N-myc downstream regulated gene ۲ overexpression reduces matrix metalloproteinase-۲ and -۹ activities and cell invasion of A۵۴۹ lung cancer cell line in vitro

Objective(s):N-myc downstream regulated gene ۲ (NDRG۲) is a candidate gene for tumor suppression. The expression of NDRG۲ is down-regulated in several tumors including lung cancer. The aim of this study was to explore the effect of NDRG۲ overexpression on invasion, migration, and enzymatic activity of matrix metalloproteinase-۲ (MMP-۲) and -۹ (MMP-۹) in human lung adenocarcinoma A۵۴۹ cells.  Materials and Methods: A recombinant plasmid encoding green fluorescent protein (GFP)-tagged NDRG۲ (pCMV۶-AC-NDRG۲-GFP) was used to overexpress GFP-tagged NDRG۲ in A۵۴۹ cells. The cells in the experimental group and those in the control group were transfected with pCMV۶-AC-NDRG۲-GFP and a control plasmid without NDRG۲ (pCMV۶-AC-GFP), respectively. Fluorescent microscopy and flowcytometry analysis of GFP expression were used to evaluate the cellular expression of GFP-tagged NDRG۲ and the efficiency of transfection. The effects of NDRG۲ expression on cell invasion and migration were evaluated using transwell filter migration assay. The gelatinase activity of secreted MMP-۲ and MMP-۹ was measured by gelatin zymography. Results:Our results demonstrated the expression of GFP-tagged NDRG۲ in the cytoplasm and nucleus of A۵۴۹ cells. The findings of transwell assay showed that NDRG۲ overexpression reduced migration and invasion of A۵۴۹ cells compared to control cells. Gelatin zymography analyses revealed that NDRG۲ overexpression decreased the gelatinase activity of secreted MMP-۲ and MMP-۹. Conclusion: These findings suggest that NDRG۲ may be a new anti-invasion factor in lung cancer that inhibits MMPs activities.

Keywords:

Invasion , Lung cancer , Matrix metalloproteinase , Migration , N-myc downstream-regulated gene ۲