Identification of potent and selective GLI1 inhibitors

描述(由申请人提供)：结合动物模型中的抑制剂研究，对人类肿瘤样本和细胞系的表征已经确立了 HH通路在多种癌症类型中均有表达，包括小细胞肺癌、胰腺癌、食道癌、前列腺癌、乳腺癌、结肠癌、肝癌和卵巢癌。目前，大约20-25%的癌症与HH信号有关。Gli1是HH信号通路的下游效应分子，已成为有效的治疗靶点。由于HH通路中信号输入的复杂性，靶向GLI1可能为治疗典型和非典型HH通路依赖的癌症提供了一种更全面的策略。鉴于患者对SMO抑制剂的获得性耐药，情况尤其如此。利用GLI1依赖的转录报告细胞分析的筛选已经产生了靶向SMO下游HH途径的抑制剂，包括小分子和通过不同作用机制靶向GLI1的天然产物化合物。用小分子靶向GLI1水平在包括结肠癌、CLL和乳腺癌在内的许多癌症模型系统中都是有效的。然而，这些化合物在体外只有微摩尔效力，其中一个亚组(GANT61和ATO)在体内癌症模型中仅显示出适度的疗效。这些研究表明，GLI1在药理学上是有靶向性的，使用GLI1抑制剂是一种有效和有前途的靶向GLI1依赖肿瘤的方法。不幸的是，目前的GLI1抑制剂效力低，缺乏体内疗效，因此不是可行的临床候选药物。临床上没有GLI1靶向抑制剂。使用一种新的高通量、高含量的基于细胞的成像平台，我们将筛选不同的小分子集合，以确定GLI1的有效抑制剂(目标1)。显示抑制活性的化合物将在一个专注的基于细胞的分析小组中进一步验证，该小组将包括来自原发人类乳腺肿瘤的细胞。这些化验还将检查化合物的选择性及其对移动性/侵入性的影响(目标2)。在目标1和目标2中发现的有前景的化合物将受到广泛的构效关系的影响，以优化新型GLI1抑制剂(目标3)。

DESCRIPTION (provided by applicant): Characterization of human tumor samples and cell lines in combination with inhibitor studies in animal models has established a central role for the Hh pathway in a vast array of cancer types, including small-cell lung, pancreatic, oesophageal, prostate, breast, colon, liver and ovarian cancers. Hh signaling is now implicated in approximately 20-25% of all cancers. GLI1 is the downstream effector in the Hh signaling pathway, and has emerged as a valid therapeutic target. It has been suggested that due to the complexity of signaling inputs in the Hh pathway, targeting GLI1 may provide a more comprehensive strategy for treating both canonical and noncanonical Hh-pathway dependent cancers. This is especially true in light of the acquired resistance to inhibitors of SMO in patients. Screens utilizing GLI1-dependent transcriptional reporter cell-based assays have yielded inhibitors targeting the Hh pathway downstream of SMO including small molecule and natural product compounds that act by targeting GLI1 through differing mechanisms of action. Targeting at the level of GLI1 with small molecules has been effective in a number of cancer model systems including colon, CLL and breast cancer. However, these compounds have only micromolar potencies in vitro, and a subset (GANT61 and ATO) has shown only modest efficacy in in vivo cancer models. These studies suggest that GLI1 is pharmacologically targetable, and that the use of GLI1 inhibitors is a valid and promising approach for targeting GLI1-dependent cancers. Unfortunately, current GLI1 inhibitors are hampered by low potency and a lack of in vivo efficacy and hence are not viable clinical candidates. There are no GLI1-targeted inhibitors in the clinic. Using a novel high throughput, high content cell-based imaging platform, we will screen a diverse collection of small molecules to identify potent inhibitors of GLI1 (Aim 1). Compounds that show inhibitory activity will be further validated in a focused panel of cell-based assays which will incorporate cells derived from primary human breast tumors. These assays will also examine selectivity of the compounds as well as their effects on motility/invasiveness (Aim 2). Promising compounds discovered in Aims 1 and 2 will be subjected to extensive structure-activity relationship to optimize the novel GLI1 inhibitors (Aim 3).