New farnesyltransferase inhibitors in the phenothiazine series.

The biological screening of the chemical library of our Organic Chemistry Department, carried out on an automated fluorescence-based FTase assay, allowed us to discover that a phenothiazine derivative (1d) was an inhibitor of farnesyltransferase. Three new series of human farnesyltransferase inhibitors, based on a phenothiazine scaffold, were synthesized with protein farnesyltransferase inhibition potencies in the low micromolar range. Ester derivative 9d was the most active compound in these series. Four synthesized compounds were evaluated for their antiproliferative activity on a NCI-60 cancer cell line panel. The modest results obtained in this preliminary investigation showed that mixing the phenothiazine and the 1,2,3-triazole motif in the structure of a single compound can lead to new scaffolds in the field of farnesyltransferase inhibitors.