Role of Selenium in Cancer and Health

硒在癌症和健康中的作用

基本信息

批准号：
7592521
负责人：
Dolph Hatfield
金额：
$ 93.53万
依托单位：
DIVISION OF BASIC SCIENCES - NCI
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/7592521
关键词：
Acquired Immunodeficiency Syndrome Acute Age Aging-Related Process Amino Acids Animals Antioxidants Antiviral Agents Apoptosis Area Bone Marrow Cancer cell line Carcinogens Cardiovascular system Cell Line Cell physiology Cells Clinical Coagulative necrosis Colon Congresses Defect Development Diet Epidermis Excision Exhibits Genus Cola Growth HIV Seropositivity Health Health Benefit Heart Diseases Housing Human Hyperplasia Immunization In Vitro Incidence Indium Inflammatory Injection of therapeutic agent Interleukin-6 Knock-in Mouse Knock-out Knockout Mice Lipopolysaccharides Liver Longevity Lung Malignant Neoplasms Malignant neoplasm of liver Malignant neoplasm of lung Mammals Measurement Metabolism Micronutrients Modeling Molecular Mouse Cell Line Mus Myopathy National Cancer Institute Normal Cell Numbers Oncogenic Oral mucous membrane structure Organ Oxidoreductase Patients Phase Phosphorylation Production Property Prostate Protein Overexpression Proteins Publishing Rate Reporting Reproduction Research Role Role playing therapy Selenium Selenocysteine Serum Shock Siblings Signal Transduction Skin Source Staging T-Cell Proliferation T-Lymphocyte Techniques Technology Tissues Transgenic Organisms anticancer research cancer cell cancer prevention cancer therapy cost cytokine disorder prevention immune function in vivo knock-down liver cancer prevention macrophage male malignant phenotype mouse model novel prevent programs protein function response selenocysteine-tRNA selenoprotein thioredoxin reductase 1

项目摘要

Selenium is an essential micronutrient in the diet of humans and other mammals. It has many known health benefits such as preventing various forms of cancer (e.g., colon, prostate, lung and liver), preventing heart disease and other cardiovascular and muscle disorders, serving as an antiviral agent, and playing roles in delaying the aging process, delaying the progression of AIDS in HIV positive patients, in immune function, mammalian development and male reproduction. Even though many human clinical trails have been undertaken to elucidate the role of this element in cancer prevention, delaying the progression of AIDS, etc., at the cost of hundreds of millions of dollars, little is known about the mechanism of how selenium acts at the molecular level in exerting these many health benefits. We proposed that the health benefits are due largely to the presence of this element in selenoproteins as the selenium-containing amino acid, selenocysteine (Sec). Our program therefore focuses on 1) developing mouse models to assess the role of selenium and specific selenoproteins in human health and cancer prevention and 2) the means by which Sec is biosynthesized and incorporated into protein. The project discussed herein examines our research on the role of selenium in health and cancer prevention. During the past year, we finished and published our project on knocking down and knocking in selenoprotein expression providing an alternative and novel means of studying protein function. One of the selenoproteins we used as a model in developing this technique was thioredoxin reductase 1 (TR1). Since TR1 is overexpressed in many cancer cells, and since this selenium-containing oxidoreductase has been proposed to be a target for cancer therapy, we knocked down its expression in a mouse lung cancer cell line (LLC1) and reported that most of the malignant phenotypes were reversed more towards those of normal cells. These studies have been expanded to show that the malignant phenotypes of numerous human and mouse cell lines can also be altered by TR1 knockdown yielding a similar cancer inhibitory effect. We obtained an oncogenic, Ras overexpressing cell line from NIH3T3 cells and knocked down TR1 to analyze the underlying mechanism of the resulting growth inhibitory properties and found that the cells had a defect in the S phase. We are currently examining the precise mechanism for this inhibition. In addition, during the last few years, we have developed several transgenic, knockout, conditional knockout and knockdown cell and mouse lines that perturb Sec tRNA synthesis which in turn modulate selenoprotein expression as models to better understand selenium and selenoprotein metabolism and their roles in health. Using loxP-Cre technology, we have targeted the removal of selenoprotein expression in several tissues and organs. One of our major focuses in this area has recently been on the role of selenoproteins in immune function and skin cell function. We targeted the removal of selenoprotein expression in T-cells and in macrophages to investigate immune function and in mouse epidermis to investigate skin cell function. We previously found that T cells deficient in selenoproteins exhibit defective T cell proliferation, phosphorylation of ERK1/2, IL2Rα expression and an increased rate of apoptosis. This past year we completed in vivo immunization studies, measurement of ROS production and rescuing the defective proliferation. In vivo challenging studies showed that T cell selenoprotein deficient mice are immuno-compromised as the knockout mice exhibit significantly lower levels of various Igs upon challenging compared to sibling, wild type controls. The defective T cells were also found to generate and accumulate higher amounts of ROS upon stimulation; and upon using an external source of antioxidant, defective T cell proliferation was completely rescued. Removal of selenoproteins in macrophages showed an accumulation of ROS in unstimulated selenoprotein KO macrophages compared to wild type controls. Cytokine analysis of bone marrow-derived macrophages following in vitro stimulation with lipopolysaccharide (LPS) showed a decrease in IL-6 and TNF-α production while in vivo serum cytokine analysis appeared to show a significant increase in TNF-α production following injection with LPS. However, an in vivo challenge with LPS showed no significant difference in LPS-induced lethal shock between KO and control mice. An examination of the LPS-induced pro-inflammatory signaling cascade is currently being investigated. In our skin selenoproteinless mice, the animals exhibited stunted growth, which became more prominent with age, and they have a much shorter life span as compared to normal littermates. The knockout mice have flakiness and multiple wrinkles in skin, and pathological analysis revealed moderate epidermal hyperplasia along with acute coagulative necrosis of the epidermis and oral mucosa. We recently initiated a liver cancer study to examine the role of selenoproteins in liver cancer prevention. This study was undertaken as an extension of our previous finding that mice survive with the complete removal of selenoproteins in their liver and in response to the request by both houses of the US Congress that the National Cancer Institute should devote more effort to liver cancer research as the increased incidence of liver cancer and the small number of effective treatments is in sharp contrast to many other forms of cancer where the incidence is declining and the treatment options are rapidly increasing. These studies are in the early stages and we are examining the response of the selnoproteinless mice to carcinogens

硒是人类和其他哺乳动物饮食中必不可少的微量营养素。它具有许多已知的健康益处，例如预防各种形式的癌症（例如结肠，前列腺，肺和肝脏），预防心脏病和其他心血管疾病和其他心血管疾病，作为抗病毒药剂，并在延迟衰老过程中发挥作用，延迟艾滋病阳性患者的艾滋病进展，延迟免疫功能，男性乳房，男性乳房，男性重复，并恢复过。即使已经进行了许多人类的临床步道，以阐明该元素在预防癌症中的作用，延迟艾滋病的发展等，以数亿美元的成本，但对硒在分子水平上如何在施加这些许多健康益处方面的作用的机制知之甚少。我们提出，健康益处在很大程度上是由于该元素在硒蛋白中作为含硒的氨基酸硒代半胱氨酸（SEC）的存在。因此，我们的程序着重于1）开发小鼠模型，以评估硒和特异性硒蛋白在人类健康和癌症预防中的作用； 2）SEC生物合成并纳入蛋白质的方法。本文讨论的项目研究了我们对硒在健康和癌症预防中的作用的研究。在过去的一年中，我们完成并发布了有关敲击和敲击硒蛋白表达的项目，提供了一种研究蛋白质功能的替代和新颖的方法。我们用作开发该技术的模型的硒蛋白之一是硫氧还蛋白还原酶1（TR1）。由于TR1在许多癌细胞中都过表达，并且由于已提出这种含硒的氧化还原酶是癌症治疗的靶标，因此我们击倒了其在小鼠肺癌细胞系（LLC1）中的表达，并报道大多数恶性表型越来越多地逆转正常细胞的恶性表型。这些研究已经扩展，以表明许多人和小鼠细胞系的恶性表型也可以通过TR1敲低改变，从而产生类似的癌症抑制作用。我们从NIH3T3细胞中获得了过度表达的致癌性RAS，并击倒TR1以分析所得生长抑制特性的潜在机制，并发现细胞在S相中具有缺陷。我们目前正在研究这种抑制的确切机制。此外，在过去的几年中，我们开发了几种转基因，敲除，有条件的敲除和敲除细胞和小鼠系，这些细胞和小鼠系的sec tRNA合成反过来又调节了硒蛋白的表达，作为模型，以更好地了解硒和硒蛋白代谢及其在健康中的作用。使用LOXP-CRE技术，我们针对的是在几个组织和器官中去除硒蛋白的表达。最近，我们在该领域的主要重点之一是硒蛋白在免疫功能和皮肤细胞功能中的作用。我们针对T细胞和巨噬细胞中硒蛋白表达的去除，以研究免疫功能和小鼠表皮中以研究皮肤细胞功能。我们先前发现缺乏硒蛋白的T细胞表现出缺陷的T细胞增殖，ERK1/2的磷酸化，IL2Rα表达和凋亡率的增加。在过去的一年中，我们完成了体内免疫研究，ROS产生的测量以及挽救缺陷的增殖。体内挑战性的研究表明，与同胞，野生型对照相比，敲除小鼠在具有挑战性时表现出各种Ig的水平明显较低，因此T细胞硒蛋白缺乏的小鼠被免疫受损。还发现有缺陷的T细胞在刺激时会产生并积累更高量的ROS。并使用抗氧化剂的外部来源后，完全救出了T细胞增殖缺陷。与野生型对照相比，巨噬细胞中硒蛋白的去除表明ROS在未刺激的硒蛋白KO巨噬细胞中积累。脂多糖（LPS）体外刺激后骨髓来源的巨噬细胞的细胞因子分析显示，IL-6和TNF-α产生降低，而体内血清细胞因子分析似乎显示出在LPS注入后TNF-α产生的显着增加。然而，对LPS的体内挑战显示LPS诱导的KO和对照小鼠之间的致命休克没有显着差异。目前正在研究对LPS诱导的促炎信号级联反应的检查。在我们的皮肤无硒蛋白小鼠中，这些动物表现出发育迟缓的生长，随着年龄的增长而变得更加突出，与正常同窝仔相比，它们的寿命更短。敲除小鼠在皮肤中具有片状和多个皱纹，病理分析显示表皮和口服粘膜的急性表皮增生以及急性凝结坏死。我们最近开始了一项肝癌研究，以检查硒蛋白在肝癌预防中的作用。这项研究的扩展是我们先前的发现，即小鼠在肝脏中完全去除硒蛋白，并回应美国国会两院的要求，即国家癌症研究所应为肝癌进行更多的努力，因为肝癌的发病率增加，有效的治疗量很小，而其他癌症的治疗却差异很大，而癌症的差异很大，并且造成了巨大的治疗。这些研究处于早期阶段，我们正在检查硒蛋白小鼠对致癌物的反应