E. Corsini et al., IN-VITRO MECHANISM(S) OF ULTRAVIOLET-INDUCED TUMOR-NECROSIS-FACTOR-ALPHA RELEASE IN A HUMAN KERATINOCYTE CELL-LINE, Photodermatology, photoimmunology & photomedicine, 11(3), 1995, pp. 112-118
It has been demonstrated that ultraviolet (UV) irradiation is able to
induce both in vivo and in vitro, tumor necrosis factor-alpha (TNF) re
lease. The purpose of the present study was to evaluate, using a human
keratinocyte cell line NCTC 2544, the mechanism(s) of UV-induced TNF
release and the ability of commonly used sunscreens to modulate UV-ind
uced TNF release. TNF release can be partially prevented both by addin
g an anti-human IL-1 alpha antibody after irradiation, suggesting an a
utocrine effect of IL-1 alpha in inducing TNF release, and by adding a
ntioxidants indicating also a role of oxidant species. TPCK, a I kappa
-B alpha protease inhibitor, was able to virtually abolish UV-induced
TNF release, indicating that UV-induced TNF release requires NF-kappa
B activation. Anti-human IL-1 beta antibody was ineffective as expecte
d, considering that keratinocytes are unable to process pre-IL-1 beta
to its active form. To evaluate the sunscreen's modulation on UV-induc
ed TNF release, confluent cells were irradiated, in the presence or ab
sence of the tested sunscreens (Uvinul MS40, Uvinul P25 and Uvinul DS4
9). Different IC50 values could be calculated, which may be related to
different UV absorption spectrums: Uvinul MS40 offers great protectio
n by virtue of its broader absorption spectrum, closely followed by Uv
inul P25 and finally by Uvinul DS49.