The paper states that the assay has sensitivity equivalent tyramide signal amplification with the added feature of two channels or colours, effectively doubling the number of endpoints that can be analysed with a fixed number of arrays.
The study, which was published by Dr. Emanuel Petricoin in a recent issue of Clinical Proteomics Journal, has wide reaching implications in the area of proteomics which aims to characterize and develop 'circuit maps' of cellular signalling pathways in normal and diseased cells. Defective, hyperactive, or dominating signal pathways may drive cancer growth, survival, invasion, and metastasis.
The study uses a dual dye based approach that can effectively double the number of endpoints observed per array allowing both phophospecific and total protein levels to be measured and analysed at once. The method utilizes antibody bound dyes that emit in the infrared spectral region as a means of sensitive and specific detection.
Reverse phase arrays, where the array consists of immobilized analytes and lysates has especially shown promise in low abundance analyte detection and signal pathway profiling using phopho-specific antibodies. A limitiation to current reverse phase array methodology is the inability to multiplex proteomic-based endpoints as each array can only report one analyte endpoint.
An example to the effectiveness of these arrays would see information flow through signalling pathways in normal and cancer cells serve as a means to identify key alterations that occur during tumour progression and provide targets for rational, molecular-targeted drug design.
With the advent of molecular targeted therapeutics, the identification, characterization, and monitoring of the signalling events within actual human biopsies will be critical for patient-tailored therapy.
As the drug discovery field focuses on the development of molecular-targeted therapeutics, the activity status of pathways and phosphorylated levels of kinase substrate targets of interest in individual tumours will become the major focal pojnt of analysis.
The detection of subtle changes in the activity of various signalling pathways in normal and tumour tissue in a patient is not only valuable scientifically for the study of disease progression, but will be essential for appropriate treatment selection and monitoring treatment efficacy in the future.
As the drug development pipeline is heavily skewed towards signal pathway modulators and kinase inhibitors. The ability to determine and understand treatment effectiveness, via protein microarrays, which can analyse both the drug target and the entire pathway network, may lead to better patient management and better clinical outcomes.