Background: (-)-Depudecin is a fungal metabolite that reverts the rounded phenotype of NIH3T3 fibroblasts transformed with v-ras and v-src oncogenes to the flat phenotype of the nontransformed parental cells. The mechanism of action of this detransformation agent is unknown. Although depudecin appears to be an excellent molecule for probing signaling pathways that regulate changes in the cytoskeletal architecture, reagents based on depudecin are not available as it has not yet been successfully synthesized. We therefore set out to synthesize (-)-depudecin. Results: An asymmetric synthesis of (-)-depudecin has been developed. A cell staining assay has been used to reveal the ability of synthetic depudecin, but not several structural variants, to induce a flattened morphology in v-Ha-ras-transformed NlH3T3 cells.This assay also shows that depudecin induces an intricate network of actin stress fibers in these cells and in MG63 osteosarcoma cells and reveals the essential role of the epoxide and hydroxyl moieties in depudecin. Cycloheximide and actinomycin D inhibited the ability of depudecin to induce a morphological change, suggesting that both mRNA synthesis and de novo protein synthesis are required for depudecin-mediated suppression of the transformed phenotypes in ras-transformed cells. Conclusions: The synthetic procedure provides access to (-)-depudecin and could be readily modified to produce depudecin-related reagents for the identification of depudecin's cellular target(s). This target appears to be involved in the regulation of the assembly of the actin microfilament component of the cytoskeleton in mammalian cells.
Bibliographical noteFunding Information:
Acknowledgements: We thank Dr Jon Collins for his help with the early stages of this work and Dr Andrew Tyler of the Harvard Mass Spectrometry Facility for providing mass spectra. We acknowledge the NIH BRS Shared Instrumentation Grant Program (1 SlO RRO174801) and NSF (CHE88-14019) for providing NMR facilities. J.S. is a visiting scientist from Kyowa Hakko Kogyo Co., Ltd, and M.S. was supported by a Fellowship from theYamada Science Foundation, Osaka, Japan. H.J.K. is a postdoctoral research associate S.L.S. is an Investigator at the Howard Hughes Medical
All Science Journal Classification (ASJC) codes
- Molecular Medicine
- Molecular Biology
- Drug Discovery
- Clinical Biochemistry