Protein farnesyl transferase as a target for the development of anticancer drugs

Protein farnesylation (addition of 15-carbon isoprene units), catalyzed by protein farnesyl transferase (FT), permits the anchoring of a number of cellular proteins to cell membranes, where they mediate their effects. Because farnesylated proteins including Ras, Rac, Rho and other small G-proteins are involved in cell transformation and proliferation, protein farnesyl transferase inhibitors (FTIs) have emerged as a novel class of antineoplastic agents. Four FTIs are currently in clinical trials, with two of them in phase II testing. Preliminary evidence of clinical activity has been documented in a number of tumor types including non-small cell lung cancer, breast cancer and leukemia. While the FTIs clearly inhibit FT, their mechanism of cytotoxicity is unclear. Also, because the cellular target of FTIs is known, there is considerable interest in developing markers of FT inhibition in patient tissues.