title: Structure-activity relationship for alkylating dipeptide nitrogen mustard derivatives.
abstract: The strategy of using small peptides for effective targeting of tumor cells in chemotherapy has proven beneficial. Recently we showed that J1 (L-melphalanyl-p-L-fluorophenylalanine ethyl ester), an alkylating nitrogen mustard-containing dipeptide, exhibited strong cytotoxic activity in fresh human tumor samples in addition to rapid and pronounced inhibition of macromolecular syntheses and cellular respiration in the human tumor lymphoma cell line U-937 GTB. In this study, an additional series of 17 nitrogen mustard-containing dipeptides has been synthesized and analyzed for cytotoxic activity in a panel of 10 human tumor cell lines. The results were compared to the single amino acid mustard derivative melphalan and its ethyl and isopropyl esters. Also P2 (L-prolyl-m-L-sarcolysyl-p-L-fluorophenylalanine ethyl ester), a tripeptide that previously has shown impressive effects in human tumor cells, was used as reference. The tested compounds displayed various activities in the different cell lines but also showed a high correlation, indicating a similar mechanism of action. Factors like amino acid composition, amino acid sequence, modifications of the C- and N-termini, and to a minor extent the lipophilicity of the dipeptide derivatives appear to influence the in vitro activity. The results indicate that the activity of these compounds not only relies on their chemical reactivity, but also on active biological interactions such as transport across membranes and/or enzymatic liberation of reactive molecular entities.
authors.affiliation: Department of Medical Sciences, Division of Clinical Pharmacology, Uppsala University, SE-751 85 Uppsala, Sweden. Joachim.Gullbo@medsci.uu.se
authors.forename: Joachim
authors.initials: J
authors.lastname: Gullbo
authors.forename: Marcus
authors.initials: M
authors.lastname: Tullberg
authors.forename: Jon
authors.initials: J
authors.lastname: Våbenø
authors.forename: Hans
authors.initials: H
authors.lastname: Ehrsson
authors.forename: Rolf
authors.initials: R
authors.lastname: Lewensohn
authors.forename: Peter
authors.initials: P
authors.lastname: Nygren
authors.forename: Rolf
authors.initials: R
authors.lastname: Larsson
authors.forename: Kristina
authors.initials: K
authors.lastname: Luthman
mesh_terms: D000478:Alkylation / Q000187:drug effects; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D004151:Dipeptides / Q000737:chemistry*; D006801:Humans; D020128:Inhibitory Concentration 50; D015394:Molecular Structure; D009588:Nitrogen Mustard Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000633:toxicity*; D013329:Structure-Activity Relationship
chemical_list: D004151:Dipeptides; D009588:Nitrogen Mustard Compounds