Combination immunotherapy of glioblastoma with dendritic cell cancer vaccines,anti-PD-1 and poly I:C

Glioblastoma(GBM)is a lethal cancer with limited therapeutic options.Dendritic cell(DC)-based cancer vaccines provide a promising approach for GBM treatment.Clinical studies suggest that other immunotherapeutic agents may be combined with DC vaccines to further enhance antitumor activity.Here,we report a GBM case with combination immunotherapy consisting of DC vaccines,anti-programmed death-1(anti-PD-1)and poly I:C as well as the chemotherapeutic agent cyclophosphamide that was integrated with standard chemoradiation therapy,and the patient remained disease-free for 69 months.The patient received DC vaccines loaded with multiple forms of tumor antigens,including mRNA-tumor associated antigens(TAA),mRNA-neoantigens,and hypochlorous acid(HOCl)-oxidized tumor lysates.Furthermore,mRNA-TAAs were modified with a novel TriVac technology that fuses TAAs with a destabilization domain and inserts TAAs into full-length lysosomal associated membrane protein-1 to enhance major histocompatibility complex(MHC)class I and II antigen presentation.The treatment consisted of 42 DC cancer vaccine infusions,26 anti-PD-1 antibody nivolumab administrations and 126 poly I:C injections for DC infusions.The patient also received 28 doses of cyclophosphamide for depletion of regulatory T cells.No immunotherapy-related adverse events were observed during the treatment.Robust antitumor CD4t and CD8t T-cell responses were detected.The patient remains free of disease progression.This is the first case report on the combination of the above three agents to treat glioblastoma patients.Our results suggest that integrated combination immunotherapy is safe and feasible for long-term treatment in this patient.A large-scale trial to validate these findings is warranted.

Differential centrifugation enhances the anti-tumor immune effect of tumor lysate-pulsed dendritic cell vaccine against glioblastoma

Objective This study aimed to improve the antitumor immunocompetence of a tumor lysate-pulsed dendritic cell(DC)vaccine through differential centrifugation and provide a theoretical basis for its clinical application in glioblastoma.Methods Peripheral blood mononuclear cells were extracted using Ficoll-Paque PLUS and induced into mature DCs in vitro with a cytokine cocktail.The modified tumor lysate was generated by differential centrifugation.The maturity markers of DCs in each group,namely the modified tumor lysate,tumor lysate,and negative and positive control groups,were assessed using flow cytometry.Furthermore,their ability to stimulate lymphocyte proliferation and in vitro antitumor effects were assessed using Cell Trace TM CFSE.IFN-γsecretion levels were measured with ELISA.Intracellular reactive oxygen species were measured using 2’,7’-dichlorofluorescein diacetate(DCFDA)staining.The results were statistically analyzed using an unpaired Student’s t-test and were considered significant at P<0.05.Results Compared with tumor lysate-pulsed DCs,modified tumor lysate-pulsed DCs had a higher expression of maturity markers:CD1a(7.38±0.53%vs.4.47±0.75%)and CD83(19.81±4.09%vs.9.64±1.50%),were better capable of stimulating lymphocyte proliferation[proliferation index(PI):8.54±0.16 vs.7.35±0.05],secreting IFN-γ,and inducing stronger in-vitro cytotoxic T lymphocyte(CTL)cytotoxicity against glioblastoma cells.In addition,we found that the level of ROS in modified tumor lysate-pulsed DCs was lower than that in tumor lysate-pulsed DCs.Conclusion Differential centrifugation of tumor lysates can improve the antitumor immunocompetence of DC vaccines,and reactive oxygen species may be the key to affecting DC function in the whole tumor lysate.

The TLR7 agonists imiquimod and gardiquimod improve DC-based immunotherapy for melanoma in mice

Toll-like receptors(TLRs)are a family of highly conserved germline-encoded pattern-recognition receptors that are essential for host immune responses.TLR ligands represent a promising class of immunotherapeutics or vaccine adjuvants with the potential to generate an effective antitumor immune response.The TLR7/8 agonists have aroused interest because they not only activate antigen-presenting cells but also promote activation of T and natural killer(NK)cells.However,the exact mechanism by which stimulation of these TLRs promotes immune responses remains unclear,and different TLR7/8 agonists have been found to induce different responses.In this study,we demonstrate that both gardiquimod and imiquimod promote the proliferation of murine splenocytes,stimulate the activation of splenic T,NK and natural killer T(NKT)cells,increase the cytolytic activity of splenocytes against B16 and MCA-38 tumor cell lines,and enhance the expression of costimulatory molecules and IL-12 by macrophages and bone marrow-derived dendritic cells(DCs).In a murine model,both agonists improved the antitumor effects of tumor lysate-loaded DCs,resulting in delayed growth of subcutaneous B16 melanoma tumors and suppression of pulmonary metastasis.Further,we found that gardiquimod demonstrated more potent antitumor activity than imiquimod.These results suggest that TLR7/8 agonists may serve as potent innate and adaptive immune response modifiers in tumor therapy.More importantly,they can be used as vaccine adjuvants to potentiate the efficiency of DC-based tumor immunotherapy.

NIR-Ⅱprobe modified by poly(L-lysine)with efficient ovalbumin delivery for dendritic cell tracking

Dendritic cell(DC)vaccine is an effective strategy for cancer immunotherapy by carrying antigen into DCs and migrating these DCs to drain lymph nodes after inoculation.In this article,second near-infrared window(NIR-II)fluorescent nanoparticles have been used to uptake antigen and activate DCs.Ovalbumin(OVA),an antigen for immunization,can be loaded on the surface of these NIR-II fluorescent nanoparticles via electrostatic interaction by virtue of their functionalized poly(L-lysine)(PLL),which exhibits biocompatibility and strong selective interaction with OVA.In addition,these antigen-loaded complexes can efficiently be engulfed by immature DCs to induce DC maturation and cytokine secretion.After subcutaneous injection,highly sensitive NIR-II fluorescence signal from nanoparticles indicates that nanoparticle-labeled DCs can successfully migrate into lymph nodes in vivo,showing great promise in immunotherapy against cancer.

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.