Marignancy of cell-proliferative diseases by unusual production of phospholipid mediators in response to oxidative stress

首先，我们设计了一种有用的定量方法来测定过氧化磷脂酰胆碱（PC）的初级（氢过氧化物）和次级[血小板活化因子（PAF）样脂质]产物。通过这些方法，我们发现在人血浆中Cu^+[含二羧酸酯(DC)- PC >二羧酸半醛(DCsa)-含PC >单羧酸酯(MC)- PC]的培养过程中产生了三种具有短链酰基的paf样脂质。与Fe^<2+>孵育的人血浆中主要的paf样脂质是MC-PC。检测到少量的DCsa-PC，但未检测到DC-PC。在浓度低于25 μM时，DC-PC和DCsa-PC均能促进人脐静脉内皮细胞的增殖，而在浓度较高时，则能诱导内皮细胞凋亡。我们发现，从人血浆中部分纯化的溶血磷脂酶D （lysoPLD）和重组的溶血磷脂酶/autotaxin可水解paf样脂质及其去酰化产物（溶血磷脂酰胆碱），生成具有短链酰基的磷脂酸和对多种动物细胞具有强大细胞增殖作用的溶血磷脂酸。我们设计了一种在微孔板阅读器上测定溶酶pld活性的简便方法。我们发现，子痫前期和早产患者血清中溶酶pld活性高于正常妊娠妇女，卵巢癌、囊腺瘤、皮样囊肿和子宫肌瘤患者腹膜液中溶酶pld活性高于其他妇科疾病患者。根据这些结果，我们认为动物体内氧化应激的增加导致生物膜和脂蛋白中的PC过氧化，随后C-C键断裂，产生paf样脂质。paf样脂质及其去乙酰化产物在各种生物体液中被溶磷脂活性水解为生物活性磷脂酸和溶血磷脂酸。本研究结果提示，子痫前期血管内皮损伤患者和妇科肿瘤患者的生物液中溶酶pld的高活性可能是影响其恶性程度的一个因素

First, we devised useful quantitative methods for primary (hydroperoxides) and secondary [platelet-activating factor (PAF)-like lipid] products of peroxidized phosphatidylcholines (PC). Using these methods, we found that three PAF-like lipids having a short chain acyl group were generated during incubation of human plasma with Cu^+ [dicarboxylate(DC)-containing PC > dicarboxylate semialdehyde(DCsa)-containing PC > monocarboxylate(MC)-containing PC]. The predominant PAF-like lipid in human plasma incubated with Fe^<2+> was MC-PC. A minor amount of DCsa-PC, but not DC-PC, was also detected. Both DC-PC and DCsa-PC stimulated the proliferation of human umbilical vein endothelial cells at concentrations less than 25 μM, but induced the apoptosis of the endothelial cells at higher concentrations.We found that lysophospholipase D (lysoPLD) partially purified from human plasma and recombinant lysoPLD/autotaxin hydrolyzed PAF-like lipids and their deacylated product (lysophosphatidylcholine) in … More to phosphatidic acid having a short chain acyl group and lysophosphatidic acid that possess a potent cell-proliferative effect on various animal cells.We devised a convenient assay for lysoPLD activity on a microplate reader. With use of the assay, we found that lysoPLD activities in sera from patients suffering from preeclamptia and preterm labor were higher than that observed for women under normal pregnancy, We also found that lysoPLD activities in peritoneal fluids from patients with ovarian cancer, cystadenoma, dermoid cyst and myoma uteri were higher than those for patients with other gynecological disease.From these results, we suggested that increased oxidative stress in animal body caused peroxidation of PC in biomembranes and lipoproteins followed by the cleavage of C-C bond(s), generating PAF-like lipid. The PAF-like lipids and their deacylated product were then hydrolyzed by lysoPLD activity in various biological fluids into bioactive phosphatidic acid and lysophosphatidic acid. Our results indicate that high lysoPLD activity in the biological fluids from preeclamptic patients with injured vascular endothelium and patients with gynecological tumor might be a factor that could affect the malignancy of the diseases Less