Derlin-1 Is Overexpressed in Non-Small Cell Lung Cancer and Promotes Cancer Cell Invasion via EGFR-ERK-Mediated Up-Regulation of MMP-2 and MMP-9

Previous studies indicated a role of Derlin-1 in human cancers; however, its expression pattern in non-small cell Lung cancer (NSCLC) and the molecular mechanism of Derlin-1 on cancer progression have not been characterized. In the present study, Derlin-1 expression was examined in Lung cancer cell lines and human tissues. Derlin-1 overexpression correlated with pTNM stage, lymph node metastasis, and poor overall survival. siRNA knockdown of Derlin-1 impaired anchorage-dependent and anchorage-independent cell growth and invasion in A549 and H1299 cell lines, and its overexpression promoted proliferation and invasion in HBE and LTE cell lines. Derlin-1 depletion decreased matrix metalloproteinase (MMP)-2/9 at both protein and mRNA levels, with decreased MAP kinase/extracellular signal-regulated kinase (ERK)/ERK phosphorylation. Derlin-1 overexpression up-regulated MMP-2/9 expression and ERK phosphorylation, which could be reversed by MAP kinase/ERK kinase inhibitor, PD98059. The effect of Derlin-1 on MMP-2/9 up-regulation was abolished in ERK1/2 siRNA-treated cells. Further analysis showed that Derlin-1 overexpression induced EGFR phosphorylation. EGFR inhibitor blocked Derlin-1-mediated up-regulation of EGFR and ERK phosphorylation. MMP-2/9 and p-ERK up-regulation by Derlin-1 was partly blocked in EGFR-depleted cells with siRNA treatment. Immunoprecipitation confirmed the association between Derlin-1 and EGFR. In summary, our results showed that Derlin-1 is overexpressed in NSCLC and promotes invasion by EGFR-ERK-mediated up-regulation of MMP-2 and MMP-9. Derlin-1 may serve as a therapeutic target for NSCLC. (Am J Pathol 2013, 182: 954-964; http://dx.doi.org/10.1016/j.ajpath.2012.11.019)