ABSTRACT
PURPOSE: Melanoma is an aggressive form of skin cancer. The aim of the study was to evaluate the influence of UVA radiation and psoralens: 5-methoxypsoralen (5-MOP) or 8-methoxypsoralen (8-MOP) on melanoma cells viability. MATERIALS AND METHODS: The amelanotic C32 and melanotic COLO829 human melanoma cell lines were exposed to increasing concentrations of psoralens (0.1-100 µM) in the presence or absence of UVA radiation. Cell viability was evaluated by the WST-1 assay. RESULTS: We demonstrated that 8-MOP, in contrast to 5-MOP, has no cytotoxic effect on both melanoma cell lines. Simultaneous exposure of cells to 8-MOP and UVA radiation caused significant cytotoxic response in C32 cells where the EC50 value was estimated to be 131.0 µM (UVA dose: 1.3 J/cm2) and 105.3 µM (UVA dose: 2.6 J/cm2). The cytotoxicity of 5-MOP on both C32 and COLO829 cells was significantly augmented by UVA radiation - the EC50 was estimated to be 22.7 or 7.9 µM (UVA dose: 1.3 J/cm2) and 24.2 or 7.0 µM (UVA dose: 2.6 J/cm2), respectively. CONCLUSIONS: The demonstrated high cytotoxic response after simultaneous exposure of melanoma cells to psoralens and UVA radiation in vitro suggests the usefulness of PUVA therapy to treat melanoma in vivo.
Subject(s)
Cell Survival/drug effects , Cell Survival/radiation effects , Melanoma/drug therapy , Melanoma/pathology , PUVA Therapy/methods , 5-Methoxypsoralen , Cell Line, Tumor , Dose-Response Relationship, Drug , Dose-Response Relationship, Radiation , Drug Synergism , Humans , Methoxsalen/administration & dosage , Methoxsalen/analogs & derivatives , Radiotherapy Dosage , Treatment OutcomeABSTRACT
Paracetamol (acetaminophen) is commonly used as a drug of choice for treatment of pain and fever. Unlike non-steroidal anti-inflammatory drugs (NSAIDs) it does not cause gastrointestinal damage or untoward cardiorenal effects, however cutaneous adverse effects have been reported. It is known that paracetamol binds to melanin biopolymers, but the relation between the affinity of this drug to melanin and its toxicity is not documented. The aim of this work was to examine the impact of paracetamol on melanogenesis in cultured human normal epidermal melanocytes (HEMn-DP). The effect of paracetamol on cell viability was determined by WST-1 assay, melanin content and tyrosinase activity were measured spectrophotometrically. It has been demonstrated that paracetamol induced concentration-dependent loss in melanocytes viability. The value of EC50 was found to be - 20.0 mM. The analyzed drug inhibited melanin biosynthesis in a concentration-dependent manner by decreasing the melanin content as well as the tyrosinase activity. The demonstrated inhibitory effect of paracetamol on melanization process in normal epidermal melanocytes in vitro may explain the potential role of melanin biopolymer in the mechanisms of undesirable side effects of this drug in vivo, as a result of its accumulation in pigmented tissues.
