The long-term objective of this application is to accelerate cancer chemoprevention research by establishing Drosophila melanogaster as a platform for the genetic and pharmacological study of Keap1-Nrf2 signaling. Preliminary findings suggest that the Drosophila homologues of Nrf2 and Keap1 (CNC-C and dKeap1, respectively) comprise a cell protective module that responds to oxidants and to the chemopreventive agent oltipraz, regulates stress-inducible genes, and confers increased tolerance of the fly to oxidative stress. This project will characterize the effects of oltipraz and of the new synthetic triterpenoids (provided by Dr Michael B. Sporn, Dartmouth Medical School) on the activation of Drosophila Nrf2 (CNC-C) signaling. Functional experiments will determine the mechanisms of action and physiological effects of these chemopreventive drugs in Drosophila. By conducting experiments in genetic backgrounds of gain- or loss-of-function for Nrf2 or Keap1 that have been developed in the laboratory of the applicant, the signaling pathway mediating the activation of the Anti-oxidant Response Element and the expression of Nrf2 target genes will be charted. Biological assays will monitor the effects of oltipraz and triterpenoids on the organism's resistance to oxidative stressors and on its lifespan. Together, these experiments will establish a genetically tractable system for studying the effects of pharmacological manipulation of Nrf2 signaling in an intact organism that is complementary to existing rodent, fish, and cell-based model systems. This work will be the starting point from which the power of Drosophila genetics will help to address crucial clinical issues of chemoprevention. Future research that will become feasible upon completion of these pilot studies will analyze the integration of the Nrf2 system with other mechanisms of stress response and defense in vivo, providing a basis for rational design of combinatorial targeting strategies. Furthermore, the evaluation of long-term organismal effects of chemopreventive agents in Drosophila could help prioritize drugs with quality-of-life promoting profiles for further preclinical development. Finally, Drosophila could become a platform for rapid in vivo structure-activity relationship (SAR) analyses of Nrf2 activators. ? ? ?
| Sekyrova, Petra; Bohmann, Dirk; Jindra, Marek et al. (2010) Interaction between Drosophila bZIP proteins Atf3 and Jun prevents replacement of epithelial cells during metamorphosis. Development 137:141-50 |
| Sykiotis, Gerasimos P; Bohmann, Dirk (2010) Stress-activated cap'n'collar transcription factors in aging and human disease. Sci Signal 3:re3 |
| Sykiotis, Gerasimos P; Bohmann, Dirk (2008) Keap1/Nrf2 signaling regulates oxidative stress tolerance and lifespan in Drosophila. Dev Cell 14:76-85 |
