Defining and targeting the epigenetic programs involved in melanoma development

项目总结 紫外线照射(UVR)长期以来一直与黑色素瘤的发生有关，有明显的相关性 在纬度和黑色素瘤发病率之间，特别是在皮肤白皙和能力较差的人中 把皮肤晒黑。因此，散发性皮肤黑色素瘤是所有癌症中突变负担最高的癌症之一。这个 紫外线照射后的高突变负荷与新抗原负荷增加和更大的 免疫识别。这些观察表明，引发黑色素瘤的黑素细胞在紫外线照射下存活- 诱导应激/细胞损伤，从而避免免疫识别。我们实验室的无关研究集中在BRAF上 黑色素瘤中的抑制剂耐药性确定了一种通过组蛋白介导的应激激活表观遗传程序 脱乙酰酶(HDAC)-8，通过 转录重编程。这项建议的目标是开发新的黑色素瘤预防方法 针对紫外线损伤的黑素细胞所需的表观遗传程序的策略，以避免细胞死亡和 免疫识别。我们将测试UVR诱导的HDAC8激活允许黑素细胞 避免细胞死亡和免疫攻击，允许具有致病突变的细胞存活并随后发育成 黑色素瘤。这一建议在寻求定义HDAC8在表观遗传学中的作用方面具有概念上的创新 经历紫外线诱导的压力和DNA损伤的黑素细胞的重新编程。我们将进一步解决 免疫逃避在黑色素瘤前驱病变发展中的作用及将独特的小鼠 模型、单细胞RNA-Seq和多OMICS方法，以确定参与 构成黑色素瘤前驱病变的紫外线损伤的黑素细胞的持久性 发展。在目标1中，我们将定义HDAC8如何调节黑素细胞的转录图谱 并将确定这如何有助于提高细胞存活率和减少 免疫原性。然后，我们将使用我们最近开发的HDAC8小鼠模型来演示 HDAC8-诱导黑色素瘤发展，并将执行单细胞RNA-Seq和免疫图谱以 描述黑素细胞中HDAC8的激活如何调节皮肤的免疫微环境。在……里面 目的2，我们将确定是否使用遗传沉默或小分子HDAC8来抑制HDAC8 抑制剂逆转黑素细胞中激活的存活和免疫逃逸转录程序 在紫外线照射后。体内研究将评估HDAC8抑制剂或沉默HDAC8在 小鼠皮肤黑素细胞足以延缓我们BRAF黑色素瘤的开始发展 突变/PTEN沉默的黑色素瘤模型，以及免疫系统在此反应中的作用。在完成时 我们希望这项工作证明了HDAC8抑制剂作为一种 新的黑色素瘤预防策略。

Project summary Ultraviolet radiation (UVR) exposure has long been linked to melanoma development, with clear correlations seen between latitude and the incidence of melanoma, particularly in individuals with fair skin and a poor ability to tan. As such, sporadic cutaneous melanoma has one of the highest mutational burdens of all cancers. The high mutational burden following UVR exposure is associated with increased neoantigen load and greater immune recognition. These observations suggest that the melanocytes that initiate melanoma survive UVR - induced stress/cell damage and then avoid immune recognition. Unrelated studies in our lab focused on BRAF inhibitor resistance in melanoma identified a stress-activated epigenetic program mediated through histone deacetylase (HDAC)-8 that allowed escape from both cell death and immune recognition through transcriptional reprogramming. The objective of this proposal is to develop novel melanoma prevention strategies that target the epigenetic programs required for UVR-damaged melanocytes to avoid cell death and immune recognition. We will test the hypothesis that UVR-induced HDAC8 activation allows melanocytes to avoid cell death and immune attack, allowing cells with pathogenic mutations to survive and later develop into melanoma. This proposal is conceptually innovative in seeking to define the role of HDAC8 in the epigenetic reprogramming of melanocytes that experience UVR-induced stress and DNA damage. We will further address the role of immune evasion in the development of melanoma precursor lesions and will use unique mouse models, single cell RNA-Seq, and multi-Omics approaches to identify core pathways and regulators involved in the persistence of UVR-damaged melanocytes that constitute the precursor lesions for melanoma development. In Aim 1, we will define how HDAC8 modulates the transcriptional profile of melanocytes following UV-irradiation and will determine how this contributes to increased cell survival and reduced immunogenicity. We will then use our recently developed HDAC8 mouse model to demonstrate the role for HDAC8-induction in melanoma development and will perform single cell RNA-Seq and immune profiling to characterize how HDAC8 activation in melanocytes modulates the immune microenvironment of the skin. In Aim 2, we will determine whether inhibition of HDAC8 using genetic silencing or small molecule HDAC8 inhibitors reverses the survival and immune escape transcriptional programs that are activated in melanocytes following UVR exposure. In vivo studies will evaluate whether HDAC8 inhibitors or silencing of HDAC8 in mouse skin melanocytes are sufficient to delay the initiation of melanoma development in our BRAF mutant/PTEN-silenced melanoma model, and the role of the immune system in this response. At completion of this work we expect to have demonstrated the proof-of-principle for the development of HDAC8 inhibitors as a novel melanoma prevention strategy.