A Novel Ring Finger Protein in Cancer Drug Resistance

一种新型环指蛋白在癌症耐药性中的作用

• 批准号: 7024961
• 负责人: SUBRAHMANYESWARA U RAO
• 金额: $ 22.84万
• 依托单位: TEXAS TECH UNIVERSITY HEALTH SCIS CENTER
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7024961
• 关键词: CHO cells; DNA footprinting; MCF7 cell; P glycoprotein; RNA interference; adenosinetriphosphatase; breast neoplasms; cell membrane; chromatin immunoprecipitation; drug interactions; enzyme activity; flow cytometry; gel mobility shift assay; gene expression; genetic transcription; in situ hybridization; multidrug resistance; neoplasm /cancer chemotherapy; phosphorylation; polymerase chain reaction; prostate neoplasms; protein protein interaction; protein structure function; protein transport

DESCRIPTION (provided by applicant): During chemotherapy, many cancers develop multidrug resistance (MDR). One key protein underlying MDR is the MDR1-protein (commonly known as P-glycoprotein (Pgp)), which extrudes multiple drugs from the cancer cells utilizing ATP. The functional characteristics of Pgp have been extensively characterized. However, the mechanism by which anticancer drugs induce the expression of Pgp; the mechanism by which the activity of Pgp is regulated in cancers, are unknown. We have identified a new gene that codes for a (38 kDa RING finger protein, termed MDR1Pi. This protein is highly expressed in drug-resistant cancer cells. Anticancer drugs further increase the expression of this protein. Importantly, we show that MDR1Pi interacts with Pgp, specifically the linker region, which is known to join the NH2- and COOH-halves of Pgp. Interestingly, the linker region is shown to be important for the drug-transport and ATPase activities of Pgp. Thus, these findings suggest that MDR1Pi is an important protein, which regulates the Pgp function through its interactions with the linker region. Hence, our major interest is to provide a thorough understanding of MDR1Pi function in the development of MDR that will contribute to future therapeutic approaches to treat MDR cancers using MDR1Pi as a new molecular target. To this end, we will evaluate the function of MDR1Pi in breast and in prostate cancer cells. We have defined three specific objectives to address the functional role of MDR1Pi in the development of MDR, which are to: 1). determine the effects of MDR1Pi on the ATPase and drug transport functions of Pgp; 2). determine the role of MDR1Pi in the development of MDR; 3). determine the role of MDR1Pi in the MDR1 gene expression. In specific aim 1, we will measure and compare the drug transport and ATPase activities of Pgp and Pgp-MDR1Pi complex, to identify the role of MDR1Pi in the Pgp function. Specific aim 2 is designed to determine if MDR1Pi alone imparts MDR phenotype, by expressing MDR1Pi in drug-sensitive cells; and by silencing the expression of MDR1Pi in drug-resistant cells. We will also compare the expression patterns of MDR1Pi and Pgp to determine the functional relationship between MDR1Pi and Pgp. The specific aim 3 is designed to determine if MDR1Pi regulates the MDR1 gene transcription. We will also determine how the linker region and anticancer drugs modulate the MDR1Pi function in relation to MDR1 gene transcription. Characterization of MDR1Pi, the first known interactor of Pgp, will unravel the mechanisms by which the function and expression of Pgp are regulated. These data will be key to the future designs of re-sensitizing the anticancer drug-refractory cancers.

描述（由申请人提供）： 在化疗过程中，许多癌症产生多药耐药性（MDR）。MDR的一个关键蛋白是MDR 1蛋白（通常称为P-糖蛋白（Pgp）），它利用ATP从癌细胞中挤出多种药物。Pgp的功能特性已被广泛表征。然而，抗癌药物诱导Pgp表达的机制; Pgp活性在癌症中调节的机制尚不清楚。我们已经确定了一个新的基因，编码一个38 kDa的环指蛋白，称为MDR 1 Pi。这种蛋白质在耐药癌细胞中高度表达。抗癌药物进一步增加这种蛋白质的表达。重要的是，我们发现MDR 1 Pi与Pgp相互作用，特别是连接区，已知连接Pgp的NH 2-和COOH-半。有趣的是，连接区被证明是重要的药物转运和ATP酶活性的Pgp。因此，这些研究结果表明，MDR 1 Pi是一个重要的蛋白质，它通过与连接区的相互作用来调节Pgp的功能。因此，我们的主要兴趣是提供MDR 1 Pi在MDR发展中的功能的透彻理解，这将有助于未来使用MDR 1 Pi作为新的分子靶点治疗MDR癌症的治疗方法。为此，我们将评估MDR 1 Pi在乳腺癌和前列腺癌细胞中的功能。我们已经定义了三个具体目标，以解决MDR 1 Pi在MDR发展中的功能作用，即：1）。测定MDR 1 Pi对Pgp的ATP酶和药物转运功能的影响; 2）.确定MDR 1 Pi在MDR发生中的作用; 3）.确定MDR 1 Pi在MDR 1基因表达中的作用。在具体目标1中，我们将测量和比较Pgp和Pgp-MDR 1 Pi复合物的药物转运和ATP酶活性，以确定MDR 1 Pi在Pgp功能中的作用。具体目标2旨在通过在药物敏感细胞中表达MDR 1 Pi和通过在耐药细胞中沉默MDR 1 Pi的表达来确定单独MDR 1 Pi是否赋予MDR表型。我们还将比较MDR 1 Pi和Pgp的表达模式，以确定MDR 1 Pi和Pgp之间的功能关系。具体目标3是确定MDR 1 Pi是否调节MDR 1基因转录。我们还将确定连接区和抗癌药物如何调节MDR 1 Pi与MDR 1基因转录相关的功能。MDR 1 Pi是第一个已知的Pgp相互作用因子，其特征将揭示Pgp功能和表达的调控机制。这些数据将是未来抗癌药物难治性癌症再致敏设计的关键。