Cancer Biomarker Discovery---From Establishment of Cancer-Cell Secretome Dataset to Multiplex Quantitation of Multiple Biomarkers

Cancer is one the main causes of human death in the world. Most of the cancer in human when been diagnosed belongs to the middle or late stages, which leads to the high mortality rate of cancer. In addition to keeping a healthy life style, the best way to fight cancer is to diagnose it early. Although effective serum tumor markers are rare at present, diagnosis of cancer by checking tumor markers in serum/plasma is the most convenient way in clinic. Therefore, looking for effective serum tumor markers is an important issue for the success of early diagnosis of cancer. Proteomic analysis of protein expression in tumor/normal tissue and/or in serum/plasma from cancer patients/normal healthy controls represents one of the powerful approaches to search tumor markers systematically. For proteomic approach, the task will be the extremely complicated compositions of clinical specimens, which usually causes the analysis being not reproducible. In the last two years, we have tried to develop an alternative proteomic approach to address this issue. We focused on analysis of the secreted proteome from various human cancer cell lines, and tried to find potential biomarkers in these secreted protein databases. Through the technology platforms developed in the Chang-Gung Proteomics Core Lab, we have analyzed, by simply conbiming SDS-PAGE and MALDI-TOF MS analtsis, the secreted proteins from two nasopharyngeal carcinoma (NPC) cell lines originally established in Taiwan. From more than 20 proteins commonly secreted in both NPC cell lines, two proteins were selected and validated as potential biomarkers (by immunohistochemistry and sandwich fluorimetric ELISA) using clinical specimens (tissue biopsies and serum samples) from NPC patients and healthy controls, or from a xenografted mouse tumor model (Wu et al., Proteomics 5, 3173-3182, 2005). In addition, we have also analyzed the secreted proteomes from other 24 cell lines derived from 14 common human cancers, including colorectal and oral cancer cell lines. The expression level of certain proteins in colorectal and oral cancer specimens has also been confirmed by immunohistochemistry and ELISA as well. On the basis of the results described above, we attempt to address the following issues in this 3-year proposal: (1) To systematically analyze the secreted proteomes from ~30 human cancer cell lines with different tumor origins by LC-MS/MS for the establishment of a more comprehensive cancer cell secretome dataset; (2) To integrate Cy dye labeling/LC/SDS-PAGE/MALDI-TOF MS for tumor marker discovery in serum/plasma samples from xenograft mouse tumor model and cancer patients; (3) To develop a microscopic bead-based, multiplex biomarker quantitation platform for determine the level of multiple targets in human serum/plasma samples in a high throughput format. The information and technology platforms generated and developed from this proposal will be valuable for and immediately applied to cancer biomarker discovery and validation in the future.

Project ID:PC9706-0790
External Project ID:NSC96-2320-B182-031-MY3