Plumbagin inhibits invasion and migration of liver cancer HepG2 cells by decreasing productions of matrix metalloproteinase‐2 and urokinase‐ plasminogen activator

Abstract

To investigate the inhibitory effects of plumbagin (5-hydroxy-2 methyl-1,4-naphthoquinone) on the invasion and migration and its correlation with matrix metalloproteinase-2 (MMP-2) and urokinase-plasminogen activator (u-PA) in liver cancer HepG2 cells under non-cytotoxic concentrations. The cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The adhesion, migration and invasion were measured by cell-matrix adhesion assay and Boyden chamber assay. The MMP-2 and u-PA activities were estimated by gelatin and casein-plasminogen zymography. The mRNA and protein levels of MMP-2, u-PA, urokinase-plasminogen activator receptor (u-PAR), tissue inhibitor of metalloproteinase-2 (TIMP-2), plasminogen activator inhibitor-1 (PAI-1), nuclear factor kappa B (NF-kappaB), c-Fos and c-Jun were evaluated by semi-quantitative reverse transcription polymerase chain reaction and western blotting. Also, the binding abilities of NF-kappaB and activator protein-1 (AP-1) were analyzed by electrophoretic mobility shift assay (EMSA). In this study, plumbagin had exhibited an inhibitory effect on the abilities of adhesion, migration and invasion. The results from zymography showed plumbagin treatment may decrease the activities of MMP-2 and u-PA. Further, the mRNA and protein levels of MMP-2, u-PA and u-PAR were significantly reduced, while TIMP-2 and PAI-1 were elevated by plumbagin treatment. Next, plumbagin significantly decreased the nuclear levels of NF-kappaB, c-Fos and c-Jun. Also, treating HepG2 cells with plumbagin leads to dose-dependent inhibition on the binding abilities of NF-kappaB and AP-1. We demonstrated the inhibitory effects of plumbagin on the invasion, migration and adhesion of HepG2 cells, while plumbagin treatment may decrease the expressions of MMP-2 and u-PA and enhance the expressions of TIMP-2 and PAI-1.