Liscum L, Collins G J
Department of Physiology, Tufts University School of Medicine, Boston, Massachusetts 02111.
J Biol Chem. 1991 Sep 5;266(25):16599-606.
The pharmacological agent U18666A (3-beta-[2-(diethylamino)ethoxy]androst-5-en-17-one inhibits the intracellular transport of low density lipoprotein (LDL)-derived cholesterol in Chinese hamster ovary (CHO) cells. LDL-derived cholesterol accumulates in the lysosomes of U18666A-treated cells causing delayed LDL-mediated regulation of cellular cholesterol metabolism and impaired movement of LDL-derived cholesterol to other cell membranes. As a result of impaired LDL-derived cholesterol transport, LDL-dependent growth of CHO cells is also inhibited by U18666A. By selecting for cell growth in the presence of U18666A, we have identified a CHO cell line, designated U18R, that is resistant to U18666A-inhibition of LDL-derived cholesterol trafficking. When compared to parental CHO cells, U18R cells are relatively resistant to U18666A inhibition of LDL-derived cholesterol transport as well as LDL-mediated regulation of cellular cholesterol metabolism. In cell fusion experiments, the U18666A resistance observed in U18R cells displays a dominant phenotype. Identification of the U18666A-resistant factor may provide important insights toward the understanding of intracellular LDL-derived cholesterol regulation and trafficking.
药理剂U18666A（3-β-[2-（二乙氨基）乙氧基]雄甾-5-烯-17-酮）抑制中国仓鼠卵巢（CHO）细胞中低密度脂蛋白（LDL）衍生胆固醇的细胞内转运。LDL衍生的胆固醇积聚在经U18666A处理的细胞的溶酶体中，导致LDL介导的细胞胆固醇代谢调节延迟，以及LDL衍生的胆固醇向其他细胞膜的移动受损。由于LDL衍生的胆固醇转运受损，U18666A也抑制了CHO细胞依赖LDL的生长。通过在U18666A存在下选择细胞生长，我们鉴定出一种CHO细胞系，命名为U18R，它对U18666A抑制LDL衍生的胆固醇运输具有抗性。与亲代CHO细胞相比，U18R细胞对U18666A抑制LDL衍生的胆固醇运输以及LDL介导的细胞胆固醇代谢调节具有相对抗性。在细胞融合实验中，在U18R细胞中观察到的U18666A抗性表现出显性表型。鉴定U18666A抗性因子可能为理解细胞内LDL衍生的胆固醇调节和运输提供重要见解。
