Characterisation of 3-[I-123]iodo-L-alpha-methyl tyrosine ([I-123]IMT) transport into human Ewing's sarcoma cells in vitro

3-[I-123]Iodo-L-alpha -methyl tyrosine ([I-123]IMT) scintigraphy of extracr anial malignant tumors has been described, but Little is known about the tr ansport systems involved in [I-123]IMT uptake into extracranial tumor cells . Here, the precise kinetics of [I-123]IMT transport into human Ewing's sar coma cells (VH-64) was determined. The apparent Michaelis constant was of h igh affinity value (K-m = 41.7 +/- 3.9 muM) and maximum transport velocitiy amounted to V-max = 20.7 +/- 0.6 nmol . mg protein(-1) .10 min(-1). Inhibi tion experiments revealed the predominance of [I-123]IMT uptake via sodium- independent system L. (C) 2001 Elsevier Science Inc. All rights reserved.