Role of IPMK in generation of small intestinal carcinoid

IPMK在小肠类癌生成中的作用

• 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
• 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

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.

5-羟色胺分泌性小肠神经内分泌肿瘤(SI-Net)是 小肠。当临床发现时，患者通常表现为晚期疾病和一种 5年预后较差(~36%)。手术是SI-Net最常见的治疗方法。的遗传基础 家族性SI-net不同于散发性SI-net。唯一报道的与家族性SI-Net有关的突变是 IPMK(肌醇多磷酸多激酶)基因的四个碱基缺失突变。IPMK蛋白是 416个氨基酸，突变将其截断为333个，消除了C-末端的ATP结合位点 和部分核定位信号。IPMK杂合突变表现出其激酶的降低 活动和核定位。IPMK是肌醇合成的限速酶 途径，并产生肌醇五磷酸。在哺乳动物细胞中，IPMK也扮演着PI3K的角色。 IPMK主要集中在细胞核内，IPMK功能丧失会损害P53介导的功能 抄写。由于P53功能的丧失与几种肠癌高度相关，我们愿意研究 IPMK突变(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的形成中起重要作用。如何，IPMK和a功能的纯合性丧失 IPMK杂合突变形式损伤P53介导的细胞凋亡和细胞周期完全停滞 尚不清楚，值得研究以了解SI-Net起源的分子机制。vbl.使用 Cre-Lox技术，我们开发了一种肠上皮细胞特异性的IPMK条件性HOMO和 了解IPMK介导SI-Net发育的机制。我们 提出三个具体的目标-目标1.确定IPMK基因剂量如何影响SI-Net的程度 老鼠。将进行组织病理学、免疫组织化学和生化分析 了解IPMK杂合性和纯合性丢失如何影响肠道内环境平衡以及 以年龄相关的方式生成硅网络。目标2.确定IPMK是否必要且充分 促进细胞增殖和细胞周期调节。细胞生物学和流式细胞术分析将是 目的：了解IPMK在调节细胞增殖和凋亡中的关键作用。目标3. 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。