In vitro studies on the cellular uptake of melanoma imaging aminoalkyl-iodobenzamide derivatives (ABA)

Abstract

The cellular uptake of 11 radioiodinated aminoalkyl-iodobenzamides (ABA) was studied using cultivated murine melanoma cells (B16/C3). All derivatives showed a high uptake (up to about 80%) of radioactivity in melanotic melanoma cells; hence, accumulation of all compounds radioiodinated in the ortho position was reduced by approximately 30%. Using the compound para-[ 131I]iododiethyl-aminoethylbenzamide ( p- 131I-ABA-2-2) a close correlation of the cellular melanin content with the tracer uptake ( R 2 = 0.95) was verified. The presence of extracellular melanin, however, had no effect on the cellular tracer uptake. Because the accumulation was independent of the specific activity of p- 131I-ABA-2-2, a significant contribution to the uptake process by binding to receptor sites could be excluded.