Aim: To investigate the expression of MAPK-activating death domain protein (MADD) in lung adenocarcinoma tissues and its effects on proliferation and apoptosis of lung adenocarcinoma A549 cells.
Methods: Immunohistochemistry was used to detect the expression of MADD in lung normal and tumor tissues. The expression of IG20 gene in A549 cells was measured by reverse transcription polymerase chain reaction. A549 cells were transfected with pEYFP-MADD plasmids carrying MADD gene or pNL-SIN-GFP-MID lentiviral vectors used for RNA interference. MADD expression and cell proliferation and apoptosis were determined by Western blot, MTT assay, and flow cytometry.
Results: The expression levels of MADD were higher in lung adenocarcinoma and squamous cell carcinoma tissues than that in lung normal tissues, and lung adenocarcinoma tissues expressed more MADD than lung squamous cell carcinoma tissues. The transcript encoding MADD was expressed in A549 cells. The transfection of pEYFP-MADD plasmids could increase MADD expression and cell proliferation of A549 cells, while the A549 cells transfected with pNL-SIN-GFP-MID lentiviral vectors showed significantly decreases in the MADD level and proliferation. It is shown that MADD overexpression could inhibit A549 cell apoptosis, and knock down of MADD could promote apoptosis of them.
Conclusion: The expression of MADD increases obviously in lung adenocarcinoma, and MADD can promote survival of lung adenocarcinoma cells by inhibiting apoptosis.