ASSESSING THE THERAPEUTIC WINDOW FOR FUTURE ANTI-NOTCH DIMERIZATION AGENTS

描述（由申请人提供）：异常Notch信号与癌症和其他人类疾病有关，这促使制药行业开发抑制Notch信号传导的药物。然而，对小鼠的研究预测，这些药物对各种器官系统都有毒性。在人类中证实的是胃肠道和皮肤的毒性，后者导致非黑色素瘤皮肤癌的发病率升高。我们已经证明，特异性靶向Notch 1除了增加癌症发病率外，还会导致血管肿瘤 如果这将发生在人类中，则将限制抗Notch 1疗法在慢性疾病环境中的治疗潜力。最近，我们和我们的合作者报道了活性Notch分子的二聚化是一些靶基因激活的重要步骤，并且是T细胞白血病（T-ALL）中Notch 1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，由于观察的新奇和缺乏可以区分二聚化依赖性靶标和非依赖性靶标的工具，在Notch信号传导中靶向这一方面的生物学后果目前是未知的。我们很幸运地获得了ARRA基金，开发了一种新技术，可以使用E. coli DNA腺嘌呤甲基转移酶（DAM）。这是一种理想的识别Notch二聚体依赖性靶点的新方法。在本申请中，我们提出通过定义治疗窗口（体内不良作用的范围），通过鉴定二聚化依赖性靶点（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性测定和高通量筛选来鉴定药物先导物，来促进用于“二聚体破坏”治疗的药物开发工作。

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.