ST8Sia6 expression on tumors inhibits the immune response

肿瘤上 ST8Sia6 的表达抑制免疫反应

• 批准号: 10529298
• 负责人: Virginia Smith Shapiro
• 金额: $ 39.14万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-12-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10529298
• 关键词: Acceleration; Amaze; Bone Marrow; CTLA4 gene; Cell surface; Cells; Coculture Techniques; Colon Carcinoma; Databases; Development; Down-Regulation; Doxycycline; Engineering; Family; Frequencies; Glycolipids; Growth; HuR protein; Human; Immune; Immune checkpoint inhibitor; Immune response; Immune system; Immunotherapy; Impairment; Innate Immune System; Knockout Mice; Ligands; MC38; Macrophage; Maintenance; Malignant Neoplasms; Mediating; Membrane Glycoproteins; Microsatellite Instability; Modeling; Modification; Mus; PD-1/PD-L1; Patients; Phenotype; Play; Pre-Clinical Model; Predisposition; RNA-Binding Proteins; Regulation; Role; Sialic Acids; Signal Pathway; T cell response; T-Cell Activation; T-Lymphocyte; Testing; Tetanus Helper Peptide; Therapeutic Intervention; Transferase; Transgenes; Transplantation; Tumor Cell Line; Tumor Promotion; Tumor-associated macrophages; anti-PD-L1 therapy; cancer immunotherapy; cancer type; cell growth; conditional knockout; glycosylation; immune activation; immune checkpoint blockade; immunoregulation; in vivo; in vivo Model; lymph nodes; mRNA Stability; mouse model; neoplastic cell; novel; overexpression; programmed cell death ligand 1; programmed cell death protein 1; receptor; recruit; response; sialic acid binding Ig-like lectin; sialylation; success; synergism; targeted treatment; tumor; tumor growth; tumorigenic

Checkpoint blockade, which targets inhibitory receptors that suppress successful T cell responses to tumors, demonstrates the critical role that the immune response plays against cancer. However, not all cancers respond to immunotherapy or checkpoint blockade targeting PD-1 or CTLA-4 on T cells. For example, the majority of patients with colon cancer do not respond to checkpoint inhibitor monotherapy, which is effective in only 4% of patients with microsatellite instability. Thus, many tumors may target other inhibitory receptors or different components of the immune system to block it from mounting an effective response. One family of inhibitory receptors on immune cells is the Siglec family, which recognize ligands with sialic acid modifications on cell surface glycoproteins or glycolipids. There are twenty eukaryotic sialic acid transferases, each of which differ in their preferred linkage, targets and number of sialic acids added. It has been long recognized that tumors alter the type and frequency of glycosylation and sialic acid on the cell surface. In particular, increased incorporation of sialic acid is frequently observed in cancer, although the function of hyper-sialylation in promoting and sustaining tumor growth is not well understood. Interestingly, using the COSMIC database, we found that while 389 human tumors over-expressed the sialic acid transferase ST8Sia6, none under-expressed ST8Sia6; this indicates a strong selective advantage for tumors with high ST8Sia6, although the function of ST8Sia6 in cancer is not known. We demonstrated that ST8Sia6 overexpression in either MC38 or B16-F10 tumor cell lines accelerated tumor growth in mice. Tumor associated macrophages (TAMs) in ST8Sia6- expressing tumors possessed an M2-like phenotype, as compared to a M1-like phenotype in tumors formed from the parental MC38 or B16-F10 tumor cell lines that lack ST8Sia6 expression. We demonstrated that ST8Sia6 generates ligands for the inhibitory Siglec, Siglec-E, whose expression is restricted to innate immune cells. The growth advantage of ST8Sia6-expressing tumor cells was lost when injected into Siglec-E knockout mice, demonstrating that the primary effect of ST8Sia6 overexpression is on inhibition of the immune response of the host rather than an intrinsic effect on cell growth. We have developed a novel cre-dependent, dox- regulatable ST8Sia6 transgene to study the effect of ST8Sia6 in spontaneous tumor models. Overexpression of ST8Sia6 in a spontaneous model of colon cancer dramatically decreased survival to 2-3 months instead of 6 months, demonstrating the strong effect ST8Sia6 overexpression has on tumor cell growth in vivo. This proposal will examine the function of ST8Sia6 in modulating the immune response to tumors.

检查点封锁，针对抑制性受体，抑制 T 细胞对肿瘤的成功反应， 证明了免疫反应对癌症的关键作用。然而，并非所有癌症 对 T 细胞上针对 PD-1 或​​ CTLA-4 的免疫疗法或检查点封锁有反应。例如， 大多数结肠癌患者对检查点抑制剂单一疗法没有反应，而检查点抑制剂单一疗法在 只有4%的患者存在微卫星不稳定。因此，许多肿瘤可能靶向其他抑制性受体或 免疫系统的不同组成部分，以阻止其产生有效的反应。一个家庭 免疫细胞上的抑制性受体是 Siglec 家族，它识别具有唾液酸修饰的配体 作用于细胞表面的糖蛋白或糖脂。真核生物唾液酸转移酶有二十种，每一种 不同之处在于它们的首选连接、目标和添加的唾液酸数量。人们很早就认识到 肿瘤改变细胞表面糖基化和唾液酸的类型和频率。特别是增加了 在癌症中经常观察到唾液酸的掺入，尽管过度唾液酸化的功能 促进和维持肿瘤生长尚不清楚。有趣的是，使用 COSMIC 数据库，我们 发现虽然 389 个人类肿瘤过度表达唾液酸转移酶 ST8Sia6，但没有一个肿瘤表达不足 ST8Sia6；这表明对于具有高 ST8Sia6 的肿瘤具有很强的选择优势，尽管 ST8Sia6 在癌症中的作用尚不清楚。我们证明 ST8Sia6 在 MC38 或 B16-F10 中过度表达 肿瘤细胞系加速了小鼠肿瘤的生长。 ST8Sia6 中的肿瘤相关巨噬细胞 (TAM) 与形成的肿瘤中的 M1 样表型相比，表达肿瘤具有 M2 样表型 来自缺乏 ST8Sia6 表达的亲本 MC38 或 B16-F10 肿瘤细胞系。我们证明了 ST8Sia6 生成抑制性 Siglec、Siglec-E 的配体，其表达仅限于先天免疫 细胞。当注射到 Siglec-E 敲除中时，表达 ST8Sia6 的肿瘤细胞的生长优势消失了 小鼠，证明 ST8Sia6 过度表达的主要作用是抑制免疫反应 宿主的影响而不是对细胞生长的内在影响。我们开发了一种新型的依赖于 cre 的 dox- 可调节的 ST8Sia6 转基因来研究 ST8Sia6 在自发性肿瘤模型中的作用。过度表达 ST8Sia6 在自发性结肠癌模型中的表达显着将生存期从 6 个月缩短至 2-3 个月 几个月，证明 ST8Sia6 过表达对体内肿瘤细胞生长有强烈影响。这 该提案将检查 ST8Sia6 在调节肿瘤免疫反应中的功能。