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: 10597540
• 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 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10597540
• 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; Environment; Epigenetic Process; Folic Acid; Folic Acid Deficiency; Frequencies; Genetic Polymorphism; Genetic Transcription; Genomics; Goals; Human; Immune; Immune checkpoint inhibitor; Infection; Infiltration; Inflammatory Response; Interferon Type I; Interferons; Investigational Drugs; Lesion; Lymphoma; Malignant Neoplasms; Mammalian Cell; Methotrexate; Molecular; Mus; Pathway interactions; Patients; Pemetrexed; Periodicity; Phase I Clinical Trials; Physiological; Positioning Attribute; Post-Transcriptional Regulation; 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; Tissues; Tumor Immunity; analog; cancer cell; cancer immunotherapy; checkpoint therapy; clinical efficacy; clinical translation; cytokine; ds-DNA; extracellular; folate-binding protein; human tissue; immunogenicity; improved; inhibitor therapy; innate immune sensing; insight; neoplastic cell; novel; overexpression; pharmacologic; pre-clinical; preclinical study; promoter; protein protein interaction; response; sensor; success; symporter; 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.

摘要 在哺乳动物细胞中，环二核苷酸(CDN)作为显著的危险信号，由先天感知 免疫传感器，干扰素基因刺激物(刺激物)。SING的激活引发了一个信号级联反应， 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-单磷酸腺苷(GMP-AMP)合成酶，由双链激活 DNA合成CDN，2‘，3’-cGAMP。除细胞内CDN外，刺激性CDN还可以 来源于细胞外来源，如治疗性CDN、肿瘤细胞产生的cGAMP和来自 胞外细菌。CGAS-STING通路在抗肿瘤免疫中的作用支持STING的使用 作为癌症治疗药物的激动剂。受2‘3’-cGAMP激活人体刺痛的发现启发 合成了强大的下游干扰素信号、刺激剂(主要是2‘，3’-cGAMP类似物)。 通过T细胞驱动的肿瘤，STIN的直接药理激活被证明限制了肿瘤的生长 消退机制，增强免疫原性。CGAMP在荷瘤小鼠体内的应用 增强了免疫检查点抑制剂和放射治疗的疗效。基于以下结果 CDN类似物在小鼠中，两个I期临床试验开始在肿瘤内递送STING激动剂 (ADU-S100和MK-1454)对实体瘤和淋巴瘤。尽管刺痛具有令人印象深刻的抗肿瘤活性 在小鼠身上，这种激动剂的临床试验的初步结果表明，这种激动剂对人类的疗效较低。 CDN的进出口和退化之间的监管相互作用仍然是一个重要和 未来研究的有趣领域。外源2‘3’-cGAMP和合成CDN，包括研究 新药(IND)2‘3’-CDAS用于癌症免疫治疗，穿越细胞膜还原 叶酸载体(RFC；SLC19A1)激活靶细胞中的STING，以及质子偶联叶酸转运体(PCFT； SLC46A1)增强了这种反应。RFC和PCFT是人体组织中叶酸的主要促进性转运体 还有肿瘤。PCFT与RFC的独特之处在于它具有酸性而不是中性的最佳pH。RFC和PCFT 临床使用的甲氨蝶呤和培美曲塞等共享底物，也显示出各自独特的底物 具体细节。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。在本R03中 应用，我们探索RFC的独特生物学，以及PCFT，以及癌症中的刺激剂，目的是 进一步了解这些促进性转运蛋白对CDN的摄取，进而改善 治疗应用。在目标1中，我们建议研究RFC和PCFT在以下条件下摄取CDN的机制 生理条件。在目标2中，我们将研究RFC对CDN摄取的分子调控， 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翻译的潜力而独树一帜。