RADIOSENSITIZING EFFECT OF RHOB PROTEIN IN MELANOMA CELLS

NOTCOVICH, C.; SÁNCHEZ CRESPO, R.; GRISSI, C.; DELGADO, D.C.; MOLINARI, B.; IBAÑEZ, I. L.; DURÁN H.

Buenos Aires

Congreso; X Congreso Regional Latinoamericano IRPA de Protección y Seguridad Radiológica; 2015

Sociedad Argentina de Radioprotección (SAR), Asociación Internacional de Protección Radiológica

Melanoma cells are highly resistant to chemo or radiotherapy. DNA damage agents such as ionizing radiation induce apoptosis involving RhoB protein. In a great variety of tumors the levels of this protein decrease along tumor progression. RhoB is considered a tumor suppressor gene due to its antiproliferative and proapoptotic effect. Considering the aforementioned, the aim of this study was to characterize the radiobiological response of different human melanoma cell lines, and to evaluate the possible correlation between RhoB expression and radiosensitivity. The human melanoma cell lines A375, MELJ and SB2 were gamma-irradiated (137Cs). Survival curves were obtained by clonogenic assay and fitted to the Linear-Quadratic (LQ) model. Radiosensitivity was evaluated by surviving fraction at 2 Gy (SF2). Results showed that MELJ was significantly more radioresistant (SF2=0.71) than A375 and SB2 (0.29 and 0.21 respectively). Expression levels of RhoB, evaluated by western blot, increased in all lines vs. non-irradiated control. SB2, the most radiosensitive cells, showed a greater induction (p