AN INTEGRATED PLATFORM FOR NOVEL PERSONALIZED LIVER CANCER THERAPEUTICS

摘要 肝癌是全球癌症相关死亡的第四大原因。目前，除了 新兴的免疫检查点抑制剂，少数结构相关的激酶抑制剂（KI） 批准用于治疗晚期肝细胞癌（HCC），这是最常见的肝癌形式。虽然重要， 这些药物可以适度改善生存（通常是几个月），而且往往要付出显着的代价 毒性。索拉非尼、瑞戈非尼、卡博替尼和乐伐替尼这些药物都是多靶点 KI，但效果较差。 明确的行动机制。因此，这些药物给予 HCC 患者时没有考虑到 肿瘤内的特异性突变。这是一个艰巨的挑战；没有明确的目标和机制，就不可能 存在明确的路径来指导 HCC 改进疗法的开发。 在这个提案中，我们结合化学生物学方法来修改临床的目标偏好 批准 HCC KI 和表观遗传工具化合物，我们开发精准基因工程小鼠 模型和 3D 肿瘤类器官在一个集成平台中，以确定新的药物靶点和治疗方法 肝癌。我们的初步数据表明，不同的基因组驱动因素建立了独特的表观基因组景观 在肿瘤类器官线内，影响可药物空间。通过化学遗传筛选，我们有 鉴定出的先导化合物要么在所有测试的 HCC 基因型中具有泛活性，要么有一些是 对特定遗传背景具有选择性（例如 WNTinib1 用于 WNT/β-Catenin 驱动的肿瘤）。通过结合 WNTinib1 的化学、蛋白质组和靶点参与数据，我们已经确定了 Ezh2 的独特 p38a/b 信号轴作为拮抗突变β-连环蛋白活性的关键和选择性依赖性。主要 我们试图测试的假设是独特的表观基因组景观和对信号传导的依赖性 由不同的 HCC 癌症驱动因素建立的途径赋予对特定目标的不同敏感性 和小分子。通过利用驱动诱导的癌症小鼠模型、小鼠和人类肿瘤 类器官和患者来源的异种移植物（PDX），我们将能够建议分层策略并确定 更有效的 HCC 定制疗法。该提案的长期目标是确定并描述 在机制层面上，信号通路和靶标能够实现 (i) 跨多种 HCC 的泛活性 亚型，(ii) 在特定突变驱动的肿瘤背景下的选择性活性，(iii) 协同肿瘤 抑制与免疫治疗方法相结合。重要的是，我们已经确定了强大的小分子 包括 WNTinhib1 在内的先导药物在多种 HCC 中表现出优于标准护理 KI 的功效 模型，包括人体样本。 主要交付成果包括从经过充分验证的化学起始衍生的药物发现新工具和线索 HCC 患者分层和治疗的要点和机制见解。

SUMMARY Liver cancer is the fourth leading cause of cancer related mortality worldwide. Currently, in addition to emerging immune checkpoint inhibitors, a small number of structurally related kinase inhibitors (KIs) are approved for advanced hepatocellular carcinoma (HCC), the most frequent form of liver cancer. While important, these drugs provide modest improvements in survival— typically months—and often at the cost of significant toxicity. The drugs, sorafenib, regorafenib, cabozantinib and lenvatinib are all multi-targeted KIs with poorly defined mechanisms of action. As such, these drugs are given to HCC patients without any consideration to a specific mutation within tumors. This presents a daunting challenge; without a clear target or mechanism, no clear path exists to guide the development of improved therapies for HCC. In this proposal, we combine chemical biology approaches to modify target preferences of clinically approved HCC KIs and epigenetic tool compounds, and we develop precision genetically-engineered mouse models and 3D tumor organoids in an integrated platform to identify new drug targets and therapeutics for HCC. Our preliminary data demonstrate that different genomic drivers establish unique epigenomic landscapes within tumor organoid lines, influencing the druggable space. Through chemical genetic screens, we have identified lead compounds that are either pan-active across all HCC genotypes tested and some which are selective to specific genetic backgrounds (e.g. WNTinib1 for WNT/β-Catenin driven tumors). By combining chemical, proteomic, and target engagement data for WNTinib1, we have identified an unique p38a/b to Ezh2 signalling axis as a key and selective dependency to antagonize the activity of mutant β-Catenin. The major hypothesis that we seek to test is that the unique epigenomic landscapes and dependencies on signaling pathways, which are established by different HCC cancer drivers, confer differential sensitivity to specific targets and small molecules. By taking advantage of driver-induced cancer mouse models, murine and human tumor organoids, and patient-derived xenografts (PDXs), we will be able to suggest stratification strategies and identify more effective tailored therapeutics for HCC. The long-term goal of this proposal is to identify and characterize at the mechanistic level, the signaling pathways and targets that enable (i) pan-activity across a variety of HCC sub-types, (ii) selective activity in the context of tumors driven by specific mutations, (iii) synergistic tumor inhibition in combination with immunotherapy approaches. Importantly, we have identified strong small molecule leads, including WNTinhib1, that display superior efficacy compared to standard-of-care KIs across several HCC models, including human samples. Key deliverables include new tools and leads for drug discovery derived from well-validated chemical starting points and mechanistic insights into patient stratification and therapeutics for HCC.