Luminol‐Enhanced Chemiluminescent Response of Human Melanocytes and Melanoma Cells to Hydrogen Peroxide Stress

Abstract

The response of human melanocytes and melanoma cells to hydrogen peroxide stress was measured. Cells were exposed to glucose/glucose oxidase or free H2O2 and reactive oxygen species measured by luminol‐enhanced chemiluminescence. The response was distinctly different between the two types and the addition of superoxide dismutase to melanoma cells paradoxically enhanced the chemiluminescent signal. These findings coupled with other known differences between the way these two types of cells handle oxidative stress at a molecular level suggests that a therapeutic window may be avail‐able for exploitation.

Aberrant redox regulation in human metastatic melanoma cells compared to normal melanocytes

“…In contrast, the relative amount of hydrogen peroxide in melanoma cells decreased with time while intracellular superoxide anion in melanoma cells seemed to accumulate and was 3-to 4-fold that of normal melanocytes (Table 1). We have demonstrated elsewhere that melanoma cells quench an exogenous peroxidative stress poorly and, in fact, paradoxically generate a pro-oxidant response to oxidant stress, most likely mediated by superoxide anion [16]. This oxidant stress was resisted by melanocytes and no apoptosis occurred while apoptosis was markedly increased in melanoma cells.…”

“…This finding is surprising in that most tumor cells exhibit an antioxidant phenotype [14,15]. We have also previously shown that melanocytes and melanoma cells respond differentially to exogenous peroxide with melanocytes efficiently suppressing this stress and melanoma cells unable to do so [16]; surprisingly, melanoma cells were not just unable to suppress a peroxide stress, but generated a pro-oxidant response.…”

“…5). A major feature of these studies is that we have determined the quantitative and correlative relationship between intracellular ROS and the NF-B and AP-1 system, while prior studies including our own investigations [16,4] have largely been qualitative. A limitation of these comparisons is that they have been made at only one time point; however, such comparisons require the generation of a very large amount of data.…”

New perspectives on melanoma pathogenesis and chemoprevention

“…(Meyskens et al 1997). The conclusions from our studies are summarized as follows, and illustrated in Fig.…”

Inhibition of melanogenesis by Gaillardia aristata flower extract

“…Certain ROS scavengers and inhibitors of ROS generation inhibit UV-induced melanogenesis and antioxidants like reduced glutathione (GSH) and ascorbic derivatives are applied to treat various skin problems such as depigmentation of hyperpigmented spots [5,6]. Hence, antioxidants and free radical scavengers also play an important role in protecting human skin from the harmful effects by UV radiation as hyperpigmentation [7].…”