Glycolytic inhibitor, 2-deoxy-D-glucose, does not enhance radiation-induced apoptosis in mouse thymocytes and splenocytes in vitro.
Earlier studies have shown that 2-deoxy-D-glucose (2-DG), a glucose analogue and inhibitor of glycolytic ATP production selectively enhances radiation-induced damage in cancer cells by inhibiting the energy (ATP) dependent postirradiation DNA and cellular repair processes. A reduction in radiation induced cytogenetic damage has been reported in normal cells viz., peripheral blood lymphocytes and bone marrow cells. Since induction of apoptosis plays a major role in determining the radiosensitivity of some most sensitive normal cells including splenocytes and thymocytes, we investigated the effects of 2-DG on radiation induced apo tosis in these cells in vitro. Thymocytes and splenocytes isolated from normal Swiss albino mouse were irradiated with Co60 gamma-rays and analyzed for apoptosis at various post-irradiation times. 2-DG added at the time of irradiation was present till the termination of cultures. A time dependent, spontaneous apoptosis was evident in both the cell systems, with nearly 40% of the cells undergoing apoptosis at 12 hr of incubation. The dose response of radiation-induced apoptosis was essentially similar in both the cell systems and was dependent on the incubation time. More than 70% of the splenocytes and 60% of the thymocytes were apoptotic by 12 hr following an absorbed dose of 2 Gy. Presence of 2-DG marginally reduced the fraction of splenocytes undergoing apoptosis at all absorbed doses, while no change was observed in thymocytes. Presence of 2-DG did not significantly alter either the level or the rate of induction of spontaneous apoptosis in both these cell systems. These results are consistent with the earlier findings on radiation-induced cytogenetic damage in human PBL in vitro and mouse bone marrow cells and lend further support to the proposition that 2-DG does not enhance radiation damage in normal cells, while radiosensitizing the tumors and hence is an ideal adjuvant in the radiotherapy of tumors.
Swamy
R K
RK
Institute of Nuclear Medicine and Allied Sciences, Delhi 110 054.
Manickam
J
J
Adhikari
J S
JS
Dwarakanath
B S
BS
D000818:Animals; D000963:Antimetabolites / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D003847:Deoxyglucose / Q000494:pharmacology*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005720:Gamma Rays; D051379:Mice; D013154:Spleen / Q000166:cytology* / Q000187:drug effects / Q000528:radiation effects; D013950:Thymus Gland / Q000166:cytology* / Q000187:drug effects / Q000528:radiation effects
D000963:Antimetabolites; D004247:DNA; D003847:Deoxyglucose