TNF-alpha drives matrix metalloproteinase-9 in squamous oral carcinogenesis.
OBJECTIVE
It is well known that invasion is a seminal event in the progression of oral and other head and neck carcinoma sites. We have previously demonstrated tumor necrosis factor (TNF)-alpha and its dependent cytokines are upregulated in saliva during oral carcinogenesis. TNF-dependent events stimulate nuclear factor (NF)-kappaB and many NF-kappaB-dependent genes are associated with cancer progression.


METHODS
In the present study, we examined NF-kappaB stimulation of matrix metalloproteinase (MMP)-9 in a precancerous keratinocyte cell line that models leukoplakia (Rhek cells). We stimulated Rhek cells with both TNF-alpha and phorbol myristate acetate, known stimulants of NF-kappaB. We then assayed MMP-9 transcription and secretion by luciferase reporter genes, quantitative real-time polymerase chain reaction, and fluorometric enzyme-linked immunosorbent serologic assay.


RESULTS
We discovered that the MMP-9 promoter was significantly stimulated by phorbol myristate acetate and TNF-alpha on luciferase reporter gene assays. Further, we uncovered that functional MMP-9 promoter activation was accompanied by significant increases in MMP-9 gene expression, as judged by quantitative real-time polymerase chain reaction. Functional activation of the MMP-9 protein was stimulated by TNF-alpha and PMA on a fluorescent enzyme-linked immunosorbent serologic assay. Finally, we searched our salivary proteomic database for increases in MMP-9 and discovered it was the third most significant protein in salivas of oral cavity cancer patients over normal controls.


CONCLUSIONS
We conclude the milieu cytokine, TNF-alpha, has the capacity to provide stimulation of events related to early invasion of oral cavity cancer, as judged by its ability to stimulate MMP-9.
Hohberger
Laurie
L
Molecular Oncology Program, Department of Otolaryngology, University of Minnesota, Minneapolis, Minnesota, USA.
Wuertz
Beverly R K
BR
Xie
Hongwei
H
Griffin
Tim
T
Ondrey
Frank
F
D045744:Cell Line, Tumor; D018450:Disease Progression; D004789:Enzyme Activation; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism*; D009062:Mouth Neoplasms / Q000378:metabolism*; D009361:Neoplasm Invasiveness / Q000503:physiopathology*; D018307:Neoplasms, Squamous Cell / Q000378:metabolism*; D011230:Precancerous Conditions / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012463:Saliva / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000378:metabolism / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D015854:Up-Regulation
D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D020780:Matrix Metalloproteinase 9; D013755:Tetradecanoylphorbol Acetate