Protein biomarker discovery: proteomics application in translational research

In this section, we are talking about protein biomarker discovery. I am Dr. Cheng. This topic is an issue about proteomic application in translational medicine. Protein biomarker discovery is integrate many components of translational

medicine including: clinical on Med, bench side, and personal medicine. There are two major techniques are involved in protein biomarker discovery by proteomics. First, two dimensional electrophoresis was applied to identify the differentially expressed proteins between normal and deceased subjects. Then, MALDI-TOF mass spectrometry were applied to identify differentially expressed proteins in cancer specimens and summarize the identify the protein and their gene length. In this section, using lung cancer for example to elucidate, lung cancer biomarkers development procedure. Normal lung cell and lung cancer adenocarcinoma cells are used to identify differentially expressed proteins extract cell membrane proteins (then running two- dimensional electrophoresis to separate individual proteins spot in gel.

Mass spectrum is applied to identify the differentially expressed proteins. In this example, between these two groups, 8 clusters of protein spots were significantly different in protein level. Capture the differential express protein to identify by MALDI-TOF Mass spectrum analysis. Then evaluate the functional activities of each protein. After evaluate the functional activities of differential expressed proteins according selected candidate protein to develop detection tool. In this experiment, Galectin-1 significance increase in cancer cell and affect the cell activity. Selecting Galectin-1 as a lung cancer protein biomarker candidate clone and produce galectin-1 protein to develop antibody for diagnosis and targeting use.

Monoclonal antibody production is a common use tool to create detection antibody. First, we need to immunize mice with candidate protein. When mice plasma, Anti-Galectin-1 antibody titer are increased, sacrifice the mice and harvest the spleen cell then fusions the spleen cell with myeloma cell. The fused cell named hybridoma. Hybridoma will exist on limited population and antibody production activity. Screen monoclonal antibody by Galectin-1 coded ELISA plate. In this step, hybridoma culture medium are used for test. After screening, developed monoclonal antibodies could be used to detect disease protein biomarkers.

This biomarker can be further application for clinical diagnosis or targeting serum to be used. Thank you for your attention.