Microbial Metabolite Mimics, PXR and Colitis-Induced Colorectal Cancer

微生物代谢物模拟物、PXR 和结肠炎诱发的结直肠癌

• 批准号: 9763500
• 负责人: Sridhar Mani
• 金额: $ 49.58万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-14 至 2023-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9763500
• 关键词: Acids; Acute; Adenocarcinoma; Adopted; Affinity; Agonist; Animal Model; Azoxymethane; Bile Acids; Binding; Biochemical; Biological; Biological Assay; Calorimetry; Cell Line; Cells; Chemicals; Colitis; Colitis associated colorectal cancer; Colon Carcinoma; Computer Simulation; Crystallization; Data; Development; Disease; Dysplasia; Fatty Liver; Functional disorder; Generations; Goals; Histology; Human; Hybrids; Immunity; In Vitro; Inbred BALB C Mice; Indoles; Indomethacin; Inflammation; Inflammatory disease of the intestine; Injury; Intestines; Laboratories; Lead; Libraries; Ligand Binding; Ligands; Liver diseases; Modeling; Molecular; Mucous Membrane; Mus; Nuclear Orphan Receptor; Nuclear Receptors; Periodicity; Pharmaceutical Preparations; Physiological; Principal Investigator; Property; Reproducibility; Rifampin; Sampling; Series; Signal Pathway; Signal Transduction; Sodium Dextran Sulfate; Source; Specificity; Structure; TLR4 gene; Testing; Time; Tissues; Transactivation; Tryptophan; United States Food and Drug Administration; Validation; adenoma; analog; base; carcinogenicity; clinical development; clinical translation; colon cancer prevention; cytotoxicity; design; drug discovery; drug structure; efficacy evaluation; enthalpy; experimental study; gut microbiome; human disease; improved; in vitro testing; in vivo; inflammatory marker; insight; intestinal homeostasis; lead optimization; microbial; mimicry; molecular modeling; mouse model; mutant; non-alcoholic fatty liver disease; novel; novel strategies; novel therapeutics; pharmacophore; potency testing; pregnane X receptor; programs; receptor; receptor binding; scaffold; screening; side effect; small molecule; small molecule therapeutics; symbiont; therapeutic target; translational medicine; treatment group; tumorigenesis

The project proposed directly targets the vexing problem of controlling aberrant inflammation-induced carcinogenic signals (e.g., TLR4) in the intestine by understanding the biological properties of adopted orphan nuclear receptors (ONRs). One of these receptors, Pregnane X Receptor (PXR), is abundantly expressed in the intestines and is a potential therapeutic target for colitis –associated colon cancer (CRC). Since existing treatments for colitis-associated CRC are limited and have significant side effects, non-toxic targeting of validated biological targets to prevent colon cancer is warranted. Based on our novel observations that IPA abrogates murine intestinal inflammation (IBD) directly through the non-hematopoietic Pregnane X Receptor (PXR)/Toll-like Receptor 4 (TLR4) signaling pathway, the goal of this project is to test the hypothesis that intestinal PXR can be uniquely modulated by small molecules designed to mimic the gut indole metabolites as a novel approach to treat IBD. Based on the indole/IPA chemical scaffold mimicry, this project will generate novel PXR ligands that can therapeutically target intestinal inflammation and colon cancer in humans, and will provide mechanistic insights into how these molecules binds to PXR. Our preliminary studies have shown that IPA derived from symbionts significantly reduces indomethacin-induced intestinal injury in mice in a PXR and TLR4 dependent manner. IPA regulates intestinal barrier function through PXR. An inverse relationship between PXR and TLR4 as well as IPA and inflammation in human intestinal samples and cell lines, supports our findings in mice. In mice, IPA is a potent activator of PXR, while the human receptor is effectively activated when combined with base indole at a physiologically relevant level. Human PXR LBD mutants were insensitive to activation by indole and IPA. Both Indole and IPA bind to PXR protein in solution. IPA protects against colitis-induced CRC in mice. Small molecule mimics (FKK) of indole/IPA chemical scaffold potently activate PXR and are non-toxic to cells and tissues. Thus, as PXR is a relevant target for intestinal inflammation, we hypothesize that microbial metabolite mimicry will allow for the design of novel, potent and most of all safe compounds that activate PXR and abrogate colitis-associated CRC. To achieve our goals we will (1) synthesize and validate in vitro FKK drug-like lead compounds targeting PXR using rational structure based design; (2) optimize lead FKK candidates based on binding affinity and specificity; (3) evaluate the in vivo efficacy of the lead FKK compounds in abrogating CRC using chemical hPXR mouse models of intestinal inflammation/CRC. In the short-term, we hope to have validated a single novel therapeutic lead based on their likelihood to safely abrogate CRC in mice. These studies can serve as the basis for further validation in human disease-specific animal models in the laboratory prior to embarking on clinical translation. Since PXR has been shown to significantly modulate barrier function in mice, our IPA-like leads could potentially have broader impact on other diseases propelled by a dysfunctional intestinal barrier.

提出的项目直接针对控制异常炎症引起的令人烦恼的问题， 致癌信号（例如，TLR 4）在肠道中的生物学特性 核受体（ONRs）。孕烷X受体（PXR）是这些受体中的一种，在哺乳动物中大量表达。 是结肠炎相关结肠癌（CRC）的潜在治疗靶点。因为现有 结肠炎相关CRC的治疗是有限的，并有显着的副作用，无毒的靶向治疗， 有效的生物靶点来预防结肠癌是必要的。根据我们的新观察， 直接通过非造血孕烷X受体消除小鼠肠道炎症（IBD） (PXR)/Toll样受体4（TLR 4）信号通路，该项目的目标是测试假设， 肠道PXR可以被设计为模拟肠道吲哚代谢物的小分子独特地调节， 治疗IBD的新方法。基于吲哚/IPA化学支架模拟，该项目将产生 新的PXR配体，可以治疗靶向人类肠道炎症和结肠癌， 提供了这些分子如何与PXR结合的机制见解。我们的初步研究表明， 来自共生体的IPA显著降低PXR小鼠中吲哚美辛诱导的肠损伤， TLR 4依赖性。IPA通过PXR调节肠道屏障功能。的反比关系 PXR和TLR 4以及IPA和人类肠道样品和细胞系中的炎症之间的关系， 我们在老鼠身上的发现。在小鼠中，IPA是PXR的有效激活剂，而人类受体被有效激活 当与生理相关水平的基础吲哚组合时。人PXR LBD突变体不敏感 吲哚和IPA活化。吲哚和IPA在溶液中均与PXR蛋白结合。IPA可防止 结肠炎诱导的小鼠CRC。吲哚/IPA化学支架的小分子模拟物（FKK）有效激活 PXR和对细胞和组织无毒。因此，由于PXR是肠道炎症的相关靶点，我们 假设微生物代谢物模拟将允许设计新颖、有效且最重要的是安全的 激活PXR并消除结肠炎相关CRC的化合物。为了实现我们的目标，我们将（1） 基于合理结构合成和体外验证靶向PXR的FKK类药物先导化合物 设计;（2）基于结合亲和力和特异性优化先导FKK候选物;（3）评估靶向FKK候选物。 使用化学hPXR小鼠肠转移模型，先导FKK化合物在消除CRC中的体内功效 炎症/CRC。在短期内，我们希望已经验证了一个单一的新型治疗铅的基础上， 安全消除小鼠CRC的可能性。这些研究可以作为进一步验证的基础 在进行临床转化之前，在实验室中对人类疾病特异性动物模型进行研究。以来 PXR已被证明可以显著调节小鼠的屏障功能，我们的IPA样先导物可以 潜在地对由功能失调的肠屏障推动的其他疾病具有更广泛的影响。