NMR studies of the lipid metabolism of T47D human breast cancer spheroids.

The in vivo 31P NMR spectrum of T47D human breast cancer cells grown as spheroids shows changes in the phosphomonoester lipid precursors as a function of spheroid size. The ratio of phosphorylethanolamine (PE) to phosphorylcholine (PC) was 1.0 +/- 0.3 for 3-day-old, 150 microns spheroids. This ratio increased to 2.4 +/- 0.4 for spheroids 7 days and older and which were at least 300 microns in diameter. To investigate the phosphatidylethanolamine to phosphatidylcholine (PdylE/PdylC) ratio in the membranes, chloroform/methanol extracts of spheroids were performed. The 31P spectrum of these extracts showed no change with spheroid size, namely the PdylE/PdylC ratio was 0.5 +/- 0.06 for spheroids of all ages suggesting that membrane composition is strongly regulated at the precursor level.