ASSESSING THE THERAPEUTIC WINDOW FOR FUTURE ANTI-NOTCH DIMERIZATION AGENTS

描述(申请人提供)：异常的Notch信号与癌症和其他人类疾病有关，这促使制药业开发抑制Notch信号的药物。然而，在老鼠身上进行的研究预测，这些制剂将对各种器官系统产生毒性。在人类中证实了对胃肠道和皮肤的毒性，后者会导致非黑色素瘤皮肤癌的发病率上升。我们已经证明，靶向Notch1除了会增加癌症的发病率外，还会导致血管肿瘤 在皮肤中；如果这将发生在人类身上，它将限制抗Notch1疗法在慢性病环境中的治疗潜力。最近，我们和我们的合作者报道，活性Notch分子的二聚化是一些靶基因激活的重要步骤，是T细胞白血病(T-ALL)Notch1致癌活性所必需的。T-ALL对Notch二聚化的绝对依赖性提供了一种新的基于机制的治疗途径。然而，由于观察的新颖性以及缺乏区分二聚化依赖靶点和独立靶标的工具，在Notch信号转导中靶向这一方面的生物学后果目前尚不清楚。我们很幸运地获得了ARRA的资金，以开发一种新技术，该技术可以使用大肠杆菌DNA腺嘌呤甲基转移酶(DAM)的互补片段来询问不同多成员复合体的靶标选择。这是一种识别Notch二聚化依赖靶的理想的新方法。在这项申请中，我们建议通过定义治疗窗口(体内不良反应的频谱)、识别二聚依赖靶点(如果该窗口被证明太窄或药物发现工作太困难)以及通过利用我们的二聚体敏感分析和高通量筛选来识别药物先导，来促进‘破坏二聚体’疗法的药物开发工作。

DESCRIPTION (provided by applicant): Aberrant Notch signals have been linked to cancer and other human diseases, which has motivated the pharmaceutical industry to develop agents inhibiting Notch signaling. However, studies in the mouse predicted that these agents would be toxic to various organ systems. Confirmed in humans are toxicities to the gastrointestinal track and skin, the latter leading to elevated rates of non-melanoma skin cancer. We have shown that targeting Notch1 specifically will result in vascular tumors in addition to increasing cancer rates in the skin; if this will occur in humans it will limit the therapeutic potential of anti-Notch1 therapies in a chronic disease setting. Recently, we and our collaborators reported that dimerization of active Notch molecules is an important step in the activation of some target genes and is required for the oncogenic activity of Notch1 in T-cell leukemia (T-ALL). The absolute dependence of T- ALL on Notch dimerization provides a novel mechanism-based therapeutic avenue. However, the biological consequences of targeting this aspect in Notch signaling are currently unknown due to novelty of the observation and the lack of tools that can differentiate dimerization-dependent from -independent targets. We were fortunate to be awarded ARRA funds to develop a new technology that can interrogate target selection by different multi-member complexes using complementing fragments of the E. coli DNA Adenine methyltransferase (DAM). It is an ideal novel method to identify Notch dimerization dependent targets. In this application we propose to facilitate drug development efforts for 'dimer-busting' therapeutics by defining the therapeutic window (the spectrum of untoward effects in vivo), by identifying dimerization dependent targets (should this window prove to be too narrow or the drug discovery efforts too difficult) and by utilizing our dimer-sensitive assay and high throughput screening to identify drug leads.