Biochemical characterization of the cholesterol-dependent growth of the NS-1 mouse myeloma cell line.
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.
D000085:Acetates / Q000378:metabolism; D000818:Animals; D002455:Cell Division; D002460:Cell Line; D002784:Cholesterol / Q000096:biosynthesis* / Q000494:pharmacology; D003470:Culture Media; D003684:Dehydrocholesterols / Q000494:pharmacology; D003897:Desmosterol / Q000494:pharmacology; D007810:Lanosterol / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D051379:Mice; D009101:Multiple Myeloma / Q000378:metabolism* / Q000473:pathology; D010641:Phenotype; D013185:Squalene / Q000494:pharmacology; D013261:Sterols / Q000378:metabolism
D000085:Acetates; D003470:Culture Media; D003684:Dehydrocholesterols; D013261:Sterols; D007810:Lanosterol; D003897:Desmosterol; C015316:lanostenol; D013185:Squalene; D002784:Cholesterol; C016705:7-dehydrocholesterol; C015582:zymosterol