibited direct cytotoxicity against human colon cancer cells and immunomodulatory activity to inhibit TREM2 on macrophages in vitro and vivo. Furthermore, OPA deterred the tumor growth in mouse models bearing MC38 colorectal tumor by reducing the number of CD206⁺ and CX₃CR1⁺ immunosuppressive macrophages; it also promoted the expansion and infiltration of immunostimulatory dendritic, cytotoxic T, and natural killer cells. OPA is the first small-molecular TREM2 inhibitor capable of relieving immunosuppressive tumor microenvironment and enhancing chemical anticancer efficiency of a platinum drug, thus showing typical characteristics of a chemoimmunotherapeutic agent.     

Programmed polymersomes with spatio-temporal delivery of antigen and dual-adjuvants for efficient dendritic cells-based cancer immunotherapy

Since antigen and adjuvant are rapid clearance in vivo, insufficient delivery to induce dendritic cells (DCs) maturation and cross-presentation, as well as limited migration efficiency of DCs to secondary lymph organs, greatly hinders the development of DCs-based immunotherapy. Herein, PCL-PEG-PCL polymersomes (PCEP-PS) as antigen and adjuvants delivery nanoplatforms (IMO-PS) were well-designed, which can electrostatically adsorb OVA antigen on the surface via DOTAP lipid and effectively encapsulate OVA antigen into the inner hydrophilic cavity to achieve both initial antigen exposure as well as slow and sustained antigen release, incorporate MPLA within the lipid layer to ligate with extracellular TLR4 of DCs as well as encapsulate IMQ in the hydrophobic membrane to ligate with intracellular TLR7/8 of DCs for activating synergistic immune responses via different signaling pathways. The IMO-PS significantly improved antigen uptake, promoted DCs maturation and cytokines production. DCs treated with IMO-PS could enhance migration into draining lymphoid nodes, and eventually induced antigen-specific CD8⁺ and CD4⁺ T cell responses and OVA-specific cytotoxic T lymphocyte (CTL) responses. Prophylactic vaccination of EG7-OVA tumor-bearing mice by IMO-PS + DCs significantly extended tumor-free time, effectively suppressed tumor growth, and greatly extended median survival time. The strategy may provide an effective nanoplatform for co-delivery antigen and dual-adjuvants in a spatio-temporally programmed manner for DC-based cancer immunotherapy.     

Polymeric STING Pro-agonists for Tumor-Specific Sonodynamic Immunotherapy

The efficacy of combination immunotherapy has been limited by tumor specificity and immune-related adverse events (irAEs). Herein, we report the development of polymeric STING pro-agonists (PSPA), whose sono-immunotherapeutic efficacy is activated by sono-irradiation and elevated glutathione (GSH) within the tumor microenvironment (TME). PSPA is composed of sonosensitizers (semiconducting polymer) and STING agonists (MSA-2) via the GSH-activatable linkers. Under sono-irradiation, PSPA serves as a sonosensitizer to generate ¹O₂ and induce immunogenic cell death (ICD) of malignant tumor cells. Furthermore, MSA-2 is released specifically in tumor microenvironment with highly expressed GSH, minimizing off-target side effects. The activation of the STING pathway elevates the interferon-β level and synergizes with SDT to enhance the anti-tumor response. Therefore, this work proposes a universal approach for spatiotemporal regulation of cancer sono-immunotherapy.