A new assay capable of examining hundreds of proteins at once has been developed by scientists from the University of Chicago and the Massachusetts Institute of Technology. The new micro-western arrays reportedly combine the specificity of the Western blot protein assay with the large scale of DNA microarrays.
The researchers say that the technique will allow scientists to observe much of a cell's intricate protein network in one experiment rather than peeking at one small piece at a time. Details appear in the paper “Systems analysis of EGF receptor signaling dynamics with micro-western arrays” published online in Nature Methods on January 24.
With Western blots, scientists are restricted to observing only a small fraction of protein activity with each experiment. Micro-western arrays adapt the technology of the microarray, typically used to assess the expression of thousands of genes in a single experiment, to proteins.
“The proteins are the actual machines that are doing everything in the cell, but nobody's been able to examine them in depth because it's been too complicated,” points out Richard B. Jones, Ph.D., senior author and assistant professor at the University of Chicago's Ben May department for cancer research and the Institute for Genomics and Systems Biology. “Now, we can begin to do that with this new method.”
To demonstrate the potential of the micro-western array, the investigators looked at the behavior of proteins in a cancer cell line with elevated amounts of epidermal growth factor receptor (EGFR). The experiments found that activating EGFR simultaneously activated several other receptors in the cell.
With more information, the method may potentially be used clinically for more precise diagnoses of cancer and other diseases, the scientists believe.
“In the clinic, you're limited by the fact that typically most cancers are diagnosed by one or two markers; you're looking for one or two markers that are high or low, then trying to diagnose and treat an illness,” Dr. Jones explains. “Here, we can potentially measure a collection of proteins at the same time and not just focus on one guess.”
Additionally, scientists in the field of systems biology say that micro-western arrays could make possible experiments that were previously beyond the scope of laboratory methods. “One of the biggest hurdles for systems biology is the struggle for high-density, dynamic, and quantitative data, and the micro-western array method will go a long way to address this problem,” according to Walter Kolch, director of Systems Biology Ireland and professor at University College Dublin.