MODULATION OF OXIDATIVE STRESS IN BREAST CANCER CELL LINES (MCF-7), TIME-DEPENDENT TO THE USE OF MELATONIN ADSORBED TO THE PEG MICROSPHERE.

FERNADES, R.T.S (Federal University of Mato Grosso do Sul (UFMS).), TOZETTI, I.A (Federal University of Mato Grosso do Sul (UFMS).), PEREIRA, C.C.S (Federal University of Mato Grosso (UFMT)), DELUQUE, A.L (Federal University of Mato Grosso (UFMT)), MARCHI

Federal University of Mato Grosso (UFMT); Federal University of Mato Grosso do Sul (UFMS).The aim of this study was to evaluate the nanofractions of melatonin adsorbed to the PEG microsphere on the oxidative mechanisms of tumor cell lines (MCF-7) in diurnal and nocturnal periods. MCF-7cells were incubated during the day and night at 37°C for 24 h in a humid atmosphere containing 5% CO2 (carbon dioxide) in the presence or absence of melatonin adsorbed onto the PEG (polyethylene glycol) microsphere. After this period the culture supernatant was removed and reserved for CuZn-SOD (enzymatics of dismutase superoxide) quantification by the NBT (nitrotetrazolium blue) reduction method. Cells were resuspended in cytochrome C to verify the superoxide release. In the nocturnal period, it was observed increase in spontaneous release of superoxide by MCF-7 cells when incubated. The incubation of melatonin adsorbed to PEG microsphere also increased the superoxide release in the nocturnal period. When the MCF-7 cells were incubated in the nocturnal period it was observed lower SOD concentrations in culture supernatant. The treatement by melatonin, independently of PEG microspheres, also decrease the SOD levels. These data suggest that melatonin adsorbed to the PEG microsphere has pro-oxidative effect in the diurnal period and anti-oxidant at nocturnal period on the cells lines of breast cancer.breast cancer

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