Role of IPMK in generation of small intestinal carcinoid

IPMK在小肠类癌生成中的作用

基本信息

批准号：
10630648
负责人：
Prasun Guha
金额：
$ 35.67万
依托单位：
UNIVERSITY OF NEVADA LAS VEGAS
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-06-01 至 2025-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10630648
关键词：
Affect Amino Acids Apoptosis Base Pairing Binding Sites Biochemical Biological C-terminal Carcinoid Tumor Cell Cycle Arrest Cell Cycle Regulation Cell Nucleus Cell Proliferation Cells Centers of Research Excellence Clinical Cre lox recombination system Deletion Mutation Development Enzymes Epithelial Cells Exhibits Gene Dosage Generations Genes Genetic Genetic Transcription Homo Impairment Inositol Intestinal Cancer Intestinal Neuroendocrine Neoplasm Knockout Mice Length Link Malignant Neoplasms Mammalian Cell Mediating Molecular Mus Mutation Nevada Nuclear Nuclear Localization Signal Operative Surgical Procedures Pathway interactions Patients Phosphotransferases Primary Neoplasm Prognosis Proteins Reporting Role Serotonin Signal Transduction Small Intestines TP53 gene advanced disease age related common treatment inositol polyphosphate multikinase intestinal epithelium intestinal homeostasis loss of function mutant personalized medicine tumor

项目摘要

Serotonin secreting small intestinal neuroendocrine tumors (SI-NET) are primary malignancies of the small bowel. When clinically recognized, afflicted patients often present with advanced disease and a poor 5-year prognosis (~36%). Surgery is the most common treatment of SI-NET. The genetic basis of Familial SI-NET is distinct from sporadic SI-NET. The only reported mutation linked to familial SI-NET is four base pair deletion mutations in the IPMK (Inositol polyphosphate multikinase) gene. IPMK protein is 416 amino acids in length,and the mutation truncates it to 333, eliminating the C-terminal ATP binding site and partial nuclear localization signal. IPMK heterozygous mutation exhibits a reduction of its kinase activity and nuclear localization. IPMK is the rate-limiting enzyme in the higher-order inositol synthesis pathway and generates inositol penta-phosphate. In mammalian cells, IPMK also acts as a PI3kinase. IPMK is primarily enriched in the nucleus, and loss of function of IPMK impairs p53 mediated transcription. As loss of p53 function is highly linked to several intestinal cancers, we like to investigate the importance of IPMK mutant (found in SI-NET patients) in p53 mediated apoptosis or cell cycle arrest in the origination of malignancies and tumor formation. How, homozygous loss of function of IPMK and a heterozygous mutant form of IPMK impair p53 mediated apoptosis and cell cycle arrest is entirely unknown and worth investigating to understand the molecular mechanism of SI-NET origination. Using Cre-Lox technology, we developed an intestinal epithelial cell-specific IPMK conditional homo and heterozygous KO mouse to understand the mechanism of IPMK mediated SI-NET development. We propose three specific aims—Aim 1. Determine how IPMK gene dosage affects the extent of SI-NET in mice. The histo-pathological, immuno-histochemical, and biochemical analysis will be performed to understand how hetero and homozygous loss of IPMK affects intestinal homeostasis and the extent of SI-NET generation in an age dependent manner. Aim 2. To determine if IPMK is necessary and sufficient to enhance cell proliferation and cell cycle regulation. Cell biological and flow-cytometric analysis will be performed to understand the critical function of IPMK in regulating cell proliferation and apoptosis. Aim 3. Determine if p53 is necessary for IPMK signaling-induced apoptosis and cell cycle arrest.

分泌血清素的小肠神经内分泌肿瘤（SI-NET）是原发性恶性肿瘤当临床上发现时，受影响的患者经常出现晚期疾病和症状。 5 年预后较差（~36%）。 SI-NET 最常见的治疗方法是遗传基础。家族性 SI-NET 与散发性 SI-NET 不同，唯一报道的与家族性 SI-NET 相关的突变是。 IPMK（肌醇多磷酸激酶）基因有四个碱基对缺失突变。长度为 416 个氨基酸，突变将其截短为 333 个，消除了 C 端 ATP 结合位点 IPMK杂合突变表现出其激酶的减少。 IPMK 是高阶肌醇合成中的限速酶。在哺乳动物细胞中，IPMK 还充当 PI3 激酶。 IPMK 主要富集于细胞核，IPMK 功能丧失会损害 p53 介导的功能由于 p53 功能的丧失与多种肠癌密切相关，因此我们希望进行研究。 IPMK 突变体（在 SI-NET 患者中发现）在 p53 介导的细胞凋亡或细胞周期停滞中的重要性在恶性肿瘤的起源和肿瘤形成中，IPMK和a的功能纯合性丧失。 IPMK 的杂合突变形式会损害 p53 介导的细胞凋亡和细胞周期停滞未知且值得研究以了解 SI-NET 起源的分子机制。 Cre-Lox技术，我们开发了肠上皮细胞特异性IPMK条件同源和我们使用杂合 KO 小鼠来了解 IPMK 介导的 SI-NET 发育机制。提出三个具体目标——目标 1. 确定 IPMK 基因剂量如何影响 SI-NET 的程度对小鼠进行组织病理学、免疫组织化学和生化分析。了解 IPMK 的杂合和纯合缺失如何影响肠道稳态以及影响程度 SI-NET 以年龄相关方式生成目标 2. 确定 IPMK 是否必要且充分。增强细胞增殖和细胞周期调节。细胞生物学和流式细胞术分析。目的是了解 IPMK 在调节细胞增殖和凋亡中的关键功能。确定 p53 是否是 IPMK 信号诱导的细胞凋亡和细胞周期停滞所必需的。