High-frequency 1H NMR studies of the effects of growth factors and phorbol esters on normal Syrian hamster diploid fibroblast cells.

The nuclear magnetic resonance (NMR) parameters, spin-lattice (T1), and spin-spin (T2) relaxation time, are usually longer for neoplastic cells than for normal cells of the same cell type. This has generally been true at low NMR frequencies (less than or equal to 100 MHz) when comparisons have been made between normal and neoplastic cells that have both spent a short time in culture. We have previously demonstrated that although the T1 values of paired normal and neoplastic Syrian hamster (SH) fibroblastic cells in culture are not significantly different when measured at 300 MHz, the 300 MHz T2 values for the neoplastic cells are smaller than those of the normal cells. (Xin et al. (1986), Cell Biophysics 8, 213.) Since treatment of normal diploid cells with polypeptide growth factors or tumor promoters frequently results in reversible expression of neoplasia-associated phenotypes, T1 and T2 were obtained at 300 MHz for treated and untreated SH cells to see if these compounds could also produce smaller 300 MHz T2 values. Secondary culture SH fetal fibroblast cells were treated with epidermal growth factor (EGF), fibroblast growth factor (FGF), phorbol-12,13-didecanoate (PDD) and 4-alpha-phorbol-12,13-didecanoate (4 alpha PDD). Treatment with either growth factor resulted in smaller T2 values, but a statistically significant decrease was not observed for PDD or 4 alpha PDD. The observed reductions in T2 values were correlated with the morphological and growth-stimulatory effects of these compounds on the cells.