CD26/dipeptidyl peptidase IV contributes to tumor metastasis in human lung adenocarcinoma

Abstract

CD26/dipeptidyl peptidase IV (DPPIV) is a 110-kDa trans-membrane ectoenzyme that has multiple functions in humans. Previously, we established a highly metastatic human lung adenocarcinoma cell line exhibiting epithelialmesenchymal transition (EMT) by in vivo selection in NOD/SCID mice and performed microarray analysis; we showed that CD26 expression was higher in SPC-A-1sci cells compared to SPC-A-1 parent cells. The effect of CD26 overexpression in lung adenocarcinoma is unclear. In the current study, through Matrigel invasion and metastasis assays and Western blotting assay, we found that CD26 regulated the invasion and metastasis of lung adenocarcinoma cells and that the expression of CD26 correlated with the expression of proteins involved in EMT. The results from human lung adenocarcinoma tissue microarrays showed that CD26 was highly expressed in poorly differentiated lung adenocarcinomas compared to highly differentiated cancers. These results suggest that CD26 has a tumor-promoting function and is a putative prognostic marker for lung adenocarcinoma in patients.