Inhibition of the ALK Receptor Kinase

描述(申请人提供)：分泌型生长因子多营养素(PTN)作用于内皮细胞、上皮细胞和成纤维细胞，可促进肿瘤生长、血管生成、侵袭和转移。最近，我们发现了PTN的一个受体，孤儿酪氨酸激酶间变性淋巴瘤激酶，ALK，它的激活域与胰岛素受体家族有同源性。ALK和PTN在大多数人类癌症样本中过度表达，而一系列正常组织中没有检测到受体的表达。核酶介导的ALK在胶质母细胞瘤和其他肿瘤细胞中的降低导致了“基因剂量”依赖的小鼠移植瘤生长的减少，并支持ALK作为药物发现的有效靶点。最近，我们在培养细胞中发现了在纳摩尔浓度下抑制PTN刺激的ALK激酶的小分子药物，并使用同源建模来生成这些候选药物的蛋白质的3D模型。我们假设有可能发现新的选择性抑制剂，并提出以下目标：目标1，先导鉴定：我们将通过从头药物设计、文库筛选和虚拟组合文库生成，在电子计算机中鉴定新的ALK激酶抑制剂。最好的候选者将被合成用于生物检测。目的2，研究这些候选抑制剂对PTN刺激的ALK激酶活性的抑制作用，并与其他生长因子诱导的受体激酶活性进行比较。然后将使用这些数据进行额外的分子建模来设计和优化抑制剂。目标3，先导优化：通过进一步完善药物/蛋白质相互作用的分子模型，改进生物测定中产生的先导化合物。然后，这些新的抑制剂将被测试以对抗PTN刺激的完整细胞中的ALK激酶活性。目的：研究最佳抑制物对细胞生长的抑制作用。与阻断其他生长因子相比，选定的PTN刺激的ALK激酶抑制剂将测试它们阻止PTN诱导的细胞增殖、抗凋亡和软琼脂集落形成的能力。总之，我们建议设计和研究基于结构的PTN/ALK信号抑制剂，作为生物学和分子模拟/化学实验室之间的密切合作，目的是为了发现新的抗癌药物。

DESCRIPTION (provided by applicant): The secreted growth factor pleiotrophin (PTN) acts on endothelial as well as epithelial cells and fibroblasts and it can drive tumor growth, angiogenesis, invasion as well as metastasis. Recently, we identified a receptor for PTN, the orphan tyrosine kinase anaplastic lymphoma kinase, ALK that shares homology of its kinase domain with the insulin receptor family. ALK and PTN are overexpressed in a majority of human cancers samples whilst a series of normal tissues showed no detectable receptor expression. Ribozyme-mediated reduction of ALK in glioblastoma and other tumor cells resulted in a "gene dose"-dependent reduction of xenograft tumor growth in mice and supports ALK as a valid target for drug discovery. Recently we identified small-molecule drugs that inhibit the PTN-stimulated ALK kinase in cultured cells at nanomolar concentrations and we used homology modeling to generate a 3D model of the protein with these drug candidates. We hypothesize that it will be possible to identify novel selective inhibitors and propose the following aims: Aim 1, Lead identification: We will identify in silico novel ALK kinase inhibitors using de novo drug design, library screening and virtual combinatorial library generation. The best candidates will be synthesized for the biologic assays. Aim 2, to study the inhibition of PTN-stimulated ALK kinase activity in comparison to other growth factor-induced receptor kinase activity by these candidate inhibitors. Additional molecular modeling using these data will then be used to design and optimize inhibitors. Aim 3, Lead optimization: To improve lead compounds emanating from the biologic assays by further refinement of the molecular modeling of drug / protein interaction. These new inhibitors will then be assayed against PTN-stimulated ALK kinase activity in intact cells. Aim 4: To study the efficacy and potency of the best inhibitors on cell growth. Selected inhibitors of the PTN-stimulated ALK kinase will be tested for their ability to block PTN-induced cell proliferation, anti-apoptosis and soft agar colony formation in comparison to their blockade of other growth factors. In summary, we propose the design and study of structure-based inhibitors of the PTN/ALK signaling as a close collaboration between a biology and a molecular modeling/chemistry laboratory with the purpose of discovering novel anticancer drugs.