| Regional Biophysics Meeting 2005, March 16-20, Zreče, Slovenia | [MembBiophys] |
Alkylphospholipids (APLs) are interesting compounds with antineoplastic and immunomodulatory properties. Among them hexadecylphosphocholine (miltefosine) is already in use as anticancer drug. Because of its gastrointestinal (GI) toxicity, it is formulated for topical application in the clinical treatment of cutaneous breast cancer and other malignant lesions. Octadecyl-(1,1-dimethyl-4-piperidino-4-yl)-phosphate (perifosine) has significantly improved GI tolerance, especially in liposome preparations. The primary target of APLs is thought to be the plasma membrane but other mechanisms of their action on the molecular level are under discussion. Here the synthesis of spin-labeled analogs of miltefosine and perifosine is presented. We introduced the paramagnetic doxyl group into the alkyl chain of APLs changing the distance between doxyl and phosphate group. All compounds were characterized by standard chemical methods. Their cytotoxic activity (IC50) either in liposomes or in free solution was evaluated in vitro by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylterazolium bromide) test on three different breast cancer cell lines: MT1, MT3 and MCF7 in comparison to unlabeled compounds. We found that all tested compounds are 2-3 times less active than unlabeled one except compound (14P) having doxyl group on the 14th C atom from the phosphate group, which had cytotoxic effect similar to perifosine. The presented biological evaluation shows that the presence of doxyl group in the alkyl chain as well as its position has an important influence on their cytotoxic activity. Spin-labeled APLs analogs with comparable activity to perifosine can be important molecular tools in further studies using EPR spectroscopy.The availability of differently spin-labeled APL analogs of perifosine and miltefosine allows choosing an appropriate label for EPR spectroscopy to analyze in detail the membrane effect of APLs.
Email: janez.mravljak@ffa.uni-lj.si
Address: 1.Janez Mravljak, University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, 1000 Ljubljana, Slovenia, 2.Slavko Pečar, University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, 1000 Ljubljana, Slovenia and Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, 3.Reiner Zeisig, Max-Delbrück-Center for Molecular Medicine, 13092 Berlin-Buch, PF 74 02 38 AG Experimental Pharmacology, 13125 Berlin, Germany,