Novel strategy combined with targeted radiation therapy unleashes potent antitumor immunity in HPV + head and neck cancer

项目总结/摘要 HPV相关的头颈癌（HNC）的巨大公共卫生负担已经造成了巨大的经济损失。 对具有降低的治疗发病率和改善的长期存活率的新型、广泛有效的疗法的需求。 虽然在HPV+癌症中靶向HPV抗原可能是直观的，但这些策略尚未证明清楚。 治疗效果，可能是由于新抗原特异性细胞毒性T细胞免疫的重要性， 长期控制所有癌症，包括病毒相关癌症（1）。设计一个现成的，广泛有效的 治疗策略可以很容易地与标准化放疗结合， 在HPV相关HNC中增强HPV和新抗原特异性CD 8 + T细胞免疫可以证明 广泛有效。肿瘤特异性CD 8 + T细胞免疫的产生需要有效的抗原呈递 由于肿瘤细胞不能有效地呈递相关的CD 8 + T细胞表位，小鼠CD 103 + 和CD 8a + DC（cDC 1）以其处理外源性抗原的能力而闻名，并有效地交叉呈递给 CD 8 + T细胞。因此，增强交叉呈递DC亚群的创新策略可以有力地 诱导HPV和新抗原特异性免疫，并在治疗HPV中具有巨大的治疗潜力， 相关HNC FMS样酪氨酸激酶3配体（Flt 3L）是一种扩增和分化DC的细胞因子 Flt 3L是小鼠cDC 1的前体，但由于其半衰期短和全球性，Flt 3L的治疗潜力有限。 体内分布我们已经通过产生白蛋白的遗传融合物克服了Flt 3L的所述问题， (Alb)转化为Flt 3L，命名为白蛋白-Flt 3L（Alb-Flt 3L）。由于新生儿Fc受体（FcRn），Alb具有较长的半衰期- 介导的转细胞再循环，并表现出运输到LN作为血清蛋白。小说 免疫球蛋白Alb-Flt 3L融合蛋白在LN中表现出增加的半衰期和选择性积累， 与天然Flt 3L相比的肿瘤。Alb-Flt 3L能够在体内扩增交叉呈递DC群体， 单次注射。Alb-Flt 3L+靶向放射治疗（RT）释放肿瘤抗原并增强肿瘤细胞增殖 免疫原性能够控制结肠腺癌MC 38肿瘤进展并延长存活 产鼠令人印象深刻的是，Alb-Flt 3L + RT诱导自发的肿瘤新抗原特异性T细胞应答， 除了在PANC 02模型中作为单药的疗效外。在该提案中，Alb-Flt 3L促进HPV-1的能力被认为是一种新的靶点。 和通过交叉呈递DC的扩增的新抗原特异性细胞毒性T细胞抗肿瘤免疫， 随后将研究多种HPV相关HNC模型中的肿瘤控制。HPV和新抗原 将使用四聚体和TCR测序方法评价特异性CD 8 + T细胞应答。的 Alb-Flt 3L介导其免疫刺激功能的机制也将使用 合适的缺陷小鼠模型。成功完成此提案将产生有价值的临床前 和关于Alb-Flt 3L的治疗潜力的机制数据， 作为治疗HPV相关HNC以及许多其他类型的癌症的通用策略的有效性。

Project Summary/Abstract The overwhelming public health burden of HPV-associated head and neck cancer (HNC) has created great demand for novel, broadly effective therapies with reduced treatment morbidity and improved long term survival. While targeting HPV antigens in HPV+ cancers may be intuitive, these strategies have not demonstrated clear treatment efficacy, potentially due to the importance of neoantigen-specific cytotoxic T cell immunity in the long- term control of all cancers, including viral-associated cancer (1). Devising an off-the-shelf, broadly effective therapeutic strategy that can easily be combined with standard-of-care chemoradiation and is capable of potentiating both HPV- and neoantigen-specific CD8+ T cell immunity in HPV-associated HNC could prove widely efficacious. The generation of tumor-specific CD8+ T cell immunity requires potent antigen presentation by dendritic cells (DCs) since tumor cells do not efficiently present relevant CD8+ T cell epitopes. Murine CD103+ and CD8a+ DCs (cDC1s) are known for their ability to process exogenous antigen and potently cross-present to CD8+ T cells. Because of this, innovative strategies to enhance cross-presenting DC subsets could robustly induce HPV- and neoantigen-specific immunity and have great therapeutic potential in the treatment of HPV- associated HNC. FMS-like tyrosine kinase 3 ligand (Flt3L) is a cytokine that expands and differentiates DC precursors to murine cDC1s, but therapeutic potential of Flt3L is limited because of its short half-life and global distribution in vivo. We have overcome the described issues of Flt3L by generating a genetic fusion of Albumin (Alb) to Flt3L, named Albumin-Flt3L (Alb-Flt3L). Alb has a long half-life due to neonatal Fc receptor (FcRn)- mediated transcytolic recycling, and exhibits trafficking to the LNs as a serum protein. The novel immunotherapeutic Alb-Flt3L fusion protein exhibits increased half-life and selective accumulation in LN and tumor compared to native Flt3L. Alb-Flt3L is able to expand cross-presenting DC populations in vivo following a single injection. Alb-Flt3L + targeted radiation therapy (RT) to release tumor antigens and enhance tumor immunogenicity is able to control tumor progression and extend survival of colon adenocarcinoma MC38 tumor bearing mice. Impressively, Alb-Flt3L + RT induced spontaneous tumor neoantigen-specific T cell responses, in addition to efficacy as a single agent in PANC02 model. In this proposal, the ability of Alb-Flt3L to promote HPV- and neoantigen-specific cytotoxic T cell antitumor immunity through the expansion of cross-presenting DCs and subsequent tumor control in multiple HPV-associated HNC models will be investigated. HPV- and neoantigen- specific CD8+ T cell responses will be evaluated using tetramer and TCR sequencing approaches. The mechanism by which Alb-Flt3L mediates its immunostimulatory function will also be interrogated using appropriate deficient mouse models. Successful completion of this proposal will generate valuable preclinical and mechanistic data regarding the therapeutic potential of Alb-Flt3L, a novel immunotherapeutic with potential efficacy as a universal strategy to treat HPV-associated HNC as well as many other types of cancer.