Inorganic arsenic is considered a human carcinogen based principally on epidemiological
evidence. Unlike most initiating chemicals, arsenic is inactive or extremely weak in its ability
to directly induce gene mutations. Arsenite has been shown, however, to enhance
mutagenicity when present with other agents such as UV radiation. Synergistic potentiation
of chromosomal damage has been shown with co-treatment with DNA-crosslinking agents.
Arsenite at low concentrations is known to be highly selective in reacting with closely space …

Arsenic enhances skin tumor formation when combined with other carcinogens, including
UV radiation (UVR). In this study we report that low micromolar concentrations of arsenite
synergistically increases UVR-induced oxidative DNA damage in human keratinocytes as
detected by 8-hydroxyl-2′-deoxyguanine (8-OHdG) formation. Poly (ADP-ribose)
polymerase-1 (PARP-1) is involved in base excision repair, a process that repairs 8-OHdG
lesions. Arsenite suppresses UVR-induced PARP-1 activation in a concentration-dependent …