Small Molecule Induction of 15-PGDH: A Target in Colon Cancer Chemoprevention

15-PGDH 的小分子诱导：结肠癌化学预防的靶点

• 批准号: 8828504
• 负责人: John James Letterio
• 金额: $ 32.89万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8828504
• 关键词: Accounting; Address; Adenomatous Polyposis Coli; Alleles; Anabolism; Azoxymethane; Cancer Etiology; Carcinogen exposure; Cells; Cessation of life; Chemoprevention; Chemopreventive Agent; Clinical; Colitis; Colon; Colon Carcinoma; Colonic Neoplasms; Colonic Polyps; Coupling; Data; Dose; Enzyme Induction; Enzymes; Epidermal Growth Factor; Epithelial; FVB/N Mouse; Genes; Histone Deacetylase; Homeostasis; Human; Inflammation; Inflammation Mediators; Inflammatory; Intestinal Neoplasms; Laboratories; Lead; Lesion; Malignant Neoplasms; Metabolism; Modeling; Mucous Membrane; Mus; Oxidoreductase; PTGS2 gene; Pathway interactions; Patients; Play; Polyps; Pre-Clinical Model; Predisposition; Property; Prostaglandin-Endoperoxide Synthase; Prostaglandins; Recording of previous events; Relative (related person); Repression; Resistance; Role; Signal Pathway; Signal Transduction; Sodium Dextran Sulfate; Symptoms; TNF gene; Testing; Transcription Repressor/Corepressor; Tumor Suppressor Genes; Tumor Suppressor Proteins; United States; Work; adenoma; base; cancer chemoprevention; cancer therapy; carcinogenesis; celecoxib; colon carcinogenesis; cytokine; dietary supplements; efficacy testing; enzyme activity; high risk; inhibitor/antagonist; mouse model; novel; prevent; public health relevance; receptor; response; small molecule; tumor; tumorigenesis

DESCRIPTION (provided by applicant): The cyclooxygenase pathway is considered an important target in the chemoprevention and therapy of cancer. The prostaglandin (PG) degrading enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH), functions as an endogenous inhibitor of the colonic COX-2 pathway and as a colon tumor suppressor gene. There is now accumulating evidence that support the hypothesis that expression of 15-PGDH plays an important role in mucosal epithelial homeostasis, and that repression of 15-PDGH expression by inflammatory mediators may be an important step in colitis associated colon carcinogenesis. In particular, recent data indicate that the loss of 15-PGDH expression is an important determinant of the response to inhibitors of COX-2 in the context of cancer chemoprevention. Therefore, agents with a capacity to induce the expression of 15-PGDH may serve as an effective form of cancer chemoprevention, and may either enhance the response to or overcome the resistance to COX-2 inhibitors (such as celecoxib or Celebrex(R)). 15-PGDH is highly expressed in normal colon mucosa, but the expression of this enzyme is invariably lost in human colon cancers. In mice, a disruption of the gene encoding 15-PGDH leads to an increase in susceptibility to colon cancer, enhancing the susceptibility of the normally resistant C57BL/6J strain to colon tumor induction with azoxymethane (AOM) and leading to an increase in colon tumors arising in the APC+/Min (multiple intestinal neoplasia) mouse model.3 Mechanisms leading to this loss of 15-PGDH expression are not entirely clear, but a role for increased expression of histone deacetylase (HDAC) in human colon cancers in the repression of 15-PDGH expression has been demonstrated through a mechanism that involves the transcriptional repressor, Snail.5 In addition, repression of 15-PGDH by epidermal growth factor signaling and by inflammatory cytokines (TNF-a) has also been demonstrated. These data support the hypothesis that inflammation may promote tumorigenesis, in part, through coordinated effects on activities of enzymes of both prostaglandin biosynthesis and metabolism. To address this question, our laboratory now explores the ability of triterpenoids (natural and synthetic) to induce the expression of 15-PGDH, and whether an induction of this enzyme is associated with effective chemoprevention of colon cancer. The triterpenoids are a class of multifunctional small molecules that regulate multiple signaling pathways and have demonstrated chemopreventive activity in specific preclinical models of cancer. Our preliminary data demonstrate the ability of triterpenoids to: a) induce 15-PGDH in a TGF-b-dependent manner, b) restore expression of 15-PGDH in a model of colitis associated colon cancer and c) prevent clinical symptoms of IBD in this model. The observations outlined above are the basis for our hypothesis that colon cancer chemoprevention by triterpenoids requires a TGF-b-dependent induction of 15- PGDH.

描述（由申请人提供）：环氧合酶途径被认为是癌症化学预防和治疗的重要目标。前列腺素（PG）降解酶15-羟基丙烷蛋白脱氢酶（15-PGDH）作为结肠COX-C-2途径的内源性抑制剂，作为结肠肿瘤抑制剂的内源性抑制剂。现在有积累的证据支持以下假说：15-PGDH的表达在粘膜上皮稳态中起重要作用，而炎症介质对15-PDGH表达的抑制可能是结肠炎相关结肠癌的重要一步。特别是，最近的数据表明，在癌症化学预防的背景下，15-PGDH表达的丧失是对COX-2抑制剂反应的重要决定因素。因此，具有诱导15-PGDH表达能力的药物可以作为癌症化学预防的有效形式，并且可以增强对COX-2抑制剂（例如塞来氧化型或Celebrex（R））的抗反应或克服抗性。 15-PGDH在正常结肠粘膜中高度表达，但是该酶的表达总是在人类结肠癌中丧失。在小鼠中，编码15-PGDH的基因的破坏导致对结肠癌的易感性提高，从而增强了抗偶氮甲烷（AOM）的耐药性C57BL/6J菌株对结肠肿瘤诱导的敏感性，并导致apc+/min ne Min ne Mines NeyoplassIral neyoplassInal Neyop.trassiral neyop.trassical neyoplassiral neyoplassInal Neyop. 15-PGDH expression are not entirely clear, but a role for increased expression of histone deacetylase (HDAC) in human colon cancers in the repression of 15-PDGH expression has been demonstrated through a mechanism that involves the transcriptional repressor, Snail.5 In addition, repression of 15-PGDH by epidermal growth factor signaling and by inflammatory cytokines (TNF-a) has also been demonstrated.这些数据支持以下假设：炎症可能部分通过对前列腺素生物合成和代谢的酶的活性的协调作用来促进肿瘤发生。为了解决这个问题，我们的实验室现在探讨了三萜（自然和合成）诱导15-PGDH表达的能力，以及该酶的诱导是否与有效的结肠癌化学预防相关。三萜类化合物是一类多功能小分子，它们调节多个信号通路，并在特定的癌症临床前模型中表现出化学预防活性。我们的初步数据证明了三萜的能力：a）以TGF-B依赖性的方式诱导15-PGDH，b）在结肠炎相关的结肠癌模型中恢复15-PGDH的表达和C）在该模型中预防IBD的临床症状。上面概述的观察结果是我们假设的基础，即三萜类化结肠癌化学预防需要TGF-B依赖性诱导15-PGDH。