Chen J K, Okamoto T, Sato J D, Sato G H, McClure D B
Exp Cell Res. 1986 Mar;163(1):117-26. doi: 10.1016/0014-4827(86)90563-x.
The biochemical basis for the cholesterol-dependent growth phenotype of the NS-1 myeloma cell line has been investigated. In one series of experiments, the growth response of NS-1 cells to several of the intermediates of cholesterol biosynthesis was studied in serum-free medium. The cholesterol precursors, squalene and lanosterol, were totally ineffective in promoting NS-1 cell growth. In contrast, cholesterol precursors downstream from lanosterol, i.e., desmosterol and 7-dehydrocholesterol, completely replaced cholesterol in supporting NS-1 cell growth. In a second series of experiments, NS-1 cells and NS-1-503 cells (a cholesterol growth-independent variant of NS-1 cells) were labelled with [2-14C]acetate and the distributions of radioactivity between cholesterol and its precursors were determined by thin-layer chromatography using two different solvent systems. The major labelled sterol product (greater than 80%) in NS-1 cells after a 24-h exposure to [2-14C]acetate was lanosterol. In contrast, the major labelled sterol product (greater than 95%) in NS-1-503 cells after a 24-h exposure to [2-14C]acetate was cholesterol. Taken together, these results indicate that NS-1 cells are defective in cholesterol biosynthesis and identify the site of lesion as the demethylation of lanosterol to C-29 sterol intermediates.
已对NS-1骨髓瘤细胞系胆固醇依赖性生长表型的生化基础进行了研究。在一系列实验中，在无血清培养基中研究了NS-1细胞对几种胆固醇生物合成中间体的生长反应。胆固醇前体角鲨烯和羊毛甾醇在促进NS-1细胞生长方面完全无效。相比之下，羊毛甾醇下游的胆固醇前体，即去氢胆甾醇和7-脱氢胆固醇，在支持NS-1细胞生长方面完全可以替代胆固醇。在第二系列实验中，用[2-¹⁴C]乙酸盐标记NS-1细胞和NS-1-503细胞（NS-1细胞的一种不依赖胆固醇生长的变体），并使用两种不同的溶剂系统通过薄层色谱法测定胆固醇及其前体之间的放射性分布。在暴露于[2-¹⁴C]乙酸盐24小时后，NS-1细胞中主要的标记甾醇产物（大于80%）是羊毛甾醇。相比之下，在暴露于[2-¹⁴C]乙酸盐24小时后，NS-1-503细胞中主要的标记甾醇产物（大于95%）是胆固醇。综上所述，这些结果表明NS-1细胞在胆固醇生物合成方面存在缺陷，并确定病变部位为羊毛甾醇向C-29甾醇中间体的去甲基化过程。
