Background & objective: Recent studies have shown that activation of nuclear factor-kappaB(NF-kappaB) can regulate the invasion and metastasis of cancer cells. The present study was to investigate inhibition of NF-kappaB activity on invasion of human lung cancer cell line A549 and the possible mechanism.
Methods: The recombinant plasmid pcDNA3.1(+)/IkappaBalpha, expressing the alpha isoform (IkappaBalpha) of the NF-kappaB inhibitor, was constructed. A549 cells were cultured in vitro and divided into non-transfection group, pcDNA3.1(+) transfected group and pcDNA3.1(+)/IkappaBalpha transfected group. The expression of IkappaBalpha was detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. The activity of NF-kappaB was determined by electrophoretic mobility shift assay (EMSA). Invasion of A549 cells was assessed by transwell chamber assay. The expression of MMP-2 and MMP-9 was detected by RT-PCR and gelatin zymography.
Results: Plasmid pcDNA3.1(+)/IkappaBalpha was successfully constructed and expressed in A549 cells. The activity of NF-kappaB, the number of invasive cells, the activity of MMP-2 and MMP-9 of A549 cells in pcDNA3.1(+)/IkappaBalpha transfected group were significantly lower than those in non-transfection group and pcDNA3.1(+) transfected group (all P<0.05).
Conclusion: Transfection of IkappaBalpha can inhibit NF-kappaB activity, thus inhibit cell invasion of A549, which may be through the down-regulation of MMP-2 and MMP-9 expressions.