Hypersensitivity of Multiple Myeloma Bone Disease to Vitamin D

多发性骨髓瘤骨病对维生素 D 过敏

基本信息

批准号：
8570680
负责人：
Garson DAVID ROODMAN
金额：
$ 16.97万
依托单位：
INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-07-19 至 2015-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8570680
关键词：
1,25 (OH) vitamin D 25-hydroxyvitamin D Affect Antibodies Binding Biological Biological Assay Bone Diseases Bone Marrow Bone neoplasms Cancer Patient Cell Adhesion Cell Differentiation process Cell Line Cell Proliferation Cells Co-Immunoprecipitations Complex Conditioned Culture Media Data Development Distal Enhancers Future Genes Genetic Transcription Goals Half-Life Homeostasis Human Hypersensitivity IL6 gene Immunocompromised Host Marrow Mediating Mixed Function Oxygenases Molecular Morbidity - disease rate Multiple Myeloma Mus Normal Cell Normal Range Osteitis Deformans Osteoclasts Osteolytic Patients Pharmaceutical Preparations Physiological Pike fish Plasma Cells Play Production Regulation Role SCID Mice Sampling Serum Signal Pathway Signal Transduction Solid Neoplasm Stromal Cells Stromal Neoplasm T-Lymphocyte TAF12 gene TNF gene TNFSF11 gene Testing Therapeutic Intervention Time Toxic effect Tumor Burden Vitamin D Vitamin D Analog Vitamin D Deficiency Vitamin D3 Receptor Vitamins Western Blotting bone bone cell chromatin immunoprecipitation cytokine in vivo inhibitor/antagonist loss of function mortality mouse model neoplastic cell novel overexpression promoter public health relevance receptor receptor binding research study response restoration skeletal small hairpin RNA small molecule therapeutic target transcription factor tumor tumor growth

项目摘要

DESCRIPTION (provided by applicant): Osteolytic bone disease is a major contributor to the morbidity and mortality caused by incurable multiple myeloma (MM). Active 1,25-dihydroxyvitamin D (1,25-(OH)2D) stimulates both tumor & bone cells, contributing to myeloma bone disease (MBD), despite vitamin D insufficiency in the majority of MM patients. This continuing function of vitamin D signaling in MBD is due to hypersensitivity of specific gene promoters in both tumor cells & bone cells to unusually low concentrations (10-11-10-10M) of 1,25-(OH)2D. Extensive preliminary data support a novel mechanism of action of 1,25-(OH)2D in MBD: Both tumor cells and bone cells are hypersensitized to 1,25-(OH)2D by overexpression of the transcriptional activating factor TAF12. At very low levels of expression in normal cells, TAF12 functions as a widely expressed, conventional transcription factor complex component, but when overexpressed it binds at vitamin D receptor (VDR)- responsive promoters and functions as a novel VDR co-activator. TAF12 was strongly overexpressed in 5/8 primary MM samples, while TAF12 gain and loss of function respectively increased and decreased sensitivity of specific transcription to 1,25-(OH)2D. Additional vitamin D hypersensitivity may be due to binding of ATF7 (also overexpressed in MM) to TAF12 & frequent loss of the VDR co-repressor SMRT (NCoR2) from MM cells. AIM 1 will investigate the biological responses of myeloma & marrow stromal cells to low concentrations of 1,25-(OH)2D by assaying MM cell proliferation, MM-stromal cell adhesion, cytokine production & support of osteoclast formation. We will test whether ATF7 is consistently overexpressed in primary MM cells and if it occurs in concert with TAF12. The mechanism by which TAF12 expression is increased will also be investigated and may be caused by increased IL6 & TNF¿ in the marrow microenvironment. AIM 2 will characterize the molecular mechanisms of vitamin D hypersensitivity in tumor & bone stromal cells, including assembly of TAF12 & TAF12:ATF7 complexes on two vitamin D-responsive promoters, assayed by chromatin immunoprecipitation The effects of TAF12 & TAF12:ATF7 on VDR protein half-life in response to 1,25-(OH)2D will be determined in MM and bone stromal cells, as will the ability of the co-repressor SMRT to reverse hypersensitivity to 1,25-(OH)2D. In Year 2, AIM 3 will test TAF12 as a therapeutic target in myeloma. MM cells with TAF12 gain or loss of function will be grown in an immunocompromised mouse model of osteolytic MBD to determine the effects on tumor burden and bone destruction. The goal is to demonstrate the utility of TAF12 as an important regulator of MBD, since co-activator:VDR binding interactions are druggable with small molecules. Such novel agents could selectively and effectively target the pathological responses to 1,25-(OH)2D of tumor cells and bone cells in myeloma bone disease, without the systemic toxicities caused by vitamin D antagonists.

描述（由适用提供）：骨化骨病是导致无法治愈的多发性骨髓瘤（MM）引起的发病率和死亡率的主要因素。活跃的1,25-二羟基维生素D（1,25-（OH）2d）刺激肿瘤和骨细胞，导致大多数MM患者的骨髓瘤骨病（MBD），dospite维生素D不足。维生素D信号在MBD中的这种持续功能是由于特定基因启动子在肿瘤细胞和骨细胞中的特定基因启动子的过敏性引起的，其浓度很少（10-11-10-10m）为1,25-（OH）2d。广泛的初步数据支持MBD中1,25-（OH）2D的新型作用机理：肿瘤细胞和骨细胞均通过过度表达转录激活因子TAF12而对1,25-（OH）2D敏感。在正常细胞的表达水平非常低时，TAF12充当广泛表达的常规转录因子复合成分，但是当过表达时，它在维生素D受体（VDR）（VDR）上结合 - 响应启动子，并且是一种新型的VDR共激活剂。 TAF12在5/8主要MM样品中强烈表达，而TAF12的增益和功能损失分别增加了特定转录对1,25-（OH）2D的敏感性。额外的维生素D超敏反应可能是由于ATF7（也以MM的过表达）与TAF12的结合，并且经常损失MM细胞中VDR共阻剂SMRT（NCOR2）。 AIM 1通过测定MM细胞增殖，MM粘液细胞粘附，细胞因子的产生和骨细胞形成的支持，研究骨髓瘤和骨髓基质细胞对1,25-（OH）2D的生物学反应。我们将测试ATF7在原代MM细胞中是否持续过表达，并且是否与TAF12一起发生。 TAF12表达增加的机制也将受到研究，可能是由于骨髓微环境中IL6＆TNF的增加而引起的。 AIM 2 will characterize the molecular mechanisms of vitamin D hypersensitivity in tumor & bone stromal cells, including assembly of TAF12 & TAF12:ATF7 complexes on two vitamin D-responsive promoters, assigned by chromatin immunoprecipitation The effects of TAF12 & TAF12:ATF7 on VDR protein half-life in response to 1,25-(OH)2D will be determined in MM和骨基质细胞，共抑制器SMRT将超敏反应逆转至1,25-（OH）2d的能力也是如此。在第二年，AIM 3将测试TAF12作为骨髓瘤的治疗靶点。具有TAF12增益或功能损失的MM细胞将在骨化溶液MBD的免疫功能低下的小鼠模型中生长，以确定对肿瘤烧伤和骨骼破坏的影响。目的是证明TAF12作为MBD的重要调节剂的实用性，因为共激活剂：VDR结合相互作用可与小分子吸毒。这种新型药物可以选择性有效地靶向对骨髓瘤骨骼疾病中1,25-（OH）2D肿瘤细胞和骨细胞的病理反应，而没有由维生素D拮抗剂引起的全身毒性。