ATR: targeting mechanical stress induced EMT and immune suppression in triple negative breast cancer

项目描述/摘要 治疗抗性三阴性乳腺癌（TNBC）的特征在于间充质特征， 促进免疫逃避和疾病进展，导致高死亡率的疾病。新 需要靶向间充质表型以克服治疗抗性的策略。相互作用 癌细胞的细胞骨架和周围的细胞外基质之间的相互作用在启动 局部浸润和转移。由此产生的机械刺激激活信号传导通路， 非运动性极化上皮细胞向具有间充质性质的细胞的转变， 并逃避免疫监视，这一过程被称为上皮细胞向间质细胞转化， （EMT）。由细胞外基质沉积引起的非细胞间质的纤维化硬化是一种常见的 这是TNBC和其他恶性肿瘤的特征，与治疗抗性和不良预后相关。如何 机械应力促进EMT和癌症进展尚未阐明。 共济失调毛细血管扩张症突变和Rad-3相关（ATR）是最有名的DNA损伤的调节剂 复制细胞的反应。在我们的初步数据中，我们发现ATR蛋白的高表达是 与TNBC无进展生存期降低相关。我们发现ATR是一种事后的 由去泛素化酶USP 21上调，以响应机械应力，ATR调节 核骨架和细胞骨架复合物的连接体（LINC）促进β-catenin核转位， 机械应力诱发EMT ATR在机械应力和EMT中的这种新作用独立于ATR的 在调节DNA损伤反应中建立功能。在一项抗PD-1免疫疗法用于 在晚期TNBC中，活检标本中的高ATR水平与EMT和反应性降低相关。 ATR抑制可促进体内间质上皮转化和抗肿瘤免疫。我们 假设ATR调节机械应力后的LINC复合物，以促进β-连环蛋白介导的 EMT、免疫逃避和TNBC进展。我们将通过三个具体目标来检验这一假设。要求1 将研究机械应力对ATR去泛素化和LINC复合物的影响;目标2将评估 ATR如何影响β-catenin通路激活和EMT;目标3将研究ATR-SUN 2在 僵硬和EMT相关的免疫逃避。

PROJECT DESCRIPTION/ABSTRACT Therapeutically resistant triple negative breast cancer (TNBC) is characterized by mesenchymal features that facilitate immune evasion and disease progression, resulting in high rates of death from the disease. New strategies targeting the mesenchymal phenotype to overcome therapeutic resistance are needed. Interactions between the cytoskeleton of cancer cells and the surrounding extracellular matrix play important roles in initiating local invasion and metastasis. The resulting mechanical stimuli activate signaling pathways which promote the transition of non-motile polarized epithelial cells to cells with mesenchymal properties that are able to invade surrounding tissues and evade immune surveillance, a process termed epithelial to mesenchymal transition (EMT). Fibrotic stiffening of the non-cellular stroma resulting from extracellular matrix deposition is a common feature of TNBC and other malignancies that is associated with therapeutic resistance and poor prognosis. How mechanical stress promotes EMT and cancer progression has not been elucidated. Ataxia Telangiectasia Mutated and Rad-3 Related (ATR) is best known as a regulator of the DNA damage response in replicating cells. In our preliminary data, we have found that high ATR protein expression is associated with reduced progression-free survival in TNBC. We discovered that ATR is post-translationally upregulated by a deubiquitinating enzyme, USP21, in response to mechanical stress, and that ATR regulates the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex to promote β-catenin nuclear translocation and mechanical stress-induced EMT. This new role for ATR in mechanical stress and EMT is independent of ATR’s established function in regulating the DNA damage response. In a clinical trial of anti-PD-1 immunotherapy for advanced TNBC, high ATR levels in biopsy specimens was correlated with EMT and reduced responsiveness. ATR inhibition could promote mesenchymal to epithelial transition and anti-tumor immunity in vivo. We hypothesize that ATR regulates the LINC complex following mechanical stress to promote β-catenin mediated EMT, immune evasion, and TNBC progression. We will test this hypothesis through three specific aims. Aim 1 will examine the impact of mechanical stress on ATR deubiquitination and the LINC complex; Aim 2 will evaluate how ATR influences β-catenin pathway activation and EMT; Aim 3 will investigate the role of ATR-SUN2 in stiffness and EMT associated immune evasion.