Targeting proapoptotic PKCdelta signaling in hepatocellular carcinoma

描述（由申请人提供）：肝细胞癌（HCC）是世界范围内的主要死亡原因，在美国的患病率迅速增加。目前对大部分患有晚期不可切除疾病的HCC患者的全身治疗在很大程度上是不成功的;因此，明确需要开发针对该疾病的有效的、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，这些药物靶向HCC细胞中的分子和细胞缺陷，这些缺陷使得这种疾病的临床管理具有挑战性。在这个项目中，我们专注于一类新的蛋白激酶C（PKC）d靶向药物的机制研究和结构优化，使用FTY 720，免疫抑制剂，作为支架。这项研究源于我们的机制发现，FTY 720触发肝癌细胞凋亡，促进激活ROS-PKCd信号。以下目的构成了本研究的焦点：（1）进行FTY 720的结构优化和最佳衍生物的机理验证;和（2）评估结构优化的（S）-FTY 2衍生物抑制HCC异种移植物生长的体内作用。在目的1中，FTY 720的先导优化旨在将FTY 720的免疫抑制活性与其对ROS-PKCd信号传导的影响分开。（S）-FTY 2代表这方面的先导化合物，然后将使用生物测定指导的双层策略进行结构优化，包括细胞存活测定和蛋白质印迹，以针对基于（S）-FTY 2的化合物文库进行筛选，以产生有效的PKCd靶向剂。在目标2中，将在原位和异位异种移植肿瘤模型中检查最佳衍生物抑制HCC肿瘤生长的体内功效。我们期望所提出的研究产生支持我们的假设的数据，即通过小分子试剂靶向ROS-PKCd信号传导代表治疗HCC的治疗相关方法，并最终导致将改善HCC治疗并增加HCC患者存活率的新方法。公共卫生相关性：肝细胞癌（HCC）是世界范围内的主要死亡原因，在美国的患病率正在迅速增加。我们的总体研究目标是开发新的治疗药物，靶向HCC细胞中的分子和细胞缺陷，使这种疾病的临床管理具有挑战性。我们预计，该项目将最终产生新的药物，将改善肝癌的治疗和增加肝癌患者的生存。

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.