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Rhodamine 123 inhibits protein synthesis in mitochondria isolated from normal and cancer tissues

Conference · · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)
OSTI ID:5230441

The dye rhodamine 123 (Rho 123) is well known to specifically stain mitochrondria in living cells. Its accumulation in these organelles is associated with certain toxic effects where the dye is found to inhibit bioenergetic function in normal and cancer mitochondria. Since mitochondria appear to be a target for Rho 123 interaction, the authors investigated its effects on mitochondrial protein synthesis (PS) in rat liver, and in both erythroleukemia and chloroleukemia tumors. L-(/sup 14/C) leucine incorporation into mitochondria protein was used to determine the rate of PS. While the specific activity of leucine incorporation was much higher in tumor as compared to liver mitochondria, the addition of 10 ..mu..g Rho 123/ml in all tested mitochondria resulted in 75-80% inhibition. Similar results were obtained with 10 ..mu..g/ml of chloramphenicol, the specific inhibitor for mitochondrial PS. PS inhibition in the three types of mitochondria was Rho 123 concentration-dependent being about 50% at 5 ..mu..g/ml and with total inhibition at 15-20 ..mu..g/ml. Moreover, the addition of Rho 123 to mitochondria under PS condition did not trigger any ATPase activity. If present, such activity would compete for ATP which is the energy source of PS. These results demonstrate that the mitochondrial probe Rho 123 has a potent inhibitory effect on PS in both normal and cancer mitochondria.

Research Organization:
Univ. of Miami School of Medicine, FL
OSTI ID:
5230441
Report Number(s):
CONF-8606151-
Journal Information:
Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:6; ISSN FEPRA
Country of Publication:
United States
Language:
English