Mutational activation of ras oncogene products (p21s) is involved in the loss of growth control in a high percentage of human tumors. Consequently, significant attention has focused on defining the biochemistry and pharmacology of p21s, with the ultimate goal of developing inhibitors of p21 to be used as antitumor drugs. P21s require extensive post-translational processing to express optimal transforming ability, including attachment of farnesyl and palmitoyl moieties to cysteine residues near the C-terminus. Several inhibitors of farnesyltransferase have been described; however, no selective inhibitors of the palmitoylation step have yet been reported. The applicant has identified the natural product cerulenin as the first compound with such anti-p21 activity. The compound potently inhibits the proliferation of H-ras-transformed cells in parallel with inhibition of palmitate incorporation into p21 and accumulation of p21 in the cell cytosol. In contrast, cerulenin does not inhibit lipid acylation or protein myristoylation. Preliminary structure-activity studies indicate that cerulenin analogs can be efficiently synthesized, which will allow optimization of potency and selectivity for p21:acyltransferase. Studies to be conducted will further define the biochemical and cellular mechanisms of action of cerulenin and analogs, with focus on its inhibition of p21 processing. The selectivity of the actions of these compounds toward palmitoylated species of p21 versus K-ras p21 will be determined. P21:acyl-transferase will be isolated and characterized at both the protein and DNA level. Cerulenin analogues will be synthesized and tested for activity in cell- and enzyme-based assays, and as antitumor agents for xenografts of ras-transformed cells. These studies should allow evaluation of p21:acyltransferase as a target for new anticancer drugs.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Project (R01)
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Experimental Therapeutics Subcommittee 1 (ET)
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Johnson, George S
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Fox Chase Cancer Center
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Draper, Jeremiah M; Smith, Charles D (2010) DHHC20: a human palmitoyl acyltransferase that causes cellular transformation. Mol Membr Biol 27:123-36
Draper, Jeremiah M; Smith, Charles D (2009) Palmitoyl acyltransferase assays and inhibitors (Review). Mol Membr Biol 26:5-13
Seaton, Kelly E; Smith, Charles D (2008) N-Myristoyltransferase isozymes exhibit differential specificity for human immunodeficiency virus type 1 Gag and Nef. J Gen Virol 89:288-96
Draper, Jeremiah M; Xia, Zuping; Smith, Charles D (2007) Cellular palmitoylation and trafficking of lipidated peptides. J Lipid Res 48:1873-84
Ducker, Charles E; Griffel, Lindsay K; Smith, Ryan A et al. (2006) Discovery and characterization of inhibitors of human palmitoyl acyltransferases. Mol Cancer Ther 5:1647-59
Ducker, Charles E; Upson, John J; French, Kevin J et al. (2005) Two N-myristoyltransferase isozymes play unique roles in protein myristoylation, proliferation, and apoptosis. Mol Cancer Res 3:463-76
Ducker, Charles E; Stettler, Erin M; French, Kevin J et al. (2004) Huntingtin interacting protein 14 is an oncogenic human protein: palmitoyl acyltransferase. Oncogene 23:9230-7
Varner, Amanda S; Ducker, Charles E; Xia, Zuping et al. (2003) Characterization of human palmitoyl-acyl transferase activity using peptides that mimic distinct palmitoylation motifs. Biochem J 373:91-9
Varner, Amanda S; De Vos, Mackenzie L; Creaser, Steffen P et al. (2002) A fluorescence-based high performance liquid chromatographic method for the characterization of palmitoyl acyl transferase activity. Anal Biochem 308:160-7
Xia, Z; Smith, C D (2001) Efficient synthesis of a fluorescent farnesylated Ras peptide. J Org Chem 66:5241-4

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