The Center for Alternatives to Animal Testing is an academic center affiliated with the Division of Toxicological Sciences in the Department of Environmental Health Sciences of the Johns Hopkins University Bloomberg School of Public Health.

 

Johns Hopkins School of Public Health

Abstract for TestSmart--A Humane and Efficient Approach to Screening Information Data Sets (SIDS) Data

Pharmacoproteomics to Profile Mechanisms of Drug Action and Toxicity

Sandra Steiner, Ph.D.
Large Scale Biology Corp.

The availability of large amounts of DNA sequence information and the progress in genomics and proteomics technologies has created a unique opportunity to accelerate the pharmaceutical drug discovery and development process. The possibility to monitor changes in gene expression present during disease development or resulting from therapeutic intervention will dramatically increase our understanding of biological processes and therapies. DNA array technologies are promising tools to quantify gene transcripts, however, transcript profiles are providing only a snapshot of gene expression and are poorly correlated with final protein profiles. It is important to emphasize that proteins reflect the biological phenotype, represent the vast majority of drug targets and mediate many of the molecular effects associated with therapeutic interventions. Hence, approaches allowing high-throughput analysis of expressed protein complements, the proteomes, are necessary to complete the picture. Proteomics include the quantitative measurements of proteins expressed by a genome, identification of post-translational protein modifications and determination of cellular and subcellular protein localization, which are all features closely associated with protein function. Presently the drivers of proteomics are high-resolution two-dimensional gel electrophoresis, mass-spectrometry and bioinformatics.

Therapeutic intervention is almost always associated with changes in gene- and protein expression, generating specific molecular imprints for individual drugs. Such drug-induced imprints, which can be visualized by proteome analysis, bear valuable information on a drug's mechanism of action and mechanism of toxicity. At LSB, over the past decade, we have performed and published (see list of references) a whole series of proteomics proof-of-concept studies in the area of toxicology and safety assessment. Applications in rodent tissue include the monitoring of therapeutic versus toxicity mechanisms, comparing compound mechanisms via SAR, detecting covalent protein adducts or protein phosphorylation, recognizing mechanism similarities across classes of therapies, linking toxic and therapeutic mechanisms or employing functional genomics via antisense effects in vivo. In addition to results obtained from various proof-of-concept studies, the data set we have accumulated in our Molecular Effects of Drugs (MED™) database also contains a number of reference compounds with known toxicity. The MED™ is a crucial component of our proteomics platform and forms the basis to compare molecular imprints, to cluster drug treatment effects and to assess the safety of new drug-candidates.