A two-way effect of MnSOD overexpression on proliferation of esophageal cancer cell line TE-1 and xengograft tumor growth / 肿瘤

ABSTRACT

Objective: To explore the effect of manganese superoxide dismutase (MnSOD) overexpression on the proliferation of esophageal cancer cell line TE-1 in vivo and in vitro . Methods: TE-1 cells were transfected with a plasmid binding MnSOD cDNA, and then TE-1Mm cells (with moderate expression of MnSOD) and TE-1Mh cells (with high expression of MnSOD) were established. RT-PCR and Western blotting were used to detect the mRNA and protein expressions of target MnSOD gene in both of TE-1Mm and TE-1Mh cells, respectively. The ability of cell proliferation and apoptosis and the cell cycle distribution were examined by plate colony-forming test and flow cytometry (FCM). The xenograft tumor models in nude mice were established. The effect of MnSOD overexpression on cell proliferation was evaluated in vivo , and the expression of MnSOD protein in xenograft tumors was detected by immunohistochemistry and Western blotting. Results: TE-1 cells with different expression levels of MnSOD proteins were established by transfection with different amounts of plasmids binding MnSOD cDNA. The colony-formation rates of TE-1Mm and TE-1Mh cells were (23.0±2.7)% and (45.3±4.5)%, respectively, which were both significantly higher than those in TE-1 cells (34.7±4.2)% and TE-1n cells (33.7±4.7)%, P<0.05. The apoptosis rate of TE-1Mm (10.6±1.0)% was significantly higher than those in TE-1 cells (34.7±4.2)% and TE-1n cells (33.7±4.7)%, and the apoptosis rate of TE-1Mh (10.6±1.0)% was significantly lower than those in TE-1 cells and TE-1n cells (P<0.05). FCM revealed that the percentage of TE-1Mh cells was decreased in G 0/G1 phase and increased in G2/M and S phases, while the percentage of TE-1Mm cells was increased in G0/G 1 phase and decreased in G2/M and S phases induced by MnSOD overexpression. The growth of xenograft tumors was inhibited in TE-1Mm cell-implanted group, while which was improved in TE-1Mh cell-implanted group. The expressions of MnSOD protein in TE-1Mm and TE-1Mh cells were significantly higher than those in TE-1 and TE-1n cells (P<0.05). Conclusion: MnSOD overexpression exerts a two-way effect involving inhibition or promotion on the proliferation of TE-1 cells in vivo and in vitro.