Therapeutic targeting of stratifin structure and function

描述（由申请人提供）：缺乏对化疗和/或辐射诱导的细胞凋亡的反应是成功治疗人类癌症（如胰腺癌）的主要问题。最近，我们发现在一系列对药物诱导的凋亡不敏感的药物选择癌细胞中，stratifin的表达升高，并且其表达水平与这些细胞的药物敏感水平呈负相关。shRNA敲低和stratifin强制异位表达均证实了stratifin表达与药物不敏感之间的因果关系。我们研究的长期目标是了解药物和/或辐射诱导胰腺癌细胞凋亡的分子机制，并使癌细胞对这些治疗诱导的细胞凋亡敏感。本研究的直接目标是研究分层芬在细胞对药物或辐射诱导的细胞凋亡反应中的作用，并将分层芬作为药物发现的靶点，以增强胰腺癌细胞对治疗的反应。本研究需要验证的假设是，胰腺癌细胞中升高的stratifin表达通过结合和影响重要的生存蛋白，降低了细胞对药物或辐射诱导的凋亡的反应，这种作用可以通过使用小分子抑制剂靶向stratifin来逆转。为此，将实现四个具体目标：(1)确定层析蛋白表达的增加是否也会导致细胞对辐射诱导的凋亡的反应降低；(2)确定增加的stratifin表达是否调节Chk2， Chk2反过来调节DNA修复和存活的细胞周期检查点；(3)确定二聚化的机理，以及是否需要二聚化才能起到分层作用；(4)发现并测试靶向分层二聚化的化学致敏小化合物。印第安纳大学布伦和梅尔文西蒙癌症中心优秀的科学环境，首席研究员在研究药物诱导细胞凋亡的细胞反应方面的丰富经验，以及慷慨的机构支持，将极大地促进该项目成功的可能性。本研究获得的信息和探针将有助于我们了解分层芬在癌症化疗中凋亡中的作用。这项工作还将引导我们发现可能有助于使癌症对药物和放射治疗敏感的治疗药物，以及用于研究蛋白质-蛋白质相互作用的探针。

DESCRIPTION (provided by applicant): Lack of response to chemo and/or radiation-induced apoptosis is a major problem for successful therapy of human cancers such as pancreatic cancer. Recently, we found that the expression of stratifin is elevated in a series of drug-selected cancer cell lines that are less sensitive to drug-induced apoptosis and its expression level negatively correlates with the drug sensitivity level of these cells. Knocking-down with shRNA and enforced ectopic expression of stratifin both confirmed the cause-effect relationship between stratifin expression and drug insensitivity. The long-term goal of our study is to understand the molecular mechanisms of drug and/or radiation-induced apoptosis in pancreatic cancers and to sensitize cancer cells to these treatment-induced apoptosis. The immediate goal of this study is to investigate the role of stratifin in cellular response to drug or radiation-induced apoptosis and to target stratifin for drug discovery to enhance the response of pancreatic cancer cells to therapeutic treatment. The hypotheses to be tested in this study are that the elevated expression of stratifin in pancreatic cancer cells decreases cellular response to drug or radiation-induced apoptosis by binding to and affecting important proteins for survival and that this effect can be reversed by targeting stratifin using small molecule inhibitors. To this end, four specific aims will be accomplished: (1) to determine if increased stratifin expression also causes decrease in cellular response to radiation-induced apoptosis; (2) to determine if increased stratifin expression regulates Chk2 which, in turn, regulates cell cycle checkpoint for DNA repair and survival; (3) to determine the mechanism of dimerization and if the dimerization is required for the function of stratifin; and (4) to discover and test small chemical compounds targeting stratifin dimerization for chemosensitization. The excellent scientific environment at Indiana University Bren and Melvin Simon Cancer Center, the extensive experience of the principal investigator in studying cellular responses to drug- induced apoptosis, and the generous institutional support will contribute enormously to the likelihood of success of this project. The information and probes obtained from this study will help us understand the role of stratifin in apoptosis in cancer chemotherapy. This work will also lead us to the discovery of therapeutic agents that may help sensitize cancers to drug and radiation therapy and probes for investigating protein-protein interactions. PUBLIC HEALTH RELEVANCE: Lack of response to chemo and radiation treatment-induced apoptosis is a major problem for successful chemotherapy of human pancreatic cancers. The long-term goal of our study is to understand the molecular mechanisms of drug and/or radiation-induced apoptosis in cancers and to sensitize cancer cells to these treatment-induced apoptosis. The hypotheses to be tested in this study are that the elevated expression of stratifin in pancreatic cancer cells decreases cellular response to drug or radiation-induced apoptosis by binding to and affecting important proteins for survival and that this effect can be reversed by targeting stratifin using small molecule inhibitors. To this end, four specific aims will be accomplished: (1) to determine if increased stratifin expression also causes decrease in cellular response to radiation-induced apoptosis; (2) to determine if increased stratifin expression regulates Chk2 which, in turn, regulates cell cycle checkpoint for DNA repair and survival; (3) to determine the mechanism of dimerization and if the dimerization is required for the function of stratifin; and (4) to discover and test small chemical compounds targeting stratifin dimerization for chemosensitization.