Effect of JAG2 on migration and invasion in colorectal cancer cell by PRAF2, independent of epithelial-mesenchymal transition.

Abstract

e15107 Background: Our previous studies revealed the increased expression of Jagged 2 (JAG2) in most intestinal cancer tissues. In colon cancer cell lines, JAG2 involved in the regulation of migration and invasion without affecting cell proliferation. This study further explored the mechanisms of how JAG2 promotes migration and invasion of colorectal cancer cells. Methods: We analyzed the expression of JAG2 mRNA and protein in normal human colon tissue cells and colorectal cancer cells. The promotive role of JAG2 in migration and invasion was tested by JAG2 siRNA and JAG2 overexpression in various colon cancer cell lines. To understand the mechanisms, we first treated HT29 cells with LY2157299, a TGF-β signaling pathway inhibitor, and Slug siRNA, to identify the cross-talk between JAG2 and EMT pathway. In addition, co-expression status of JAG2 and TGF-β-induced epithelial-mesenchymal transition (EMT) markers was analyzed. Finally, by using siRNA and proteomics technology, co-expressed proteins of JAG2 in colorectal cancer cells were identified. Results: JAG2 was abnormally expressed in colorectal cancer tissues and directly related with clinical stages. Similar to the findings in human tissues, the expression of both JAG2 mRNA and protein was significantly increased in the colorectal cancer cell lines compared with that of normal colorectal cell line CCD18-Co. Interestingly, the promotion of JAG2 in migration and invasion was independent of EMT pathway. Furthermore, we found that the expression of JAG2 was correlated with PRAF2 (PRA1 Domain Family Member 2), a protein involved in the formation of exosome-like vesicles. In the presence of PRAF2, JAG2-rich exosome promoted migration and invasion. JAG2 might regulate the migration and invasion of colon cell through PRAF2. Conclusions: This is the evidence supporting the biological function of JAG2 in migration and invasion through non-EMT-dependent pathways and also the first exploration of the role of PRAF2 in colorectal cancer cells. These findings provide the theoretical basis for potential targeted therapy against JAG2/PRAF2.