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，许多癌症会产生多药耐药性（MDR）。 MDR 背后的一个关键蛋白是 MDR1 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 的功能特性已得到广泛表征。然而，抗癌药物诱导Pgp表达的机制； Pgp 活性在癌症中受到调节的机制尚不清楚。我们鉴定了一个编码 (38 kDa RING Finger) 蛋白的新基因，称为 MDR1Pi。该蛋白在耐药癌细胞中高度表达。抗癌药物进一步增加了该蛋白的表达。重要的是，我们表明 MDR1Pi 与Pgp，特别是接头区域，已知其连接 Pgp 的 NH2- 和 COOH- 部分。有趣的是，接头区域对于药物转运和 ATP 酶非常重要。因此，这些发现表明 MDR1Pi 是一种重要的蛋白质，通过其与接头区域的相互作用来调节 Pgp 功能。因此，我们的主要兴趣是全面了解 MDR1Pi 在 MDR 发展中的功能。为使用 MDR1Pi 作为新分子靶点治疗 MDR 癌症的未来治疗方法做出贡献 为此，我们将评估 MDR1Pi 在乳腺癌和前列腺癌细胞中的功能，我们确定了三个具体目标来解决其功能作用。 MDR1Pi在MDR开发中的作用，包括： 1).确定MDR1Pi对Pgp的ATP酶和药物转运功能的影响； 2）。确定 MDR1Pi 在 MDR 发展中的作用； 3）。确定 MDR1Pi 在 MDR1 基因表达中的作用。在具体目标1中，我们将测量并比较Pgp和Pgp-MDR1Pi复合物的药物转运和ATP酶活性，以确定MDR1Pi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 MDR1Pi 来确定 MDR1Pi 是否单独赋予 MDR 表型；以及通过沉默耐药细胞中 MDR1Pi 的表达。我们还将比较 MDR1Pi 和 Pgp 的表达模式，以确定 MDR1Pi 和 Pgp 之间的功能关系。具体目标3旨在确定MDR1Pi是否调节MDR1基因转录。我们还将确定接头区域和抗癌药物如何调节与 MDR1 基因转录相关的 MDR1Pi 功能。 MDR1Pi（第一个已知的 Pgp 相互作用因子）的表征将揭示 Pgp 功能和表达的调节机制。这些数据将成为未来设计对抗癌药物难治性癌症重新敏感的关键。