Quantitative single analysis of c-Jun/AP-1 for clinical studies
Shao-Ju Ryan Lu1, Ed Tate1, Keith Willison1, David Klug1*
1Institute of Chemical Biology, Department of Chemistry, Imperial College, UK
Both c-Jun and its dimerization partners in transcription factor AP-1 formation play important roles in cell proliferation, apoptosis and cell transformation. AP-1/c-Jun is documented to be one of the key activators in breast cancer. AP-1-mediated regulation determined cell fates critically depends on the relative abundance of AP-1 subunits. However, bulk measurements of AP-1/c-Jun levels do not record the intrinsic and extrinsic variation in cellular responses across a population of cells, thereby masking the individual details.
We have developed a label-free, microfluidic antibody chip platform called the MAC chip 1 , to quantify precisely the copy numbers of many proteins from a single cell. Utilizing microfluidic strategies along with optical trapping and lysis techniques, we have established c-Jun assay which is capable of quantification of c-Jun, phospho-c-Jun and its homodimer complex individually at the single cell level. Furthermore, the protein assays can now be accomplished in a multiplexed single assay format.
We are working on investigations into protein noise in tumor cells isolated from biopsies of cancer patients through the identification of biomolecular signatures. 2 Using patient-derived colorectal cancer xenografts as proof-of-concept, we have demonstrated a potential route for moving single cell proteomics into medical diagnostics. Our aim is to integrate the protein measurements with single cell transcriptomics. In the future, we hope to gain deep insights into c-Jun transcriptional and translational regulation at the single cell level.
1.E. Burgin, A. Salehi-Reyhani, M. Barclay, A. Brown, J. Kaplinsky, M. Novakova, M. A. A. Neil, O. Ces, K. R. Willison, and D. R. Klug, Analyst, 2014, 139, 3235–44.
2.K. R. Willison and D. R. Klug, Curr. Opin. Biotechnol., 2013, 24, 745–51.