Targeted immuno-nanoparticles for directing antitumor immune response against breast cancer metastasis

项目摘要 一线化疗是三阴性乳腺癌（TNBC）患者的标准治疗。而 短期反应是可实现的，大多数患者由于转移而死于复发。微转移 包括一小群休眠的播散性肿瘤细胞（dDTC），其在肿瘤细胞中存活。 静止/衰老状态，然后开始其“爆炸性”转移性生长。标准化疗是 对缓慢分裂的dDTC完全无效。相比之下，癌症免疫疗法是基于 免疫识别和靶向杀伤肿瘤细胞的前提下，从而具有很好的控制能力， 休眠的转移癌细胞然而，免疫治疗的一个主要障碍是克服深刻的 肿瘤微环境（TME）内的免疫抑制。TME与以下物质的积累有关： 功能失调的抗原呈递细胞（APC）。改变TME的有效方法是重新编程这些细胞， 抑制性APC转化为适当活化的APC，其刺激肿瘤抗原特异性T细胞。我们设计了一个 免疫刺激纳米颗粒，其利用转移性TME的独特生理特征， 允许纳米颗粒的全身递送以在TME内实现稳健的免疫刺激。一是 驱动可持续的抗肿瘤免疫反应，我们利用两个协同先天免疫途径， 传递两种免疫激动剂免疫NP与干扰素刺激剂的激动剂共负载 基因（STING）途径和Toll样受体4（TLR 4）激动剂，其协同产生高水平的 I型干扰素（IFN）β。双激动剂NP保证了两种激动剂被相同的APC摄取， 增强功能协同作用。第二，免疫NP促进每种激动剂有效地呈递给靶细胞。 APC的适当细胞内定位。第三，免疫NP被设计用于全身施用 靶向转移的富含APC的血管周围区域，导致主要由APC细胞摄取。作为 结果，肿瘤部位产生的高水平IFNβ导致APC和NK细胞活化， 从而驱动额外免疫细胞的募集以及肿瘤反应性细胞的激活。 细胞毒性CD 8 + T细胞。任何免疫NP相关的毒性都是最小的和可逆的。我们的中央 一种假设是，靶向免疫-NP的双激动剂货物（STING和TLR 4激动剂）是靶向免疫-NP的双激动剂货物（STING和TLR 4激动剂）。 转移的血管周围区域将产生强烈的IFNβ驱动的抗肿瘤免疫应答。 目标1：优化高效靶向转移性TME并介导共表达的免疫NP设计 在一个实施方案中，双激动剂货物以STING/TLR 4激动剂的比率递送以获得最佳的功能协同作用。 目的2：评价免疫NP的短期和长期安全性特征，并表征其作用机制。 与免疫NP给药的剂量和频率相关的抗肿瘤免疫应答。 目的3：评价免疫NP作为单药治疗和与免疫NP联合治疗的疗效。 在转移性TNBC的鼠模型中的检查点抑制剂。

PROJECT SUMMARY First-line chemotherapy is the standard of care for patients with triple-negative breast cancer (TNBC). While short-term response is achievable, most patients succumb to recurrence due to metastasis. Micrometastasis encompasses a small population of dormant disseminated tumor cells (dDTCs) that survive in quiescent/senescent states prior to initiating their ‘explosive’ metastatic outgrowth. Standard chemotherapy is completely ineffective against the slow-dividing dDTCs. In contrast, cancer immunotherapy is based on the premise of immune-recognition and targeted killing of tumor cells, thus possess the promising power to control dormant metastatic cancer cells. However, one major hurdle in immunotherapy is to overcome the profound immunosuppression within the tumor microenvironment (TME). TME is associated with the accumulation of dysfunctional antigen-presenting cells (APCs). An effective approach to alter TME is to reprogram these inhibitory APCs into properly activated APCs that stimulate tumor antigen-specific T cells. We designed an immuno-stimulatory nanoparticle that exploits the unique physiological features of metastatic TME, which allows the systemic delivery of nanoparticles to achieve a robust immunostimulation within the TME. First, to drive a sustainable antitumor immune response, we harness two synergistic innate immune pathways by co- delivering two immune agonists. The immuno-NP is co-loaded with an agonist of the Stimulator of Interferon Genes (STING) pathway and a Toll-like receptor 4 (TLR4) agonist, which synergize to produce high levels of Type I interferon (IFN) β. The dual-agonist NP guarantees uptake of both agonists by the same APC, which elicits functional synergy. Second, the immuno-NP facilitates proficient presentation of each agonist to the appropriate intracellular location of APCs. Third, the immuno-NP is designed for systemic administration targeting the APC-rich perivascular areas of metastasis, leading to uptake predominantly by APC cells. As a result, high levels of IFNβ produced within the tumor site lead to the activation of APC and NK cells that consequently drive the recruitment of additional immune cells as well as the activation of tumor-reactive cytotoxic CD8+ T cells. Any immuno-NP-associated toxicity was minimal and reversible. Our central hypothesis is that the dual-agonist cargo (STING and TLR4 agonists) of the immuno-NP targeted to the perivascular regions of metastasis will produce a strong IFNβ-driven antitumor immune response. Aim 1: Optimize an immuno-NP design that targets the metastatic TME with high efficiency and mediates co- delivery of the dual-agonist cargo at the ratio of STING/TLR4 agonists for optimal functional synergy. Aim 2: Evaluate the short and long-term safety profile of the immuno-NP and characterize the mechanism of antitumor immune responses associated with dosage and frequency of immuno-NP administration. Aim 3: Evaluate the therapeutic efficacy of the immuno-NP as a monotherapy and in combination with immune checkpoint inhibitors in murine models of metastatic TNBC.