In vitro and in vivo 31P nuclear magnetic resonance measurements of metabolic changes post radiation.

TitleIn vitro and in vivo 31P nuclear magnetic resonance measurements of metabolic changes post radiation.
Publication TypeJournal Article
Year of Publication1995
AuthorsMahmood U, Alfieri AA, Ballon D, Traganos F, Koutcher JA
JournalCancer Res
Volume55
Issue6
Pagination1248-54
Date Published1995 Mar 15
ISSN0008-5472
KeywordsAnimals, Cell Cycle, Deoxyuracil Nucleotides, Energy Metabolism, Magnetic Resonance Spectroscopy, Male, Membrane Lipids, Mice, Mice, Inbred C3H, Neoplasms, Experimental, Phosphates, Phosphocreatine, Phospholipids
Abstract

Radiation-induced metabolic changes previously observed in tumors using phosphorus nuclear magnetic resonance spectroscopy include changes in the relative amounts of the phospholipid precursors phosphoethanolamine and phosphocholine, increases in membrane catabolites, and increases in energy status. To elucidate the degree to which these in vivo alterations are a result of intrinsic cellular changes versus radiation-induced systemic effects, the Radiation-Induced Fibrosarcoma-1 tumor model was studied before and over the course of 7 days after a single dose of 17 Gy. In vivo studies were performed with tumors implanted in C3H/He mice; in vitro studies used cells that were perfused in agarose gel threads after being grown, radiated, and maintained in monolayer. The statistically significant increases in the downfield component of the phosphomonoester peak, which consists primarily of phosphoethanolamine, compared to the upfield component, phosphocholine, were qualitatively similar in vivo and in vitro post radiation. Statistically significant increases in the membrane catabolite glycerophosphocholine, a phosphodiester, were also observed in both tumors and cell culture after irradiation, with a greater percentage change in vitro. This suggests that changes in the phosphomonoester and phosphodiester concentrations are primarily an intrinsic effect of radiation on cellular metabolism, modulated to a lesser degree by systemic effects. In contrast, the statistically significant increases in energy status after the 17-Gy dose showed markedly different temporal responses in the two systems. Therefore, energy status changes observed in vivo are due largely to systemic changes, such as changes in blood flow. Flow cytometry data obtained from the cultured cells showed a sustained increase in the G2-M fraction starting at 24 h, the first time point measured after irradiation, which continued for the 7 days studied post radiation. These data indicate that the in vivo changes detected by nuclear magnetic resonance in phospholipid precursors and catabolites occur directly at the cellular level and may reflect cell death or growth inhibition after antineoplastic therapy.

Alternate JournalCancer Res
PubMed ID7882317
Grant List5 PO1 CA 25842-14 / CA / NCI NIH HHS / United States
CA 28704 / CA / NCI NIH HHS / United States
Related Institute: 
MRI Research Institute (MRIRI)

Weill Cornell Medicine
Department of Radiology
525 East 68th Street New York, NY 10065