Role of oxidative stress and the antioxidant network in cutaneous carcinogenesis

Abstract

Melanoma and nonmelanoma skin cancers are among the most prevalent cancers in the human population. Solar ultraviolet radiation is considered a major etiological factor but the relationship between dose, timing, and nature of exposure to tumor development is still unclear. Free radicals are generated by normal physiologic processes, including aerobic metabolism and inflammatory response, but may inflict cellular damage when generation is increased and antioxidant defense mechanisms are overwhelmed. Important findings supporting the free radical hypothesis in skin carcinogenesis are: (1) Reactive oxygen species (ROS) are generated in UVA- and UVB-irradiated skin in excessive doses, (2) the natural cutaneous antioxidant defense is impaired upon UV-exposure, (3) free radicals are involved in all steps of carcinogenesis, (4) supplementation with antioxidants can inhibit skin carcinogenesis, and (5) conditions that increase ROS generation enhance photocarcinogenesis. These findings provide a promising rationale for the development of powerful new antioxidant strategies in the prevention and therapy of skin cancer.

Raman spectroscopic mapping for the analysis of solar radiation induced skin damage

“…Solar UV radiation is also known to induce cellular and genomic toxicity, reactive oxygen species (ROS) formation, DNA damage, sunburnt cells and higher proteolytic rates [36][37][38][39][40][41][42][43] . If the cellular repair and antioxidant responses to UV radiation are overwhelmed, cellular photodamage can occur and may initiate photocarcinogenesis [44][45][46] . One of the most serious effects of UV is DNA mutagenesis [47][48][49] .…”

Environmental exposure to trace elements and risk of cutaneous melanoma

“…Our findings concerning Cu, when exposure was categorized into two categories, must be evaluated with caution, also considering that there was limited evidence of a linear association between toenail levels and disease risk. Despite these caveats, in view of the established ability of Cu to induce oxidative stress, a possible pathogenetic mechanism of melanoma (Farmer et al, 2003;Sander et al, 2004), an association between excess Cu exposure and melanoma risk should also be considered to explain our findings. Our findings might also be explained by an abnormal metabolism of this element, since in melanoma patients it has been described as an abnormal expression of metallothioneins, ubiquitous proteins with high affinity for metals such as Cu, whose higher concentrations might increase body content of this element (Weinlich et al, 2003).…”

Guava: phytochemical composition of a potential source of antioxidants for cosmetic and/or dermatological applications

“…The main advantage of the topical administration when compared to the oral administration to treat and prevent skin conditions is the direct delivery of bioactive substances to the target area, thus eliminating concerns about systemic circulation Page 2 / 10 (Meinke et al, 2010;Palombo et al, 2007). The cutaneous delivery of antioxidants is a complementary and well known treatment to prevent skin aging and to avoid dermal diseases, such as skin cancer (Sander et al, 2004;Pinnell, 2003;Dreher et al, 1998;Lopez-Torres et al, 1998). Pinnell (2003) explains that antioxidants are an important alternative to protect the skin from photodamage, and should be associated with sunscreens.…”

“…These substances are likely to be effective in the reduction of the stroke and cancer incidence, already attributed to the consumption of fruits and vegetables (Beecher, 1999). They act mainly preventing the oxidative cell damage caused by the inactivation of free radicals generated by the metabolism, inflammatory processes, environmental conditions, UV radiation etc (Dhalla, Temsah, Netticadan, 2000;Sander et al, 2004). Considering the importance of antioxidants in the human body, the regular consumption of significant amounts of fruits and vegetables has been promoted by specialists to prevent degenerative and chronic diseases (Jiménez-Escrig et al, 2001).…”