F-18 labeled ethanolamine derivatives for tumor imaging - Comparison with F-18 ethylcholine

Objectives Choline and ethanolamine are essential building blocks for the biosynthesis of cell-membrane phospholipids. Owing to accelerated proliferation, tumor cells have an increased demand for new membrane constituents and thereby rely on the uptake of choline and ethanolamine among other membrane components. [C-11]choline is a widely used PET tracer for prostate cancer imaging including the [F-18]derivatives fluormethyl- and fluoroethylcholine.

Methods It has been shown that the uptake of [C-14]ethanolamine and [C-14]dimethyl-aminoethanol is higher than the uptake of [C-14]choline in various cell lines (Mintz et al. Cancer Biol Ther 2008;7:1). Therefore, we synthesized a series of N-substituted N-([F-18]fluoroethyl)-2-aminoethanol derivatives (substituents H, Me, Et) and investigated them in comparison to [F-18]fluoroethylcholine for their acumulation in tumor cell lines with a focus on prostate tumors.

Results We could show that the respective [F-19]ethanolamine derivatives were able to effectively compete with [H-3]ethanolamine and [H-3]choline for uptake into tumor cells. The uptake and kinetics of the [F-18]ethanolamine derivatives into PC-3, Hep G2, Du-145, HCT-116, A375 and A549 cells proved to be better than the uptake of [F-18]fluoroethylcholine.

Conclusions Among the three aminoalcohol derivatives N-methyl-N-([F-18]fluoroethyl)-2-aminoethanol (FE-AA1) showed the best in vitro and in-vivo results