Function and Mechanism of TET Regulation of Tumor Immunity

项目摘要 癌症基因组研究发现，新发现的癌症驱动基因中有近一半编码蛋白质。 参与组蛋白或DNA修饰，包括DNA双加氧酶Tet家族。功能丧失 Tet基因突变在人类血液系统恶性肿瘤中发生得较早和频繁。Tet基因的突变， 然而，这种情况在实体肿瘤中并不常见。相反，在不同类型的人类中，Tet的活性显著降低 肿瘤。我们不知道Tet活性降低在实体瘤中的意义。在这项研究中，我们假设 Tet在JAK-STAT和NF-κ通路中都具有以前未被认识到的关键功能。停用 TET会导致慢性促癌性炎症和逃避抗肿瘤免疫。因此，激动人心 Tet活性为增强抗肿瘤免疫和改进免疫治疗提供了一个可行的机会。我们 我将通过定义TET2活动的以下方面来检验这一假设：TET2的功能和机制 TET2在JAK-STAT通路和肿瘤免疫中的作用(AIM 1)；TET2与肿瘤的调节 可逆单糖基化免疫(目标2)；以及催化非依赖功能和 TET2抑制肿瘤的机制(目标3)。 在过去的资助期间，我们取得了以下发现，对TET产生了重大影响 形成本次调查的基础：(1)由以下因素产生或积累的多种共生代谢产物 不同代谢酶的突变作为α-酮戊二酸(αKG)的拮抗剂，抑制多个αKG- 依赖酶，包括Tet酶。(2)Tet的活性在体内是动态调节的。(3)发展 许多不同类型的实体肿瘤的发生与Tet活性的显著降低有关。(4)Tet is CRL4VprBP E3连接酶和UPS15脱泛素酶可逆单泛素化，增强和损害TET 活动分别为。这种调节被TET2中多次复发的肿瘤衍生突变所扰乱。(5)艾滋病毒 蛋白质VPR重新编程CRL4VprBP E3连接酶以催化Tet蛋白的多泛素化和降解 维持促炎细胞因子的表达，促进HIV的致病作用。(6)多序列- 特异性转录因子(TF)向其靶基因募集TET2，包括NF-κB和STAT成员 家人。(7)肿瘤中TET2功能的丧失会损害干扰素信号、趋化因子的产生和T细胞 对肿瘤免疫和免疫治疗具有抵抗力。 这次调查是建立在我们对当时新发现的TET的开创性和广泛研究的基础上的 酵素。它将研究细胞因子信号和肿瘤免疫调节的一个新方面-通过Tet- 介导的DNA去甲基化。它将使用新开发的技术和小鼠品系来确定Tet如何 蛋白质通过催化依赖和非催化的机制调节基因表达。它将探索一种 Tet可逆单糖基化的新调控及其治疗机会。这 本研究首次对Tet在肿瘤免疫中的作用和机制进行了探索。

Project Abstract Nearly half of newly discovered cancer driver genes discovered by the cancer genomic studies encode proteins involved in histone or DNA modification, including the TET family of DNA dioxygenases. Loss-of-function mutations in TET genes occur early and frequently in human hematopoietic malignancy. Mutations in TET genes, however, are uncommon in solid tumors. Instead, TET activity is significantly reduced in different types of human tumors. We do not know the significance of decreased TET activity in solid tumors. In this study, we hypothesize that TET has a previously unrecognized key function in both the JAK-STAT and NF-κ pathways. Inactivation of TET in results in chronic tumor-promoting inflammation and escape from anti-tumor immunity. Thus, stimulating TET activity represents a viable opportunity to enhance antitumor immunity and to improve immunotherapy. We will test this hypothesis by defining the following aspects of TET2 activity: The function and mechanism of TET2 in the JAK-STAT pathway and in tumor immunity (Aim 1); The regulation of TET2 and tumor immunity by reversible monoubiquitylation (Aim 2); and The catalytically independent function and mechanism of TET2 in tumor suppression (Aim 3). During the past funding period, we have made the following discoveries that significantly affect the TET field and that form the foundation for this investigation: (1) Multiple oncometabolites produced or accumulated by mutations in different metabolic enzymes act as antagonists α-ketoglutarate (αKG) and inhibit multiple αKG- dependent enzymes, including TET enzymes. (2) TET activity is dynamically regulated in vivo. (3) Development of solid tumors of many different types is associated with a substantial decrease in TET activity. (4) TET is reversibly monoubiquitylated by CRL4VprBP E3 ligase and UPS15 deubiquitylase, enhancing and impairing TET activity, respectively. This regulation is disrupted by multiple recurrent tumor-derived mutations in TET2. (5) HIV protein Vpr reprograms CRL4VprBP E3 ligase to catalyze polyubiquitylation and degradation of TET proteins to sustain the expression of pro-inflammatory cytokine and promote HIV pathogenesis. (6) Multiple sequence- specific transcription factors (TFs) recruit TET2 to their target genes, including members of NF-κB and STAT families. (7) Loss of TET2 function in tumors impairs interferon signaling, chemokine production, and T cell infiltration, and confers resistance to tumor immunity and immunotherapy. This investigation is built on our pioneering and extensive study of the then newly discovered TET enzymes. It will investigate a novel aspect of cytokine signaling and tumor immunity regulation—by TET- mediated DNA demethylation. It will use newly developed technology and mouse strains to determine how TET proteins regulate gene expression by catalytically-dependent and -independent mechanisms. It will explore a novel regulation of TET by reversible monoubiquitylation and the therapeutic opportunity of this regulation. This investigation represents the first exploration on the function and mechanism of TET in tumor immunity.