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Cutaneous melanoma is least common (only about 1% of skin cancers) but is the deadliest malignant tumor. Moreover, amelanotic types of melanoma are very difficult for clinical diagnosis. The standard therapy can cause a lot of side effects, e.g., nausea, vomiting, and headaches, which means that novel and effective strategies are required. Interestingly, phenothiazine derivatives possess sedative, antiemetic, and anticancer activity. Our goal was to determine the effect of perphenazine and prochlorperazine on cell viability, motility, microphthalmia-associated transcription factor (MITF) and tyrosinase content in melanotic and amelanotic melanoma cells. The viability of C32 and COLO829 melanoma cells was evaluated by the WST-1 colorimetric assay; impact on motility of human melanoma was performed by wound-healing assay, while tyrosinase and MITF content were determined by Western blot. In the present study, we explore the anticancer effect of perphenazine and prochlorperazine in human melanotic (COLO829) and amelanotic (C32) melanoma cells concluding that prochlorperazine inhibits cell viability in a concentration-dependent manner, impairs motility, and decreases tyrosinase and MITF amounts. Moreover, the analyzed drugs decrease/increase MITF amount depending on the type of melanoma. We demonstrated that the decrease of MITF and tyrosinase protein induces motility inhibition of C32 cells, which suggests the ability of those drugs to restore cancer cell sensitivity to treatment. The ability of prochlorperazine to contain the spread of the amelanotic melanoma in vivo may be helpful in the development of a new and effective antimelanoma therapies.

Purpose Fluphenazine and prochlorperazine as phenothiazine-class antipsychotic drugs are widely used to treat schizophrenia, however their use is associated with significant side effects such as extrapyramidal symptoms, as well as ocular and skin disorders. Our goal was to determine the effect of fluphenazine and prochlorperazine on cell viability and melanogenesis in lightly pigmented normal human melanocytes. Methods The viability of melanocytes was evaluated by the WST-1 colorimetric assay, while melanin content and tyrosinase activity were tested spectrophotometrically. Results It has been shown that both phenothiazines induce the concentration-dependent loss in cell viability. The EC50 values were calculated to be 6.13 and 0.63 μM for fluphenazine and prochlorperazine, respectively. Fluphenazine in the concentration of 5.0 μM and prochlorperazine in concentrations of 0.5 and 0.75 μM decreased melanin content and tyrosinase activity. The observed inhibition of melanogenesis may be explained by the decrease of enzyme activity. Conclusions The demonstrated changes in melanization process in lightly pigmented cells exposed to fluphenazine and prochlorperazine in vitro suggest a significant role of melanin and melanocytes in the mechanisms of undesirable side effects of these drugs in vivo. Graphical abstractFluphenazine and prochlorperazine significantly inhibits melanogenesis in lightly pigmented melanocytes HEMn-LP.

Nicotine is a main compound of tobacco plants and may affect more than a billion people all over the world that are permanently exposed to nicotine from cigarettes, various forms of smoking cessation therapies, electronic cigarettes or second-hand smoke. It is known that nicotine forms complexes with melanin what may lead to accumulation of this alkaloid in tissues of living organisms containing the pigment. This may affect the viability of cells and process of melanin biosynthesis that takes place in melanocytes. Although UV radiation is known to be a particular inductor of melanin biosynthesis, its simultaneous effect with nicotine on this process as well as the viability of human cells containing melanin have not been assessed so far. The aim of this study was to examine the simultaneous impact of nicotine and UV radiation on viability and melanogenesis in cultured normal human melanocytes dark (HEMn-DP) and light (HEMn-LP) pigmented. Nicotine together with UV radiation induced concentration-dependent loss in melanocytes viability. The higher cell loss was observed in dark pigmented melanocytes in comparison to light pigmented cells. Simultaneous exposure of cells to nicotine and UV radiation also caused changes in melanization process in both tested cell lines. The data suggest that simultaneous exposure of melanocytes to nicotine and UV radiation up-regulates melanogenesis and affects cell viability. Observed processes are more pronounced in dark pigmented cells.

E-cigarettes are used by millions of people despite the fact that the harmful effect of aerosol emitted from these products to the human organism is still not clear. In this paper, toxicity of vapor generated using different solutions and battery output voltage on A549 cells viability is presented. The obtained EC

Chlorpromazine is used in the treatment of schizophrenia and psychotic disorders and belongs to phenothiazine class of neuroleptic drugs. It shows severe side effects such as extrapyramidal symptoms as well as ocular and skin disorders, but the mechanism is still not fully established. The aim of this study was to examine the effect of chlorpromazine on cell viability, melanogenesis and antioxidant defense system in normal human melanocytes. It has been demonstrated that chlorpromazine induces concentration dependent loss in cell viability. The value of EC(50) was calculated to be 2.53 μM. Chlorpromazine in lower concentrations (0.0001, 0.001 and 0.01 μM) increased the melanin and microphthalmia-associated transcription factor (MITF) content and tyrosinase activity, while changes of antioxidant enzymes activity were not observed. It suggests that long-term chlorpromazine therapy, even with low drug doses, may lead to hyperpigmentation disorders in skin and/or eye. The use of the analyzed drug in higher concentrations (0.1 and 1.0 μM) caused significant alterations of antioxidant enzymes activity in normal melanocytes, what may explain a potential role of chlorpromazine in the depletion of cellular antioxidant status leading to other adverse effects associated with the high-dose and/or long-term therapy.

Oxytetracycline is a broad-spectrum antibiotic, used in dermatology and veterinary medicine. Like other tetracyclines, it may evoke skin phototoxic reactions related to generation of reactive oxygen species (ROS). Melanins are biopolymers synthesised in melanocytes - highly specialised cells, localised in the basal layer of epidermis. Production of melanin is a defence mechanism against harmful effects of UV radiation, ROS and many chemical substances, including drugs. In the present study the influence of oxytetracycline and UVA radiation on darkly pigmented melanocytes viability, the melanogenesis process and the activity of antioxidant enzymes were analysed. The obtained results show that oxytetracycline decreases cell viability in a dose-dependent manner. It has also been stated that UVA radiation as well as simultaneous exposure to oxytetracycline and UVA radiation reduce melanocytes viability. The tested drug alone exhibits little effect on antioxidant enzymes activity and has no influence on the synthesis of melanin. However, simultaneous exposure of the cells to oxytetracycline and UVA radiation causes an increase of SOD and GPx activity, a decrease of CAT activity as well as stimulates melanogenesis. The obtained results suggest that phototoxicity of oxytetracycline towards normal human melanocytes depends on both time of UVA exposure and the drug concentration.

Fluoroquinolone antibiotics provide broad-spectrum coverage for a number of infectious diseases, including respiratory as well as urinary tract infections. One of the important adverse effects of these drugs is phototoxicity which introduces a serious limitation to their use. To gain insight the molecular mechanisms underlying the fluoroquinolones-induced phototoxic side effects, the impact of two fluoroquinolone derivatives with different phototoxic potential, norfloxacin and moxifloxacin, on melanogenesis and antioxidant enzymes activity in normal human melanocytes HEMa-LP was determined. Both drugs induced concentration-dependent loss in melanocytes viability. The value of EC50 for these drugs was found to be 0.5 mM. Norfloxacin and moxifloxacin suppressed melanin biosynthesis; antibiotics were shown to inhibit cellular tyrosinase activity and to reduce melanin content in melanocytes. When comparing the both analyzed fluoroquinolones, it was observed that norfloxacin possesses greater inhibitory effect on tyrosinase activity in melanocytes than moxifloxacin. The extent of oxidative stress in cells was assessed by measuring the activity of antioxidant enzymes: SOD, CAT, and GPx. It was observed that norfloxacin caused higher depletion of antioxidant status in melanocytes when compared with moxifloxacin. The obtained results give a new insight into the mechanisms of fluoroquinolones toxicity directed to pigmented tissues. Moreover, the presented differences in modulation of biochemical processes in melanocytes may be an explanation for various phototoxic activities of the analyzed fluoroquinolone derivatives in vivo.

Streptomycin is an aminoglycoside antibiotic with an antituberculosis activity commonly used in clinical practice due to its good antimicrobial characteristics. A well-known undesirable side effect of this drug is ototoxicity, which may be caused by overproduction of reactive oxygen species and loss of melanocytes in the inner ear. The aim of this study was to examine the effect of streptomycin on melanogenesis and antioxidant defense system in cultured normal human melanocytes (HEMa-LP). Streptomycin induced concentration-dependent loss in melanocytes viability. The value of EC50 was determined to be ~5.0 mM. It has been shown that streptomycin causes inhibition of tyrosinase activity and reduces melanin content in human melanocytes in a concentration-dependent manner. Significant changes in the activity of cellular antioxidant enzymes: superoxide dismutase, catalase, and glutathione peroxidase were also stated. The results obtained in vitro may explain a potential role of melanocytes and melanin in the causative mechanisms of aminoglycosides ototoxic effects in vivo.

Fluoroquinolones are one of the most commonly prescribed classes of antibiotics. However, their use is often connected with high risk of phototoxic reactions that lead to various skin or eye disorders. The aim of this study was to examine the effect of ciprofloxacin, lomefloxacin, moxifloxacin and fluoroquinolone derivatives with different phototoxic potential, on the viability and melanogenesis in melanocytes.Normal human epidermal melanocytes, dark pigmented (HEMn-DP) were used as an in vitro model system. The effect of the tested antibiotics on cell viability and melanization in pigmented cells was investigated using a spectrophotometric method. The WST-1 assay was used to detect the cytotoxic effect of antibiotics.Ciprofloxacin, lomefloxacin and moxifloxacin induced the concentration-dependent loss in melanocytes viability. The values of ECThe results obtained in vitro suggest that the phototoxic potential of fluoroquinolones in vivo depends on specific drug-melanin interaction, the ability of drugs to affect melanogenesis as well as on the degree of melanocytes pigmentation.

Doxycycline is a commonly used tetracycline antibiotic showing the broad spectrum of antibacterial action. However, the use of this antibiotic is often connected with the risk of phototoxic reactions that lead to various skin disorders. One of the factors influencing the photosensitivity reactions is the melanin content in melanocytes. In this study, the impact of doxycycline and UVA irradiation on cell viability, melanogenesis and antioxidant defense system in cultured normal human epidermal melanocytes (HEMn-DP) was examined. The exposure of cells to doxycycline and UVA radiation resulted in concentration-dependent loss in melanocytes viability and induced melanin biosynthesis. Significant changes were stated in cellular antioxidant enzymes activity: SOD, CAT and GPx, which indicates alterations of antioxidant defense system. The results obtained in vitro may explain the mechanisms of phototoxic reactions that occur in normal human epidermal melanocytes in vivo after exposure of skin to doxycycline and UVA radiation.

Tetracycline is a semisynthetic antibiotic and is used in several types of infections against both gram-positive and gram-negative bacteria. This therapy is often associated with phototoxic reactions that occur after exposure to UV radiation and lead to photo-onycholysis, pseudoporphyria, solar urticaria and the fixed drug eruption in the skin. The phototoxic reactions may be related to the melanin content which, on one side may bind drugs - leading to their accumulation, and on the other side, they have photoprotective and antioxidant properties. In this study the effect of tetracycline and UVA irradiation on cell viability, biosynthesis of melanin and antioxidant defense system in cultured normal human epidermal melanocytes (HEMn-DP) was analyzed. The viability of the cells treated with tetracycline and exposed to UVA radiation decreased in a drug concentration-dependent manner. At the same time, the induction of the melanization process was observed. The significant alterations in antioxidant defense system, on the basis of changes in SOD, CAT and GPx activities, were stated. The obtained results may give explanation for the phototoxic effects of tetracycline therapy observed in skin cells exposed to UVA radiation.

Background Fluoroquinolones are a group of broad spectrum bactericidal antibiotics used to treat various infections of urinary and respiratory systems, as well as in ophthalmology and dermatology. This class of antibiotics causes toxic effects directed to pigmented tissues, what introduces a serious limitation to their use. The aim of this work was to examine the impact of sparfloxacin on melanogenesis and the antioxidant defense system in normal human epidermal melanocytes, adult, lightly pigmented (HEMa-LP). Methods The effect of sparfloxacin on cell viability was determined by WST-1 assay; melanin content, tyrosinase activity as well as antioxidant enzymes activity were measured spectrophotometrically. Results Sparfloxacin induced the concentration – dependent loss in melanocytes viability. The value of EC 50 was determined to be ∼0.25 mM. Sparfloxacin inhibited tyrosinase activity and reduced the melanin content in human melanocytes. To study the antioxidant defense system in melanocytes, the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in cells exposed to sparfloxacin were determined. It was observed that sparfloxacin caused depletion of the antioxidant status of melanocytes. Conclusions The observed sparfloxacin-dependent inhibition of melanogenesis and changes of antioxidant enzymes activities in human melanocytes give a new insight into the mechanism of fluoroquinolones toxicity directed to pigmented tissues.

Aminoglycosides, broad spectrum aminoglycoside antibiotics, are used in various infections therapy due to their good antimicrobial characteristics. However, their adverse effects such as nephrotoxicity and auditory ototoxicity, as well as some toxic effects directed to pigmented tissues, complicate the use of these agents. This study was undertaken to investigate the effect of aminoglycoside antibiotic-kanamycin on viability, melanogenesis and antioxidant enzymes activity in cultured human normal melanocytes (HEMa-LP). It has been demonstrated that kanamycin induces concentration-dependent loss in melanocytes viability. The value of EC50 was found to be ~6.0 mM. Kanamycin suppressed melanin biosynthesis: antibiotic was shown to inhibit cellular tyrosinase activity and to reduce melanin content in normal human melanocytes. Significant changes in the cellular antioxidant enzymes: SOD, CAT and GPx were stated in melanocytes exposed to kanamycin. Moreover, it was observed that kanamycin caused depletion of antioxidant defense sytem. It is concluded that the inhibitory effect of kanamycin on melanogenesis and not sufficient antioxidant defense mechanism in melanocytes in vitro may explain the potential mechanisms of undesirable side effects of this drug directed to pigmented tissues in vivo.

Amikacin is principally used to treat infections caused by microorganisms resistant to other aminoglycosides. Ototoxicity is one of the side effects of amikacin, but the causative mechanism of damage to the ear has not been fully established. Thus, the aim of this work was to examine the impact of amikacin on the melanogenesis and antioxidant defense system in cultured human normal melanocytes (HEMa-LP). Amikacin induced the concentration - dependent loss in melanocytes viability. The value of EC50 was determined to be ~7.5 mM. The analyzed antibiotic inhibited melanin biosynthesis in concentration-dependent manner. Increasing the amikacin concentration also resulted in a decrease in cellular tyrosinase activity. To study the antioxidant defense system in melanocytes, the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in cells exposed to amikacin were determined. Significant changes in cellular antioxidant enzymes activities were observed. Modulation of melanogenesis and the antioxidant status of melanocytes resulting from the use of amikacin in vitro may explain a potential role of melanin and melanocytes in the mechanisms of aminoglycosides ototoxic effects in vivo.

Backround Lomefloxacin is a potent bactericidal antibiotic. The use of this drug in treatment of various infections is accompanied by serious adverse effects on pigmented tissues. The exact mechanisms of lomefloxacin side effects have not been well established yet. The aim of this study was to characterize the interaction between lomefloxacin and ś, and to examine how this interaction affects the cell viability and melanization in melanocytes. Methods Normal human epidermal melanocytes and the model DOPA-ś were used. The binding parameters of lomefloxacin-ś complexes as well as the antibiotic effect on cell viability and melanization in pigmented cells were investigated using a spectrophotometric method. Results Our results indicate that lomefloxacin forms stable complexes with ś. The analysis of drug binding to ś has shown that at least two classes of independent binding sites are involved in formation of these complexes. The WST-1 assay was used to detect the antibiotic cytotoxic effect. The value of ED 50 for lomefloxacin was about 0.75 mmol/l. It has been shown that lomefloxacin causes inhibition of tyrosinase activity, and reduces ś content in human skin melanocytes in a dose-dependent manner. Conclusion The ability of the analyzed fluoroquinolone to form complexes with ś, and the demonstrated inhibitory effect on a melanization process in melanocytes in vitro may explain a potential role of ś biopolymer in the mechanisms of undesirable side effects of lomefloxacin in vivo resulting from its accumulation in pigmented tissues.

There have been described serious adverse events caused by ciprofloxacin in pigmented tissues. It is known that some fluoroquinolones bind well to melanin rich tissues, but the relation between their affinity to melanin and the skin or eye toxicity is not well documented. The aim of this study was to examine whether ciprofloxacin binds to melanin, and how this interaction affects the proliferation and melanization in melanocytes. We have demonstrated that complexes which ciprofloxacin forms with melanin possess at least two classes of independent binding sites. Their association constants are K(1)~10(5) M(-1) and K(2)~10(2) M(-1), respectively. Ciprofloxacin has induced evident concentration-dependent loss in melanocytes viability. The value of ED(50) was found to be ~0.5 mM. It has also been shown that ciprofloxacin reduces melanin content, and decreases tyrosinase activity in human skin melanocytes. The ability of ciprofloxacin to interact with melanin and its inhibitory effect on melanization in melanocytes in vitro may explain a potential role of melanin in the mechanisms of ciprofloxacin toxic effects in vivo.

Thioridazine as an antipsychotic agent was extensively used to treat various psychotic disorders, e.g. schizophrenia. However, the therapy with this drug can induce serious side effects such as extrapyramidal symptoms or ocular and skin disorders, which mechanisms are still not fully established. To gain inside the molecular mechanisms underlying thioridazine toxicity, we examined the effect of this drug on cell viability, antioxidant defence system as well as melanogenesis in normal human melanocytes. It was demonstrated that thioridazine induces concentration-dependent loss in cell viability. The value of EC50 was calculated to be 2.24 μM. To study the effect of thioridazine on antioxidant defence system in melanocytes, the level of hydrogen peroxide and the activities of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase were determined. The drug in concentrations of 0.1, 0.25, 1.0 and 2.5 μM caused changes in cellular antioxidant defence system indicating the induction of oxidative stress. It was also shown that the analysed neuroleptic in concentrations of 1.0 and 2.5 μM significantly inhibited melanogenesis. The observed changes in cell viability, antioxidant defence system and melanization in normal human melanocytes after thioridazine treatment may explain an important role of reactive oxygen species as well as melanin in mechanisms involved in this drug side effects directed on pigmented tissues.

Nicotine is a compound of tobacco plants and is responsible for addictive properties of tobacco which is used by about one billion of smokers all over the world. Recently, nicotine has drawn even more attention due to its presumed neuroprotective and antioxidant features as far as common use in various forms of smoking cessation therapies. It is suggested that nicotine may be accumulated in human tissues containing melanin. This may in turn influence biochemical processes in human cells producing melanin. The aim of this study was to examine the impact of nicotine on melanogenesis and antioxidant defense system in cultured normal human melanocytes (HEMn-DP). Nicotine induced concentration-dependent loss in melanocytes viability. The value of EC50 was determined to be 2.52 mM. Nicotine modulated melanin biosynthesis in normal human melanocytes. Significant changes in hydrogen peroxide content and cellular antioxidant enzymes: SOD, CAT, and GPx activities were stated in melanocytes exposed to nicotine, which indicates alterations of antioxidant defense system. The results obtained in vitro may explain a potential influence of nicotine on biochemical processes in melanocytes in vivo during long-term exposition to nicotine.