Targeting mechanisms of immune evasion in chemotherapy-induced senescent cells

项目摘要/摘要 乳房肿瘤很少能通过化疗根除。残留病的存在有两个原因：肿瘤细胞1) 避免因细胞凋亡、有丝分裂灾难和营养缺乏而死亡；2)避免免疫清除。我们的 先前的研究已经证实，通过激活P53介导的停滞和衰老程序，肿瘤 细胞通过有丝分裂灾难、细胞凋亡和营养缺乏来避免死亡。我们显示化疗已经过了 携带p53野生型肿瘤的乳腺癌患者与携带突变型p53的患者相比，存活率很低。 肿瘤。衰老细胞通过产生细胞因子和趋化因子(称为 衰老相关分泌表型，或SASP)。 先前研究的弱点是未能确定经过治疗的衰老肿瘤细胞如何避免 免疫清除。在这项提案中，我们提出了令人信服的初步数据，以解决这一弱点，并 计划充分描述和研究以逃避细胞死亡为目标的潜在治疗途径， 从而促进免疫清除，提高存活率。在初步数据中，我们发现了一个值得注意的 PD-L1在持续性残留病中的上调可能是通过与基质细胞的相互作用介导的。 在复发中保持表达，表明有很强的选择性压力。 这个项目的目标是确定机制和制定策略，以特别针对免疫逃避。 在化疗后进入衰老状态的肿瘤细胞中。 假设：间质干扰素γ在化疗中诱导特定细胞亚群的PD-L1- 治疗过的衰老肿瘤。可以使用一种新的策略来靶向这些持续衰老的肿瘤细胞 结合抗衰老药物诱导免疫原性细胞死亡，然后是免疫检查点抑制剂。 在目标1中，我们将使用小鼠乳腺肿瘤模型来确定PD-L1表达的肿瘤细胞是否有更大的 比较同一治疗肿瘤中不表达PD-L1的细胞的复发潜力，以及每种细胞对 再治疗。我们将描述表达PD-L1的细胞与不表达PD-L1的细胞的基因表达差异。 在目标2中，我们将在体内确定PD-L1上调衰老肿瘤细胞所需的因素。 我们将把乳腺肿瘤移植到缺乏T细胞等特定免疫成分的同基因小鼠体内， 化疗，并确定PD-L1表达和免疫环境的变化。 在目标3中，初步数据显示只有三分之一的衰老小鼠乳腺肿瘤对抗PD-L1有反应 化疗后的治疗。我们将测试是否用BH3模拟药物WE诱导免疫原性细胞死亡 已被证明具有衰老活性，可以改善对免疫检查点抑制剂的反应。 在目标4中，我们将使用多重免疫组织化学方法对人乳腺癌标本进行前后染色。 化疗以确定PD-L1在衰老肿瘤中是否被诱导表达。

Project Summary/Abstract Breast tumors are rarely eradicated by chemotherapy. Residual disease exists for 2 reasons: the tumor cells 1) avoid death from apoptosis, mitotic catastrophe, and nutrient deprivation; 2) avoid immune clearance. Our previous research has established that by activating p53-mediated programs of arrest and senescence, tumor cells avoid death by mitotic catastrophe, apoptosis, and nutrient deprivation. We showed chemotherapy treated breast cancer patients with p53 wild type tumors have dismal survival compared to patients with p53 mutant tumors. Senescent cells promote relapse by their production of cytokines and chemokines (termed the senescence associated secretory phenotype, or SASP). The weakness of prior research has been a failure to identify how the treated, senescent tumor cells avoid immune clearance. In this proposal, we present compelling preliminary data addressing this weakness, and plans to fully characterize and investigate potential therapeutic avenues that target the evasion of cell death, thus facilitating immune clearance and improving survival. In preliminary data, we identify a remarkable upregulation of PD-L1 in the persisting residual disease likely mediated through interactions with stromal cells, and expression is maintained in the relapse, suggesting a strong selective pressure. The goal of this project is to identify mechanisms and develop strategies to target immune evasion specifically in tumor cells that have survived chemotherapy by entering senescence. Hypothesis: Stromal interferon gamma (IFNγ) induces PD-L1 in a specific subset of cells in a chemotherapy- treated, senescent tumor. These persisting, senescent tumor cells can be targeted using a novel strategy that combines senolytic drugs to induce immunogenic cell death followed by immune checkpoint inhibitors. In Aim 1 we will use mouse mammary tumor models to determine if PD-L1 expressing tumor cells have greater relapse potential than cells within the same treated tumor that do not express PD-L1, and how each responds to retreatment. We will characterize gene expression differences in cells that express PD-L1 vs. those that do not. In Aim 2 we will identify the factors in vivo that are required for PD-L1 upregulation on senescent tumor cells. We will transplant mammary tumors into syngeneic mice that lack specific immune components such as T cells, treat with chemotherapy, and determine changes in PD-L1 expression and immune contexture. In Aim 3, preliminary data show only one third of senescent mouse mammary tumors responded to anti-PD-L1 therapy following chemotherapy. We will test if inducing immunogenic cell death with BH3 mimetic drugs we have shown to have senolytic activity can improve the response to immune checkpoint inhibitors. In Aim 4, we will use multiplex immunohistochemistry staining of human breast cancer specimens pre and post chemotherapy to determine if PD-L1 expression is induced in senescent tumors.