Association of Ras protein with the inner surface of the plasma membrane is required for Ras signaling activity. Farnesyl thiosalicylic acid (FTS) amide is an FTS derivative with an amide added to the carboxyl group. FTS amide inhibits the growth of PANC-1 and U87 tumor cells with IC50 values of 20 and 10 μM, respectively, a relatively higher potency compared to that of FTS (IC50s = 35 and 50 μM, respectively). Treatment of nude mice bearing either U87 glioblastoma or PANC-1 tumors with 100 mg/kg FTS amide twice daily for four days inhibits tumor growth by at least 50% of controls.
