Cyclin Dependent Kinases as Epigenetic Therapy Targets

项目总结 表观遗传疗法旨在对癌细胞中的基因表达进行重新编程，以达到治疗效果。到目前为止， DNA甲基转移酶(DNMT)抑制(DNMTi)是最有效的表观遗传治疗形式， 在髓系白血病中尤为活跃。使用活细胞分析来筛选达到相同程度的药物 作为DNMTi的表观遗传重编程，我们发现了一类新的表观遗传药物，可以激活沉默的 通过抑制CDK9的表达。细胞周期蛋白依赖性蛋白激酶(CDK)在临床上具有重要的意义 肿瘤的治疗分为两类--细胞周期调节(如CDK1、2、4、6等)。和转录的 监管者(如7、9、12等)。我们的新数据将CDK9置于调控这两个基因的节点的中心 沉默和激活。靶向CDK9对基因表达具有多效性作用，这似乎是理想的 抗肿瘤观点：人们观察到(肿瘤抑制基因)同时激活、抑制( 癌基因)，以及干扰素免疫信号的诱导，这可能是癌症的免疫增敏 心理治疗。考虑到最近基于免疫的惊人发展，后一种效应特别有趣 治疗，我们的初步数据表明，CDK9靶向可能是一种有用的新方法 免疫增敏。有趣的是，CDK9可能不是唯一参与免疫调节的CDK。抑制 CDK4/6和CDK5已被证明在癌症中诱导干扰素反应和/或免疫增敏 心理治疗。此外，其他转录的CDKs(如CDK7)与CDK9有共同的磷酸化靶点，提高了 它们也同样影响基因沉默的可能性。鉴于针对CDK4和/或6的药物正在临床上 用于乳腺癌，靶向CDK7和/或9的药物正在进行临床试验，因此了解 其他CDK是否也是免疫增敏的表观遗传调节因子。表观遗传效应可能导致不同的 这些药物的临床开发策略(例如，低剂量而不是MTD，预期反应缓慢 需要多个周期才能发生，等等。)以及组合策略的设计(组合表观遗传学 治疗、联合使用免疫检查点抑制剂等)。因此，本项目旨在检验这一假说 靶向CDK导致免疫增敏表观遗传效应。我们将证实这一假设并进行检验 癌症治疗的机制和临床/翻译的三个目标：(I)免疫增敏 抑制CDK9，我们将研究增强其作用的机制和潜在途径；(Ii)表观遗传学 CDK的作用，我们将询问靶向CDK4、5、6和7是否具有类似的表观遗传学和 针对CDK9的免疫增敏作用；和(Iii)联合CDK9的临床前研究和临床试验 AML和MDS的抑制、DNMT抑制和免疫检查点抑制，我们将在其中完成 联合DNMT将CDK靶向作为表观遗传疗法引入临床的必要性研究 靶向和免疫检查点抑制。这些目标的成功实现将带来一种新的形式 癌症和白血病的表观遗传疗法。

PROJECT SUMMARY Epigenetic therapy aims to reprogram gene expression in cancer cells to achieve a therapeutic effect. To date, DNA methyltransferase (DNMT) inhibition (DNMTi) is the most effective form of epigenetic therapy, being particularly active in myeloid leukemias. Using a live cell assay to screen for drugs that achieve the same degree of epigenetic reprogramming as DNMTi, we discovered a new class of epigenetic drugs that activate silenced expression through inhibition of CDK9. Cyclin Dependent Kinases (CDKs) are of considerable clinical interest in cancer therapy and fall into two classes – cell cycle regulatory (e.g. CDK1,2,4,6 etc.) and transcriptional regulators (e.g. CDK7,9,12 etc.). Our new data place CDK9 at the heart of a node that regulates both gene silencing and activation. Targeting CDK9 has pleotropic effects on gene expression that appear ideal from an anti-tumor perspective: One observes simultaneous gene activation (of tumor suppressors), repression (of oncogenes), and induction of an interferon immune signature, which may be immunosensitizing for cancer therapy. This latter effect is of particular interest given the phenomenal recent development of immune based therapies, and our preliminary data suggest that CDK9 targeting may be a useful new approach to immunosensitization. Interestingly, CDK9 may not be the only CDK involved in immune regulation. Inhibition of CDK4/6 and of CDK5 have been shown to induce an IFN response and/or to be immunosensitizing in cancer therapy. Moreover, other transcriptional CDKs (e.g. CDK7) share phosphorylation targets with CDK9, raising the possibility that they also similarly affect gene silencing. Given that drugs that target CDK4 and/or 6 are in clinical use in breast cancer, and drugs targeting CDK7 and/or 9 are in clinical trials, it becomes important to know whether other CDKs are also immunosensitizing epigenetic regulators. Epigenetic effects may lead to different strategies for clinical development of these drugs (e.g. low doses rather than MTD, expectation of slow responses that take multiple cycles to occur, etc.) and for the design of combination strategies (combined epigenetic therapy, combinations with immune checkpoint inhibitors etc.). This project therefore aims to test the hypothesis that targeting CDKs leads to immunosensitizing epigenetic effects. We will confirm this hypothesis and test mechanisms and clinical/translational implications for cancer therapy in three aims: (i) Immunosensitization by CDK9 inhibition, in which we will study mechanisms and potential ways to enhance the effects; (ii) Epigenetic effects of CDKs, in which we will ask whether targeting CDK4,5,6 and 7 has similar epigenetic and immunosensitizing effects as targeting CDK9; and (iii) Preclinical studies and a clinical trial of combined CDK9 inhibition, DNMT inhibition and Immune checkpoint inhibition in AML and MDS, in which we will complete the necessary studies to bring CDK targeting as epigenetic therapy into the clinic, in combination with DNMT targeting and immune checkpoint inhibition. Successful achievement of these aims will introduce a new form of epigenetic therapy for cancer and leukemias.