DIFFERENTIAL GENE REGULATION IN NORMAL & TRANSFORMED KERATINOCYTES BY 1,25(OH)2

正常情况下的差异基因调控

• 批准号: 8363736
• 负责人: DANIEL David BIKLE
• 金额: $ 0.01万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-01 至 2012-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8363736
• 关键词: Binding; Cell Line; Complex; DNA Sequence; Funding; Gene Expression; Gene Expression Regulation; Genes; Genetic Transcription; Grant; Human; Ligands; Link; Malignant Neoplasms; Mass Spectrum Analysis; Mediating; National Center for Research Resources; Nuclear Extract; Nuclear Hormone Receptors; Prevention; Principal Investigator; Proteins; RNA Polymerase II; RXR; Recruitment Activity; Research; Research Infrastructure; Resources; Response Elements; Source; Squamous cell carcinoma; Steroid Receptors; Thyroid Gland; Transcription Initiation; Tretinoin; Undifferentiated; United States National Institutes of Health; VDR interacting protein complex DRIP; Vitamin A; Vitamin D; Vitamin D Response Element; cofactor; cost; hormone response element; keratinocyte; keratinocyte differentiation; promoter; receptor; receptor binding; response

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The active metabolites of vitamin D and vitamin A show promise in the prevention and treatment of a number of malignancies including squamous cell carcinoma (SCC). 1,25(OH)2D regulates gene expression through its nuclear hormone receptor VDR. VDR partners with the retinoic X (RXR) and retinoic acid (RAR) receptors which bind the active metabolites of vitamin A, 9cis retinoic acid (9cisRA) and all trans retinoic acid (tRA), respectively. VDR, RXR, and RAR form heterodimers, which stimulate gene expression through specific sequences of DNA in the promoter of genes called hormone response elements. Different vitamin D responsive genes have different response elements and are differentially regulated by 1,25(OH)2D and RA in normal human keratinocytes (NHK). Squamous carcinoma cell lines (SCC) fail to respond to 1,25(OH)2D or RA in the same manner as NHK. The SCC lines we have studied have normal levels of VDR with normal binding of the VDR to its ligand and normal binding of the VDR to the vitamin D response elements (VDRE). Therefore, the explanation for the loss of response of SCC to 1,25(OH)2D has been unclear. However, it has recently been discovered that nuclear hormone receptors such as VDR, RAR, and RXR interact with a number of coactivators and cosuppressors which link the nuclear hormone receptors bound to their respective response elements to the transcription initiation complex where transcription by RNA polymerase II begins. During the previous funding period we discovered that the principal binding complex to VDR in nuclear extracts from undifferentiated normal keratinocytes is DRIP (vitamin D receptor interacting protein), a complex essentially identical to TRAP (thyroid receptor activating protein) and ARC (activator-recruited cofactor) which were identified by their binding to other nuclear hormone receptors. During normal keratinocyte differentiation DRIP is downregulated. Its binding to VDR is replaced by two SRC (steroid receptor coactivator). More recently we found that hairless acts as a suppressor of VDR action. We are currently involved in determining the factors that mediate this suppressor action of hairless on VDR.

该子项目是利用资源的众多研究子项目之一 由 NIH/NCRR 资助的中心拨款提供。子项目的主要支持 并且子项目的首席研究员可能是由其他来源提供的， 包括其他 NIH 来源。 子项目可能列出的总成本 代表子项目使用的中心基础设施的估计数量， NCRR 赠款不直接向子项目或子项目工作人员提供资金。 维生素 D 和维生素 A 的活性代谢物有望预防和治疗包括鳞状细胞癌 (SCC) 在内的多种恶性肿瘤。 1,25(OH)2D 通过其核激素受体 VDR 调节基因表达。 VDR 与视黄酸 X (RXR) 和视黄酸 (RAR) 受体结合，分别结合维生素 A、9顺式视黄酸 (9cisRA) 和全反式视黄酸 (tRA) 的活性代谢物。 VDR、RXR 和 RAR 形成异二聚体，通过称为激素反应元件的基因启动子中的特定 DNA 序列刺激基因表达。 正常人角质形成细胞 (NHK) 中，不同的维生素 D 响应基因具有不同的响应元件，并受 1,25(OH)2D 和 RA 的差异调节。鳞状癌细胞系 (SCC) 无法以与 NHK 相同的方式对 1,25(OH)2D 或 RA 做出反应。 我们研究的 SCC 系具有正常水平的 VDR，VDR 与其配体的正常结合以及 VDR 与其维生素 D 反应元件 (VDRE) 的正常结合。因此，SCC 对 1,25(OH)2D 失去反应的解释尚不清楚。 然而，最近发现核激素受体如VDR、RAR和RXR与许多共激活子和共抑制子相互作用，这些共激活子和共抑制子将与其各自反应元件结合的核激素受体与转录起始复合物连接起来，其中RNA聚合酶II进行转录开始。 在之前的资助期间，我们发现未分化正常角质形成细胞核提取物中与 VDR 的主要结合复合物是 DRIP（维生素 D 受体相互作用蛋白），该复合物与 TRAP（甲状腺受体激活蛋白）和 ARC（激活剂招募辅因子）基本相同）通过与其他核激素受体的结合来识别。 在正常角质形成细胞分化过程中，DRIP 下调。 它与 VDR 的结合被两个 SRC（类固醇受体共激活剂）取代。 最近我们发现无毛可以抑制 VDR 的作用。 我们目前正在参与确定介导无毛对 VDR 抑制作用的因素。