Purpose
Melanoma is a solid tumor that is notoriously resistant to chemotherapy, and its incidence is rapidly increasing. Recently, several signaling pathways have been demonstrated to contribute to melanoma tumorigenesis, including constitutive activation of MAP kinase, Akt and Stat-3. The activation of multiple pathways may account in part for the difficulty in treatment of melanoma. In a recent screen of compounds, we found that an organopalladium compound, tris (dibenzylideneacetone) dipalladium (Tris DBA), demonstrated significant antiproliferative activity against melanoma cells. Studies were carried out to determine the mechanism of action of Tris DBA
Experimental Design
Tris DBA was tested on efficacy on proliferation of human and murine melanoma cells. In order to find the mechanism of action of Tris DBA, we performed Western Blot analysis and gene array analysis. The ability of Tris DBA to block tumor growth in vivo was assessed.
Results
(Tris DBA), has activity against B16 murine and A375 human melanoma in vivo. Tris DBA inhibits several signaling pathways including activation of MAP kinase, Akt, Stat-3 and S6 kinase activation, suggesting an upstream target. Tris DBA was found to be a potent inhibitor of N-myristoyltransferase 1 (NMT-1), which is required for optimal activity of membrane based signaling molecules. Tris DBA demonstrated potent antitumor activity in vivo against melanoma.
Conclusion
Tris DBA is thus a novel inhibitor of NMT-1 with significant antitumor activity and is well tolerated in vivo. Further preclinical evaluation of Tris DBA and related complexes is warranted.