Loss of Filamin A Nuclear Localization in Prostate Cancer Progression

丝蛋白的丢失是前列腺癌进展中的核定位

• 批准号: 9103860
• 负责人: PARAMITA M. GHOSH
• 金额: --
• 依托单位: VA NORTHERN CALIFORNIA HEALTH CARE SYS
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9103860
• 关键词: Acetates; Actin-Binding Protein; Address; Adverse effects; Affect; Androgen Antagonists; Androgen Receptor; Androgen Response Element; Androgens; Animal Model; Apoptosis; Bicalutamide; Binding; Blood; California; Calpain; Cancer Patient; Castration; Cell Line; Cell Nucleus; Cell Survival; Cells; Cleaved cell; Cytoplasm; Data; Drug resistance; Drug usage; Ensure; Epithelial Cells; Epithelium; Equilibrium; Funding; GDF15 gene; Gene Targeting; Generations; Genes; Genetic Transcription; Goals; Health; Healthcare Systems; Hormones; Human; Immunocompromised Host; Implant; Induction of Apoptosis; Ligands; Malignant neoplasm of prostate; Mediating; Molecular Profiling; Mus; Neoplasm Metastasis; Nuclear; Oncologist; Patients; Peptide Hydrolases; Pharmaceutical Preparations; Phosphorylation; Physicians; Plasma; Prednisone; Prostate; Proteolysis; Publishing; Quality of life; RNA; RNA Sequences; Receptor Inhibition; Recurrence; Relapse; Reporting; Research; Resistance; Resistance development; Role; Scaffolding Protein; Serum; Small RNA; Specificity; TMPRSS2 gene; Testing; Tissues; Travel; VEGFA gene; Veterans; abiraterone; addiction; base; biomarker panel; castration resistant prostate cancer; chemotherapy; clinical decision-making; deprivation; filamin; genome-wide; individual patient; inhibitor/antagonist; jun Oncogene; molecular marker; mouse model; mutant; next generation sequencing; novel; predicting response; predictive marker; prevent; promoter; prostate cancer cell; public health relevance; response; response biomarker; standard of care; tool; transcription factor; transcriptome sequencing; tumor; tumor progression; tumor xenograft

 DESCRIPTION (provided by applicant): This renewal application addresses the role of the scaffolding protein Filamin A (FlnA) in the progression of prostate cancer (CaP), and tests the hypothesis that loss of FlnA nuclear localization in the luminal epithelial cells of CaP signifies resistance of the tumor to anti-androgens bicalutamide, abiraterone acetate or enzalutamide, that are used to treat patients with castration resistant prostate cancer (CRPC). This hypothesis is based on preliminary and published data demonstrating that in the presence of nuclear FlnA, CaP cells and animal models respond to anti-androgens whereas in the absence of nuclear FlnA, they do not respond. Based on available preliminary data, we propose that in the presence of nuclear FlnA, some AR transcriptional targets, such as TMPRSS2, VEGFA, GDF15, IL32, and JUN (which were identified in a RNA-Seq analysis as FlnA-regulated AR transcriptional targets), are selectively targeted for transcription only upon androgen stimulation. Since these genes regulate cell survival, this will cause androgen-addiction, whereby the cells become susceptible to apoptosis induction by anti-androgens. In Aim 1, we will identify targets of AR affected by FlnA nuclear localization. Since many of these are also targets of the transcriptional factor Sp1, we hypothesize that FlnA regulates the selectivity of AR targets by bringing AR together with selected transcriptional factors such as Sp1. Further, we hypothesize that FlnA regulates this selectivity and overall transcriptional activity by binding to the AR hinge region and thereby controlling the binding partners of AR. Therefore, nuclear FlnA can regulate androgen sensitivity by preventing binding to co-activators that encourage ligand-independent transcriptional activity. The significance of these studies is that they will determine whether in CRPC cells, AR loses its target specificity and that FlnA localization to the nucleus is able to restore that specificity. In Aim 2, we will investigate why FlnA is lost from the epithelia in some CRPC tumors and not in others. FlnA nuclear localization involves the cleavage of this molecule by calpains whereby one of the cleaved products translocates to the nucleus; however, phosphorylation of FlnA at S2152 impedes cleavage by these proteases, thereby preventing nuclear localization. Therefore, we will determine whether expression of FlnA in the nucleus or the lack thereof, results from a loss of equilibrium between calpain activity and FlnA phosphorylation. The hypothesis will be further tested using patient derived xenograft (PDX) tumor lines orthotopically implanted in the prostates of immunocompromised NOD-SCID IL-2Rγ-null (NSG) mouse, and will determine whether response to these drugs correlate with the expression of FlnA in the nuclei. Finally, in Aim 3, we will determine whether targets of FlnA-regulated AR transcriptional activity may be used to determine whether human patients with CRPC will respond to abiraterone or enzalutamide. This will be necessary because no tissue other than blood is usually available from CRPC patients for analysis, therefore, we will determine whether such markers exist in the serum or plasma, and whether these markers correlate with FlnA nuclear localization. Blood from 50 VA patients with CRPC, who will be treated with bicalutamide, abiraterone acetate+prednisone or with enzalutamide, as standard-of-care, will be used for these studies. The level of selected markers in the blood will be correlated with the response of these patients to the drugs. The significance of the proposed studies is that they will provide VA physicians with a tool to determine whether a patient will respond to the standard of care use of bicalutamide, abiraterone or enzalutamide. In addition, the proposed studies will determine the role of FlnA nuclear localization on AR transcriptional activity and confer a novel role for a co-regulator. Further, the genome wide analyses studies proposed will enable the identification of novel AR transcriptional targets.

 描述（由申请人提供）： 这项更新申请阐述了支架蛋白细丝蛋白 A (FlnA) 在前列腺癌 (CaP) 进展中的作用，并测试了以下假设：CaP 管腔上皮细胞中 FlnA 核定位的丧失意味着肿瘤对抗雄激素比卡鲁胺、醋酸阿比特龙或恩杂鲁胺，用于治疗去势抵抗性前列腺癌 (CRPC) 患者。该假设基于初步和已发表的数据。证明在核 FlnA 存在的情况下，CaP 细胞和动物模型对抗雄激素有反应，而在核 FlnA 不存在的情况下，它们没有反应。根据现有的初步数据，我们建议在核 FlnA 存在的情况下，一些 AR 会产生反应。转录靶标，例如 TMPRSS2、VEGFA、GDF15、IL32 和 JUN（在 RNA-Seq 分析中被鉴定为 FlnA 调节的 AR 转录靶标），仅在雄激素刺激。由于这些基因调节细胞存活，这会导致雄激素成瘾，因此细胞容易受到抗雄激素诱导的凋亡。 在目标 1 中，我们将确定受 FlnA 核定位影响的 AR 靶点，因为其中许多也是转录因子 Sp1 的靶点，我们发现 FlnA 通过将 AR 与选定的转录因子（例如 Sp1）结合在一起来调节 AR 靶点的选择性。此外，我们发现 FlnA 通过与 AR 铰链区结合来调节这种选择性和整体转录活性，从而控制 AR 的结合伴侣。因此，核 FlnA 可以通过阻止与 AR 结合来调节雄激素敏感性。这些研究的意义在于，它们将确定在 CRPC 细胞中，AR 是否会失去其靶标特异性，并且 FlnA 定位到细胞核是否能够恢复该特异性。 在目标 2 中，我们将研究为什么 FlnA 在某些 CRPC 肿瘤中从上皮细胞中丢失，而在其他肿瘤中则不然。 S2152 阻碍这些蛋白酶的切割，从而阻止核定位，因此，我们将确定 FlnA 是否在细胞核中表达。其缺乏是由于钙蛋白酶活性和 FlnA 磷酸化之间失去平衡所致。该假设将使用原位植入免疫功能低下的 NOD-SCID IL-2Rγ-null (NSG) 前列腺中的患者来源的异种移植 (PDX) 肿瘤系进行进一步测试。小鼠，并将确定对这些药物的反应是否与细胞核中 FlnA 的表达相关。 最后，在目标 3 中，我们将确定 FlnA 调节的 AR 转录活性靶标是否可用于确定患有 CRPC 的人类患者是否会对阿比特龙或恩杂鲁胺产生反应，因为除了血液之外通常无法从 CRPC 中获得其他组织。因此，我们将确定这些标记物是否存在于血清或血浆中，以及这些标记物是否与 50 名患有 CRPC 的 VA 患者的血液中的 FlnA 核定位相关。比卡鲁胺、醋酸阿比特龙+泼尼松或恩杂鲁胺作为标准治疗将用于这些研究。血液中选定标记物的水平将与这些患者对药物的反应相关。研究的重点是，他们将为 VA 医生提供一个工具来确定患者是否会对比卡鲁胺、阿比特龙或恩杂鲁胺的护理使用标准做出反应。此外，拟议的研究将确定患者是否会对比卡鲁胺、阿比特龙或恩杂鲁胺的护理使用标准做出反应。 FlnA 核定位对 AR 转录活性的作用，并赋予协同调节剂新的作用。此外，提出的全基因组分析研究将能够识别新的 AR 转录靶标。