Targeting KDM4B, a novel alternative splicing regulator, in castration-resistant prostate cancer (CRPC)

靶向 KDM4B（一种新型选择性剪接调节因子）治疗去势抵抗性前列腺癌 (CRPC)

基本信息

批准号：
10116972
负责人：
Jer-Tsong Hsieh
金额：
$ 41.38万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-01-01 至 2022-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10116972
关键词：
3&apos Splice Site Address Alternative Splicing Androgen Antagonists Androgen Receptor Animal Model Antineoplastic Agents Binding Biological Assay Biological Availability Cancer Patient Characteristics Chemicals Chromatin Chromatin Structure Clinical Data Development Drug Kinetics Drug resistance Enzymes Epigenetic Process Exons FDA approved Generations Genes Genomic approach Goals Growth Hormones Human In Vitro Lead Ligand Binding Domain Link Malignant Neoplasms Malignant neoplasm of prostate Metabolic Metastatic Prostate Cancer Molecular Neoplasm Circulating Cells Oncogenic Pattern Pharmaceutical Chemistry Physiological Play Process Prognosis Property Protein Isoforms Proteins RNA Binding RNA Splicing Refractory Regulatory Element Resistance Role Spliceosomes Testing Therapeutic Trans-Activators Transgenic Mice Treatment Efficacy Variant androgen deprivation therapy base cancer cell cancer therapy castration resistant prostate cancer chromatin immunoprecipitation clinical candidate clinically relevant comparative design drug candidate effective therapy genome-wide high risk histone demethylase in vivo inhibitor/antagonist mRNA Precursor men next generation novel novel therapeutics overexpression pre-clinical prostate cancer cell prostate cancer cell line prostate cancer progression recruit standard care success targeted treatment therapy resistant tumorigenesis

项目摘要

Alternative splicing of pre-mRNA is a fundamental mechanism to generate protein diversity that is often deregulated in cancer cells, producing aberrant proteins that promote growth and survival. Growth of prostate cancer (PCa) is driven by the androgen receptor (AR) activities. The standard care for metastatic PCa is androgen-deprivation therapy (ADT). However, ADT inevitably leads to castration-resistant PCa (CRPC) that, while still relies on the AR activities, is no longer hormone-sensitive. Among the many mechanisms underlying CRPC, is the generation of constitutively active AR variants (AR-Vs) through alternative splicing. Of note is AR- V7, which may play a causal role in PCa progression and treatment resistance. Until now, no FDA-approved agent can target these AR-Vs. Recently, we identified a pro-oncogenic role for histone demethylase KDM4B in PCa and several chemical inhibitors of KDM4B. In our preliminary studies, we found that KDM4B is necessary and sufficient to promote AR-V7 expression. KDM4B binds RNA and interacts with many trans-acting factors and may regulate alternative splicing of AR at both the pre-mRNA and chromatin levels. In addition, KDM4B may have other genome-wide alternatively spliced targets that are hallmarks of cancer. High KDM4B expression in human PCa patients predicts poor prognosis and correlates with elevated AR-V7 expression. Based on these scientific premises, we hypothesize that KDM4B may be a gene-specific alternative splicing regulator that dictates an oncogenic splicing pattern in CRPC and that targeting this enzyme could inhibit CRPC and re-sensitize CRPC to current ADT. We propose three specific aims to test this hypothesis. Aim 1: To determine the molecular mechanisms by which KDM4B regulates alternative splicing of AR-Vs. KDM4B may promote alternative splicing by recruiting the spliceosome to the 3'-splice site of alternative exons via binding to splicing regulatory elements (SREs) and by changing the chromatin structures around alternatively spliced exons. We will identify these SREs and determine the chromatin landscape around alternatively spliced exons. Aim 2. To identify KDM4B-regulated genome-wide splice variants. Preliminary studies indicated that KDM4B may have additional alternatively spliced variants that are specific for PCa tumorigenesis. We will test this hypothesis by comparative profiling genome-wide KDM4B-targeted splice variants, their associated SREs and chromatin landscapes in both hormone-sensitive and refractory PCa cells. Aim 3. To generate a clinical candidate(s) through optimization of KDM4B inhibitors. Our data indicated that the KDM4B inhibitor B3 may serve as a strong lead compound for further optimization to generate a clinical candidate agent. We will optimize B3 through iterative rounds of medicinal chemistry design, synthesis and testing. The notion that KDM4B is an oncogenic regulator of alternative splicing is novel. Understanding mechanism of action of KDM4B and identifying potent KDM4B inhibitors with in vivo efficacy will have significant clinical impact on the development of new therapies for CRPC with active oncogenic alternatively spliced variants.

前体 mRNA 的选择性剪接是产生蛋白质多样性的基本机制，通常是癌细胞失调，产生促进生长和存活的异常蛋白质。前列腺生长癌症（PCa）是由雄激素受体（AR）活动驱动的。转移性 PCa 的标准护理是雄激素剥夺疗法（ADT）。然而，ADT 不可避免地会导致去势抵抗性前列腺癌 (CRPC)，同时仍依赖AR活动，不再对激素敏感。在众多潜在机制中 CRPC 是通过选择性剪接生成组成型活性 AR 变体 (AR-V)。值得注意的是 AR- V7，可能在 PCa 进展和治疗抵抗中发挥因果作用。到目前为止，还没有FDA批准的代理可以针对这些 AR-V。最近，我们发现组蛋白去甲基化酶 KDM4B 在 PCa 和 KDM4B 的几种化学抑制剂。在我们的初步研究中，我们发现KDM4B是必要的并足以促进AR-V7表达。 KDM4B 结合 RNA 并与许多反式作用因子相互作用并可能在前 mRNA 和染色质水平上调节 AR 的选择性剪接。此外，KDM4B 可能还有其他全基因组选择性剪接靶标，这些靶标是癌症的标志。高KDM4B 人类 PCa 患者中的表达可预测不良预后，并与 AR-V7 表达升高相关。基于这些科学前提，我们假设 KDM4B 可能是基因特异性的选择性剪接决定 CRPC 中致癌剪接模式的调节因子，并且针对该酶可以抑制 CRPC 并使 CRPC 对当前 ADT 重新敏感。我们提出了三个具体目标来检验这一假设。目标 1：确定 KDM4B 调节 AR-V 选择性剪接的分子机制。 KDM4B 可以通过将剪接体募集到替代外显子的 3'-剪接位点来促进替代剪接与剪接调节元件 (SRE) 结合并通过交替改变染色质结构剪接的外显子。我们将识别这些 SRE 并确定选择性剪接周围的染色质景观外显子。目标 2. 鉴定 KDM4B 调节的全基因组剪接变体。初步研究表明 KDM4B 可能具有额外的选择性剪接变体，这些变体对 PCa 肿瘤发生具有特异性。我们将测试这一假设是通过比较分析全基因组 KDM4B 靶向剪接变体及其相关的 SRE 以及激素敏感型和难治性 PCa 细胞中的染色质景观。目标 3. 生成临床通过优化 KDM4B 抑制剂的候选者。我们的数据表明 KDM4B 抑制剂 B3 可能作为强大的先导化合物，用于进一步优化以产生临床候选药物。我们将通过迭代的药物化学设计、合成和测试来优化 B3。的想法是 KDM4B 是一种新颖的选择性剪接致癌调节因子。了解作用机制 KDM4B 和鉴定具有体内功效的强效 KDM4B 抑制剂将对以下领域产生重大临床影响：开发具有活性致癌选择性剪接变体的 CRPC 新疗法。