Interaction Between Ionizing Radiation, Estrogens and Antiestrogens in the Modification of Tumor Microenvironment in Estrogen Dependent Multicellular Spheroids

• DOI: 10.3109/02841869509094000
• Publication Date: 2007-11-27T08:15:26Z
• Authors: Mercedes Villalobos; Manuel Aranda; Maria Isabel Nunez; Diego Becerra; Nicoles Olea; Marian Ruiz de Al...; Vincente Pedraza
• Keywords: Spheroid; Radiosensitivity; Radioresistance; Antiestrogen; Radiobiology

MCF7 human breast cancer cells growing as multicellular spheroids were examined a model of three-dimensional cellular organization. Estrogen-free medium inhibited spheroid formation. In containing estrogens, the antiestrogen hydroxytamoxifen decreased growth rate. Analyses with recursion formula after Gompertz fitting showed that rate exponential decrease in (alpha) was alpha 0.099 +/- 0.013 d-1, and alpha' 0.061 0.015 d-1 for 0.1 microM control respectively. which had been arrested an estrogen-free significant radiosensitivity (surviving fraction at 2 Gy, SF2 = 63%) when compared nM 17 beta-estradiol-treated (SF2 38%). No differences seen estrogen-supplemented (radiation dose necessary to 50% (SCD50) 5.51 Gy; derived alpha, beta 0.301 0.110 Gy-1, 0.018 0.005 Gy-2, 51% respectively) monolayer cultures same (alpha 0.316 0.059 0.023 0.006 Gy-2 50%). model, manipulating environment, i.e., estrogen treatment, modulates sensitivity ionizing radiation.