Mammary tumor and melanoma cell transport of PTT.119, a bis-(2-chloroethyl)amino-L-phenylalanine derivative with carrier amino acids.

Uptake of the bifunctional alkylating agent, PTT.119, p-F-Phe-m-bis-(2-chloroethyl)amino-L-Phe-Met-ethoxy-HCl, by the MJY-alpha mammary tumor and B16 melanoma cell lines occurred via two natural pathways for amino acid transport. The primary route of PTT.119 entry was the classical L System, whereas, the ASC System carrier was inconsistently operational for uptake of the tripeptide accounting for 5-6% of PTT.119 transport in the B16 melanoma cells. Tripeptide uptake by MJY-alpha mammary tumor cells did not occur via ASC carriers indicating that the mechanism of drug transport was dissimilar among the tumor cells. In spite of these differences the results support the hypothesis that amino acid residues covalently linked to an alkylating moiety do serve as carriers to enhance drug delivery.