Project description:Poly I:C is a powerful immune adjuvant as a result of its agonist activities on TLR-3, MDA5 and RIG-I. Intratumoral administration is conceivably safer than systemic delivery and allows concentrate proinflammatory adjuvanticity in the tumor microenvironment and tumor-draining lymphoid tissue. BO-112 is a nanoplexed formulation of Poly I:C complexed with polyethylenimine that causes tumor cell apoptosis showing immunogenic cell death features and that upon intratumoral release results in more prominent tumor infiltration by T lymphocytes. Intratumoral treatment of subcutaneous tumors derived from MC38, 4T1 and B16F10 with BO-112 leads to remarkable local disease control mediated by CD8+ T lymphocytes, as concluded from selective depletion experiments. Some degree of control of non-injected tumor lesions upon BO-112 intratumoral treatment was found in mice bearing bilateral B16OVA melanomas, that was enhanced when co-treated with systemic anti-CD137 and anti-PD-L1 immunomodulatory mAbs. More abundant CD8+ T lymphocytes were found in tumor-draining lymph nodes and in the tumor microenvironment following intratumoral treatment with BO-112. Enhanced numbers of tumor-specific CTLs recognizing melanosomal antigens and ovalbumin were readily detected among them. Genome-wide transcriptome analyses of injected tumor lesions were consistent with a marked upregulation of the type-I interferon pathway. Intratumorally delivered BO-112 is being tested in cancer patients (NCT02828098) and our results in mice suggest prominent anti-tumor local control through its proimmune effects. Intratumoral administration of BO-112, a nanoplexed form of PolyI:C, triggers an efficacious antitumor response in different tumor models as a consequence of proimmflamatory activity and its direct effects in tumor cells. BO-112 local administration induces direct tumor cell death by apoptosis, showing signs of immunogenic cell death, and a strong release of IFNα/β and other proinflammatory mediators. As a result, a tumor-specific CD8+ immune response is mounted or augmented to the point of controlling tumor progression both in the locally injected lesion and to some extent on distantly implanted tumor nodules

Project description:Background Lymphocytic choriomeningitis virus (LCMV) belongs to the Arenavirus family known for inducing strong cytotoxic T-cell responses in both mice and humans. LCMV has been engineered for the development of anti-tumor vaccines, currently undergoing evaluation in phase I/II clinical trials. Initial findings have demonstrated safety and an exceptional ability to induce and expand tumor-specific T lymphocytes. Combination strategies to maximize the anti-tumor effectiveness of LCMV-based vaccines are required. Methods We assessed the anti-tumor therapeutic effects of intratumoral administration of polyinosinic:polycytidylic acid (poly(I:C)) and systemic vaccination using an LCMV-vector expressing non-oncogenic versions of the E6 and E7 antigens of human papillomavirus 16 (artLCMV-E7E6) in a bilateral model engrafting TC-1/A9 cells. This cell line, derived from the parental TC-1, exhibits low MHC class I expression and is highly immune-resistant. The mechanisms underlying the combination's efficacy were investigated through bulk RNAseq, flow cytometry analyses of the tumor microenvironment, selective depletions using antibodies and clodronate liposomes, Batf3 deficient mice, and in vivo bioluminescence experiments. Finally, we assessed the anti-tumor effectiveness of the combining of LCMV-E6E7 with BO-112, a GMP-grade poly(I:C) formulated in polyethyleneimine, currently under evaluation in clinical trials. Results Intratumoral injection of poly(I:C) enhanced the anti-tumor efficacy of artLCMV-E7E6 in both injected and non-injected tumor lesions. The combined treatment resulted in a significant delay in tumor growth and often complete eradication of several tumor lesions, leading to significantly improved survival compared to monotherapies. While intratumoral administration of poly(I:C) did not impact LCMV vector biodistribution or transgene expression, it significantly modified leukocyte infiltrates within the tumor microenvironment and amplified systemic efficacy through proinflammatory cytokines/chemokines such as CCL3, CCL5, CXCL10, TNF, IFNα, and IL12p70. Upregulation of MHC on tumor cells and a reconfiguration of the gene expression programs related to tumor vasculature, leukocyte migration, and the activation profile of tumor-infiltrating CD8+ T lymphocytes were observed. Indeed, the anti-tumor effect relied on the functions of CD8+ T lymphocytes and macrophages. The synergistic efficacy of the combination was further confirmed when BO-112 was included. Conclusion Intratumoral injection of poly(I:C) sensitizes MHClow tumors to the anti-tumor effects of artLCMV-E7E6, resulting in a potent therapeutic synergy

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Immunotherapeutic effects of intratumoral nanoplexed Poly I:C (B16-OVA cell line)

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