The biosynthesis of phosphatides in several tissue-culture cell lines

Summary HeLa (S3 clone) cells, bovine lymphosarcoma cells, monkey heart cells, and chick embryo endothelium cells were grown on Hanks' balanced Salt Solution supplemented with lactalbumin hydrolysate and bovine serum plus H32PO4 =. The various cell lines were labeled with inorganic 32P for varying periods of time. The phosphatides were extracted and deacylated with 0.1 N methanolic KOH at 37°C for 15 min. The deacylated phosphatides were separated by two-dimensional paper chromatography. The total phosphatide relative activity (cpm/wt protein/μg 32P applied) was determined at various times. The percent of the total phosphatide activity with time for each phosphatide was also determined. The phosphatide relative activity-time relationships demonstrated that each of the four cell lines studied varied in their phosphatide relative activities. This determination allows identification of these cell lines grown in culture. The ratio of relative activities of 32P-phosphatides to 32P-organic compounds indicated that phosphorus was utilized in the HeLa cell line preferentially for the synthesis of phosphorus compounds other than phosphatides. These other phosphorus compounds may be nucleic acids. Determinations of the per cent of total phosphatide activity for individual phosphatides in three cell lines presented evidence of a common biosynthetic pathway for phosphatides. Biosynthetic interrelationships of phosphatides were postulated to satisfy the sequential labeling of those phosphatides in both plants and animals. It was impossible to distinguish any basic difference between malignant and normal cells in culture by the procedures employed herein.