Targeting lipid metabolic and signaling enzyme in ovarian cancer

描述（申请人提供）：卵巢癌是西方国家妇科疾病中导致死亡的主要原因。确定重要的肿瘤生物标志物和关键的致病途径对卵巢癌的预后和治疗策略至关重要。导致卵巢肿瘤发展的病因病理学途径涉及的机制是由于活性的变化而不是靶基因的表达水平。我们启动了一项基于活性的蛋白质组学分析（ABPP）研究，以确定丝氨酸水解酶超家族的全球活性状态，并发现在浆液性卵巢肿瘤中，参与醚脂质代谢信号通路的几种酶的活性升高，从而导致肿瘤生长和进展所需的溶血磷脂酸的产生。其中一种异常活跃的酶是血小板活化因子乙酰水解酶I (PAF- ah I)，它能水解血小板活化因子（PAF）。用不能被这种酶水解的PAF类似物治疗卵巢癌细胞显示出明显增强的癌细胞死亡。我们推测该酶在卵巢发病机制中发挥重要作用，靶向PAF-AH I通路可能是卵巢癌有效的预防和干预策略。本建议的具体目的是：1。利用短发夹RNA （shRNA）研究PAF-AH I酶在正常卵巢表面上皮细胞（HOSE）中的异位表达和在卵巢癌细胞系中对该酶的抑制作用，并测量细胞生长侵袭性、脂质信号和代谢物谱的变化；2. 评价选定的PAF类似物对癌细胞活力、酶活性、脂质信号和代谢物的影响；和3。研究特异性目的1和2中PAF-AH I通路的表达、活性和代谢物特征是否与卵巢肿瘤的临床病理特征（包括生存）有显著相关性。这一创新的建议整合了酶促蛋白质组及其主要生化输出（代谢组）的研究。预计对PAF-AH I通路失调控的活性和代谢物特征的鉴定和表征将对卵巢癌患者的诊断、监测、临床管理和总体结局产生重大的转化影响。

DESCRIPTION (provided by applicant): Ovarian cancer is the leading cause of death among gynecologic diseases in Western countries. Identification of significant tumor biomarkers and key pathogenic pathways is of paramount importance for ovarian cancer prognosis and treatment strategies. The etiopathologic pathways leading to the development of ovarian tumors involve mechanisms that are due to changes in activity rather than expression level of the target genes. We have initiated an activity-based proteomic profiling (ABPP) study to determine global activity status of serine hydrolase superfamily and found that in serous ovarian tumors there are elevated activities of several enzymes involved in an ether lipid metabolic signaling pathway, which results in the production of lysophosphatidic acids for tumor growth and progression. One such aberrantly active enzyme is platelet-activating factor acetylhydrolase I (PAF-AH I), which hydrolyzes platelet-activating factor (PAF). Treatments of ovarian cancer cells with PAF analogues that are non-hydrolysable by this enzyme showed significantly enhanced cancer cell death. We hypothesize that this enzyme plays a significant role in ovarian pathogenesis and targeting the PAF-AH I pathway may constitute an effective preventive and intervention strategy for ovarian cancer. The specific aims of this proposal are: 1. To delineate the role of PAF-AH I enzyme in ovarian pathogenesis by ectopic expression in normal human ovarian surface epithelial (HOSE) cells and inhibition of the enzyme in ovarian cancer cell lines using short hairpin RNA (shRNA), and measure any changes in cell growth invasiveness, lipid signaling and metabolite profile; 2. To evaluate the effects of selected PAF analogues on cancer cell viability, enzyme activity, lipid signaling and metabolites; and 3. To investigate if the expression, activity, and metabolite signatures of PAF-AH I pathway identified in Specific Aims One and Two have any significant correlations with clinicopathologic characteristics including survival of ovarian tumors. This innovative proposal integrates the studies of both the enzymatic proteome and its primary biochemical output (the metabolome). It is expected that identification and characterization of activity and metabolite signatures of the deregulated PAF-AH I pathway will have significant translational impact on diagnosis, surveillance, clinical management and overall outcome of ovarian cancer patients. PUBLIC HEALTH RELEVANCE: This project is focused on the studies of enzymatic activity and metabolomic signatures of an enzyme in a novel ether lipid metabolic and signaling pathway that is deregulated in ovarian cancer. Ether lipid analogues that are not hydrolysable by this enzyme have shown significant efficacies in killing cancer cells. Hence, our proposed study will have significant impacts on the prevention, clinical management, and treatment strategies of ovarian cancer patients.