Lithium may help radiation target cancer, spare heal...( Vanderbilt-Ingram Cancer Center inve...)

Vanderbilt-Ingram Cancer Center investigators have uncovered a mechanism that helps explain how lithium, a drug widely used to treat bipolar mood disorder, also protects the brain from damage that occurs during radiation treatments.

In the May 1 issue of the Journal of Clinical Investigation, Fen Xia, M.D., Ph.D., and colleagues show that lithium promotes DNA repair in healthy cells but not in brain tumor cells. The findings suggest that lithium treatment could offer a way to protect healthy brain tissue from damage that may occur during cranial radiation treatments.

Cranial irradiation is part of standard therapy for both primary and metastatic brain tumors. However, as with all treatment modalities, radiation often causes long-term side effects. In particular, neurological impairments including lowered IQ, learning difficulties and memory loss have been reported, especially in children treated for brain cancers. Radiation-induced damage to the healthy cells of the hippocampus, a brain structure crucial for learning and memory, is one likely source of these deficits.

These cognitive impairments have long-lasting effects on the quality of life for survivors, noted Xia, an assistant professor of Radiation Oncology and Cancer Biology.

"Because these patients can now survive longer and are being cured, alleviating long-term toxicity is becoming more important," she said.

Researchers have been searching for agents that could protect healthy brain tissue from radiation-induced damage. Previously, Vanderbilt-Ingram investigators led by Dennis Hallahan, M.D., chair of Radiation Oncology and the Ingram Professor of Cancer Research found that lithium treatment protects cultured hippocampal neurons from radiation-induced cell death and improves cognitive performance in irradiated mice.

But how lithium protects against radiation-induced damage is unclear.

Radiation kills tumor cells by damaging thei
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