Phorbol esters stimulate the rapid release of choline from prelabelled cells.
Phorbol esters stimulate the rapid release of choline from prelabelled cells.
复制标题
佛波酯刺激预先标记的细胞快速释放胆碱。
DOI：
10.1093/carcin/2.11.1095
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发表时间：
1981
期刊：
影响因子：
4.7
通讯作者：
Weinstein,IB
中科院分区：
文献类型：
--
作者：
Mufson,RA;Okin,E;Weinstein,IB
有证据表明，细胞表面膜是磷脂酯肿瘤启动子的主要作用部位，这使我们能够描述磷脂代谢的早期变化，这些变化是对这些化合物的反应。当C3H10T½小鼠胚胎成纤维细胞与[3H]胆碱孵育24 h时，约78%的细胞相关物质为磷脂酰胆碱，其余为鞘磷脂和酸溶池。将这些预先标记的细胞暴露于有效的肿瘤启动子12- o -十四烷醇-13-乙酸酯（PPD） 5分钟内，细胞向培养基中释放的水溶性[3H]代谢物增加了2倍，到60-120分钟时，释放量是对照培养中的2-5倍。经层析鉴定，释放物为胆碱和磷酰胆碱。证据表明，该物质并非完全来源于酸溶池或标记鞘磷脂的降解。胆碱代谢物释放在10 - 8 - 10 - 7M TPA之间呈浓度依赖性，与细胞毒性无关。phorpol -12,13-didecanoate （PDD）也有活性，而非肿瘤启动子的4αPDD则无活性。环己胺（4-40 μg/ml）和冬虫夏草素（4-40 μg/ml）均未阻断TPA诱导的释放。然而，释放对温度敏感，在4°C时不发生。TPA不诱导预标记的磷脂酰肌醇释放[3H]肌醇。钙离子载体A23187诱导预标记细胞释放花生四烯酸，但不诱导胆碱释放。此外，抑制脂氧合酶和环氧合酶活性的5,8,11,14-二十碳四烯酸并未抑制TPA刺激胆碱释放。我们提出TPA与细胞表面受体的结合导致膜相关磷脂酶的快速激活，该酶特异性地降解磷脂酰胆碱。这种作用可能类似于其他激动剂激活磷脂酰肌醇降解的能力。
Evidence implicating the cell surface membrane as the primary site of action of phorbol ester tumor promoters has led us to characterize early changes in phospholipid metabolism which occur in response to these compounds. When C3H10T½ mouse embryo fibroblasts were incubated with [3H]choline for 24 h, ˜78% of the cell associated material was found in phosphatidyl choline and the remainder in sphingomyelin and the acid soluble pool. Within 5 min of exposure of these prelabelled cells to the potent tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate (PPD) the release of water soluble [3H] metabolites from cells into the medium was enhanced 2-fold and by 60–120 min the release was 2–5 times that found in control cultures. The released material was identified by chromatography as choline and phosphoryl choline. Evidence was obtained that this material was not derived exclusively from the acid soluble pool or from the degradation of labelled sphingomyelin. Choline metabolite release was concentration dependent between 10−8and 10−7M TPA and was not associated with cell toxicity. Phorbol-12,13-didecanoate (PDD) was also active but 4αPDD, which is not a tumor promoter, was inactive. Neither cyclohexlmide (4–40 μg/ml) nor cordycepln (4–40 μg/ml) blocked the TPA induced release. The release was, however, temperature sensitive and did not occur at 4°C. TPA did not induce the release of [3H]inositol from prelabelled phosphatidyl inositol. Although, the calcium ionophore A23187 induced the release of arachidonic acid from prelabelled cells it did not induce choline release. In addition, 5,8,11,14-eicosatetraynoic acid, which inhibits both lipoxygenase and cyclooxygenase activity, did not inhibit TPA stimulation of choline release. We propose that the binding of TPA to cell surface receptors leads to a rapid activation of membrane associated phospholipase(s) that specifically degrade phosphatidyl choline. This effect may be analogous to the ability of other agonists to activate degradation of phosphatidyl inositol.