Epigenetic Synergy Between DNMT and EZH1/2 Inhibitors for Therapy in Solid Tumors

项目摘要 DNA甲基转移酶抑制剂（DNMTi），如FDA批准的核苷类似物5-氮杂-2 '-脱氧胞苷 (DAC)，是目前唯一可用的临床药物，可以逆转癌细胞中异常的DNA甲基化 并且已经成为增加癌症免疫疗法功效的潜在手段。然而，DNA 这些试剂的去甲基化效用，特别是在实体瘤中，没有达到期望的下游甲基化。 在临床前模型中观察到的转录结果。因此，调节DNMT的新治疗策略 活动是迫切需要的，并直接在这个SPORE项目中解决。我们的初步数据显示， 几种临床应用的EZH 1/2抑制剂阻断PRC 2在选择肿瘤中的补偿性抑制活性 抑制基因和重复元件，随后通过DAC去除DNA甲基化。阻断这种 抑制性“表观遗传开关”，我们认为这是在患者中观察到的DNMTi耐药的关键因素 用这些药物治疗，可能是观察到的DNMTi+ EZH 1/2 i协同作用的基础， 基因和基因间转录沉默。我们的总体目标是确定转录协同机制 和DNMTi+ EZH 1/2 i引起的免疫串扰，并评估这种表观遗传的临床潜力。 治疗组合，单独使用，以及作为免疫疗法的引物。为此，我们将（目标1）定义癌症 细胞内染色质调节机制和参与分子和治疗的细胞途径 EZH 1/2和DNMT联合抑制的效果。同时，我们将（目的2）在小鼠模型中确定 检查点疗法抗性疾病，EZH 1/2和DNMT联合抑制对癌症的抗肿瘤作用 vs.免疫细胞和那些依赖于两者之间的相互作用。此外，拟议的1期临床 一项试验，包括广泛的相关科学终点，将（目标3）验证EZH 1/2组合的影响 和DNMT抑制剂治疗对免疫应答基因信号通路和肿瘤微环境的影响 多种实体瘤类型。本研究的影响包括：1）确定了分子生物学的可利用机制， 与DNMTi治疗相关的串扰; 2）使DNMTi+ EZH 1/2 i治疗的有效临床应用成为可能; 3)揭示相关的生物标志物以评估药物在患者肿瘤中的作用;以及4）扩大以下的机会： 检查点和靶向免疫治疗组合。

PROJECT SUMMARY DNA methyltransferase inhibitors (DNMTi), such as the FDA-approved nucleoside analog 5-aza-2'-deoxycytidine (DAC), are currently the only available clinical drugs that can reverse abnormal DNA methylation in cancer cells and have emerged as a potential means to increase the efficacy of immunotherapy in cancer. However, the DNA de-methylation utility of these agents, particularly in solid tumors, does not attain the desired downstream transcriptional consequences seen in preclinical models. As such, novel therapeutic strategies to regulate DNMT activity are urgently needed and are directly addressed in this SPORE project. Our preliminary data shows that several clinically applied EZH1/2 inhibitors block compensatory repressive activity of PRC2 at select tumor suppressor genes and repeat elements consequent to DNA methylation removal by DAC. Blocking this repressive “epigenetic switch,” which we propose is a key contributor to DNMTi resistance seen in patients treated with these drugs, may underlie an observed synergy of DNMTi+EZH1/2i to de-repress cancer-associated genic and intergenic transcriptional silencing. Our overall goal is to define mechanisms of transcriptional synergy and immune crosstalk consequent to DNMTi+EZH1/2i and evaluate the clinical potential of this epigenetic therapeutic combination, alone, and as a primer to immunotherapy. To this end, we will (Aim 1) define cancer cell-intrinsic chromatin regulatory mechanisms and cellular pathways involved in the molecular and therapeutic effects of combined EZH1/2 and DNMT inhibition. Concurrently, we will (Aim 2) determine in mouse models of checkpoint therapy resistant disease, the antitumor effects of combined EZH1/2 and DNMT inhibition on cancer vs. immune cells and those dependent on interactions between the two. In addition, a proposed Phase 1 clinical trial, inclusive of extensive correlative science endpoints, will (Aim 3) validate the impact of combination EZH1/2 and DNMT inhibitor therapy on immune-response gene signaling circuits and the tumor microenvironment across multiple solid tumor types. Impacts of our studies include: 1) defining exploitable mechanisms of molecular crosstalk associated with DNMTi therapy; 2) enabling effective clinical application of DNMTi+EZH1/2i therapy; 3) revealing correlative biomarkers to assess drug action in patient tumors; and 4) expanding opportunities for checkpoint and targeted immunotherapy combinations.