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Activated Drosophila Ras1 is selectively suppressed by isoprenyl transferase inhibitors
R C Kauffmann1, Y Qian, A Vogt
1Department of Biological Sciences, University of Pittsburgh, PA 15260, USA.
Abstract:
Ras CAAX (C = cysteine, A = aliphatic amino acid, and X = any amino acid) peptidomimetic inhibitors of farnesyl protein transferase suppress Ras-dependent cell transformation by preventing farnesylation of the Ras oncoprotein. These compounds are potential anticancer agents for tumors associated with Ras mutations. The peptidomimetic FTI-254 was tested for Ras1-inhibiting activity in whole animals by injection of activated Ras1val12 Drosophila larvae. FTI-254 decreased the ability of Ras1val12 to form supernumerary R7 photoreceptor cells in the compound eye of transformed flies. In contrast, it had no effect on the related supernumerary R7 phenotypes of flies transformed with either the activated sevenless receptor tyrosine kinase, Raf kinase, or a chimeric Ras1val12 protein that is membrane associated through myristylation instead of isoprenylation. Therefore, FTI-254 acts as an isoprenylation inhibitor to selectively inhibit Ras1val12 signaling activity in a whole-animal model system.
Insights
Ras CAAX peptidomimetic inhibitors, like FTI-254, block Ras protein farnesylation. This study shows FTI-254 selectively inhibits Ras signaling in Drosophila, demonstrating potential as an anticancer agent.
Area of Science:
- Biochemistry
- Molecular Biology
- Oncology
Background:
- Ras oncoproteins are key regulators of cell signaling.
- Aberrant Ras signaling drives many human cancers.
- Farnesyl protein transferase (FPTase) inhibitors target Ras farnesylation.
Purpose of the Study:
- To evaluate the in vivo efficacy of Ras CAAX peptidomimetic FTI-254.
- To determine if FTI-254 selectively inhibits Ras signaling in a whole-animal model.
Main Methods:
- Utilized Drosophila melanogaster as a whole-animal model.
- Injected activated Ras1val12 Drosophila larvae with FTI-254.
- Assessed R7 photoreceptor cell formation in compound eyes.
Main Results:
- FTI-254 significantly reduced Ras1val12-induced supernumerary R7 cells.
- FTI-254 did not affect phenotypes caused by activated Sevenless or Raf.
- FTI-254 showed no effect on myristoylated Ras1val12 signaling.
Conclusions:
- FTI-254 selectively inhibits Ras isoprenylation and downstream signaling in vivo.
- Ras CAAX peptidomimetics are promising therapeutic agents for Ras-driven cancers.