Identification of novel epigenetic modulators of CBP-like bromodomains for the analysis of their therapeutic potential

表观遗传机制是指在不改变DNA序列的情况下发生的基因活性的可遗传变化。这些非遗传改变受到与DNA相关的组蛋白的严格调控。特定的编写器和橡皮擦蛋白修饰组蛋白尾部的残基，这些残基又被组蛋白尾部阅读器蛋白识别。在功能上，表观遗传修饰的模式被翻译成受调控的表达水平，从而在细胞周期中作为基因表达和染色质组织的表观遗传标记。包括癌症在内的几种人类疾病表现出受表观遗传调节器活动水平变化影响的信号通路改变。因此，这些蛋白质的医学相关性使这些过程的药理学操作成为一个密集的研究领域。最近，溴结构域和末端外(BET)溴结构域家族乙酰化阅读器的小分子抑制剂在基因定义的中线癌和血液系统恶性肿瘤的治疗中显示出早期的希望。除了BET家族，还有数十个其他溴域的治疗潜力往往尚未被发现。例如，类似CBP的家族包含六个密切相关的溴域成员。对于它们中的一些在恶性肿瘤中的作用仍然难以捉摸，而对于另一些，至于同名的CREB结合蛋白(CBP)本身，有明确的迹象表明它们作为新的治疗靶点具有很高的潜力。然而，在寻找针对CBP样家族的有效抑制剂方面只取得了很小的成功。因此，识别抑制该家族溴结构域的小分子是最重要的，也是本研究项目的目的。该项目将首先通过对CBP类家族的所有六个成员进行大规模的基于片段的电子筛选来初步选择候选分子。我们可以在以前的工作中识别出一个高度有效的片段，它将作为这些筛选的起点。该项目将继续使用等温滴定量热法对预测进行实验验证，并对已识别的新化合物及其目标络合物进行结晶和X射线结构分析。所获得的数据将是通过基于模型的先导优化来优化对高亲和力粘结剂的命中的基础。治疗潜力将通过对相关细胞系的体外测试来进一步分析。这项分析将得到基因表达谱的补充，以评估新发现的抑制剂对细胞的影响。最后，该项目将有助于提供针对目前难以治愈甚至无法治疗的恶性肿瘤的新药。

Epigenetic mechanisms are heritable changes in gene activity that occur without alteration in DNA sequence. These non-genetic alterations are tightly regulated by histone proteins associated with DNA. Specific writer and eraser proteins modify residues of the histone tails which are in turn recognised by histone tail reader proteins. Functionally, the patterns of epigenetic modifications are translated into modulated expression levels and thus serve as epigenetic markers for gene expression and chromatin organisation during the cell cycle. Several human diseases, including cancer, show altered signalling pathways affected by changes in the activity levels of epigenetic modulators. Consequently, the medical relevance of these proteins has made the pharmacological manipulation of these processes an area of intense research. Recently, small-molecule inhibitors for the bromodomain and extra-terminal (BET) bromodomain family of acetylation readers have shown early promise in the treatment of the genetically defined midline carcinoma and hematopoietic malignancies. In addition to the BET family, there are dozens of other bromodomains whose therapeutic potential has often not been discovered yet. The CBP-like family for instance contains six members of closely related bromodomains. For some of them the role in malignancies remains elusive, while for others, as for the eponymous CREB-binding protein (CBP) itself, there are clear indications for their high potential as novel therapeutic targets. However, only little success was made in identifying potent inhibitors against the CBP-like family. The identification of small molecules inhibiting the bromodomains of this family is therefore of prime importance and the very aim of this research project. The project will start with the initial selection of candidate molecules by large-scale fragment-based in silico screenings to all six members of the CBP-like family. A highly-potent fragment, which we could identify in our previous work, will serve as starting point for these screenings. The project will continue with the experimental validation of the predictions using isothermal titration calorimetry, and crystallisation and X-ray structure analysis of the identified novel compounds in complex with their targets. The obtained data will be the basis for the optimisation of the hits toward high-affinity binders via model based lead optimisation. The therapeutical potential will be further analysed by in vitro tests on relevant cell lines. The analysis will be complemented by gene expression profiling to assess the impact of newly identified inhibitors on the cell. Finally, the project will contribute to providing new drugs against currently only hardly or even non-treatable malignancies.