Mice deficient in tumor necrosis factor-alpha are resistant to skin carcinogenesis.
Given the associations between chronic inflammation and epithelial cancer, we studied susceptibility to skin carcinogenesis in mice deficient for the pro-inflammatory cytokine TNF-alpha (refs. 5,6). TNF-alpha(-/-) mice were resistant to development of benign and malignant skin tumors, whether induced by initiation with DMBA and promotion with TPA or by repeated dosing with DMBA. TNF-alpha(-/-) mice developed 5-10% the number of tumors developed by wild-type mice during initiation/promotion and 25% of those in wild-type mice after repeated carcinogen treatment. TNF-alpha could influence tumor and stromal cells during tumor development. The early stages of TPA promotion are characterized by keratinocyte hyperproliferation and inflammation. These were diminished in TNF-alpha(-/-) mice. TNF-alpha was extensively induced in the epidermis, but not the dermis, in TPA-treated wild-type skin, indicating that dermal inflammation is controlled by keratinocyte TNF-alpha production. Deletion of a TNF-alpha inducible chemokine also conferred some resistance to skin tumor development. TNF-alpha has little influence on later stages of carcinogenesis, as tumors in wild-type and TNF-alpha(-/-) mice had similar rates of malignant progression. These data provide evidence that a pro-inflammatory cytokine is required for de novo carcinogenesis and that TNF-alpha is important to the early stages of tumor promotion. Strategies that neutralize TNF-alpha production may be useful in cancer treatment and prevention.
Biological Therapy Laboratory, Imperial Cancer Research Fund, London, UK.
R J
RJ
Moore
D M
DM
Owens
G
G
Stamp
C
C
Arnott
F
F
Burke
N
N
East
H
H
Holdsworth
L
L
Turner
B
B
Rollins
M
M
Pasparakis
G
G
Kollias
F
F
Balkwill
D015127:9,10-Dimethyl-1,2-benzanthracene / Q000633:toxicity; D000818:Animals; D003433:Crosses, Genetic; D005260:Female; D007113:Immunity, Innate / Q000235:genetics*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D012867:Skin / Q000187:drug effects / Q000473:pathology; D012878:Skin Neoplasms / Q000139:chemically induced / Q000276:immunology* / Q000473:pathology; D013755:Tetradecanoylphorbol Acetate / Q000633:toxicity; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000172:deficiency* / Q000235:genetics / Q000502:physiology
D014409:Tumor Necrosis Factor-alpha; D015127:9,10-Dimethyl-1,2-benzanthracene; D013755:Tetradecanoylphorbol Acetate