Antibody to lactate dehydrogenase II. Inhibition of glycolysis and growth of tumor cells

Abstract

1. 1. The effect of antibody to lactate dehydrogenase ( L-lactate:NAD + oxidoreductase, EC 1.1.1.27) on the glycolysis and growth in vitro of rabbit Vx-2 tumor cells, mouse Ehrlich carcinoma cells, and embryonic rabbit kidney and skeletal muscle cells were studied. 2. 2. During 90-min Warburg respirometer studies, antibody to rabbit lactate dehydrogenase (anti-lactate dehydrogenase) caused no significant inhibition of anaerobic glycolysis by intact rabbit Vx–2 tumor cells but inhibited 19% of their aerobic glycolysis. Antibody to mouse lactate dehydrogenase caused no inhibition of either aerobic or anaerobic glycolysis of Ehrlich cells during this time. Sodium oxamate (3.10 −2 M), a competitive inhibitor of lactase dehydrogenase, inhibited anaerobic glycolysis of Ehrlich cells by 51% and aerobic glycolysis by 71–100%. 3. 3. With Vx–2 tumor cells growing in vitro both anti-lactate dehydrogenase and sodium examate significantly inhibited lactic acid formation and glucose uptake from the earliest time intervals (10 h) tested and almost totally inhibited tumor cells reproduction. 4. 4. With Ehrlich carcinoma cells growing In vitro sodium oxamate inhibited glycolysis by 10 h or sooner and anti-lactate dehydrogenase inhibited glycolysis after a 24-h lag. Both agents inhibited cell reproduction. 5. 5. Rates of lactic acid formation and protein synthesis by non-malignant embryonic rabbit kidney and muscle cells growing in vitro were not affected by antilactate dehydrogenase. Sodium oxamate partially inhibited glycolysis and protein synthesis by these cells.