Effects of Hyperthermia and L-Ascorbic Acid on Glucose, Pyruvate, and Lactate Metabolism in Ehrlich Ascites Carcinoma Cells

Abstract

After several years of intense interest in technique has been described (7,9). Labeled hyperthermia as a potential treatment for [ U-'4C]glucose (NEC-042) and [ 1-l4C]pyrucancer, little is known about the mechanisms vate (NEC-255) were obtained from New of heat-dependent tumor cell destruction. En-England Nuclear (Boston, Mass.). The convironmental or extracellular factors, particu-centration of ascorbic acid in the flasks was larly nutritional state and degree of oxygen-either 0 or 1 mM. A proportional temperature ation, have been shown to influence the sus-controller (Yellow Springs Instruments ceptibility of tumor cells to destruction by Model 72) was used to precisely control hyperthermic treatment (1-3). Overgaard has shaker bath water temperature (+O. 1 "). postulated that hyperthermia inhibits respi-Following the incubation period, the reacration, but not glycolysis, resulting in in-tions were stopped by injecting 1 ml of 2 N creased lactate levels and a decreased pH (4, HC104 through the serum caps. The flasks 5). An increase in cellular acidity has been were then shaken an additional hour to reshown to enhance hyperthermic lethality (6). cover l4COn. Blanks were prepared by adding This communication examines the effect of PCA before addition of the cell suspension. hyperthermia on glucose, pyruvate, and lac-After shaking with PCA, the paper and vial tate metabolism in Ehrlich ascites tumor cells were removed and placed in a scintillation (EATC). The role of ascorbic acid, which has vial containing 15 ml of cocktail (7) before been shown to greatly increase respiration in counting in a Packard Tri-Carb scintillation EATC suspensions (7) was also examined.spectrometer. Quench correction was done Materials and methods. EATC were serially using the channels ratio method. transplanted intraperitoneally at regular in-All in vitro tumor cell experiments were in tervals in male Swiss mice.2 Cells were har-the presence of glucose as the substrate. Colvested 6-14 days after transplantation. The orimetric analysis of lactic acid was perprotein content was determined by a biuret formed enzymatically with a Gilford 240 digmethod using bovine serum albumin as the ital spectrometer (10). standard (8). Experimental hyperthermia and EATC metabolism of [ 1 -14C]pyruvate with the effect of supplemental ascorbic acid were supplemental combinations of ascorbic acid examined simultaneously.(1 mM), theophylline (1 mM), and dibutyryl Metabolic studies were performed in 25-ml cyclic AMP (1 mM) was studied in vitro at stoppered siliconized glass Erlenmeyer flasks 37.5" and 42.5". These experiments were conwith specially constructed center wells for ducted to study whether ascorbic acid may COn collection. All incubations were per-alter metabolism by potentiating intracellular formed in Krebs Ringers phosphate buffer CAMP levels. without calcium (1 8). The 14C02 collection In a separate preliminary study the effect of dietary supplementation of 5% ascorbate This work was supported by grants from the Keating on tumor cell metabolis...

Substrate utilization for lactate and energy production by heat‐shocked L929 cells

“…Thus, lactate production was markedly increased while TCA cycle glutamine flux was somewhat increased. Lactate production during heat shock has been observed before and attributed to increased glycolysis (Piontek et al, 1979;Burdon et al, 1984) or to hypoxia (Hammond et al, 1982). However, the effect of heat shock cannot be primarily on glycolysis since most of the lactate produced by L929 cells is derived from exogenous pyruvate and oxygen consumption could be further increased by dinitrophenol.…”

The role of energy in hyperthermia‐induced mammalian cell inactivation: A study of the effects of glucose starvation and an uncoupler of oxidative phosphorylation

“…Another possibility is that the starvation period (without CCP) is long enough to permit the development of thermotolerance (Li and Hahn, 1980). A cell in the thermotolerant state may use its energy in a more economical way, Experiments by Piontek et al (1979) do not show an altered glucose metabolism due to hyperthermia (1 hr, 42.5"C). Nevertheless, glucose analogs have been shown to potentiate effects of hyperthermia (Kim et al, 1978b), especially under hypoxic conditions (Song et al, 1979).…”

Energetics of Dna Repair: Effects of Temperature on Dna Repair in Uv‐irradiated Peripheral Blood Leucocytes From Chronic Myeloid Leukemic Patients*

“…The results on thermal effects on energy metabolism of CML leucocytes in the presence of 2DG+AA indicate that the extent of inhibition in lactate production and glucose uptake does not alter significantly with temperature in the range of 3443°C for 2 h post irradiation incubation (Table 2). Experiments by Piontek et al (1979) also do not show an altered glucose metabolism due to hyperthermia (42.5"C) of short duration up to 2 h in Ehrlich ascites tumor cells. There are conflicting reports on the effect -of temperature on depletion of intracellular ATP levels and role of glycolysis and oxidative phosphorylation due to differences in the thermal sensitivity of different cell systems, culture conditions and conditions of heating (Cavaliere et al, 1967;Hahn, 1974;Gerweck et al, 1979;Haveman and Hahn, 1981).…”