PROTEIN FARNESYLTRANSFERASE INHIBITORS BLOCK THE GROWTH OF RAS-DEPENDENT TUMORS IN NUDE-MICE

The posttranslational addition of a farnesyl moiety to the Ras oncoprotein is essential for its transforming activity. Cell-active inhibitors of the enzyme that catalyzes this reaction, protein farnesyltransferase, have been shown to selectively block ras dependent transformation of cells in culture. Here we describe the protein farnesyltransferase inhibitor 2(S)-[2(S)-[2(R)-amino-3-mercapto]propylamino-3(S)-methyl] pentyloxy-3-phenylpropionylmethioninesulfone methyl ester (L-739,749), which suppressed the anchorage independent growth of Rat1 cells transformed with viral H-ras and the human pancreatic adenocarcinoma cell line PSN-1, which harbors altered K-ras, myc, and p53 genes. This compound also suppressed the growth of tumors arising from ras-transformed Rat1 cells in nude mice by 66%. Under the same conditions, doxorubicin inhibited tumor growth by 33%. Control tumors formed by v-raf or v-mos transformed Rat1 cells were unaffected by L-739,749. Furthermore, mice treated with L-739,749 exhibited no evidence of systemic toxicity. This is a demonstration of antitumor activity in vivo using a synthetic small molecule inhibitor of protein farnesyltransferase.