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）：在化学疗法期间，许多癌症会产生多药耐药性（MDR）。 MDR的一个关键蛋白是MDR1-蛋白质（通常称为P-糖蛋白（PGP）），它挤出了利用ATP的癌细胞中的多种药物。 PGP的功能特征已被广泛表征。但是，抗癌药物诱导PGP表达的机制； PGP在癌症中调节PGP活性的机制是未知的。我们已经确定了一个新基因，该基因代码为A（38 kDa环手指蛋白，称为MDR1PI。该蛋白在药物抗药性癌细胞中高度表达。抗癌药物进一步增加了该蛋白的表达。重要的是，重要的是，我们显示MDR1PI与PGP相互作用，该链接与链接区域相互作用，该区域与链接相互作用，并与PP相互作用。对于PGP的药物转移和ATPase活动很重要，这些发现表明，MDR1PI是一种重要的蛋白质，它通过其与接头区域的相互作用来调节PGP的功能，因此，我们的主要兴趣是对MDR在MDR中的彻底理解，这将为MOL1造成MOL1的贡献最后，我们将评估MDR1PI在乳腺癌和前列腺癌细胞中的功能。确定MDR1PI对PGP ATPase和药物转运函数的影响； 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。在特定的目标1中，我们将测量和比较PGP和PGP-MDR1PI复合物的药物转运和ATPase活性，以确定MDR1PI在PGP功能中的作用。特定的目标2旨在通过在药物敏感细胞中表达MDR1PI来确定单独MDR1PI是否赋予MDR表型。并通过沉默在耐药细胞中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。特定目标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根据MDR1基因转录调节MDR1PI的功能。 MDR1PI的表征是PGP的第一个已知相互作用者，将揭示PGP功能和表达的机制。这些数据将是重新敏感抗癌药物难治性癌症的未来设计的关键。