Novel NFAT1-MDM2 inhibitor for Breast Cancer Therapy

本项目的长期目标是开发一种新的双靶向治疗策略（MDM 2和 NFAT 1）用于治疗晚期乳腺癌。晚期乳腺癌患者，尤其是 患有三阴性乳腺癌（TNBC）的患者不能从最近开发的靶向治疗中获益。 越来越多的证据表明，几个关键信号通路的功能障碍，包括 NFAT 1-MDM 2通路与不良预后和化疗/放射抗性相关，提供了新的治疗方法。 乳腺癌治疗的分子靶点。MDM 2癌基因是p53的主要负调节因子， 也具有p53非依赖性致癌活性。它被认为是乳腺癌治疗的有效分子靶点 癌症治疗迄今为止，大多数MDM 2的小分子抑制剂（SMI）已被设计成 阻断MDM 2与p53的结合，因此它们的抗癌活性依赖于 癌细胞中的野生型p53。然而，大多数TNBC携带突变型p53，并且具有高水平的 MDM 2，因此预期现有MDM 2 SMI对该乳腺癌亚型的疗效较低或无疗效 癌因此，非常需要发现和开发具有直接作用的新型MDM 2抑制剂， 在MDM 2上，并独立于癌细胞的p53状态发挥其抗癌活性。的激活 NFAT 1也常在乳腺癌中观察到，特别是在TNBC中，促进了乳腺癌的发展。 侵袭性、高级别和晚期肿瘤表型。因此，申请人提出NFAT 1作为一种新颖的 用于开发抗乳腺癌药物的靶点。到目前为止，还没有特异性的NFAT 1抑制剂 用于癌症治疗。具体到这一建议，申请人最近发现，NFAT 1 在癌细胞和癌组织中上调MDM 2表达并导致MDM 2过表达， 包括乳腺癌根据新生成的初步数据，申请人同时提出 靶向NFAT 1和MDM 2作为晚期乳腺癌的有前途的治疗策略。申请人 最近完成了对基于天然产物的库的高通量筛选，并确定了 一系列对NFAT 1和MDM 2都具有有效抑制作用的二倍半萜类候选物。之一 先导化合物Japonicone A（JapA）已显示出显著体外活性、体内功效和最小宿主 乳腺癌模型中的毒性。在机制上，JapA直接结合MDM 2和NFAT 1蛋白， 高亲和力，并诱导MDM 2和NFAT 1蛋白不稳定性。它还抑制NFAT 1介导的MDM 2 通过破坏NFAT 1与MDM 2 P2启动子的结合来转录。这种一流的MDM 2抑制剂是 与所有现有的MDM 2抑制剂不同。在此修订后的提案中，申请人将以JapA为主导 化合物来测试中心假设，即双重靶向MDM 2和NFAT 1代表了有效的且 治疗晚期乳腺癌的安全策略。三个假设驱动的具体目标是 提出：1）证明JapA对晚期乳腺癌的治疗潜力; 2）阐明 JapA作为特异性NFAT 1-MDM 2双重抑制剂发挥抗乳腺癌活性的分子机制 抑制剂;和3）表征JapA的药理学和毒理学性质。完成后 拟议的研究，预期的结果将提供有关治疗效果的关键信息， JapA的安全性以及同时靶向MDM 2和NFAT 1在乳腺癌中的价值。这个项目是 高度显著，具有高翻译潜力，并将产生一种新的乳腺癌临床候选药物 这将对病人护理和公共卫生产生重大影响。

The long-term objective of this project is to develop a novel dual-targeting therapeutic strategy (MDM2 and NFAT1) for the treatment of advanced breast cancer. Patients with advanced breast cancer, especially those with triple negative breast cancer (TNBC), cannot benefit from the recently-developed targeted therapies. Accumulating evidence has demonstrated that the dysfunction of several key signaling pathways, including NFAT1-MDM2 pathway, is associated with a poor prognosis and chemo-/radio-resistance, providing novel molecular targets for breast cancer therapy. The MDM2 oncogene is a major negative regulator of p53 and also has p53-independent oncogenic activity. It has been suggested to be a valid molecular target for breast cancer therapy. To date, the majority of small molecule inhibitors (SMIs) of MDM2 have been designed to block the binding of MDM2 to p53, and their anticancer activity was therefore dependent on the expression of wild-type p53 in the cancer cells. However, the majority of TNBC harbors mutant p53 and has high levels of MDM2, so the existing MDM2 SMIs are expected to have low or no efficacy against this subtype of breast cancer. Therefore, it is highly desirable to discover and develop novel MDM2 inhibitors that have direct effects on MDM2 and exert their anticancer activity independent of the p53 status of the cancer cells. The activation of NFAT1 is also commonly observed in breast cancers, especially in TNBC, promoting the development of an invasive, high-grade, and late-stage tumor phenotype. Therefore, the applicants propose NFAT1 as a novel target for the development of anti-breast cancer agents. Thus far, there has been no specific NFAT1 inhibitors developed for cancer therapy. Specific to this proposal, the applicants have recently discovered that NFAT1 up-regulates MDM2 expression and contributes to MDM2 overexpression in cancer cells and cancer tissues, including breast cancer. Based on newly-generated preliminary data, the applicants propose simultaneously targeting NFAT1 and MDM2 as a promising therapeutic strategy for advanced breast cancer. The applicants have recently accomplished a high-throughput screening of a natural product-based library, and have identified a series of disesquiterpenoid candidates with potent inhibitory effects on both NFAT1 and MDM2. One of the lead compounds, Japonicone A (JapA), has shown significant in vitro activity, in vivo efficacy, and minimal host toxicity in breast cancer models. Mechanistically, JapA directly binds to the MDM2 and NFAT1 proteins with high affinity, and induces MDM2 and NFAT1 protein instability. It also inhibits NFAT1-mediated MDM2 transcription by disrupting the binding of NFAT1 to the MDM2 P2 promoter. This first-in-class MDM2 inhibitor is distinct from all of the existing MDM2 inhibitors. In this revised proposal, the applicants will use JapA as a lead compound to test the central hypothesis that the dual targeting MDM2 and NFAT1 represents an effective and safe strategy for the treatment for advanced breast cancer. Three hypothesis-driven specific aims are proposed: 1) To demonstrate the therapeutic potential of JapA for advanced breast cancer; 2) To elucidate the molecular mechanisms by which JapA elicits anti-breast cancer activity as a specific NFAT1-MDM2 dual inhibitor; and 3) To characterize the pharmacological and toxicological properties of JapA. Upon completion of the proposed studies, the anticipated results will provide critical information about the therapeutic efficacy and safety of JapA and the value of simultaneously targeting MDM2 and NFAT1 in breast cancer. This project is highly significant, has high translational potential, and will generate a novel clinical candidate for breast cancer therapy, which would have a major impact on patient care and public health.