Pharmacoproteomic and toxicoproteomic study of the natural product Ebenfuran III in DU-145 prostate cancer cells using iTRAQ with 2D LC and tandem mass spectrometry

Ebenfuran III is a novel 2-arylbenzofuran isolated from Onobrychis ebenoides (Leguminosae) which exerts a significant cytotoxic effect on numerous cancer cells [1]. Within the context of our on-going cancer chemoprevention research, the aim of the present study was to evaluate the cytotoxicity of Eb III on DU-145 prostate cancer cells using relative quantitative proteomics approaches. The cells were exposed to Eb III for 12, 24 and 36h and the extracted proteins were labeled by iTRAQ after trypsinization. The labeled peptides were analyzed by multidimensional liquid chromatography combined with nanoESI and high resultion tandem mass spectrometry using a hybrid QqTOF instrumental method [2]. We compared the expression levels of 1361 proteins commonly present in control and treated cells at the different time points. Of these, 296 proteins were found to be significantly effected by Eb III (p≤0.05). Using bioinformatics and biological interpretation, multiple pathways were expressed that confirmed our existing knowledge base and extended our insight on the multi-focal pharmacodynamic effects of Eb III. Our results demonstrate the applicability of using a gel-free, quantitative LC-MS based proteomic approach for the global pharmacologic characterization of medicinal agents in ex vivo models.

References: 1. Katsanou ES, et al. (2007)J Steroid Biochem Mol Biol. 104:228–36. 2. Garbis SD, et al. (2008)J Proteome Res. In press