*3.5. Cytotoxicity Assays*

A modified propidium iodide assay was used to examine the antiproliferative activity of the compounds against human tumor cell lines. Cell lines tested were derived from patient tumors engrafted as a subcutaneously growing tumor in NMRI nu/nu mice or obtained from American Type Culture Collection, Rockville, MD, USA, National Cancer Institute, Bethesda, MD, USA, or Deutsche Sammlung von Mikroorganismen und Zellkulturen, Braunschweig, Germany, and details of the test procedure have been described previously [20–22]. For the results, see Table 3.
