Exploring novel strategies for immunoprevention of estrogen receptor negative breast cancer

摘要 2020年，乳腺癌已超过肺癌，成为女性最常被诊断的癌症。 与雌激素受体(ER)阳性乳腺癌相比，ER阴性(ER-)乳腺癌病情更严重 预后差，没有有效的预防策略。在这项研究中，我们将探索新的战略， ER乳腺癌的免疫预防。诱导强大的抗肿瘤免疫预防不良 免疫原性乳腺癌一直是极具挑战性的。活化树枝晶的接合与膨胀 树突状细胞(DC)可以促进广泛而有效的抗肿瘤免疫。然而，某些现有的DC刺激器 (例如，Toll样受体激动剂和刺痛)也会引发不良免疫反应。治疗癌症 在预防方面，必须开发安全有效的方法来提高DC免疫力。为此，我们 对增加DC活性的膳食补充剂进行筛选，并确定天然维生素E(VitE)是刺激物 DC函数。令人兴奋的是，我们发现在免疫治疗期间服用维生素E的乳腺癌患者有一个 与未服用维生素E的患者相比，存活率和治疗反应显著提高， 提示维生素E可增强机体的抗肿瘤免疫功能。的确，全身(口服)给药 和局部注射(与癌症疫苗一起)的维生素E显著延长了无肿瘤的时间 仅对癌症疫苗不起作用的ER-乳腺肿瘤小鼠模型的存活率。这些数据引导我们 假设维生素E的使用通过加强DC激活和抗原递呈，增强 肿瘤疫苗免疫预防ER乳腺癌的研究。我们将测试维生素E是否会增加癌症 疫苗诱导的免疫监视和基因工程预防/延缓肿瘤的起始/进展 (HER2+和基底细胞样亚型)ER乳腺肿瘤小鼠模型及CD34+人源化小鼠 模型(用于预防人类ER-乳腺癌)(Aim1)。作为概念证明，我们将主要使用三重- 抗原(肿瘤相关抗原neu/IGFBP-2/IGF-IR)多肽疫苗(TAVac)自 在ER-乳腺癌小鼠模型中，TAVac已显示出部分延缓肿瘤进展的作用。 重要的是，相应的针对人HER2/IGFBP-2/IGF-IR的DNA疫苗目前处于I/II阶段 预防HER2+和HER2-乳腺癌复发的临床研究获得机械的洞察力 维生素E如何增强抗肿瘤免疫，我们将研究i)维生素E对免疫细胞的整体影响 2)维生素E对DC和T细胞亚群组成、功能的影响 和信号网络；iii)对维生素E增强的免疫预防至关重要的主要免疫表型变化；iv) 维生素E如何促进DC的抗原处理/提呈，以及维生素E是否通过SHP1发挥作用，SHP1是一个关键的 DC检查点(AIM2)。最后，我们将测试新的策略，以进一步提高免疫预防效果 抗ER-乳腺肿瘤(Aim3)。如果成功，我们的策略将很容易在未来的临床试验中得到测试。 用于乳腺癌的免疫预防，特别是对患ER乳腺癌的高危女性。

Summary In 2020, breast cancer has surpassed lung cancer as the most commonly diagnosed cancer in women. Compared to estrogen receptor (ER)-positive breast cancers, ER-negative (ER-) breast cancers have worse prognoses and no effective prevention strategies. In this study, we will explore new strategies for immunoprevention of ER- breast cancer. Inducing potent anti-tumor immunity for prevention of poorly immunogenic breast cancers has been highly challenging. Engagement and expansion of activated dendritic cells (DCs) could facilitate broad and efficient anti-tumor immunities. However, certain existing DC stimulators (e.g., agonists of toll-like receptors and STING) also triggered adverse immune responses. For cancer prevention, it is imperative to develop safe and effective approaches to boost DC immunity. To this end, we screened for dietary supplements that increase DC activities and identified natural vitamin E (VitE) as a stimulator of DC functions. Excitingly, we found that breast cancer patients who took VitE during immunotherapies had a significantly better survival rate and improved therapeutic response than patients who didn’t take VitE, suggesting that VitE administration may potentiate anti-tumor immunity. Indeed, systemic (oral) administration and local (at injection site together with cancer vaccines) delivery of VitE significantly prolonged tumor-free survival in ER- mammary tumor mouse models that didn’t respond to cancer vaccines alone. These data led us to hypothesize that VitE administration, via reinforcing DC activation and antigen presentation, enhances immunoprevention of ER- breast cancer by cancer vaccines. We will test whether VitE could enhance cancer vaccine-induced immune surveillance and prevent/delay tumor initiation/progression in genetic engineered mouse models of (HER2+ and basal-like subtypes) ER- mammary tumors and the CD34+ humanized mouse models (for prevention of human ER- breast cancers) (Aim1). As a proof of concept, we will primarily use a triple- antigen (tumor associated antigens neu/IGFBP-2/IGF-IR) peptide vaccine (TAVac) for proposed studies since TAVac has shown partial efficacy in delaying tumor progression in ER- mammary tumor mouse models. Importantly, corresponding DNA vaccines against human HER2/IGFBP-2/IGF-IR are currently under phase I/II clinical studies for prevention of HER2+ and HER2- breast cancer recurrence. To gain mechanistic insights into how VitE potentiates anti-tumor immunity, we will investigate i) the global effect of VitE on the immune cell landscape by mass cytometry (CyTOF); ii) the impact of VitE on DC and T-cell subset compositions, functionality and signaling networks; iii) major immunophenotype changes critical for VitE-enhanced immunoprevention; iv) how VitE prompts antigen processing/presentation in DCs and whether VitE functions through SHP1, a critical DC checkpoint (Aim2). Finally, we will test novel strategies to further improve the immunoprevention efficacy against ER- mammary tumors (Aim3). If successful, our strategies could be readily tested in future clinic trials for immunoprevention of breast cancer, particularly, for women at high risk for ER- breast cancer.