Biology of major folate transporters and STING signaling in cancer

主要叶酸转运蛋白的生物学和癌症中的 STING 信号传导

• 批准号: 10435010
• 负责人: Zhanjun Hou
• 金额: $ 7.7万
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-05 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10435010
• 关键词: Adenosine Monophosphate; Agonist; Anions; Area; Bacteria; Biology; CD8B1 gene; Cell membrane; Cell model; Cells; Clinical; Clinical Data; Clinical Trials; Code; Complex; Coupled; Cyclic GMP; Cytosol; DNA; Dinucleoside Phosphates; Dose; Endoplasmic Reticulum; Ensure; Epigenetic Process; Folic Acid; Frequencies; Genetic Polymorphism; Genetic Transcription; Goals; Guanosine Monophosphate; Human; Immune; Immune checkpoint inhibitor; Infection; Infiltration; Inflammatory; Inflammatory Response; Interferon Type I; Interferons; Investigational Drugs; Lesion; Light; Lymphoma; Malignant - descriptor; Malignant Neoplasms; Mammalian Cell; Methotrexate; Molecular; Mus; Pathway interactions; Patients; Pemetrexed; Periodicity; Pharmacology; Phase I Clinical Trials; Physiological; Positioning Attribute; Protons; Publishing; Radiation therapy; Regulation; Reporting; Research; Role; SLC19A1 gene; Signal Transduction; Solid Neoplasm; Source; Specificity; Stimulator of Interferon Genes; Structure; Substrate Specificity; System; T-Lymphocyte; Tetrahydrofolates; Therapeutic; Therapeutic Effect; Time; Tissues; Tumor Immunity; analog; base; cancer genomics; cancer immunotherapy; clinical efficacy; clinical translation; cytokine; ds-DNA; extracellular; folate-binding protein; human tissue; immunogenicity; improved; innate immune sensing; insight; neoplastic cell; novel; overexpression; pre-clinical; preclinical study; promoter; protein protein interaction; response; sensor; success; tool; tumor; tumor growth; uptake

ABSTRACT In mammalian cells, cyclic dinucleotides (CDNs) act as prominent danger signals that are sensed by the innate immune sensor, stimulator of interferon genes (STING). Activation of STING elicits a signaling cascade that culminates in the induction of type I interferons (IFNs) and various cytokines, thereby promoting a powerful inflammatory response. Mammalian cells are able to produce their own CDNs, catalyzed by the cyclic guanosine monophosphate–adenosine monophosphate (GMP-AMP) synthase (cGAS), which is activated by double-strand DNAs to synthesize the eukaryotic CDN, 2′3′-cGAMP. Beyond intracellular CDNs, STING-activating CDNs can originate from extracellular sources, such as therapeutic CDNs, cGAMP produced by tumor cells, and CDNs from extracellular bacteria. The role of the cGAS-STING pathway in anti-tumor immunity supports the use of STING agonists as cancer therapeutics. Inspired by the discovery that 2′3′-cGAMP activates human STING to initiate robust downstream IFN signaling, STING-activating agents (mostly 2′3′-cGAMP analogues) were synthesized. Direct pharmacologic activation of STING was shown to restrict tumor growth by a T cell-driven tumor regression mechanism and to enhance immunogenicity. Administration of cGAMP in tumor-bearing mice also potentiated the therapeutic effects of immune-checkpoint inhibitors and radiotherapy. Based on results with CDN analogs in mice, two phase I clinical trials were initiated for the intra-tumoral delivery of STING agonists (ADU-S100 and MK-1454) to solid tumors and lymphomas. Despite the impressive anti-tumor activity of STING agonists in mice, initial results from clinical trials of such agonists have indicated a lower efficacy in humans. The regulatory interplay among the import, export and degradation of CDNs remains an important and interesting area for future research. Exogenous 2′3′-cGAMP and synthetic CDNs, including the investigational new drug (IND) 2′3′-CDAS used in cancer immunotherapy, traverse the cell membrane through the reduced folate carrier (RFC; SLC19A1) to activate STING in target cells, and the proton-coupled folate transporter (PCFT; SLC46A1) enhances such response. RFC and PCFT are major facilitative transporters of folate in human tissues and tumors. PCFT is unique from RFC in that it has an acidic rather than neutral pH optimum. RFC and PCFT share substrates such as clinically used methotrexate and pemetrexed but also show their own unique substrate specificities. Our group has studied RFC and PCFT structure, function and regulation extensively. In this R03 application, we explore the unique biology of RFC, as well as PCFT, and STING agonists in cancer, with a goal of further understanding CDN uptake by these facilitative transporters and, by extension, improving therapeutic applications. We propose in Aim 1 to study mechanisms of CDN uptake by RFC and PCFT under physiological conditions. In Aim 2, we will study the molecular regulation of RFC in relation to CDN uptake, including transcriptional epigenetics, and the potential role of protein-protein interactions in regulating RFC. Our proposed studies are distinctive for their novelty and potential for clinical translation.

抽象的 在哺乳动物细胞中，环状二核苷酸 (CDN) 充当着重要的危险信号，被先天细胞感知到。 免疫传感器，干扰素基因刺激器（STING）。 STING 的激活会引发信号级联反应 最终诱导 I 型干扰素 (IFN) 和各种细胞因子，从而促进强大的 炎症反应。哺乳动物细胞能够在环鸟苷的催化下产生自己的 CDN 单磷酸腺苷 (GMP-AMP) 合酶 (cGAS)，由双链激活 用于合成真核 CDN、2'3'-cGAMP 的 DNA。除了细胞内 CDN 之外，STING 激活 CDN 还可以 源自细胞外来源，例如治疗性 CDN、肿瘤细胞产生的 cGAMP 以及来自 胞外细菌。 cGAS-STING 通路在抗肿瘤免疫中的作用支持 STING 的使用 激动剂作为癌症治疗剂。受到 2′3′-cGAMP 激活人类 STING 启动这一发现的启发 合成了强大的下游 IFN 信号传导、STING 激活剂（主要是 2'3'-cGAMP 类似物）。 STING 的直接药理学激活被证明可以通过 T 细胞驱动的肿瘤限制肿瘤生长 回归机制并增强免疫原性。在荷瘤小鼠中也给予 cGAMP 增强了免疫检查点抑制剂和放射疗法的治疗效果。基于结果 CDN类似物在小鼠体内启动了两项I期临床试验，用于肿瘤内递送STING激动剂 （ADU-S100 和 MK-1454）实体瘤和淋巴瘤。尽管 STING 具有令人印象深刻的抗肿瘤活性 尽管在小鼠中使用激动剂，但此类激动剂临床试验的初步结果表明，在人类中的疗效较低。 CDN 的导入、导出和降级之间的监管相互作用仍然是一个重要且重要的问题。 未来研究的有趣领域。外源 2′3′-cGAMP 和合成 CDN，包括研究中的 新药（IND）2′3′-CDAS用于癌症免疫治疗，通过还原酶穿过细胞膜 叶酸载体（RFC；SLC19A1）激活靶细胞中的 STING，以及质子耦合叶酸转运蛋白（PCFT；SLC19A1） SLC46A1) 增强了这种响应。 RFC 和 PCFT 是人体组织中叶酸的主要促进转运蛋白 和肿瘤。 PCFT 与 RFC 的独特之处在于它具有酸性而不是中性 pH 最佳值。 RFC 和 PCFT 共享底物，例如临床使用的甲氨蝶呤和培美曲塞，但也展示了自己独特的底物 特殊性。我们课题组对RFC和PCFT的结构、功能和调控进行了广泛的研究。在这个R03 应用中，我们探索 RFC 以及 PCFT 和 STING 激动剂在癌症中的独特生物学，目标 进一步了解这些辅助转运蛋白对 CDN 的吸收，进而提高 治疗应用。我们在目标 1 中建议研究 RFC 和 PCFT 下的 CDN 吸收机制 生理条件。在目标 2 中，我们将研究 RFC 与 CDN 摄取相关的分子调控， 包括转录表观遗传学，以及蛋白质-蛋白质相互作用在调节 RFC 中的潜在作用。 我们提出的研究因其新颖性和临床转化潜力而与众不同。