Targeting lipid metabolic and signaling enzyme in ovarian cancer

描述（由申请人提供）：卵巢癌是西方国家妇科疾病中的主要死亡原因。识别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。导致卵巢肿瘤发生的病因病理学途径涉及靶基因活性而非表达水平变化的机制。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整体活性状态，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，这导致溶血磷脂酸的产生，促进肿瘤的生长和进展。一种这样的异常活性酶是血小板活化因子乙酰水解酶I（PAF-AH I），其水解血小板活化因子（PAF）。卵巢癌细胞与PAF类似物的治疗是不可水解的这种酶显示显着增强癌细胞死亡。我们假设这种酶在卵巢发病机制中起重要作用，靶向PAF-AH I通路可能构成卵巢癌的有效预防和干预策略。该提案的具体目标是：1.通过在正常人卵巢表面上皮（HOSE）细胞中异位表达PAF-AH I酶和使用短发夹RNA（shRNA）抑制卵巢癌细胞系中的PAF-AH I酶来描述PAF-AH I酶在卵巢发病机制中的作用，并测量细胞生长侵袭性、脂质信号传导和代谢产物谱的任何变化; 1.评估所选PAF类似物对癌细胞活力、酶活性、脂质信号传导和代谢物的影响;以及3.研究特定目标1和2中鉴定的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（包括生存期）有任何显著相关性。这一创新的建议整合了酶蛋白质组及其主要生化输出（代谢组）的研究。预期去调节的PAF-AH I途径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、临床管理和总体结果具有显著的转化影响。 公共卫生相关性：该项目的重点是研究卵巢癌中去调节的新型醚脂代谢和信号通路中酶的酶活性和代谢组学特征。不能被这种酶水解的醚脂质类似物在杀死癌细胞方面显示出显著的功效。因此，我们提出的研究将对卵巢癌患者的预防，临床管理和治疗策略产生重大影响。

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.