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

项目总结 一线化疗是三阴性乳腺癌(TNBC)患者的标准护理。而当 短期缓解是可以实现的，大多数患者因转移而死于复发。微转移 包括少量休眠的播散性肿瘤细胞(DTCs)，这些细胞存活于 静止期/衰老期，然后才开始“爆炸性”转移性生长。标准的化疗是 对分裂缓慢的ddtc完全无效。相比之下，癌症免疫治疗是基于 免疫识别和靶向杀伤肿瘤细胞的前提，从而具有控制肿瘤细胞的潜在能力 处于休眠状态的转移癌细胞。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与积聚的 功能失调的抗原提呈细胞(APC)。更改TME的有效方法是重新编程这些 抑制性APC转化为适当激活的APC，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，利用转移性TME的独特生理特征， 允许系统地给药纳米粒，以在TME内实现强大的免疫刺激。第一，要 驱动可持续的抗肿瘤免疫反应，我们利用两条协同的天然免疫途径，通过共同 运送两种免疫激动剂。免疫-NP与干扰素刺激物激动剂共负载 基因(刺痛)途径和Toll样受体4(TLR4)激动剂，它们协同产生高水平的 I型干扰素β。双激动剂NP保证两种激动剂被相同的APC摄取，这 引发了功能协同效应。其次，免疫NP有助于熟练地将每种激动剂呈现给 APC在细胞内的适当位置。第三，免疫-NP是为全身给药而设计的 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。作为一名 结果，肿瘤部位产生高水平的干扰素β，导致活化的aPC和NK细胞，从而 从而推动额外免疫细胞的招募以及肿瘤反应性的激活 细胞毒CD8+T细胞。任何与免疫NP相关的毒性都是最小和可逆的。我们的中央 假设免疫-NP的双激动剂货物(STING和TLR4激动剂)靶向于 转移的血管周围区域会产生强烈的干扰素β驱动的抗肿瘤免疫反应。 目的1：优化高效靶向转移性TME的免疫NP设计 以STING/TLR4激动剂的比例提供双激动剂货物，以实现最佳的功能协同。 目的2：评价免疫纳米粒的短期和长期安全性，并探讨其作用机制。 抗肿瘤免疫反应与免疫-NP给药剂量和频率有关。 目的3：评价免疫-NP单药治疗和联合免疫治疗的疗效 转移性肿瘤小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.