Targeting of tumor cell DHHC3 to enhance anti-cancer immunity

项目摘要 动员适应性和先天性免疫细胞在乳腺癌的治疗中具有相当大的效用 和其他癌症。在这里，我们提供了一种新的方法。我们的中心目标是证明消融术如何 蛋白质酰基转移酶DHHC 3可以增强适应性和先天性抗癌免疫。 为了实现这一目标，我们已经表明，ZDHHC 3消融i）显著降低了 肿瘤细胞上的检查点阻断分子PD-L1，和ii）破坏CMTM 6，CMTM 6是维持肿瘤细胞增殖所需的分子， PD-L1表达，从而CMTM 6棕榈酰化被消除，亚细胞定位显著改变。 此外，iii）用野生型DHHC 3而不是酶失活的DHHC 3恢复，恢复PD-L1 程度.此外，iv）ZDHHC 3消融显著降低裸鼠中的肿瘤异种移植物生长（但在裸鼠中不显著）。 体外）通过涉及升高的氧化应激、衰老和先天免疫清除肿瘤的机制 细胞因为DHHC 3酶可以调节适应性和先天性抗癌免疫，但不是 正常小鼠生理所需，它可能是一个有用的治疗靶点。我们的核心指导假设 i）DHHC 3消融阻止CMTM 6棕榈酰化，导致未保护的PD-6降解， L1对肿瘤细胞的作用，这增强了适应性免疫，以及ii）DHHC 3消融也增强了 先天免疫，具有氧化应激的关键调节因子（例如ERGIC 3、TXNIP）和先天免疫细胞 (e.g. NK细胞）发挥重要作用。这些假设将被测试如下：目的1，我们将使用各种 体外和体内实验，以确定DHHC 3消融增强适应性的程度 通过涉及CMTM 6棕榈酰化损失的机制导致PD-L1表达减少，从而导致免疫力下降。 目的2，我们将评估乳腺肿瘤细胞DHHC 3消融对先天性和适应性的相对体内影响。 抗乳腺癌免疫，我们将评估氧化应激，衰老和NK细胞的关键贡献 细胞与先天免疫预期影响：结果应支持DHHC 3作为新型肿瘤的效用 靶向乳腺癌和其他癌症，因为从肿瘤细胞中切除DHHC 3同时增强了 适应性和先天性免疫，CMTM 6，PD-L1，氧化应激和NK细胞发挥关键作用。

Project Summary Mobilization of both adaptive and innate immune cells has considerable utility in the treatment of breast cancer and other cancers. Here we provide a novel approach. Our central goal is to demonstrate how ablation of the protein acyl transferase, DHHC3, can enhance both adaptive and innate anti-cancer immunity. Towards achieving this goal, we have already shown that ZDHHC3 ablation i) markedly diminishes levels of checkpoint blockade molecule PD-L1 on tumor cells, and ii) disrupts CMTM6, a molecule needed to maintain PD-L1 expression, such that CMTM6 palmitoylation is abolished and subcellular localization markedly altered. Furthermore, iii) restoration with wild type DHHC3, but not enzymatically inactive DHHC3, restores PD-L1 levels. In addition, iv) ZDHHC3 ablation markedly reduces tumor xenograft growth in nude mice (but not in vitro) by a mechanism involving elevated oxidative stress, senescence, and tumor clearance by innate immune cells. Because the DHHC3 enzyme may regulate both adaptive and innate anti-cancer immunity, but is not needed for normal mouse physiology, it may be a useful therapeutic target. Our central guiding hypotheses are i) that DHHC3 ablation prevents CMTM6 palmitoylation, leading to degradation of unprotected PD- L1 on tumor cells, which enhances adaptive immunity and ii) that DHHC3 ablation also enhances innate immunity, with key regulators of oxidative stress (e.g. ERGIC3, TXNIP) and innate immune cells (e.g. NK cells) playing major roles. These hypotheses will be tested as follows: Aim 1, We will use a variety of in vitro and in vivo experiments to establish the extent to which DHHC3 ablation enhances adaptive immunity by a mechanism involving loss of CMTM6 palmitoylation leading to diminished PD-L1 expression. Aim 2, We will assess relative in vivo effects of mammary tumor cell DHHC3 ablation on innate and adaptive anti-breast cancer immunity, and we will evaluate key contributions of oxidative stress, senescence, and NK cells to innate immunity. Expected Impact: Results should support the utility of DHHC3 as a novel tumor target in breast cancer and other cancers, as DHHC3 ablation from tumor cells simultaneously enhances both adaptive and innate immunity, with CMTM6, PD-L1, oxidative stress, and NK cells playing key roles.