Assay Development for NSD1 Methyltransferase Inhibitor Discovery

描述(由申请人提供)：尽管在过去的几十年里治疗取得了巨大的进步，但仍有一些儿科白血病的亚型非常难以治疗。一个引人注目的例子是一种特别侵袭性的急性髓系白血病(AML)，它是由基因NUP98(核孔蛋白，核孔复合体的98kd成分)和NSD1(核受体结合设定结构域蛋白1)的重排引起的。这种重排导致正常分离的NUP98和NSD1蛋白的融合。第一次NUP98-NSD1融合是在不到15年前被发现的，从那以后，很明显，这些遗传损伤经常被AML患者的常规基因测试遗漏。最近使用一种特殊检测方法的综合研究发现，携带NUP98-NSD1的AML存在于4-5%的儿童AML中，与10-30%的严峻的4年无事件生存率相关。因此，迫切需要专门针对这类儿科患者的新疗法。含有NUP98-NSD1融合的AML是通过激活特定致癌基因的表达而启动的，这导致正常的细胞分化过程失败，无法提供特定类型的血细胞。未分化的细胞获得了不受控制的增殖能力，而正是这种获得的“自我更新”能力是这些儿童白血病病例的关键触发因素。NSD1是一种甲基转移酶，通过将组蛋白中特定的赖氨酸残基甲基化来激活基因表达，影响它们与DNA的相互作用。因此，抑制NSD1酶活性的小分子应该能有效逆转导致AML的特定基因的激活，并使恶性细胞恢复到正常的分化形式。我们的目标是开发一套分析方法，以实现对数十万种化合物的高通量筛选，以发现NSD1酶的抑制剂，并对这些抑制剂进行表征，以确定选择性的化学探针，并引导候选药物作为针对儿童白血病NUP98-NSD1融合的分子疗法。

DESCRIPTION (provided by applicant): Despite dramatic treatment advances in the past few decades, there remain subsets of pediatric leukemia that are very difficult to treat. A striking example is a particularly aggressive type of acute myeloid leukemia (AML) caused by rearrangement of the genes NUP98 (nucleoporin, 98-kd component of nuclear pore complex) and NSD1 (nuclear receptor-binding SET domain protein 1). This rearrangement leads to fusion of the normally separate NUP98 and NSD1 proteins. The first NUP98-NSD1 fusion was identified less than fifteen years ago, and it has since become clear that these genetic lesions are often missed by routine genetic testing of AML patients. Recent comprehensive studies using a specific detection method found that AML harboring NUP98- NSD1 was present in 4-5% of pediatric AML, associated with a grim 4-year event-free survival rate of 10-30%. Thus novel therapies specifically targeted to this group of pediatric patients are urgently needed. AML harboring NUP98-NSD1 fusions is initiated through activation of the expression of specific cancer-causing oncogenes, which results in a failure of the normal process of cell differentiation to give specific types of blood cell. Undifferentiated cells acquire the ability to proliferate unchecked, and it is this acquired capacity for "self- renewal" that is the key trigger for these cases of pediatric leukemia. NSD1 is a methyltransferase enzyme that activates gene expression by methylating a specific lysine residue in histones, affecting their interaction with DNA. Therefore, small molecules that inhibit the enzyme activity of NSD1 should be effective in reversing activation of the specific genes causing AML and allow malignant cells to revert to a normal differentiated form. Our goal is to develop a suite of assays to enable high-throughput screening of several hundred thousand compounds to discover inhibitors of the NSD1 enzyme, and to characterize these inhibitors to identify selective chemical probes and lead candidates as molecular therapies targeted to childhood leukemia's harboring the NUP98-NSD1 fusion.