Bipyridyl dihydrochloride inhibits tumor necrosis factor-alpha secretion by human keratinocytes on ultraviolet irradiation.
Paraquat manufacturers in Taiwan have been found to develop solar lentigo, actinic keratosis, as well as skin cancer in sun-exposed areas. Bipyridine has been found to be the responsible agent. At present, the mechanism for the pathogenesis of bipyridine-induced skin cancer is not known and it may be multifactorial. We investigated possible alterations in tumor necrosis factor (TNF)-alpha secretion in keratinocytes treated with 4,4'-bipyridyl dihydrochloride in vitro. Normal human keratinocytes were cultured and treated with bipyridine (10 micrograms/mL) or ultraviolet B (UVB) light (10 mJ/cm2), or with a combination of both. Bipyridine treatment alone resulted in a significant reduction in constitutive TNF-alpha secretion. Furthermore, in contrast to the finding in normal keratinocytes, UVB irradiation failed to promote TNF-alpha secretion in bipyridine-primed keratinocytes.
Jee
S H
SH
Department of Dermatology, National Taiwan University Hospital, Taipei, ROC.
Tsai
T F
TF
Chen
C C
CC
Sun
C C
CC
Chang
C H
CH
Chang
C C
CC
D006801:Humans; D015603:Keratinocytes / Q000187:drug effects* / Q000528:radiation effects; D008297:Male; D008928:Mitochondria / Q000187:drug effects; D011725:Pyridines / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects / Q000378:metabolism*; D014466:Ultraviolet Rays / Q000009:adverse effects*
D011725:Pyridines; D014409:Tumor Necrosis Factor-alpha; C034306:4,4'-bipyridyl