Flavopiridol Targets Transcription Factor/DNA Complexes

黄酮吡醇靶向转录因子/DNA 复合物

• 批准号: 6719610
• 负责人: KEITH C. BIBLE
• 金额: $ 29.24万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-03-14 至 2007-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6719610
• 关键词: DNA; DNA binding protein; DNA damage; DNA footprinting; affinity chromatography; antineoplastics; apoptosis; biological signal transduction; blood /lymphatic neoplasm; cell line; clinical research; cyclin dependent kinase; cytotoxicity; enzyme inhibitors; flavopiridol; gel mobility shift assay; human tissue; intermolecular interaction; microarray technology; molecular dynamics; natural killer cells; northern blottings; nuclear magnetic resonance spectroscopy; nuclear runoff assay; polymerase chain reaction; transcription factor; western blottings

DESCRIPTION (provided by applicant): Flavopiridol, a small molecule CDK inhibitor undergoing antineoplastic clinical trials, induces apoptosis in human cancer cell lines, is synergistic with a variety of other antineoplastic agents and has induced xenograft tumor regressions as well as responses in flavopiridol-treated patients. Although CDK inhibition is clearly a factor in flavopiridol-induced cytostasis, the mechanism(s) responsible for flavopiridol-induced cytotoxicity are uncertain. Because 1) NCI COMPARE analysis implicates DNA as an important cytotoxic target of flavopiridol and 2) flavopiridol does not inhibit topoisomerases, inflict DNA damage or covalently modify DNA, we hypothesized that flavopiridol-induced cytotoxicity may be attributable to its ability to disrupt protein/DNA interactions, in evaluating this hypothesis, we have found that flavopiridol 1) binds to double-stranded DNA with similar affinity constant to other DNA-interacting antineoplastic agents, 2) disrupts STAT-3/DNA interactions in vitro in three model systems, 3) downregulates antiapoptotic proteins downstream of STAT-3 including Mcl-1 in vitro at the transcriptional level and 4) downregulates the antiapoptotic protein Mcl-1 in malignant LGLs (large granular lymphocytes) ex vivo and in leukemic cells isolated from flavopiridol-treated patients with AML. We now propose to more fully examine the hypothesis that flavopiridol-induced cytotoxicity may result from its ability to disrupt survival-critical transcription factor/DNA interactions according to the following Specific Aims: 1. Further definition of the specificity of flavopiridol-induced disruption of transcription factor/DNA interactions. 2. Further characterization of the ability of flavopiridol to disrupt STAT-3/DNA binding and definition of its molecular basis. 3. Evaluation of the contributions of flavopiridol-induced disruption of STAT-mediated transcription to flavopiridol-induced cytotoxicity. 4. Preliminary examination of whether flavopiridol may represent a potential therapy in the treatment of patients afflicted with LGL malignancies. Through the proposed studies, we hope not only to gain insights that will help to clarify the mechanism(s) responsible for flavopiridol-induced cytotoxicity, but also to contribute to the understanding of transcription factor/DNA complexes as promising novel antineoplastic targets.

描述（由申请人提供）：Flavopiridol是一种小分子CDK抑制剂，正在进行临床试验，可诱导人癌细胞系的细胞凋亡，与多种其他抗肿瘤药物具有协同作用，并诱导异种移植肿瘤消退以及Flavopiridol治疗患者的反应。虽然CDK抑制明显是flavopiridol诱导的细胞抑制的一个因素，但flavopiridol诱导的细胞毒性的机制尚不确定。由于1）NCI COMPARE分析表明DNA是flavopiridol的重要细胞毒性靶点，2）flavopiridol不会抑制拓扑异构酶，造成DNA损伤或共价修饰DNA，因此我们假设flavopiridol诱导的细胞毒性可能归因于其破坏蛋白质/DNA相互作用的能力，在评估这一假设时，我们已经发现，1）Flavopiridol以与其它DNA相互作用抑制剂相似的亲和常数结合双链DNA，2）在三种模型系统中破坏体外STAT-3/DNA相互作用，3）在体外在转录水平下调STAT-3下游的抗凋亡蛋白，包括Mcl-1，和4）在离体恶性LGL（大颗粒淋巴细胞）中和在分离自经flavopiridol治疗的AML患者的白血病细胞中下调抗凋亡蛋白Mcl-1。我们现在建议更全面地检查这一假设，即flavopiridol诱导的细胞毒性可能是由于其破坏生存关键转录因子/DNA相互作用的能力，根据以下具体目的：1。进一步定义flavopiridol诱导的转录因子/DNA相互作用破坏的特异性。2.进一步表征flavopiridol破坏STAT-3/DNA结合的能力及其分子基础的定义。3. Flavopiridol诱导的STAT介导的转录的破坏对Flavopiridol诱导的细胞毒性的贡献的评估。4.初步检查flavopiridol是否可能代表一种潜在的治疗患有LGL恶性肿瘤的患者。通过拟议的研究，我们希望不仅获得有助于阐明flavopiridol诱导细胞毒性的机制的见解，而且有助于理解转录因子/DNA复合物作为有前途的新靶点。