BACKGROUNDRecent studies have shown that NS-398, a highly selective COX-2 inhibitor, can enhance the inhibition effects of cisplatin on adenocarcinoma cell proliferation, but the mechanism is still unknown. The aim of this study is to explore the mechanism about the synergistic effects of NS-398 and cisplatin to human lung adenocarcinoma cell line.

METHODSDifferentially expressed proteins were separated in human lung adenocarcinoma cells treated with NS-398 and/or cisplatin by immobilized pH gradient-based two-dimensional gel electrophoresis (2-DE), then 19 out of obtained proteins were identified by peptide mass fingerprint (PMF) based on matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) and database searching.

RESULTSThere were 22 down-regulated proteins and 2 up-regulated proteins in NS-398+cisplatin combination group compared with control groups. Finally six proteins were identified, in which some were cytokeratins, some were associated with proliferation and apoptosis, and the others were involved in metabolism of tumor cells.

CONCLUSIONSThe down-regulation of HSP90 and triosephosphate isomerase may be related to the synergistic effects of NS-398 and cisplatin on human lung adenocarcinoma cells.