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

项目摘要/摘要 人类乳头状瘤病毒相关性头颈癌(HNC)给公众造成了巨大的健康负担 对新的、广泛有效的治疗方法的需求，以降低治疗发病率和提高长期存活率。 虽然在HPV阳性的癌症中靶向HPV抗原可能是直观的，但这些策略尚未证明是明确的 治疗效果，可能是由于新抗原特异性细胞毒T细胞免疫在长期- 所有癌症的长期控制，包括病毒相关性癌症(1)。设计一种现成的、广泛有效的 治疗策略可以很容易地与标准护理放化疗相结合，并能够 在HPV相关的HNC中增强HPV和新抗原特异性CD8+T细胞免疫可以证明 非常有效。肿瘤特异性CD8+T细胞免疫的产生需要强有力的抗原提呈 由于肿瘤细胞不能有效地呈递相关的CD8+T细胞表位，因此可通过树突状细胞(DC)进行免疫调节。小鼠CD103+ 和CD8a+DC(CD8a+DC)以其处理外源抗原的能力而闻名，并有效地交叉呈现给 CD8+T细胞。正因为如此，增强交叉呈现DC子集的创新策略可以很好地实现 诱导HPV和新抗原特异性免疫，在治疗HPV方面具有很大的治疗潜力 关联的HNC。FMS样酪氨酸激酶3配体(Flt3L)是一种扩增和分化DC的细胞因子 小鼠CDC1s的前体，但Flt3L的治疗潜力有限，因为它的半衰期很短，而且是全球性的 体内分布。我们通过产生白蛋白的基因融合克服了Flt3L的上述问题 (Alb)到Flt3L，命名为白蛋白-Flt3L(Alb-Flt3L)。由于新生儿Fc受体(FcRN)，白蛋白有很长的半衰期- 介导的跨细胞循环，并以血清蛋白的形式运输到LNS。这部小说 免疫治疗Alb-Flt3L融合蛋白在LN和LN中的半衰期和选择性蓄积增加 肿瘤与天然Flt3L的比较。Alb-Flt3L能够在体内扩大交叉呈递的DC群体 单次注射。Alb-Flt3L+靶向放射治疗(RT)释放肿瘤抗原增强肿瘤 免疫原性可控制结肠腺癌MC38肿瘤进展并延长生存期 生老鼠。令人印象深刻的是，Alb-Flt3L+RT诱导了自发的肿瘤新抗原特异性T细胞反应，在 在PANC02模型中，作为单一药物的有效性。在这项提议中，Alb-Flt3L促进HPV- 和新抗原特异性的细胞毒性T细胞通过扩增交叉递呈的DC和 后续的肿瘤控制将在多个HPV相关的HNC模型中进行调查。人乳头瘤病毒和新抗原- 将使用四聚体和TCR测序方法评估特定的CD8+T细胞反应。这个 Alb-Flt3L介导其免疫刺激功能的机制也将被用 适当建立缺血小鼠模型。成功完成这项提议将产生有价值的临床前 和关于Alb-Flt3L治疗潜力的机制数据，Alb-Flt3L是一种潜在的新型免疫疗法 作为一种治疗HPV相关HNC以及许多其他类型癌症的普遍策略。

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.