Abstract
Micro-Western Array (MWA) is an antibody-based modified reverse phase array composes of a GeSim Nanoplotter arrayer, a GE multiphor, and a Licor Odyssey scanner. MWA allows detecting protein expression level or phosphorylation status change of 96-384 different antibodies in 6-15 samples simultaneously. It has been shown to be effective in characterizing the protein profile or signaling network in cell systems. We used MWA to assay the protein expression profile in normal human like prostate epithelial cell lines (RWPE-1, PZ-HPV-7) vs. malignant human prostate cancer (PCa) cell lines (LNCaP 104-S, LNCaP 104-R1, PC-3, DU-145, CA-HPV-10) with 708 antibodies detecting important signaling proteins in cells. According to our study, we found 28 proteins differently expressed in cancerous PCa cells as compared to normal prostate cells. Four of the proteins, the PAK2, PICK1, TEC, and COX1 showed significantly different between normal and cancer PCa cells and were rarely studied previously. We focused on examining the role of cyclooxygenase-1 (COX-1) in PCa cells. Protein level of COX1 in normal cell line is much higher than in PCa cell line. Cyclooxygenase (COX) is the central enzyme in the biosynthetic pathway to generate prostaglandins from arachidonic acid. We discovered that overexpression of COX-1 suppressed the cell proliferation, migration, and invasion of PCa cells. These observations indicated the possibility that COX-1 may be involved in the regulation of tumor growth and metastasis of PCa, possibly via regulation of inflammation pathways. We believe that our protein profiling database will be useful for drug discovery and signaling network study in PCa research.