Objective: To investigate the expression of glutathione peroxidase 2 (GPX2) in human lung adenocarcinoma tissues and its effect on the biological function of lung adenocarcinoma A549 cells.
Methods: The expression of GPX2 in lung adenocarcinoma and its effect on survival were analyzed by the TCGA database and the GEPIA 2 database. A total of 45 cases of primary lung adenocarcinoma tissue specimens and 45 cases of their paracancerous tissue specimens were collected, and the expression of GPX2 in the two types of tissues was detected by immunohistochemistry. Lung adenocarcinoma A549 cells were divided into the GPX2 overexpression group (GPX2), the GPX2 knockdown group (si-GPX2), the empty vector group (Vector), the siRNA negative control group (si-NC), and the WT group; the mRNA level and protein expression of GPX2 in each group of A549 cells were detected by real-time fluorescence quantitative PCR and Western blotting; the proliferation activity of each group of cells was detected by the CCK-8 assay; the effect of GPX2 on cell migration and invasion ability was detected by the scratch assay and the Transwell invasion assay; the apoptosis of each group of cells was detected by flow cytometry; Western blotting was performed to detect the expression levels of Bax, Bcl-2, E-cadherin, vimentin, and MMP2 and MMP9 proteins in each group of cells.
Results: Bioinformatics analysis showed that the expression of GPX2 was strongly correlated with the prognosis of lung adenocarcinoma patients (P < 0.01). The positive expression rates of GPX2 in lung adenocarcinoma and its paracancerous tissues were 66.0% and 15.7%, respectively (P < 0.05). The results of RT-qPCR and Western blotting showed that the expression level of GPX2 mRNA and protein in A549 cells in the GPX2 group increased, which was significantly higher than that in the WT group (P < 0.05); the expression levels of GPX2 mRNA and protein in A549 cells in the si-GPX2 group were the same, that is, significantly lower than the WT group (P < 0.05). GPX2 overexpression promoted the proliferation, migration, and invasion of A549 cells and inhibited their apoptosis; the results in the si-GPX2 group were opposite to those in the GPX2 group. Compared with the WT group, the expression of Bcl-2, vimentin, and MMP2 and MMP9 protein in the GPX2 group increased (P < 0.05), while the expression of Bax and E-cadherin protein decreased in the GPX2 group (P < 0.05); the results in the si-GPX2 group were opposite to those in the GPX2 group.
Conclusion: The expression of GPX2 in lung adenocarcinoma is related to the prognosis of patients. It is proved that GPX2 can promote the migration and invasion of lung adenocarcinoma cells and is related to the EMT/β-catenin pathway. Thus, GPX2 is expected to be an important target for the diagnosis and treatment of lung adenocarcinoma.
Copyright © 2022 Yu-peng Li et al.