Saturday, February 16, 2013
Auditorium/Exhibit Hall C (Hynes Convention Center)
Background: The Adaptive Response (AR) is a protective phenomenon in which cells or animals exposed to a low-dose of ionizing radiation are transiently protected against a variety of effects from subsequent higher exposures. In the present studies human mammary epithelial cells (MCF10A) were used to investigate the effect of a low-dose exposure prior to a high challenging dose. Micronuclei (MN) were scored as markers of induced DNA damage, which appear as extra nuclear bodies that are formed from un- or mis-rejoined double strand breaks (dsb). Scoring the formation of MN in bi-nucleated cells can be used as a biomarker for genomic instability. Methods: MCF10A cells were grown in 2D mono-layers and 3D cell culture systems at atmospheric (20% O2) or physiological (3% O2) oxygen levels. MCF10A cells were exposed to a low adaptive dose of 10 cGy and challenged 4 hours later with a higher dose of 2 Gy of X-rays. Results: Mono-layer cell cultures were used to perform proliferation tests, and it was discovered that MCF10A cells grow slightly better under a more physiological oxygen concentration of 3%. Cells growing in the 3D gel matrices showed cell morphology more like intact tissue by forming acinar structures. Morphology studies in 3D showed that the branched tubular growth patterns occurred more often in 3% oxygen, which better mimics in vivo conditions. Conclusions: Future experiments will help us gain a better understanding of the effects of chronic low-dose radiation exposure to human cells by using a beta-ray emitter.