Deciphering the interplay between H3K36 and DNA methylation in renal cancer

透明细胞肾癌(CcRCC)是美国第八大癌症死亡原因。而当 大多数局限性肾癌通过手术治愈，约30%的患者进展到远处转移 存活率降至两年，且尚无根治疗法。在过去的五年里，令人振奋的新 研究结果显示，调控表观基因组的基因，包括SETD2，BAP1和PBRM1，在 &gt；50%的肾细胞癌病例。这类突变启动和推动肿瘤发生的机制， 然而，仍然完全不清楚。表观基因组在癌症中被严重破坏。最好的之一 特征性的表观遗传标记是DNA甲基化(5mC)。5mC是一种有效的转录抑制信号 存在于启动子和增强子中，但矛盾的是与基因中的转录呈正相关 身体。在癌症进展过程中，生长调节基因的启动子和增强子是靶向 高甲基化介导的沉默，而基因组的其他区域失去5mC，如基因体。5mC DNA甲基转移酶和组蛋白H3赖氨酸36三甲基化(H3K36me3) SETD2共定位于基因体中，其水平随着转录水平的升高而升高，Dnmt3b与H3K36me3结合 提供了一种机械连接。我们的初步和公布的数据显示，在5mC和5mC之间存在新的串扰 H3K36me3在ccRCC中，其中SETD2失活导致5mC靶向基因体和 戏剧性的全基因组DNA超甲基化，表明SETD2突变代表着一种新的 类似IDH1/IDH2突变的高甲基化子驱动基因。我们的长期目标是将SETD2作为一种 理解表观遗传调节基因突变如何驱动肿瘤发生以及这些 突变是可以针对的。我们对这一应用的特定假设是SETD2突变驱动ccRCC 部分是通过导致全球DNA超甲基化，促进更具侵袭性、转移性的基因表达 程序。此外，我们假设这类ccRCC对DNA低甲基化药物敏感。 我们将通过三个目标来解决这一假设。在目标1中，我们将描述 5mC/Dnmts和H3K36me3，以确定SETD2突变导致5mC异常的机制 靶向和基因表达。在目标2中，我们询问了SETD2突变如何介导5mC的去调节 转录模式影响细胞的生长、转移和对表观组靶向药物的敏感性。 最后，在目标3中，我们定义了与EMT相关联的5MC签名，并验证和表征了关键的5MC放松管制 通过H3K36me3活性丧失驱动转移基因表达程序的事件。我们的研究将 揭示了基因组和表观基因组是如何相互作用的，并提供了一幅详细的图像，说明了 表观遗传调控基因驱动肿瘤发生。预计这将对人类健康产生积极影响， 为了更完整地了解癌症的分子病因学和表观遗传调控 突变和推动新疗法的发现，这些疗法专门针对他们放松调控的途径。

Clear cell renal carcinoma (ccRCC) is the 8th leading cause of cancer death in the United States. While the majority of localized RCC is cured with surgery, ~30% of patients progress to distant metastases where survival drops to <2 years and for which no curative therapies exist. Over the past five years exciting new findings revealed that genes regulating the epigenome, including SETD2, BAP1, and PBRM1, are mutated in >50% of ccRCC cases. The mechanism by which this class of mutations initiates and drives tumorigenesis, however, remains completely unknown. The epigenome is profoundly disrupted in cancer. One of the best characterized epigenetic marks is DNA methylation (5mC). 5mC is a potent transcriptional repressive signal when present in promoters and enhancers, but paradoxically is associated positively with transcription in gene bodies. During cancer progression, promoters and enhancers of growth regulatory genes are targeted for hypermethylation-mediated silencing while other regions of the genome lose 5mC, such as gene bodies. 5mC mediated by DNA methyltransferases and histone H3 lysine 36 trimethylation (H3K36me3) mediated by SETD2 co-localize in gene bodies, their levels increase with transcription, and DNMT3B binds to H3K36me3 providing a mechanistic link. Our preliminary and published data reveal a novel crosstalk between 5mC and H3K36me3 in ccRCC, in which SETD2 inactivation results in loss of 5mC targeting to gene bodies and dramatic genome-wide DNA hypermethylation, demonstrating that SETD2 mutation represents a new hypermethylator driver gene akin to IDH1/IDH2 mutation. Our long term goal is to use SETD2 as a paradigm for understanding how epigenetic-regulator mutations drive tumorigenesis and how these mutations can be targeted. Our specific hypothesis for this application is that SETD2 mutations drive ccRCC in part by causing global DNA hypermethylation that promotes a more aggressive, metastatic gene expression program. In addition, we hypothesize that this class of ccRCCs is susceptible to DNA hypomethylating agents. We will address this hypothesis with three aims. In aim 1 we will characterize interactions between 5mC/DNMTs and H3K36me3 to define the mechanism by which SETD2 mutation drives aberrant 5mC targeting and gene expression. In aim 2 we interrogate how SETD2 mutation-mediated deregulation of 5mC and transcriptional patterns impact cell growth, metastasis, and susceptibility to epigenome-targeting agents. Finally in aim 3 we define 5mC signatures linked to EMT, and validate and characterize key 5mC deregulation events through which loss of H3K36me3 activity drives a metastatic gene expression program. Our studies will shed new light on how the genome and epigenome interact and yield a detailed picture of how mutation of an epigenetic regulator gene drives tumorigenesis. This is expected to positively affect human health by allowing for a more complete understanding of the molecular etiology underlying cancers with epigenetic regulator mutations and drive discovery of new therapies that specifically target the pathways they deregulate.