title: Bipyridyl dihydrochloride inhibits tumor necrosis factor-alpha secretion by human keratinocytes on ultraviolet irradiation.
abstract: 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.
authors.affiliation: Department of Dermatology, National Taiwan University Hospital, Taipei, ROC.
authors.forename: S H
authors.initials: SH
authors.lastname: Jee
authors.forename: T F
authors.initials: TF
authors.lastname: Tsai
authors.forename: C C
authors.initials: CC
authors.lastname: Chen
authors.forename: C C
authors.initials: CC
authors.lastname: Sun
authors.forename: C H
authors.initials: CH
authors.lastname: Chang
authors.forename: C C
authors.initials: CC
authors.lastname: Chang
mesh_terms: 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*
chemical_list: D011725:Pyridines; D014409:Tumor Necrosis Factor-alpha; C034306:4,4'-bipyridyl