A trichostatin A expression signature identified by TempO-Seq targeted whole transcriptome profiling.

The use of gene expression signatures to classify compounds, identify efficacy or toxicity, and differentiate close analogs relies on the sensitivity of the method to identify modulated genes. We used a novel ligation-based targeted whole transcriptome expression profiling assay, TempO-Seq®, to determine whether previously unreported compound-responsive genes could be identified and incorporated into a broad but specific compound signature. TempO-Seq exhibits 99.6% specificity, single cell sensitivity, and excellent correlation with fold differences measured by RNA-Seq (R2 = 0.9) for 20,629 targets. Unlike many expression assays, TempO-Seq does not require RNA purification, cDNA synthesis, or capture of targeted RNA, and lacks a 3' end bias. To investigate the sensitivity of the TempO-Seq assay to identify significantly modulated compound-responsive genes, we derived whole transcriptome profiles from MCF-7 cells treated with the histone deacetylase inhibitor Trichostatin A (TSA) and identified more than 9,000 differentially expressed genes. The TSA profile for MCF-7 cells overlapped those for HL-60 and PC-3 cells in the Connectivity Map (cMAP) database, suggesting a common TSA-specific expression profile independent of baseline gene expression. A 43-gene cell-independent TSA signature was extracted from cMAP and confirmed in TempO-Seq MCF-7 data. Additional genes that were not previously reported to be TSA responsive in the cMAP database were also identified. TSA treatment of 5 cell types revealed 1,136 differentially expressed genes in common, including 785 genes not previously reported to be TSA responsive. We conclude that TSA induces a specific expression signature that is consistent across widely different cell types, that this signature contains genes not previously associated with TSA responses, and that TempO-Seq provides the sensitive differential expression detection needed to define such compound-specific, cell-independent, changes in expression.

Third Santorini conference pharmacogenomics workshop report: "Pharmacogenomics at the crossroads: what else than good science will be needed for the field to become part of Personalized Medicine?".

This workshop discussed the use of pharmacogenomics knowledge in clinical practice. It was organized in three sections: educational needs, definition of industry as a potential trigger, and regulatory aspects. Regarding pharmacogenomics education, it appears that this is truly lacking, except for patients, who are becoming increasingly educated thanks to the media. Regarding administrators, education is mainly a problem of cost. Indeed, even if cost-effective for society on the whole, pharmacogenomic tests will be expensive for hospitals. Physicians are facing an overabundance of information. They must be helped to bridge the gap between knowledge/research and clinical application. Collaboration between the pharmaceutical industry and the diagnostics industry could be one of the triggers. Moreover, there is a lack of qualification of this information, even though some guidelines are being produced. The Food and Drug Administration organizes workshops that often lead to publications on pharmacogenomic education, genomic data aims and development concepts, which can finally be translated into guidelines. Industry can contribute to pharmacogenomic development, not only through research, but also through marketing activities, which would promote the use of pharmacogenomics by physicians. Legal aspects were also considered in terms of the problem of availability and the degree of qualification of commercial drug tests on the market. The Innovative Medicine Initiative was also presented, which is a public-private partnership to create a biomedical research and development leader to benefit patients and society. Finally, a technical report from the Institute for Prospective Technological Studies on the socioeconomic impact of pharmacogenomics in the EU was presented.