Restoration of Tumor Suppression Activity in Malignant Melanoma

描述(申请人提供)：我们的实验室已经证明，在原发恶性黑色素瘤中，S100B蛋白与野生型P53结合，解离P53四聚体，下调P53依赖的肿瘤抑制；因此，开发S100B-P53相互作用的抑制剂来恢复野生型P53在这种癌症中的活性是重要的。作为原理的证明，我们还证明了用小干扰反义RNA(SiRNASIOOB)抑制S100B可以恢复原发恶性黑色素瘤中野生型P53的肿瘤抑制活性。因此，我们假设可以合理地设计低分子化合物，以高亲和力结合S100B上明确的P53结合部位，并抑制S100B-P53的相互作用。这一假设将在拟议的研究中通过发现和合成具有以下具体目标的此类分子来进一步验证。在目标1中，计算机辅助药物设计(CADD)将与高通量/自动核磁共振、热力学结合和P53功能分析相结合，以发现与S100B结合并抑制S100B-P53相互作用的先导化合物。在目标2中，将使用核磁共振光谱和/或X射线结晶学来确定S100B-药物络合物的三维结构。这样的结构确定已经在进行中。在目标3中，将通过化学修饰来优化抑制S100B-p53相互作用的先导化合物。有机合成将以3D结构数据(来自AIM 2)和CADD主导优化方法为指导。将使用现有的热力学结合和生物分析(与目标1相同)对新的类似物进行测试。通过这一策略，我们的目标是发现/合成与S100B结合的新化合物，并恢复恶性黑色素瘤中的P53活性。在未来，最有希望的化合物将在动物模型中检验治疗黑色素瘤的疗效。这样的抑制剂很可能对其他S100B水平和野生型p53水平升高的癌症的治疗价值，如星形细胞瘤、肾肿瘤和白血病患者的恶性成熟T细胞。

DESCRIPTION (provided by applicant): Our lab has shown that the S100B protein binds to wild-type p53 in primary malignant melanoma, dissociates the p53 tetramer, and down-regulates p53-dependent tumor suppression; therefore, it is important to develop inhibitors of the S100B-p53 interaction to restore wild-type p53 activity in this cancer. As a proof of principle, we have also demonstrated that inhibiting S100B with small interfering antisense RNA (siRNASIOOB) restores wild-type p53 tumor suppressor activity in primary malignant melanoma. Accordingly, we hypothesize that low molecular weight compounds can be rationally designed to bind the well-defined p53 binding site on S100B with high affinity and inhibit the S100B-p53 interaction. This hypothesis will be tested further in the proposed study, via discovery and synthesis of such molecules with the following specific aims. In Aim 1, computer aided drug design (CADD), combined with high- throughput/automated NMR, thermodynamic binding and p53 functional assays will be used to discover lead compounds that bind S100B and inhibit the S100B-p53 interaction. In Aim 2, 3D structures of S100B-drug complexes will be determined using NMR spectroscopy and/or X-ray crystallography. Such structure determinations are already underway. In Aim 3, optimization of lead compounds that inhibit the S100B-p53 interaction will be performed via chemical modifications. Organic syntheses will be guided by 3D structural data (from Aim 2) and CADD lead optimization approaches. Testing of new analogues will be performed using existing thermodynamic binding and biological assays (as in Aim 1). With this strategy, it is our aim to discover/synthesize new compounds that bind S100B and restore p53 activity in malignant melanoma. In the future, the most promising compounds will be examined for efficacy in treating melanoma in animal models. Inhibitors such as these will likely have therapeutic value for treatment of other cancers that have elevated S100B levels and wild-type p53 such as astrocytomas, renal tumors and malignant mature T-cells in leukemia patients.