Interaction of statins with the proteasome/breast cancer

他汀类药物与蛋白酶体/乳腺癌的相互作用

• 批准号: 6867948
• 负责人: Ekem T Efuet
• 金额: $ 13.61万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-05-01 至 2010-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6867948
• 关键词: HMG coA reductases; RNA interference; SDS polyacrylamide gel electrophoresis; alkyltransferase; breast neoplasms; cell cycle proteins; cell growth regulation; cell line; chemical kinetics; cyclin dependent kinase; drug interactions; enzyme inhibitors; flow cytometry; gene induction /repression; geranyl compound; high performance liquid chromatography; human tissue; lactones; lovastatin; oncoprotein p21; proteasome; protein kinase; transfection /expression vector; ubiquitin; western blottings; HMG coA reductases; RNA interference; SDS polyacrylamide gel electrophoresis; alkyltransferase; breast neoplasms; cell cycle proteins; cell growth regulation; cell line; chemical kinetics; cyclin dependent kinase; drug interactions; enzyme inhibitors; flow cytometry; gene induction /repression; geranyl compound; high performance liquid chromatography; human tissue; lactones; lovastatin; oncoprotein p21; proteasome; protein kinase; transfection /expression vector; ubiquitin; western blottings

DESCRIPTION (provided by applicant): The goal of this study is to investigate the mechanisms by which statins inhibit a novel target, the proteasome, and how such inhibition leads to cell cycle arrest. Statins such as Lovastatin are widely used in the treatment of high blood cholesterol by inhibiting HMG-COA Reductase the enzyme responsible for the conversion of HMG-COA to mevalonate, the rate limiting enzyme in cholesterol biosynthesis. We propose a new mechanism of interaction for the non lipid-related effects of Lovastatin whereby it inhibits the proteasome, upregulates cyclin dependent kinase inhibitors (CKI) and leads to cell cycle arrest. In support of this novel mechanism, we provide experimental evidence that drug treated cells undergo changes characteristic of proteasome inhibition and cell arrest. We show that upon treating cells with Lovastatin, they arrest in the G1 phase of the cell cycle, as indicated by FACS analysis. Western blot analysis shows upregulation of p21 and p27 leading to the inhibition of the CDK2 kinase activity. In vitro proteasome activity assay utilizing the prodrug form of Lovastatin inhibits the proteasome activity in a dose dependent fashion reminescent of the effects of the well characterized proteasome inhibitors such as lactacystin and MG-132. Lastly, agents possessing a lactone moiety, including inhibitors of downstream enzymes in the cholesterol biosynthesis pathway such as farnesyl transferase and geranyl geranyl transferase inhibitors (i.e. FTI-277 and GGTI-298), also block the proteasome activity in a concentration dependent manner. In this career development award, I propose to investigate how the drugs Lovastatin, structurally similar to inhibitors such as GGTI-298 and FTI-277 and lactacystin cause CKI induction and whether their paths intercept. I suspect that they do since both lactacystin and Lovastatin like agents inhibit the proteasome; both class of agents induce the CKIs similarly. I have 3 aims: 1) Determine if the accumulation of p21 and/or p27 resulting from Lovastatin treatment is sufficient to lead to G1 cell arrest in cultured cells by developing/using model systems devoid of p21, p27 or both. 2) Characterize the biochemical interaction of Lovastatin with the proteasome and determine how such interaction (s) cause an increase in p21 and p27 in breast tumor cells.3) Define the generality of lactone containing farnesyl, and geranylgeranly transferase inhibitors that account for their dual mode of action in the cholesterol biosynthesis vs the proteasome proteolytic pathway. The proposed project will contribute to the understanding of this novel action of statins, by helping to elucidate the mechanism of interaction of Lovastatin with the proteasome.

描述（由申请人提供）：这项研究的目的是研究他汀类药物抑制新型靶标，蛋白酶体以及这种抑制如何导致细胞周期停滞的机制。他汀类药物（例如洛伐他汀）通过抑制HMG-COA还原酶的酶来治疗高血胆固醇，该酶负责将HMG-COA转化为甲谷酸盐，该酶限制了胆固醇生物合成的酶。我们提出了一种新的相互作用机制，用于洛伐他汀的非脂质相关作用，从而抑制蛋白酶体，上调细胞周期蛋白依赖性激酶抑制剂（CKI）并导致细胞周期停滞。为了支持这种新型机制，我们提供了实验证据，表明药物处理的细胞经历了蛋白酶体抑制和细胞停滞的特征。我们表明，在用洛伐他汀治疗细胞后，它们会在细胞周期的G1阶段停滞，如FACS分析所示。蛋白质印迹分析表明，p21和p27的上调导致抑制CDK2激酶活性。利用lovastatin的前药形式的体外蛋白酶体活性测定，以剂量依赖性的方式抑制蛋白酶体活性，以使表征良好的蛋白酶体抑制剂（如乳酸和MG-132）的作用重新发明。最后，具有内酯部分的药物，包括胆固醇生物合成途径中下游酶的抑制剂，例如法汀基转移酶和香烷基甘烷基转移酶抑制剂（即FTI-277和GGTI-298），也阻止了浓度依赖性的蛋白酶体活动。在这个职业发展奖中，我建议研究lovastatin在结构上类似于GGTI-298和FTI-277等抑制剂的药物以及乳酸如何引起CKI诱导以及它们的道路是否截断。我怀疑他们这样做是因为乳酸和洛伐他汀都像剂一样抑制蛋白酶体。两类代理都同样诱导CKIS。我有3个目的：1）确定lovastatin治疗引起的P21和/或P27的积累是否足以通过开发/使用没有P21，P27或两者兼有的模型系统来导致培养细胞中的G1细胞停滞。 2）表征洛伐他汀与蛋白酶体的生化相互作用，并确定这种相互作用是如何导致乳腺肿瘤细胞中p21和p27的增加的。拟议的项目将通过帮助阐明洛伐他汀与蛋白酶体的相互作用机理，从而有助于对他汀类药物的这种新作用的理解。