Scandella C J, Hayward J A, Lee N
J Supramol Struct. 1979;11(4):477-83. doi: 10.1002/jss.400110406.
Polyene antibiotics such as filipin selectively inhibit wheat germ agglutinin-induced agglutination of transformed and malignant cells compared to normal cells (Hatten ME, Burger MM: Biochemistry 18: 739, 1979). Since filipin binds specifically to cholesterol, we measured cholesterol levels in 3T3 cells and SV101-3T3 cells. SV101-3T3 cells contained 50-100% more cholesterol per cell than 3T3 cells. Both cell types were starved for cholesterol by growth in lipid-depleted medium plus 25-hydroxycholesterol. The cholesterol level of SV101-3T3 cells decreased by 30-50%, while the level in 3T3 cells remained constant. Filipin-stained SV101-3T3 cells revealed bright patches of filipin under fluorescence microscopy. These patches were absent in 3T3 cells and in SV101-3T3 and 3T3 cells starved for cholesterol. We selectively labeled plasma membranes of these cells with a spin label analog of phosphatidylcholine. The spin label indicated differences in plasma membrane fluidity that may be related to the different cholesterol levels in 3T3 and SV101-3T3 cells.
与正常细胞相比，多烯抗生素（如制霉菌素）能选择性抑制麦胚凝集素诱导的转化细胞和恶性细胞的凝集（哈滕ME，伯格MM：《生物化学》18：739，1979）。由于制霉菌素能特异性结合胆固醇，我们测定了3T3细胞和SV101 - 3T3细胞中的胆固醇水平。SV101 - 3T3细胞每个细胞所含的胆固醇比3T3细胞多50 - 100%。两种细胞类型在缺乏脂质的培养基中添加25 - 羟基胆固醇进行培养，从而使胆固醇饥饿。SV101 - 3T3细胞的胆固醇水平下降了30 - 50%，而3T3细胞中的胆固醇水平保持不变。用荧光显微镜观察经制霉菌素染色的SV101 - 3T3细胞，可看到制霉菌素的明亮斑块。这些斑块在3T3细胞以及胆固醇饥饿的SV101 - 3T3细胞和3T3细胞中不存在。我们用磷脂酰胆碱的自旋标记类似物选择性标记这些细胞的质膜。自旋标记显示了质膜流动性的差异，这可能与3T3细胞和SV101 - 3T3细胞中不同的胆固醇水平有关。
