Mannose toxicity in Ehrlich ascites tumor cells.
Mannosephosphate isomerase (MPI) showed a higher activity than hexokinase (HKM) in its ability to phosphorylate mannose in the spleen, thymus, brain, liver, striated muscles, kidneys, and testes from BALB/c mice. This led to a HKM/MPI ratio of less than 1 in all the organs and tissues mentioned. In contrast, Ehrlich ascites tumor cells obtained from the peritoneum of BALB/c mice had low MPI activity (half of the HKM activity and, therefore, a ratio of 2). Mannose, which is nontoxic to nontumor cells at a concentration of 0.1 M, induced marked in vitro mortality of the tumor cells. Incubation of Ehrlich ascites tumor cells with mannose resulted in a high accumulation of mannose-6-phosphate and a marked depletion of ATP which did not appear when the cells were incubated with glucose. These facts may explain the selective mortality caused by mannose in the tumor cells studied.
Department of Animal Biology II (Animal Physiology), Faculty of Biological Science, Complutense University, Madrid, Spain.
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De la Fuente
D000818:Animals; D002286:Carcinoma, Ehrlich Tumor / Q000378:metabolism* / Q000473:pathology; D002470:Cell Survival / Q000187:drug effects; D008297:Male; D008358:Mannose / Q000633:toxicity*; D051379:Mice; D008807:Mice, Inbred BALB C; D009928:Organ Specificity; D010766:Phosphorylation
D008358:Mannose