Premium
31 P NMR studies of cultured human tumor cells. Influence of ph on phospholipid metabolite levels and the detection of cytidine 5′‐diphosphate choline
Author(s) -
Kuesel A. C.,
Graschew G.,
Hull W. E.,
Lorenz W.,
Thielmann H. W.
Publication year - 1990
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.1940030206
Subject(s) - phosphocholine , phosphomonoesters , chemistry , metabolite , choline , hepes , phosphocreatine , phospholipid , cell culture , trypan blue , biochemistry , pi , microbiology and biotechnology , phosphate , in vitro , biology , phosphatidylcholine , inorganic phosphate , endocrinology , genetics , membrane , energy metabolism
202 MHz 31 P NMR (11.7 T) was used to study the effects of culture medium pH on the levels of phosphate metabolites in three human tumor cell lines (XP29MAmal, a malignant xeroderma pigmentosum; CX‐1, a colon carcinoma; KB, a squamous cell carcinoma of the oral cavity). Cells were cultured in Roux flasks in HAM's F‐12 medium, and the pH was varied with the final medium change. After harvesting, 1–5 × 10 8 cells were suspended in Ringer/HEPES buffer at pH 7.4 and 4°C for 31 P NMR studies. Cell adhesion and growth rate decreased with decreasing pH, but, down to ca pH 6.1, trypan blue exclusion and the observed levels of nucleoside di‐ and triphosphates (range: 22–37% of total phosphates detected), phosphocreatine (PCr, 2–5%) and P i (5–11%) did not vary significantly with pH. For XP29MAmal cells in exponential growth phosphocholine levels decreased from 18–28% at pH 7.0 to ca 5% at pH 6.0, while phosphoethanolamine levels increased from 2–7% to 15%. Glycerophosphocholine (GPC) levels increased from ca 7% at pH 7.2 to 13% at pH 6.3. At pH<6.3 cytidine 5′‐diphosphate (CDP) choline became detectable (8–16%, δ P : P α = −8.13 ppm, P β = 8.93 ppm, for PCr = 0 ppm). However, confluent cells did not accumulate CDP‐choline when the pH was lowered. The cell lines CX‐1 and KB also showed the pH effects described herein.