Bystander effect induced by radiotherapeutic doses in breast carcinoma cell line

ZUBIRÍA, MG; MARTINEZ, M; DODAL, D; SANCHEZ, G; CASAS, O; GÜERCI, AM

Buenos Aires

Congreso; 12th International Congress of thr International Radiation Protection Association; 2008

Argentine Radiation Protection Society

Abstract. BYSTANDER EFFECT (BSE) refers to the observed effects in cells that have not been directly crossed by radiation and which are near the radiated cells. It is suggested that different communication and signaling cellular pathways, such as gap junctions and the release of diverse clastogenic factors (reactive oxygen species and citokynes), take place in this phenomenon. Delayed Genomic Instability (GI) could be explained by means of BSE and that could be showed by the cloning efficiency decrease, the apoptosis increase, point mutations, and micronuclei frequency. The relevance of this phenomenon is discussed in the carcinogenic process.  Besides, BSE is also important because of its impact on the present paradigm of the ionizing effect of radiation, essentially based on the Theory of the Target. The importance of this research on radiotherapy could be the optimization of the therapeutic effects of radiation. In the present study, the BSE was evaluated in breast carcinoma cell line MCF-7 by the application of both techniques: Comet Assay (alcaline version) and Clonogenic Assay. Conclusions: - ROS involvement in BSE was corroborated by Comet Assay in this cell line; - ICM treatment decreased cloning efficiency, checked by Clonogenic Assay. These results are very important for the reconsideration of the current paradigm of Target Theory and its application in radiobiology.