Maximal MYC control using dual PI-3K/BRD4 (kinase/epigenetic) inhibitors

描述（由申请人提供）：抑制关键的促癌转录因子MYC的需求尚未得到满足。MYC（cMYC和MYCN）作用于许多细胞受体复合物和信号转导通路的下游，以激活驱动癌细胞生长和增殖的基因。迄今为止，MYC的小分子抑制剂一直难以捉摸。一种创新的方法将是通过使用PI-3激酶（PI-3 K）抑制剂增强其降解并结合使用溴结构域蛋白BRD 4的抑制剂阻断产生MYC的基因的转录来间接正交地降低MYC的活性。虽然小分子抑制剂或PI-3 K和BRD 4单独用于癌症临床试验，但没有一种药物通过FDA的批准。尽管联合治疗在癌症中很常见，但对每种增加的组合抑制多个靶点以使功效最大化的需求仍未得到满足。这变得不可行，因为当组合昂贵的靶向治疗时，除了对这种复杂的药物组合的早期临床评价构成障碍之外，还存在过高的成本。在探索新型PI-3 K抑制剂支架，基于色酮衍生物的噻吩并吡喃酮（TP）支架时，我们发现这些化合物也可以有效抑制BRD 4（初步结果）。色酮骨架对于两种靶标的抑制是共同的，因此提供了现在探索新发现的BRD 4活性同时保持有效的PI-3 K活性的机会（总体目标）。巩固PI-3 K和BRD 4的抑制以用一个分子最大限度地抑制MYC活性将满足上述所有未满足的需求。本提案将通过实现以下目标来评估该方法，为II期工作奠定基础，以将预期的双重抑制剂先导化合物优化为临床候选化合物：目标（任务）#1。测定TP化合物对BRD 4抑制的构效关系（SAR）。方法：合成30个TP化合物，并测定其BRD 4和PI-3 K抑制谱。目标（任务）#2。开发预测性计算BRD 4模型，用于设计化合物的计算机对接。方法：改变BRD 4模型的分子计算机模拟拟合参数，直至TP数据集的对接预测与实际BRD 4测定结合结果相关，从而创建经验证的对接模型。目标（任务）#3。确定双重BRD 4/PI-3 K抑制对MYC和治疗指数的影响。方法：测定MYC表达和活性水平，并比较当暴露于单一BRD 4或PI-3 K与双重BRD 4/PI-3 K抑制条件时对癌细胞系与正常细胞系的毒性。这项研究的贡献是它提供了一种有效的机制来阻断MYC活性，这种活性驱动癌症，并且将是重要的，因为它将允许增强MYC依赖性癌症的联合治疗，如CLL，髓母细胞瘤和神经母细胞瘤。这种方法是创新的，因为它使用单一化合物的两种正交机制来攻击关键的癌症靶标，并且它挑战了在没有FDA批准的治疗方法的癌症研究中普遍存在的一药一靶的成本忽视疗效限制心态。

DESCRIPTION (provided by applicant): There is an unmet need to inhibit the key cancer promoting transcription factor MYC. MYC (both cMYC and MYCN) acts downstream of many cell receptor complexes and signal transduction pathways to activate genes that drive cancer cell growth and proliferation. To date, small molecule inhibitors of MYC have been elusive. An innovative approach would be to indirectly orthogonally diminish the activity of MYC by enhancing its degradation using PI-3 kinase (PI-3K) inhibitors combined with blocking transcription of the gene producing MYC using inhibitors of the bromodomain protein BRD4. While small molecule inhibitors or PI-3K and BRD4 are individually used in cancer clinical trials, none has made it through development to FDA approval. Although combination treatments are common in cancer, there is an unmet need for every increasing combinations to inhibit multiple targets to maximize efficacy. This becomes unfeasible due to prohibitive costs when combining expensive targeted therapies in addition to being a barrier to early clinical evaluation of such complex combinations of drugs. While exploring a novel PI-3K inhibitor scaffold, thienopyranone (TP) scaffold based on a chromone derivative we discovered that these compounds also can potently inhibit BRD4 (preliminary results). The chromone backbone is common to the inhibition of BOTH targets thus providing the opportunity to now explore the newly found BRD4 activity while maintaining potent PI-3K activity (overall objective). Consolidating the inhibition of PI-3K AND BRD4 to maximally inhibit MYC activity with one molecule would fill all the unmet needs stated above. This proposal will evaluate this approach by achieving the following aims setting the stage for phase II efforts to optimize the expected dual inhibitor lead compound(s) to a clinical candidate: Aim (Task) #1. Determine structure activity relationship (SAR) for TP compounds for BRD4 inhibition. Approach: Synthesize 30 TP compounds and determine their BRD4 and PI-3K inhibition profiles. Aim (Task) #2. Develop predictive computational BRD4 model for the in silico docking of designed compounds. Approach: Vary the molecular in silico fit parameters of the BRD4 model until docking predictions of a TP dataset correlates with actual BRD4 assay binding results creating a validated docking model. Aim (Task) #3. Determine effects on MYC and therapeutic index for dual BRD4/PI-3K inhibition. Approach: Determine MYC expression and activity levels and compare toxicity towards cancer cell lines versus normal cell lines when exposed to single BRD4 or PI-3K versus dual BRD4/PI-3K inhibition conditions. The contribution of this research is it provides an effective mechanism to block MYC activity that drives cancer and will be significant because it will allow enhanced combination treatments of MYC dependent cancers, such as CLL, medulloblastoma, and neuroblastoma. This approach is innovative because it attacks a key cancer target using two orthogonal mechanisms with a single compound and it challenges the cost-ignoring efficacy-limiting mentality of one-drug one-target prevalent in cancer research in an area with no FDA approved treatments.