A Significance of MMP-1 in EGFR-TKI Resistant Lung Adenocarcinoma: A Potential of Therapeutic Target

Lung adenocarcinoma with EGFR-TKI (epidermal growth factor receptor-tyrosine kinase inhibitor) resistance was reported to harbor higher ability of invasion and migration than those sensitive to EGFR-TKI, but the function of MMPs (matrix metalloproteinases) has not been explored in EGFR-TKI resistant lung adenocarcinoma. In this study, the correlation between immunohistochemical status of MMP-1 and clinicopathological factors were analyzed in 89 lung adenocarcinoma. We performed microarray, migration assay and invasion assay using EGFR-TKI sensitive cell lines and EGFR-TKI resistant cell lines. To clarify the mechanism of MMP-1 induction, we treated lung adenocarcinoma cells with EGF and rapamycin, performed phosphorylation antibody array and analyzed the correlation between MMP-1 expression and EGFR or mTOR (mammalian target of rapamycin) pathway. As a result, we firstly demonstrated that MMP-1 played an important role in migration and invasion abilities of EGFR-TKI resistant lung adenocarcinoma, and that mTOR pathway could be associated with an induction of MMP-1. We demonstrated the significant positive correlation between MMP-1 status in lung adenocarcinoma cells and the history of smoking, and the subtype of invasive mucinous adenocarcinoma. In conclusion, This study provides insights into the development of a possible alternative therapy manipulating MMP-1 and mTOR signaling pathway in EGFR-TKI resistant lung adenocarcinoma.