Activation of Intratumoral pDCs by Tumor Self-DNA Coupled with Anti-microbial

肿瘤具有潜在的免疫原性；然而，它们不能自发地诱导免疫反应。 能够排斥肿瘤。一个主要原因是肿瘤的微环境缺乏足够的先天条件。 启动强大的适应性抗肿瘤免疫所需的免疫激活。 浆细胞样树突状细胞(Pdc)是一种高度专门化的树突状细胞亚群。 核酸通过细胞内的Toll样受体。在病毒感染期间，PDC在受感染的组织中积累 并被病毒核酸激活以产生大量的I型IFN并产生保护性的 通过激活髓系树突状细胞、T细胞和NK细胞来免疫病毒。 肿瘤也含有pDC，但不提供激活pDC的分子信号。虽然肿瘤 含有高浓度的自身DMA在细胞外环境中释放的结果是增加 周转和肿瘤细胞死亡，很明显，pDC虽然被病毒核酸激活，但通常不 能够感觉到肿瘤衍生的DMA，因此无法启动强大的先天免疫反应。我们 最近发现，当PDC与内源性DNA结合时，实际上可以感知和响应自我DMA 名为LL37的多肽。IL-37可以与死亡细胞释放的自身DMA片段结合形成聚集体，并 被运送到并保留在pDC早期内涵体中的浓缩结构。在这些 在细胞内，LL37/DNA可以与TLR9相互作用，以类似的方式触发I型干扰素的产生 致病毒式DMA。 由于肿瘤释放大量的自身DNA并含有pDC，但不表达LL37，我们的 假设外源LL37可用于靶向肿瘤来源的自身DMA并将其转化为 “危险信号”，触发PDC激活和I型干扰素在肿瘤部位的产生。这将导致 T细胞介导的抗肿瘤免疫机制与抗病毒免疫反应的机制相同 都是被诱导的。 特异性目标1将确定LL37是否能够将濒死的肿瘤细胞释放的自身DMA从 免疫惰性转化为PDC激活的触发器，以产生I型IFN。《特定目标2》将评估 LL37与正在死亡的肿瘤细胞体外混合和体内注射作为疫苗能否诱导有效T细胞 细胞介导的抗肿瘤免疫。特定目标3将评估正在死亡的肿瘤细胞是否释放自身DMA 可以通过瘤内注射或全身注射LL37来靶向诱导天然免疫 在肿瘤部位的激活，导致有效的抗肿瘤免疫。这些研究可能会导致设计 未来使用LL37对患有弥漫转移性疾病的癌症患者进行临床试验。

Tumors are potentially immunogenic; however, they fail to spontaneously induce an immune response capable of rejecting the tumor. A major reason is that the tumor microenvironment lacks adequate innate immune activation required to initiate strong adaptive anti-tumor immunity. Plasmacytoid dendritic cells (pDC) comprise a dendritic cell subset highly specialized in sensing microbial nucleic acids via intracellular Toll-like receptors. During viral infection, pDC accumulate in infected tissues and are activated by viral nucleic acids to produce large amounts of type I IFNs and generate protective immunity against the virus through activation of myeloid DCs, T cells, and NK cells. Tumors also contain pDCs, but do not provide the molecular signals to activate pDCs. Although tumors contain high concentrations of self-DMA released in the extracellular environment as a result of the increased turnover and tumor cell death, it is clear that pDCs, while activated by viral nucleic acids, are normally not able to sense tumor-derived DMA and are thereby unable to initiate a strong innate immune response. We recently found that pDC can, in fact, sense and respond to self-DMA when combined with an endogenous peptide called LL37. LL-37 can bind self-DMA fragments released by dying cells to form aggregates and condensed structures that are delivered to and retained within early endosomes of pDCs. In these intracellular compartments, LL37/DNA can interact with TLR9 to trigger robust type I IFN production similarly to viral DMA. Because tumors release large amounts of self-DMA and contain pDCs but do not express LL37, our hypothesis is that exogenous LL37 can be used to target tumor-derived self-DMA and convert it into a "danger signal" that triggers pDC activation and type I IFN production at the tumor site. This will then induce T-cell mediated immunity against the tumor by the same mechanism by which anti-viral immune responses are induced. Specific Aim 1 will determine whether LL37 can convert self-DMA released by dying tumor cells from being immunologically inert into a trigger of pDC activation to produce type I IFNs. Specific Aim 2 will evaluate whether LL37 mixed with dying tumor cells ex-vivo and injected in-vivo as a vaccine can induce effective T cell-mediated anti-tumor immunity. Specific Aim 3 will assess whether dying tumor cells releasing self-DMA can be targeted by intratumoral injection or systemic administration of LL37 to induce innate immune activation at the tumor site leading to effective anti-tumor immunity. These studies may lead to the design of future clinical trials utilizing LL37 in cancer patients with diffusely metastatic disease.