RESUMO
Cutaneous melanoma emerges from the malignant transformation of melanocytes and is the most aggressive type of skin cancer. The progression can occur in different stages: radial growth phase (RGP), vertical growth phase (VGP), and metastasis. Reactive oxygen species contribute to all phases of melanomagenesis through the modulation of oncogenic signaling pathways. Tetrahydrobiopterin (BH4) is an important cofactor for NOS coupling, and an uncoupled enzyme is a source of superoxide anion (O2â¢-) rather than nitric oxide (NO), altering the redox homeostasis and contributing to melanoma progression. In the present work, we showed that the BH4 amount varies between different cell lines corresponding to distinct stages of melanoma progression; however, they all presented higher O2â¢- levels and lower NO levels compared to melanocytes. Our results showed increased NOS expression in melanoma cells, contributing to NOS uncoupling. BH4 supplementation of RGP cells, and the DAHP treatment of metastatic melanoma cells reduced cell growth. Finally, Western blot analysis indicated that both treatments act on the PI3K/AKT and MAPK pathways of these melanoma cells in different ways. Disruption of cellular redox homeostasis by the altered BH4 concentration can be explored as a therapeutic strategy according to the stage of melanoma.
Assuntos
Melanoma , Neoplasias Cutâneas , Biopterinas/análogos & derivados , Biopterinas/metabolismo , Homeostase , Humanos , Melanoma/patologia , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Oxirredução , Fosfatidilinositol 3-Quinases/metabolismoRESUMO
PURPOSE: To describe a technique to obtain guinea pigs cochlear fluids and measure nitric oxide (NO) concentration. METHODS: Six guinea pigs were used and sacrificed. The cochlear fluids collected for measurement of NO, performed by chemiluminescence (NOA 280). RESULTS: Through the chemiluminescence was possible to analyze the concentration of NO in cochlear fluids obtained. Average levels of nitric oxide from guinea pigs was 12.55 µM. CONCLUSION: It is possible to obtain nitric oxide cochlear fluids, with this technique and nitric oxide concentration measure by chemiluminescence, a quantitative and more precise method.
Assuntos
Cóclea/metabolismo , Óxido Nítrico/análise , Animais , Cóclea/cirurgia , Cobaias , Luminescência , Masculino , Modelos Animais , Óxido Nítrico Sintase/análise , Reprodutibilidade dos TestesRESUMO
PURPOSE: To describe a technique to obtain guinea pigs cochlear fluids and measure nitric oxide (NO) concentration. METHODS: Six guinea pigs were used and sacrificed. The cochlear fluids collected for measurement of NO, performed by chemiluminescence (NOA 280). RESULTS: Through the chemiluminescence was possible to analyze the concentration of NO in cochlear fluids obtained. Average levels of nitric oxide from guinea pigs was 12.55 µM. CONCLUSION: It is possible to obtain nitric oxide cochlear fluids, with this technique and nitric oxide concentration measure by chemiluminescence, a quantitative and more precise method.