Effect of methionine-deprived nutrition on cell growth and cell kinetics in cell cultures and experimental tumors.

The effect of methionine-deprived nutrition on cell growth and cell kinetics was investigated in cell cultures and in tumor-bearing rats using the total parenteral nutrition (TPN) technique. A simultaneous flow cytometric measurement of the cellular DNA content and the amount of 5-bromodeoxyuridine incorporated into cellular DNA was performed for analysis of cell kinetics. The methionine-free medium demonstrated a cytocidal effect on the growth of SLC cells after 6 hours of culturing. It decreased viability from 80% in the control medium to 23%, and it decreased the S phase and increased the G0/G1 phase of the cell cycles. The methionine-deprived medium showed a concentration-dependent inhibition in cellular growth. Methionine-deprived TPN was seen to inhibit AH109A and SLC tumor growth compared with conventional TPN and decreased the S phase and increased the G0/G1 phase of cell cycles. These results confirm that methionine deprivation blocks cells from processing into the G1 phase and recycling, and that it is effective in inhibiting tumor growth in cultures and in vivo.