Proteomics approach in classifying the biochemical basis of the anticanceractivity of the new olomoucine-derived synthetic cyclin-dependent kinase inhibitor, bohemine

The aim of this study was to use two-dimensional electrophoresis (2-DE) cou pled with multivariate principal component analysis (PCA) to characterize t he quantitative changes in the protein composition of the CEM T-lymphoblast ic leukemia cell line after treatment with bohemine (BOH), a synthetic olom oucin-derived cyclin-dependent kinase inhibitor (CDKI). Cell classification , reflecting protein patterns, clearly distinguished two main groups: one g roup consists of 9, 12 and 24 h treated BOH cells while the second is repre sented by the 0 and 24 h control untreated cells and the 6 h BOH-exposed CE M lymphoblasts. Discriminant protein spots differentially expressed in the BOH-treated CEM cells were selected for identification by matrix assisted l aser desorption/ionization-mass spectrometry (MALDI-MS) or electrospray ion ization-tandem MS (ESI-MS/MS). Five of the selected protein spots were uneq uivocally identified as m-enolase, triosephosphate isomerase, eukaryotic in itiation factor 5A, and alpha- and beta -subunits of Rho GDP-dissociation i nhibitor 1. These proteins, all significantly downregulated in CEM T-lympho blast leukemia in the course of BOH treatment, are known to play an importa nt role in cellular functions such as glycolysis, protein biosynthesis, and cytoskeleton rearrangement. These results indicate that the cellular effec ts of olomoucine-derived CDKIs are not dependent on their ability to inhibi t CDKs and could be mediated by several factors such as a decrease in prote in synthesis and/or glycolysis which in turn diminishes the ability of canc er cells to function.