Mechanisms Underlying the Adaptive Response against Spontaneous Neoplastic Transformation Induced by Low Doses of Low LET Radiation

J. Leslie Redpath
University of California, Irvine

Why This Project

We have observed that the spontaneous frequency of cell transformation is decreased by a small dose of radiation suggesting a protective response. This adaptive response was measured as a decrease in the number of cells that are changed from normal to cancer (cell transformation) following low doses of gamma radiation (<10 cGy). To investigate possible mechanisms responsible for the observed adaptive response and relate it to the risk for radiation-induced cancer at low doses.

Project Goals

1. Determine how low doses of radiation can reduce cell using our model tissue culture system, provides a means to
2. Evaluate three possible mechanisms that may explain adaptive response, DNA repair, the cells antioxidant status, and cell-cell communication.
3. Examine how this protective response is altered by radiation type

Research Approach

For these basic studies, we measure radiation induced cell transformation in the same human hybrid cell model system which we previously used. Past studies have been doneto study gamma radiation. Experiments are currently in progress to construct dose-response relationships for cell transformation using x-rays. We will use x-ray with the same energy used in radiological diagnostic procedures.

Expected Outcomes

1. Predict the reletive risk for exposure to x-rays and gamma rays
2. Link risks associated with low level exposures to low-LET radiation in humans to that in this model system.

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