Targeting proapoptotic PKCdelta signaling in hepatocellular carcinoma

描述(申请人提供)：肝细胞癌是世界范围内的主要死亡原因，在美国的发病率正在迅速上升。目前，对于大部分患有晚期、不可切除疾病的肝细胞癌患者的系统治疗基本上是不成功的，因此，有必要为这种疾病开发有效的、延长生命的治疗策略。PI的实验室投入了重要的资源来开发新的口服小分子药物，这些药物针对肝癌细胞中的分子和细胞缺陷，使这种疾病的临床治疗变得如此具有挑战性。在本项目中，我们以免疫抑制剂FTY720为支架，对一类新型的蛋白激酶C(PKC)d靶向药物进行了机理研究和结构优化。这项研究源于我们的机制发现，FTY720通过促进ROS-PKCd信号的激活而触发肝癌细胞的凋亡。本研究的重点是：(1)对FTY720进行结构优化和最优衍生物的机制验证；(2)评价结构优化的(S)-FTY2衍生物抑制肝癌移植瘤生长的体内效应。在目标1中，FTY720的先导优化旨在将FTY720的免疫抑制活性从其对ROS-PKCd信号的影响中分离出来。(S)-FTY2是这方面的先导化合物，然后将使用生物测定指导的两级策略进行结构优化，包括细胞存活分析和Western blotting，以筛选基于(S)-FTY2的化合物文库，以产生有效的PKCd靶向试剂。在目标2中，将在原位和异位异种移植瘤模型中检验最佳衍生物在体内抑制肝癌肿瘤生长的效果。我们期望所提出的研究将产生支持我们的假设的数据，即通过小分子药物靶向ROS-PKCd信号转导代表了一种与治疗相关的治疗肝癌的方法，并最终导致新的方法将改善肝癌的治疗并增加肝癌患者的生存。公共卫生相关性：肝细胞癌是世界范围内的主要死亡原因，在美国的患病率正在迅速上升。我们的总体研究目标是开发新的治疗药物，针对肝癌细胞中的分子和细胞缺陷，这些缺陷使这种疾病的临床治疗变得如此具有挑战性。我们预计，该项目最终将产生新的药物，改善肝癌的治疗，提高肝癌患者的存活率。

DESCRIPTION (provided by applicant): Hepatocellular carcinoma (HCC) is a leading cause of death worldwide, and is rapidly increasing in prevalence in the United States. Current systemic therapies for the large proportion of HCC patients with advanced, nonresectable disease have been largely unsuccessful; thus, a clear need exists to develop effective, life- prolonging therapeutic strategies for this disease. The PI's laboratory has devoted vital resources to developing novel oral, small-molecule agents that target the molecular and cellular defects in HCC cells that make the clinical management of this disease so challenging. In this project, we focus on the mechanistic investigation and structural optimization of a novel class of protein kinase C (PKC)d-targeted agents by using FTY720, an immunosuppressive agent, as a scaffold. This study stems from our mechanistic finding that FTY720 triggers apoptosis in HCC cells by facilitating the activation of ROS-PKCd signaling. The following aims constitute the foci of this investigation: (1) to conduct structural optimization of FTY720 and mechanistic validation of optimal derivatives; and (2) to assess the in vivo effect of structurally optimized (S)-FTY2 derivatives on suppressing HCC xenograft growth. In Aim 1, lead optimization of FTY720 is directed at separating the immunosuppressive activity of FTY720 from its effects on ROS-PKCd signaling. (S)-FTY2, which represents a lead compound in this regard, will then be structurally optimized using a bioassay-guided, two-tiered strategy involving cell survival assays and Western blotting to screen against a (S)-FTY2-based compound library to generate potent PKCd-targeted agents. In Aim 2, the in vivo efficacies of optimal derivatives in suppressing the growth of HCC tumors will be examined in both orthotopic and ectopic xenograft tumor models. We expect the proposed studies to yield data in support of our hypothesis that targeting ROS- PKCd signaling by small-molecule agents represents a therapeutically relevant approach to treat HCC, and ultimately lead to new approaches that will improve the treatment of HCC and increase the survival of HCC patients. PUBLIC HEALTH RELEVANCE:Hepatocellular carcinoma (HCC) is a leading cause of death worldwide, and is rapidly increasing in prevalence in the United States. Our overall research goal is to develop novel therapeutic agents that target the molecular and cellular defects in HCC cells that make the clinical management of this disease so challenging. We expect that this project will ultimately yield new drugs that will improve the treatment of HCC and increase the survival of HCC patients.