JNK/AP-1 pathway is involved in tumor necrosis factor-alpha induced expression of vascular endothelial growth factor in MCF7 cells.
Vascular endothelial growth factor (VEGF) has been implicated in breast tumor angiogenesis. And tumor necrosis factor-alpha (TNF-alpha) is a positive regulator of VEGF. This study was aimed to identify the signalling pathway of TNF-alpha in VEGF expression regulation in breast cancer cell line MCF7. Using luciferase reporter assays, we demonstrated that TNF-alpha significantly increased activator protein-1 (AP-1) transcriptional activity in the MCF7 cells. The expression of the AP-1 family members c-Jun, c-Fos and JunB and phosphorylation levels of c-Jun were upregulated by TNF-alpha, whereas other AP-1 family members Fra-1, Fra-2, and JunD were unaffected. The activation of AP-1 was associated with the formation of p-c-Jun-c-Jun and p-c-Jun-JunB homodimers. Furthermore, the phosphorylation levels of c-Jun N-terminal kinase (JNK) but not P38 and ERK were elevated by TNF-alpha in MCF7 cells. TNF-alpha potently upregulated the mRNA and protein levels of VEGF, which were significantly reversed by JNK inhibitor SP600125. Finally using chromatin immunoprecipitation (CHIP) assays, we found that p-c-Jun bound to the VEGF promoter and regulated VEGF transcription directly. These data suggest that the pro-inflammatory cytokine TNF-alpha is a critical regulator of VEGF expression in breast cancer cells, at least partially via a JNK and AP-1 dependent pathway.
Yin
Yongmei
Y
Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, People's Republic of China.
Wang
Shui
S
Sun
Yujie
Y
Matt
Young
Y
Colburn
Nancy H
NH
Shu
Yongqian
Y
Han
Xiao
X
D000873:Anthracenes / Q000494:pharmacology; D001943:Breast Neoplasms / Q000235:genetics*; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism* / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics*
D000873:Anthracenes; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; D042461:Vascular Endothelial Growth Factor A; C432165:pyrazolanthrone; D048031:JNK Mitogen-Activated Protein Kinases