Lung tumor growth-promoting function of peroxiredoxin 6

• Published in: Free radical biology & medicine 2013-08, Vol.61, p.453-463
• Main Authors: Jo, Miran, Yun, Hyung-Mun, Park, Kyung-Ran, Hee Park, Mi, Myoung Kim, Tae, Ho Pak, Jhang, Jae Lee, Soo, Moon, Dong Cheul, Park, Chun-Woong, Song, Sukgil, Lee, Chong-Kil, Bae Han, Sang, Tae Hong, Jin
• Format: Article
• Language: English
• Subjects: Animals; AP-1; apoptosis; caspase-3; cell growth; Cell Line, Tumor; Cell Proliferation; cyclin-dependent kinase; cyclins; DNA; DNA - metabolism; Free radicals; gene overexpression; genetically modified organisms; glutathione peroxidase; Glutathione Peroxidase - analysis; Humans; JNK Mitogen-Activated Protein Kinases - metabolism; lung neoplasms; Lung Neoplasms - pathology; MAPK; messenger RNA; Mice; Mice, Inbred C57BL; mitogen-activated protein kinase; peroxiredoxin; Peroxiredoxin 6; Peroxiredoxin VI - analysis; Peroxiredoxin VI - physiology; Phospholipases A2 - metabolism; proliferating cell nuclear antigen; small interfering RNA; Transcription Factor AP-1 - metabolism; vascular endothelial growth factors
• ISSN: 0891-5849; 1873-4596
• DOI: 10.1016/j.freeradbiomed.2013.04.032

This study compared lung tumor growth in PRDX6-overexpressing transgenic (Tg) mice and normal mice. These mice expressed elevated levels of PRDX6 mRNA and protein in multiple tissues. In vivo, Tg mice displayed a greater increase in the growth of lung tumor compared with normal mice. Glutathione peroxidase and calcium-independent phospholipase 2 (iPLA2) activities in tumor tissues of Tg mice were much higher than in tumor tissues of normal mice. Higher tumor growth in PRDX6-overexpressing Tg mice was associated with an increase in activating protein-1 (AP-1) DNA-binding activity. Moreover, expression of proliferating cell nuclear antigen, Ki67, vascular endothelial growth factor, c-Jun, c-Fos, metalloproteinase-9, cyclin-dependent kinases, and cyclins was much higher in the tumor tissues of PRDX6-overexpressing Tg mice than in tumor tissues of normal mice. However, the expression of apoptotic regulatory proteins including caspase-3 and Bax was slightly less in the tumor tissues of normal mice. In tumor tissues of PRDX6-overexpressing Tg mice, activation of mitogen-activated protein kinases (MAPKs) was much higher than in normal mice. In cultured lung cancer cells, PRDX6 siRNA suppressed glutathione peroxidase and iPLA2 activities and cancer cell growth, but the enforced overexpression of PRDX6 increased cancer cell growth associated with their increased activities. In vitro, among the tested MAPK inhibitors, c-Jun NH2-terminal kinase (JNK) inhibitor clearly suppressed the growth of lung cancer cells and AP-1 DNA binding, glutathione peroxidase activity, and iPLA2 activity in normal and PRDX6-overexpressing lung cancer cells. These data indicate that overexpression of PRDX6 promotes lung tumor growth via increased glutathione peroxidase and iPLA2 activities through the upregulation of the AP-1 and JNK pathways. [Display omitted] •Lung tumor growth is higher in PRDX6-Tg mice compared to normal mice.•PRDX6 promotes lung tumor growth by increasing GPx and iPLA2 activities.•Activation of AP-1 and JNK pathways is critical for PRDX6-induced lung tumor growth.