Biomarkers
References 1 Biomarkers: A Market Insight Report (2008). Research Impact, MIR003. 2 Biomarkers Definitions Working Group (2001). Biomarkers and surrogate endpoints: preferred definitions and conceptual framework. Clin Pharmacol Ther 69, 89-95. 3 Eck, SL, Paul, SM (2010). Biomarker qualification via public-private partnerships. Clin Pharmacol Ther 87, 21-23. 4Wagner, JA et al (2010). The Biomarkers Consortium: practice and pitfalls of open- source precompetitive collaboration. Clin Pharmacol Ther 87,539-542. 5 Marrer, E, Dieterle, F (2008). Biomarkers in oncology drug development: rescuers or troublemakers? Expert Opin Drug Metab Toxicol 4, 1391- 1402. 6 Kulasingam, V et al (2010). Integrating high-throughput technologies in the quest for effective biomarkers for ovarian cancer. Nat Rev Cancer 10, 371-378. 7 Mattes, WB et al (2010). Research at the interface of industry, academia and regulatory science. Nat Biotech 28, 432-433 and numerous related articles in the same issue. 8 Marrer, E, Dieterle, F (2010). Impact of biomarker development on drug safety assessment. Toxicol Appl Pharmacol 243, 167-179. 9 Bhattacharya, S, Mariani, TJ (2009). Array of hope: expression profiling identifies disease biomarkers and mechanism. Biochem Soc Trans 37, 855-862. 10 Hoefkens, J (2010). Towards unbiased biomarker discovery. Drug Discovery World 11, 19- 24. 11 Poschmann, G et al (2009). Cell-based proteome analysis: the first stage in the pipeline for biomarker discovery. Biochim Biophys Acta 1794, 1309-1316.
Figure 3: The Operetta® instrument, a high-throughput imaging tool
Analyte binding serves to bridge the beads, bring- ing them into close proximity resulting in chemical energy transfer and creation of a strongly amplified luminescent signal with high sensitivity and large dynamic range. This signal can be read on versatile multilabel detection instruments such as the EnVision® multilabel reader or a lower cost dedi- cated EnSpire™ reader, both available from PerkinElmer Inc. Flexibility of Alpha technology for development of custom biomarker assays is achieved through availability of a variety of tool- box beads pre-coated with common affinity tags, or uncoated beads that can be used for direct con- jugation of capture antibodies by end-users. A selection of more than 60 validated AlphaScreen SureFire® kits are also available to measure acti- vation of kinases, signalling proteins and transcrip- tion factors in cell-based assays.
Continued on page 22 20
In conjunction with biochemical assays, cellular imaging analysis is increasingly used in biomarker research. Immunocytochemistry and immunohisto- chemistry can monitor level and localisation of biomarkers in cells and tissue sections, where the antibody is typically coupled to an enzyme, fluo- rophore or quantum dot in order to generate a visual readout. The possibility to monitor the pro- tein of interest in specific cells and to gain localisa- tion information by confocal microscopy make cel- lular imaging a powerful tool for biomarker appli- cations, however data generated by this technique
has historically been more subjective than quanti- tative, and opportunities for automation have been somewhat limited. Recent development of microplate-based high content imaging solutions interfaced to powerful data analysis software in systems such as the Opera® and Operetta® instru- ment from PerkinElmer Inc (Figure 3) enables high throughput imaging biomarker analysis for cellular models. In addition to measuring quantity and localisation of specific targets, critical cellular characteristics such as shape, nuclear morphology, and membrane integrity can also be accurately integrated to provide a comprehensive view of rel- evant biologies in intact cellular systems.
Label-free measurement: mass spectrometry
Immunoassay methods are restricted by the avail- ability of good quality antibodies that exhibit opti- mal specificity and avidity for their targets. However, specific epitopes can be modified either in vivo or during sample preparation (ie through post-translational modifications or proteolytic cleavage). While a particular antibody pair may identify a subset of the specific target population, multiple antibodies may be required to quantitate global levels of any particular biomarker. This can explain major discrepancies in measured levels of a given target using various kits developed by multi- ple providers, even when using the same assay
Drug Discovery World Summer 2010
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92