The effect of sulindac on redox homeostasis and apoptosis-related proteins in melanotic and amelanotic cells.

BACKGROUND: Non-steroidal anti-inflammatory drugs have been shown to inhibit the development of induced neoplasms. Our previous research demonstrated that the cytotoxicity of sulindac against melanoma cells is comparable to dacarbazine, the drug used in chemotherapy. The aim of this study was to investigate the mechanism of sulindac cytotoxicity on COLO 829 and C32 cell lines. METHODS: The influence of sundilac on the activity of selected enzymes of the antioxidant system (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)) and the content of hydrogen peroxide as well as the level of proteins initiating (p53, Bax) and inhibiting (Bcl-2) apoptosis were measured in melanoma cells. RESULTS: In melanotic melanoma cells, sulindac increased the activity of SOD and the content of H2O2 but decreased the activity of CAT and GPx. The level of p53 and Bax proteins rose but the content of Bcl-2 protein was lowered. Similar results were observed for dacarbazine. In amelanotic melanoma cells, sulindac did not cause an increase in the activity of measured enzymes or any significant changes in the level of apoptotic proteins. CONCLUSION: The cytotoxic effect of sulindac in the COLO 829 cell line is connected to disturbed redox homeostasis by changing the activity of SOD, CAT, GPx, and level of H2O2. Sulindac also induces apoptosis by changing the ratio of the pro-apoptotic/anti-apoptotic protein. The presented studies indicate the possibility of developing target therapy against melanotic melanoma using sulindac.

Effect of norfloxacin and moxifloxacin on melanin synthesis and antioxidant enzymes activity in normal human melanocytes.

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.

[Hypomelanoses transmitted from generation to generation]. / Hipomelanozy przekazywane z pokolenia na pokolenie.

Inherited diseases of pigmentation were among the first traits studied in humans because of their easy recognition. This article presents selected hypopigmentary disorders, which can be divided into hypomelanocytoses and hypomelanoses. Hereditary hypomelanoses are caused by abnormal melanin biosynthesis as well as by abnormal transfer of mature melanosomes to melanocyte dendrites and to neighboring cells. These disorders are represented by oculocutaneous albinism, Hermansky-Pudlak syndrome, Chediak-Higashi syndrome, Griscelli syndrome, Menkes syndrome and phenylketonuria, and are caused by different mutations of the following genes: TYR, P, TRP1, MATP, HPS, CHS, MYO5A, RAB27A, MLPH, ATP7A and PAH. Oculocutaneous albinism is caused by a deficiency of melanin pigment in the skin, hair, and eye and results from mutations in the TYR, P, TRP1 and MATP genes involved in the biosynthesis of melanin pigment. Mutations in the HPS, CHS, MYO5A, RAB27A and MLPH genes, which regulate the biogenesis, maturation and transfer of me-lanosomes to neighboring cells, are responsible for such disorders as Hermansky-Pudlak, Chediak-Higashi and Griscelli syndromes. In turn, mutations of the ATP7A and PAH genes, regulating intracellular copper concentration and activity of phenylalanine hydroxylase, lead to Menkes syndrome and phenylketonuria.

[Hereditary hypomelanocytoses: the role of PAX3, SOX10, MITF, SNAI2, KIT, EDN3 and EDNRB genes]. / Hipomelanocytozy dziedziczne: rola genów PAX3, SOX10, MITF, SNAI2, KIT, EDN3 i EDNRB.

Hypo- and hyperpigmentation disorders are the most severe dermatological diseases observed in patients from all over the world. These disorders can be divided into melanoses connected with disorders of melanocyte function and melanocytoses connected with melanocyte development. The article presents some hereditary hypomelanocytoses, which are caused by abnormal melanoblast development, migration and proliferation as well as by abnormal melanocyte viability and proliferation. These disorders are represented by Waardenburg syndrome, piebaldism and Tietz syndrome, and are caused by different mutations of various or the same genes. The types of mutations comprise missense and nonsense mutations, frameshifts (in-frame insertions or deletions), truncating variations, splice alterations and non-stop mutations. It has been demonstrated that mutations of the same gene may cause different hypopigmentation syndromes that may have similar phenotypes. For example, mutations of the MITF gene cause Waardenburg syndrome type 2A as well as Tietz syndrome. It has also been demonstrated that mutations of different genes may cause an identical syndrome. For example, mutations of MITF, SNAI2 and SOX10 genes are observed in Waardenburg syndrome type II and mutations of EDNRB, EDN3 and SOX10 genes are responsible for Waardenburg syndrome type IV. In turn, mutation of the KIT gene and/or heterozygous deletion of the SNAI2 gene result in piebaldism disease. The knowledge of the exact mechanisms of pigmentary disorders may be useful in the development of new therapeutic approaches to their treatment.