Synergistic Cancer Immunotherapy Research Articles

Cinnamaldehyde-based poly(thioacetal): A ROS-awakened self-amplifying degradable polymer for enhanced cancer immunotherapy

Although stimuli-responsive polymers have emerged as promising strategies for intelligent cancer therapy, limited polymer degradation and insufficient drug release remain a challenge. Here, we report a novel reactive oxygen species (ROS)-awakened self-amplifying degradable cinnamaldehyde (CA)-based poly(thioacetal) polymer. The polymer consists of ROS responsive thioacetal (TA) group and CA as the ROS generation agent. The self-amplified polymer degradation process is triggered by endogenous ROS-induced cleavage of the TA group to release CA. The CA released then promotes the generation of more ROS through mitochondrial dysfunction, resulting in amplified polymer degradation. More importantly, poly(thioacetal) itself can trigger immunogenic cell death (ICD) of the tumor cells and its side chains can be conjugated with indoleamine 2,3-dioxygenase 1 (IDO-1) inhibitor to reverse the immunosuppressive tumor microenvironment for synergistic cancer immunotherapy. The self-amplified degradable poly(thioacetal) developed in this work provides insights into the development of novel stimulus-responsive polymers for enhanced cancer immunotherapy.

A prodrug hydrogel with tumor microenvironment and near-infrared light dual-responsive action for synergistic cancer immunotherapy

Immunotherapy has been used for cancer treatment, while it faces the common dilemmas of low therapeutic efficacy and serious immunotoxicity. In this study, we report the construction of a tumor microenvironment and near-infrared (NIR) light dual-responsive prodrug hydrogel for cancer synergistic immunotherapy in a more effective and safe manner. Such prodrug hydrogels were in-situ formed via calcium-induced gelation of alginate solution containing protoporphyrin IX (PpIX)‐modified iron oxide (Fe3O4) nanoparticles and programmed death ligand 1 antibody (aPD-L1) prodrug nanoparticles crosslinked by reactive oxygen species (ROS)-responsive linkers. PpIX served as a photosensitizer to produce singlet oxygen (1O2) under NIR laser irradiation for photodynamic therapy (PDT), and Fe3O4 nanoparticles mediated chemodynamic therapy (CDT) to generate hydroxyl radical (·OH) via Fenton reaction in the tumor microenvironment. In view of the cumulative actions of PDT and CDT, amplified ROS was generated to not only induce immunogenic cell death (ICD), but also destroy ROS-responsive linkers to achieve on-demand release of aPD-L1 from prodrug nanoparticles. Boosted antitumor immunity was elicited in tumor-bearing mice due to the aPD-L1-mediated immune checkpoint blocking. As a result, the prodrug hydrogel-based synergistic immunotherapy could almost treat bilateral tumors and prevent lung and liver metastasis using 4T1 tumor mouse models. This study thus offers a dual-responsive prodrug hydrogel platform for precision cancer immunotherapy. Statement of significanceVia calcium-induced gelation of alginate, we constructed a prodrug hydrogel with tumor microenvironment and near-infrared light dual-responsive action for synergistic cancer immunotherapy. Such hydrogels can achieve on-demand release of aPD-L1 upon photoactivation in the tumor microenvironment. Through mediating photodynamic and chemodynamic therapy, the prodrug hydrogels can induce enhanced immunogenic cell death and synergistically improve the efficacy of aPD-L1-mediated immune checkpoint blocking. The prodrug hydrogel-based synergistic therapy almost deracinates the primary and distant tumors, and prevents lung and liver metastasis in tumor mouse models.

A prodrug nanoplatform via esterification of STING agonist and IDO inhibitor for synergistic cancer immunotherapy

A prodrug nanoplatform via esterification of STING agonist and IDO inhibitor for synergistic cancer immunotherapy

Two-Pronged Intracellular Co-Delivery of Antigen and Adjuvant for Synergistic Cancer Immunotherapy.

Nanovaccines have emerged as promising alternatives or complements to conventional cancer treatments. Despite the progresses, specific co-delivery of antigen and adjuvant to their corresponding intracellular destinations for maximizing the activation of antitumor immune responses remains a challenge. Herein, a lipid-coated iron oxide nanoparticle is delivered as nanovaccine (IONP-C/O@LP) that can co-deliver peptide antigen and adjuvant (CpG DNA) into cytosol and lysosomes of dendritic cells (DCs) through both membrane fusion and endosome-mediated endocytosis. Such two-pronged cellular uptake pattern enables IONP-C/O@LP to synergistically activate immature DCs. Iron oxide nanoparticle also exhibits adjuvant effects by generating intracellular reactive oxygen species, which further promotes DC maturation. IONP-C/O@LP accumulated in the DCs of draining lymph nodes effectively increases the antigen-specific T cells in both tumor and spleen, inhibits tumor growth, and improves animal survival. Moreover, it is demonstrated that this nanovaccine is a general platform of delivering clinically relevant peptide antigens derived from human papilloma virus 16 to trigger antigen-specific immune responses in vivo.

Stimuli-Responsive Nanoparticles for Controlled Drug Delivery in Synergistic Cancer Immunotherapy.

Cancer immunotherapy has achieved promising clinical progress over the recent years for its potential to treat metastatic tumors and inhibit their recurrences effectively. However, low patient response rates and dose‐limiting toxicity remain as major dilemmas for immunotherapy. Stimuli‐responsive nanoparticles (srNPs) combined with immunotherapy offer the possibility to amplify anti‐tumor immune responses, where the weak acidity, high concentration of glutathione, overexpressions of enzymes, and reactive oxygen species, and external stimuli in tumors act as triggers for controlled drug release. This review highlights the design of srNPs based on tumor microenvironment and/or external stimuli to combine with different anti‐tumor drugs, especially the immunoregulatory agents, which eventually realize synergistic immunotherapy of malignant primary or metastatic tumors and acquire a long‐term immune memory to prevent tumor recurrence. The authors hope that this review can provide theoretical guidance for the construction and clinical transformation of smart srNPs for controlled drug delivery in synergistic cancer immunotherapy.

Micelle nanovehicles for co-delivery of Lepidium meyenii Walp. (maca) polysaccharide and chloroquine to tumor-associated macrophages for synergistic cancer immunotherapy

Here, we fabricated amphiphilic polysaccharide micelles for synergistic cancer immunotherapy targeting tumor-associated macrophages (TAMs). Lepidium meyenii Walp. (maca) polysaccharide (MP), a naturally derived macromolecule with a strong TAM-remodeling effect, was grafted on a hydrophobic poly(lactic-co-glycolic acid) (PLGA) segment, with a disulfide bond for redox-sensitive linkage. The amphiphilic polysaccharide derivatives could self-assemble into core (PLGA)–shell (MP)-structured micelles and encapsulate chloroquine (CQ) into the hydrophobic core. By using a 4T1-M2 macrophage co-culture model and a 4T1 tumor xenograft mouse model, we showed that the prepared micelles could co-deliver MP and CQ to the tumor sites and selectively accumulate at TAMs because of the specific properties of MP. Furthermore, the nanoparticles exerted synergistic tumor immunotherapeutic and antimetastatic effects, which might be attributable to the enhanced cell internalization of the micelles and the multiple regulatory mechanisms of MP and CQ. Thus, immunomodulatory MP may be a promising biomaterial for cancer immunotherapy.

Engineering Prodrug Nanomedicine for Cancer Immunotherapy.

Immunotherapy has shifted the clinical paradigm of cancer management. However, despite promising initial progress, immunotherapeutic approaches to cancer still suffer from relatively low response rates and the possibility of severe side effects, likely due to the low inherent immunogenicity of tumor cells, the immunosuppressive tumor microenvironment, and significant inter‐ and intratumoral heterogeneity. Recently, nanoformulations of prodrugs have been explored as a means to enhance cancer immunotherapy by simultaneously eliciting antitumor immune responses and reversing local immunosuppression. Prodrug nanomedicines, which integrate engineering advances in chemistry, oncoimmunology, and material science, are rationally designed through chemically modifying small molecule drugs, peptides, or antibodies to yield increased bioavailability and spatiotemporal control of drug release and activation at the target sites. Such strategies can help reduce adverse effects and enable codelivery of multiple immune modulators to yield synergistic cancer immunotherapy. In this review article, recent advances and translational challenges facing prodrug nanomedicines for cancer immunotherapy are overviewed. Last, key considerations are outlined for future efforts to advance prodrug nanomedicines aimed to improve antitumor immune responses and combat immune tolerogenic microenvironments.

Abstract LB-095: Synergistic cancer immunotherapy using tumor tissue derived exosomes and artificially produced bacterial outer membrane vesicles

Abstract Checkpoint inhibitors work only in cancers that host inflammatory cells, and “cold” tumors normally do not respond. Therefore, making “cold” tumors “hot” is required to increase the response rate to immunooncology therapies in general. Bacteria and bacterial products have been utilized for cancer immunotherapy for more than 100 years, but currently no such treatment is available because of the severe side effects that are observed. In this study, we produced artificial outer membrane vesicles (aOMVs) from Escherichia coli outer membrane, and injected them together with cancer tissue-derived exosomes to booster an immune response to the malignancy. Firstly, outer membranes were obtained from E. coli by chemical means, followed by ionic stress and applied mild energy to generate aOMVs. The yield and purity of aOMVs were analyzed by nanoparticle tracking analysis and transmission electron microscopy. The protein and RNA contents were examined by label-free quantitative mass spectrometry and bioanalyzer. Inflammation was evaluated in macrophage cell line (RAW 264.7) and mice in vivo, and bone marrow-derived dendritic cells were used to assess the immunomodulatory functions of the aOMVs. For the study of antitumor activity, mice were subcutaneously inoculated with B16F10 cells and then subcutaneously immunized with aOMVs and melanoma exosomes five times at 3-day intervals. Also, anti-mouse PD-1 antibody was intraperitoneally injected into mice 1 day prior to immunization to investigate the effects of combination therapy. To elucidate the immunogenic mechanism, blood and spleen were obtained for antibody titer and splenocyte function study. As a result, bacterial aOMVs presented nanosized spherical shape with closed membranes and exhibited high yield and purity with very few cytosolic components. These aOMVs do not cause pro-inflammatory cytokine responses in RAW 264.7 cells and mice in vivo, despite high exposure levels. The aOMVs could be taken up by dendritic cells to stimulate cytokine and maturation marker expression. Co-immunization with aOMVs and melanoma tissue-derived exosomes elicited tumor regression in melanoma-bearing mice through Th-1 type T cell immunity and anti-tumor exosome IgG antibody production. Also, the immunotherapeutic effect of aOMVs was synergistically enhanced by anti-PD-1 inhibitor. Collectively, bacterial aOMVs can be produced in a large quantities with high purity, but are “detoxified" compared to naturally released OMVs. The non-toxic aOMVs are powerful adjuvants for eliciting specific anti-tumor response, suggesting that aOMVs may be novel bacterial vesicle-mimetics clinically applicable as cancer treatment. Citation Format: Kyong-su Park, Kristina Svennerholm, Rossella Crescitelli, Cecilia Lässer, Inta Gribonika, Jan Lötvall. Synergistic cancer immunotherapy using tumor tissue derived exosomes and artificially produced bacterial outer membrane vesicles [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-095.

Abstract 1598: Reprogramming of immunosuppressive tumor microenvironments by multifunctional nanoemulsion and enhance immune checkpoint blockade therapy

Abstract The low response rate of current cancer immunotherapy suggests the presence of few antigen-specific T cells and a high number of immunosuppressive factors in tumor microenvironment (TME). Toll-like receptor (TLR) 7/8 agonist-based adjuvants have been widely used to activate antigen-presenting cells (APCs) and induce antigen-specific therapeutic T cells. However, the incorporation of TLR 7/8 agonists also induces immunosuppressive factors, such as Indoleamine 2,3-dioxygenase (IDO) in APCs and tumor cells, which results in the formation of immunosuppressive TME. In this research, we report the assemblable immune-modulating suspension (AIMS) consisting of TLR 7/8 agonist and IDO inhibitor, which was designed to down-regulate the immune-suppressive factors (TGF-β, IL-10, myeloid-derived suppressor cells, regulatory T cells) and to increase the infiltration of cytotoxic T lymphocytes. The best combination of immune-modulating agents in AIMS, we called supra-adjuvant, was selected by screening possible combinations of commercialized TLR 7/8 agonists and IDO inhibitors based on the ratio of pro- and anti-inflammatory cytokines. Paclitaxel was also introduced into AIMS to induce immunogenic cell death (ICD) and in situ vaccination efficacy with TLR 7/8 agonist at the tumor bed. Local administration of AIMS increased infiltrated T cells in both local and distant tumors, and inhibited the metastasis of tumors to lung significantly. AIMS also reshaped the TME from ‘cold tumor' to ‘hot tumor' successfully, and increased the responsive rate of immune checkpoint blockade therapy (ICBT) significantly. Taken together, the AIMS composed of supra-adjuvant and ICD-inducer is expected to be used as a platform for the re-programming of immunosuppressive TME and the induction of synergistic cancer immunotherapy with ICBT. Citation Format: Seung Mo Jin, Sang Nam Lee, Yong Taik Lim. Reprogramming of immunosuppressive tumor microenvironments by multifunctional nanoemulsion and enhance immune checkpoint blockade therapy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1598.

Synergistic cancer immunotherapy combines MVA-CD40L induced innate and adaptive immunity with tumor targeting antibodies

Virus-based vaccines and appropriate costimulation potently enhance antigen-specific T cell immunity against cancer. Here we report the use of recombinant modified vaccinia virus Ankara (rMVA) encoding costimulatory CD40L against solid tumors. Therapeutic treatment with rMVA-CD40L-expressing tumor-associated antigens results in the control of established tumors. The expansion of tumor-specific cytotoxic CD8+ T cells is essential for the therapeutic antitumor effects. Strikingly, rMVA-CD40L also induces strong natural killer (NK) cell activation and expansion. Moreover, the combination of rMVA-CD40L and tumor-targeting antibodies results in increased therapeutic antitumor efficacy relying on the presence of Fc receptor and NK cells. We describe a translationally relevant therapeutic synergy between systemic viral vaccination and CD40L costimulation. We show strengthened antitumor immune responses when both rMVA-CD40L-induced innate and adaptive immune mechanisms are exploited by combination with tumor-targeting antibodies. This immunotherapeutic approach could translate into clinical cancer therapies where tumor-targeting antibodies are employed.

A synergistic cancer immunotherapy nano-system for preventing tumor growth

Immunotherapy has become a promising therapy in cancer treatment. Both photothermal therapy (PTT) and genotoxic chemotherapy can trigger immune responses. On this subject, a synergistic cancer immunotherapy nano-system was developed for treating primary and distant tumors. This long-time, synergistic therapeutic system consisted of two parts: one was indocyanine green (ICG) and sepantronium bromide (YM155) co-loaded mesoporous silica nanoparticles (MSNs) for PTT and genotoxic chemotherapy, which could effectively destroy primary tumors and thus cause exposure of tumor antigens for cancer immunotherapy. The other was silica nanoparticles (nSiO2) coated with magnetic nanoparticles (MNP) and conjugated with anti-CD47 antibody (anti-CD47), which demonstrated a strong antitumor immune effect of distant tumors after PTT and genotoxic chemotherapy. In vitro and vivo results proved that this synergistic system could efficiently inhibit primary and distant tumor growth. We expected that this paper may develop a promising strategy to prevent tumor growth for basic and clinical research.

Abstract 1468: Synergistic cancer immunotherapy combination of MVA-CD40L with tumor targeting antibodies or checkpoint blockade to achieve strong antitumor immune responses against large, established tumors

Abstract Virus-based vaccines and appropriate costimulation potently enhance antigen-specific T cell immunity against cancer. In the present study, we exploit both innate and adaptive immune responses triggered by recombinant modified vaccinia virus Ankara (rMVA) encoding costimulatory CD40L against large, established tumors in different combinatory settings. Therapeutic treatment with rMVA-CD40L resulted in the control or eradication of solid tumors in several unrelated tumor models. The expansion of non-exhausted, tumor-specific cytotoxic CD8+ T cells was essential for the therapeutic activity and was partially dependent on CD8α+ cross-presenting dendritic cells. Combination of rMVA-CD40L with PD-1 checkpoint blockade further enhanced the therapeutic activity of MVA virotherapy in colorectal carcinoma. In addition, rMVA-CD40L combined with antibodies targeting Tumor-Associated Antigens (TAA) resulted in increased therapeutic antitumor efficacy against two unrelated tumor models. We describe a translationally relevant therapeutic synergy between viral vaccination and CD40L costimulation. We show strengthened antitumor immune responses when both rMVA-CD40L-induced innate and adaptive immune mechanisms are exploited by combining immunotherapeutic regimes, such as checkpoint blockade and TAA targeting antibodies. This novel immunotherapeutic approach could translate into clinical cancer therapies where ADCC competent TAA targeting antibodies PD-1 checkpoint blockade are employed. Citation Format: Jose Medina-Echeverz, Maria Hinterberger, Raphael Giessel, Barbara Bathke, Ronny Kassub, Giovanna Fiore, Paul Chaplin, Hubertus Hochrein, Henning Lauterbach. Synergistic cancer immunotherapy combination of MVA-CD40L with tumor targeting antibodies or checkpoint blockade to achieve strong antitumor immune responses against large, established tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1468.

Temporally Programmed CD8α+ DC Activation Enhances Combination Cancer Immunotherapy

Numerous synergistic cancer immunotherapy combinations have been identified, but the effects of relativedose timing are rarely considered. In established syngeneic mouse tumor models, we found that staggering interferon-α (IFNα) administration after, rather than before or simultaneously with, serum-persistentinterleukin-2 (IL-2) and tumor-specific antibody significantly increased long-term survival. Successful combination therapy required IFNα-induced activation of cross-presenting CD8α+ dendritic cells (DCs) following the release of antigenic tumor debris by the IL-2- and antibody-mediated immune response. Due to decreased phagocytic ability post-maturation, DCs activated too early captured less antigen and could not effectively prime CD8+ Tcells. Temporally programming DC activation to occur after tumoricidal activity enhanced tumor control by multiple distinct combination immunotherapies, highlighting dose schedule as an underappreciated factor that can profoundly affect the success of multi-component immunotherapies.