Non-small-cell lung cancer (NSCLC) is one of the most common malignant tumors in the world. Reactive oxidative species (ROS) and nuclear factor-related factor 2 (Nrf2) -antioxidant response element (ARE) signal pathway are known to play important roles in the development of NSCLC. In this study, we identified Peroxiredoxin 5 (PRDX5) as a novel binding partner for Nrf2. PRDX5 was significantly increased in human NSCLC specimens and cell lines. Nrf2 interacted with PRDX5 in H2O2-stimulated NCSLC cells, and the interaction promoted the expression of NAD(P)H: quinone oxidoreductase 1 (NQO1) protein in NSCLC cells. Further, high expression of Nrf2 and PRDX5 were associated with worsened prognosis in patients with NSCLC significantly. Moreover, animal studies showed that the growth of tumors treated with Nrf2 and PRDX5 shRNA was significantly lower than that of the other groups. All these data indicated that overexpressed PRDX5 in NSCLC promoted binding with Nrf2 and enhanced NQO1 expression and NSCLC development. Overall, our studies demonstrated that PRDX5 can be a novel binding partner of Nrf2 in promoting NCSLC development under oxidative stress and provide potential opportunity for improving NSCLC therapy.

Deoxyribonucleic acid (DNA) epigenetic modification has been linked to specific sequences of CpG islands and plays roles in the progression of lung cancer. In this study, it was found that peroxiredoxin-5 ( PRDX5 ) was highly expressed in non-small cell lung cancer (NSCLC) tissues; however, its specific regulatory mechanisms and functions in NSCLC remain unknown. The present study therefore explored the regulatory mechanism of PRDX5 under conditions of oxidative stress (OS) in NSCLC. The results revealed that 79 of 121 NSCLC patients exhibited demethylation in the PRDX5 promoter region, which was related to the tumor, node and metastasis (TNM) stage (P=0.027). PRDX5 messenger ribonucleic acid (mRNA) expression positively correlated with the demethylation status of the promoter region. The results of bisulfite sequencing polymerase chain reaction (BSP) revealed lower demethylation frequencies in H1299 cells treated with 0 µ M H 2 O 2 , but maximum demethylation following treatment with 100 µ M H 2 O 2 . Using chromatin immunoprecipitation (ChIP) and luciferase detection assays, the effective binding of STAT3 to the transcriptional binding sites of the PRDX5 promoter region was confirmed (2 sites confirmed: Site 1, -444 to -434 bp; and site 4, -1,417 to -1,407 bp). STAT3 knockdown significantly decreased the protein expression of PRDX5 , while the overexpression of STAT3 significantly increased the protein levels of PRDX5 . When PRDX5 was overexpressed in lung cancer cells under conditions of OS, the levels of the epithelial-mesenchymal transition (EMT) biomarkers, E-cadherin and vimentin, were significantly decreased and increased, respectively. By contrast, PRDX5 knockdown resulted in significantly increased E-cadherin and decreased vimentin protein expression levels. Ultimately, when PRDX5 -small interfering RNA (siRNA) or pcDNA3.1- PRDX5 expression vector were constructed and transfected into H1299 cells pre-treated with 100 µ M H 2 O 2 , the nuclear factor (erythroid-derived 2)-like 2 ( Nrf2 ) signaling pathway was inhibited or activated. All these results suggested that the reactive oxygen species (ROS)-mediated hypomethylation of PRDX5 enhanced STAT3 binding affinity with the promoter region, and resulted in the promotion of cell migration and invasion, as well as in the activation of the Nrf2 signaling pathway in NSCLC. The demethylation status of the PRDX5 promoter may...

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Uncontrolled inflammation, featured by aggravated mobilization of Ly6Chigh inflammatory monocytes (Mos), may cause high morbidity and mortality in the pathogenesis of sepsis-associated immune disorders. Inspired by the similar membrane protein...

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