Involvement of H2O2 in WM35 Human Melanoma Cells Proliferation.

MASSARI N; MEDINA V; NUÑEZ M.; MARTÍN G; CRICCO G; BERGOC R; RIVERA E

Mar del Plata, Buenos Aires, Argentina

Congreso; XLIII Annual Meeting of SAIB, Sociedad Argentina de Investigación en Bioquímica y Biología Molecular,; 2007

INVOLVEMENT OFH O IN WM35 HUMAN MELANOMA CELLSPROLIFERATION 2 2 Massari NA, Medina VA, Nuñez M, Martin GA, Cricco GP, Bergoc RM, Rivera ES. Radioisotopes Laboratory, School of Pharmacy and Biochemistry, University of Buenos Aire s , Argentina. E-mail: nmassari@ffyb.uba.ar We have reported that histamine (HA) regulates signaling processes in melanoma cell lines. Accumulating evidence suggests that H O plays an essential role in cancer development and metabolism. In addition H O is related to cellular damage produced by ionizing radiation (IR). The aim of this work was to investigate the involvement of H O in the modulation ofWM35 cell proliferation. The expression of Catalase (CAT) and Bax were determined by western blot; intracellular H O by flow cytometry employing specific fluorescent staining and cell proliferation by clonogenic assay. Cells were irradiated with doses ranging from 0 to 10 Gy (137Cs source of 189 TBq). Results indicate that 10 M HA significantly reduced WM35 cell proliferation (50%) while increased intracellular H O levels; this effect was completely reverted by the addition of CAT (125 UI). CAT treatment enhanced proliferation (p<0.001), decreasing Annexin V positive cells and the expression of Bax. In accordance, H O decreased proliferation in a dose dependent manner (IC50=2.5 M). The surviving fraction after a dose of 2Gy was SF2Gy=0.35 and it was decreased after treatment with 1 MH O (SF2Gy=0.20). IR induced apoptosis and senescence. We conclude that H O levels are critical for WM35 melanoma cell proliferation and may be involved in the inhibitory action ofHAas well as in the cellular response against IR