ggti-297 and Lung-Neoplasms

Ras malignant transformation requires posttranslational modification by farnesyltransferase (FTase). Here we report on the design and antitumor activity, in monotherapy as well as in combination therapy with cytotoxic agents, of a novel class of non-thiol-containing peptidomimetic inhibitors of FTase and the closely related family member geranylgeranyltransferase I (GGTase I). The non-thiol-containing FTI-2148 is highly selective for FTase (IC50, 1.4 nM) over GGTase I (IC50, 1700 nM), whereas GGTI-2154 is highly selective for GGTase I (21 nM) over FTase (IC50, 5600 nM). In whole cells, the corresponding methylester prodrug FTI-2153 is >3000-fold more potent at inhibiting H-Ras (IC50, 10 nM) than Rap1A processing, whereas GGTI-2166 is over 100-fold more selective at inhibiting Rap1A (IC50, 300 nM) over H-Ras processing. Furthermore, FTI-2153 was highly effective at suppressing oncogenic H-Ras constitutive activation of mitogen-activated protein kinase and human tumor growth in soft agar. FTI-2148 suppressed the growth of the human lung adenocarcinoma A-549 cells in nude mice by 33, 67, and 91% in a dose-dependent manner. Combination therapy of FTI-2148 with either cisplatin, gemcitabine, or Taxol resulted in a greater antitumor efficacy than monotherapy. GGTI-2154 in similar antitumor efficacy experiments is less potent than FTI-2148 and inhibits tumor growth by 9, 27, and 46%. Combination therapy of GGTI-2154 with cisplatin, gemcitabine, or Taxol is also more effective. Finally, FTI-2148 and GGTI-2154 are 30- and 33-fold more selective and 30- and 16-fold more potent in whole cells than our previously reported thiol-containing FTI-276 and GGTI-297, respectively. Thus, our results demonstrate that this highly potent and selective novel class of non-thiol-containing peptidomimetics inhibits human tumor growth in whole animals and that combination therapy with cytotoxic agents is more beneficial than monotherapy.

Topics: 3T3 Cells; Adenocarcinoma; Alkyl and Aryl Transferases; Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Benzamides; Cell Division; Cisplatin; Deoxycytidine; Enzyme Inhibitors; Farnesyltranstransferase; Gemcitabine; Humans; Lung Neoplasms; Mice; Mice, Nude; Mitogen-Activated Protein Kinases; Molecular Structure; Oligopeptides; Paclitaxel; rap1 GTP-Binding Proteins; ras Proteins; Transplantation, Heterologous; Tumor Cells, Cultured

The ability of Ras oncoproteins to cause malignant transformation requires their post-translational modifications by prenyl groups. Because K-Ras can be both farnesylated and geranylgeranylated it is not known whether both farnesyltransferase and geranylgeranyltransferase I inhibitors are required for suppressing human tumor growth in whole animals. In this paper we report that oncogenic Ras processing, MAP kinase activation and growth in nude mice are inhibited by the farnesyltransferase inhibitor FTI-276 in H- and N-Ras transformed NIH3T3 cells; whereas in KB-Ras transformed NIH3T3 cells both FTI-276 and the geranylgeranyltransferase I inhibitor GGTI-297 are required for inhibition. Furthermore, human lung A-549 and Calu-1 carcinoma cell lines were found to co-express H-, N- and K-Ras. In Calu-1 cells, the processing of H- and N-Ras is inhibited greatly by FTI-276 but only partially by GGTI-297 whereas K-Ras processing inhibition requires both FTI-276 and GGTI-297. In contrast, in A-549 cells the processing of H- and N-Ras is inhibited only by FTI-276 and K-Ras processing is resistant to co-treatment with FTI-276 and GGTI-297. Yet, the growth in nude mice of A-549 and Calu-1 xenografts, both of which express K-Ras mutations, is inhibited by FTI-276 (80% inhibition) and GGTI-297 (60%). Furthermore, FTI-276 inhibits tumor growth of NIH3T3 cells transformed by a form of oncogenic H-Ras that is exclusively geranylgeranylated and whose processing is resistant to this inhibitor. Taken together, the results demonstrate that both FTase and GGTase I inhibitors are required for inhibition of K-Ras processing but that each alone is sufficient to suppress human tumor growth in nude mice.

Topics: 3T3 Cells; Alkyl and Aryl Transferases; Animals; Benzamides; Cell Division; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Lung Neoplasms; Methionine; Mice; Mice, Nude; Neoplasm Transplantation; Oncogene Protein p21(ras); Protein Prenylation; Signal Transduction