Generation of tumor specific immunity in canine osteosarcoma through dendritic cell hyperactivation

项目摘要 尽管在治疗策略上有了实质性的改进，但在小鼠中产生强大的抗肿瘤免疫应答仍然是一个挑战。 具有较低体细胞突变负荷的人类癌症仍然是一个重大挑战。最近的数据显示， 在这个过程中，树突状细胞（DCs）是一个关键的参与者，它不能有效地引发有效和持久的T细胞应答 除非他们进入了一种特殊的超激活状态在这种情况下，发展中国家表现出增强的迁移， 局部淋巴结（LN）和持续分泌IL-1β，一种对记忆T细胞形成至关重要的细胞因子。在 小鼠肿瘤模型，用全肿瘤裂解物加上由TLR 7/8激动剂组成的佐剂接种 R848（瑞喹莫特）与独特的分离的溶血磷脂酰胆碱（22：0 Lyso PC）组合促进DC 超活化、抗原特异性CD 8 + T细胞的扩增和肿瘤的强烈排斥。虽然这些发现 是令人鼓舞的，并表明识别特定的新抗原是不必要的，以引发和扩大 细胞毒性T细胞（CTL）池，验证和优化这种方法需要使用一个模型 系统，更接近地概括人类癌症的免疫景观。因此，目的 这项建议的一个重要方面是使用自发性犬癌，特别是骨肉瘤（OS），作为桥接 动物模型，以验证DC超活化作为产生 强大的抗肿瘤免疫力。在本申请中要测试的中心假设是， 用WTL衍生的新抗原超活化DC将扩增多样化的和肿瘤特异性的CTL群体 能够消除狗中原发性肿瘤切除后残留的显微镜下转移性OS肿瘤细胞 （截肢）。我们进一步预测，将DC超活化/WTL与新的肿瘤微环境相结合， (TME)由toceranib/losartan/ladarixin组成的预处理方案将提高客观缓解率 发生肉眼可见肺转移的狗。为了实现这一目标，我们将进行一项前瞻性随机 在OS犬中联合截肢和标准治疗卡铂化疗与辅助治疗的临床试验 单独或佐剂+WTL。发生肺转移的犬随后将接受TME预处理 方案与佐剂+WTL组合。将从犬中收集组织样本和血液的生物样本库 包括匹配的原发性/转移性肿瘤和相关LN，全血，血浆， PBMC、无细胞DNA和来自疫苗引流淋巴结的样品。这些将用于执行一组 设计用于表征免疫微环境和肿瘤基因组的互补测定， 复发/耐药过程，证明一种新的新抗原预测管道，并评估抗原特异性T细胞 细胞反应。一个优秀的团队，在临床试验、翻译和临床试验方面具有互补的专业知识。 肿瘤学，比较基因组学和免疫肿瘤学已经组装，以确保所述的里程碑是 办妥了一批这得益于我们与行业合作伙伴Corner Therapeutics的动态合作， 致力于支持这项工作，以促进优化和成功转化为人类患者。

PROJECT SUMMARY Despite substantial improvements in therapeutic strategies, generating robust anti-tumor immune responses in human cancers with a lower somatic mutation burden remains a substantial challenge. Recent data indicate that a critical player in this process, dendritic cells (DCs), fail to effectively elicit efficient and durable T cell responses unless they have entered a unique state of hyperactivation. In this setting, DCs exhibit enhanced migration to local lymph nodes (LNs) and sustained secretion of IL-1β, a cytokine critical for memory T cell formation. In mouse tumor models, vaccination with whole tumor lysate plus an adjuvant consisting of the TLR 7/8 agonist R848 (resiquimod) in combination with a unique isolated lysophosphatidylcholine (22:0 Lyso PC) promotes DC hyperactivation, expansion of antigen specific CD8+ T cells, and robust rejection of tumors. While these findings are encouraging and suggest that identification of specific neoantigens is not necessary to prime and expand a pool of cytotoxic T cells (CTLs), validation and optimization of this approach necessitates the use of a model system that more closely recapitulates human cancers with respect to immune landscape. As such, the purpose of this proposal is to use spontaneous canine cancer, specifically osteosarcoma (OS), as a bridging animal model to validate the utility of DC hyperactivation as a foundational element for generation of robust anti-tumor immunity. The central hypothesis to be tested in this application is that combining hyperactivation of DCs with WTL derived neoantigen will expand a diverse and tumor-specific population of CTLs capable of eliminating residual microscopic metastatic OS tumor cells in dogs following primary tumor removal (amputation). We further predict, that combining DC hyperactivation/WTL with a novel tumor microenvironment (TME) conditioning regimen consisting of toceranib/losartan/ladarixin will enhance the objective response rate in dogs that develop macroscopic lung metastasis. To accomplish this, we will conduct a prospective randomized clinical trial in dogs with OS combining amputation and standard of care carboplatin chemotherapy with adjuvant alone or adjuvant+WTL. Dogs that develop lung metastasis will then be treated with the TME conditioning regimen in combination with adjuvant+WTL. A biobank of tissue samples and blood will be collected from dogs enrolled in these trials including matched primary/metastatic tumors and associated LNs, whole blood, plasma, PBMCs, cell-free DNA, and samples from the vaccine draining LNs. These will be used to perform a set of complementary assays designed to characterize the immune microenvironment and tumor genome over the course of relapse/resistance, credential a novel neoantigen prediction pipeline, and evaluate antigen specific T cell responses. An outstanding team with complementary sets of expertise across clinical trials, translational oncology, comparative genomics, and immuno-oncology has been assembled to ensure stated milestones are achieved. This is bolstered by a dynamic collaboration with our industry partner, Corner Therapeutics, which is committed to supporting this work to facilitate optimization and successful translation into human patients.